title: Methyl (2'S,3'S)-3,4-O-(2',3'-dimethoxy-butane-2',3'-di-yl)-α-l-rhamnopyran-oside: a glycosyl acceptor.
abstract: The title compound, C(13)H(24)O(7), is the product of the ketalization of methyl l-(+)-rhamnopyran-oside with 2,3-butane-dione. It crystallizes with two mol-ecules in the asymmetric unit, which are connected by O-H⋯O hydrogen bonds. The C-3,4 diequatorial hydroxy groups of the methyl l-(+)-rhamnopyran-oside were protected, leaving the C-2 hydroxy group free. The l-(+)-rhamnopyran-oside and 2',3'-dimethoxy-butane-2',3'-diyl rings adopt chair conformations and all meth-oxy groups are in axial positions. The absolute configuration was assumed from the synthesis.
authors.affiliation: Department of Chemistry, Chung-Yuan Christian University, Chung-Li 320, Taiwan.
authors.forename: Yow-Fu
authors.initials: YF
authors.lastname: Tsai
authors.forename: Jen-Ta
authors.initials: JT
authors.lastname: Yang
authors.forename: Jhy-Der
authors.initials: JD
authors.lastname: Chen
authors.forename: Chia-Her
authors.initials: CH
authors.lastname: Lin