Procedures for the direct replacement of primary hydroxyl groups in carbohydrates by halogen

Hanessian, Stephen; Ponpipom, Mitree M.; Lavallée, Pierre

doi:10.1016/s0008-6215(00)82258-2

Cited by 189 publications

(51 citation statements)

References 37 publications

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“…A solution of NaOH (40 g)-mercaptoethanol (11.34 ml)-water (37.5 ml) was stirred at 0°C for 0.5 h and then added to a round-bottom flask containing methyl 5-deoxy-5-chloro-2,3-O-isopropylideneribofuranoside (15 g), which was prepared from methyl 2,3-O-isopropylideneribofuranoside as described by Hanessian et al (10). The reaction mixture was heated with stirring at 80°C for 3 days, cooled, and extracted with ether (three times with 100 ml each time).…”

Section: Methodsmentioning

confidence: 99%

5'-Alkyl-substituted analogs of 5'-methylthioadenosine as trypanocides

Bacchi

Sufrin

Nathan

et al. 1991

Antimicrob Agents Chemother

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5'-Deoxy-5'-(methylthio)adenosine (MTA) is a by-product of polyamine metabolism and is phosphoryolytically cleaved to adenine and 5-deoxy-5-(methylthio)ribose-1-phosphate (MTR-1-P) by MTA phosphorylase. In eukaryotes, adenine is subsequently salvaged and converted to nucleotides, while MTR-1-P is converted to methionine. We examined 5'-deoxy-5'-substituted analogs of MTA for trypanocidal activity in vitro and in vivo. 5'-Deoxy-5'-(hydroxyethyl)thioadenosine (HETA) and its 5'-bromo,5'-chloro and 5'-fluoro derivatives were cleaved by extracts of the African trypanosome Trypanosoma brucei brucei (Km for MTA, 11.5 ,uM; Km for HETA, 13.2 ,uM) in a phosphate-dependent reaction. HETA and the three halo analogs were 50% inhibitory to growth at 0.5 to 5.0 ,uM in vitro. Inhibition of growth was reversible by exogenous methionine and 2-keto-4-methylthiobutyric acid, an intermediate in methionine synthesis from MTR-1-P. HETA was selected for further study in vivo. When administered by miniosmotic pump (25 to 150 mg/kg/day for 7 days) to mice infected with T. brucei brucei, HETA effected 70 to 90% cure rates. Results of this study indicate that these analogs of MTA are converted to trypanocidal MTR-1-P analogs and that this approach deserves further consideration in the development of novel chemotherapy of trypanosomiasis.5'-Deoxy-5'-methylthioadenosine (MTA) is the nucleoside product of aminopropyl group transfer from decarboxylated S-adenosylmethionine in the formation of the polyamines spermidine and spermine (16). In mammalian cells, MTA is rapidly cleaved by MTA phosphorylase to adenine and 5'-deoxy-5'-(methylthio)ribose-1-phosphate (MTR-1-P, Fig.

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Section: Methodsmentioning

confidence: 99%

5'-Alkyl-substituted analogs of 5'-methylthioadenosine as trypanocides

Bacchi

Sufrin

Nathan

et al. 1991

Antimicrob Agents Chemother

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“…Nevertheless, the good conversion implies that clean regeneration of dibenzophosphole takes place, in contrast to the reaction with tetrabromomethane. The majority of alternative reagents (i.e., bromine, [25] N-bromosuccinimide, [26] N-bromoacetamide, 2,4,4,6-tetrabromocyclohexa-2,5-dienone) [27] reacted quickly with diphenylsilane ( Figure 4). However, diethyl bromomalonate (DEBM, 17) reacted only slowly with diphenylsilane and was therefore selected for further investigations.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

In Situ Phosphine Oxide Reduction: A Catalytic Appel Reaction

Kalkeren

Leenders

Hommersom

et al. 2011

Chemistry A European J

162

121

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Several important reactions in organic chemistry thrive on stoichiometric formation of phosphine oxides from phosphines. To avoid the resulting burden of waste and purification, cyclic phosphine oxides were evaluated for new catalytic reactions based on in situ regeneration. First, the ease of silane-mediated reduction of a range of cyclic phosphine oxides was explored. In addition, the compatibility of silanes with electrophilic halogen donors was determined for application in a catalytic Appel reaction based on in situ reduction of dibenzophosphole oxide. Under optimized conditions, alcohols were effectively converted to bromides or chlorides, thereby showing the relevance of new catalyst development and paving the way for broader application of organophosphorus catalysis by in situ reduction protocols.

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“…-C-glycosides can be explained by a more effecThe availability of 2,3:5,6-di-O-iso~ro~~1i-tive separatioll of charges in the transition state dene-D-mannofuranosyl halides (26,27) P~O~P -leading to a more favored (less hindered) a ted a study of their reactions with sodio diethyl attack. malOnate.…”

Section: I3mentioning

confidence: 99%

“…The residue was extracted with chloroform, residual salts were removed by filtration, and the filtrate was evaporated to a syrup that was separated from traces of impurities by preparative t. ~-~-t~l~l t l~f u r a t l~~y / ma lot rate^ (23, 24) Finely cut sodiilm (1.67 g) was dissolved in 100 ml of diethyl malonate at 50-60". The cooled solution was added to a solution of 2,3 :5,6-di-0-isopropylidene-WDmannofuranosyl bromide 22 (6.7 g) (26,27) in the minimum volume of diethyl malonate. The solution was stirred at room temperature overnight, diluted with a large excess of ether, and processed in the ilsual manner.…”

Section: Periodate Osirla/iot~ Atlrl At~otneric Cot~fig~mntiot~almentioning

confidence: 99%

Carbanions in Carbohydrate Chemistry: Synthesis of C-Glycosyl Malonates

Hanessian¹,

Pernet²

1974

Can. J. Chem.

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The condensation of 2,3,4,6-tetra-0-acetyl-a-D-glucopyranosyl bromide with sodio diethyl malonate led to crystalline diethyl 2-(2,3,4,6-tetra-0-acetyl-(3-o-glucopyranosyl) malonate. The corresponding dibenzyl ester proved to be a versatile intermediate for the preparation of crystalline e-D-glucopyranosyl malonic acid and P-D-glucopyranosyl acetic acid derivatives. The anomeric configuration in these C-glycosides was determined by a chemical correlation. With 2,3,4,6-tetra-0-acetyl-0-D-glucopyranosyl chloride and sodio diethyl malonate, the major product was a 1,2-0-ketal derivative resulting from an attack of the carbanion on the 1,2-acetoxonium ion. The condensation of 2,3,4,6-tetra-0-benzyl-a-o-glucopyranosyl bromide with sodio diethyl malonate was conducted with, and without added bromide ion and the mechanistic implications of the results are discpssed. C-Glycosides were also prepared in the D-mannofuranose series and their transformation into the D-lyxofuranose series (anomeric mixture) is described. The utility of n.m.r. shift reagents, and a n apparent differential complexation by Eu(DPM), and Eu ( Can. J. Chem., 52, 1266 (1974)

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Procedures for the direct replacement of primary hydroxyl groups in carbohydrates by halogen

Cited by 189 publications

References 37 publications

5'-Alkyl-substituted analogs of 5'-methylthioadenosine as trypanocides

5'-Alkyl-substituted analogs of 5'-methylthioadenosine as trypanocides

In Situ Phosphine Oxide Reduction: A Catalytic Appel Reaction

Carbanions in Carbohydrate Chemistry: Synthesis of C-Glycosyl Malonates

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