Rabeprazole Impurity G

Rabeprazole Impurity G is a degradation byproduct formed via demethylation of the pyrimidine ring in the parent drug, resulting in a fused pyridine-sulfinyl-pyrimidin-2-yl-thiazole core. The structure retains the 3-(4-methoxyphenyl) moiety but lacks the 1-methyl substitution, introducing a pyrimidine-2-yl linker. Key functional groups include the sulfinyl bridge, thiazole heterocycle, and methoxy aromatic substituent. This impurity serves as an HPLC reference standard for quantifying process-related degradation in rabeprazole formulations.