Reactions of Sugar Chlorosulfates: Part V. The Synthesis of Chlorodeoxy Sugars

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The treatment of methyl a-D-xylopyranoside 2,3,4-tri(ch1orosulfate) with aluminum chloride yielded a mixture of two major components identified as methyl a-D-xylopyranoside 2,3,4-tri(chlorosulfate) and 4-0-methyl-a-L-arabinopyranosyl chloride 2,3-di(chlorosulfate). The latter compound constituted about 25 % of the mixture and was formed as a result of the preferential migration of the anomeric methoxy group to C-4 of the pyran ring. Similar treatment of methyl a-D-glucopyranoside 2,3,4,6-tetra(chlorosulfate) with aluminum chloride yielded crystalline 6-0-methyl-a-D-glucopyranosyl chloride 2,3,4-tri(ch10-rosulfate) as the only major methoxy migration product. This methoxy migration occurred to the extent of 66% and in contrast to the results obtained with methyl pentapyranoside derivative the anomeric methoxy group migrated preferentially to C-6 in this case. The factors controlling these highly selective methoxy migrations are discussed.

Section: Methodsmentioning

confidence: 99%

Methoxy group migrations in the reaction of some methyl-pyranoside chlorosulfate ester derivatives with aluminum chloride

Gibbs¹,

Jennings²

1970

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“…La rtaction du chlorure de sulfuryle sur les sucres rtducteurs, A basse temptrature, conduit dans les conditions d'isolement dtcrites par Jennings et Jones (1,2) A des trichloro-1,4,6 tridtsoxy-1,4,6 dichlorosulfate-2,3 hexopyrannose pour les hexopyrannoses et 2 des dichloro-1,4 dichlorosulfate-2,3 pentopyrannose pour les pentoses. Par modification des conditions d'isolement, Jennings dtcrit ~~lttrieurement (3-5) la preparation de chloro-1 trichlorosulfate-2,3,4 pentopyrannose.…”

Section: Introductionunclassified

Synthèse d'α-L-Fucopyrannosides

Rafestin¹,

Delay²,

Monsigny³

1974

R e~u le 12 juin 1973Le chloro-1 trichlorosulfate-2,3,4 B-L-fucopyrannose (1) est prCparC par rCaction du chlorure de sulfuryle sur le L-fucose, a basse temptrature (rendement, 47%). Le chloro dCrivC (1) rCagit sur les alcools en conduisant principalement a I'a-L-fucoside correspondant. Le p-nitrobenzyl a-L-fucoside est obtenu avec un rendement de 35%, a partir de (1). A partir du L-fucose, I'a-L-fucoside est obtenu en trois Ctapes seulement.The B-L-fucopyranosyl chloride 2,3,4-tri(chlorosulfate) (1) has been prepared by reaction of sulfuryl chloride with L-fucose at low temperature (yield, 47%). This B-L-fucopyranosyl chloride (1) gave high yields of the a-L-fucoside by reaction with alcohols. The p-nitrobenzyl a-L-fucoside has been prepared (yield, 35%). From L-fucose, the a-L-fucoside is obtained in three steps.

“…Elemental analysis showed the formation of a dichlorodideoxy compound, and periodate oxidation results indicated that the chlorodeoxy groups were a t the C-3 and C-6 positions. The D-all0 configuratioil is assumed, since in all cases examined hitherto the chlorodeoxy groups were observed to be introduced with inversion (3)(4)(5).…”

Section: Introductionmentioning

confidence: 99%

Reactions of Sugar Chlorosulfates: Vii. Some Conformational Aspects

Cottrell¹,

Buncel²,

Jones³

1966

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The reaction of sulfuryl chloride with several 1,6-anhydro-hexosa~ls has yielded crystalli~le, fully chlorosulfated derivatives. lieplacement of the chlorosulfate moieties by chlorodeoxy groups could not be achieved under the reaction conditions employed. This non-reactivity is discussed in terms of steric interactions in the transition state for substitution.An examination of some chloro-substituted sugar chlorosulfates conhrmed that an axial chlorodeoxy group in a glycopyranoside deactivates a neighboring equatorial chlorosulfate group and thus prevents further chlorodeoxy groups being introduced into such positions. Methyl a-D-altropyra~~oside, methyl a-L-rhamnopyranoside, methyl a-D-lyxopyranoside, L-rhamnose, and D-lyxose were reacted with sulfuryl chloride. The resulting products were those expected if these sugars reacted primarily in the C1 conformation.