Reactions of Aldonitrones with Phenylphosphonothioic Dichloride and Related Compounds. Formation of 2-Arylbenzothiazoles from α,N-Diarylnitrones

Article abstract of DOI:10.1246/bcsj.55.870

Reactions of α-aryl-N-methylnitrones with phenylphosphonothioic dichloride (1), diphenylphosphinothioic chloride (6), or thiophosphoryl trichloride (7) gave N-methylbenzamide and N-methylthiobenzamide derivatives, and the latter became major in the presence of tertiary amine. α,N-Diarylnitrones (4) reacted with 1 to give 2-arylbenzothiazoles (5) at room temperature in moderate yields.Reaction of 4 with 6 (at room temperature) or 7 (in refluxing THF) gave 5 in a low yield, whereas a similar reaction of 4 with 7 at 0 deg C afforded N-benzylidene-2-chloroaniline in a high yield.A mechanism for the formation of 5 has been discussed briefly.