Condensation ofD-talose with nitromethane in alkaline methanol gave the corresponding epimeric 1-deoxy-1-nitroheptitols which were converted intoD-glycero-L-altro-heptose andD-glycero-L-allo-heptose (1.5:1) in 44% yield. Reduction ofD-glycero-L-altro-heptose with sodium borohydride gave the hitherto unknownmeso-glycero-altro-heptitol. The gas–liquid chromatography retention times of the 10 geometrically isomeric heptitol heptaacetates were determined. These data provide the necessary information for the key step in a procedure for the rapid identification of an unknown heptose.