The synthesis of potential insecticides. Part I. 2,2-Dichlorovinyl carbamates and carbonates

Abstract

In contrast to the zinc-dust reduction of 1-alkylthio-2,2,2-trichloroethyl carbamates, which gives mainly 2,2-dichlorovinyl alkyl sulphides by an elimination–fragmentation reaction, zinc-dust reduction of 1-alkylsulphonyl-2,2,2-trichloroethyl carbamates affords good yields of the novel 2,2-dichlorovinyl carbamates. A similar reaction sequence has been applied to the preparation of 2,2-dichlorovinyl carbonates. 1-Alkylsulphonyl-2,2,2-trichloroethyl dimethylcarbamates also gave the corresponding 1-alkylsulphonyl-2,2-dichlorovinyl dimethylcarbamates by their reaction with triethylamine. The 2,2-dichlorovinyl carbamates did not inhibit crude enzyme preparations of acetylcholinesterase.