Synthesis of Some New Heterocycles Derived from Phenylacetyl Isothiocyanate

Abstract

Phenylacetyl 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.

Reactivity and diverse synthetic applications of acyl isothiocyanates

“…27 The reaction of 2-phenylacetylisothiocyanate 1 with benzoylhydrazine in acetonitrile furnished the corresponding thiosemicarbazide 12. The latter compound underwent a dehydrative cyclization in polyphosphoric acid to furnish the 1,2,4-triazoline-5-thione derivative 13 or 13'.…”

“…27 The formation of product 166 was explained through cyclization of the nucleophilic addition product 164 forming the heterocycle 165. The elimination of H 2 S from this heterocycle afforded the final product.…”

Use of Phthalimidoacetyl Isothiocyanate as a Scaffold in the Synthesis of Target Heterocyclic Systems, and Their Antimicrobial Assessment

“…Simultaneous or subsequent cyclization of the obtained adducts gave target heterocyclic systems such as 1,2,4-triazoles, 1,3-diazines, 1,3-oxazines and thiourea attached to a phthalimido moiety. The antimicrobial activity of the synthesized compounds was tested.Key words phthalimidoacetyl isothiocyanate; 1,2,4-triazol; 1,3-diazine; 1,3-oxazine; thiourea; antimicrobial are well known.In the past few years the authors have been involved in the uses of aroyl isothiocyanates [17][18][19][20] and acyl isothiocyanates [21][22][23][24] in different synthetic strategies of target heterocycles. Studies on the chemistry of aroyl and/or acyl isothiocyanates have established the value of these compounds as starting materials in the synthesis of a wide variety of heterocyclic systems and thiourea derivatives.…”

“…In the past few years the authors have been involved in the uses of aroyl isothiocyanates [17][18][19][20] and acyl isothiocyanates [21][22][23][24] in different synthetic strategies of target heterocycles. Studies on the chemistry of aroyl and/or acyl isothiocyanates have established the value of these compounds as starting materials in the synthesis of a wide variety of heterocyclic systems and thiourea derivatives.…”

“…Studies on the chemistry of aroyl and/or acyl isothiocyanates have established the value of these compounds as starting materials in the synthesis of a wide variety of heterocyclic systems and thiourea derivatives. [17][18][19][20][21][22][23][24][25][26][27] Based on the previous work, we have been synthesized variety of heterocyclic systems bearing phthalimido moiety by using 2-phthalimidobenzoyl isothiocyanate 19) and phthalimidoacyl isothiocyanate. 22) In the current study, a further stage reactions of phthalimidoacetyl isothiocyanate was performed.…”