E. Bedini et al. / Carbohydrate Research 349 (2012) 24–32
31
4.14. Allyl (3,4,6-tri-O-acetyl-2-O-methoxycarbonyl-b-
galactopyranosyl)-(1?3)-(2-azido-4,6-O-benzylidene-2-deoxy-
-galactopyranosyl)-(1?3)-2-azido-4,6-O-benzylidene-2-
deoxy-b- -galactopyranoside (17)
D
-
3.99 (m, 3H, H-2A, H-6bA, H-6bB), 3.89 (t, 1H, J5,6 6.6 Hz, H-5C),
3.84 (dd, 1H, J3,2 11.2 Hz, J3,2 3.1 Hz, H-3B), 3.69 (s, 3H, CO2CH3),
3.65 (br s, 1H, H-5B), 3.43 (br s, 1H, H-5A), 2.12 (s, 3H, OCOCH3),
2.01 (s, 3H, OCOCH3), 1.96 (s, 3H, OCOCH3), 1.94 (s, 3H, NCOCH3),
1.45 (s, 3H, NCOCH3); 13C NMR (125 MHz, CDCl3) d 170.3–170.0
(5CH3CO), 154.5 (CO2CH3), 137.6, 137.5 (2Cipso benzylidene),
133.9 (OCH2CH@CH2), 129.5–126.1 (C-Ar), 117.7 (OCH2CH@CH2),
102.2 (C-1C), 101.3, 100.6, 99.0 (C-1A, 2CH benzylidene), 95.4 (C-
1B), 75.9, 73.9, 72.7, 71.4, 70.6, 69.3, 69.1, 67.0, 66.2, 63.6, 61.1,
55.1, 52.2, 47.4 (C-2C, C-3A, C-3B, C-3C, C-4A, C-4B, C-4C, C-5A, C-
5B, C-5C, C-6A, C-6B, C-6C, OCH2CH@CH2), 55.1, 52.2, 47.4 (C-2A, C-
2B, CO2CH3), 20.7–20.5 (5COCH3). MALDI TOF-MS for C47H58N2O21
(m/z): Mr (calcd) 986.35, Mr (found) 1009.15 (M+Na)+. Anal. Calcd:
C, 57.20; H, 5.92; N, 2.84. Found: C, 56.89; H, 5.71; N, 2.77.
a-D
D
A mixture of 9 (126.4 mg, 0.207 mmol) and 14 (210.5 mg,
0.415 mmol) was coevaporated thrice with toluene (3 mL). The
residue was dried and then mixed with freshly activated AW-300
4 Å molecular sieves, suspended under argon atmosphere in CH2Cl2
(4.4 mL). The mixture was stirred at 0 °C for 15 min. A 3.2% v/v
TMSOTf solution in CH2Cl2 (225 lL, 41.5 lmol) was then added.
The mixture was stirred for 2 h at 0 °C, then some drops of Et3N
were added and the mixture was filtered over a Celite pad and con-
centrated. The residue was subjected to column chromatography
(10:1–3:1 v/v toluene/ethyl acetate) to give 17 (146.4 mg, 74%)
as a colourless oil. [
a
]
D
+81.8 (c 1.5, CH2Cl2); 1H NMR (500 MHz,
4.16. Allyl (3,4,6-tri-O-acetyl-2-O-methoxycarbonyl-b-
D-
CDCl3): d 7.57–7.36 (m, 10H, H-Ar), 5.96 (m, 1H, OCH2CH@CH2),
5.60 (s, 2H, 2CH benzylidene), 5.43 (d, 1H, J4,3 3.0 Hz, H-4C), 5.35
(dd, 1H, Jvic 17.0 Hz, Jgem 2.0 Hz, trans OCH2CH@CHH), 5.29 (d,
1H, J1,2 4.0 Hz, H-1B), 5.24 (dd, 1H, Jvic 10.5 Hz, Jgem 2.0 Hz, cis
OCH2CH@CHH), 5.06 (m, 2H, H-2C, H-3C), 4.82 (d, 1H, J1,2 7.5 Hz,
H-1C), 4.47 (dd, 1H, Jgem 13.0 Hz, Jvic 3.5 Hz, OCHHCH@CH2), 4.45
(d, 1H, J4,3 3.0 Hz, H-4B), 4.36 (m, 2H, H-1A, H-5C), 4.31 (d, 1H, J4,3
3.5 Hz, H-4A), 4.28 (dd, 1H, Jgem 12.5 Hz, J6a,5 1.0 Hz, H-6aB), 4.24
(dd, 1H, J3,2 10.5 Hz, J3,4 3.0 Hz, H-3B), 4.14 (m, 5H, H-6aA, H-6aC,
H-6bB, H-6bC, OCHHCH@CH2), 3.95 (m, 4H, H-2A, H-2B, H-5B, H-
6bA), 3.72 (s, 3H, CO2CH3), 3.69 (dd, 1H, J3,2 10.5 Hz, J3,4 3.5 Hz,
H-3A), 3.40 (br s, 1H, H-5A), 2.15 (s, 3H, COCH3), 2.03 (s, 3H,
COCH3), 1.99 (s, 3H, COCH3); 13C NMR (125 MHz, CDCl3) d 170.3,
170.2, 169.9 (3CH3CO), 154.8 (CO2CH3), 137.6, 137.3 (2Cipso benzyl-
idene), 133.4 (OCH2CH@CH2), 129.0–125.3 (C-Ar), 117.9
(OCH2CH@CH2), 102.0 (C-1C), 100.9, 100.6, 100.5 (C-1A, 2CH ben-
zylidene), 94.6 (C-1B), 77.2, 75.6, 75.1, 74.0, 72.6, 70.9, 70.8, 70.4,
70.1, 70.0, 69.1, 67.0, 66.4, 63.7, 61.4, 58.3, 55.1 (C-2A, C-2B, C-2C,
C-3A, C-3B, C-3C, C-4A, C-4B, C-4C, C-5A, C-5B, C-5C, C-6A, C-6B, C-
6C, OCH2CH@CH2, CO2CH3), 21.4, 20.6, 20.5 (3COCH3). MALDI
TOF-MS for C43H50N6O19 (m/z): Mr (calcd) 954.31, Mr (found)
977.58 (M+Na)+. Anal. Calcd: C, 54.09; H, 5.28; N, 8.80. Found: C,
53.78; H, 5.12; N, 8.60.
galactopyranosyl)-(1?3)-(2-acetamido-2-deoxy-
galactopyranosyl)-(1?3)-2-acetamido-2-deoxy-b-D-
galactopyranoside (19)
a-D-
Compound 18 (25.6 mg, 26.0 lmol) was dissolved in 90% AcOH
(1.25 mL). The solution was stirred at 50 °C for 8 h, after that it was
concentrated. The residue was subjected to column chromatogra-
phy (93:7–85:15 v/v CH2Cl2/MeOH) to give 19 (15.6 mg, 74%) as
a white foam. [a]
D +62 (c 0.9, CH3OH); 1H NMR (600 MHz, CD3OD):
d 5.91 (m, 1H, OCH2CH@CH2), 5.40 (d, 1H, J1,2 3.5 Hz, H-1B), 5.27
(dd, 1H, Jvic 17.3 Hz, Jgem 1.7 Hz, trans OCH2CH@CHH), 5.15 (dd,
1H, Jvic 10.5 Hz, Jgem 1.6 Hz, cis OCH2CH@CHH), 5.11 (dd, 1H, J3,2
10.4 Hz, J3,4 3.5 Hz, H-3C), 4.92 (m, 2H, H-2C, H-4C), 4.77 (d, 1H,
J1,2 8.0 Hz, H-1C), 4.47 (dd, 1H, J2,3 11.1 Hz, J2,1 3.5 Hz, H-2B), 4.41
(d, 1H, J1,2 8.4 Hz, H-1A), 4.34 (dd, 1H, Jgem 13.3 Hz, Jvic 4.9 Hz,
OCHHCH@CH2), 4.18–4.08 (m, 6H, H-4A, H-6aB, H-6aC, H-6bB, H-
6bC, OCHHCH@CH2), 3.97 (d, 1H, J4,3 2.9 Hz, H-4B), 3.81–3.69 (m,
9H, H-2A, H-3B, H-5B, H-5C, H-6aA, H-6bA, CO2CH3), 3.65 (dd, 1H,
J3,2 10.9 Hz, J3,4 3.1 Hz, H-3A), 3.43 (t, 1H, J5,6 5.9 Hz, H-5A), 2.12
(s, 3H, COCH3), 2.02 (s, 3H, COCH3), 2.01 (s, 3H, COCH3), 1.97 (s,
3H, COCH3), 1.95 (s, 3H, COCH3); 13C NMR (50 MHz, CD3OD) d
174.8, 174.3, 172.9, 172.7, 172.2 (5CH3CO), 157.5 (CO2CH3), 136.4
(OCH2CH@CH2), 118.1 (OCH2CH@CH2), 104.7, 102.9 (C-1A, C-1C),
96.8 (C-1B), 81.0, 78.5, 77.4, 75.1, 73.6, 73.1, 72.8, 71.7, 71.6, 71.0,
69.9, 66.3, 63.5, 63.3 (C-2C, C-3A, C-3B, C-3C, C-4A, C-4B, C-4C, C-
5A, C-5B, C-5C, C-6A, C-6B, C-6C, OCH2CH@CH2), 56.8, 52.8, 50.4 (C-
2A, C-2B, CO2CH3), 24.2, 23.8 (2 NHCOCH3), 21.6, 21.4, 21.3 (3
OCOCH3). MALDI TOF-MS for C33H50N2O21 (m/z): Mr (calcd)
810.29, Mr (found) 833.03 (M+Na)+. Anal. Calcd: C, 48.89; H,
6.22; N, 3.46. Found: C, 48.63; H, 6.40; N, 3.31.
4.15. Allyl (3,4,6-tri-O-acetyl-2-O-methoxycarbonyl-b-
galactopyranosyl)-(1?3)-(2-acetamido-4,6-O-benzylidene-2-
deoxy- -galactopyranosyl)-(1?3)-2-acetamido-4,6-O-
benzylidene-2-deoxy-b- -galactopyranoside (18)
D-
a-D
D
A solution of 17 (141.7 mg, 0.149 mmol) in THF (4.4 mL) was di-
luted with Ac2O (2.9 mL) and AcOH (1.5 mL) and then treated with
Zn/Cu (405 mg). After 5 h stirring at rt a second aliquot of Zn/Cu
(210 mg) was added and the mixture was stirred overnight. It
was then filtered over a Celite pad and concentrated. The residue
was dissolved in 1:1 v/v CH2Cl2/MeOH (8.0 mL) and then treated
4.17. Allyl b-D-galactopyranosyl-(1?3)-(2-acetamido-2-deoxy-
a-
D-galactopyranosyl)-(1?3)-2-acetamido-2-deoxy-b-D-
galactopyranoside (20)
with Ac2O (800
l
L). The solution was stirred at rt for 6 h, after that
A solution of 19 (13.9 mg, 17.2
ted with a 0.55 M methanolic solution of NaOMe (100
l
mol) in MeOH (400
l
l
L) was trea-
L). After 5 h
volatiles were removed. The residue was subjected to column
chromatography (98:2–95:5 v/v CH2Cl2/MeOH) to afford 18
stirring at room temperature, water (1 mL) was added and the solu-
tion was neutralized with Amberlyst-15 (H+ form). After filtration,
volatiles removal and freeze-drying, pure 20 (10.1 mg, 94%) was ob-
(83.5 mg, 57%) as white amorphous crystals. [
a]
+85.5 (c 1.5,
D
CH2Cl2); 1H NMR (600 MHz, CDCl3): d 7.54–7.37 (m, 10H, H-Ar),
5.96 (d, 1H, JH,NH 8.3 Hz, NHA), 5.92 (d, 1H, JH,NH 9.3 Hz, NHB),
5.89 (m, 1H, OCH2CH@CH2), 5.54 (s, 1H, CH benzylidene), 5.45 (s,
1H, CH benzylidene), 5.38 (d, 1H, J4,3 2.0 Hz, H-4C), 5.28 (dd, 1H, Jvic
17.2 Hz, Jgem 1.5 Hz, trans OCH2CH@CHH), 5.20 (dd, 1H, Jvic 10.4 Hz,
Jgem 1.5 Hz, cis OCH2CH@CHH), 5.09 (d, 1H, J1,2 3.5 Hz, H-1B), 4.95
(m, 2H, H-2C, H-3C), 4.71 (d, 1H, J1,2 8.3 Hz, H-1A), 4.64 (d, 1H, J1,2
7.6 Hz, H-1C), 4.61 (dt, 1H, JH,NH = J2,3 9.3 Hz, J2,1 3.5 Hz, H-2B),
4.37 (dd, 1H, Jgem 13.0 Hz, J6a,5 5.1 Hz, H-6aC), 4.26 (d, 1H, J4,3
2.8 Hz, H-4B), 4.21 (d, 1H, Jgem 12.5 Hz, H-6aB), 4.14 (m, 4H, H-3A,
H-4A, H-6aA, OCHHCH@CH2), 4.08 (m, 2H, H-6bC, OCHHCH@CH2),
tained as a white fluffy solid. [
a
]
D
+13 (c 0.6, H2O); 1H NMR
(500 MHz, D2O): d 5.92 (m, 1H, OCH2CH@CH2), 5.33 (d, 1H, Jvic
17.0 Hz, trans OCH2CH@CHH), 5.27 (d, 1H, Jvic 11.0 Hz, cis
OCH2CH@CHH), 5.07 (br s, 1H, J1,2 3.5 Hz, H-1B), 4.58 (d, 1H, J1,2
8.5 Hz, H-1A), 4.44 (d, 1H, J1,2 8.0 Hz, H-1C), 4.38 (m, 2H, H-2B,
OCHHCH@CH2), 4.25 (d, 1H, J4,3 2.0 Hz, H-4B), 4.20 (dd, 1H, Jgem
13.0 Hz, Jvic 6.5 Hz, OCHHCH@CH2), 4.13 (d, 1H, J4,3 3.0 Hz, H-4A),
4.08 (dd, 1H, J2,3 11.0 Hz, J2,1 8.5 Hz, H-2A), 3.91 (d, 1H, J4,3 3.0 Hz,
H-4C), 3.86–3.74 (m, 9H, H-3A, H-3B, H-5B, H-6aA, H-6aB, H-6aC, H-
6bA, H-6bB, H-6bC), 3.65 (m, 3H, H-3C, H-5A, H-5C), 3.51 (dd, 1H, J2,3