STEPWISE SYNTHESIS OF TRI SUBSTITUTED 1, 2, 4-TRIAZOLES BY OXIDATIVE AROMATIZATION VIA CASCADE FUNCTIONALIZATION
PERVARAM KAVITHA
Department of Chemistry Chaitanya Deemed to be University Warangal Urban, Telangana, India.
JAGADEESH KUMAR EGA
Department of Chemistry Chaitanya Deemed to be University Warangal Urban, Telangana, India.
KAVITHA SIDDOJU *
Department of Chemistry Chaitanya Deemed to be University Warangal Urban, Telangana, India.
*Author to whom correspondence should be addressed.
Abstract
In this work, we described the two-step synthesis of Tri-substitutedtriazoles using microwave irradiation technique with ferric chloride as catalyst. The acid catalyzed reaction between hydrazine 1 with various aromatic aldehydes (2a-d) in ethanol as a solvent gave desired hydrazones (3a-3d followed by elimination process by losing water in the first step. In the second step, conventional and microwave synthesis of 1,2,4-triazoles proceeds through a cascade C−H functionalization, C−N double bond formation, and oxidative aromatization sequence. Hydrazones (3a-3d) underwent cyclization with aliphatic amines (4e & 4f) in CH3CN in the presence of a catalyst I2 and mild oxidizing agent t-butyl hydro peroxide/ H2O2 and the reaction mixture was stirred at 900 °C for 4 hr or under microwave irradiation using silica gel supported by ferric chloride (SiO2-FeCl3) to afford pure 1,2,4-triazole derivatives 5ea-5ed & 5fa-5fd shown in Scheme 1and Table 1.
Keywords: 1,2,4-triazoles, hydrazones, oxidative aromatization, cascade reaction, conventional method and MWI