Síntese de 1h-1,2,3-triazol-4-il-1,3,4-oxadiazóis a partir de 4-alcóxi-1,1,1-tricloro-3-alquen-2-onas

Abstract

This work describes the synthesis and the characterization of series of substituted trichloroacetyl 1H-1,2,3-triazoles (10 12), 1H-1,2,3-triazol-4-yl-carbohydrazides (14 16) and 1H-1,2,3-triazol-4-yl-1,3,4-oxadiazoles (18 19), obtained through a synthetic route that contains three reactions steps, having as the initial step, the reaction of 1,3-dipolar cycloaddition between 4-alcoxy-1,1,1-trichloro-3-alken-2-ones (1a,b) and substituted benzyl azides (7 9), like a intermediate step, the haloform reaction between substituted trichloroacetyl 1H-1,2,3-triazoles (10 12) and hydrazine monohydrate (13), and as the final step, the cycloaddition reaction type [4 + 1] between 1H-1,2,3-triazol-4-yl-carbohydrazides (14 16) and triethyl orthoacetate (17). Two 4-alcoxy-l-1,1,1-trichloro-3-alken-2-ones (1a,b) and three substituted benzyl azides (7 9) were employed in the synthesis of substituted trichloroacetyl 1H-1,2,3-triazoles (10 12), resulting in six compounds with yields of 40 to 75 %, all of them having, strategically, the trichloroacetyl substituent in the position 4 of the triazolic ring. Posteriorly, this triazoles (10 12) carried the obtaining of five examples of 1H-1,2,3-triazol-4-yl-carbohydrazides (14 16) through the reactions front hydrazine monohydrate (13), with yields of 73 to 82 %. Finally, the carbohydrazides (14 16) and the triethyl orthoacetate (17) were employed to obtaining of 1H-1,2,3-triazol-4-yl-1,3,4-oxadiazoles (18 19 ), with yields of 65 to 71 %, however, the compound 1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl-carbohydrazide (16) carried the obtaining of a carbazone N -(1-ethoxyethylene)-[1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl]hydrazine (20), with yields of 48 %. The most of this compounds obtained (11 examples) are unpublished. Proving the synthetic versatility of carbohydrazides, the compounds 1-(2,6-difluorobenzyl)-1H-1,2,3-triazol-4-yl-carbohydrazide (14a) and 1,1,1-trifluoro-4- Dissertação de Mestrado Fábio Mulazzani da Luz - 2014 methoxy-4-phenyl-but-3-en-2-one (2) were employed in the synthesis of one example of pyrazolinyltriazolylketone (21), get with a yield of 70 %. This compound is also unpublished. The structural analysis of the compounds were characterized for experiments of 1H, 13C, and mass spectrometry (CG-MS), and them purity determined by elemental analysis.