Synthesis of Some New Heterocycles Derived from Phenylacetyl Isothiocyanate

Abstract

AbstractPhenylacetyl isothiocyanate (1) was reacted with benzoyl hydrazine (2a) in acetonitrile to give thiosemicarbazide derivative 3 which was cyclized by polyphosphoric acid to give 1,2,4‐triazoline‐5‐thione derivative 4. Treatment of 1 with thiosemicarbazide (2b) yielded another 1,2,4‐triazoline‐5‐thione derivative 5. Similar treatment of 1 with phenyl hydrazine (2c) in acetonitrile gave a differently substituted 1,2,4‐triazoline‐5‐thione derivative 6 in one pot‐reaction. On the other hand, when the reaction was carried out in acetone, a mixture of 6 and thiadiazolidine derivative 7 was obtained. However, reaction of 1 with hydrazine hydrate (2d) gave hydrazine derivative 8. Reaction of isothiocyanate 1 with anthranilic acid (9) gave benzo[d][1,3,6]oxazin‐1‐one derivative 10. Treatment of 1 with 2‐aminothiophenol (11a), 2‐aminophenol (11b) or o‐phenylenediamine (11c) produced benzothiazole derivative 12a, benzoxazole derivative 12b and benzimidazole derivative 12c, respectively. The structures of all the products were confirmed by micro‐analytical and spectral data.