Trends in der grünen Chemie Offener Zugang

Abstrakt

Citric acid Mediated One-pot Regioselective Synthesis of N-Alkylated Indazoles: An Efficient Green Strategy

Trivikram Reddy G, Venkatesh MV, Reddy Bodireddy Mohan and Gangi Reddy NC1

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.