Hydrochloric Acid → 2,3,4,5-Tetrahydro-1H-benzo(d)azepine

Participants

Reaction Conditions

Reaction Steps

A 350 mL pressure vessel was charged with the methanesulfonic acid 2-[2-(2-methanesulfonyloxy-ethyl)-phenyl]-ethyl ester (3.2 g/10 mmol) in a 1:1 mixture of acetonitrile and ammonium hydroxide (100 mL total volume). The vessel was sealed and heated to 100° C. for one hour (pressure rises to ca. 40 psi) and then gradually allowed to cool. The reaction contents were poured into water and acidified to ca. pH 4 with concentrated hydrochloric acid. The aqueous solution was extracted with diethyl ether (100 mL), basified to pH 14 with 30% aqueous sodium hydroxide and finally extracted repeatedly with 10% methanol/methylene chloride (4×50 mL). The combined organic extracts are dried over magnesium sulfate, filtered and concentrated to afford 2,3,4,5-tetrahydro-1H-benzo[d]azepine as a pale yellow oil (1.2 g/81%) that solidifies on standing. 1H NMR (400 MHz, CDCl3) δ 7.1 (m, 4H), 2.91 (m, 8H).

Provenance & Evidence