Cyclocondensation of N-prop-2-ynyl-and N-pentadiynyl- o-phenylenediamines with phenyl isothiocyanate.

Cyclocondensation of N-prop-2-ynyl-o-phenylenediamine with phenyl isothiocyanate leads to the formation of 1-(3-arylprop-2-ynyl)-2,3-dihydro-1H-benzimidazole-2-thiones. In the reactions of diacetylene derivatives — N-penta-2,4-diynyl-o-phenylenediamine — with phenyl isothiocyanate the formation of two heterocyclic nuclei occurs simultaneously to form [1,3]thiazolidino[3,2-a]benzimidazoles. [ABSTRACT FROM AUTHOR]