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Eleven new su~ar der ivatives and numerous optical rotation and hydrolysis measurements are r eported. A comparison of the alpha and beta methyl glucosides, mannosides, galactosides, and gulosides shows that the configurations of all of the asymmetric carbons in the pyranose ring affect the rate of hydrolysis, and that there is no fixed relationship between the configuration of the glycosidic carbon and the relative rates for the hydrolysis of the alpha and beta modifications. The configur ation of carbon 3 appears to influence markedly the relative rates for the hydrolysis of the alpha and beta modifications. Aldo-pyranosides having trans configurations for carbons 1 and 3 are hydrolyzed more slowly than the corr esponding modifications having cis configurations for carbons 1 and 3. This unexpect edly large influence of carbon 3, and the close resemblance of each pent ose t o the corresponding h exose which has t he trans configuration for carbons 3 and 5 are discussed in r elation to t he spacial arrangement of the whole molecule. The similarity of the methyl gulosides and a-glucoheptosides on the one hand, and t he methyl Iyxosides, mannosides, and a-galaheptosides on the other hand, furnishes a substantial basis for the allocation of Iyxose to the mannose series. CONTENTS Page I. Structural and configurational relationships for the pentoses, hexoses, and heptoses __________
Isbell et al. (Thu,) studied this question.