Pyridine → Carbonic acid (1S,4R)-4-[2-chloro-6-(2,2-diphenyl-ethylamino)-purin-9-yl]-cyclopent-2-enyl ester ethyl ester

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Reaction Steps

(1S,4R)-4-[2-Chloro-6-(2,2-diphenyl-ethylamino)-purin-9-yl]-cyclopent-2-enol (3.00 g, 6.95 mmol) is placed in an oven-dried flask under an atmosphere of argon. Dry THF (100 ml) is added followed by dry pyridine (1.10 g, 13.90 mmol). Ethyl chloroformate (3.02 g, 27.80 mmol) is added slowly and the reaction mixture is stirred at room temperature. The reaction is shown to be complete by TLC after 4 hours. The solvent is removed in vacuo and the residue is partitioned between dichloromethane (200 ml) and 10% citric acid (200 ml). The organic layer is washed with water (150 ml) and brine (150 ml), dried over MgSO4, filtered and the solvent is removed in vacuo. The title compound is obtained after purification by flash column chromatography (silica, iso-hexane/ethyl acetate 2:1). 1H nmr (CDCl3, 400 MHz); 7.70(br s, 1H), 7.35-7.15(m, 10H), 6.35(m, 1H), 6.15(m, 1H), 5.80(m, 1H), 5.65(m, 2H), 4.35(t, 1H), 4.25(m, 2H), 4.20(q, 2H), 3.10(m, 1H), 1.95(d, 1H), 1.30(t, 3H), MS (ES+) m/e 504 (MH+).

Provenance & Evidence