Phosphoric Acid → (1r,cis)-4-(6-Amino-9h-purin-9-yl)-2-cyclopentene-1-methanol o-diphosphate

Participants

Reaction Conditions

Reaction Steps

The title molecule was prepared by a modification of the method of Broom (Mishra, N. C. and Broom, A. D., J. Chem. Soc., Chem. Commun., 1991, 1276). (1R,cis)-4-(6-Amino-9H-purin-9-yl)-2-cyclopentene-1-methanol (Example 1, 231 mg, 1.0 mmol) was dissolved in trimethyl phosphate (5 mL). Phosphoryl chloride (0.27 mL, 3.0 mmol) was added to the stirred, cooled (0° C.) solution. After 3 hours, a solution of 86% phosphoric acid (1.14 g, 10 mmol) and tri-n-butylamine (2.4 mL, 10 mmol) in dimethyformamide (15 mL) was added to the cold (0° C.) stirring solution, followed immediately by tri-n-butylamine (3 mL). After 1 minute, 1 M triethylammonium hydrogen carbonate buffer (100 mL) was added and stirring was continued for 30 minutes. The reaction solution was diluted to 3 L with deionized water and applied to a 1.1×7.0 cm DEAE Sepahadex A25 (Aldrich) ion exchange chromatography column which had been washed with 1.0 M ammonium bicarbonate and preequilibrated with deionized water. The title compound was eluted with a 0 to 0.5 M gradient (4 L) of ammonium bicarbonate. The appropriate fractions were combined and the volatiles removed by evaporation in vacuo, redissolved in water and evaporated again to give the ammonium salt of the title compound (0.37 mmol, 37%); UV (0.1 M HCl)λ max=260 nm. UV purity (254 nm detection) was 100% by analytical strong anion exchange HPLC (Whatman Partisil 5, SAX RAC II, 0.05 M to 0.95 M gradient with ammonium phosphate buffer (pH 5.5), 5% methanol). 1H-NMR (D2O) δ 8.06 (s, 1H), 8.05 (s, 1H), 6.13–6.21 (m, 1H), 5.82–5.88 (m, 1H), 5.45–5.53 (m, 1H), 3.76–3.90 (m, 2H), 3.02–3.16 (br m, 1H), 2.64–2.78 (m, 1H), 1.52–1.64 (m, 1H); 31P-NMR (D2O) −9.90 (d, 1P, J=20.3 Hz), −10.84 (d, 1P, J=20.3). Mass spectrum (ES−) m/e 390 (M−H).

Provenance & Evidence