Dimethyl Sulfoxide → HCID 19099323, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of oxalyl chloride (23 ml) in dichloromethane was added dropwise dimethyl sulfoxide (374 ml) while keeping the temperature below -50° C. After the mixture was stirred for 30 minutes at -50° C.~-60° C., 1.2-bis(benzyloxycarbonyl)-4-(1-hydroxyethyl)pyrazolidine (675 g) was added dropwise below -50° C. After the mixture was stirred for 45 minutes at -50° C.~-60° C., triethylamine (122 ml) was added dropwise below -50° C. The reaction mixture was allowed to warm to 0° C. and quenched with water (500 ml). The aqueous layer was separated and extracted twice with dichloromethane (200 ml×2). The combined organic layer was washed with 1N hydrochloric acid (200 ml×2), saturated sodium bicarbonte (200 ml), and 5% sodium chloride (200 ml), dried over magnesium sulfate, and evaporated under reduced pressure. The residue was chromatographed on silica gel (820 ml, hexane:ethyl acetate=2:1~1:1) to give 1,2-bis(benzyloxycarbonyl)pyrazolidin-4-yl methyl ketone (61.5 g).

Provenance & Evidence