[Background and Overview][1][2]
4-Methoxybenzo[D]oxazole-2(3H)-thione, the English name is 4-methoxy-3H-1, 3-benzoxazole-2-thione, CAS number is 1246471-39- 5. The molecular formula is C8H7NO2S, molecular weight 181.21200; PSA: 74.06000; LogP: 2.12510.
If 4-methoxybenzo[D]oxazole-2(3H)-thione is inhaled, move the patient to fresh air; if skin contact occurs, remove contaminated clothing and wash with soap and water. Rinse skin thoroughly with water and seek medical attention if you feel discomfort. If eye contact occurs, separate eyelids, rinse with running water or saline, and seek medical attention immediately. If ingested, rinse mouth immediately. Do not induce vomiting and seek medical attention immediately. Advice to protect rescuers is as follows: Move the patient to a safe place, consult a doctor, and if conditions permit, please show this chemical safety data sheet to the doctor who comes to the scene. If there is a small leak, collect the leaked liquid in a sealable container as much as possible, absorb it with sand, activated carbon or other inert materials, and transfer it to a safe place. Do not flush it into the sewer; if there is a large leak, build a dike or dig a pit. Contain, seal the drainage pipe, cover it with foam to inhibit evaporation, use an explosion-proof pump to transfer it to a tanker or a special collector, and recycle or transport it to a waste treatment site for disposal.
[Structure][7]
[Application][2]
4-Methoxybenzo[D]oxazole-2(3H)-thione can be used as a pharmaceutical intermediate to synthesize other compounds with certain activity, but its application has been rarely reported. The analog of 4-methoxybenzo[D]oxazole-2(3H)-thione [5-methoxybenzo[d]oxazole-2(3H)-thione] is omeprazole Key intermediate impurity, omeprazole is the first-generation benzimidazole gastric acid proton pump inhibitor developed by Swedish Astra Zen-eca Company. It is mainly used to treat peptic gastric ulcer and reflux gastritis. According to the “European Pharmacopoeia EP8.0”, there are 9 known impurities in omeprazole (A ~ I, Chart 1): Impurity A is the key intermediate of omeprazole 5-methoxy-1H-benzo [d] Imidazole-2-thiol, impurities B to I are process impurities and degradation impurities of omeprazole. Using 4-methoxy-2-nitroaniline as raw material, impurity A was synthesized through a two-step reaction of nitro reduction and carbon disulfide ring closure. The reaction process is as follows:
[References]
[1]http//baike.molbase.cn/cidian/1719859?search_keyword=1246471-39-5&page=1&per_page=10
[2] Wang Chuan, Zhou Mingqiang, Huang Wencai. Isolation and structure confirmation of the key intermediate impurity of omeprazole [5-methoxy-benzo[d]oxazole-2 (3H)-thione] [J]. Synthetic Chemistry, 26(4): 284-287.
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