Trifluoromethylated Amidrazone Derivatives as Key Compounds for the Synthesis of 4-Aryl-3,5-bis(trifluoromethyl)-4H-1,2,4-triazoles

Abstract

A novel, efficient, and solvent-free approach for the synthesis of aryl-3,5-bis(trifluoromethyl)-4H-1,2,4-triazoles has been disclosed via the nucleophilic intramolecular cyclization reaction of trifluoromethylated amidrazone and 2,2,2-trifluoroacetic anhydride. Trifluoromethylated amidrazones intermediates which are used in this project have been synthesized from the reaction of N-aryl-2,2,2-trifuoroacetimidoyl chloride derivatives and hydrazine hydrate at ambient temperature in excellent yields.

A Simple and Efficient Approach for the Synthesis of Aryl-3-(trifluoromethyl)-1H-1,2,4-triazol-5(4H)-one Derivatives

“…After removal of the solvent under reduced pressure, the crude product was purified by washing with n-hexane several times. 43 General procedure for the synthesis of compounds 6.…”

“…Following removal of the solvent under reduced pressure, the crude product was purified by washing with n -hexane several times. 42…”

“…zone intermediates 4 via reactions of hydrazine hydrate (3) with trifluoroacetimidoyl chlorides 2 (Scheme 3). 42 Next, en route to the synthesis of 4-aryl-3-(trifluoromethyl)-1H-1,2,4-triazol-5(4H)-one derivatives 7, as a privileged heterocycle core in biologically active molecules, we synthesized ethyl-2 (2,2,2-trifluoro-1-(arylimino)ethyl)hydrazine-1-carboxylate intermediates 6 via reactions of trifluoromethylated amidrazones 4 and ethyl chloroformate (ECF) (5) in the presence of a base and solvent.…”

“…In continues of work, due to the important applications of amidrazone derivatives in the preparation of nitrogen heterocyclic compounds, we synthesized trifluoromethylated amidrazone 4 intermediates from the reaction of hydrazine hydrate 3 with trifluoroacetimidoyl chlorides 2 (Scheme 3). 43 Scheme 3 Synthesis of trifluoroacetimidohydrazides derivatives 4a-l.…”

A Facile and Catalyst-Free Microwave-Promoted Method for the Synthesis of 3-Trifluoromethyl 1,2,4-triazole-5-thiones

“…After the resulting crude product was puri ed by washing with n-hexane several times. [35] General procedure for the synthesis of compounds 6a-n.…”