Mild and Efficient Condition for Synthesis of Gabapentin Impurity B and E

Gabapentin (1), a widely prescribed anticonvulsant used to treat epilepsy and neuropathic pain. This work describes the synthesis of two potential Gabapentin impurities as per USP and EP. Gabapentin impurity B; 2-(1-cyanocyclohexyl) acetic acid (2) was synthesized by oxidative dehydrogenation of Gabapentin API using trichloroisocyanuric acid. Impurity E; 1-(carboxymethyl) cyclohexanecarboxylic acid (3) was obtained by acid hydrolysis of 2. These impurities are characterized by IR, mass spectral data, HPLC RRT and 1 H NMR