Methyl 2,3-anhydro-a-D-allopyranoside

The Action of Alkali on Methyl 2 3-Anhydro-a-D-allopyranoside and l 5-Anhydro-2-deoxy-3-0-toluene-p-sulphonyl-D-arabino-hexitol," A. B. Foster, M. Stacey, and S. V. Vardheim, Acta Chem. Scand., 12(1958) 1819-1824. 

With sodium hydroxide, methyl 2,3-anhydro-a-D-allopyranoside yields methyl 3,6-anhydro-a-D-glucopyranoside by intramolecular attack on the epoxide ring by the 6-hydroxyl group.72 Methyl 2,3-anhydro-a-D-gulopyranoside behaves similarly, and its intermediacy accounts for the conversion of methyl 3,4-anhydro-a-D-galactopyrano-side into methyl 3,6-anhydro-a-D-galactopyranoside on treatment with alkali.67... 

Methyl 2,4-di-0-acetyl-3-am.ino-3,6-dideoxy-a-L-glucopyranoside, A-381 Methyl 4,6-di-0-acetyl-2,3-anhydro-a-D-allopyranoside, A-484 Methyl 3,4-di-0-acetyl-2,6-anhydro-a-D-altropyranoside, A-494 Methyl 3,4-di-0-acetyl-2,6-anhydro-p-D-altropyranoside, A-494 Methyl 3,4-di-O-acetyl-2,6-anhydro-5-deoxy-D-/yx -hex-5-enoate, A-541 Methyl 3,5-di-0-acetyl-l,4-anhydro-p-D-fructopyranoside, A-605 Methyl 2,5-di-0-acetyl-3,6-anhydro-a-L-gulofuranoside, A-640 Methyl 2,5-di-0-acetyl-3,6-anhydro-p-L-gulofuranoside, A-640 Methyl 2,5-di-0-acetyl-3,6-anhydro-a-L-idofuranoside, A-659 Methyl 2,5-di-0-acetyl-3,6-anhydro-p-L-idofuranoside, A-659 Methyl 3,4-di-0-acetyl-2,6-anhydro-a-D-idopyranoside, A-658 Methyl 3,4-di-0-acetyl-2,6-anhydro-p-D-idopyranoside, A-658 Methyl 3,4-di-0-acetyl-2,6-anhydro-a-D-inannopyranoside, A-678 Methyl 3,4-di-0-acetyl-2,6-anhydro-p-D-inannopyranoside, A-678 Methyl l,6-di-0-acetyl-3,4-anhydro-a-D-tagatofuranoside, A-701 Methyl l,6-di-0-acetyl-3,4-anhydro-p-D-tagatofuranoside, A-701 Methyl 3,4-di-0-acetyl-2,6-anhydro-a-D-talopyranoside, A-710 Methyl 3,4-di-0-acetyl-2,6-anhydro-p-D-talopyranoside, A-710 Methyl 2,6-di-0-acetyl-3,4-anhydro-a-DL-talopyranoside, A-711 Methyl 4,6-di-O-acetyl-3-azido-2,3-dideoxy-a-D-ara >m< -hexopyranoside, A-918... 

Benzyl 2,3-anhydro-4-0-a-L-arabinopyranosyl-p-D-ribopyranoside, A-848 Benzyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside, A-484 Benzyl 2,3-anhydro-4,6-0-benzylidene-p-D-gulopyranoside, A-639 Benzyl 2,3-anhydro-4,6-0-benzylidene-a-D-mannopyranoside, A-676 Benzyl 3,4-anhydro-2,6-dideoxy-a-L-r -hexopyranoside, A-591 Benzyl 2,3-anhydro-4- O - p-D-galactopyranosyl- p-D-ribopyranoside, G-173 Benzyl 2,3-anhydro-a-D-mannopyranoside, A-676 Benzyl 2,3-anhydro-p-D-mannopyranoside, A-676 Benzyl 3,4-anhydro-2-0-mesyl-6-0-trityl-a-D-altropyranoside, A-495 Benzyl 2,3-anhydro-4-0-methyl-p-D-ribopyranoside, A-693 Benzyl 2,3-anhydro-p-D-ery /iro-pentopyranosid-4-ulose, A-682 Benzyl 2,3-anhydro-p-L-eyy /iro-pentopyranosid-4-ulose, A-682 Benzyl 2,3-anhydro-a-D-ribopyranoside, A-693 Benzyl 2,3-anhydro-p-D-ribopyranoside, A-693 Benzyl 2,3-anhydro-p-L-ribopyranoside, A-693... 

Oxirans. - Treatment of methyl 4,6-0-benzylidene-a-D-glucopyranoside with a mixture of diethyl carbonate and potassium carbonate in DMF has afforded directly a new simple synthesis of methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside. The corresponding 2,3-cyclic carbonate is postulated as an intomediate. Some carbohydrate examples have been published of the use of sodium hydride and p-toluenesulfonyl chloride for the conversion of 1,2-diols to epoxides. Simple routes to the Cemy epoxides 6 and 7 finom D-glucal have been develc red (Scheme 1). In this scheme the flrst step involves a dehydration elimination with allylic rearrangement Syntheses of methyl 2,3-anhydro-a- and L-OTthiofuranoside have been reported. Some nitro-sugar epoxides are mentioned in Chapter 10. 

C17H23Br09 Methyl 2,3-anhydro-6-bromo-6-deoxy-4-0-(4,6-di-0-ace-tyl-2,3-dideoxy-a-D-erythro-hex-2-enopyranosyl)-a-D-allopyranoside (MBEHAP)98... 

In the aldohexopyranose series, treatment of methyl 2,3-anhydro-4,6-di-O-methyl-a-D-allopyranoside (34), or of the corresponding 4,6-diacetate (39), with hydrogen tetrafluoroborate in hydrogen fluoride at 70° afforded121 the corresponding derivatives of 2-deoxy-2-fluoro-D-al-tropyranosyl fluoride (35 and 40) and 3-deoxy-3-fluoro-D-glucopyrano-syl fluoride (36 and 41). Compounds 35 and 36 were hydrolyzed, and... 

A novel method of opening of oxiranes involves the use of (chlo-romethylene)dimethyliminium chloride (39) [see Section II,2c p. 250], monochlorodeoxy or dichlorodideoxy derivatives are obtained, depending upon the reaction conditions employed.83 Thus, methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside (110) reacts with 39 in 1,1,2,2-tetrachloroethane at room temperature to give, upon hydrolysis of the primary adduct 111 with an aqueous solution of sodium hydrogen carbonate, methyl 4,6-0-benzylidene-2-chloro-2-deoxy-3-0-formyl-a-D-altropyranoside (112). If a solution of 39 and 110 in 1,1,2,2-tetrachloroethane is heated at reflux temperature, methyl 3,4-0-benzylidene-2,6-dichloro-2,6-dideoxy-o -D-altropyrano-side (113) is obtained in high yield the n.m.r. spectrum of 113, like that of 47 (see Section II, 2c p. 250), showed the presence of two diastereoisomers which differed in the configuration of the benzyl-idene-acetal carbon atom. 

As might be expected, the nitrous acid deamination of methyl 2-amino-4,6-0-benzylidene-2-deoxy-a-D-altropyranoside (10) hydrochloride leads45,46 uniquely to methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside (11). The benzylidene group does not play an... 

H. W. C. Raaijmakers, B. Zwanenburg, and G. J. F. Chittenden, An alternative synthesis of methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside using carbonate esters, Carbohydr. Res., 238 (1993) 185-192. 

Treatment of an epoxide, namely methyl 2,3-anhydro-4,6-0-benzylidene-oi-D-allopyranoside (78, Scheme 21), with nitryl iodide using methanol as the solvent has been reported.123 Rather than the expected nitration, opening of the epoxide occurred to afford 30% of methyl 4,6-0-benzylidene-3-0-methyl-oi-D-glucopyranoside (79), 10% of methyl 4,6-0-benzylidene-2-0-methyl-a-D-altropyranoside (80), and a water-soluble material. The water-soluble material was later determined to be a mixture of the 2-0- (81) and 3-0-methyl (82) products, with the benzylidene acetal removed, a result consistent with a later study.124 Performing the reaction in the absence of the silver salt resulted solely in formation of the water-soluble product. The preponderance of the diequatorial product 81 is in violation of the Flirst-Plattner rule, which predicts more of the diaxial product. The authors explanation for the anti-Fiirst-Plattner addition is as follows. 

Very significant results have been reported"sodium hydride. The resultant cyclopropane derivative (238a) was... 

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