Citric acid mediated green synthetic route has been demonstrated for the regioselective synthesis of N-alkylated indazoles in good to excellent isolated yields ( ~ 78-96%) from readily available starting materials 2-methylanilines (1), NaNO2 (2) and ethyl chloroacetate (3) via diazotization, intra molecular cyclization and followed by N-alkylation in the presence of 1:1 ratio of ethanol and water in one-pot. Notably, if the substrate (1) contains – NO2 group and is reduced to – NH2 in the presence of Fe, CaCl2 in the same pot at 60-65°C for 30-40 min. The remarkable advantages of this method include cleaner reaction profile, easy to perform, high yields of products and simple work-up procedure. Besides, the reaction is step-and atom-economic and is carried out in green catalytic medium.
Trivikram Reddy G, Venkatesh MV, Reddy Bodireddy Mohan and Gangi Reddy NC1
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