NEAR INFRARED DYES FOR BIOLOGICAL IMAGING AND OPTOELECTRONIC DEVICES
20240124714 ยท 2024-04-18
Assignee
Inventors
Cpc classification
G01N1/30
PHYSICS
C09B67/0063
CHEMISTRY; METALLURGY
C09B11/28
CHEMISTRY; METALLURGY
International classification
C09B11/28
CHEMISTRY; METALLURGY
C09K11/02
CHEMISTRY; METALLURGY
Abstract
A near infrared dye comprising a counterion and a structure of Formula I
##STR00001##
wherein the at least one of R.sub.1 and R.sub.2are 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine, and X, R, R.sub.3-R.sub.4, R.sub.19, R.sub.20 and R.sub.22-R.sub.29 are disclosed herein. Materials and compositions comprising the NIR dye can absorb light in the NIR I & II regions and then the energy can be released in the form of light (fluorescence) or heat (non-radiative). The dyes can also convert the absorbed light to heat and ultrasound waves via the photoacoustic effect. The photoacoustic effect can be used in photoacoustic tomography to image biological materials or processes. Methods for synthesizing the NIR dyes and materials comprising the same are also disclosed.
Claims
1. A near infrared dye comprising a counterion and a structure of Formula I ##STR00018## wherein X is selected from O, Si and P; R is selected from hydrogen, C(O)OH, a substituted or unsubstituted linear or branched C.sub.1-C.sub.18 alkyl group, a substituted or unsubstituted linear or branched C.sub.2-C.sub.18 alkenyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted linear or branched C.sub.1-C.sub.18 alkoxy group, an ester group represented by the formula C(O)OA.sup.1, wherein A.sup.1 is a substituted or unsubstituted linear or branched C.sub.1-C.sub.18 alkyl group, a substituted or unsubstituted linear or branched C.sub.2-C.sub.18 alkenyl group or a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, an amide group represented by the formula C(O)N(A.sup.2).sub.2, wherein A.sup.2 is selected from a substituted or unsubstituted linear or branched C.sub.1-C.sub.18 alkyl group, a substituted or unsubstituted linear or branched C.sub.2-C.sub.18 alkenyl group, or a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, or an ether group represented by the formula CH.sub.2OA.sup.3 wherein A.sup.3 is selected from a substituted or unsubstituted linear or branched C.sub.1-C.sub.18 alkyl group, a substituted or unsubstituted linear or branched C.sub.2-C.sub.18 alkenyl group, or a or a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group; when X is O, then R.sub.3 and R.sub.4 are absent, and when X is Si, then R.sub.3 and R.sub.4 are each singly bonded to the Si atom, and are independently selected from, hydrogen, a substituted or unsubstituted C.sub.1-C.sub.18 linear or branched alkyl group or a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, when X is P, then R.sub.3 is singly bonded to the P atom and is selected from hydrogen, a substituted or unsubstituted C.sub.1-C.sub.18 linear or branched alkyl group or a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group is P, and R.sub.4 is singly bonded to the P and is a substituted or unsubstituted C.sub.1-C.sub.18 linear or branched alkyl group or a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group or R.sub.4 is doubly bonded to the P and is an oxygen; wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are each independently selected from hydrogen, sulfonate, halogen, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, and an alkoxy group having 1 to 20 carbon atoms or wherein one or more pair of R.sub.22 and R.sub.23, R.sub.24 and R.sub.25, R.sub.25 and R.sub.26, R.sub.26 and R.sub.27, R.sub.27 and R.sub.28, R.sub.28 and R.sub.29, together with the carbons they are attached form a saturated or unsaturated 6 membered ring; and R.sub.1 and R.sub.2 are both selected from one of the following Groups A, B and C: Group A R.sub.1 is hydrogen and R.sub.2 is a donor which is substituted or unsubstituted and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine; or Group B both R.sub.1 and R.sub.2 are the same donors and both are substituted or unsubstituted, and are selected from 1-(thiophen-2-yl)piperidine group, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, and 1-([2,2-bithiophen]-5-yl)piperidine; or Group C R.sub.1 and R.sub.2 are different donors and R.sub.1 is a donor which is substituted or unsubstituted and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine and R.sub.2 is a donor which is substituted or unsubstituted and is selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, C.sub.2-C.sub.12 dialkyl amino, indolizine-3-yl, diphenylamino, and julolidinyl.
2. The NIR dye of claim 1, wherein X is O, and R.sub.3 and R.sub.4 are absent; R is C(O)OH, or R is an ester group, an amide group, or an ether group and A.sup.1, A.sup.2, and A.sup.3 are independently selected from a linear or branched CI-CB alkyl group, a linear or branched C.sub.2-C.sub.18 alkenyl group, or a C.sub.3-C.sub.10 cycloalkyl group that is substituted with 1 to 3 substituents independently selected from a halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms.
3. The NIR dye of claim 1, wherein X is 0, and R.sub.3 and R.sub.4 are absent; R is C(O)OH or an ester group represented by the formula C(O)OA.sup.1 wherein A.sup.1 and A.sup.2 are independently selected from a linear or branched C.sub.1-C.sub.6 alkyl group; R.sub.1 and R.sub.2 are both selected from one of the following Groups A and B: Group A R.sub.1 is hydrogen and R.sub.2 is a donor which is substituted with 0 to 3 substituents and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine; or Group B both R.sub.1 and R.sub.2 are the same donors and both are substituted with 0 to 3 substituents, and are selected from 1-(thiophen-2-yl)piperidine group, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, and 1-([2,2-bithiophen]-5-yl)piperidine; wherein the substituents are independently selected from a halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbons, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an alkylether having 2-20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbons, and an alkoxy group having 1 to 20 carbon atoms.
4. The NIR dye of claim 1, wherein X is O, and R.sub.3 and R.sub.4 are absent; R is C(O)OH or an ester group represented by the formula C(O)OA.sup.1 wherein A.sup.1 and A.sup.2 are independently selected from a linear or branched C.sub.1-C.sub.6 alkyl group; R.sub.1 and R.sub.2 are both selected from Group C: Group C R.sub.1 and R.sub.2 are different donors and R.sub.1 is a donor which is substituted with 0 to 3 substituents and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine and R.sub.2 is a donor which is substituted with 0 to 3 substituents, and is selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, ([2,2-bithiophen]-5-yl)piperidine, C.sub.2-C.sub.12 dialkyl amino, indolizine-3-yl, diphenylamino, and julolidinyl; wherein the substituents are independently selected from a halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms.
5. The NIR dye of claim 1, wherein X is O, and R.sub.3 and R.sub.4 are absent; R is C(O)OH or an ester group represented by the formula C(O)OA.sup.1 wherein A.sup.1 and A.sup.2 are independently selected from a linear or branched C.sub.1-C.sub.6 alkyl group; R.sub.1 and R.sub.2 are both selected from Group C: Group C R.sub.1 and R.sub.2 are different donors and R.sub.1 is a donor which is substituted with 0 to 3 substituents and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine and R.sub.2 is a donor which is substituted with 0 to 3 substituents and is selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, diethyl amino, and julolidinyl; wherein the substituents are independently selected from a halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms.
6. The NIR dye of claim 1, wherein the counterion is nitrite, sulfate, phosphate, bicarbonate, trifluoroacetate, pentafluoropropanoate, chloride, bromide, iodide, perchlorate, nitrate, benzenesulfonate, p-toluenesulfonate, methyl sulfate, ethyl sulfate, propyl sulfate, tetrafluoroborate, tetraphenylborate, hexafluorophosphate, benzenesulfinate, acetate, trifluoroacetate, propionacetate, benzoate, oxalate, succinate, malonate, oleate, stearate, citrate, monohydrogen diphosphate, dihydrogen monophosphate, pentachlorostannate, chlorosulfonate, fluorosulfonate, trifluoromethansulfonate, hexafluoroarsenate, hexafluoroantimonate, molybdenate, tungstate, titanate, zirconate ions, or any combination thereof.
7. The NIR dye of claim 1, wherein the counterion is trifluoroacetate, pentafluoropropanoate, chloride, bromide, iodide, fluorosulfonate, and trifluoromethansulfonate.
8. The NIR dye of claim 1, wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are each independently selected from hydrogen, sulfonate, halogen, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 6 carbon atoms, alkenyl group having 2 to 6 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 6 to 10 carbon atoms, and wherein 0 or 1 pair of R.sub.22 and R.sub.23, R.sub.24 and R.sub.25, R.sub.25 and R.sub.26, R.sub.26 and R.sub.27, R.sub.27 and R.sub.28, R.sub.28 and R.sub.29, together with the carbons they are attached from form a saturated or unsaturated 6 membered ring.
9. The NIR dye of claim 1, wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are each independently selected from hydrogen, halogen, hydroxy, an alkyl group having 1 to 6 carbon atoms, and a phenyl.
10. The NIR dye of claim 1, wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are each hydrogen.
11. The NIR dye of claim 1, wherein the NIR dye has one of the following structures: ##STR00019## ##STR00020##
12. The NIR dye of claim 1, wherein the NIR dye absorbs light in the NIR I region and/or the NIR II region; or wherein the NIR dye absorbs light in the NIR II region; or wherein the NIR dye has an absorption maximum in the NIR II region.
13. A composite comprising the NIR dye of claim 1 in a polymer matrix.
14. The composite according to claim 13, wherein the polymer matrix is solid at room temperature.
15. A method for making a NIR dye, the method comprising: (a) performing a CH arylation reaction by combining a Donor and an Acceptor of Formula II with a catalyst in a solvent to form a reaction mixture, ##STR00021## wherein R.sub.18 and R.sub.21 are individually selected from Cl, Br, I and OSO.sub.2R.sub.52 wherein R.sub.52 is a hydrogen or lower alkyl; wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are each independently selected from hydrogen or an alkyl group having 1 to 20 carbons, or wherein one or more pair of R.sub.22 and R.sub.23, R.sub.24 and R.sub.25, R.sub.25 and R.sub.26, R.sub.26 and R.sub.27, R.sub.27 and R.sub.28, R.sub.28 and R.sub.29, together with the carbons they are attached form a saturated or unsaturated 6 membered ring; and wherein the Donor(s) is substituted or unsubstituted and comprises at least one from Group (X) and one from Group (Y): (X) 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine; and (Y) 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, C.sub.2-C.sub.12 dialkyl amine, indolizine, diphenylamine, and julolidine, to thereby replace the groups at R.sub.18 and R.sub.21 with said Donor(s); (b) a ring opening reaction by transesterification with an alcohol to give the NIR dye of Formula I ##STR00022## wherein X is O, and R.sub.3 and R.sub.4 are absent; R is selected from C(O)OH or an ester group represented by the formula C(O)OA.sup.1, wherein A.sup.1 is a linear or branched C.sub.1-C.sub.18 alkyl group; wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are as described above; and R.sub.1 and R.sub.2 are both selected from one of the following Groups B and C: Group B both R.sub.1 and R.sub.2 are the same donors and both are substituted or unsubstituted, and are selected from 1-(thiophen-2-yl)piperidine group, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, and 1-([2,2-bithiophen]-5-yl)piperidine; or Group C R.sub.1 and R.sub.2 are different donors and R.sub.1 is a donor which is substituted or unsubstituted and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine and R.sub.2 is a donor which is substituted or unsubstituted and is selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, C.sub.2-C.sub.12 dialkyl amino, indolizine-3-yl, diphenylamino, and julolidinyl.
16. The method for making a NIR dye of claim 15, wherein the catalyst in step (a) is a palladium compound.
17. The method for making a NIR dye of claim 15, wherein the compound of Formula II is as follows: ##STR00023##
18. The method for making a NIR dye of claim 15, wherein the compound formed in step (a) has the following structure: ##STR00024##
19. A composition comprising the NIR dye of claim 1 and a pharmaceutically-acceptable carrier or a solid polymer matrix.
20. A method for imaging a biological sample, the method comprising: (a) contacting the biological sample with an effective amount of the composition of claim 19; (b) exposing the biological sample and the composition to NIR radiation; and (c) observing photoacoustic resonance or fluorescence in the biological sample.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0078]
[0079]
[0080]
[0081]
[0082]
[0083]
[0084]
[0085]
[0086] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
DETAILED DESCRIPTION
[0087] Small molecule organic dyes may be attractive for clinical applications because of their tendency to metabolize in the cells and their potential for low toxicity. Disclosed herein is a method for development of NIR organic dyes by combining donor and acceptor groups. In one aspect, the choice of a good donor-acceptor pair can significantly lower the optical bandgap of a dye due to the promotion of charge transfer events.
[0088] The novel NIR dyes can be used in biological imaging such as in vivo photoacoustic or fluorescence imaging of tumor angiogenesis monitoring, blood oxygenation mapping, functional brain imaging, skin melanoma detection, methemoglobin measuring, etc. In one aspect, the disclosure provides new materials that absorb light in the NIR I & II regions where biological tissues are most transparent. In a further aspect, the compositions allow for direct, real-time laser imaging of biological samples at a faster, more affordable rate than an MRI, while also potentially allowing real time analysis during surgery, as one example.
[0089] The xanthene-based dyes of the disclosure have outstanding photophysical properties and stimuli responses. For instance, the new NIR xanthene-based PA imaging agent XanthCR-880 shown in
[0090] XanthCR-880 was developed using the donor-acceptor-donor (D-A-D) design. The design of the dye was based on two factors: (i) a good overlap of the thiophene donor and xanthene acceptor to lower the bandgap of the dye due to charge transfer events and (ii) an amino group connected to the thiophene to increase donor strength in the push-pull mechanism of xanthene-based dyes.
Donors
[0091] The xanthene dyes can be in a donor-acceptor (D-A) design or a donor-acceptor-donor (D-A-D) design. For the D-A-D design, the donors can be symmetrical or unsymmetrical. For symmetrical dyes, R.sub.1 and R.sub.2 are based on identical donors. For unsymmetrical dyes, R.sub.1 and R.sub.2 are not identical.
[0092] Although the structures described and drawn herein show the cationic charge on a single atom, the donors can be in resonance with one another such that the cationic charge can move from the donor at R.sub.1 to the donor at R.sub.2. R.sub.1 and R.sub.2 can be selected from one of the following Groups A, B and C:
Group A
[0093] R.sub.1 is hydrogen and R.sub.2 is a donor which is a substituted or unsubstituted 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine; or
Group B (Symmetrical Dyes)
[0094] Both R.sub.1 and R.sub.2 are the same donors and both are substituted or unsubstituted, and both are selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, and 1-([2,2-bithiophen]-5-yl)piperidine; or
Group C (Unsymmetrical Dyes)
[0095] R.sub.2 is a different donor from R.sub.1, and R.sub.1 is a donor which is a substituted or unsubstituted 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine, and R.sub.2 is a donor which is substituted or unsubstituted, and is selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, a C.sub.2-C.sub.12 dialkyl amine, indolizine derivative, diphenylamine, and julolidine.
[0096] In Group B, the dyes are symmetrical, such as XanthCR-880. In Group C, the dyes are unsymmetrical. For instance, the donor at R.sub.1 could be 1-(thiophen-2-yl)piperidine and at R.sub.2 could be 1-(thieno[3,2-b]thiophen-2-yl)piperidine; or both R.sub.1 and R.sub.2 can be 1-(thiophen-2-yl)piperidine but one is substituted and the other is not.
[0097] The preferred structure of the donors is shown below.
1-(thiophen-2-yl)piperidine
[0098] ##STR00009##
wherein R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, and R.sub.11 are each independently selected from hydrogen, sulfonate, halogen, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbons, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an alkylether having 2-20 carbon atoms and 1 to 5 oxygen atoms; preferably the 1-(thiophen-2-yl)piperidine has 3 or fewer substituent, more preferably 1 substituent and most preferably no substituents, in other words, most preferably all of R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, and R.sub.11 are hydrogen.
[0099] The wavy line is globally used herein to refer to the location of the bond between the donor and the xanthene core structure.
1-(Thieno[3,2-b]thiophen-2-yl)piperidine
[0100] ##STR00010##
wherein R.sub.7, R.sub.8, R.sub.9, R.sub.10, and R.sub.11 are as described above. R.sub.12 and R.sub.13 are each independently selected from hydrogen, sulfonate, halogen, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms; preferably the 1-(thieno[3,2-b]thiophen-2-yl)piperidine has 3 or fewer substituents, more preferably 1 substituent and most preferably no substituents.
1-([2,2-Bithiophen]-5-yl)piperidine
[0101] ##STR00011##
[0102] wherein R.sub.7, R.sub.8, R.sub.9, R.sub.10, and R.sub.11 are as described above. R.sub.14 , R.sub.15, R.sub.16, and R.sub.17 are each independently selected from hydrogen, sulfonate, halogen, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms; preferably the 1-([2,2-bithiophen]-5-yl)piperidine has 3 or fewer substituents, more preferably 1 substituent and most preferably no substituents.
C.sub.2-C.sub.12 Dialkyl Amine
[0103] A C.sub.2-C.sub.12 dialkyl amine which is bonded to the xanthene core at the amine nitrogen, and is optionally substituted with 1 to 3 substituents selected from an alkenyl group having 2 to 10 carbon atoms, alkynyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, and a heterocyclic group having 3 to 16 carbon atoms; preferably the C.sub.2-C.sub.12 dialkyl amine has 1 substituent and most preferably no substituents.
Indolizin-3-yl
[0104] Indolizin-3-yl which is bonded to the xanthene core at the 3-position, and is substituted or unsubstituted. Preferably, the indolizine-3-yl donor is substituted with 1 to 3 substituents which are independently selected from halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, a heterocyclic group having 3 to 16 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms; more preferably the indolizine-3-yl donor is substituted has 3 or fewer substituent; even more preferably the indolizine-3-yl donor is substituted at the 1- and 2-positions with an alkyl group having 1 to 5 carbons and an aryl group having 6 to 10 carbon atoms; and even more preferably, the indolizine-3-yl donor is substituted at the 1-position with an alkyl group having 1 to 4 carbon atoms and at the 2-position with an aryl group having 6 to 8 carbon atoms; and most preferably, the indolizine donor is 1-methyl-2-phenylindolizin-3-yl.
Diphenylamine
[0105] The diphenylamine preferably has the following cationic structure (the corresponding nonionic structure is not shown):
##STR00012##
wherein R.sub.30, R.sub.31, R.sub.32, and R.sub.33 are independently selected from hydrogen, an alkyl group having 1 to 20 carbons, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, at least one combination of (R.sub.30 and R.sub.31) and (R.sub.32 and R.sub.33) together with N forming a substituted or unsubstituted pyrrolidine ring, a substituted or unsubstituted piperidine ring, a substituted or unsubstituted morpholine ring, a substituted or unsubstituted tetrahydropyridine ring or a substituted or unsubstituted cyclohexylamine ring.
Julolidine
[0106] Julolidine which preferably has the following cationic structure (the corresponding nonionic structure is not shown):
##STR00013##
which is optionally substituted with 1 to 3 substituents independently selected from a halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, an alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms, alkynyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, an aryl group having 6 to 10 carbon atoms, and a heterocyclic group having 3 to 16 carbon atoms. Preferably, the julolidine donor is not substituted or has one substituent.
[0107] The wavy line is globally used herein to refer to the location of the bond between the donor and the xanthene core structure.
[0108] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.
[0109] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
[0110] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.
[0111] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.
[0112] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. It is noted that the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.
[0113] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.
Definitions
[0114] As used herein, comprising is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms by, comprising, comprises, comprised of, including, includes, included, involving, involves, involved, and such as are used in their open, non-limiting sense and may be used interchangeably. Further, the term comprising is intended to include examples and aspects encompassed by the terms consisting essentially of and consisting of. Similarly, the term consisting essentially of is intended to include examples encompassed by the term consisting of. The transitional phrase consisting essentially of limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s) of the claimed invention.
[0115] As used in the specification and the appended claims, the singular forms a, an and the include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a solvent, a linear alkyl group, or an alcohol, include, but are not limited to, mixtures or combinations of two or more such solvents, linear alkyl groups, or alcohols, and the like.
[0116] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as about that particular value in addition to the value itself. For example, if the value 10 is disclosed, then about 10 is also disclosed. Ranges can be expressed herein as from about one particular value, and/or to about another particular value. Similarly, when values are expressed as approximations, by use of the antecedent about, it will be understood that the particular value forms a further aspect. For example, if the value about 10 is disclosed, then 10 is also disclosed.
[0117] When a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase x to y includes the range from x to y as well as the range greater than x and less than y.
[0118] It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of about 0.1% to 5% should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.
[0119] As used herein, the terms about, approximate, at or about, and substantially mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that about and at or about mean the nominal value indicated ?10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is about, approximate, or at or about whether or not expressly stated to be such. It is understood that where about, approximate, or at or about is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.
[0120] As used herein, the term effective amount refers to an amount that is sufficient to achieve the desired modification of a physical property of the composition or material. For example, an effective amount of a NIR dye for imaging of a biological sample refers to an amount that is sufficient to achieve the desired image quality. The specific level in terms of wt % or mol % in a composition required as an effective amount will depend upon a variety of factors including the absorption maxima of the dye, whether the biological sample is an isolated sample or is part of an organism in vivo, the identity of any pharmaceutically acceptable carrier, and the capabilities of the device used to measure the photoacoustic signal produced by the dye via non-radiative decay.
[0121] As used herein, the term donor' refers to an electron donor and the term acceptor refers to an electron acceptor in a donor-acceptor or donor-acceptor-donor dye. The terms donor and acceptor may be used to refer to the radicals in a donor-acceptor molecule (dye) or may he used to refer to separate chemical compounds that will form a donor-acceptor molecule once reacted together.
[0122] As used herein, the terms optional or optionally means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
[0123] Unless otherwise specified, pressures referred to herein are based on atmospheric pressure (i.e. one atmosphere).
[0124] NIR I as used herein refers to the region of the electromagnetic spectrum having wavelengths from about 700 to about 900 nm, while NIR II refers to that region having wavelengths from about 900 nm to about 1700 nm. In one aspect, the compounds disclosed herein emit fluorescence and/or absorb radiation in the NIR II region.
[0125] As used herein, fluorescence quantum yield (d)) refers to the ratio of photons absorbed to photons emitted through fluorescence.
[0126] Molar absorptivity, molar absorption coefficient, and extinction coefficient refer to how strongly a chemical compound absorbs light at a given wavelength. Molar absorptivity is an intrinsic property of the compound; however, this coefficient varies with wavelength and solvent. Molar absorptivity is typically expressed in terms of absorption at a particular wavelength, such as the maximum position in the absorption band. Units are typically given as L/mol.Math.cm or M.sup.?1.Math.cm.sup.?1. In one aspect, the disclosed NIR dyes have a high ? in the NIR II spectral region.
[0127] in one aspect, the NIR dye can have an absorption maximum in dimethyl sulfoxide (DMSO) at from about 800 nm to about 930 nm, or from about 830 nm, 840 nm, 850 nm, 860 nm, 870 nm, 880 nm, 890 nm or about 900 nm, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.
[0128] In another aspect, the NIR dye has a molar absorption coefficient of about 85,000 M.sup.?1.Math.cm.sup.?1 or greater, or of about 85,500 M.sup.?1.Math.cm.sup.?1, 86,000 M.sup.?1.Math.cm.sup.?1, 86,500 M.sup.?1.Math.cm.sup.?1, 87,000 M.sup.?1.Math.cm.sup.?1, 87,500 M.sup.?1.Math.cm.sup.?1, 88,000 M.sup.?1.Math.cm.sup.?1, 88,500 M.sup.?1.Math.cm.sup.?1, or about 88,900 M.sup.?1.Math.cm.sup.?1 or greater, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In still another aspect, the NIR dye has a fluorescence quantum yield of less than 5%, or less than 4%.
Chemical Groups and Substituents
[0129] As used herein, the term substituted is contemplated to include all permissible substituents of organic compounds while not materially affecting the basic and novel characteristic(s) of the claimed invention. Also, the terms substitution or substituted with include the implicit proviso that such substitution is in accordance with permitted valence of the substituted atom and the substituent, and that the substitution results in a stable compound, e.g., a compound that does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc.
[0130] The term alkyl as used herein is a linear, branched, or cyclic saturated hydrocarbon group of 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, and the like. The alkyl group can be cyclic (also referred to as carbocyclic) or acyclic. The alkyl group can be branched or unbranched. The alkyl group can also be substituted or unsubstituted. For example, the alkyl group can be substituted with 1 to 3 substituents independently selected from a halogen, sulfonate, hydroxy, amino, nitro, cyano, carboxy, a heterocyclic group having 3 to 16 carbon atoms, an alkylether having 2 to 20 carbon atoms and 1 to 5 oxygen atoms, and an alkoxy group having 1 to 20 carbon atoms. A lower alkyl group is an alkyl group containing from one to six (e.g., from one to four) carbon atoms. The term alkyl group can also be a Ci alkyl, C.sub.1-C.sub.2 alkyl, C.sub.1-C.sub.3 alkyl, C.sub.1-C.sub.4 alkyl, Ci-05 alkyl, C.sub.1-C.sub.6 alkyl, C.sub.1-C.sub.7 alkyl, C.sub.1-C.sub.8 alkyl, C.sub.1-C.sub.9 alkyl, C.sub.1-C.sub.10 alkyl, and the like up to and including a C.sub.1-C.sub.18 alkyl.
[0131] The term cycloalkyl as used herein is a non-aromatic carbon-based ring composed of three carbon atoms to ten carbon atoms. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, and the like.
[0132] The terms alkoxy and alkoxyl as used herein to refer to an alkyl or cycloalkyl group bonded through an ether linkage; that is, an alkoxy group can be defined as OA.sup.1 where A.sup.1 is alkyl, alkenyl or cycloalkyl as defined above.
[0133] The term aromatic group as used herein refers to a ring structure having cyclic clouds of delocalized ? electrons above and below the plane of the molecule, where the ? clouds contain (4n+2) ? electrons. A further discussion of aromaticity is found in Morrison and Boyd, Organic Chemistry, (5th Ed., 1987), Chapter 13, entitled Aromaticity, pages 477-497, incorporated herein by reference. The term aromatic group is inclusive of both aryl and heteroaryl groups.
[0134] The term aryl as used herein is a group that contains any carbon-based aromatic group including, but not limited to, benzene, naphthalene, phenyl, biphenyl, anthracene, pyrene, and the like. The aryl group can be substituted or unsubstituted. The aryl group can be substituted with one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, NH.sub.2, carboxylic acid, ester, ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol as described herein.
[0135] The term aldehyde as used herein is represented by the formula C(O)H. Throughout this specification C(O) is a short hand notation for a carbonyl group, i.e., C?O.
[0136] The terms amine or amino as used herein are represented by the formula NA.sup.1A.sup.2, where A.sup.1 and A.sup.2 can be, independently, hydrogen or alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein. A specific example of amino is NH.sub.2.
[0137] The term carboxylic acid as used herein is represented by the formula C(O)OH.
[0138] The term ester as used herein is represented by the formula OC(O)A.sup.1 or C(O)OA.sup.1, where A.sup.1 can be alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.
[0139] The term amide as used herein is represented by the formula N(A.sup.1)C(O)A.sup.2 or C(O)N(A.sup.2).sub.2, where A.sup.1 and A.sup.2 can be, independently, hydrogen, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.
[0140] The term ether as used herein is represented by the formula A.sup.1OA.sup.2, where A.sup.1 and A.sup.2 can be, independently, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group described herein.
[0141] The terms halo, halogen or halide, as used herein can be used interchangeably and refer to F, Cl, Br, or I.
[0142] The term heteroalkyl as used herein refers to an alkyl group containing at least one heteroatom. Suitable heteroatoms include, but are not limited to, O, N, Si, P and S, wherein the nitrogen, phosphorous and sulfur atoms are optionally oxidized, and the nitrogen heteroatom is optionally quaternized. heteroalkyls can be substituted as defined above for alkyl groups.
[0143] The terms heterocycle, heterocyclic or heterocyclyl, as used herein can be used interchangeably and refer to single and multi-cyclic aromatic (heteroaromatic) or non-aromatic ring (heteroalkyl) systems in which at least one of the ring members is other than carbon. heterocycle includes pyridine, pyrimidine, furan, thiophene, pyrrole, isoxazole, isothiazole, pyrazole, oxazole, thiazole, imidazole, oxazole, including, 1,2,3-oxadiazole, 1,2,5-oxadiazole and 1,3,4-oxadiazole, thiadiazole, including, 1,2,3-thiadiazole, 1,2,5-thiadiazole, and 1,3,4-thiadiazole, triazole, including, 1,2,3-triazole, 1,3,4-triazole, tetrazole, including 1,2,3,4-tetrazole and 1,2,4,5-tetrazole, pyridazine, pyrazine, triazine, including 1,2,4-triazine and 1,3,5-triazine, tetrazine, including 1,2,4,5-tetrazine, pyrrolidine, piperidine, piperazine, morpholine, azetidine, tetrahydropyran, tetrahydrofuran, dioxane, and the like. The heterocyclyl group can be a C.sub.2 heterocyclyl, C.sub.2-C.sub.3 heterocyclyl, C.sub.2-C.sub.4 heterocyclyl, C.sub.2-C.sub.6 heterocyclyl, C.sub.2-C.sub.6 heterocyclyl, C.sub.2-C.sub.7 heterocyclyl, C.sub.2-C.sub.8 heterocyclyl, C.sub.2-C.sub.9 heterocyclyl, C.sub.2-C.sub.10 heterocyclyl, C.sub.2-C.sub.11 heterocyclyl, and the like up to and including a C.sub.2-C.sub.18 heterocyclyl. For example, a C.sub.2 heterocyclyl comprises a group which has two carbon atoms and at least one heteroatom, including, but not limited to, aziridinyl, diazetidinyl, dihydrodiazetyl, oxiranyl, thiiranyl, and the like. Alternatively, for example, a Cs heterocyclyl comprises a group which has five carbon atoms and at least one heteroatom, including, but not limited to, piperidinyl, tetrahydropyranyl, tetrahydrothiopyranyl, diazepanyl, pyridinyl, and the like. It is understood that a heterocyclyl group may be bound either through a heteroatom in the ring, where chemically possible, or one of carbons comprising the heterocyclyl ring.
[0144] The term hydroxyl or hydroxy as used herein is represented by the formula OH.
[0145] The term nitro as used herein is represented by the formula NO.sub.2.
[0146] The term nitrile or cyano as used herein is represented by the formula CN.
[0147] As described herein, compounds of the invention may contain optionally substituted moieties. In general, the term substituted, whether preceded by the term optionally or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an optionally substituted group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this invention are preferably those that result in the formation of stable or chemically feasible compounds. It is also contemplated that, in certain aspects, unless expressly indicated to the contrary, individual substituents can be further optionally substituted (i.e., further substituted or unsubstituted).
[0148] The term radical, which as used in the specification and concluding claims, refers to a fragment, group, or substructure of a molecule described herein, regardless of how the molecule is prepared. For example, a 2,4-thiazolidinedione radical in a particular compound has the structure:
##STR00014##
regardless of whether thiazolidinedione is used to prepare the compound. In some embodiments the radical (for example an alkyl) can be further modified (i.e., substituted alkyl) by having bonded thereto one or more substituent radicals. The number of atoms in a given radical is not critical to the present invention unless it is indicated to the contrary elsewhere herein.
Pharmaceutically Acceptable Carriers and Biocompatibility
[0149] In various aspects, the dyes of the present disclosure can be given to a patient in a biocompatible composition in an amount effective to allow for PA or Fl analysis of a particular tissue, organ or system. As used herein, biocompatible refers to a material or composition that does not cause harm to living tissue. In one aspect, the MR dyes disclosed herein are biocompatible. Herein, the term biocompatible is used interchangeably with pharmaceutical or pharmaceutically acceptable. As used herein, pharmaceutically acceptable carriers means one or more of a pharmaceutically acceptable diluents, preservatives, antioxidants, solubilizers, emulsifiers, coloring agents, releasing agents, coating agents, sweetening, flavoring and perfuming agents, and adjuvants.
[0150] In another aspect, the present disclosure relates to pharmaceutical compositions include those suitable for parenteral administration, such as intravenous administration, although the most suitable route in any given case will depend on the particular host, and nature and severity of the conditions for which the NIR dyes ingredient are being administered.
[0151] In various aspects, the present disclosure also relates to a pharmaceutical composition comprising, a pharmaceutically acceptable carrier or diluent and an effective amount of the MR dye compounds of the present disclosure for bioimaging, a product of the method of making thereof, a pharmaceutically acceptable salt thereof, a hydrate thereof, a solvate thereof, a polymorph thereof, or a stereochemically isomeric form thereof. In a further aspect, the compounds of the present disclosure, a product of the method of snaking thereof, a pharmaceutically acceptable salt thereof, a hydrate thereof, a solvate thereof, a polymorph thereof, or a stereochemically isomeric form thereof, or any subgroup or combination thereof may be formulated into various pharmaceutical forms for administration purposes.
[0152] Pharmaceutical compositions of the present disclosure suitable for parenteral administration can include sterile aqueous or oleaginous solutions, suspensions, or dispersions. Furthermore, the compositions can be in the form of sterile powders for the extemporaneous preparation of such sterile injectable solutions or dispersions. In some aspects, the final injectable form is sterile and must be effectively fluid for use in a syringe. The pharmaceutical compositions should be stable under the conditions of manufacture and storage; thus, preferably should be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (e.g., glycerol, propylene glycol and liquid polyethylene glycol), vegetable oils, and suitable mixtures thereof.
[0153] Injectable solutions, for example, can be prepared in which the carrier comprises saline solution, such as a HEPES Buffered Saline or similar solutions.
[0154] As used herein, nontoxic refers to a material or composition that does not kill cells or organisms. In a further aspect, the NIR dyes disclosed herein are nontoxic.
Absorbance and Fluorescence of NIR Dyes
[0155] In terms of brightness, luminosity is dependent on the fluorophores' extinction coefficient (molar absorptivity) or ability to absorb light, and its quantum efficiency or effectiveness at transforming absorbed light into emitting luminescence. The NIR dyes themselves are not very fluorescent, but they are sufficiently fluorescent for brightness imaging. For instance, when the NIR dye binds to proteins, the protein becomes more easily detectable.
Methods for Making NIR Dyes
[0156] n an aspect, the disclosure relates to a method for making a NIR dyes, the method comprising: [0157] (a) Performing a C-H arylation reaction by combining a Donor and an Acceptor of Formula II with a catalyst in a solvent to form a reaction mixture,
##STR00015##
wherein R.sub.18 and R.sub.21 are individually selected from Cl, Br, I and OSO.sub.2R.sub.52 wherein R.sub.52 is a hydrogen or lower alkyl; [0158] wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are each independently selected from hydrogen or an alkyl group having 1 to 20 carbon atoms, or wherein one or more pair of R.sub.22 and R.sub.23, R.sub.24 and R.sub.25, R.sub.25 and R.sub.26, R.sub.26 and R.sub.27, R.sub.27 and R.sub.28, R.sub.28 and R.sub.29, together with the carbons they are attached form a saturated or unsaturated 6 membered ring; and [0159] wherein the Donor(s) is substituted or unsubstituted and comprises: (X) 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine; and (Y) 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, C.sub.2-C.sub.12 dialkyl amine, indolizine, diphenylamine, and julolidine, [0160] to thereby replace the groups at R.sub.18 and R.sub.21 with said Donor(s); [0161] (b) a ring opening reaction by transesterification with an alcohol to give the NIR dye of formula I
##STR00016##
wherein X is O, R.sub.3 and R.sub.4 are absent; [0162] R is selected from C(O)OH or an ester group represented by the formula C(O)OA.sup.1, wherein A.sup.1 is a linear or branched C.sub.1-C.sub.18 alkyl group; [0163] wherein R.sub.19, R.sub.20, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, and R.sub.29 are as described above; and [0164] R.sub.1 and R.sub.2 are both selected from one of the following Groups B and C:
Group B
[0165] Both R.sub.1 and R.sub.2 are the same donors and both are substituted or unsubstituted, and are selected from 1-(thiophen-2-yl)piperidine group, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, and 1-([2,2-bithiophen]-5-yl)piperidine; or
Group C
[0166] R.sub.1 and R.sub.2 are different donors and R.sub.1 is a donor which is substituted or unsubstituted and is a 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine or 1-([2,2-bithiophen]-5-yl)piperidine and R.sub.2 is a donor which is substituted or unsubstituted and is selected from 1-(thiophen-2-yl)piperidine, 1-(thieno[3,2-b]thiophen-2-yl)piperidine, 1-([2,2-bithiophen]-5-yl)piperidine, C.sub.2-C.sub.12 dialkyl amino, indolizine-3-yl, diphenylamino, and julolidinyl. In Group C, the dyes are unsymmetrical. For instance, the donor at R.sub.1 could be 1-(thiophen-2-yl)piperidine and at R.sub.2 could be 1-(thieno[3,2-b]thiophen-2-yl)piperidine; or both R.sub.1 and R.sub.2 can be 1-(thiophen-2-yl)piperidine but one is substituted and the other is not.
[0167] Preferably, the compound formed in step (a) has the following structure:
##STR00017##
[0168] In one aspect, the solvent in step (a) can be selected from N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMA), dimethylformamide (DMF), toluene, tetrahydrofuran (TRF), dioxane, or any combination thereof.
[0169] In one aspect, in step (a), the reaction mixture can be heated at a temperature from about 80? C. to about 150? C., or at about 80? C., 85? C., 90? C., 95? C., 100? C., 105? C., 110? C., 115? C., 120? C., 125? C., 130? C., 135? C., 140? C., 145? C., or about 150? C., or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In another aspect, the reaction mixture can be heated for from about 6 hours to about 30 hours, or for about 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, or about 24 hours, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In one aspect, step (a) can be conducted in an inert atmosphere such as, for example, nitrogen.
[0170] In one aspect, step (a) further includes admixing a catalyst with the compound of Formula II and the Donor. The catalyst can be Bis(triphenylphosphine)palladium(II) dichloride (PdCl.sub.2(PPh.sub.3).sub.2), Palladium(II)acetate (Pd(OAc).sub.2), Tris(dibenzylideneacetone)dipalladium(0) (Pd(dba).sub.3).Math.CHCl.sub.3, or any combination thereof. In a further aspect, from about 0.01 to about 0.1 moles of catalyst can be used per mole of compound of Formula II. Further in this aspect, about 0.01, 0.02, 0.03, 0.04 or about 0.05 moles of catalyst can be used, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.
[0171] In another aspect, step (a) further includes admixing a base with the compound of Formula II and the Donor. In still another aspect, the base can be potassium acetate (KOAc), sodium acetate (NaOAc), Cs.sub.2CO.sub.3, KO.sup.tBu, NaO.sup.tBu, K.sub.2CO.sub.3, Na.sub.2CO.sub.3, or any combination thereof. In one aspect, from about 2.0 moles to about 6.0 moles of base can be used per mole of compound of Formula II. Further in this aspect, about 2.0, 2.7, 3.0, 3.2, or about 3.3 moles to about 6.0, 5.5, 5.0, or about 4.5 moles of base can be used, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.
[0172] In still another aspect, step (a) further includes admixing a ligand with the compound of Formula II and the Donor compound. In a further aspect, the ligand can be triphenylphosphine (PPh.sub.3), Dicyclohexyl[2,4,6-tris(propan-2-yl)[1,1-biphenyl]-2-yl]phosphane (Xphos), 2,2-bis(diphenylphosphino)-1-1-binaphthyl (BINAP), (.sup.tBu).sub.2PMeHBF.sub.4, or any combination thereof. In an aspect, from about 1 to about 4 moles of ligand can be used per mole of catalyst, or about 1.5 to about 2.5, or about 2 moles of ligand per mole of catalyst can be used, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values.
[0173] In an aspect, in step (b), the alcohol used in the transesterification reaction is also a solvent or cosolvent. In an aspect, the alcohol is methanol, ethanol, propanol, isopropanol, or butyl alcohol. In an aspect, the reaction mixture is heated to reflux. In another aspect, the reaction mixture can be heated for from about 6 hours to about 24 hours, or for about 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or about 24 hours, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In one aspect, step (b) can be conducted in an inert atmosphere such as, for example, nitrogen.
[0174] As noted above, the donors can be symmetrical or unsymmetrical in a D-A-D designed molecule. For symmetrical dyes, such as XanthCR-880, the donor is combined with the acceptor using twice the moles of the donor when compared to the moles of acceptor. On the other hand, an NIR dye having an unsymmetrical D1-A-D2 design could be prepared by essentially the same synthesis except that some of the D1 reactants are replaced with D2 reactants, such that: total moles (D1+D2) is twice the moles of A. In addition, NIR dyes having R.sub.1=H could be made by starting with an acceptor having only one leaving group and using equal moles of acceptor and donor.
[0175] Also disclosed are NIR dyes produced by the disclosed methods.
Compositions, Methods, and Devices Using the NIR Dyes
[0176] In one aspect, disclosed herein is a composition including an NIR dye disclosed herein which optionally has a carrier. In a further aspect, the carrier can be a pharmaceutically-acceptable carrier. in still another aspect, the compositions can be biocompatible and/or nontoxic.
[0177] Also disclosed herein are methods for imaging a biological sample. In one aspect, the method includes the steps of (a) contacting the biological sample with a disclosed composition; (b) exposing the biological sample and the composition to NIR radiation; and (c) observing PA emission in the biological sample. In a further aspect, the biological sample includes an organelle, a cell, a tissue, an organ, or any combination thereof.
[0178] Other potential applications include composites comprising the dyes in a polymer matrix for commodity items such as eye glasses, night vision glasses or smart glasses, sensors, laser, and optoelectronic materials for electrical devices.
[0179] Now having described the aspects a the present disclosure, in general, the following Examples describe some additional aspects of the present disclosure. While aspects of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure.
EXAMPLES
[0180] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated and are intended to be purely exemplary of the disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in 20? C.-22? C. or is at ambient temperature; and pressure is at or near atmospheric.
[0181] All chemicals and solvents were purchased from commercial suppliers and used without further purification unless other-wise specified. .sup.1H NMR (500 MHz) and .sup.13C NMR (500 MHz) spectra were recorded in deuterated solvents on a Bruker ADVANCE 500 NMR Spectrometer. J values are expressed in Hz and quoted chemical shifts are in ppm downfield from tetramethylsilane (TMS) reference using the residual protonated solvents as an internal standard. The signals have been designated as follows: s (singlet), d (doublet), t (triplet), m (multiplets). All the .sup.13C NMR are proton decoupled. High resolution mass spectra (HRMS) were determined on Broker-micrOTOF-Q II Mass Spectrometer. Concentrations are given in ?M. Absorption spectra were acquired using a Cary 5000 UV-Vis-NIR spectrophotometer in a 1 cm quartz cell.
[0182] Fluorescence spectra were acquired using a custom-built setup with discrete excitation wavelengths ranging from 226 nm to 1059 nm with a temperature range from 4.2 K to 300 K using a liquid He bath cryostat. Alternatively, a Horiba QuantaMaster 8075-21 spectrofluorometer with xenon lamp excitation and liquid nitrogen cooled indium gallium arsenide solid state detector could be used. 882 mu excitation was chosen to coincide with a Xe emission peak.
[0183] Photoacoustic A imaging was performed on an iThera Medical MSOT inVision 128 tomographer.
Example 1: Synthesis of XanthCR-880 (1-{5-[(3E)-9-[2-(Ethoxycarbonyl)phenyl]-6-[5-(piperidin-1-yl)thiophen-2-yl]-3H-xanthen-3-ylidene]-2,5-dihydrothiophen-2-ylidene}-1?5-piperidin-1-ylium chloride)
[0184] As shown in
[0185] Treatment of Compound (3) with TFA resulted in the opened form; however, to maintain the ring-opened form, Compound (3) was esterified with ethanol to give XanthCR-880 in 62% yield. Compound (3) (385.0 mg, 0.6 mmol) was transferred to a 250 mL two-neck round bottom flask and flushed with nitrogen for 10 min. 1,2-dichloroethane (12 mL) and POCl.sub.3 (1.68 mL) were added to the flask and the reaction was refluxed in an oil bath for 24 h. The reaction mixture was cooled to room temperature and concentrated under reduced pressure to give a green solid, which was used in the next step without further purification. The reaction mixture was thoroughly flushed with nitrogen for 10 min, followed by the addition of dry ethanol (10 mL) and refluxed in an oil bath for 24 h. The reaction mixture was concentrated under reduced pressure and the crude product was purified by column chromatography on silica gel (DCM: ethanol v/v 90:10) to give a green solid. The solid was dissolved in DCM (50 mL), washed with brine (3?100 mL) and 2.0 M HCl solution (3?100 mL), and dried over sodium sulfate, filtered, and concentrated under reduced pressure to give 250 mg of XanthCR-880 as a green solid in 62% overall yield. .sup.1H NMR (500 MHz, CDCl.sub.3): ? (ppm) 8.32 (d, J=7.6 Hz, 1H), 7.82 (s, 3H), 7.75 (t, J=7.4 Hz, 1H), 7.50 (d, J=8.6 Hz, 2H), 7.41 7.31 (m, 3H), 6.98 (d, J=8.6 Hz, 2H), 6.39 (s, 2H), 4.07 (dd, J=13.4, 6.6 Hz, 2H), 3.49 (s, 8H), 1.82 1.68 (m, 12H), 1.07 (t, J=6.7 Hz, 3H). .sup.13C {1H} NMR (126 MHz, CDCl.sub.3): ? (ppm) 167.4, 165.3, 156.4, 156.1, 145.5, 135.5, 133.8, 133.4, 131.8, 130.7, 129.2, 125.1, 123.9, 121.2, 109.0, 107.6, 61.9, 52.2, 25.5, 23.8, 14.1. HRMS (ESI) m/z: [M]+ Calcd for C40H39N2O3S2+659.2396; found 659.2393.
[0186] The closed (Compound 3) and opened (XanthCR-880) forms of the dye can be differentiated by the shift in the resonance for the proton ortho to the carbonyl group on the spirolactone moiety using .sup.1H NMR; this proton's peak shifts downfield (?8.32 ppm) in the opened form compared to the closed form (?8.03 ppm). Additionally, the chemical shift of the
[0187] C-9 carbon is different between the open and closed forms.
[0188] The IR spectrums of the closed (Compound 3) and opened (XanthCR-880) forms of the dye are very distinct. The IR spectrums were obtained in dichloromethane (DCM) and dimethyl sulfoxide (DMSO) (
[0189] Attempts to determine the fluorescent quantum yield showed that XanthCR-880 had sufficient fluorescence for brightness imaging.
[0190] The XanthCR-880 dye was also shown to have excellent stability. The stability of XanthCR-880 dye was tested against glutathione, which is a potential reducing agent in biological media. The XanthCR-880 dye (17 ?M) was prepared in 40% DMSO/60% PBS solution with 10 mM reduced glutathione and evaluated the change in the maximum absorption at 880 nm. The 10 mM concentration of reduced glutathione was selected to reflect the highest reported levels found in the body (i.e., liver). There was no change observed in the absorbance of the dye after 30 min. See
[0191] Furthermore, the stability of XanthCR-880 was evaluated in the presence of esterases, which can potentially hydrolyze the ethyl ester, resulting in the closed PA-inactive form (Compound 3). When XanthCR-880 was incubated at room temperature for 30 min with porcine liver esterase, no significant change in the absorbance was noted (
[0192] It is common for the ?.sub.PA value to differ slightly from the corresponding ?.sub.abs based on empirical observation. Without being bound to theory, it was believed that since the appearance of both PA spectra feature sharp peaks characteristic of xanthene-based dyes, the XanthCR-880 exists predominantly in a non-aggregated state under these conditions. This is an important consideration because aggregates are associated with weaker PA signals owing to significant broadening of the absorbance band and a corresponding decrease of the molar absorptivity.
[0193] Next, it was established that there was a linear relationship between dye concentration and the PA signal up to the highest concentration tested (2.0 ?M) and a limit of detection of 0.36 ?M in ethanol (
[0194] Ideally PA contrast agents are photostable. When PA contrast agent are used in studies, they may be subjected to multiple imaging sessions, and as such are ideally resistant to photobleaching. When XanthCR-880 was continuously irradiated at its ?PA for 60 min, it was found that the PA signal decreased by only 45%, indicating that XanthCR-880 is exceptionally photostable (
[0195] Spectral unmixing is a technique employed to isolate the signal of a PA contrast agent from that of other PA-active molecules such as hemoglobin found in blood. It was shown that this is possible using measurements with PA-active molecules in known concentrations and having well-defined PA spectrums. Typically, when newly developed dyes are tested for their PA properties, they are overlaid with a tissue mimicking phantom casted from agar containing 10% milk by volume. While this setup is efficient at scattering the incident light to provide even illumination of a sample, it lacks strong optical absorbers found in tissue that can attenuate light. As such, a better challenge to test the maximum attainable imaging depth was developed.
[0196] In conclusion, a new xanthene-based dye was developed using the D-A-D strategy with a thienylpiperidine unit, which is a strong donor, and the xanthene core as the acceptor. absX and Xem in the NIR I region was achieved and established that the dye is highly photostable. Furthermore, the dye is resistant to high concentration of glutathione and esterases, suggesting that it would be stable in biological environment. XanthCR-880 gave a weak emission signal; however, the PA signal was very intense and the ?.sub.PA is in the NIR region in organic and aqueous media. XanthCR-880 is compatible with multiple PA imaging systems and produced good PA signals even at depth of 4 cm in tissue. This is the longest wavelength xanthene-based PA dye to date.
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