Phenylenediamine and 4,4′-diaminodiphenyls in cyclothiomethylation with CH2O and H2S

Cyclothiomethylation of o-phenylenediamine with CH2O and H2S gives rise to 1,2,4,5-tetrahydrobenzo[d][1,3,6]thiadiazepine and 1,2,6,7-tetrahydrobenzo[f][1,3,5,8]dithiadiazonine, whereas m-phenylenediamine forms benzothiaza macroheterocycles of various structure, comprising 4–8 molecules of the starting diamine, formaldehyde, and hydrogen sulfide. 4,4′-Diaminodiphenyls give bis(1,3,5-dithiazinanes), along with oligomeric hetero(N,S,O)atomic compounds.