Dimethyl Sulfone → tert-Butyl [1-(2-chlorophenyl)-2-(methylsulphonyl)ethyl]carbamate

Participants

Reaction Conditions

Reaction Steps

A solution of 1 g (10.6 mmol) of (methylsulphonyl)methane in 30 ml of THF was cooled to −78° C. and admixed slowly with 6.65 ml of n-butyllithium solution (1.6M in hexane, 10.6 mmol). After 30 min at −78° C., the suspension obtained was added to a solution, cooled to −78° C. beforehand, of 850 mg (3.55 mmol) of the compound from Example 111A in 20 ml of THF. The reaction mixture was stirred at −78° C. for a further 30 min and then slowly warmed to RT. After 30 min, it was cooled to −20° C. again and the reaction was halted by addition of 20 ml of 10% strength aqueous ammonium chloride solution. The mixture was diluted with ethyl acetate. The organic phase was separated and washed twice with water and once with saturated aqueous sodium chloride solution. The organic phase was dried over sodium sulphate, filtered and freed from the solvent on a rotary evaporator. The residue was stirred with 10 ml of methanol/water 10:1 and the solid was filtered off with suction. The slightly yellowish solid was stirred with 20 ml of pentane/isopropanol 5:1, then filtered off with suction again. Drying in an HV gave 800 mg (55% of theory) of the title compound (82% purity according to LC/MS).

Provenance & Evidence