[CH2:1]([C:4]1[NH:5][C:6]([C:10]([CH3:12])=O)=[C:7]([CH3:9])[N:8]=1)[CH2:2][CH3:3].[C:13](OCC)(=[O:16])[NH:14][NH2:15]>C(O)(=O)C.C(O)CCC>[CH3:12][C:10]1[C:6]2[N:5]([C:4]([CH2:1][CH2:2][CH3:3])=[N:8][C:7]=2[CH3:9])[C:13](=[O:16])[NH:14][N:15]=1A mixture of 59.7 g. of methyl 2-n-propyl-4-methyl-5-imidazolyl ketone, 41.14 g. of ethyl carbazate, 200 ml. of n-butanol and 4 drops of glacial acetic acid is warmed until solution is complete and then heated under reflux for 5 hours. The solution is concentrated in vacuo to an oily residue, 250 ml. of diphenyl ether are added and the resulting solution is heated with stirring in an oil bath for 30 minutes after the start of gas evolution. The temperature is maintained as closely as possible to the point at which gas evolution starts (150°-250° C.). The reaction is removed from the oil bath, cooled to 50° C. and diluted with 1-2 volumes hexane. The product is collected, washed with petroleum ether and then dissolved in 200 ml. of chloroform. This solution is filtered through 250 ml. of Magnesol® followed by an 800 ml chloroform wash. The filtrate is concentrated in vacuo and the residue is recrystallized from 250 ml. of ethyl acetate, giving 48.2 g. of the desired product as off-white crystals, m.p. 154°-155° C.
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