Although the acid catalyzed alcohol interchange of simple acetals has been examined in some de- tail,' there are few reports in the literature con- cerning the behavior of substituted hydroxyacetals in acid medium. In this connection Montgomery, Hann and Hudson2 reported the preparation of a mixture of methyl-&arabinosides (11) by the ac- tion of methariolic hydrogen chloride upon d- arabinose dimethyl acetal (I). 0CH3 ocH3 I I I I I ... HCI HC- OH HC-013 I H2C- 013 I ...