Studies On The Acylation And Ring-Opening Of Two Benzoriazole Derivatives

Benzotriazole (BtH), which is low-cost, non-toxic and stable in nature, is an ideal auxiliary reagent in organic synthesis. It's easy to introduce the benzotriazolyl (Bt) into a variety of compounds through the addition and condensation reaction. The benzotriazole derivatives thus prepared are usually crystalline solids, easy to separate and purify. The introduction of benzotriazolyl group can increase the reactive centre. And after the desired reaction, it can be removed through suitable means since it bears good leaving ability. Besides, the benzotriazole can be recovered almost quantitatively and get reused. The dissertation investigated two types of benzotriazlole derivatives, namely, N-acylbenzotriazoles and bisbenzotriazolyl compounds. The methods for the synthesis and application of the two types of benztoraizole derivatives were discussed. The dissertation thus includes two parts:Firstly, with a variety of N-acylbenzotriazole as the substrates, the acylation reaction of sodium azide was studied. It was found that the reaction can proceed highly efficient at room temperature with FeCl3·6H2O as a catalyst. The prepared acyl azides underwent Curtius re-arrangement in the presence of benzotriazole and afforded the carbomoyl benzotriazoles. in good to excellent yields. The carbamoyl benzotriazoles are crystalline and non-moisture sensitive compounds. It can be used as a stable isocyanate alternative, which has been demonstrated by the reaction with amines, alcohols and hydrazines to synthesize ureas, carbomyol esters and amino ureas in excellent yields. Part two developed a facile and clean method for the synthesis of bis(benzotrizaol-1-yl)arylmethanes and (benzotriazo-1-yl)(benzotriazol-2-yl)arylmethane-s by condensation of 2 eq. benzotriazole and 1 eq. aldehyde in refluxed toluene with PTSA as a catalyst.3-Aryl-1,2,4-benzotriazine was obtained unexpectedly by the reaction of the bis(benzotrizaol-1-yl)methylarenes with allylsamarium bromide via ring-opening of bis(benzotrizaol-1-yl)methylarenes, and a reasonable free radical mechanism was proposed.