Vol. G8ing point determination with authentic 2,4-methylenexylitol caused no depression of this value. The yield was 2.8 g. (889$). The series of reactions constitutes a definitive proof that monomethylene-gluco-gulo-heptitol is 3,5-methylene-gluco-Qulo-heptitol.Although the expected dialdehydo oxidation product from 3,5-methylene-gluco-guZo-heptitol could not be crystallized, i t was isolated in a separate experiment in the Form of its di( phenylhydrazone). The latter compoui~d crystallized from 30 parts of alcohol as small, light yellou plates which melted with decomposition a t 188-190'.
SummaryProof is presented that the monobenzylidene-gluco-gulo-heptitol (m. p. 21s') which Emil Fischer discovered is the 3,5-benzylidene acetal. The condensation of gluco-gulo-heptitol with formaldehyde also gives a high yield of a monoacetal which proves to be 3,5-monomethylene-glucocub-heptitol. These 3,5-monoacetals are those to he expected from generalizations relating the configuration of polyhydric alcohols and the structure of their derived benzylidene and methylene acetals.Crystalline 2,4-benzylidene-xylitol and a number of its derivatives have been described. RETHESDA, R~ARYLAND RECEIVED MAY 9, 1946 'CONTRIBUTIOS FROM THE STERLING-\VIS1 IIROP RESEaRCH [NSTIrUTE ]
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.