784-41-8

2-Amino-5-chloro-4'-hydroxybenzophenone is an intermediate in the preparation of Diazepam (D416855), an anxiolytic agent, muscle relaxant and anticonvulsant agent.

Preparation by cleavage of 5-chloro-3-(phydroxyphenyl)- 2,1-benzisoxazole (other name: 5-chloro-3-(p-hydroxy-phenyl)anthranil) (SM),
? by heating at reflux with aluminium iodide for 50 min (87%);
? by reaction with concentrated hydrochloric acid and an excess of tin in boiling ethanol or acetic acid. SM (m.p. 241°) was prepared by condensation of o-nitrobenzaldehyde with phenol in the presence of hydrogen chloride or phosphorous oxychloride in cold acetic acid;
? by hydrogenation in the presence of 10% Pd/C in ethyl acetate between 40° and 60° at a pressure of 3 atmospheres (quantitative yield).