Methylglyoxal → HCID 178441328, Verbindung
Reaktionsgleichung
O=[C:2]([CH2:5][CH2:6][CH2:7][CH3:8])[CH:3]=O.O=C(C)C=O.CC1[N:16]=[C:17]([OH:24])[C:18]([C:21]([NH2:23])=[O:22])=[N:19]C=1.NC(C(N)=O)C(N)=O>>[CH2:5]([C:2]1[N:16]=[C:17]([OH:24])[C:18]([C:21]([NH2:23])=[O:22])=[N:19][CH:3]=1)[CH2:6][CH2:7][CH3:8]Komponenten
5
Versuchsvorschrift
2-Oxohexanal (F. Ballistreri, et al., J. Organic Chem., 53, 830 (1988) is reacted (according to the method described by F. L. Muehlmann and A. R. Day in J. American Chem. Soc., 78, 242-4(1956) substituting 2-oxohexanal for the 2-oxopropanal used in the synthesis of 5-methyl-3-hydroxypyrazine-2-carboxamide) with aminomalonamide to give 5-n-butyl-3-hydroxypyrazine-2-carboxamide. The amide is hydrolyzed with sodium hydroxide in water at 95° C. to give 5-n-butyl-3-hydroxypyrazine-2-carboxylic acid. The acid is converted to the corresponding ester with methanol and hydrochloric acid and the ester is chlorinated with phosphorous oxychloride (according to the method described by G. Dick and H. Wood in J. Chem. Soc., 1955, 1379-82) to give the title compound.