Method for synthesizing iodo- or astatoarenes using diaryliodonium salts

Abstract

The present invention concerns a method of synthesizing a iodo- or astatoarene comprising the reaction of a diaryliodonium compound with a iodide or astatide salt, respectively. The invention also relates to said iodo- or astatoarene and diaryliodonium compound as such. The invention also concerns a method of synthesizing a iodo- or astatolabelled biomolecule and/or vector using said iodo- or astatoarene.

Claims

1. A method of synthesizing an astatoarene comprising reacting a diaryliodonium compound with an astatide salt, wherein the diaryliodonium compound is of formula (II): ##STR00050## wherein: Ar.sub.1 and Ar.sub.2, independently of each other, are chosen from: (C.sub.6-C.sub.10)aryl and heteroaryl groups, said aryl and heteroaryl groups being substituted with one or several substituents selected from: (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkynyl, optionally substituted heteroaryl, halogen, NO.sub.2, CN, N.sub.3, CF.sub.3, ORa, COORb, C(O)R.sub.8, NCO, NCS, N(Ra)COORb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)Rb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)(C.sub.1-C.sub.6)alkylene-Rb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)(C.sub.1-C.sub.6)alkylene-C(O)ORb and maleimidyl, said (C.sub.1-C.sub.6)alkyl group being optionally substituted with one or several substituents selected from N.sub.3, OH, OCH.sub.3, CF.sub.3, OCH.sub.2O(C.sub.1-C.sub.6)alkyl, O(C.sub.1-C.sub.6)alkenyl and O(C.sub.1-C.sub.6)alkylene-(C.sub.6-C.sub.10)aryl; Ra is H or (C.sub.1-C.sub.6) alkyl; Rb is selected from the group consisting of: H, (C.sub.1-C.sub.6) alkyl, and functional groups able to bind a vector and/or a biomolecule; and Y is a monovalent anion.

2. The method according to claim 1, wherein in the diaryliodonium compound of formula (II): ##STR00051## Ar.sub.1 and Ar.sub.2, independently of each other, are chosen from: (C.sub.6-C.sub.10)aryl and heteroaryl groups, said aryl and heteroaryl groups being substituted with one or several substituents selected from: (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkynyl, optionally substituted heteroaryl, halogen, NO.sub.2, CN, N.sub.3, CF.sub.3, ORa, COORb, C(O)Ra, NCO, NCS, N(Ra)COORb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)Rb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)(C.sub.1-C.sub.6)alkylene-Rb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)(C.sub.1-C.sub.6)alkylene-C(O)ORb and maleimidyl, said (C.sub.1-C.sub.6)alkyl group being optionally substituted with one or several substituents selected from N.sub.3, OH, OCH.sub.3, CF.sub.3, OCH.sub.2O(C.sub.1-C.sub.6)alkyl, O(C.sub.1-C.sub.6)alkenyl and O(C.sub.1-C.sub.6) alkylene-(C.sub.6-C.sub.10)aryl; Ra being H or (C.sub.1-C.sub.6)alkyl; Rb being selected from the group consisting of: H, (C.sub.1-C.sub.6)alkyl, succinimidyl, N-hydroxysuccinimidyl, sulfosuccinimidyl, maleimidyl, biotinyl, cyclooctynyl, norbornenyl, cyclopropenyl, bicyclononynyl, and trans-cyclooctenyl; and Y is a monovalent anion.

3. The method according to claim 1, wherein the diaryliodonium compound is of formula (II-1): ##STR00052## wherein: R.sub.1 is selected from the group consisting of: (C.sub.1-C.sub.6)alkyl, (C.sub.2-C.sub.6)alkynyl, optionally substituted heteroaryl, halogen, NO.sub.2, CN, N.sub.3, CF.sub.3, ORa, COORb, C(O)Ra, NCO, NCS, N(Ra)COORb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)Rb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)(C.sub.1-C.sub.6)alkylene-Rb, (C.sub.1-C.sub.6)alkylene-N(Ra)C(O)(C.sub.1-C.sub.6)alkylene-C(O)ORb, and maleimidyl, said (C.sub.1-C.sub.6)alkyl group being optionally substituted with one or several substituents selected from N.sub.3, OH, OCH.sub.3, CF.sub.3 and OCH.sub.2CHCH.sub.2; Ra and Rb being defined as in claim 1.

4. The method according to claim 1, wherein the astatoarene is of formula (I):
ArX(I) wherein: X is At; and Ar is Ar.sub.1 or Ar.sub.2.

5. The method of claim 1, wherein the astatide salt is of formula (III):
A.sup.+X.sup.(III) wherein: X is as defined in claim 4; and A is a monovalent cation selected among Na, K, Cs, tetraalkylammonium and tetraalkylphosphonium.

6. The method of claim 4, wherein X is radioactive.

7. The method according to claim 6, wherein X is .sup.211At.

8. The method of claim 1, wherein the reaction is carried out in a solvent selected from the group consisting of: acetonitrile, an alcohol, dimethylformamide, water, and mixtures thereof.

9. The method of claim 1, further comprising a purification step wherein the astatoarene is extracted by a solvent in which: an astatide salt and the diaryliodonium salt of formula (II) are insoluble, and said astatoarene is soluble.

10. The method of claim 1, further comprising a step of reducing astatine prior to the step of reacting.

11. A method of synthesizing an astatolabeled biomolecule and/or vector comprising the steps of: (i) synthesizing an astatoarene according to the method of claim 1; (ii) reacting said astatoarene with a biomolecule and/or a vector carrying a functional group reactive with said astatoarene.

12. The method according to claim 11, wherein the astatoarene is of formula (I):
ArX(I) where X is radioactive.

13. The method of claim 1, wherein Y is chosen from: CF.sub.3COO, TsO, MsO, NsO, TfO, NO.sub.3, Br, Cl, SO.sub.4 and BF.sub.4.

14. The method of claim 8, wherein the alcohol is methanol.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the percentage of the radiochemical yield (RCY) of the iodination reaction depending on the solvent and temperature used.

(2) FIG. 2 shows the percentage of the radiochemical yield (RCY) of the astatination reaction depending on the solvent and temperature used.

(3) Some examples are given below, without limitation of the present invention.

EXAMPLES

(4) RCY means radiochemical yield.

(5) ACN means acetonitrile.

Example 1

Synthesis of Diaryliodonium Salts of Formula (II)

(6) All reagents and solvents were obtained commercially and used without further purification unless otherwise noted. .sup.1H NMR and .sup.13C NMR spectra were recorded on a Bruker Advance 300 MHz instrument, and chemical shifts are reported in ppm on the 6 scale relative to TMS. Electrospray ionization-mass spectra (ESI-MS) were acquired using an Agilent LC/MSD system equiped with a multimode ion. Elemental analyses were performed by Galbraith Lab. Inc. (Knoxville, Tenn.) using combustion analysis methods for C, H, and N.

1. General Method for the Preparation of the aryl-4-methoxyphenyliodonium tosylates, Compounds of Formula (II)

(7) 3-chloroperbenzoic acid dried in vacuo for 1 h prior to use (1.77 mmol) was dissolved in CHCl.sub.3 (15 mL) and the iodoaryl was added (1.5 mmol). The solution was stirred at rt for 15 min. and turned slightly yellow and cloudy. 4-toluenesulfonic acid hydrate (1.77 mmol) and anisole (8.05 mmol) were then added and the solution was heated for 2 h30 at 40 C., turning bright yellow. The solvent was evaporated in vacuo and the oily residue was triturated in Et.sub.2O until it turned into a solid. The solid was redissolved in the minimum amount of MeOH and Et.sub.2O was added until the solution became cloudy. It was placed in the fridge at 4 C. until the iodonium tosylate precipitates or crystallizes.

1.1. Phenyl(4-methoxyphenyl)iodonium tosylate

(8) White solid (47%). .sup.1H NMR (CDCl.sub.3, 300 MHz, ppm): 2.02 (s, 1H, broad), 2.30 (s, 3H), 3.78 (s, 3H), 6.83 (d, 2H, J=9.0 Hz), 7.02 (d, 2H, J=7.8 Hz), 7.29-7.34 (m, 2H), 7.44-7.52 (m, 3H), 7.85-7.92 (m, 4H). .sup.13C NMR (CDCl.sub.3, 75 MHz, ppm): 21.5, 55.8, 104.1, 116.0, 117.7, 126.2, 128.7, 131.6, 131.8, 134.7, 137.6, 139.5. ESI-MS: m/z=311.0 [M-OTs].sup.+, 793.0 [2M-OTs].sup.+. Mp: 154 C. C.sub.20H.sub.19IO.sub.4S, calculated: C, 49.80; H, 3.97. Found: C, 49.97; H, 3.88.

1.2. 4-tolyl(4-methoxyphenyl)iodonium tosylate

(9) Colorless crystals (77%). .sup.1H NMR (CDCl.sub.3, 300 MHz, ppm): 2.04 (s, 1H, broad), 2.31 (s, 3H), 2.33 (s, 3H), 3.78 (s, 3H), 6.81 (d, 2H, J=9.3 Hz), 7.02 (d, 2H, J=8.1 Hz), 7.11 (d, 2H, J=8.4 Hz), 7.52 (d, 2H, J=8.1 Hz), 7.79 (d, 2H, J=8.4 Hz), 7.85 (d, 2H, J=9.3 Hz). .sup.13C NMR (CDCl.sub.3, 75 MHz, ppm): 21.4, 21.5, 55.8, 104.1, 112.2, 117.6, 126.2, 128.6, 132.6, 134.7, 137.3, 139.4, 142.5, 143.0, 162.4. ESI-MS: m/z=325.0 [M-OTs].sup.+, 821.0 [2M-OTs].sup.+. Mp: 169 C. C.sub.21H.sub.21IO.sub.4S, calculated: C, 50.82; H, 4.26. Found: C, 51.07; H, 4.03.

1.3. 3-tolyl(4-methoxyphenyl)iodonium tosylate

(10) Colorless crystals (69%). .sup.1H NMR (CDCl.sub.3, 300 MHz, ppm): 1.93 (5, 1H, broad), 2.29 (s, 3H), 2.31 (s, 3H), 3.79 (s, 3H), 6.84 (d, 2H, J=9.3 Hz), 7.04 (d, 2H, J=8.1 Hz), 7.18-7.29 (m, 2H), 7.54 (d, 2H, J=8.1 Hz), 7.68 (d, 1H, J=8.1 Hz), 7.74 (5, 1H), 7.87 (d, 2H, J=9.3 Hz). .sup.13C NMR (CDCl.sub.3, 75 MHz, ppm): 21.4, 21.5, 55.8, 103.8, 115.7, 117.7, 126.2, 128.6, 131.5, 131.7, 132.6, 135.1, 137.5, 139.4, 142.4, 143.1, 162.5. ESI-MS: m/z=325.0 [M-OTs].sup.+, 821.0 [2M-OTs].sup.+. Mp: 123 C. C.sub.21H.sub.21IO.sub.4S, calculated: C, 50.82; H, 4.26. Found: C, 50.89; H, 4.24.

1.4. 2-tolyl(4-methoxyphenyl)iodonium tosylate

(11) Colorless crystals (82%). .sup.1H NMR (CDCl.sub.3, 300 MHz, ppm): 2.17 (5, 1H, broad), 2.29 (s, 3H), 2.55 (s, 3H), 3.76 (s, 3H), 6.79 (d, 2H, J=9.3 Hz), 6.99 (d, 2H, J=8.1 Hz), 7.10-7.15 (m, 1H), 7.32 (d, 1H, J=6.6 Hz), 7.39-7.46 (m, 3H), 7.79 (d, 2H, J=9 Hz), 8.1 (m, 1H). .sup.13C NMR (CDCl.sub.3, 75 MHz, ppm): 21.5, 25.8, 55.7, 103.5, 117.5, 120.9, 126.1, 128.6, 129.2, 131.6, 132.7, 136.7, 137.5, 129.3, 141.3, 143.0, 162.2. ESI-MS: m/z=325.0 [M-OTs].sup.+, 821.0 [2M-OTs].sup.+. Mp: 155 C. C.sub.21H.sub.21IO.sub.4S, calculated: C, 50.82; H, 4.26. Found: C, 50.90; H, 4.19.

1.5. 4-chlorophenyl(4-methoxyphenyl)iodonium tosylate

(12) White solid (80%). .sup.1H NMR (DMSO-d.sub.6, 300 MHz, ppm): 2.29 (s, 3H), 3.80 (s, 3H), 7.06-7.12 (m, 4H), 7.47 (d, 2H, J=7.8 Hz), 7.59 (d, 2H, J=8.4 Hz), 8.16-8.22 (m, 4H). .sup.13C NMR (DMSO-d.sub.6, 75 MHz, ppm): 20.8, 55.7, 105.7, 114.9, 117.5, 125.5, 128.0, 131.6, 136.6, 137.1, 137.2, 137.6, 145.7, 162.0. ESI-MS: m/z=344.9/346.9 [M-OTs].sup.+, 860.9/862.9 [2M-OTs].sup.+. Mp: 186 C. C.sub.20H.sub.18ClIO.sub.4S, calculated: C, 46.48; H, 3.51. Found: C, 46.54; H, 3.39.

1.6. 4-(ethoxycarbonyl)phenyl(4-methoxyphenyl)iodonium tosylate

(13) White solid (59%). .sup.1H NMR (CDCl.sub.3, 300 MHz, ppm): 1.36 (t, 3H, J=7.0 Hz), 2.25 (s, 1H, broad), 2.29 (s, 3H), 3.77 (s, 3H), 4.35 (q, 2H, J=7.0 Hz), 6.79 (d, 2H, J=9.0 Hz), 6.97 (d, 2H, J=7.8 Hz), 7.49 (d, 2H, J=8.1 Hz), 7.84-7.92 (m, 4H), 7.99 (d, 2H, J=8.1 Hz). .sup.13C NMR (CDCl.sub.3, 75 MHz, ppm): 14.4, 21.4, 55.7, 61.8, 104.5, 117.6, 121.0, 126.1, 128.6, 132.1, 133.1, 134.8, 137.9, 139.5, 142.6, 162.5, 165.3. ESI-MS: m/z=383.0 [M-OTs].sup.+, 937.0 [2M-OTs].sup.+. Mp: 137 C. C.sub.23H.sub.23IO.sub.6S, calculated: 0, 49.83; H, 4.18. Found: C, 49.78; H, 4.14.

1.7. 4-nitrophenyl(4-methoxyphenyl)iodonium tosylate

(14) White solid (36%). .sup.1H NMR (DMSO-d.sub.6, 300 MHz, ppm): 2.29 (s, 3H), 3.80 (s, 3H), 7.08-7.11 (m, 4H), 7.47 (d, 2H, J=8.1 Hz), 8.22-8.30 (m, 4H), 8.42 (d, 2H, J=8.7 Hz). .sup.13C NMR (DMSO-d.sub.6, 75 MHz, ppm): 20.8, 55.8, 117.6, 117.6, 123.2, 125.5, 126.1, 128.0, 136.0, 137.6, 145.8, 149.2, 162.2. ESI-MS: m/z=355.9 [M-OTs].sup.+, 883.0 [2M-OTs].sup.+. Mp: 192 C. C.sub.20H.sub.18INO.sub.6S+H.sub.2O, calculated: C, 44.79; H, 3.57; N, 2.61. Found: C, 44.70; H, 3.18; N, 2.38.

1.8. 3-nitrophenyl(4-methoxyphenyl)iodonium tosylate

(15) White solid (35%). .sup.1H NMR (DMSO-d.sub.6, 300 MHz, ppm): 2.28 (s, 3H), 3.80 (s, 3H), 7.10 (m, 4H), 7.46 (d, 2H, J=7.8 Hz), 7.79 (m, 1H), 8.26 (d, 2H, J=8.7 Hz), 8.43 (d, 1H, J=7.8 Hz), 8.59 (d, 1H, J=7.8 Hz), 9.12 (s, 1H). .sup.13C NMR (DMSO-d.sub.6, 75 MHz, ppm): 20.8, 55.7, 105.9, 116.9, 117.6, 125.5, 126.5, 128.0, 129.5, 132.6, 137.5, 137.6, 140.8, 145.7, 148.2, 162.2. ESI-MS: m/z=355.9 [M-OTs].sup.+, 883.0 [2M-OTs].sup.+. Mp: 174 C. C.sub.20H.sub.18INO.sub.6S, calculated: C, 45.55; H, 3.44; N, 2.66. Found: C, 45.53; H, 3.20; N, 2.37.

1.9. 4-cyanophenyl(4-methoxyphenyl)iodonium tosylate

(16) White solid (45%). .sup.1H NMR (DMSO-d.sub.6, 300 MHz, ppm): 2.29 (s, 3H), 3.80 (s, 3H), 7.10 (m, 4H), 7.47 (d, 2H, J=7.8 Hz), 7.98 (d, 2H, J=8.1 Hz), 8.21 (d, 2H, J=8.7 Hz), 8.36 (d, 2H, J=8.1 Hz). .sup.13C NMR (DMSO-d.sub.6, 75 MHz, ppm): 20.7, 55.7, 105.5, 114.4, 117.5, 117.6, 121.1, 121.8, 125.5, 128.0, 134.8, 135.4, 137.5, 145.7, 162.3. ESI-MS: m/z=336.0 [M-OTs].sup.+, 842.9 [2M-OTs].sup.+. Mp: 208 C. C.sub.21H.sub.18INO.sub.4S+H.sub.2O, calculated: C, 48.01; H, 3.84; N, 2.67. Found: C, 47.90; H, 3.15; N, 2.34.

1.10. 4-azidophenyl(4-methoxyphenyl)iodonium tosylate

(17) White solid (60%) .sup.1H NMR (400 MHz, CD.sub.3CN): 7.99-7.94 (m, 4H), 7.42 (d, 2H, 8 Hz), 7.09 (d, 2H, 8 Hz), 6.99 (d, 2H, 9.2 Hz), 6.95 (d, 2H, 9.2 Hz), 3.79 (s, 3H), 2.32 (s, 3H) .sup.13C NMR (100 MHz, CDCl.sub.3): 163.8, 145.6, 145.5, 140.0, 138.3, 137.7, 129.4, 126.6, 123.20, 118.56, 110.3, 104.9, 56.6, 21.3 ESI-MS: m/z=352.3 [M-OTs].sup.+, 875.5 [2M-OTs].sup.+.

1.11. 4-azidomethylphenyl(4-methoxyphenyl)iodonium tosylate

(18) White solid (74%) .sup.1H NMR (400 MHz, CD.sub.3CN): 8.01-7.95 (m, 4H), 7.55 (d, 1H, 7.6 Hz), 7.46-7.43 (m, 3H), 7.09 (d, 2H, 8 Hz), 6.96 (d, 2H, 9.2 Hz), 4.40 (s, 2H), 3.80 (s, 3H), 2.31 (s, 3H) .sup.13C NMR (100 MHz, CDCl.sub.3): 163.6, 145.3, 141.0, 140.1, 138.4, 135.2, 135.1, 132.8, 132.5, 129.3, 126.5, 118.4, 116.7, 104.5, 56.5, 53.9, 21.1. ESI-MS: m/z=366.3 [M-OTs].sup.+, 903.6 [2M-OTs].sup.+.

1.12. 4-ethynylphenyl(4-methoxyphenyl)iodonium tosylate

(19) White solid (64%). .sup.1H NMR (400 MHz, CD.sub.3CN): 7.97-7.95 (m, 4H), 7.52-7.48 (m, 4H), 7.11 (d, 2H, 7.6 Hz), 7.05 (d, 2H, 8.8 Hz), 3.82 (s, 3H), 3.61 (s, 1H), 2.32 (s, 3H) .sup.13C NMR (100 MHz, CD.sub.3CN): 160.6, 142.0, 139.4, 136.2, 134.8, 132.3, 130.0, 128.2, 122.7, 120.3, 114.3, 111.9, 81.5, 80.7, 56.3, 19.9. ESI-MS: m/z=335.3 [M-OTs].sup.+, 841.5 [2M-OTs].sup.+.

1.13 3-N-hydroxysuccinimidylphenyl ester(4-methoxyphenyl)iodonium tosylate)

(20) Beige solid (36%). .sup.1H NMR (400 MHz, CD.sub.3CN): 2.31 (s, 3H), 2.86 (s, 4H), 3.81 (s, 3H), 6.98 (m, 2H), 7.09 (d, 2H, J=7.6 Hz), 7.42 (m, 2H), 7.61 (t, 1H, J=8.0 Hz), 8.00 (m, 2H), 8.25 (m, 1H), 8.31 (m, 1H), 8.71 (m, 1H). .sup.13C NMR (100 MHz, CD.sub.3CN): 21.2, 26.4, 56.5, 104.5, 116.7, 118.6, 126.5, 128.7, 129.3, 133.3, 134.2, 137.0, 138.7, 140.1, 141.7, 145.2, 161.3, 163.9, 170.8. ESI-MS: m/z=452.2 [M-OTs].sup.+. 5-10% of hydrolyzed ester were also detected.

1.14 N-hydroxysuccinimidylphenyl ester(4-methylethoxyphenyl)iodonium tosylate)

(21) Was as white crystals (39%). .sup.1H NMR (CD3CN, 300 MHz, ppm): 1.29 (d, 6H, J=6.0 Hz), 2.31 (s, 3H), 2.86 (s, 4H), 4.64 (m, 1H), 6.95 (m, 2H), 7.9 (d, 2H, J=7.6 Hz), 7.44 (m, 2H), 7.62, t, 1H, J=8.0 Hz), 7.97 (m, 2H), 8.27, m, 2H), 8.71 (s, 1H). .sup.13C NMR (100 MHz, CD.sub.3CN): 15.6, 21.2, 21.9, 26.5, 71.7, 103.8, 116.7, 120.0, 126.5, 128.8, 129.4, 133.4, 134.3, 137.0, 138.9, 140.1, 141.7, 145.4, 161.3, 162.5, 170.9. ESI-MS: m/z=480.2 [M-OTs].sup.+. 10% of hydrolyzed ester were also detected.

2. General Method for the Preparation of Iodonium Triflates

(22) 3-chloroperbenzoic acid dried in vacuo for 1 h prior to use (504 mol) was dissolved in CH.sub.2Cl.sub.2 (5 mL) and the iodoarene was added (458 mol). After 15 min of stirring at room temperature, the desired arene (anisole, 1-methylethoxybenzene or thiophene, 504 mol) was added, the solution cooled to 20 C. and triflic acid (916 mol) was added. The resulting dark solution was stirred at 20 C. for 15 min. After returning to room temperature, the solvent was romoved in vacuo and the residue was by flash chromatography using the appropriate gradient of CH.sub.2Cl.sub.2 and iPrOH. The resulting purified iodonium triflate was then crystallyzed from CH.sub.3CN/Et.sub.2O. Compounds described in 2.1, 2.2, 2.3, 2.4 and 2.5 were obtained using this procedure

2.1 3-N-hydroxysuccinimidylphenyl ester(4-methoxyphenyl)iodonium triflate)

(23) Was obtained from N-hydroxysuccinimidylphenyl ester and anisole as white crystals (28%). .sup.1H NMR (CD3CN, 300 MHz, ppm): 2.86 (s, 4H), 3.85 (s, 3H), 7.08 (d, 2H, J=6.9 Hz), 7.73 (t, 1H, J=6.0 Hz), 8.05 (d, 2H, J=6.9 Hz), 3.22-8.36 (m, 2H), 8.75 (s, 1H). .sup.13C NMR (100 MHz, CD.sub.3CN): 26.5, 56.8, 102.2, 114.8, 119.3, 129.4, 134.0, 135.0, 137.0, 139.0, 141.7, 161.2, 164.6, 170.8. ESI-MS: m/z=452.2 [M-OTf].sup.+, 1053.0 [2M-OTf].sup.+.

2.2 3-N-hydroxysuccinimidylphenyl ester(4-methylethoxyphenyl)iodonium triflate)

(24) Was obtained from N-hydroxysuccinimidylphenyl ester and 1-methylethoxybenzene as white crystals (36%). .sup.1H NMR (CD3CN, 300 MHz, ppm): 1.96 (m, 6H), 2.88 (s, 4H), 4.70 (m, 1H), 7.05 (m, 2H), 7.74 (t, 1H, J=8.0 Hz), 8.05 (m, 2H), 8.36 (m, 2H), 8.75 (s, 1H). ESI-MS: m/z=480.3 [M-OTf].sup.+,

2.3 3-N-hydroxysuccinimidylphenyl ester(2-thienyl)iodonium triflate

(25) Was obtained from N-hydroxysuccinimidylphenyl ester and 1-methylethoxybenzene as white crystals (17%). .sup.1H NMR (CD3CN, 300 MHz, ppm): 2.88 (s, 4H), 7.24 (m, 1H), 7.76 (t, 1H, J=8.0 Hz), 7.94 (m, 1H), 8.05 (m, 1H), 8.38 (m, 2H), 8.82, s, 1H). ESI-MS: m/z=428.5 [M-OTf].sup.+,

2.44-methyl-2-[2,2,2-trifluoro-1-allyloxy-1-(trifluoromethypethyl]phenyl-(4-methoxyphenypiodonium triflate)

(26) Was obtained as beige crystals (56%).sup.1H NMR (400 MHz, CD.sub.3CN): 2.44 (s, 3H), 3.95 (s, 3H), 4.94 (d, 2H, J=6.0 Hz), 5.57 (d, 1H, J=10, 4 Hz), 5.72 (d, 1H, J=17.2 Hz), 6.17-6.27 (m, 1H), 7.09 (d, 1H, J=8.6 Hz), 7.21 (d, 1H, J=9.0 Hz), 7.37 (m, 1H), 7.73 (s, 1H), 8.03 (d, 1H, J=9.0 Hz). ESI-MS: m/z=517.3 [M-OTf].sup.+.

(27) 2.54-methyl-2-[2,2,2-trifluoro-1-methoxy-1-(trifluoromethypethyl]phenyl-(4-methoxyphenyl)iodonium triflate) Was obtained as beige crystals (53%). .sup.1H NMR (400 MHz, CD.sub.3CN): 2.44 (s, 3H), 3.96 (s, 3H), 4.08 (s, 3H), 7.07 (d, 1H, J=8.6 Hz), 7.23 (d, 2H, J=9.2 Hz), 7.39 (d, 1H, J=8.6 Hz), 7.72 (s, 1H), 8.07 (d, 2H, J=9.2 Hz). ESI-MS: m/z=491.2 [M-OTf].sup.+.

2.6 4-maleimidophenyl-(2-thienyl)iodonium triflate

(28) Was obtained as colorless crystals (29%). %). .sup.1H NMR (400 MHz, CD.sub.3CN): 6.98 (s, 2H), 7.23 (m, 1H), 7.58 (d, 2H, J=7.2 Hz), 7.92 (d, 1H, J=5.4 Hz), 8.02 (d, 1H, J=5.4 Hz), 8.16 (d, 2H, J=7.2 Hz). ESI-MS: m/z=491.2 [M-OTf].sup.+.

Example 2

Radiochemistry

(29) [.sup.125I] was obtained commercially from Perkin-Elmer (Shelton, Conn.) in 10.sup.5 M NaOH solution with a volumic acitivity of 50 Ci/L (1.85 MBq/L) and was diluted as desired in deionized water before use. .sup.211At was produced using the .sup.209Bi(,2n).sup.211At reaction by bombarding a disposable internal bismuth target with -particles from the Cyclotron Corporation CS-30 cyclotron in the National Institutes of Health Positron Emission Tomography Department. .sup.211At was recovered from the irradiated target in acetonitrile using the dry-distillation procedure described in Lindegren, S.; Back, T.; Jensen, H. J. Appl Rad Isot 2001, 55, 157

(30) Before use, the .sup.211At solution was diluted twice in a 10 mg/mL aqueous solution of Na.sub.2SO.sub.3, resulting in a 1:1 ACN/water solution of NaAt.

(31) Alternatively, .sup.211At was produced at the Arronax facility (St Herblain, France) using an identical nuclear reaction and dry distilled using the same procedure. In this case, .sup.211At was recovered in chloroform (CHCl.sub.3), the solution evaporated to dryness under a stream of nitrogen. The dry astatine was then redissolved in an appropriate volume of 1 mg/mL or 10 mg/mL aqueous sodium sulfite before use in astatination reactions.

1.1 Reaction of Iodonium Salts with .SUP.125.I

(32) To 950 nmol of iodonium salt in 190 L of the selected solvent equilibrated at the appropriate temperature of reaction was added 10 L (typically 1.5 MBq) of [.sup.125I]-NaI prepared from commercial [.sup.125I]-NaI in 10.sup.5 NaOH and diluted in the appropriate amount of ultrapure water. At desired times, aliquots were withdrawn and deposited on a silica gel TLC plate and eluted with the appropriate solvent, and/or diluted in a 1/1 mixture of water/ACN and analyzed by reverse phase HPLC using the appropriate elution system. Retention indexes and elution systems used for all compounds of this study are given in ESI. Aromatic .sup.125I species were identified by comparison of the retention index of the cold analogues.

1.2 Reaction of Iodonium Salts with .SUP.211.At

(33) To 950 nmol of iodonium salt in 180 L of the selected solvent and equilibrated at the appropriate temperature of reaction, was added 20 L (typically 5 MBq) of [.sup.211At]-NaAt prepared as described above. At desired times, aliquots were withdrawn and deposited on a silica gel TLC plate and eluted with the appropriate solvent, and/or diluted in a 1/1 mixture of 0.1 N HCl/ACN. The same elution systems as in .sup.125I procedures were used. The retention indexes of astatinated compounds were nearly identical to their iodinated analogues.

(34) TABLE-US-00001 TABLE 1 RCY and selectivity for target product of the radioiodination at 90 C. and astatination at 80 C. of asymmetric iodonium tosylates in ACN-5% H.sub.2O (30 min, n = 3). 0 .sup.125I .sup.211At RPhI: G.sub.TS RPhAt: G.sub.TS RCY.sub.total.sup.a MeOPhI (kcal/mol) RCY.sub.total.sup.a MeOPhAt (kcal/mol) R (%) ratio exp. (%) ratio exp. H 61 +/ 2 4.8:1 1.13 97 +/ 1 4.2:1 1.04 4-Me 43 +/ 6 1.5:1 0.29 97 +/ 1 2:1 0.50 3-Me 61 +/ 1 4.4:1 1.07 99 +/ 1 3.7:1 0.94 2-Me 98 +/ 1 27:1 2.38 98 +/ 1 8.1:1 1.51 4-Cl 68 +/ 2 8:1 1.50 98 +/ 1 5.3:1 1.20 4-CO.sub.2Et 96 +/ 1 35:1 2.56 98 +/ 1 8.2:1 1.52 4-CN 97 +/ 1 >50:1 >2.82 99 +/ 1 16:1 2.00 3-NO.sub.2 82 +/ 19:1 ND.sup.b 99 +/ 1 24:1 2.29 4.sup.b 4-NO.sub.2 92.sup. >50:1 >2.82 99 +/ 1 29:1 2.43 4-CH.sub.2N.sub.3 87.sup.c 14:1 75.sup. 6.5:1 4-N.sub.3 59.sup.c 11:1 61.sup.d 2.5:1 4-CCH 59.sup.c 11:1 71.sup.c 6:1 3-CONHS 93.sup.d 11:1 .sup.aDecay corrected. .sup.bPresence of 10-15% unidentified side products. .sup.cReaction at 120 C., .sup.dreaction at 60 C.

(35) These results show that good yields are obtained for the iodination reaction and that high yields (superior to 70%) are obtained with the astatination reaction, independently of the substituents present on the phenyl ring

Example 3

Radiolabelling of a Biomolecule

(36) AIodolabelled biomolecule

1Preparation of [.SUP.125.I]-SIB (N-succinimidvl 3-iodobenzoate) of formula (I)

(37) ##STR00031##

(38) To 95 L of 5 mM iodonium salt in ACN placed in a 1 mL glass vial was added 5 L (50 to 500 Ci) [.sup.125I] NaI prepared as described above. The solution was heated for 30 min at 90 C. After cooling to room temperature, an aliquot was withdrawn and analyzed by reverse phase HPLC showing the formation of [.sup.125I]-SIB with a radiochemical yield (RCY) of 86%. The sides products were [.sup.125I]-2-iodothiophene (2%), [.sup.125I]-3-iodobenzoic acid (1.5%) and 10% of unreacted .sup.125I.sup. and degradation products.

(39) Purification of [.sup.125I]-SIB was performed as follow:

(40) After reduction of the labeling mixture to dryness under a stream of dry nitrogen, 100 L of Et.sub.2O were added. The vial was vortexed for 30 s and the Et.sub.2O was transferred to a second 1 mL vial. The Et.sub.2O extraction procedure was repeated twice. An aliquote of the combined Et.sub.2O layers was analyzed by HPLC, revealing the presence of 98% pure [.sup.125I]-SIB, the remaining 2% corresponding to [.sup.125I]-3-iodobenzoic acid. After reduction to dryness under a stream of nitrogen, the [.sup.125I]-SIB can be reconditionned into the appropriate medium for conjugation to the chosen biomolecule/vector.

(41) In this extraction procedure, Et.sub.2O can be replaced by toluene.

(42) [.sup.125I]-SIB was also produced from the following iodonium precursors using identical reaction conditions.

(43) TABLE-US-00002 % [.sup.125I]-3- Ar % [.sup.125I]-SIB iodobenzoic acid % .sup.125I-Ar MeOPh (100 C.) 36 3 2 iPrOPh (100 C.) 50 3 1 2-thienyl (100 C.) 87 1.5 1 80 C. 67 2 <1 60 C. 7 0 0

2-Conjugation of [.SUP.125.I]-SIB to IgG 9E7.4

(44) To [.sup.125I]-SIB obtained as described above, placed in a 1 mL V-vial and reduced to dryness under a stream of N.sub.2, was added 20 L of DMSO. The solution was vortexed for 30 s and 100 L of a 5.65 mg/mL of 9E7.4 IgG (anti CD138) in 0.3M borate buffer at pH 8.6 was added. After 30 min of agitation at 20 C., a chromatographic control using an ITLC-SG strip and 10% TCA as eluant indicated 75% conjugation yield. The solution was purified by gel filtration (PD10 column) using PBS as eluent, affording pure radiolabeled 9E7.4 IgG (radiochemical purity >99% as verified by ITLC-SG).

(45) The same coupling reaction has been carried out with [.sup.211At]-SAB, with a 75-88% conjugation yield (n=3) and preservation of the antibody immunoreactivity (85%).

3Other Radioiodinated Compounds of Formula (I) Obtained By the Same Procedure

(46) ##STR00034##

(47) The reaction was carried out at 120 C. for 30 mn resulting in the formation of [.sup.125I]-1-azidomethyl-4-iodobenzene (81% RCY) and [.sup.125I]-iodoanisole (6%).

(48) ##STR00035##

(49) The reaction was carried out at 120 C. for 30 mn resulting in the formation of [.sup.125l]-1-azido-4-iodobenzene (54% RCY) and [.sup.125I]-iodoanisole (5%).

(50) ##STR00036##

(51) The reaction was carried out at 120 C. for 30 mn resulting in the formation of [.sup.125I]-1-ethynyl-4-iodobenzene (54% RCY) and [.sup.125I]-iodoanisole (5%).

4-Click Conjugation of [.SUP.125.I]-1-azidomethyl-4-iodobenzene (81% RCY) with a Model tripeptide

(52) ##STR00037##

(53) After preparation as described above, the [.sup.125I]-1-azidomethyl-4-iodobenzene labelling solution was reduced to dryness upon which [.sup.125I]-iodoanisole side product was eliminated by evaporation together with the solvent, resulting in an analytically pure [.sup.125I]-1-azidomethyl-4-iodobenzene sample (HPLC) in the Et.sub.2O extract. After reduction to dryness, 1004 of the click tripeptide (1.5 mg/mL in H.sub.2O/ACN (8:2)) was added and the vial was stirred at room temperature for 3 hours. HPLC analysis showed a conjugation yield>99%.

(54) BAstatoarene

1Preparation of [.SUP.211.At]-SAB(N-succinimidyl 3-astatobenzoate)

(55) ##STR00038##

(56) Astatine-211 was provided by the Arronax facility (St Herblain, France) in chloroform solution. Before use, it was reduced in At(I) form by evaporation of the chloroform to dryness under a stream of nitrogen and redissolution in a 1 mg/mL sodium sulfite solution. Then, in a 1 mL vial was added 5 L of Na.sup.211At to 95 L of the iodonium in ACN at a 5 mM concentration. After heating at 25 C. to 100 C. for 30 min, an aliquot was analyzed by HPLC.

(57) TABLE-US-00003 % [.sup.211At]-3- Ar % [.sup.211At]-SAB astatobenzoic acid % .sup.211AtAr MeOPh 92 (100 C.) <1 6 93 (60 C.) 0 5 91 (40 C.) 0 6 49% (25 C.) 0 4 iPrOPh 85 (100 C.) <1 6 2-thienyl 79 (100 C.) 0 12

(58) The same extraction procedure employed for radioiodination using Et.sub.2O when R=MeOPh provided [.sup.211At]-SAB with 95% purity, with 5% 4-astatoanisole.

(59) In particular, the above table shows the unexpected high reactivity of the .sup.211At, even at low temperature (see for example 91% yield at 40 C. for MeOPh). In comparison, good yield are obtained with .sup.125I above 80 C.

2Other Astatinated Compounds Obtained by the Same Procedure

(60) ##STR00039##

(61) The reaction was carried out at 80 C. for 30 mn resulting in the formation of [.sup.211At]-1-azidomethyl-4-astatobenzene (65% RCY) and [.sup.211At]-astatoanisole (10%).

(62) ##STR00040##

(63) The reaction was carried out at 60 C. for 30 mn resulting in the formation of [.sup.211At]-1-azido-4-astatobenzene (44% RCY) and [.sup.211At]-astatoanisole (17%).

(64) ##STR00041##

(65) The reaction was carried out at 120 C. for 30 mn resulting in the formation of [.sup.211At]-1-ethynyl-4-astatobenzene (66% RCY) and [.sup.211At]-astatoanisole (11%).

Example 4

Comparison Between Iodination and Astatination

(66) Results of the influence of temperature and solvent study are displayed in FIGS. 1 and 2 and show a clearly distinct reactivity between iodide and astatide.

(67) In the case of iodination, the use of ACN leads to high RCYs above 100 C., with up to 93% at 120 C.

(68) In contrast, all solvent conditions gave RCYs superior to 80% at 100 C. or below for the astatination reaction. This shows a strong difference in terms of reactivity between the two halogens. The reactivity of astatine could not have been derived from the iodine reactivity.

Example 5

(69) Synthesis:

(70) ##STR00042##

(71) The starting 3-(p-iodophenyl)-6-methyl-1,2,4,5,tetrazine was prepared as previously reported (Angewandte, 2012, 5222-52252). The preparation of the aryliodonium salt was adapted from a previously reported procedure (Eur. J. Org. Chem. 2015, 5919-5924):

(72) To a solution of Selectfluor (177 mg, 470 mop in dry acetonitrile (5 mL) under argon was added TMSOAC (139 mg, 1.02 mmol) and the solution was stirred at room temperature until the solution becomes clear (15 min). It was then added dropwise to a solution of 3-(p-iodophenyl)-6-methyl-1,2,4,5,tetrazine (101 mg, 340 mol) dissolved in dry acetonitrile (7.5 mL). The mixture was then stirred at room temperature for 24 h under Argon. To the solution was then added 4-methoxyphenyltrifluoroborate (84 mg, 370 mol) and TMSOTFA (72 mg, 370 mol) and the solution was stirred at room temperature under argon for 4 days. Volatiles were removed by rotary evaporation and the crude product was purified by flash chromatography (SiO.sub.2 with CH.sub.2Cl.sub.2/methanol gradient) to afford a purple solid (44 mg, 28%).

(73) NMR .sup.1H (CD.sub.3CN, 400 MHz, ppm): 3.05 (s, 3H), 3.84 (s, 3H), 7.08 (d, 2H, J=9.2 Hz), 8.06 (d, 2H, J=9.2 Hz), 8.23 (d, 2H, J=8.8 Hz), 8.59 (d, 2H, J=8.8 Hz). NMR .sup.13C (CD.sub.3CN, 100 MHz, ppm): 21.1, 56.4, 118.9, 131.4, 136.1, 136.9, 138.5, 163.5, 164.1, 168.8. NMR .sup.19F (CD.sub.3CN): 152.2. ESI-MS: m/z=405.3, [M-BF.sub.4].sup.+.

(74) Radiolabeling:

(75) ##STR00043##

(76) Radioiodination: To 95 L aryliodonium salt (5 mM in ACN) was added 5 L of Na.sup.125I. The solution was heated at 100 C. for 15 min. An HPLC analysis indicated the formation of 96% of radioiodinated tetrazine and 2% of radioiodinated anisole. The crude solution was evaporated to dryness, dissolved in 100 L AcOEt and purified on a normal phase silica gel cartridge (Sepak) by elution with 300 L AcOEt, affording pure radioiodinated tetrazine (>99% radiochemical purity by HPLC).

(77) Astatination: To 85 L aryliodonium salt (3 mM in MeOH) was added 15 L of Na.sup.211At (in 1 mg/mL aqueous Na.sub.2SO.sub.3/MeOH 1:2) and the solution was heated at 40 C. for 30 min. An HPLC analysis indicated formation of 91% of astatinated tetrazine and 9% astatinated anisole. The crude solution was evaporated to dryness, dissolved in 100 L AcOEt and purified on a normal phase silica gel cartridge (Sepak) by elution with 300 L AcOEt, affording pure astatinated tetrazine (>99% radiochemical purity by HPLC).

(78) Conjugation to Clickable Peptide:

(79) Conjugation to BCN Peptide:

(80) ##STR00044##

(81) To 90 L of BCN-peptide (100 g/mL in 99:1 H.sub.2O/MeOH) was added the astatinated tetrazine (10 L in MeOH) and the reaction was monitored by reverse phase HPLC. Conjugation yield was 85% after 5 min and >99% after 15 min at room temperature.

(82) Conjugation to TCO-Peptide:

(83) ##STR00045##

(84) To 90 L of TCO-peptide (100 g/mL in 99:1 H.sub.2O/MeOH) was added the astatinated tetrazine (10 L in MeOH) and the reaction was monitored by reverse phase HPLC. Conjugation yield was 97% after 1 min and >99% after 15 min at room temperature.

Example 6

(85) Synthesis:

(86) ##STR00046##

(87) To the starting aryliodide (500 mg, 1.05 mmol) in CH.sub.2Cl.sub.2 (6 mL) was added mCPBA (260 mg, 1.16 mmol). The solution was stirred at room temperature for 30 min. Anisole (228 mg, 2.11 mmol) was then added, the solution cooled at 20 C. and triflic acid was added (317 mg, 2.11 mmol). After 40 min of stirring at 20 C., the solution was concentrated by rotary evaporation, and the crude mixture purified by flash chromatography (SiO.sub.2, CHCl.sub.3/MeOH gradient) affording a brown oil. To this oil was added diethylether, and after stirring at room temperature, the pure iodonium salt precipitates (67 mg, 9%).

(88) NMR .sup.1H (CD.sub.3CN, 400 MHz, ppm): 2.44 (s, 3H), 3.92 (s, 3H), 5.45 (s, 2H), 7.07 (d, 1H, J=8.6 Hz), 7.15, (d, 2H, J=9.2 Hz), 7.36, (d, 1H, J=8.6 Hz), 7.60-7.52 (m, 5H), 7.77 (s, 1H), 7.90 (d, 2H, J=9.2 Hz). ESI-MS: m/z=581.1, [M-TfO].sup.+.

(89) Radiolabeling:

(90) ##STR00047##

(91) Step 1, Nucleophilic substitution: To a 1 mM solution of aryliodonium salt (285 L in ACN), is added Na.sup.211At (15 L in 1 mg/mL Na.sub.2SO.sub.3 solution). The solution is heated at 60 C. for 10 min. HPLC analysis indicated the formation of the expected astatinated species (>99%) with no traces of astatoanisole. The solution is evaporated under a stream of nitrogen, the residue dissolved in 100 L CH.sub.2Cl.sub.2 and deposited on a Sepak silica gel cartridge. Elution with 200 L CH.sub.2Cl.sub.2 afforded pure Astatinated compound (>99% radiochemical purity by HPLC).

(92) Step 2, deprotection: The purified astatinated compound in CH.sub.2Cl.sub.2 solution was evaporated to dryness and 100 L TFA were added and the mixture was agitated for about 15 min at room temperature. TFA was evaporated with a stream of nitrogen. To remove traces of remaining TFA, 100 L of CH.sub.3CN were added and evaporated with a nitrogen stream (repeated 3 times). HPLC analyses indicated that 93% of astatinated species corresponding to the expected deprotected product has formed.

(93) Step 3, hypervalent astatine formation: The dry deprotected astatinated compound was dissolved in 100 L CCl.sub.4. 37% hydrochloric acid (2 L) followed by NaOCl (2 L) were then added and the reaction heated at 60 C. for 15 min. An aliquot was then analyzed by HPLC which showed conversion of 90% of starting material into the hypervalent species. To further confirm the identity of the hypervalent species, the CCl.sub.4 solution was evaporated under N.sub.2 stream and dissolved in 75 L CH.sub.3CN. 20 L Na.sub.2SO.sub.3 solution (100 mg/mL) were added and the solution was heated for 15 min at 60 C. HPLC Analysis of an aliquot of this solution showed 75% of initial hypervalent species had revert back to the monovalent form.

Example 7

(94) Synthesis:

(95) ##STR00048##

(96) To the starting aryliodide (293 mg, 0.45 mmol) in CH.sub.2Cl.sub.2 (3 mL) was added mCPBA (111 mg, 0.49 mmol). The solution was stirred at room temperature for 30 min. Anisole (97 mg, 0.9 mmol) was then added, the solution cooled at 20 C. and triflic acid was added (135 mg, 0.9 mmol). After 15 min of stirring at 20 C., the solution was concentrated by rotary evaporation, and the crude mixture purified by flash chromatography (SiO.sub.2, CH.sub.2Cl.sub.2/MeOH gradient) affording a brown oil. Crystallization in ACN/Et.sub.2O provided the compound as colorless crystals (18 mg, 4%).

(97) NMR .sup.1H (CD.sub.3CN, 400 MHz, ppm): 2.68 (t, 2H), 2.90 (s, 2H), 3.69 (t, 2H), 3.90 (s, 3H) 4.59 (s, 3H), 5.44 (s, 2H), 6.73 (s, 2H), 7.13 (m, 3H), 7.36 (m, 1H), 7.51 (m, 2H), 7.60 (m, 2H), 7.75 (s, 1H), 7.90 (m, 2H). ESI-MS: m/z=760.9.

(98) Radiolabeling:

(99) ##STR00049##

(100) Step 1, Nucleophilic substitution: To a 1 mM solution of aryliodonium salt (285 L in ACN), is added Na.sup.211At (15 L in 1 mg/mL Na.sub.2SO.sub.3 solution). The solution is heated at 60 C. for 10 min. HPLC analysis indicated the formation of the expected astatinated species (>95%) with no traces of astatoanisole. The solution is evaporated under a stream of nitrogen, the residue dissolved in 100 L CH.sub.2Cl.sub.2 and deposited on a Sepak silica gel cartridge. Elution with 200 L CH.sub.2Cl.sub.2 afforded pure Astatinated compound (>99% radiochemical purity by HPLC).

(101) Step 2, deprotection: The purified astatinated compound in CH.sub.2Cl.sub.2 solution was evaporated to dryness and 100 L TFA were added and the mixture was agitated for about 15 min at 40 C. TFA was evaporated with a stream of nitrogen. To remove traces of remaining TFA, 100 L of CH.sub.3CN were added and evaporated with a nitrogen stream (repeated 3 times). HPLC analyses indicated that 92% of astatinated species corresponding to the expected deprotected product has formed.

(102) Step 3, hvpervalent astatine formation: The dry deprotected astatinated compound was dissolved in 100 L CCl.sub.4. 37% hydrochloric acid (2 L) followed by NaOCl (2 L) were then added and the reaction heated at 60 C. for 30 min. An aliquot was then analyzed by HPLC which showed conversion of 93% of starting material into the hypervalent species.