6-[Bis(ethoxycarbonyl)methyl]-6-deoxy-1,2;3,4-di-O-isopropylidene-d-galactopyranose
نویسندگان
چکیده
The title compound, C(19)H(30)O(9), was prepared by substitution at the C6 position in 1,2;3,4-di-O-isopropyl-idene-6-O-trifluoro-methane-sulfonyl-d-galactose using sodium eth-oxy-malonate in dimethyl-formamide. The conformation is skew-boat (0)S(2), slightly distorted towards boat B(2,5). The inflexible pyran-ose structure makes the title compound a suitable inter-mediate for further synthetic work by keeping stereogenic carbon atoms safe from inversion. Several short intra-molecular C-H⋯ O contacts may stabilize the conformation of the mol-ecule. Inter-molecular C-H⋯O inter-actions also occur.
منابع مشابه
3-Deoxy-1,2-di-O-isopropylidene-5-O-tosyl-d-threo-pentofuranose
In the crystal structure of the title compound, C(15)H(20)O(6)S, the two independent mol-ecules crystalllize in a chiral setting with two different conformations, twisted (4)T(3) and envelope (4)E, for the furan-ose rings. Weak C-H⋯O contacts strengthen the crystal structure.
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The title compound, C8H12O6, was synthesized by de-acetyl-ation of 6-acetyl-1,2,3,4-di-O-methyl-ene-α-d-galactose with sodium methoxide. The central part of the mol-ecule consists of a six-membered C5O pyran-ose ring with a twist-boat conformation. Both fused dioxolane rings adopt an envelope conformation with C and O atoms as the flap. In the crystal, O-H⋯O and C-H⋯O hydrogen bonds are present...
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The mol-ecule of the title compound, C(13)H(21)NO(8), consists of two methyl-enedi-oxy rings and one tetra-hydro-furan ring. In the crystal, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into helical chains running along the 6(1) screw axis. Weak inter-molecular C-H⋯O hydrogen bonds help to stabilize the crystal packing. Voids of 245 Å(3) per unit cell occur.
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