Comparison of conventional and microwave-assisted synthesis of some new sulfenamides under free catalyst and ligand


Yakan H., Kütük H.

MONATSHEFTE FUR CHEMIE, vol.149, no.11, pp.2047-2057, 2018 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 149 Issue: 11
  • Publication Date: 2018
  • Doi Number: 10.1007/s00706-018-2261-4
  • Journal Name: MONATSHEFTE FUR CHEMIE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2047-2057
  • Keywords: Sulfenamides, Thiophthalimides, Sulfur transfer reagent, 2-Ethoxyethanol, Microwave heating, RADICAL-SCAVENGING ACTIVITY, SULFUR-NITROGEN BOND, ORGANIC-SYNTHESIS, DISULFIDES, CHEMISTRY, DERIVATIVES, SOLVENT, AMINES, MECHANISMS, REAGENTS
  • Ondokuz Mayıs University Affiliated: Yes

Abstract

Sulfenamide and its derivatives (S-N bond) have been synthesized with classical method in the literature. However, microwave-assisted synthesis of a series of N-(substituted phenylthio), N-(benzylthio), N-(cyclothio), and N-(2-mercaptobenzimidazolyl)amines has been not in the literature yet. They have been obtained from treating some amines (4 mmol) with thioph-thalimides (PhthSR, 1 mmol) using sulfur transfer reagent in the presence of 2-ethoxyethanol (beta-ee, neat) under microwave irradiation at 50 degrees C. The scope of this reaction was shown by the efficient synthesis of sulfenamides in good to excellent yields of 70-98% under free catalyst and ligand. Nine of the synthesized sulfenamide derivatives are novel. All of the thiols react with morpholine to give corresponding sulfenamides in excellent yields of 78-98%. Thiophenol, 4-methylthiophenol, 4-chlorothiophenol, and 4-fluorothiophenol react with cyclohexylamine to give corresponding sulfenamides in high yields 81-92%. Thiophenol, 4-methylthiophenol, 4-chlorothiophenol react with pyrrolidine to give corresponding sulfenamides in good yields of 70-76%. We observed that the reaction of t-butylamine with N-(phenylthio)phthalimide gave desired sulfenamide under microwave irradiation in the presence of DPPH as radical scavenger reagent in high yield of 93% Aniline, benzylamine, 1-hexylamine, ethanolamine, diethylamine, N-ethyl-n-butylamine, N-ethylaniline, N-benzylmethylamine, t-butylamine react with thiols to give symmetrical disulfides instead of desired products under microwave irradiation, 2-ethoxyethanol as a solvent (neat), and at 50 degrees C. In this study, microwave-assisted synthesis method was compared with the classical method. All the products obtained were purified with chromatographic method and the analysis of these products was confirmed with IR, H-1 NMR, C-13 NMR spectroscopy, MS spectrometry, and elemental methods.