Diethyl (cyanomethyl)phosphonate → 4-(2,3-Dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol-2-yl)-1-cyano-2-methylbut-1-ene

Participants

Reaction Steps

9.5 g (54 millimoles) of diethyl cyanomethyl phosphonate and 8.7 g (48 millimoles) of 30% strength sodium methylate were simultaneously added dropwise to 10.0 g (40 millimoles) of N-(2-oxobut-4-yl)-saccharin in 150 ml of absolute dimethylformamide, while stirring thoroughly. The reaction mixture was stirred for a further 5 hours at 40° C., after which the contents of the flask were poured onto ice-water, and the precipitated crystals were filtered off under suction and recrystallized from ethanol to give 2.2 g (20%) of 4-(2,3-dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol-2-yl)-1-cyano-2-methylbut-1-ene of melting point 117°-118° C.

Provenance & Evidence