l-Glutamic acid has been converted into a separable mixture of d-amicetono- and l-rhodinono-γ-lactones by a sequence involving transformation into (S)-γ-carboxy-γ-butyrolactone (2), conversion of 2, conversion of 2 into the corresponding methyl ketone by the diazoketone route, and selective reduction with zinc borohydride or borane-methyl sulfide. Reduction of the two lactones with di-isobutylaluminium hydride gave the corresponding deoxy sugars. In spite of some improvements in the preparation of 2, the optical yield of this step was only ∼80%, but one crystallisation from chloroform raised the optical purity to 96%. The subsequent steps produced a loss in optical purity of only 4%.
SYNTHESIS OF D-AMICETOSE AND L-RHODINOSE FROM L-GLUTAMIC ACID
CATELANI, GIORGIO;
1983-01-01
Abstract
l-Glutamic acid has been converted into a separable mixture of d-amicetono- and l-rhodinono-γ-lactones by a sequence involving transformation into (S)-γ-carboxy-γ-butyrolactone (2), conversion of 2, conversion of 2 into the corresponding methyl ketone by the diazoketone route, and selective reduction with zinc borohydride or borane-methyl sulfide. Reduction of the two lactones with di-isobutylaluminium hydride gave the corresponding deoxy sugars. In spite of some improvements in the preparation of 2, the optical yield of this step was only ∼80%, but one crystallisation from chloroform raised the optical purity to 96%. The subsequent steps produced a loss in optical purity of only 4%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
