Abstract: A process for the preparation of alkyl esters of N-alkyl or N-aryl thiocarbamic acid having the formula: ##STR1## wherein R is alkyl or aryl, R.sub.2 is alkyl and R.sub.1 is hydrogen or alkyl which comprises reacting the S-alkyl ester of N-alkyl or aryl dithiocarbamic acid having the formula: ##STR2## wherein R, R.sub.1, R.sub.2 have the meanings stated above with an appropriate alkali metal alkoxide in the presence of one or more alcoholic solvents.

Abstract: A process is disclosed for the manufacture of 1-substituted amino-1-substituted thio-2 nitro alkenes of the general formula: (R1NH) (R2S) C.dbd.CR3 (NO2) wherein R1, R2, R3, may be same or different and may consist of hydrogen, alkyl, aryl or arylalkyl groups or combinations thereof. These alkenes are prepared by reacting a primary amine with a compound of sulfur in the presence of a primary catalyst to obtain a carbonimidodithioic acid salt which is converted to a corresponding ester which is thereafter reacted with a nitro compound in the presence of a secondary catalyst. 1-methylamino-1-methylthio-2-nitroethene is an important intermediate in the synthesis of Rantitidine and Nizatidine which are used as effective drugs in the treatment of peptic ulcers and associated gastrointestinal disorders.