Studies of heterocyclic compounds. Part 24. Syntheses of 6aλ4-thia-1,2,6-triazapentalenes

Abstract

6aλ⁴-Thia-1,2,6-triazapentalenes, a new class of four-electron three-centre bonded compound, have been synthesised by the reaction of 1-aryl-6,6aλ⁴-dithia-1,2-diazapentalenes in dimethylformamide with ethanolic methylamine; by S(6)-methylation of 1-aryl-6,6aλ⁴-dithia-1,2-diazapentalenes with methyl fluorosulphonate and treatment of the resulting 2-aryl-5-(2-methylthiovinyl)-1,2,3-thiadiazolium fluorosulphonates with methylamine; and by the coupling of 1,3,4,6-tetra-alkyl-6aλ⁴-thia-1,6-diazapentalenes with arenediazonium tetrafluoroborates and concomitant elimination of a methyliminomethyl group. 3,4-Dialkyl-6aλ⁴-thia-1,2,6-triazapentalenes react with benzenediazonium tetrafluoroborate to give 3,4-dialkyl-1,6-diphenyl-6aλ⁴-thia-1,2,5,6-tetra-azapentalenes.