3786
J.D.C. Code´e et al. / Tetrahedron 65 (2009) 3780–3788
78.2 (C-30), 99.7 (C-1), 101.0 (C-10), 127.4–128.2 (CHarom), 138.5
(Cq Ph), 167.7 (C]O CO2CH3 or Lev), 169.7 (C]O CO2CH3 or Lev),
171.5 (C]O CO2CH3 or Lev), 206.1 (C]O Lev). 13C GATED NMR
H-30, H-20), 3.72 (m, 4H, C-1–OCH3, H-6b), 3.82 (d, 1H, J¼10 Hz, H-
50), 4.00 (t, 1H, J¼8.8 Hz, H-3), 4.09 (dd, 1H, J¼10.4, 1.6 Hz, H-6a),
4.13 (s, 1H, H-10), 4.40 (t, 1H, J¼10.0 Hz, H-40), 4.45 (d, 1H, J¼11.6 Hz,
CHHPh), 4.57 (d, 1H, J¼3.6 Hz, H-1), 4.68 (d, 1H, J¼12.0 Hz, CHHPh),
4.76–4.89 (m, 5H, 5ꢂCHHPh), 5.02 (d, 1H, Jgem¼10.8 Hz, CHHPh),
7.13–7.38 (m, 20H, 20ꢂHarom). 13C NMR (100 MHz): 17.7 (CH3 BBA),
47.8 (OCH3 BBA), 47.9 (OCH3 BBA), 52.1 (CH3 CO2CH3), 55.0 (C-1–
OCH3), 61.9 (C-6), 64.7 (C-40), 68.3 (CH2Ph), 69.5 (C-30), 70.6 (C-20),
73.3 (CH2Ph), 74.0 (C-50), 74.2 (C-4), 74.6 (CH2Ph), 75.6 (CH2Ph),
77.4 (C-4), 79.7 (C-2), 82.1 (C-3), 97.7 (C-1), 99.6 (Cq BBA), 99.9 (Cq
BBA), 101.8 (C-10), 127.2–128.4 (CHarom), 138.4 (Cq Ph), 138.7 (Cq Ph),
0
0
(100 MHz): 99.7 (JC-1,
¼174 Hz), 101.0 (JC-1 ,
¼161 Hz).
H-1
H-1
HRMS: [MþNa]þ calcd for C48H54O15Na: 893.3355, found
893.3359.
3.10. Methyl (methyl 2,3-di-O-benzyl-4-O-[methyl (2,3-di-O-
benzyl-4-O-levulinoyl-b-D-mannopyranosyluronate)]-b-D-
mannopyranosyluronate) (19)
Disaccharide 19 was obtained from donor 6 (87 mg, 0.15 mmol)
and acceptor 12 (91 mg, 0.225 mmol, 1.5 equiv) according to the
general procedure for glycosylations. Disaccharide 19 was isolated
138.9 (Cq Ph). 13C GATED NMR (100 MHz): 97.7 (JC-1, H-1¼168 Hz),
þ
0
0
100.8 (JC-1 , H-1 ¼156 Hz). HRMS: [MþNa] calcd for C48H58O14Na:
881.3719, found 881.3718.
as an oily residue in 55% yield (72 mg, 0.083 mmol). [
a
]
D
ꢀ41.5 (c
1.7, DCM). IR (neat): 729, 806, 895, 1049, 1103, 1153, 1207, 1265,
1362, 1454, 1497, 1720, 1747, 2885. 1H NMR (400 MHz): 2.15 (s, 3H,
CH3 Lev), 2.50–2.55 (m, 2H, CH2 Lev), 2.66–2.69 (m, 2H, CH2 Lev),
3.44 (dd, 1H, J¼2.8, 9.6 Hz, H-30), 3.53 (s, 3H, CH3 CO2CH3), 3.55 (s,
3H, CH3 CO2CH3), 3.63 (m, 4H, CH3 C-1–OCH3, H-3), 3.68 (d, 1H,
J¼8.0 Hz, H-50), 3.82 (m, 2H, H-2, H-20), 3.90 (d, 1H, J¼8.4 Hz, H-5),
4.38–4.43 (m, 3H, CHHPh, H-1, H-4), 4.50 (d, 1H, J¼12.8 Hz, CHHPh),
4.53 (d, 1H, J¼12.0 Hz, CHHPh), 4.69 (m, 2H, H-10, CHHPh), 4.72–
4.85 (m, 4H, 4ꢂCHHPh), 5.42 (t, 1H, J¼9.6 Hz, H-40), 7.18–7.32 (m,
20H, 20ꢂHarom). 13C NMR (100 MHz): 27.8 (CH2 Lev), 29.8 (CH3 Lev),
37.7 (CH2 Lev), 52.3 (2ꢂCO2CH3), 57.4 (C-1–OCH3), 68.9 (C-4), 71.7
(CH2Ph), 72.0 (CH2Ph), 73.2 (C-50), 73.7 (CH2Ph), 73.8 (C-2 or C-20),
74.2 (C-5), 74.3 (CH2Ph), 74.8 (C-20 or C-20), 73.4 (C-4), 78.4 (C-30),
78.7 (C-3), 102.2 (C-10), 102.8 (C-1), 127.2–128.3 (CHarom), 137.8 (Cq
Ph), 138.3 (Cq Ph), 138.5 (Cq Ph), 138.6 (Cq Ph), 167.7 (C]O CO2CH3
or Lev), 168.7 (C]O CO2CH3 or Lev), 171.5 (C]O CO2CH3 or Lev),
3.12. para-Methoxyphenyl 2-O-benzyl-4,6-benzylidene-4-O-
[methyl (ethyl 2-O-benzyl-3,4-O-[20,30-dimethoxybutan-
20,30-diyl]-
pyranoside (21)
a-D-mannopyranosyluronate)]-b-D-galacto-
Disaccharide 21 was obtained from donor 7 (89 mg, 0.18 mmol)
and acceptor 10 (125 mg, 0.27 mmol, 1.5 equiv) according to the
general procedure for glycosylations. Disaccharide 21 was isolated
as a white amorphous solid in 56% yield (86 mg, 0.10 mmol). [a]
D
þ26.0 (c 0.2, DCM). IR (neat): 733, 826, 887, 999, 1034, 1061, 1080,
1111, 1134, 1180, 1219, 1265, 1369, 1454, 1508, 1751, 2835, 2951. 1H
NMR (400 MHz): 1.34 (s, 6H, 2ꢂCH3 BDA), 3.17 (s, 3H, OCH3 BDA),
3.27 (s, 3H, OCH3 BDA), 3.44 (s, 1H, H-5), 3.66 (s, 3H, OCH3 pMP),
3.75 (m, 4H, H-20, CO2CH3), 3.93 (m, 2H, H-2, H-3), 4.03 (d, 1H,
J¼11.2 Hz, H-6a), 4.22 (d, 1H, J¼2.4 Hz, H-4), 4.27 (d, 1H, J¼8 Hz, H-
30), 4.33–4.42 (m, 3H, H-6b, H-40, H-50), 4.68 (d, 1H, Jgem¼12.4 Hz,
CHHPh), 4.78 (d, 1H, J¼10.0 Hz, CHHPh), 4.89 (m, 2H, H-1, CHHPh),
4.95 (d, 1H, J¼12.4 Hz, CHHPh), 5.10 (s, 1H, H-10), 5.43 (s, 1H, CHPh
benzylidene), 6.81 (d, 2H, J¼8.8 Hz, Harom pMP), 7.05 (d, 2H,
J¼8.8 Hz, 2Harom pMP), 7.23–7.38 (m, 15H, 15ꢂHarom). 13C NMR
(100 MHz): 17.8 (CH3 BDA), 17.8 (CH3 BDA), 47.8 (OCH3 BDA), 52.1
(OCH3 CO2CH3), 55.6 (OCH3 pMP), 64.9 (C-50), 66.2 (C-5), 68.4 (C-
30), 68.4 (C-6), 70.6 (C-40), 70.9 (C-4), 73.2 (CH2Ph), 73.9 (C-3), 75.0
(CH2Ph), 76.0 (C-2), 95.3 (C-10), 99.7 (Cq BDA), 100.0 (Cq BDA), 100.9
(CHPh benzylidene), 102.8 (C-1), 114.4 (CHarom pMP), 118.8 (CHarom
pMP), 126.3–129.0 (CHarom), 137.6 (Cq Ph), 137.8 (Cq Ph), 138.6 (Cq
Ph),151.6 (Cq pMP),155.3 (Cq pMP),169.3 (C]O CO2CH3). 13C GATED
206.2 (C]O Lev). 13C GATED NMR (100 MHz): 102.2 (JC-1 ,
¼
0
0
H-1
154 Hz), 102.9 (JC-1,
C48H54O15Na: 893.3355, found 893.3360.
¼156 Hz). HRMS: [MþNa]þ calcd for
H-1
3.11. Methyl 2,3,4-tri-O-benzyl-6-O-[methyl (ethyl 2-O-
benzyl-3,4-O-[20,30-dimethoxybutan-20,30-diyl]-
a/b-D-
mannopyranosyluronate)]-a-D-glucopyranoside (20)
Mannuronic acid 7 (135 mg, 0.27 mmol) was condensed with
glucoside 9 (186 mg, 0.40 mmol, 1.5 equiv) following the general
procedure for glycosylations. Column chromatography (Tol/EtOAc
0
0
0
1/0 to 7/1) gave 20
a
and 20
b
as clear oils (129 mg, 0.15 mmol, 56%).
NMR (100 MHz): 95.2 (JC-1 ,
¼171 Hz, C-1 ), 102.8 (JC-1,
¼
H-1
H-1
a
-Isomer: [
a
]
þ99.4 (c 1.8, DCM). IR (neat): 733, 822, 849, 887,
164 Hz, C-1). HRMS: [MþNa]þ calcd for C47H54O15Na: 881.3355,
D
1026, 1111, 1134, 1207, 1265, 1377, 1454, 1497, 1751, 2835, 2924. 1H
NMR (400 MHz): 1.34 (s, 3H, CH3 BDA), 1.38 (s, 3H, CH3 BDA), 3.20
(s, 3H, OCH3 BDA), 3.25 (s, 3H, OCH3 BDA), 3.33 (s, 3H, CO2CH3), 3.38
(t, 1H, J¼9.2 Hz, H-4), 3.45 (dd, 1H, J¼9.6 , 3.6 Hz, H-2), 3.68–3.71
(m, 6H, H-6a, H-20, H-5, CH3 C-1–OCH3), 3.78 (m, 1H, H-6b), 3.97 (t,
1H, J¼9.6 Hz, H-3), 4.05 (dd, 1H, J¼2.8, 10.1 Hz, H-30), 4.24 (d, 1H,
J¼10.4 Hz, H-50), 4.40 (t,1H, J¼10.4 Hz, H-40), 4.54–4.58 (m, 2H, H-1,
CHHPh), 4.65–4.68 (m, 2H, 2ꢂCHHPh), 4.75–4.82 (m, 2H,
2ꢂCHHPh), 4.89–4.91 (m, 2H, 2ꢂCHHPh), 4.93–4.99 (m, 2H, H-10,
CHHPh), 7.13–7.67 (m, 20H, 20ꢂHarom). 13C NMR (100 MHz): 17.6
(CH3 BDA), 17.7 (CH3 BDA), 47.8 (OCH3 BDA), 52.1 (CO2CH3), 54.9 (C-
1–OCH3), 64.9 (C-40), 66.2 (C-6), 68.4 (C-30), 69.8 (C-20), 70.6 (C-50),
73.0 (CH2Ph), 73.2 (CH2Ph), 75.0 (C-5), 75.1 (CH2Ph), 75.8 (CH2Ph),
77.9 (C-4), 80.0 (C-20), 82.0 (C-3), 97.7 (C-1), 99.6 (Cq BDA), 100.0 (Cq
BDA), 100.2 (C-10), 124.7–131.0 (CHarom), 138.0 (Cq Ph), 138.1 (Cq Ph),
found 881.3358.
3.13. Methyl 2,3-di-O-benzyl-4-O-[methyl (ethyl 2-O-benzyl-
3,4-O-[20,30-dimethoxybutan-20,30-diyl]-
a-
D-manno-
pyranosyluronate)]-a-D-mannopyranosyluronate (22)
Mannuronic acid 7 (117 mg, 0.23 mmol) was condensed with
mannuronic acid 11 (139 mg, 0.35 mmol,1.5 equiv) according to the
general procedure for glycosylations. Column chromatography gave
a-linked disaccharide 22 as a clear oil in 24% yield (44 mg,
0.055 mmol). [
a
]
þ123.8 (c 0.8, DCM). IR (neat): 733, 910, 1053,
D
1096, 1207, 1242, 1265, 1362, 1454, 1497, 1720, 1747, 2870, 2924. 1H
NMR (400 MHz): 1.25 (s, 3H, CH3 BDA), 1.28 (s, 3H, CH3 BDA), 3.21
(s, 3H, OCH3 BDA), 3.24 (s, 3H, OCH3 BDA), 3.41 (s, 3H, OCH3), 3.58 (t,
1H, J¼2.4 Hz, H-20), 3.66 (t, 1H, J¼3.2 Hz, H-2), 3.75 (m, 7H, H-3,
2ꢂCO2CH3), 3.95 (dd, 1H, J¼2.4, 10 Hz, H-30), 4.12 (d, 1H, J¼9.6 Hz,
H-5), 4.17 (d, 1H, J¼8.4 Hz, H-50), 4.33 (t, 1H, J¼10.4 Hz, H-4), 4.36–
4.43 (m, 3H, H-40, 2ꢂCHHPh), 4.61 (d, 1H, J¼12.4 Hz, CHHPh), 4.67
(m, 2H, 2ꢂCHHPh), 4.86 (d, 1H, J¼2.8 Hz, H-1), 5.24 (s, 1H, H-10),
7.19–7.31 (m, 15H, 15ꢂHarom). 13C NMR (100 MHz): 17.7 (CH3 BDA),
17.8 (CH3 BDA), 47.7 (OCH3 BDA), 47.9 (OCH3 BDA), 52.1 (CH3
CO2CH3), 52.6 (CH3 CO2CH3), 55.7 (C-1–OCH3), 64.9 (C-40), 68.0
138.6 (Cq Ph), 169.1 (C]O CO2CH3). 13C GATED NMR (100 MHz):
þ
0
0
97.6 (JC-1, H-1¼167 Hz), 100.12 (JC-1 , H-1 ¼170 Hz). HRMS: [MþNa]
calcd for C48H58O14Na: 881.3719, found 881.3719. Isomer: [
b
a
]
D
þ77.2 (c 0.8, DCM). IR: 733, 799, 849, 895, 1038, 1111, 1134, 1265,
1362, 1454, 1497, 1751, 2928. 1H NMR (400 MHz): 1.27 (s, 3H, CH3
BDA), 1.32 (s, 3H, CH3 BDA), 3.26 (s, 6H, 2ꢂOCH3 BDA), 3.32 (s, 3H,
CH3 CO2CH3), 3.37–3.45 (m, 2H, H-4, H-5), 3.50–3.59 (m, 3H, H-2,