Pyridine → 5'-O-[2-(2-nitrophenyl)propyl-sulfonyl]-thymidine

Participants

Reaction Conditions

Reaction Steps

242 mg thymidine (1 mmol, co-evaporated 3× each with 5 ml abs. pyridine) are dissolved in 2.5 ml abs. pyridine and cooled to -60° C. 396 mg 2-(2-nitrophenyl)propylsulfonyl chloride (1.5 mmol) in 2.5 ml abs. CH2Cl2 are added drop-wise to this within 10 Min. After stirring 4 h at a temperature between -60 and -30° C., the temperature is allowed to increase to -15° C. After a total of 61/4 h, the reaction is mixed with 15 ml H2O and CH2Cl2 respectively and the aqueous phase is extracted 4× each with 15 ml CH2Cl2. The combined organic phases are dried over Na2SO4, filtered and rotary evaporated. This is co-evaporated 3× with toluene and 1× with methanol. The crude product (600 mg) is purified over flash chromatography (39 g silica gel, 3×11 cm, Sol.: CH2Cl2 /MeOH, cond.: CH2Cl2, gradient: 100 ml CH2Cl2, each 150 ml 100:1, 100:2, 100:3 and 100:4). 290 mg (0.62 mmol, 62%) 5'-O-[2-(2-nitrophenyl)propyl-sulfonyl]-thymidine are obtained as a colorless foam. The obtained mixed fractions are purified by a further column (4.5 g silica gel, 1×11 cm, Sol.: CH2Cl2 /MeOH, cond.: CH2Cl2, gradient: 100 ml CH2Cl2, each 50 ml 100:0.5, 100:1 and 100:2). 128 mg (0.18 mmol, 18%) 3',5'-Di-O-[2-(2-nitrophenyl)-propylsulfonyl]-thymidine are isolated as a colorless foam and 26 mg (0.06 mmol, 6%) 3 '-O-[2 -(2-nitrophenyl)-propylsulfonyl]-thymidine as a light red foam.

Provenance & Evidence