Roxatidine acetate


Roxatidine acetate is a specific and competitive histamine H2 receptor antagonist drug that is used to treat gastric ulcers, Zollinger–Ellison syndrome, erosive esophagitis, gastro-oesophageal reflux disease, and gastritis.
Pharmacodynamic studies showed that 150 mg of roxatidine acetate were optimal in suppressing gastric acid secretion, and that a single bedtime dose of 150 mg was more effective than a dose of 75 mg twice daily in terms of inhibiting nocturnal acid secretion.
It was patented in 1979 and approved for medical use in 1986. It is available in countries including China, Japan, Korea, Germany, Italy, the Netherlands, Greece, and South Africa.

Synthesis

The reductive amination between piperidine and 3-hydroxybenzaldehyde gives 3-phenol. Williamson ether synthesis with N-phthalimide gives the intermediate 5. Deprotection with hydrazine yields propylamine. Heating with glycolic acid provides roxatidine which is then converted to its acetate ester, roxatidine acetate, by acetylation with acetic anhydride.