D-Talopyranose

Draw structures for the products you would expect to obtain from reaction of /3-D-talopyranose with each of the following reagents ... 

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... 

CnH16C>7 Methyl 3,4-di-0-acetyl-2,6-anhydro-/ -D-talopyranose MATALP 38 442... 

An anhydro sugar which will probably find extensive synthetic use has been described by Hann and Hudson.85 This is the tricyclic compound, 3,4 1,6-dianhydro-jS-D-talopyranose (LXXIV) which is prepared by the saponification of the 4-tosyl derivative of mannosan (LXXIII). 

Ferner sind noch 2,3-0-Isopropyliden- und 3,4-0-Isopropyliden-l,6-anhydro-D-talopyranose bekannt 100,106,111)... 

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]. 

The deamination of methyl 3-amino-3-deoxy-/3-D-altropyranoside was studied in 1934, but the products were not fully characterized.14411 The syrupy product was converted into a methylated derivative that had an elemental analysis corresponding to that calculated for a methyl tetramethylhexoside. The conditions used for methyl-ation would have opened an epoxide ring. Methyl 2,3-anhydro-4,6-0-benzylidene-a-D-mannopyranoside precipitated quantitatively from solution when the corresponding 3-amino-3-deoxyaltroside derivative was deaminated in aqueous medium.145 Epoxide formation was likewise reported to be quantitative in the deamination of the analogous 2-amino-2-deoxyaltroside.83 145 On deamination, 4-amino-l,6-anhydro-4-deoxy-/3-D-mannopyranose also gave an epoxide, namely, 1,6 2,3-dianhydro-/3-D-talopyranose, in unspecified yield.146... 

In the case of 1,6 2,3- (136) and l,6 3,4-dianhydro-/I-D-talopyranoses, the diaxial opening of the oxirane ring prevails, but a trend to diequatorial opening496 498 is apparent with l,6 2,3-dianhydro-4-deoxy- and 1,6 3,4-dianhydro-2-deoxy-/l-D-/yxo-hexopyranoses.169,432,493 Using 1,6 2,3- and l,6 3,4-dianhydrohexopyranoses as starting compounds allowed the preparation of a complete series of 12 isomeric 1,6-anhydro-monodeoxy-/Fn-hexopyranoses and 6 corresponding 1,6-anhydro-dideoxyhexoses,499 mainly by catalytic or complex hydride reductions.462,500... 

Z. GanandF. Kong, Synthesis of 2,6-dioxabicyclo[3.3.1]heptanes l,3-anhydro-2,4,6-tri-0-benzyl-jS-D-talopyranose, Carbohydr. Lett., 1 (1994) 27-30. 

A. K. Chatterjee, D. Horton, J. S. Jewell, and K. D. Philips, Synthesis of 1,6-anhydro derivatives of 2-amino-2-deoxy-jS-D-talopyranose and 4-amino-4-dcoxy-/i-n-talopyranose, Carbohydr. Res., 7 (1968) 173-179. 

Talose is the C4 epimer of mannose. Draw the chair conformation of D-talopyranose. 

Anhydro-0-D-talopyranose (91) Ether Toluene NMI 120 Benzyl bromide O 0 0 68... 

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... 

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