DITHIOCARBOXYLATION REACTIONS OF N-CONTAINING C-NUCLEOPHILES

3-Quinuclidinone reacts with carbon disulfide, strong base and an alky lating agent in dipolar aprotic solvents giving 2-dialkylthiomethylene compounds 1. N-acceptor methyl substituted 2,2,N-trimethyl-propionami des afford in this procedure compounds 2-4 and the N-cyanomethyl-N-met hyl-benzamide forms compounds 5. 2-Methyl-benzimidazole leads to the p roduct of N-attack, whereas using 1,2-dibromo-ethane 1,1'-carbonothioy l-bis(2-methyl-benzimidazole) 6 is formed. 2-Chloro-N-cyanomethyl-N-me thyl-benzamide 8 gives on treatment with 2 equivalents of a suitable b ase, carbon disulfide, and an alkylating agent at lower temperatures t he expected substituted ketene dithioacetals 9. At higher temperature the 2-alkylthio-4-methyl-5-oxo-4,5 -dihydrobenzo[f],1,4-thiazepine-3-c arbonitriles 10 are formed. Reaction products have been identified and structurally characterized by X-ray analysis.