[N:1]1([CH:6]([C:10]2[CH:11]=[C:12]([NH2:17])[C:13]([NH2:16])=[CH:14][CH:15]=2)[CH:7]([CH3:9])[CH3:8])[CH:5]=[CH:4][N:3]=[CH:2]1.C(O)(=O)C.O=[C:23]([CH2:27][CH2:28][CH3:29])[C:24](O)=[O:25].[OH-].[Na+]>O>[N:1]1([CH:6]([C:10]2[CH:11]=[C:12]3[C:13](=[CH:14][CH:15]=2)[NH:16][C:24](=[O:25])[C:23]([CH2:27][CH2:28][CH3:29])=[N:17]3)[CH:7]([CH3:8])[CH3:9])[CH:5]=[CH:4][N:3]=[CH:2]1To a stirred and cooled (0° C.) mixture of 9 parts of 4-[1-(1H-imidazol-1-yl)-2-methylpropyl]-1,2-benzenediamine in 80 parts of acetic acid and 20 parts of water were added 5 parts of 2-oxopentanoic acid. The reaction mixture was stirred for 12 hours at room temperature. The whole was poured into ice water and neutralized with a sodium hydroxide solution 3N. The product was extracted three times with 130 parts of dichloromethane. The combined extracts were dried, filtered and evaporated. For obtaining 6-[1-(1H-imidazol-1yl)-2-methylpropyl]-3-propyl-2(1H)-quinoxalinone, the residue was purified by column chromatography (HPLC) over silica gel using a mixture of dichloromethane and methanol (98:2 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 2-butanone and 1,1'-oxybisethane. The precipitated product was filtered off and stirred in cold 4-methyl-2-pentanone. After filtration, the product was recrystallized from a mixture of methanol and 2-propanone, yielding 1.6 parts (13.2%) of the above product; mp. 259.7° C. (comp. 100).
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