Abstract An efficient and simple oxidative protocol has been developed for the preparation of pyrazoles from pyrazolines mediated by TBHP/Cu(OAc)2 at room temperature. The present protocol has been successfully applied for the preparation of various pyrazole compounds from heterocyclic pyrazolines.
The visible light mediated oxidation of 1,3,5-trisubstitutedpyrazolines under metal-free conditions was developed. Various substituted pyrazolines were oxidized to pyrazoles by irradiation with visible light/sunlight. A plausible mechanism was proposed for the light mediated oxidation proceeding via formation of intermediates with electron rich C-3 positions and electron deficient C-5 positions. Correlation
alkene (styrene) was investigated as the dipolarophile. Over 30-fold improvement in quantum yield of the reactionproduct was achieved in aqueous solution. According to our mechanistic studies, the observed improvement is likely due to an insufficient protonation of the styrene–tetrazole reactionproduct. This finding provides useful guidance to the future design of alkene–tetrazole reactions for biological
aryl rings. In addition, the effects of the concentration and the solvent polarity on the fluorescence emission were studied. Density functional theory (DFT) calculations were carried out to gain insight into the geometric, electronic, and spectroscopic properties of the pyrazoline derivatives. The results of both experimental and computational studies explain the effects of the geometrical orientation