To a stirred suspension of 60% sodium hydride (0.52 g) in dimethylformamide (20 ml) is added under ice-coolinga solution of ethanethiol (0.81 g) in dimethylformamide (5 ml). After the mixture is stirred at 25° C. for 0.5 hour, 4-amino-N-[(4-benzyl-2-morpholinyl)methyl]-5-chloro-2-methoxybenzamide (3.4 g) is added, and the mixture is stirred at 100° C. for 1 hour. After cooling, the reaction mixture is evaporated under reduced pressure. The residue is diluted with water, washed with chloroform, and neutralized with 10% hydrochloric acid. The precipiate is collected, washed with water, and recrystallized from isopropyl alcohol to give the monohydrate of the title compound (2.3 g), mp 153°-155° C.
