Methyl 2,3,4-tri-O-benzyl-alpha-D-glucopyranoside

Conditions: temp:-30.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethereal silver perchlorate (0.08 M, 76.9 mL, 6.15 mmol) is added with stirring at -30° C. to a solution of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.078 g, 4.48 mmol), 4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl chloride (2.859 g, 5.6 mmol) and 2,4,6-trimethylpyridine (0.81 mL, 6.15 mmol) in ether (20 mL). The mixture is stirred 15 min at -30° C. and silver chloride precipitated. The mixture is filtered through a celite pad, the solids are washed with ether, the filtrate is concentrated under reduced pressure. The residue is dissolved in methylene chloride and the organic layer is washed successively with aqueous sodium thiosulfate and water. The organic layer is dried over sodium sulfate, filtered and concentrated under reduced pressure so as to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate will afford methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl)-2,3,4-tri-O-benzyl-α-D-glucopyranoside as a foam. silver chloride precipitated The mixture is filtered through a celite pad the solids are washed with ether the filtrate is concentrated under reduced pressure The residue is dissolved in methylene chloride the organic layer is washed successively with aqueous sodium thiosulfate and water The organic layer is dried over sodium sulfate filtered concentrated under reduced pressure so as to afford a foam Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate

Conditions: temp:-30.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethereal silver perchlorate (0.08 M, 76.9 mL, 6.15 mmol) is added with stirring at -30° C. to a solution of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.078 g, 4.48 mmol), 4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl chloride (2.859 g, 5.6 mmol) and 2,4,6-trimethylpyridine (0.81 mL, 6.15 mmol) in ether (20 mL). The mixture is stirred 15 min at -30° C. and silver chloride precipitated. The mixture is filtered through a celite pad, the solids are washed with ether, the filtrate is concentrated under reduced pressure. The residue is dissolved in methylene chloride and the organic layer is washed successively with aqueous sodium thiosulfate and water. The organic layer is dried over sodium sulfate, filtered and concentrated under reduced pressure so as to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate will afford methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl)-2,3,4-tri-O-benzyl-α-D-glucopyranoside as a foam. silver chloride precipitated The mixture is filtered through a celite pad the solids are washed with ether the filtrate is concentrated under reduced pressure The residue is dissolved in methylene chloride the organic layer is washed successively with aqueous sodium thiosulfate and water The organic layer is dried over sodium sulfate filtered concentrated under reduced pressure so as to afford a foam Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate

Conditions: temp:-35.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of oxalyl chloride (1.05 mL, 17.22 mmol) in dry tetrahydrofuran (40 mL) cooled to -78° C., dry dimethyl sulfoxyde (1.3 mL, 18.04 mmol) was added dropwise and then stirred during 35 min at -35° C. The reaction mixture was cooled again to -78° C. and methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (6 g, 16.4 mmol) dissolved in tetrahydrofuran (20 mL) was added and the mixture was stirred during 15 min at -35° C., then triethylamine (11.5 mL, 82.65 mmol) was added and the mixture was stirred during 1 h at -35° C. This aldehyde was used without purification and isolation in a Wittig reaction described as follows. To dried triphenylmethylphosphonium bromide (11.7 g, 32.8 mmol) suspended in tetrahydrofuran (700 mL) was added dropwise at -78° C. a 1.42 M solution of n-butyllithium in hexane (23 mL, 32.66 mmol). The reaction mixture was warmed to room temperature and stirred during 1.5 h. Then the mixture was cooled to 0° C. and potassium tertio-butylate (3.68 g, 32.8 mmol) and dry tertio-butyl alcohol (3mL, 31.8 mmol) were added. The mixture was stirred again at room temperature during 30 min. The reaction mixture was cooled to -78° C. and the tetrahydrofuran solution of the aldehyde prepared above was added dropwise. The reaction mixture was warmed to room temperature and stirred during 2 h. A saturated aqueous solution of ammonium chloride and the solvents were evaporated under reduced pressure. The residue was dissolved in ether and washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford a brown oil. Flash chromatography on silica gel and elution with a 4:96 mixture of ethyl acetate and toluene afforded the expected olefine methyl 2,3,4-tri-O-benzyl-6,7-dideoxy-α-D-glucohept-6-enopyranoside (3.26 g, 55%) which crystallized from hexane; m.p. 46°-47° C. The reaction mixture was cooled again to -78° C. was added the mixture was stirred during 15 min at -35° C. the mixture was stirred during 1 h at -35° C This aldehyde was used without purification and isolation in a Wittig reaction The reaction mixture was warmed to room temperature stirred during 1.5 h Then the mixture was cooled to 0° C. were added The mixture was stirred again at room temperature during 30 min The reaction mixture was cooled to -78° C. above was added dropwise The reaction mixture was warmed to room temperature stirred during 2 h A saturated aqueous solution of ammonium chloride and the solvents were evaporated under reduced pressure The residue was dissolved in ether washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford a brown oil Flash chromatography on silica gel and elution with a 4:96 mixture of ethyl acetate and toluene

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of dry pyridine (0.46 mL) in methylene chloride (17.5 mL) cooled to -15° C. was added trifluoromethanesulfonic anhydride (0.87 mL). The mixture was stirred during 15 min at -10° C., then methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (1.2 g, 2.58 mmol) in methylene chloride (5 mL) was added (P. Kovac, V. Sklenar and C. Glaudemans, Carbohydr. Res. 175, 201 (1988)). The mixture was stirred during 1.5 h at -10° C. The reaction mixture was washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford an oil. Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate afforded the expected compound methyl 2,3,4-tri-O-benzyl-6-O-trifluoromethylsulfonyl-α-D-glucopyranoside which was crystallized from hexane (1.43 g, 93%); m.p. 44°-45° C. The mixture was stirred during 1.5 h at -10° C The reaction mixture was washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford an oil Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of dry pyridine (0.46 mL) in methylene chloride (17.5 mL) cooled to -15° C. was added trifluoromethanesulfonic anhydride (0.87 mL). The mixture was stirred during 15 min at -10° C., then methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (1.2 g, 2.58 mmol) in methylene chloride (5 mL) was added (P. Kovac, V. Sklenar and C. Glaudemans, Carbohydr. Res. 175, 201 (1988)). The mixture was stirred during 1.5 h at -10° C. The reaction mixture was washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford an oil. Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate afforded the expected compound methyl 2,3,4-tri-O-benzyl-6-O-trifluoromethylsulfonyl-α-D-glucopyranoside which was crystallized from hexane (1.43 g, 93%); m.p. 44°-45° C. The mixture was stirred during 1.5 h at -10° C The reaction mixture was washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford an oil Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate

Conditions: temp:-30.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethereal silver perchlorate (0.08 M, 76.9 ml, 6.15 mmol) is added With stirring at -30° C. to a solution of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.078 g, 4.48 mmol), 4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl chloride (2,859 g, 5.6 mmol) and 2,4,6-trimethylpyridine (0.81 ml, 6.15 mmol) in ether (20 ml). The mixture is stirred 15 min at -30° C. and silver chloride precipitated. The mixture is filtered through a celite pad, the solids are washed with ether, the filtrate is concentrated under reduced pressure. The residue is dissolved in methylene chloride and the organic layer is washed successively with aqueous sodium thiosulfate and water. The organic layer is dried over sodium sulfate, filtered and concentrated under reduced pressure so as to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate will afford methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl)-2,3,4-tri-O-benzyl-α-D-glucopyranoside as a foam. silver chloride precipitated The mixture is filtered through a celite pad the solids are washed with ether the filtrate is concentrated under reduced pressure The residue is dissolved in methylene chloride the organic layer is washed successively with aqueous sodium thiosulfate and water The organic layer is dried over sodium sulfate filtered concentrated under reduced pressure so as to afford a foam Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate

Conditions: temp:-30.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethereal silver perchlorate (0.08M, 76.9 mL, 6.15 mmol) was added with stirring at -30° C. to a solution of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.078 g, 4.48 mmol), 4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl chloride (2.859 g, 5.6 mmol) and 2,4,6-trimethylpyridine (0.81 mL, 6.15 mmol) in ether (20 mL). The mixture was stirred 15 min at -30° C. and silver chloride precipitated. The mixture was filtered through a celite pad, the solids were washed with ether, the filtrate was concentrated under reduced pressure. The residue was dissolved in methylene chloride and the organic layer was washed successively with aqueous sodium thiosulfate and water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate afforded methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl) -2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.314 g, 55%) as a foam. silver chloride precipitated The mixture was filtered through a celite pad the solids were washed with ether the filtrate was concentrated under reduced pressure The residue was dissolved in methylene chloride the organic layer was washed successively with aqueous sodium thiosulfate and water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford a foam Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate

Conditions: temp:-35.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of oxalyl chloride (1.05 mL, 17.22 mmol) in dry tetrahydrofuran (40 mL) cooled to -78° C., dry dimethyl sulfoxyde (1.3 mL, 18.04 mmol) was added dropwise and then stirred during 35 min at -35° C. The reaction mixture was cooled again to -78° C. and methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (6 g, 16.4 mmol) dissolved in tetrahydrofuran (20 mL) was added and the mixture was stirred during 15 min at -35° C., then triethylamine (11.5 mL, 82.65 mmol) was added and the mixture was stirred during 1 h at -35° C. This aldehyde was used without purification and isolation in a wittig reaction described as follows. To dried triphenylmethylphosphonium bromide (11.7 g, 32.8 mmol) suspended in tetrahydrofuran (700 mL) was added dropwise at -78° C. a 1.42M solution of n-butyllithium in hexane (23 mL, 32.66 mmol). The reaction mixture was warmed to room temperature and stirred during 1.5 h. Then the mixture was cooled to 0° C. and potassium tertiobutylate (3.68 g, 32.8 mmol) and dry tertio-butyl alcohol (3 mL, 31.8 mmol) were added. The mixture was stirred again at room temperature during 30 min. The reaction mixture was cooled to -78° C. and the tetrahydrofuran solution of the aldehyde prepared above was added dropwise. The reaction mixture was warmed to room temperature and stirred during 2 h. A saturated aqueous solution of ammonium chloride and the solvents were evaporated under reduced pressure. The residue was dissolved in ether and washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford a brown oil. Flash chromatography on silica gel and elution with a 4:96 mixture of ethyl acetate and toluene afforded the expected olefine methyl 2,3,4-tri-O-benzyl-6,7-dideoxy-α-D-glucohept-6-enopyranoside (3.26 g, 55%) which crystallized from hexane; m.p. 46°-47° C. The reaction mixture was cooled again to -78° C. was added the mixture was stirred during 15 min at -35° C. the mixture was stirred during 1 h at -35° C This aldehyde was used without purification and isolation in a wittig reaction The reaction mixture was warmed to room temperature stirred during 1.5 h Then the mixture was cooled to 0° C. were added The mixture was stirred again at room temperature during 30 min The reaction mixture was cooled to -78° C. above was added dropwise The reaction mixture was warmed to room temperature stirred during 2 h A saturated aqueous solution of ammonium chloride and the solvents were evaporated under reduced pressure The residue was dissolved in ether washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford a brown oil Flash chromatography on silica gel and elution with a 4:96 mixture of ethyl acetate and toluene

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of dry pyridine (0.46 mL) in methylene chloride (17.5 mL) cooled to -15° C. was added trifluoromethanesulfonic anhydride (0.87 mL). The mixture was stirred during 15 min at -10° C., then methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (1.2 g, 2.58 mmol) in methylene chloride (5 mL) was added [P. Kovac, V. Sklenar and C. Glaudemans, Carbohydr. Res. 175, 201 (1988)]. The mixture was stirred during 1.5 h at -10° C. The reaction mixture was washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford an oil. Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate afforded the expected compound methyl 2,3,4-tri-O-benzyl-6-O-trifluoromethylsulfonyl-α-D-glucopyranoside which was crystallized from hexane (1.43 g, 93%); m.p. 44°-45° C. The mixture was stirred during 1.5 h at -10° C The reaction mixture was washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford an oil Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of dry pyridine (0.46 mL) in methylene chloride (17.5 mL) cooled to -15° C. was added trifluoromethanesulfonic anhydride (0.87 mL). The mixture was stirred during 15 min at -10° C., then methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (1.2 g, 2.58 mmol) in methylene chloride (5 mL) was added [P. Kovac, V. Sklenar and C. Glaudemans, Carbohydr. Res. 175, 201 (1988)]. The mixture was stirred during 1.5 h at -10° C. The reaction mixture was washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford an oil. Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate afforded the expected compound methyl 2,3,4-tri-O-benzyl-6-O-trifluoromethylsulfonyl-α-D-glucopyranoside which was crystallized from hexane (1.43 g, 93%); m.p. 44°-45° C. The mixture was stirred during 1.5 h at -10° C The reaction mixture was washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford an oil Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of dry pyridine (0.46 ml) in methylene chloride (17.5 ml) cooled to -15° C. was added trifluoromethanesulfonic anhydride (0.87 ml). The mixture was stirred during 15 min at -10° C. then methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (1.2 g, 2.58 mmol) in methylene chloride (5 ml) was added (P. Kovac, V. Sklenar and C. Glaudemans, Carbohydr. Res., 175, 201 (1988)). The mixture was stirred during 1.5 h at -10° C. The reaction mixture was washed with water. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to afford an oil. Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate afforded the expected compound methyl 2,3,4-tri-O-benzyl-6-O-trifluoromethylsulfonyl-α-D-glucopyranoside which was crystallized from hexane (1.43 g, 93%); m.p. 44°-45° C. The mixture was stirred during 1.5 h at -10° C The reaction mixture was washed with water The organic layer was dried over sodium sulfate filtered concentrated under reduced pressure to afford an oil Flash chromatography on silica gel and elution with a 7:3 mixture of hexane and ethyl acetate

Conditions: temp:-30.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethereal silver perchlorate (0.08 M, 76.9 mL, 6.15 mmol) is added with stirring at -30° C. to a solution of methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (2.078 g, 4.48 mmol), 4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl chloride (2.859 g, 5.6 mmol) and 2,4,6-trimethylpyridine (0.81 mL, 6.15 mmol) in ether (20 mL). The mixture is stirred 15 min at -30° C. and silver chloride precipitated. The mixture is filtered through a celite pad, the solids are washed with ether, the filtrate is concentrated under reduced pressure. The residue is dissolved in methylene chloride and the organic layer is washed successively with aqueous sodium thiosulfate and water. The organic layer is dried over sodium sulfate, filtered and concentrated under reduced pressure so as to afford a foam. Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate will afford methyl 6-O-(4-O-acetyl-2,3,6-tri-O-benzyl-α-D-galactopyranosyl)-2,3,4-tri-O-benzyl-α-D-glucopyranoside as a foam. silver chloride precipitated The mixture is filtered through a celite pad the solids are washed with ether the filtrate is concentrated under reduced pressure The residue is dissolved in methylene chloride the organic layer is washed successively with aqueous sodium thiosulfate and water The organic layer is dried over sodium sulfate filtered concentrated under reduced pressure so as to afford a foam Flash chromatography on silica gel and elution with a graded mixture of hexane and ethyl acetate