Acetylthiourea → HCID 13175939, compound

Participants

Reaction Conditions

Reaction Steps

A solution of acetylthiourea (1.8 g) in dry tetrahydrofuran (20 cc) is added, in 5 minutes, to a solution, cooled to 3° C., of the mixture of the epimers of 2-benzhydryloxycarbonyl-7-t-butoxycarbonylamino-3-(1-bromo-2-oxoethyl)-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (5.87 g) in dry tetrahydrofuran (58.7 cc). The reaction mixture is then stirred for 4 hours 30 minutes at 25° C. after which it is diluted with ethyl acetate (150 cc) and saturated sodium bicarbonate solution (150 cc). The organic layer is washed with distilled water (2×100 cc) and then with saturated sodium chloride solution (100 cc) and dried. After evaporation of the solvent under reduced pressure (30 mm Hg; 4 kPa) at 30° C., the residue is chromatographed on a column (height: 30 cm; diameter: 6 cm) of silica (0.04-0.06 mm), elution being carried out under a pressure of 0.4 bar (40 kPa) with a 70:30 (by volume) mixture (1600 cc) of cyclohexane and ethyl acetate and then with a 30:70 (by volume) mixture (2000 cc) of cyclohexane and ethyl acetate, 100 cc fractions being collected. Fractions 27 to 33, containing the pure product, are combined and evaporated to dryness. 3-(2-Acetylamino-thiazol-5-yl)-2-benzhydryloxycarbonyl-7-t-butoxycarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (0.54 g) is obtained in the form of a yellow froth.

Provenance & Evidence