Estudo das reações de condensação de espiroepoxicetonas e 2-arilideno-1-tetralonas derivadas da α-tetralona com aminoguanidina

Abstract

The aim of this work is studying the condensation reactions of spiroepoxyketones and 2-arylidene-1-tetralones derived from α-tetralone with aminoguanidine hydrochloride. In a first step, the 2-arylidene-1-tetralones were obtained with excellent yields by aldol condensation reaction between the α-tetralone and aromatic aldehydes. In the next step, the spiroepxyketones were obtained in good yields from the epoxidation reaction of the 2-arylidene-1-tetralones with hydrogen peroxide under alkaline conditions. In a third step, the cyclocondensation between aminoguanidine hydrochloride and spiroepoxyketones was carried out to obtain benzoindazole. Due to difficulties found in the purification of the benzoindazole the cyclization starting from 2-arylidene-1-tetralone was performed to obtain the dihydrobenzoindazole. These cyclizations resulted in mixtures of dihydrobenzoindazoles and hydrazones or pure hydrazones depending on the electronic effect of the substituents. In this sense, the electron donors substituents favor the formation of the hydrazone intermediate and, in contrast, electron-withdrawing substituents favor the cyclization to dihydrobenzoindazole. The proportions of these products were determined by 1H NMR. The products obtained in pure form were characterized by infrared spectroscopy, mass spectrometry, melting point, 1H NMR and 13C NMR and showed consistent data with their structures.