Council of Scientific and Industrial Research

Abdul R Deshmukh

Srinivasachari Rajappa

Rajan Hiralal Naik

Sagun Kashinath Tandel

Baburao Manikrao Bhawal

Vasudeo P Shiralkar

A process for the preparation of an S-alkyl ester of an N-alkyl carbamothioic acid having the formula: ##STR1## wherein R and R.sub.2 are each an alkyl group and R.sub.1 is hydrogen or alkyl, which includes refluxing the corresponding alkyl ester of N-alkyl thiocarbamio acid having the formula I ##STR2## wherein R and R.sub.2 are each alkyl and R.sub.1 is hydrogen or alkyl, in the presence of an acid catalyst selected from the group consisting of iodine and sulfuric acid.

Pesticidal ester preparation

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.

Process for making alkyl N-alkyl or N-aryl-thiocarbamates

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.

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Maharashtra, India

Abdul R Deshmukh