N-acylbenzotriazole is a good N-,O-,S-,C-acylation agent comparable to acyl chloride,which can be used for many organic transformations.Benzotriazole(BtH)and thionyl chloride(SOC12)were added to 1,2-dichloroethane.After the benzotriazole was dissolved,carboxylic acid was added and heated to reflux to synthesize various N-acylbenzotriazoles.Taking lauric acid as an example,the reaction factors affecting the synthesis of N-acylbenzotriazole were investigated,and the optimal reac-tion conditions were obtained:carboxylic acid(1.0 eq.),BtH(1.2 eq.),SOCl2(1.2 eq.),1,2-di-chloroethane as solvent,120℃ oil bath heating and refluxing for 6 h,the yield is 94.5%.Then,the substrate was expanded,and thirty-five N-acylbenzotriazole compounds were synthesized under the re-action conditions.The carboxylic acids included aliphatic carboxylic acids,aliphatic diacids,substitu-ted aromatic acids and aromatic diacids,and the yield was basically over 80%.At the same time,the effects of the type and position of aromatic substituents and the length of aliphatic chain on the yield were investigated.The structures of the products were confirmed by 1H NMR and 13C NMR.Under this reaction system,the feed was amplified by 10 times,and the desired product was obtained in a stable,smooth and convenient manner with high yield.In this paper,the reaction was carried out smoothly by changing the solvent and increasing the reaction temperature.In particular,the yield of carboxylic acid and dicarboxylic acid with low solubility was greatly improved,and the amount of benzotriazole was reduced by 2~3 times.Finally,the purification method of some products were opti-mized,which made the purification simpler and more convenient.It provided a new method for the purification of long-chain aliphatic acylbenzotriazole,which made the cost lower and more suitable for industrial production.
N-acylbenzotriazolecarboxylic acidbenzotriazoleacylation reagentindustrial production