Starting from DL-a-aminobutyric acid and DL-v a line the corresponding aminoalkylglyoxals VIIa and VIIb were prepared by Krohnke\u27s method , through the reaction stages II-VII. Further, a description is given of the pireparation of DL-1-acetoxy-3-phthalim idorpent an- 2-one, and of the conversion of the glyoxal VIIa into the 1, 1-diethylacetal VIIIa, the hydroxyacetal IXa, and the a-glycol Xa, which are useful intermed iates for the synthesis of compounds of the type I. The aldehyde group of these glyoxals readily reacts with N,N-diphe n yl-1,2-dia minoethane, affording condensation products XI. Quinoxaline and bisethylenemerc aptal derivatives of the glyoxals VII were also prepared. Improved pireparations are described for DL- a - amino butyric acid and the corresponding phthalimido derivative
