NOVEL HETEROPENTALENES - SYNTHESIS OF THE NABAM OXIDATION-PRODUCT AND RELATED-COMPOUNDS

5,6-Dihydroimidazo[2,1-c][1,2,4]dithiazole-3-thione [the oxidation product of disodium ethylenebis(dithiocarbamate)] and analogues containing reduced pyrimidine and benzimidazole rings have been synthesised by the action of carbon disulphide on (benzylthio)isothiourea and phenacylisothiourea derivatives of cyclic thioureas. Similar reactions with phenyl isothiocyanate and other heterocumulenes lead to the novel heteropentalenes, 2,3,4,5-tetrahydro-2,5- bis(phenylimino)-3,4-ethano-1,6,6aλ4-trithia-3, 4-diazapentalene, 2,3,4,5-tetrahydro-1,6-diphenyl-3,4-propano- 6aλ4-thia-1,3,4,6-tetra-azapentalene-2,5-dithione, the corresponding 2,5-dione, and 2,3,4,5-tetrahydro-1,6-dimethyl-3,4-propano- 6aλ4-thia-1,3,4,6-tetra-azapentalene-2,5-dithione.