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C. Liu et al. / Carbohydrate Research 342 (2007) 2818–2825
EtOAc) to give 4 (477 mg, 85%) as a colorless oil. Rf
0.24 (4:1 hexane–EtOAc); [a]D +49.2 (c 0.8, CHCl3);
1H NMR (500 MHz, CDCl3, dH) 7.40–7.25 (m, 15H,
Ar), 7.01–6.98 (m, 2H, Ar), 6.81–6.77 (m, 2H, Ar),
5.54 (d, 1H, J1,2 = 1.0 Hz, H-1), 4.88 (d, 1H,
J = 11.1 Hz, PhCH2), 4.82 (d, 1H, J = 11.7 Hz, PhCH2),
4.66 (d, 1H, J = 11.7 Hz, PhCH2), 4.65 (d, 1H,
J = 11.1 Hz, PhCH2), 4.57 (d, 1H, J = 11.1 Hz, PhCH2),
4.48 (d, 1H, J = 11.1 Hz, PhCH2), 4.19 (ddd, 1H,
J2,3 = J3,4 = 3.8 Hz, J3,3-OH = 9.2 Hz, H-3), 3.94 (dd,
1H, J1,2 = 1.0 Hz, J2,3 = 3.8 Hz, H-2), 3.91–3.88 (m,
1H, H-5), 3.86–3.80 (m, 2H, H-4, H-6a), 3.77 (s, 3H,
OCH3), 3.71 (dd, 1H, J5,6b = 1.8 Hz, J6a,6b = 11.0 Hz,
H-6b), 2.38 (d, 1H, J3,3-OH = 9.2 Hz, 3-OH); 13C
NMR (125 MHz, CDCl3, dC) 155.0 (Ar), 150.3 (Ar),
138.4 (Ar), 138.3 (Ar), 137.6 (Ar), 128.6 (Ar), 128.4
(Ar · 2), 128.3 (Ar · 2), 128.1 (Ar · 2), 127.9 (Ar · 4),
127.7 (Ar · 3), 127.5 (Ar), 117.8 (Ar · 2), 114.6
(Ar · 2), 96.1 (C-1), 78.2 (C-2), 76.5 (C-4), 74.8
(PhCH2), 73.3 (PhCH2), 73.0 (PhCH2), 71.7 (C-3), 71.5
(C-5), 69.0 (C-6), 55.7 (OCH3). ESIMS m/z: calcd for
[C34H36O7]Na+, 579.2353; found, 579.2349.
(EtOAc) showed that all starting material had been
consumed and was converted to a spot, believed to
correspond to the 2,3:4,6-di-O-isopropylidene derivative
of 7. The mixture was then concentrated, and the result-
ing residue was treated with 25% aq HOAc (12 mL), and
stirred for 14 h. At that time, a mixture of mono- and
diisopropylidene derivatives was observed by TLC,
and the reaction was quenched by the addition of
Et3N. After the concentration of the solution, the crude
product was purified by chromatography (gradient
elution hexane!EtOAc) to give 8 (2.25 g, 61%) as a
solid. Rf 0.22 (1:1 hexane–EtOAc); [a]D +67.9 (c 0.5,
CHCl3); 1H NMR (500 MHz, CDCl3, dH) 7.00–6.97
(m, 2H, Ar), 6.85–6.82 (m, 2H, Ar), 5.67 (s, 1H, H-1)
4.38 (d, 1H, J2,3 = 5.6 Hz, H-2) 4.31 (dd, 1H,
J2,3 = 5.6 Hz, J3,4 = 6.2 Hz, H-3), 3.84–3.76 (m, 7H,
OCH3, H-4, H-5, H-6a, H-6b), 2.80 (d, 1H, J4,4-OH
3.9 Hz, 4-OH), 2.01 (dd, 1H, J6a,6-OH = J6b,6-OH
=
=
1.9 Hz, 6-OH), 1.57 (s, 3H, (CH3)2C), 1.41 (s, 3H,
(CH3)2C); 13C NMR (125 MHz, CDCl3, dC) 155.1
(Ar), 149.7 (Ar), 117.7 (Ar · 2), 114.6 (Ar · 2), 109.8
((CH3)2C), 96.4 (C-1), 78.3 (C-3), 75.5 (C-2), 70.2
(C-5), 69.4 (C-4), 62.1 (C-6), 55.5 (OCH3), 27.9
((CH3)2C), 26.1 ((CH3)2C). ESIMS m/z: calcd for
[C16H22O7]Na+, 349.1258; found, 349.1256.
1.5. 8-Azidooctyl 2-acetamido-2-deoxy-b-D-glucopyran-
oside (6)
To a solution of oxazoline 5 (245 mg, 1 mmol) in a
mixture of CH2Cl2 (1 mL) and 8-azidooctanol (0.5 mL)
anhyd p-TsOH (142 mg) was added. The mixture was
stirred at room temperature for 5 h and then quenched
by the addition basic ion-exchange resin. After gravity
filtration of the mixture, the filtrate was concentrated,
and the crude product was purified by chromatography
(10:1 CH2Cl2–CH3OH) to afford 6 (265 mg, 67%) as
a white solid. Rf 0.82 (5:1 CH2Cl2–CH3OH); [a]D
1.7. p-Methoxyphenyl 4,6-di-O-benzyl-2,3-O-isopropyl-
idene-a-D-mannopyranoside (9)
Diol 8 (1.92 g, 5.88 mmol) was dissolved in DMF
(40 mL), and the solution was cooled to 0 ꢁC. Sodium
hydride (60% in oil, 688 mg, 16.5 mmol) was added,
and the mixture was stirred for 20 min, after which time
BnBr (1.7 mL, 14.3 mmol) was added. The solution was
stirred for 16 h and warmed to room temperature. The
reaction mixture was quenched by the addition of
CH3OH and partitioned between H2O and CH2Cl2.
The organic phase was washed with brine, dried
(Na2SO4), and concentrated, and the resulting crude
product was purified by chromatography (5:1 hexane–
EtOAc) to give 9 (2.94 g, 99%) as a white solid. Rf
0.50 (4:1 hexane–EtOAc); [a]D +78.8 (c 0.7, CHCl3);
1H NMR (500 MHz, CDCl3, dH) 7.33–7.24 (m, 10H,
Ar), 7.06–7.02 (m, 2H, Ar), 6.80–6.78 (m, 2H, Ar),
5.67 (d, 1H, J1,2 = 0.9 Hz, H-1), 4.90 (d, 1H,
J = 11.5 Hz, PhCH2), 4.59 (d, 1H, J = 11.5 Hz, PhCH2),
4.57 (d, 1H, J = 12.0 Hz, PhCH2), 4.48 (dd, 1H,
J2,3 = J3,4 = 5.8 Hz, H-3), 4.45 (d, 1H, J = 12.0 Hz,
PhCH2), 4.37 (dd, 1H, J1,2 = 0.9 Hz, J2,3 = 5.8 Hz,
H-2), 3.97–3.93 (m, 1H, H-5), 3.75 (s, 3H, OCH3),
3.71–3.67 (m, 3H, H-4, H-6a, H-6b), 1.56 (s, 3H,
(CH3)2C), 1.43 (s, 3H, (CH3)2C); 13C NMR (125 MHz,
CDCl3, dC) 155.0 (Ar), 150.1 (Ar), 138.3 (Ar), 138.2
(Ar), 128.3 (Ar · 2), 128.2 (Ar · 2), 127.9 (Ar · 2),
127.6 (Ar · 2), 127.4 (Ar · 2), 118.1 (Ar · 2), 114.6
(Ar · 2), 109.6 ((CH3)2C), 96.6 (C-1), 78.8 (C-3), 75.9
1
ꢀ18.5 (c 0.9, CH3OH); H NMR (500 MHz, CD3OD,
dH) 4.38 (d, 1H, J1,2 = 8.4 Hz, H-1), 3.90–3.84 (m, 2H,
octyl OCH2, H-6a), 3.67 (dd, 1H, J5,6b = 5.7 Hz,
J6a,6b = 10.4 Hz, H-6b), 3.62 (dd, 1H, J1,2 = 8.4 Hz,
J2,3 = 10.5 Hz, H-2), 3.48–3.42 (m, 2H, octyl OCH2,
H-3), 3.34–3.22 (m, 4H, octyl CH2N3, H-5, H-4), 1.96
(s, 3H, acetyl CH3), 1.60–1.50 (m, 4H, octyl CH2),
1.40–1.30 (m, 8H, octyl CH2); 13C NMR (125 MHz,
CD3OD, dC) 173.6 (C@O), 102.7 (C-1), 78.0 (C-4), 76.1
(C-3), 72.2 (C-5), 70.6 (octyl OCH2), 62.9 (C-6), 57.5
(C-2), 52.5 (octyl CH2N3), 30.6 (octyl CH2), 30.4 (octyl
CH2), 30.3 (octyl CH2), 29.9 (octyl CH2), 27.8 (octyl
CH2), 27.0 (octyl CH2), 23.0 (acetyl CH3). ESIMS m/z:
calcd for [C16H30N4O6]Na+, 397.2058; found, 397.2058.
1.6. p-Methoxyphenyl 2,3-O-isopropylidene-a-D-manno-
pyranoside (8)
To a mixture of 76 (3.27 g, 11.3 mmol) in 4:1 acetone–
DMF (70 mL), dimethoxypropane (24.5 mL, 200 mmol)
was added, and the solution was stirred for 4 days. TLC