Acetobromo-a-D-glucose

Recently, a total synthesis of salmochelin SX (70) has been reported which used cross-coupling of acetobromo-a-D-glucose 96 with arylzinc derivative 97 to furnish 98, followed by full deacylation and perbenzylation to give 99. Subsequent saponification of the methyl/benzyl ester, formation of the acid chloride, and addition of a protected L-serine unit yielded 100. Final deprotection formed the glucosyl-DHB-serine 70 in 28% overall yield (Fig. 17) [121]. This strategy involved the stepwise addition of the aryl moiety and serine (76a) to the sugar portion, which is in the opposite order to the biosynthetic rationale. 

The preparation of acetobromo-a>D-glucose from the penta-0-acetyl-/ -D-glucose obtained from D-glucose by means of acetic anhydride and sodium acetate331,1016 is well known, but the method described in detail in Organic Syntheses1017 is simpler. 

Acetobromo-a-D-glucose D-Glucose monohydrate (0.33 mole) is first acetylated with acetic anhydride (280 ml) containing 3 drops of concentrated H2S04, then 200 ml of an acetic acid-anhydride mixture is distilled off, fresh acetic anhydride (60 ml) is added, and HBr (140-160 g) is led in with cooling in ice. The mixture is kept overnight, then HBr, acetic acid, and acetic anhydride are distilled off from a bath at not more than 60° under diminished pressure and finally in an oil-pump vacuum (less than 5 mm) and the residue is recrystallized from diisopropyl ether. 

Thus bromine that has been distilled over H2S04 converts ethyl 2,3,4,6-tetra-0-acetyl-/ -D-thioglucoside in dry ether at 20° into acetobromo-a-D-glucose, and ethyl 2,3,4,6-tetra-O-acetyl-a-D-thioglucoside into the otherwise inaccessible acetobromo-/ -D-glucose.1288... 

A novel in vitro glucuronidation of a phenolic substrate was carried out with rat liver microsomes [22]. The method is simple, the reagent is optically pure, only the (4- )-glucuronic acid (13) is present, and the individual enantiomers are readily recovered by a simple enzymatic hydrolysis. Glucosidation with acetobromo-a-D-glucose (14) has also been used to separate the enantiomers of menthol [23]. 

COCH3 - Obtained by reaction of acetobromo-a-D-glucose with resacetophenone,... 

Preparation by glycosation of 2,6-dihydroxyacetophenone with acetobromo-a-D-glucose,... 

Obtained by reaction of acetobromo-a-D-glucose with phloracetophenone in the presence of 2.25 N aqueous sodium hydroxide in acetone at 0° (9-12%) [3715]. 

Tetra-O-acetyI-a-glucosyl bromide (Acetobromo-rf-D - glucose)... 

Glucose derivatives. a-D-Glucose i-phosphate can be prepared by the action of potato phosphorylase on starch or synthesized from acetobromo glucose and trisilver phosphate or silver diphenyl phosphate . 

Isbell and Frush10 have reported an extensive study of the reaction of a-acetobromo-D-glucose with methanol, silver carbonate, and the water liberated in the reaction as by-product,... 

In contrast to the result obtained with a-acetobromo-D-glucose, Isbell and Frush10 found the reaction of a-aeetobromo-D-mannose under parallel... 

Hurd and Holysz34 obtained a 20% yield of tetra-O-acetyl-jS-D-gluco-pyranosylbenzene (CVIII) on reacting a-acetobromo-D-glucose (CVII) with one mole of diphenylcadmium in boiling toluene and, under the same conditions, a 29% yield of tetra-O-acetyl-a-D-mannopyranosylbenzene (CX) was obtained from a-acetobromo-D-mannose (CIX). The authors... 

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