Thymidine → 5'-O-tert-Butyldiphenylsilyl-thymidine

Participants

Reaction Steps

A mixture of thymidine (400 g, and 1.65 mol), 4-dimethylaminopyridine (0.8 g, 6.5 mmol) and t-butyldiphenylchlorosilane (347.2 g, 1.26 mol) in anhydrous pyridine (3.0 lt) was stirred at room temperature for 48 hr. To the stirred reaction mixture two lots of t-butyldiphenyl chlorosilane (129.4 g, 0.47 mol and 22.7 g, 0.082 mol) were added 12 hr. apart and stirring continued for an additional 48 hr. The reaction mixture was concentrated under vacuum and the residue redissolved in methanol (2.5 lt). The product was precipitated by pouring the reaction mixture into a cold stirred ice-water (5.0 lt) suspension. The aqueous suspension was stirred at room temperature for 3 hr. to quench traces of unreacted chlorosilane. The granular white precipitate was filtered and washed with distilled water (5×1 lt) and air dried to furnish 876 g of 5'-O-t-butyldiphenylsilyl thymidine (slightly contaminated with bissilyated product, about 5%). The impurity was removed by suspending finely powdered 5'-O-t-butyldiphenylsilyl thymidine in ether (600 ml) and pouring into stirred hexanes (1.5 lt).

Provenance & Evidence