Ethyl Acetate → 5-chloro-2-methyl-4-(2-methyl-5-phenylbenzyl)-2,4-dihydro-3H-1,2,4-triazol-3-one

Participants

Reaction Steps

To a solution of 9.24 g (31.1 mmol) of triphosgene in 50 ml of methylene chloride was added dropwise a solution of 4.41 g (15.6 mmol) of 1,1-dimethyl-4-(2-methyl-5-phenylbenzyl)semicarbazide (produced in the following Reference Production Example 15) in 35 ml of methylene chloride with ice-cooling. The mixture was removed from an ice bath, allowed to warm to room temperature, and heated under reflux for 6 hours. After allowing to cool to room temperature, the reaction mixture was poured into 300 ml of an about 5% aqueous solution of sodium bicarbonate, and the mixture was stirred for 1 hour. The organic layer was washed with water, dried and concentrated. The residue was subjected to silica gel column chromatography (developed with n-hexane:ethyl acetate=2:1and then 1:1) to obtain 2.01 g (6.4 mmol) of 5-chloro-2-methyl-4-(2-methyl-5-phenylbenzyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (the compound 7 of the present invention) having a melting point of 115.7° C.

Provenance & Evidence