A solution of 5-[3-(2-trifluoroacetamidoethoxy)propynyl]-2'-deoxyuridine (3.4 g, 8.1 mmol) in methanol (20 ml) is stirred with ammonium formate (prepared by addition of 3 ml, 79 mmol of cold 98% formic acid into 2 ml, 50 mmol of dry ice frozen 25% ammonia) and 0.2 g of 10% Pd/C for 7 hours at room temperature under hydrogen atmosphere. The catalyst is removed by filtration, the filtrate evaporated and product is purified on LiChroprep RP-18 column by the above procedure. Fractions containing the desired product are combined and evaporated to dryness in vacuo and the resultant solid is triturated with dry ether to give 3.0 g (87% product, m.p. 107-110°; max in nm, in 0.1M triethylamine-acetate (pH 7.5), 220, 268. Analysis calculated for C16H22F3N3O7 : C, 45.18; H, 5.21; N, 9.88; F, 13.40. Found C, 45.16; H, 5.16; N, 9.68; F, 13.13.
