Prepn. of di:thioalkyl unsatd. intermediates - from carbon di:sulphide with nitromethane or cyanamide, followed by alkylation

摘要

Dithioalkyl unsatd. cpds. of formula R1 - Z= C (SR2)2 (I) (where R1 = an electronegative gp. such as CN or NO2; Z = CH or N; R2 = 1-7C alkyl) are prepd. by treating a cpd. of formula R1 - ZH2 (II) with CS2 in an aq. medium at a temp. below 30 deg.C, then adding an aq. soln. of a mineral base to adjust the mixt. to pH 8-12, adding an alkylating agent (R2)n -X (III) (where n = 1 or 2; X = halogen or sulphate) and recovering the ppte. Cpds. (I) are intermediates for pharmaceuticals, esp. Cimetidine and Ranitidine.