while anisaldehyde (8.7 mL, 71.5 mmol) was added dropwise. When a precipitate formed after
~1 h, the reaction was stored at -18 ºC overnight.
7 The mixture, which had frozen, was then
thawed and the precipitate was filtered off and washed with water (2 x 100 mL) and then
washed with MeOH-Et2O (1:1, 2 x 100 mL). The white solid obtained was then dried under
diminished pressure to give 2 (16.9 g, 69 %); mp 162.3-162.6 ºC dec. (lit
1 164-168 ºC, dec.);
[α]D = +22.8 (c 1, DMSO) (lit
1 +28.0 (c 0.84, DMSO)). The
1 H and
13 C-NMR data were in
good agreement with reported literature data:
8 1 H-NMR (DMSO-d6, 500 MHz) δ 8.10 (1H, s,
CH=N), 7.67 (2H, d, J = 8.7, Ar-H), 6.97 (2H, d, J=8.6, Ar-H), 6.49 (1H, d, J=6.8, OH-1), 4.88
(1H, d, J = 5.3, OH-4), 4.77 (1H, d, J = 5.7, OH-3), 4.67 (1H, t, J = 7.3, H-1), 4.51 (1H, t, J =
5.8, OH-6), 3.78 (3H, s, OMe), 3.71 (1H, ddd, J = 11.8, 5.5, 2.1, H-6a), 3.47 (1H, dt, J = 11.8,
6.0, H-6b), 3.40 (1H, td, J=8.9, 5.6, H-3), 3.22 (1H, ddd, J = 8.5, 6.0, 2.0, H-5), 3.12 (1H, td, J
= 9.1, 5.3, H-4), 2.80 – 2.74 (1H, m, H-2);
13
C-NMR (126 MHz, DMSO-d6) δ 161.63
(ArCH=N), 161.47, 130.04, 129.55, 114.33 (each Ar-C), 96.07 (C-1), 78.62 (C-2), 77.30 (C5), 75.03 (C-3), 70.80 (C-4), 61.72 (C-6), 55.71 (OMe); HRMS (ESI): [M+H]
+ calcd. for
C14H20NO6, 298.1291; found 298.1300; FT-IR 3483, 3310, 2933, 1604, 1515, 1267 1104,
1061, 1023, 834 cm-1. Anal. calcd for C14H19NO6: C, 56.6; H, 6.40, N, 4.70. Found: C, 56.4;
H, 6.24; N, 4.56.
2-Amino-2-deoxy-N-(p-methoxybenzylidene)-1,3,4,6-tetra-O-benzoyl-β-D-glucopyranose
(3). Benzoyl chloride (9.7 mL, 84.0 mmol) was added slowly at 0ºC to a solution of he
benzylidene derivative 2 (5.00 g, 16.8 mmol) in pyridine (50 mL). The mixture was then
allowed to attain room temperature and stirred for 12 h. EtOAc was added and the mixture was
washed with 1.0 M HCl (x 2), satd aq NaHCO3, and brine. After drying and concentration the
title compound was crystallized from EtOH (10.26 g, 86 %), mp 190.7-191.5 ºC (lit
8 190-191
ºC); [α]D
20 +56.6 (c 1, CHCl3) (lit
8
[α]D
24 +59.3, (c 1, CHCl3);
1 H NMR (500 MHz, CDCl3): δ
8.28 (s, 1H, ArCH=N), 8.02 (m, Ar-H), 7.94-7.90 (m, 2H, Ar-H), 7.85-7.81 (m, 2H, Ar-H),
~1 h, the reaction was stored at -18 ºC overnight.
7 The mixture, which had frozen, was then
thawed and the precipitate was filtered off and washed with water (2 x 100 mL) and then
washed with MeOH-Et2O (1:1, 2 x 100 mL). The white solid obtained was then dried under
diminished pressure to give 2 (16.9 g, 69 %); mp 162.3-162.6 ºC dec. (lit
1 164-168 ºC, dec.);
[α]D = +22.8 (c 1, DMSO) (lit
1 +28.0 (c 0.84, DMSO)). The
1 H and
13 C-NMR data were in
good agreement with reported literature data:
8 1 H-NMR (DMSO-d6, 500 MHz) δ 8.10 (1H, s,
CH=N), 7.67 (2H, d, J = 8.7, Ar-H), 6.97 (2H, d, J=8.6, Ar-H), 6.49 (1H, d, J=6.8, OH-1), 4.88
(1H, d, J = 5.3, OH-4), 4.77 (1H, d, J = 5.7, OH-3), 4.67 (1H, t, J = 7.3, H-1), 4.51 (1H, t, J =
5.8, OH-6), 3.78 (3H, s, OMe), 3.71 (1H, ddd, J = 11.8, 5.5, 2.1, H-6a), 3.47 (1H, dt, J = 11.8,
6.0, H-6b), 3.40 (1H, td, J=8.9, 5.6, H-3), 3.22 (1H, ddd, J = 8.5, 6.0, 2.0, H-5), 3.12 (1H, td, J
= 9.1, 5.3, H-4), 2.80 – 2.74 (1H, m, H-2);
13
C-NMR (126 MHz, DMSO-d6) δ 161.63
(ArCH=N), 161.47, 130.04, 129.55, 114.33 (each Ar-C), 96.07 (C-1), 78.62 (C-2), 77.30 (C5), 75.03 (C-3), 70.80 (C-4), 61.72 (C-6), 55.71 (OMe); HRMS (ESI): [M+H]
+ calcd. for
C14H20NO6, 298.1291; found 298.1300; FT-IR 3483, 3310, 2933, 1604, 1515, 1267 1104,
1061, 1023, 834 cm-1. Anal. calcd for C14H19NO6: C, 56.6; H, 6.40, N, 4.70. Found: C, 56.4;
H, 6.24; N, 4.56.
2-Amino-2-deoxy-N-(p-methoxybenzylidene)-1,3,4,6-tetra-O-benzoyl-β-D-glucopyranose
(3). Benzoyl chloride (9.7 mL, 84.0 mmol) was added slowly at 0ºC to a solution of he
benzylidene derivative 2 (5.00 g, 16.8 mmol) in pyridine (50 mL). The mixture was then
allowed to attain room temperature and stirred for 12 h. EtOAc was added and the mixture was
washed with 1.0 M HCl (x 2), satd aq NaHCO3, and brine. After drying and concentration the
title compound was crystallized from EtOH (10.26 g, 86 %), mp 190.7-191.5 ºC (lit
8 190-191
ºC); [α]D
20 +56.6 (c 1, CHCl3) (lit
8
[α]D
24 +59.3, (c 1, CHCl3);
1 H NMR (500 MHz, CDCl3): δ
8.28 (s, 1H, ArCH=N), 8.02 (m, Ar-H), 7.94-7.90 (m, 2H, Ar-H), 7.85-7.81 (m, 2H, Ar-H),