Hexodialdo-1,5-pyranoside

Me glycoside, 2,3-dibenzyl Methyl 2,3-di-0-benzyl-4-deoxy-a-D-xy o-hexodialdo-pyranoside [116013-33-3]... 

Theander demonstrated that methyl hexodialdo-l,5-pyranosides, which form a hemiacetal with the 3-hydroxyl group (as in 15) are... 

Other methods have been reported which, however, lacked generality. One of these described the approach to L-g/ycera-D-manno-heptopyranosides by stereoselective chain extension of suitably protected hexodialdo-l,5-pyranosides with silylmethylmagnesium chlorides [31]. Another method, quite reminiscent of the Masamune-Sharpless approach [7g], reported the synthesis of four stereoisomeric tetrose derivatives by homologation of... 

Stereocontrolled ethynylation of methyl 2,3,4-tri-O-benzyl-a-D-g/Hco-hexodialdo-l,5-pyranoside (52) with a Grignard reagent formed from trimethylsilylacetylene, followed by a multistep procedure afforded the aminouronic acid 53, the a-amino acid on which miharamycin A is based.168 Uronic acid derivatives have also been produced by the Wittig reaction on the aldehydic side chain of dialdofuranose compounds.169... 

Galactose oxidase (EC 1.1.3.9), which catalyzes the oxidation of D-galac-tose (and derivatives) to D-gu/ucm-hexodialdose (and derivatives), is useful for analytical determinations,388 but is not an efficient method for large-scale preparation of methyl D-ga/ucm-hexodialdo-l,5-pyranosides. The fi anomer of the latter was characterized as a dimeric hexaacetate.389... 

The unsaturated hexodialdopyranosides formed are very readily transformed by either alkaline or acid treatment into brown, polymerized products. Acid treatment of 186, the / -elimination product of methyl a-D-g/ co-hexodialdo-l,5-pyranoside, produced the reactive intermediates 187 and 188.391 The 2,3-diacetate of 186 was obtained by Perlin et al. by an oxidation / -elimination reaction.392... 

Rate Constants and Activation Energies for the Hydrolysis of Methyl g-D Glucopyranoside and Methyl J-D-gluco-Hexodialdo-l, 5-pyranoside and their 4-Methyl Ethers ... 

Methyl a-D-ga/flc o-hexodialdo-l,5-pyranoside, H-84 Methyl p-D-gfl/ac o-hexodialdo-l,5-pyranoside, H-84 Methyl a-D-g/wco-hexodialdopyranoside, H-85 Methyl p-D-g/wco-hexodialdopyranoside, H-85 Methyl a-L-g/wco-hexodialdopyranoside, H-85 Methyl p-L-g/wco-hexodialdopyranoside, H-85 Methyl a-D-xy/o-hexopyranosid-4-ulose 0-methyloxime, H-104 Methyl y.- D-arabino -hexopyranosid-2-ulose, H-94 Methyl p-D-xy/o-hexopyranosid-4-ulose, H-104 Methyl a-D-rj o-hexopyranos-3-uloside, H-101 Methyl D-flm6 w -hex-2-ulosonate, H-111 Methyl 3-0-(4-hydroxycinnamoyl)glycerate, D-709 Methyl 4-C-(hydroxyinethyl)-2,3-0-isopropylidene-p-D-eryf/iro-pentofuranoside, H-172... 

Theander s group has studied the reactions of several dialdose derivatives. Methyl a-D- / co-hexodialdo-l,5-pyranoside underwent -elimination and then conversion into the dienone (270) and the furan dicarboxaldehyde (271) on treatment with aqueous alkali (Scheme 103). The degradation of methyl a-o-... 

Degradation of methyl 2,3-di-0-ethyl-4-0-propyl-a-D- / co-hexodialdo-l,5-pyranoside (304) with sodium ethoxide yielded the methyl -L-threo-hQx-4-enopyranoside derivative (305), which lost most of the remaining alkoxy-groups on heating with aqueous acetic acid. The isomeric hexopyranosid-4-ulose (306) also rapidly lost a substantial proportion of its alkoxy-groups on treatment either with sodium butoxide or with sodium butoxide followed by aqueous acetic acid. Both (304) and (306) also released methanol, ethanol, and propanol... 

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