Cilostazol related compound C

Cilostazol related compound C is a thienopyridine-based impurity arising from a synthetic pathway deviation in cilostazol production. It retains the core thienylpyridine scaffold but features an extended side chain incorporating a substituted piperazine ring and a cyclopropylmethyl ether moiety. The molecule exhibits three stereocenters, a tetrazole heterocycle, and an amidine functional group, distinguishing it from the parent drug. Its structural divergence stems from a failed cyclization step during API synthesis, leading to a truncated product with altered pharmacophoric properties. This compound serves as a critical HPLC reference standard for quantifying process-related impurities in cilostazol formulations.