4-Desmethoxy Omeprazole Sulfide

4-Desmethoxy Omeprazole Sulfide is an API impurity derived from Omeprazole via demethylation at the 4-position of the pyridine ring and reduction of the sulfinyl group to a sulfide. This compound retains the core benzimidazole scaffold and pyridine moiety characteristic of proton pump inhibitors but features a sulfur atom bridging the pyridine and phenolic ring, replacing the parent’s sulfinyl functionality. The absence of the 4-methoxy group introduces a hydroxyl-exposed site, enhancing susceptibility to oxidative degradation pathways. Structurally, it serves as a critical intermediate in elucidating Omeprazole’s metabolic stability and synthetic pathway optimization. This compound functions as an HPLC reference standard for quantifying process-related impurities in Omeprazole formulations.