organic compounds
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A second crystalline diacetonide, the title compound, C13H20O7, has been isolated from the sequential treatment of D-tagatose with aqueous sodium cyanide, followed by acetone in the presence of acid. Structural ambiguities with regard to the size of both the lactone and ketal rings are resolved by the X-ray crystallographic analysis.
organic compounds
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The crystal structure of the title compound, C20H28O6, allows a firm assignment of the stereochemistry at C-4 of formation of the tetrahydrofuran (THF) ring.
organic compounds
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The crystal structure of diacetone tagatose, C12H20O6, establishes the stereochemistry of the anomeric spiroacetal as 1,2:3,4-di-O-isopropylidene-α-D-tagatofuranose. Molecules are linked by O—HO hydrogen bonds [OO = 2.862 (2) Å] to form chains running parallel to the b axis.
organic compounds
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The crystal structure of the title diacetone psicose, C12H20O6, establishes the stereochemistry of the anomeric spiroacetal 1,2:3,4-di-O-isopropylidene-β-D-psicofuranose. The structure consists of columns of molecules linked by hydrogen bonds into chains [OO 2.962 (2) Å] lying parallel to the a axis.
organic compounds
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The crystal structure of the title benzyl ether, C20H26O7, establishes the stereochemistry of the major diacetonide product from the Kiliani reaction of D-psicose. There are two independent molecules in the cell related by a pseudo-twofold screw axis. There are no suitable donors for strong hydrogen bonds: the molecules are simply in van der Waals contact.