M. A. J. Buffet et al. / Carbohydrate Research 339 (2004) 2507–2513
2511
˚
dered 4A molecular sieves (0.4g) were added and after
by chromatography using 5:1 hexane–ethyl acetate as
eluant. Compound 9 was obtained as a syrup (0.616g,
77.4%); ½aꢀ
the mixture was stirred under N2 at 0ꢁC for 1.5h. BF3Æ
Et2O (0.10mL, 0.77mmol) was added. After being stir-
red for an additional 10min the reaction mixture was
neutralized with Et3N, diluted with CH2Cl2, and filtered
through Celite. The filtrate was washed successively with
H2O and brine. The filtrate was dried over Na2SO4, fil-
tered, and concentrated to dryness and purified by chro-
matography using 5:1 hexane–ethyl acetate as eluant.
Compound 9 was obtained as a syrup (0.158g, 41.4%).
25
D
+19.5 (c 0.78, CHCl3); 1H NMR
(300.13MHz, CDCl3): dH, 7.8–7.2 (m, 15H, aromatic),
5.48 (br s, 1H, H-2 Api), 5.24 (br s, 1H, H-1 Api),
4.66 (d, 1H, J1,2 3.6Hz, H-1 Gal), 4.60, 4.51 (2d, 2H,
JHa,Hb 12.2Hz, OCH2Ph), 4.23 (1H, H-4 Gal), 4.18,
3.96 (2d, 2H, J4a,4b 11.1Hz, H-4a, H-4b Api), 4.18 (s,
2H, H-30a, H-30b Api), 4.17 (1H, H-3 Gal), 3.99 (1H,
H-5 Gal), 3.92, 3.84 (2H, H-6a, H-6b Gal), 3.68 (dd,
1H, J2,3 7.9Hz, H-2 Gal), 3.28 (s, 3H, OCH3), 2.09,
2.06 (2s, 6H, OCOCH3), 1.50, 1.33 (2s, 6H, C(CH3)2),
1.06 (s, 9H, C(CH3)3); 13C NMR (75.03MHz, CDCl3):
dC, 170.2, 169.2 (C@O acetate), 138.2, 135.8, 133.7,
129.9, 128.6, 127.9, 127.8, 127.7 (aromatic), 109.3
(C(CH3)2), 106.4 (C-1 Api), 99.2 (C-1 Gal), 85.9 (C-3
Api), 77.2 (C-2 Api), 76.3 (C-2 Gal), 75.4 (C-3 Gal),
73.6 (OCH2Ph, C-30 Api), 73.4 (C-4 Gal), 70.1 (C-4
Api), 67.7 (C-5 Gal), 63.1 (C-6 Gal), 55.5 (OCH3),
28.5, 26.6 (C(CH3)2), 27.0 (C(CH3)3), 21.9, 21.5
(OCOC3). Anal. Calcd for C42H54O12Si: C, 64.76; H,
6.99. Found: C, 64.40; H, 7.01.
3.3.2. Table 1, entry 2. Samples of 411 (0.0695g,
0.190mmol) and 814 (0.0767g, 0.162mmol) were dis-
˚
solved in CH2Cl2 (10.0mL). Powdered 4A molecular
sieves (0.1g) were added and after the mixture was stir-
red under N2 at 25ꢁC for 45min trimethylsilyl trifluoro-
methanesulfonate (5lL, 0.03mmol) was added to the
mixture. After being stirred for an additional 10min,
the reaction mixture was neutralized with Et3N, diluted
with CH2Cl2, and filtered through Celite. The filtrate
was washed successively with satd aq NaHCO3 and
H2O. The filtrate was dried over Na2SO4, filtered, and
concentrated to dryness and purified by chromatogra-
phy using 2:1 hexane–ethyl acetate as eluant. Com-
pound 9 was obtained as a syrup (0.0742g, 58.7%).
3.4. Methyl (2,3-di-O-acetyl-3-C-(benzyloxymethyl)-b-D-
erythrofuranosyl)-(1fi2)-3,4-O-isopropylidene-a-D-gal-
actopyranoside (10)
3.3.3. Table 1, entry 3. A mixture of thioglycoside 612
(0.0836g, 0.226mmol) and galactose derivative 814
(0.0840g, 0.178mmol) was dissolved in CH2Cl2
Disaccharide 9 (0.446g, 0.573mmol) was dissolved in
THF (25mL) and cooled to 0ꢁC. To this solution was
added 1.0M tetrabutyl ammonium fluoride solution
(0.6mL). After 4.5h satd aq NH4Cl solution (10.0mL)
was added. The reaction mixture was extracted with
EtOAc and the combined extracts were dried over
Na2SO4, filtered, concentrated to dryness, and purified
by chromatography using 1:1 hexane–ethyl acetate as
eluant. Compound 10 was obtained as a syrup
˚
(10.0mL). Powdered 4A molecular sieves (0.1g) were
added and after the mixture was stirred under N2 at
0ꢁC for 45min. N-iodosuccinimide (0.0521g,
0.232mmol) and silver triflate (0.0062g, 0.024mmol)
were added. After being stirred for an additional
10min the reaction mixture was neutralized with Et3N,
diluted with CH2Cl2, and filtered through Celite. The fil-
trate was washed successively with satd aq Na2S2O3 and
H2O. The filtrate was dried over Na2SO4, filtered, and
concentrated to dryness and purified by chromatogra-
phy using 2:1 hexane–ethyl acetate as eluant. Com-
pound 9 was obtained as a syrup (0.0911g, 65.8%).
25
1
(0.254g, 82.1%); ½aꢀ +42.1 (c 0.70, CHCl3); H NMR
D
(300.13MHz, CDCl3): dH, 7.4–7.2 (m, 5H, aromatic),
5.44 (br s, 1H, H-2 Api), 5.21 (br s, 1H, H-1 Api),
4.71 (d, 1H, J1,2 3.6Hz, H-1 Gal), 4.56, 4.49 (2d, 2H,
0
0
JHa,Hb 12.2Hz, OCH2Ph), 4.18, 4.13 (2d, 2H, J3a ,3b
8.5Hz, H-30a, H-30b Api), 4.17 (1H, H-3 Gal), 4.16
(1H, H-4 Gal), 4.14, 3.93 (2d, 2H, J4a,4b 10.5Hz, H-4a,
H-4b Api), 3.96 (1H, H-5 Gal), 3.89, 3.78 (2H, H-6a,
H-6b Gal), 3.66 (dd, 1H J2,3 7.3Hz, H-2 Gal), 3.30 (s,
3H, OCH3), 2.06, 2.03 (2s, 6H, OCOCH3), 1.48, 1.30
(2s, 6H, C(CH3)2); 13C NMR (75.03MHz, CDCl3): dC,
170.2, 169.3 (C@O acetate), 138.1, 128.5, 127.8, 127.7
(aromatic), 109.7 (OC(CH3)2), 106.4 (C-1 Api), 99.3
(C-1 Gal), 85.7 (C-3 Api), 76.8 (C-2 Api), 76.1 (C-2
Gal), 75.4 (C-3 Gal), 74.4 (C-4 Gal), 73.6 (C-30 Api,
OCH2OPh), 69.9 (C-4 Api), 67.3 (C-5 Gal), 62.7 (C-6
Gal), 55.6 (OCH3), 28.4, 26.6 (OC(CH3)2), 21.5, 20.8
(OCOCH3). Anal. Calcd for C26H36O12: C, 57.77; H,
6.71. Found: C, 57.43; H, 6.73.
3.3.4. Table 1, entry 4. A mixture of thioglycoside 7 (a-
anomer, 0.508g, 1.18mmol) and galactose derivative 814
(0.483g, 1.02mmol) was dissolved in CH2Cl2 (10.0mL).
˚
Powdered 4A molecular sieves (1.0g) were added and
after the mixture was stirred under N2 at 0ꢁC for 1h.
N-iodosuccinimide (0.347g, 1.54mmol) and silver tri-
flate (0.108g, 0.420mmol) were added. After being stir-
red for 10min the reaction mixture was neutralized with
Et3N, diluted with CH2Cl2 and filtered through Celite.
The filtrate was washed successively with satd aq
Na2S2O3, H2O, and brine. The filtrate was dried over
Na2SO4, filtered, concentrated to dryness, and purified