SYNTHESIS OF 3-(1-ARYLAMINOCARBONYL-5-AMINO)-1,2,4-TRIAZOLYL BENZYL SULFIDE, SULFOXIDE AND SULFONE

Abstract

3-(1-arylaminocarbonyl-5-amino)-1,2,4-triazolyl benzyl sulfides were synthesized by the reaction of 5-amino-3-benzylthio-1,2,4-triazole and its analogue with the aryl isocyanate. It was found that there was great influence by the property and position of substituents X, Y on the chemical shift of H—N₂ in the ¹H NMR spectra. By means of molecular mechanics calculations, the substituent effect on the chemical shift of H—N₂ was rationalized. The chemocontrolled oxidation of 3-(1-arylaminocarbonyl-5-amino)-1,2,4-triazolyl benzyl sulfide to sulfoxide and sulfone respectively was performed after a careful study of the influence of the concentration of H₂O₂ and the reaction temperature on the oxidation reaction. In ^1H NMR spectra of sulfoxides(II), the protons of a methylene group near the SO chiral center coupled to appear as a quartet in the AB pattern. The SO, SO₂ decreased the electronic density around H—N₂, 5-NH₂, and thus moved the proton absorption to a lower field. The experimental showed that the ratio of sulfoxide(II)/sulfone(III) was influenced by the electronic property of substituents X, Y on the aryl moiety.

Key Words:

• Synthesis
• triazolylbenzyl sulfide
• triazolylbenzyl sulfoxide
• triazolylbenzyl sulfone
• molecular mechanics
• substituent effect
• chemocontrolled oxidation
• ALS enzyme inhibitor