Metoclopramide → 4-amino-5-chloro-N-(2-(diethylamino)ethyl)-2-hydroxybenzamide hydrochloride

Participants

Reaction Steps

To a cooled (<10°) stirred suspension of sodium hydride (57.44 g of 60%, 1.436 moles) in DMF (1275 ml) was added dropwise a cold solution of ethanethiol (89.22 g, 1.436 moles) in DMF (250 ml). After hydrogen evolution had ceased 4-amino-5-chloro-N-[2-(diethylamino)ethyl]-2-methoxybenzamide (287.0 g, 0.957 moles) (prepared according to U.S. Pat. No. 3,357,978 [1965]) was added and the mixture was heated in an oil bath at 100°-105° for 90 minutes. The solvent was removed in vacuo and the residue partitioned between methylene chloride (800 ml) and water (400 ml). The aqueous layer was washed with another portion of methylene chloride and the combined organic extracts were back-washed with water (150 ml). The combined aqueous phase was cooled in an ice bath and treated with concentrated hydrochloric acid (200 ml). After 20 minutes the precipitate was collected by filtration, sucked briefly on the filter, slurried with methanol ( 500 ml) and again filtered. The product was dried in vacuo to give 302.3 g (98%) of the title compound as a light beige solid, mp 235°-237°.

Provenance & Evidence