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N. Basu et al. / Carbohydrate Research 346 (2011) 534–539
4.3. Procedure for benzylidenation and acetylation of
disaccharides
4.4.7. 4-Methoxyphenyl 2,3-di-O-acetyl-4,6-O-benzylidene-a-D-
glucopyranosyl-(1?4)-2,4,6-tri-O-acetyl-b-D-glucopyranoside
(22f)
To a solution of unprotected disaccharides (0.2 mmol) and
benzaldehyde dimethylacetal (0.3 mmol) in dry CH3CN (3 mL)
and 4 Å MS, anhyd FeCl3 (0.24 mmol) was added, and the mixture
was stirred at room temperature for 2–2.5 h. After completion of
reaction (indicated by TLC), dry pyridine (1.5 mL), Ac2O (2 mmol),
and DMAP (10 mol %) were added. After complete acetylation,
the reaction mixture was concentrated and diluted with CH2Cl2.
It was washed with cold water (2 ꢀ 5 mL). The organic layer was
dried over dry Na2SO4, and then concentrated under reduced pres-
sure. It was purified by column chromatography on silica gel. The
Yield 67% (two steps); white crystals (EtOH); mp 182–184 °C;
½ ꢂ
a 2D5
+24.5 (c 0.49, CHCl3); 1H NMR (CDCl3, 300 MHz): d 7.44–
7.40 (m, 2H), 7.36–7.33 (m, 3H), 6.95–6.90 (m, 2H), 6.84–6.80
(m, 2H), 5.50–5.43 (m, 2H), 5.38 (d, 1H, J = 4.1 Hz), 5.31 (t, 1H,
J = 8.8 Hz), 5.06 (t, 1H, J = 7.7 Hz), 4.97 (d, 1H, J = 7.7 Hz), 4.89
(dd, 1H, J = 4.2, 10.2 Hz), 4.54 (dd, 1H, J = 2.7, 12.1 Hz), 4.32–4.24
(m, 2H), 4.08 (t, 1H, J = 9.2 Hz), 3.91–3.80 (m, 2H), 3.77 (s, 3H),
3.74 (s, 1H), 3.70–3.60 (m, 1H), 2.08, 2.06, 2.05, 2.04, 2.01 (5 ꢀ s,
15H), 13C NMR (CDCl3, 75 MHz): d 170.9, 170.4, 170.3, 169.9,
155.9, 150.9, 136.8, 129.2, 128.3, 126.3, 119.0, 114.7, 101.7, 99.9,
96.7, 78.9, 77.4, 75.6, 73.0, 72.4, 72.3, 71.0, 68.6, 63.9, 62.7, 55.8,
21.1, 20.9, 20.8, 20.7; HRESIMS: calcd for C36H42O17Na+ m/z
769.2320; found, m/z 769.2324.
NMR spectra of known compounds (18f,25 19f,26 20f24 and 21f24
)
matched those reported.
4.4. Characteristic data of selected products
4.4.8. 20-Azidoethyl 2,3-di-O-acetyl-4,6-O-benzylidene-
a-D-
4.4.1. 4-Chlorophenyl 4,6-O-benzylidene-1-thio-b-
D-gluco-
glucopyranosyl-(1?4)-2,4,6-tri-O-acetyl-b-D-glucopyranoside
pyranoside (9b)
(23f)
Yield 88%; white crystals (EtOH); mp 156–158 °C; ½a D25
ꢂ
ꢃ41.6 (c
Yield 69% (two steps); white crystals (EtOH); mp 186–188 °C;
1.59, CHCl3); 1H NMR (CDCl3, 300 MHz): d 7.48–7.45 (m, 4H), 7.37–
7.29 (m, 5H), 5.51 (s, 1H), 4.57 (d, 1H, J = 9.7 Hz), 4.38–4.33 (m,
1H), 3.83–3.71 (m, 2H), 3.49–3.39 (m, 3H), 3.15 (br s, 1H), 2.94
(br s, 1H), 13C NMR (CDCl3, 75 MHz): d 136.9, 135.0, 134.7, 129.8,
129.5, 129.4, 128.5, 126.4, 102.1, 88.4, 80.3, 74.7, 72.7, 70.7, 68.6;
HRESIMS: calcd for C19H19ClO5SNa+ m/z 417.0540; found, m/z
417.0544.
½ ꢂ
a 2D5
+2.0 (c 2.25, CHCl3); 1H NMR (CDCl3, 300 MHz): d 7.42–7.34
(m, 5H), 5.48–5.42 (m, 2H), 5.36 (d, 1H, J = 3.8 Hz), 5.26 (t, 1H,
J = 9.0 Hz), 4.90–4.82 (m, 2H), 4.61–4.57 (m, 2H), 4.26–4.22 (m,
2H), 4.06–3.98 (m, 2H), 3.89–3.81 (m, 1H), 3.76–3.59 (m, 4H),
3.51–3.44 (m, 1H), 3.26–3.22 (m,1H), 2.11, 2.05, 2.04, 2.02, 2.01
(5 ꢀ s, 15H), 13C NMR (CDCl3, 75 MHz): d 170.8, 170.3, 170.2,
169.8, 169.7, 136.7, 129.1, 128.2, 126.2, 101.6, 100.2, 96.5, 78.8,
75.4, 72.6, 72.3, 72.0, 70.8, 69.2, 68.7, 68.5, 63.7, 62.3, 50.5, 20.9,
20.8 (2), 20.7, 20.6; HRESIMS: calcd for C31H39N3O16Na+ m/z
732.2228; found, m/z 732.2229.
4.4.2. 20-Azidoethyl 4,6-O-benzylidene-b-
D-glucopyranoside
(13b)19
Yield 79%; white crystals (EtOH); mp 90–92 °C; ½a D25
ꢃ57.4 (c
ꢂ
0.58, CHCl3); 1H NMR (CDCl3, 300 MHz): d 7.50–7.48 (m, 2H),
7.37–7.36 (m, 3H), 5.51 (s, 1H), 4.41 (d, 1H, J = 7.7 Hz), 4.32 (dd,
1H, J = 4.8, 10.4 Hz), 4.05–4.00 (m, 1H), 3.82–3.71 (m, 3H), 3.56–
3.48 (m, 3H), 3.44–3.38 (m, 4H).
Acknowledgments
The authors are grateful to CSIR, New Delhi, India for providing
a fellowship (JRF) to N.B. and for funding the project (No. 01/2382/
10/EMR-II) to R.G. Support from FIST-DST, India to the Department
of Chemistry, Jadavpur University, Kolkata is also acknowledged.
4.4.3. 4-Bromophenyl 4,6-O-benzylidene-b-D-glucopyranoside
(16b)
Yield 83%; white crystals (EtOH); mp 182–184 °C; ½a D25
ꢃ38.8 (c
ꢂ
References
0.89, CHCl3); 1H NMR (CDCl3, 300 MHz): d 7.51–7.48 (m, 2H), 7.42–
7.36 (m, 5H), 6.95–6.92 (d, 2H, J = 8.9 Hz), 5.53 (s, 1H), 4.95 (d, 1H,
J = 7.6 Hz), 4.35 (dd, 1H, J = 4.7, 10.6 Hz), 3.91–3.74 (m, 3H), 3.64–
3.50 (m, 2H), 3.16 (s, 1H), 3.07 (d, 1H, J = 1.9 Hz), 13C NMR (75 MHz,
CDCl3): d 155.9, 136.8, 132.5, 129.4, 128.4, 126.3, 118.8, 115.8,
102.0, 101.2, 80.2, 74.2, 73.2, 68.5, 66.6; HRESIMS: calcd for
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4.4.4. Methyl 2,3-di-O-acetyl-4,6-O-benzylidene-b-
D
-galacto-
pyranosyl-(1?4)-2,4,6-tri-O-acetyl-1-thio-b-
D-glucopyranoside
(19f)26
Yield 72%; white crystals (EtOH); mp 220–222 °C; ½a D25
ꢂ
+36.5 (c
0.1.46, CHCl3).
4.4.5. Phenyl 2,3-di-O-acetyl-4,6-O-benzylidene-b-
D
-glucopyran-
osyl-(1?4)-2,4,6-tri-O-acetyl-1-thio-b-D
-glucopyranoside (20f)24
Yield 61%; white crystals (EtOH); mp 264–266 °C, lit.24 mp
267 0.1 °C; ½a 2D5
ꢂ
ꢃ42.5 (c 0.50, CHCl3), lit.24
[a
]
D
ꢃ45.3 (c 0.83,
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galactopyranosyl-(1?4)-2,4,6-tri-O-acetyl-1-thio-b-D-
glucopyranoside (21f)24
Yield 84%; white crystals (EtOH); mp 254–256 °C, lit.24 mp
255 0.25 °C; ½a 2D5
ꢂ
+23 (c 0.50, CHCl3), lit.24
[a
]
D
+24.4 (c 0.70,
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