Omeprazole EP Impurity - A

5-Methoxy-2-mercaptobenzimidazole; 1,3-Dihydro-5-methoxy-2H-benzimidazole-2-thione; 2-Mercapto-5-methoxy-1H-benzimidazole; 2-Mercapto-5-methoxybenzimidazole; 5-Methoxy-2-benzimidazolethiol; 5-Methoxy-1H-benzimidazole-2-thiol; 5-Methoxy-1H-benzimidazol-2-thiol (USP); Omeprazole Related Compound B (As per USP Commenting Opening 50(6));