The double reductive amination of L-arabino-hexos-5-ulose with benzhydrylamine and NaBH3CN takes place in a diastereospecific manner giving in moderate chemical yield (36 %) the galactosidase inhibitor 1-deoxy-D-galactostatin. The aminocyclization of 2,6-di-O-benzyl-L-arabino-hexos-5-ulose is more complicated giving results dependent from the type of amine: with ammonia or methylamine a mixture of C-5 epimeric l-deoxyazapyranoses (D-galacto/L-ahro ratio -- 4:1) is obtained in 45-65 % combined yield, while with benzhydrylamine substantial amounts of an acyclic 1-deoxy- 1-benzydrylamino-hexitol (10 % yield) is isolated together with the expected 1-deoxyazasugars of the D-galacto and L-altro series.
Double reductive amination of L-arabino-hexos-5-ulose:a diastereoselective approach to 1-deoxy-D-galactostatin derivatives
CATELANI, GIORGIO;D'ANDREA, FELICIA;
1997
Abstract
The double reductive amination of L-arabino-hexos-5-ulose with benzhydrylamine and NaBH3CN takes place in a diastereospecific manner giving in moderate chemical yield (36 %) the galactosidase inhibitor 1-deoxy-D-galactostatin. The aminocyclization of 2,6-di-O-benzyl-L-arabino-hexos-5-ulose is more complicated giving results dependent from the type of amine: with ammonia or methylamine a mixture of C-5 epimeric l-deoxyazapyranoses (D-galacto/L-ahro ratio -- 4:1) is obtained in 45-65 % combined yield, while with benzhydrylamine substantial amounts of an acyclic 1-deoxy- 1-benzydrylamino-hexitol (10 % yield) is isolated together with the expected 1-deoxyazasugars of the D-galacto and L-altro series.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
