Allopyranoside 3-chloro-3-deoxy

Reactivity at 0-3, in addition to that at 0-4 and 0-6, was observed with methyl )3-D-galactopyranoside, which, when treated with sulfuryl chloride, yielded methyl 3,4,6-trichloro-3,4,6-trideoxy-/J-D-allopyranoside 2-(chlorosulfate) in 56% yield.352 In contrast, under similar conditions, methyl a-D-galactopyranoside gave352 methyl 4,6-dichloro-4,6-dideoxy-a-D-glucopyranoside 2,3-di(chlorosulfate). Further examples of the dependence of the reactivity on the configuration of C-l are the conversion of methyl 4,6-0-benzylidene-/3-D-glucopyranoside into methyl 4,6-0-benzylidene-3-chloro-3-deoxy-/3-i>allopyranoside by sulfuryl chloride,352 and of methyl 4,6-0-benzylidene-a-D-glucopyranoside, under similar conditions, into the 2,3-di(chlorosulfate).355... 

An important step in the synthesis of paratose (3,6-dideoxy-n-rtfoo-hexose) involved the conversion of methyl 3-chloro-3-deoxy-/8-D-allopyranoside into methyl 3,6-dichloro-3,6-dideoxy-/8-D-allo-pyranoside in 33% yield.359... 

On treatment with 30 equivalents of methanesulfonyl chloride in N,N-dimethylformamide for 8 days at 65°, methyl /3-maltoside gave a mixture of methyl 3,6-dichloro-4-0-(6-chloro-6-deoxy-a-D-glucopyranosyl)-3,6-dideoxy-/3-D-allopyranoside, isolated in 46%... 

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. 

A solution of methyl 4,6-Obenzylidene-3-chloro-3-deoxy-P-D-allopyranoside [29] (33, 2.45 g) in acetone (40 mL) and 0.2 N hydrochloric acid (13 mL) was heated at reflux temperature for 4 h. The acetone was removed by distillation, and the aqueous solution was neutralized with Duolite A-4(OH ) ion-exchange resin and concentrated to yield methyl 3-chloro-3-deoxy-p-D-allopyranoside as a chromatographically homogeneous (TLC) syrup [41] (1.56 g), Rt 0.5 [6 2 1 (v/v/v) 1-butanol-ethanol-water], [a]D —49° (c 1.0, H20). This syrupy product (1.39 g) was converted into methyl 3,6-dichloro-3,6-dideoxy-p-D-allo-pyranoside 25 as described by Cottrell et al. [44J. The crystalline product was recrystallized from chloroform-petroleum ether to give the final product (0.5 g, 33%) mp 162°-163°C, [a]D -43° (c 0.6, CHClj) reported [44] mp 154°-156°C, [a]D -45° (c 1.0, CHC13). 

A solution of methyl 4,6-0-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside [29] (33, 12.6 g) in dry tetrahydrofuran (500 mL) containing sodium benzoate (12 g) was boiled for 2 h under reflux. The cooled suspension was filtered, and the filtrate was evaporated to dryness. The residue was extracted with chloroform, and the extract was washed with water, dried (MgS04), and evaporated to dryness. Crystallization of the product from chloroform-petroleum ether gave methyl 4,6-0-benzylidene-P-D-eryriiro-hex-3-enopyranoside 43, yield 8.8 g (85%), mp 134°-135°C, [ot]D -43° (c 1.58, CHC13). 

E. H. Williams, W. A. Szarek, and J. K. N. Jones, Iheparation of unsaturated carbohydrates from methyl 4,6-0-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside, and their utility in the synthesis of sugars of biological importance, Carbohydr. Res. 20 49 (1971). 

A special example of epoxide opening reaction is outlined in O Scheme 40. Methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside 72 gives the 2-chloro-2-deoxy-3-0-formyl-altroside 73 on treatment of (chloromethylene)dimethyliminium chloride at room temperature. Alternatively, when the reaction mixture is heated for a longer time, methyl 3,4-0-benzyli-dene-2,6-dichloro-2,6-dideoxy-a-D-altroside 74 is obtained by means of a rearrangement of the benzylidene group [51]. 

Me glycoside Methyl 2-chloro-2-deoxy-a-D-allopyranoside C7H13CIO5 212.629 Cryst. Mp 160-161°. [ ]d +111 (MeOH). 

Me glycoside, 3,4-O-benzylidene Methyl 3,4-0-(K)-benzylidene-2-chloro-2-deoxy-a-D-allopyranoside [35775-03-2]... 

Me glycoside, 3,4-O-isopropyUdene Methyl 2-chloro-2-deoxy-3,4-0-isopropylidene-ot-D-allopyranoside C10H17CIO5 252.694 Mp 60°. [ ]d +75.9 (CHCI3). 

Ac Methyl 2-0-acetyl-4,6-0-(K)-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside [131474-43-6]... 

Methyl 2,3-anhydro-4-bromo-4-deoxy-a-L-lyxopyranoside, B-84 Methyl 2,3-anhydro-4-bromo-4-deoxy-6- O -trityl-a-D-gulopyranoside, B-78 Methyl 2,3-anhydro-4-chloro-4-deoxy-a-L-xylopyranoside, C-110 Methyl 2,3-anhydro-6-deoxy-a-D-allopyranoside, A-516 Methyl 2,3-anhydro-6-deoxy-a-L-allopyranoside, A-516 Methyl 3,6-anhydro-2-deoxy-4,5 7,8-di-0-isopropylidene-D-g-/ycer(3-D-ia/o-octonate, M-174... 

Methyl 3,4-0 -(R)-benzylidene-2-chloro-2-deoxy-a-D-allopyranoside, C-70 Methyl 4,6-0-benzylidene-2-chloro-2-deoxy-a-D-allopyranoside, C-70 Methyl 4,6-0-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside, C-71 Methyl 4,6-0 -(R)-benzylidene-3-chloro-3-deoxy-a-D-altropyranoside, C-73 Methyl 4,6-0-benzylidene-2-chloro-2-deoxy-a-D-glucopyranoside, C-85 Methyl 4,6-0-benzylidene-2-chloro-2-deoxy-p-D-glucopyranoside, C-85 Methyl 4,6-0-benzylidene-2-chloro-2-deoxy-a-D-idopyranoside, C-91 Methyl 4,6-0 -benzylidene-2-chloro-2-deoxy-3-0-methyl-a-D-allopyranoside, C-70... 

Methyl 3-acetamido-3-deoxy-a-D-allofnranoside, A-157 Methyl 3-acetamido-3-deoxy-p-D-allofnranoside, A-157 Methyl 4-acetamido-4,6-dideoxy-a-D-allopyranoside, A-365 Methyl 4-acetamido-4,6-dideoxy-p-D-allopyranoside, A-365 Methyl 3-acetamido-2,5,6-tri-0-acetyl-3-deoxy-p-D-allofuranoside, A-157 Methyl 3-acetamido-2,4,6-tri-0-acetyl-3-deoxy-a-D-allopyranoside, A-157 Methyl 3-acetamido-2,4,6-tri-0-acetyl-3-deoxy-p-D-allopyranoside, A-157 Methyl 2-0-acetyl-4,6-0-benzylidene-a-D-allopyranoside, M-155 Methyl 2-0-acetyl-4,6-0-(J )-benzylidene-3-chloro-3-deoxy-p-D-allopyranoside, C-71 Methyl a-D-allofuranoside, M-148 Methyl p-D-allofuranoside, M-148 Methyl a-D-allopyranoside, M-148 Methyl p-D-allopyranoside, M-148 Methyl 3-amino-3-deoxy-p-D-allofnranoside, A-157 Methyl 3-amino-3-deoxy-a-D-allopyranoside, A-157 Methyl 3-amino-3-deoxy-p-D-allopyranoside, A-157 Methyl 4-amino-4,6-dideoxy-a-D-allopyranoside, A-365 Methyl 4-amino-4,6-dideoxy-p-D-allopyranoside, A-365 Methyl 5,6-anhydro-2,3-0-isopropylidene-p-L-allofuranoside, M-148 Methyl 2-0-benzoyl-4,6-0-benzylidene-a-D-allopyranoside, M-155 Methyl 6-O-benzoyl-3,4-O -isopropylidene-2-O-tosyl-a-D-allopyranoside, M-148... 

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