Dinaphthothiophene compounds

Abstract

The present invention generally relates to various dinaphthothiophene compounds and processes for preparing these compounds.

Claims

1. A dinaphthothiophene compound of Formula III: ##STR00030## wherein R.sub.3 is hydroxy, substituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; R.sub.4 is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; and n is 1 or 2.

2. The compound of claim 1 wherein R.sub.3 is hydroxy, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

3. The compound of claim 1 wherein R.sub.3 is hydroxy, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

4. The compound of claim 1 wherein R.sub.3 is hydroxy, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

5. The compound of claim 1 wherein R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

6. The compound of claim 1 wherein R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

7. The compound of claim 1 wherein R.sub.4 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

8. A dinaphthothiophene compound of Formula III: ##STR00031## wherein R.sub.3 is hydroxy, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl; R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl; and n is 1 or 2.

9. The compound of claim 8 wherein R.sub.3 is hydroxy, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl and R.sub.4 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

10. A dinaphthothiophene compound of Formula III: ##STR00032## wherein R.sub.3 is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; R.sub.4 is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; and n is 1 or 2, and wherein R.sub.3 and R.sub.4 are different.

11. The compound of claim 10 wherein R.sub.3 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

12. The compound of claim 10 wherein R.sub.3 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

13. The compound of claim 10 wherein R.sub.3 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

14. The compound of claim 10 wherein R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

15. The compound of claim 10 wherein R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl.

16. The compound of claim 10 wherein R.sub.4 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

17. The compound of claim 10 wherein R.sub.3 is methoxy, ethoxy, propoxy, or trifluoromethyl and R.sub.4 is hydrogen, methyl, ethyl, propyl, butyl, or trifluoromethyl.

18. A dinaphthothiophene compound of Formula III: ##STR00033## wherein R.sub.3 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl; R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl; and n is 1 or 2, and wherein R.sub.3 and R.sub.4 are different.

19. A process for preparing the dinaphthothiophene compound of claim 1, comprising oxidizing a dinaphthothiophene compound of Formula III-A: ##STR00034## to form the dinaphthothiophene compound of Formula III, wherein R.sub.3 and R.sub.4 are as defined for Formula III.

20. The process of claim 19 further comprising: formylating 3,4-dibromothiophene to form 4-bromothiophene-3-carbaldehyde; reacting, in the presence of a catalyst comprising palladium, a base, and organic solvent, 4-bromothiophene-3-carbaldehyde with a phenylethenyl boronic compound of Formula C-1: ##STR00035## to form a 3-formyl-4-styrylthiophene compound of Formula C-2: ##STR00036## reacting, in the presence of sodium hydride, the 3-formyl-4-styrylthiophene compound of Formula C-2 with a 4-substituted phosphonic acid diethyl ester compound of Formula C-3: ##STR00037## to form a compound of Formula C-4: ##STR00038## irradiating the compound of Formula C-4 with UV light in the presence of iodine and propylene oxide to form the dinaphthothiophene compound of Formula III-A: ##STR00039## wherein R.sub.3 and R.sub.4 are as defined for Formula III.

21. A process for preparing the dinaphthothiophene compound of claim 10, comprising oxidizing a dinaphthothiophene compound of Formula III-A: ##STR00040## to form the dinaphthothiophene compound of Formula III, wherein R.sub.3 and R.sub.4 are as defined for Formula III.

22. The process of claim 21 further comprising: formylating 3,4-dibromothiophene to form 4-bromothiophene-3-carbaldehyde; reacting, in the presence of a catalyst comprising palladium, a base, and organic solvent, 4-bromothiophene-3-carbaldehyde with a phenylethenyl boronic compound of Formula C-1: ##STR00041## to form a 3-formyl-4-styrylthiophene compound of Formula C-2: ##STR00042## reacting, in the presence of sodium hydride, the 3-formyl-4-styrylthiophene compound of Formula C-2 with a 4-substituted phosphonic acid diethyl ester compound of Formula C-3: ##STR00043## to form a compound of Formula C-4: ##STR00044## irradiating the compound of Formula C-4 with UV light in the presence of iodine and propylene oxide to form the dinaphthothiophene compound of Formula III-A: ##STR00045## wherein R.sub.3 and R.sub.4 are as defined for Formula III.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention generally relates to substituted derivatives of DNT-2112, DNT-1212, and DNT-1221 and processes to synthesize these compounds starting from mono- and dibromine-substituted thiophenes.

(2) ##STR00006##
Each of these routes involves only 3-4 steps in total, and contains the potential for the symmetric and asymmetric introduction of a wide variety of functional groups. Consequently, these processes can be used to synthesize a wide variety of functionalized dinaphthothiophenes.

(3) The derivatives of three different classes of thiophenes (dinaphtho[2,1-b:1,2-d]thiophene, dinaphtho[1,2-b;1,2-d]thiophene, and dinaphtho[1,2-b:2,1-d]thiophene) were created by three different processes. Each route followed the same general strategy, beginning with two styrene groups being sequentially added to a mono- or dibrominated thiophene by either Suzuki coupling or Horner-Wadsworth-Emmons reaction. Once the thiophene was doubly substituted with styrene units, a photocyclization reaction with iodine as an oxidative catalyst was used to create the final dinaphthothiophene structure. In contrast to other synthetic routes, asymmetrically substituted functional groups have been incorporated into the synthesis of the DNT structure itself. Methoxy, trifluoromethyl, and methyl functional groups were used to create substituted DNTs. These three groups were chosen for their differences in electronegativity, which could be used to tune the electronic properties of DNTs. Whereas only symmetrically-substituted DNTs had been synthesized before, now a wide variety of asymmetrically-substituted DNTs can be easily made and tuned for use in organic semiconductors and chiral 1,1-binaphthyl catalysts.

(4) Various dinaphthothiophene compounds of the present invention include compounds of Formula I (i.e., derivatives of DNT-1212):

(5) ##STR00007##
wherein R.sub.1 is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; R.sub.2 is hydrogen, hydroxy, or substituted or unsubstituted C.sub.1-C.sub.20 alkyl; and n is 0, 1, or 2.

(6) In various embodiments, R.sub.1 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In some embodiments, R.sub.1 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In certain embodiments, R.sub.1 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

(7) In various embodiments, R.sub.2 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In some embodiments, R.sub.2 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In certain embodiments, R.sub.2 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

(8) In some embodiments, R.sub.1 and R.sub.2 are different.

(9) Various processes of the present invention are directed to preparing the dinaphthothiophene compounds of Formula I. In general, these processes comprise one of more of the following steps of:

(10) reacting, in the presence of a catalyst comprising palladium, a base, and organic solvent, 2,4-dibromothiophene with a phenylethenyl boronic acid compound of Formula A-1:

(11) ##STR00008##
to form a 4-bromo-2-styrylthiophene compound of Formula A-2:

(12) ##STR00009##

(13) reacting, in the presence of a catalyst comprising palladium, a base, and organic solvent, the 4-bromo-2-styrylthiophene compound of Formula A-2 with a phenylethenyl boronic acid compound of Formula A-3:

(14) ##STR00010##
to form a 2,4-distryrylthiophene compound of Formula A-4:

(15) ##STR00011##

(16) irradiating the compound of Formula A-4 with UV light in the presence of iodine and propylene oxide to form a dinaphthothiophene compound of Formula I-A:

(17) ##STR00012##
wherein R.sub.1, and R.sub.2 are as defined above for Formula I. A further oxidation step can be performed to yield the compounds of Formula I-B:

(18) ##STR00013##
where R.sub.1, and R.sub.2 are as defined above for Formula I and n is 1 or 2. The oxidation can be performed using an oxidant such as meta-chloroperoxybenzoic acid.

(19) Other dinaphthothiophene compounds of the present invention include compounds of Formula II (i.e., derivatives of DNT-2112):

(20) ##STR00014##
wherein R is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; and n is 0, 1, or 2.

(21) In various embodiments, R is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In some embodiments, R is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In certain embodiments, R is hydrogen, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, or trifluoromethyl. In some embodiments, R is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

(22) Further processes of the present invention are directed to preparing the dinaphthothiophene compounds of Formula II. In general, these processes comprise the steps of:

(23) reacting 2-bromthiophene with trans-2-(4-phenyl)vinylboronic acid in the presence of a catalyst comprising palladium, a base, and organic solvent to form (E)-2-styrylthiophene;

(24) formylating (E)-2-styrylthiophene to form (E)-5-styrylthiophene-2-carbaldehyde;

(25) reacting, in the presence of sodium hydride, (E)-5-styrylthiophene-2-carbaldehyde with a 4-substituted phosphonic acid diethyl ester compound of Formula B-1:

(26) ##STR00015##
to form a compound of Formula B-2:

(27) ##STR00016##

(28) irradiating the compound of Formula B-2 with UV light in the presence of iodine and propylene oxide to form a dinaphthothiophene compound of Formula II-A:

(29) ##STR00017##
wherein R is as defined for Formula II. A further oxidation step can be performed to yield the compounds of Formula II-B:

(30) ##STR00018##
wherein R is as defined for Formula II and n is 1 or 2. The oxidation can be performed using an oxidant such as meta-chloroperoxybenzoic acid.

(31) Still further dinaphthothiophene compounds of the present invention include compounds of Formula III (i.e., derivatives of DNT-1221):

(32) ##STR00019##
wherein R.sub.3 is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl and R.sub.4 is hydrogen, hydroxy, substituted or unsubstituted C.sub.1-C.sub.20 alkyl, or substituted or unsubstituted aryl; and n is 0, 1, or 2.

(33) In various embodiments, R.sub.3 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In some embodiments, R.sub.3 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In certain embodiments, R.sub.3 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

(34) In various embodiments, R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.20 alkoxy, C.sub.1-C.sub.20 haloalkyl, C.sub.1-C.sub.20 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In some embodiments, R.sub.4 is hydrogen, hydroxy, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.1-C.sub.10 haloalkyl, C.sub.1-C.sub.10 haloalkoxy, aryl, alkyl-substituted aryl, halo-substituted aryl, or hydroxy-substituted aryl. In certain embodiments, R.sub.4 is hydrogen, hydroxy, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, trifluoromethyl, phenyl, hydroxyphenyl, ethylphenyl, carboxyphenyl, naphthyl, anthracenyl, biphenyl, tolyl, cumyl, styryl, ortho-xylyl, meta-xylyl, para-xylyl, fluorophenyl, chlorophenyl, bromobenzyl, or iodobenzyl.

(35) In various embodiments, R.sub.3 and R.sub.4 are different.

(36) Further processes of the present invention are directed to preparing the dinaphthothiophene compounds of Formula III. In general, these processes comprise the steps of:

(37) formylating 3,4-dibromothiophene to form 4-bromothiophene-3-carbaldehyde;

(38) reacting, in the presence of a catalyst comprising palladium, a base, and organic solvent, 4-bromothiophene-3-carbaldehyde with a phenylethenyl boronic compound of Formula C-1:

(39) ##STR00020##
to form a 3-formyl-4-styrylthiophene compound of Formula C-2:

(40) ##STR00021##

(41) reacting, in the presence of sodium hydride, the 3-formyl-4-styrylthiophene compound of Formula C-2 with a 4-substituted phosphonic acid diethyl ester compound of Formula C-3:

(42) ##STR00022##
to form a compound of Formula C-4:

(43) ##STR00023##

(44) irradiating the compound of Formula C-4 with UV light in the presence of iodine and propylene oxide to form the dinaphthothiophene compound of Formula III-A:

(45) ##STR00024##
wherein R.sub.3 and R.sub.4 are as defined for Formula III above. A further oxidation step can be performed to yield the compounds of Formula III-B:

(46) ##STR00025##
wherein R.sub.3 and R.sub.4 are as defined for Formula III above and n is 1 or 2. The oxidation can be performed using an oxidant such as meta-chloroperoxybenzoic acid.

(47) Unless otherwise indicated, the alkyl groups described herein are preferably lower alkyl groups containing from 1 to 20 carbon atoms in the principal chain. They may be straight or branched chain or cyclic. Also, unless otherwise indicated, the substituted alkyl groups described herein can contain saturated or unsaturated and branched or unbranched carbon chains having from 1 to 20 carbon atoms in the principal chain.

EXAMPLES

(48) The following non-limiting examples are provided to further illustrate the present invention.

Example 1. Synthesis of Dinaphtho[1,2-b;1,2-d]thiophenes

(49) ##STR00026##

(50) DNT-1212 derivatives were synthesized using the path shown in Scheme 1. This synthetic path used for the synthesis of asymmetrically substituted DNT-1212 derivatives began with 2,4-dibromothiophene. The bromine in the 2-position is preferentially substituted over the 4-position in carbon-carbon coupling reactions to give an asymmetric product.[27-32]. Therefore, a Suzuki-Miyaura reaction with one equivalent of [(E)-2-phenylethenyl]boronic acid or [(E)-2-[4-(methyl)phenyl]ethenyl]boronic acid was performed to add the first styrene unit to give 4-bromo-2-styrylthiophenes 1 and 2 (Table 1). A second Suzuki-Miyaura reaction was used to add a second styryl group in the 4-position. This second coupling was successful with 4-substituted styrylboronic acids to give 2,4-distyrylthiophenes 3-8 (Table 1). These Suzuki-Miyaura couplings gave yields anywhere from 10% to 81% depending on the substituent on the boronic acid. Reactions were performed at temperatures ranging from 55 C. to 95 C.; however, no significant change in yield was noticed. Unsubstituted styrylboronic acids gave the highest yields, followed by trifluoromethyl-substituted styrylboronic acids. Methoxy-substituted boronic acids gave the lowest yields. In the next step of this synthetic route, 2,4-distyrylthiophenes 3-8 were irradiated with UVC light in the presence of iodine and propylene oxide to fuse the rings, giving DNTs 9-14 (Table 2). This photoreaction proceeds by an oxidative mechanism: first, a photoinduced electrocyclization to create the CC bond, followed by an oxidative dehydrogenation catalyzed by iodine to regain aromaticity.[33] The photocyclization of 2,4-distyrylthiophenes gave yields of 20-31%, with the exception of 4. The photocyclization resulting in compound 4 gave a higher yield of 66%, in contrast to most other reactions performed involving methoxy-substituted reactants, which had significantly lower yields on average than those involving different substituents.

(51) TABLE-US-00001 TABLE 1 Suzuki-Miyaura Reactions. Water Bromo- Equiv. Temp. (% of Yield Entry thiophene Product RB(OH).sub.2 ( C.) solvent) (%) 1 2,4-dibromo- 1 1.1 95 11 81 thiophene 2 2,4-dibromo- 2 1.1 90 20 29 thiophene 3 1 3 1.2 80 17 46 4 1 4 1.1 85 17 10 5 1 5 1.2 55 17 48 6 2 6 1.2 80 20 36 7 2 7 1.1 75 17 30 8 2 8 1.1 75 17 31 9 2-Bromo- 15 1.2 80 11 78 thiophene

(52) TABLE-US-00002 TABLE 2 2,4-Distyrylthiophene Cyclization. Entry Distyrylthiophene Product Time (days) Yield (%) 1 3 9 0.8 24 2 4 10 0.6 66 3 5 11 1.9 24 4 6 12 0.8 31 5 7 13 0.8 20 6 8 14 0.7 28

(53) The 4-substituted trans-2-(phenylethenyl)boronic acids used in the Suzuki-Miyaura coupling step often underwent self-coupling rather than coupling with the bromothiophene. This created a side product which was detected by GCMS, with an m/z dependent on the boronic acid used. For example, Suzuki reactions involving unsubstituted styrylboronic acids in Table 1 (Entries 1, 3, and 6), gave a product with a m/z of 206 and was believed to be 1,4-diphenyl-1,3-butadiene. The purification of the desired products was complicated by the presence of these self-coupled byproducts, especially in the case of 7. Propylene oxide was added to all photocyclizations to quench the HI resulting from the reaction. In every photoreaction, care was taken not to irradiate the solution past completion, which would result in both a decreased yield and a white precipitate that was insoluble in organic solvents. In the absence of iodine, most photoreactions still occurred; however, they proceeded more slowly. In the synthesis of both DNT-1221 derivatives and DNT-2112 derivatives, reactions involving a methoxy substituent gave lower yields than those involving other substituents.

Example 2. Synthesis of Dinaphtho[1,2-b;1,2-d]thiophenes

(54) ##STR00027##

(55) DNT-2112 derivatives 20-22 were created using the synthetic route shown in Scheme 2. First, 2-bromothiophene was coupled with a trans-2-(4-Phenyl)vinylboronic acid using a Suzuki-Miyaura coupling to create compound 15 in 76% yield. [34] The 5-position of the thiophene ring was then formylated using n-Butyllithium and DMF, giving compound 16 in 36% yield. [35,36] The 5-position is preferentially formylated due to its relatively low pK.sub.a (33) compared to the 3 or 4 positions (39) resulting from its location next to the sulfur in the thiophene ring.[37] A Horner-Wadsworth-Emmons reaction using a 4-substituted phosphonic acid diethyl ester was used to add a second styryl group to the other side of the thiophene ring (Table 3) to create 2,5-distyrylthiophenes 17-19. The methoxy-substituted phosphonic acid diethyl ester gave a 14% yield that was significantly lower than the methyl and trifluoromethyl-substituted phosphonic esters, which gave yields of 58% and 76%, respectively. The DNTs 20-22 were created via the same oxidative photocyclization used in the synthesis of DNTs 9-14 (Table 4).

(56) TABLE-US-00003 TABLE 3 Horner-Wadsworth-Emmons Reaction with 2-Formyl-5-Styrylthiophene. Phosphonic Equiv. Entry Aldehyde Product Equiv. Ester NaH Yield (%) 1 16 17 1.3 5.5 58 2 16 18 1.9 3.3 14 3 16 19 1.2 4.7 76

(57) TABLE-US-00004 TABLE 4 2,5-Distyrylthiophene Cyclization. Entry Distyrylthiophene Product Time (days) Yield (%) 1 17 20 6 1 2 18 21 27 <1% 3 19 22 1.5 29

(58) The Horner-Wadsworth-Emmons reaction of 16 to yield 2,5-distyrylthiophenes 17-19 gave unreliable yields. Different variables, such as molar equivalents of sodium hydride and temperature during reagent addition, were changed with no consistent improvement in yield. The Horner-Wadsworth-Emmons reaction to give 18 (14% yield) and the subsequent photocyclization to give 21 (<1% yield) gave significantly lower yields than the reactions to produce 17 and 19. The photocyclization of 18 did not yield enough 21 to completely characterize, though it was detected by GCMS. This follows the trend seen in Table 1 (Entries 4 and 7) and Table 2 (Entry 5) where the Suzuki coupling and photocyclization of reactants containing the methoxy group gave lower yields. In addition, 2,5-distyrylthiophenes gave lower photocyclization yields than other distyrylthiophenes. Since DNT-2112 is known to adopt a twisted conformation, these lower yields are likely due to sterics hindering the cyclization of 2,5-distyrylthiophene into the planar shape of other fused thiophene structures.[13]

Example 3. Synthesis of Dinaphtho[1,2-b;1,2-d]thiophenes

(59) ##STR00028##

(60) DNT-1221 derivatives 32-36 were synthesized using the route shown in Scheme 3. Formylation with n-butyllithium and DMF was used to convert 3,4-dibromothiophene to 3-bromothiophene-4-carbaldehyde 23 in 77% yield.[38,39] Suzuki-Miyaura coupling was then used to add the first styryl group to one side of the thiophene ring to give 3-formyl-4-styrylthiophenes 24-26 in 10-77% yield (Table 5), from which asymmetric distyrylthiophenes could easily be synthesized. The trifluoromethyl-substituted styrylboronic acid gave the highest yields. A Horner-Wadsworth-Emmons reaction was used to add the second substituted styryl group to the other side of the thiophene ring (Table 6), creating 3,4-distyrylthiophenes 27-31 in yields from 16-95%. The CF.sub.3-substituted benzylphosphonic esters used in the creation of 29 and 30 gave higher yields compared to those with other substituents. The Suzuki-Miyaura coupling was performed before the Horner-Wadsworth-Emmons reaction in this route because the 1,4-diphenyl-1,3-butadiene byproducts formed from the Suzuki-Miyaura reaction were easier to separate from the more polar 3-formyl-4-styrylthiophenes than from 3,4-distyrylthiophenes. An oxidative photocyclization was then used in the same manner as the previous routes to fuse the rings together to give DNT-1221 derivatives 32-36 in yields of 6-20% (Table 7).

(61) TABLE-US-00005 TABLE 5 Suzuki-Miyaura Reaction with 3-Bromo-4-Formylthiophene Equiv. Temp. Entry Bromothiophene Product R-B(OH).sub.2 ( C.) Yield (%) 1 23 24 1.2 95 77 2 23 25 1.5 70 46 3 23 26 1.2 86 86

(62) TABLE-US-00006 TABLE 6 Horner-Wadsworth-Emmons Reaction with 3-Formyl-4-Styrylthiophene Entry Aldehyde Product Equiv. Phosphonic Ester Yield (%) 1 24 27 1.5 16 2 24 28 1.2 21 3 24 29 1.5 95 4 25 30 1.5 32 5 26 31 1.0 40

(63) TABLE-US-00007 TABLE 7 3,4-Distyrylthiophene Cyclization Entry Distyrylthiophene Product Time (hours) Yield (%) 1 27 32 8 7 2 28 33 6.5 20 3 29 34 7.5 18 4 30 35 5 9 5 31 36 3.5 6

(64) A side product of the photoreaction of 27-31 is suspected to form by the ring closure of the thiophene ring as shown in Scheme 4, forming side products 37-41. The side product for Table 7, Entry 1 (37) was analyzed by GCMS and shown to have an m/z of 300, corresponding to the loss of H.sub.2 by the oxidative dehydrocyclization mechanism. Solvents such as toluene, hexanes, and a mixture of dichloromethane and hexanes were tried in the photocyclization reaction, but there was no significant change in the product ratios. Preparative TLC was used to separate the photocyclization reaction products.

(65) ##STR00029##

(66) When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles a, an, the and said are intended to mean that there are one or more of the elements. The terms comprising, including and having are intended to be inclusive and mean that there may be additional elements other than the listed elements.

(67) In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

(68) As various changes could be made in the above compositions and processes without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

(69) Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.

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