The chloroacetyl group in synthetic carbohydrate chemistry

Bertolini, Maurice J.; Glaudemans, Cornelis P.J.

doi:10.1016/s0008-6215(00)88010-6

Cited by 116 publications

(50 citation statements)

References 15 publications

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“…For this reason, selective benzoylation of allyl 4,6-O-benzylidene-a-dglucopyranoside (8) [20] was performed with benzoyl imidazole, which resulted in the formation of 9 in a good yield of 74 %. Subsequent chloroacetylation [21] (3 10, 96 %), deallylation by isomerisation of the double bond with Wilkinsons catalyst [22] and removal of the 1-propenyl group with N-iodosuccinimide and water [23] (3 11, 77 %), and trichloroacetimidation [24] afforded monosaccharide donor 12 (93 %). Monosaccharide acceptor 17, containing a 3-azidopropyl spacer, was prepared from 5 (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Streptococcus pneumoniae Type 3 Neoglycoproteins Varying in Oligosaccharide Chain Length, Loading and Carrier Protein

2001

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The preparation is described of a range of neoglycoproteins containing synthesised fragments of the capsular polysaccharide of Streptococcus pneumoniae type 3, that is b-d-GlcpA-. A blockwise approach was developed for the synthesis of the protected carbohydrate chains, in which the carboxylic groups were introduced prior to deprotection by selective oxidation of HO-6 in the presence of HO-4 by using TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy radical). After deprotection, the 3-aminopropyl spacer of the fragments was elongated with diethyl squarate (3,4-diethoxy-3-cyclobutene-1,2-dione) and the elongated oligosaccharides were conjugated to CRM 197 (cross-reacting material of diphtheria toxin), KLH (keyhole limpet hemocyanin) or TT (tetanus toxoid). The resulting neoglycoconjugates varied in oligosaccharide chain length, oligosaccharide loading and protein carrier. These welldefined conjugates are ideal probes for evaluating the influence of the different structural parameters in immunological tests.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Streptococcus pneumoniae Type 3 Neoglycoproteins Varying in Oligosaccharide Chain Length, Loading and Carrier Protein

2001

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“…Our extensive experience with introduction and cleavage of haloacetyl groups [20,21] prompted us to first explore the utility of the chloroacetyl group for that purpose. The chloroacetyl group can be introduced under mild basic conditions using chloroacetyl chloride and, preferably, tetramethylurea [22] (TMU) in dichloromethane, and several reagents [23][24][25] that leave other acyl groups intact are available for its removal. The influence of haloacetyl groups on the reactivity at the anomeric center of carbohydrates is not clear.…”

Section: Resultsmentioning

confidence: 99%

Formation of Ethyl 1‐Thiomannopyranosides from 2‐O‐Chloroacetylated and 2‐O‐Levulinoylated Synthons

Adamo

Kòváč

2006

Eur J Org Chem

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With the aim to prepare key glycosyl donors for the synthesis of fragments of the O‐specific polysaccharides of Vibrio cholerae O:1, 1‐O‐acetyl derivatives of perosamine bearing participating 2‐O‐chloroacetyl or 2‐O‐levulinoyl groups were treated with EtSH and BF3·Et2O. While poor stereoselectivity of the formation of ethyl 1‐thioglycosides (α:β = 3:2) was observed with 2‐O‐chloroacetylated intermediates, the same products can be obtained with good stereoselectivity (α:β = 7:1) from 2‐O‐levulinoylated intermediates. Selective regeneration of the carbonyl group from dithioketals in the presence of S,O‐acetals by treatment with AgNO3 and Ag2O in MeCN/H2O is also described. The conversion allows direct preparation of 1‐thioglycosides from carbohydrates protected with the levulinic ester group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…Chloroacetylation (90%) of allyl 3-O-acetyl-4,6-O-benzylidene-a-D Dmannopyranoside 13 (1), followed by debenzylidenation (89%) and selective 6-O-benzoylation (95%), gave the glycosyl acceptor 4. Condensation of 4 with 2,3,4-tri-O-benzoyl-D D-xylopyranosyl trichloroacetimidate 14 (5) afforded b-(1!4)-linked disaccharide 6 (80%), and subsequent dechloroacetylation 15 produced disaccharide acceptor 7 (85%). Coupling of 7 with 5 afforded the trisaccharide 8 (80%) and subsequent deacetylation 16 produced the trisaccharide acceptor 9 (85%).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of a heptasaccharide fragment of the O-deacetylated GXM of C. neoformans serotype C

Zhao¹,

Kong²

2005

Carbohydrate Research

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(5) furnished the b-(1!4)-linked disaccharide 6. Dechloroacetylation gave the disaccharide acceptor 7 and subsequent coupling with 5 produced the trisaccharide 8. Deacetylation of 8 gave the trisaccharide acceptor 9 and subsequent coupling with a disaccharide 10 produced the pentasaccharide 11. Reiteration of deallylation and trichloroacetimidate formation from 11 yielded the pentasaccharide donor 12. Coupling of a disaccharide acceptor 13 with 12 afforded the heptasaccharide 14. Subsequent deprotection gave the heptaoside 16, while selective 2-O-deacetylation of 14 gave the heptasaccharide acceptor 15. Condensation of 15 with glucopyranosyluronate imidate 17 did not yield the expected octaoside, instead, an orthoester product 18 was obtained. Rearrangement of 18 did not give the target octaoside; but produced 15. Meanwhile, there was no reaction between 15 and the glycosyl bromide donor 19.

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The chloroacetyl group in synthetic carbohydrate chemistry

Cited by 116 publications

References 15 publications

Synthesis of Streptococcus pneumoniae Type 3 Neoglycoproteins Varying in Oligosaccharide Chain Length, Loading and Carrier Protein

Synthesis of Streptococcus pneumoniae Type 3 Neoglycoproteins Varying in Oligosaccharide Chain Length, Loading and Carrier Protein

Formation of Ethyl 1‐Thiomannopyranosides from 2‐O‐Chloroacetylated and 2‐O‐Levulinoylated Synthons

Synthesis of a heptasaccharide fragment of the O-deacetylated GXM of C. neoformans serotype C

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