P-D-Talopyranose

Methyl p-D-talopyranose-2-C,4-C-diylphosphinite or 2-C,4-C-fmethoxyphosphanediyl)-p-D-glucopyranose or (2fl,4S)-2-C,4-C-(methoxyphosphanediyl)-P-D-/hreo-hexopyranose... 

Die Reduktion mit NaBH4 gibt im Falle der Verbindungen a, b imd c die entsprechenden Hydroxy-Derivate mit aquatorialer Konfiguxation (also Derivate der D-allo-, D-gulo- imd o-altro-Reihe), nur aus d" entsteht die 2,4-Di-0-p-toluolsulfonyl-l,6-anhydro-p-D-talopyranose mit axialer HydroxyIgruppe am C-3 32),... 

Femer wurde 1,6-2,3-Dianhydro-p-D-talopyranose durch alkalische Hydrolyse des Bariumsalzes des l,6-Anhydro-p-D-galactopyranose-2-sulfats gewonnen... 

Es wurde gefunden, dafi, wenn im Molekul eine axiale Hydroxyl-gruppe an C-3 vorhanden ist, nur diese oxydiert wird. So bildet sich bei der katalytischen Oxydation von l,6-Anhydro- 3-D-glucopyranose (750), 1,6-Anhydro-p-D-galaktopyranose (752), 1,6-Anhydro-p-D-mannopyra-nose (756) und 1,6-Anhydro-p-D-talopyranose (760) in guten Ausbeuten... 

Formation of l,2 5,6-di-0-isopropylidene-a-D-n7i( -hexo-furanos-3-ulose (Fig. 2.13, 2.4.2.1 Table 2.3) was one of the first carbohydrate oxidations effected by stoich. RuOyCCl [310, 311]. The reagent was also used for oxidation of 1,6-anhydro-3,4-0-isopropylidene-P-D-galactopyranose to the -P-D-/yxo-hexopyranos-2--ulose, part of a route leading to 1,6-anhydro-P-D-talopyranose (Fig. 2.15) [321]. 

Hughes NA (1968) Further observations on derivatives of 1,6-anhydro-P-D-talopyranose an example of acetal migration accompanying hydrolysis. Carbohydr Res 7 474-479... 

Cleavage Reactions of l,6-Anhydro-4-0-benzyl-2,3-(A-tosylepimino)-2,3-dideoxy-P-D-talopyranose... 

Dibenzyl, 6-Ac 6-O-Acetyl-l,2-anhy-dro-3,4-di-0-benzyl-P-D-talopyranose C22H24O6 384.428 Md +14.3 (c, 2.5 in CHCI3). 

Oxirans. - The synthesis of l,2-anhydro-3,4-di-0-benzyl-6-deoxy-a-D-glucopyranose and its conformational analysis have been reported. A range of epoxides have been prepared by base treatment of bromohydrins, which were made by reaction of hydrogen bromide with aldonolactones. A one-pot conversion of vicinal diols into epoxides employs halohydrin ester intermediates generated from cyclic orthoacetates and either acetyl bromide or trimethylsilyl chloride. Levoglucosenone has been transformed into l,6 3,4-dianhydro-p-D-talopyranose by way of a trn/w-iodo-acetoxylation of the alkene moiety... 

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