Environmental chemistry 2020 -Citric acid Mediated One-pot Regioselective Synthesis of N-Alkylated Indazoles An Efficient Green Strategy Trivikram Reddy G1- Yogi Vemana University

摘要

Citric acid mediated green synthetic route has beendemonstrated for the regioselective synthesis of N-alkylatedindazoles in good to excellent isolated yields ( ~ 78-96%) fromreadily available starting materials 2-methylanilines ,NaNO2and ethyl chloroacetate via diazotization, intra molecularcyclization and followed by N-alkylation in the presence of 1:1ratio of ethanol and water in one-pot. Notably, if the substrate(1) contains – NO2 group and is reduced to – NH2 in thepresence of Fe, CaCl2 in the same pot at 60-65°C for 30-40min. The remarkable advantages of this method includecleaner reaction profile, easy to perform, high yields ofproducts and simple work-up procedure. Besides, the reactionis step-and atom-economic and is carried out in green catalyticmedium. Keywords: Citric acid; o-Toluidines; Ethylchloroacetate; Regioselectivity; N-Alkylated Indazoles.Heterocyclic ring systems are frequently found in numerousnaturally occurring compounds and they compose the corestructures of many biologically active motifs as well as someindustrial compounds.