A.M. Go´mez et al. / Carbohydrate Research 320 (1999) 138–142
141
Compound 7 (338 mg, a-7:b-7=1.6:1) was
submitted to hydrogenation (6 h) under the
conditions reported by Toma [7], after which
time the reaction mixture was divided into two
halves. The first half was filtered and sepa-
rated by chromatography to yield compound
2 (15 mg, 12%) along with recovered 7 (146
mg, a-7:b-7=2.5:1, 86%). The second half
was treated with a second amount of catalyst
as before and resubmitted to hydrogenation
(42 h) to afford, after flash chromatography,
hemiacetal 2 (106.3 mg, 85%) and a-7 (20 mg,
12%).
71.1, 70.1, 67.2, 62.9, 62.7, 29.1, 26.4, 18.2.
Anal. Calcd for C19H26O6: C, 65.13; H, 7.48.
Found: C, 65.22; H, 7.57.
Benzyl
2,3:4,6-di-O-isopropylidene-i- -
D
galactopyranoside (b-12).—(287 mg, 82%), mp
125–127 °C, lit 128–130 °C [14], [h]D −51.6°
(c 1.0, CHCl3), lit −52° (c 1.0, CHCl3) [14];
1H NMR (CDCl3): l 7.25–7.38 (m, 5 H), 4.96
and 4.59 (2d, 2 H, J 12.0 Hz, OCH2Ph), 4.68
(d, 1 H, J1,2 7.8 Hz, H-1), 4.41 (m, 1 H, H-4),
3.97–4.17 (m, 3 H, 2H-6, H-2), 3.51 (dd, 1 H,
J 2.8, J 9.5 Hz, H-3), 3.29 (m, 1H, H-5), 1.48
(s, 3 H, Me), 1.47 (s, 3 H, Me), 1.43 (s, 3 H,
13
Me), 1.38 (s, 3 H, Me); C NMR (CDCl3): l
Benzyl 2,3:4,6-di-O-isopropylidene-h- -glu-
D
137.0, 128.1, 127.8, 127.5, 110.8, 100.8, 98.4,
78.0, 72.6, 69.8, 67.2, 66.1, 62.7, 28.8, 26.5,
26.3, 18.5. Anal. Calcd for C19H26O6: C, 65.13;
H, 7.48. Found: C, 64.81; H, 7.32.
copyranoside (a-7).—(238 mg, 68%), [h]D+
1
90.8° (c 1.1, CHCl3); H NMR (CDCl3): l
7.26–7.37 (m, 5 H, Ph), 5.25 (d, 1 H, J1,2 2.6
Hz, H-1), 4.78 and 4.65 (2d, 2 H, J 12.4 Hz,
OCH2Ph), 4.11 (t, 1 H, J 9.2 Hz, H-3), 3.90 (t,
1 H, J 9.5 Hz, H-4), 3.81 (m, 2 H, 2H-6), 3.36
(m, 2 H, H-2, H-5), 1.54 (s, 3 H, Me), 1.49 (s,
3 H, Me), 1.46 (s, 3 H, Me), 1.43 (s, 3 H, Me);
13C NMR (CDCl3): l 137.1, 128.3, 127.7,
127.5, 111.4, 99.6, 97.3, 76.8, 73.9, 73.7, 69.9,
65.1, 62.2, 28.9, 26.8, 26.3, 19.1. Anal. Calcd
for C19H26O6: C, 65.13; H, 7.48. Found: C,
64.89; H, 7.35.
2,3:4,6-Di-O-isopropylidene- -glucopyranose
D
(2).—(272 mg, 91% yield), [h]D −32.3° (c 1.0,
CHCl3), lit −34° (c 1.6, CHCl3) [7]; (3:2
1
hexane:EtOAc) H NMR (CDCl3): l (selected
peaks) 1.25–1.50 (cluster of singlets, 12 H),
3.4–5.0 (m, 7 H), 9.77 (d, 0.10 H, J 1.5 Hz,
CHO).
2,3:4,6-Di-O-isopropylidene- -galactopyran-
D
ose (3).—(245 mg, 89% yield), [h]D −10.7° (c
1.0, CHCl3), lit −8° (c 2.0, CHCl3) [7]; (3:2
Benzyl 2,3:4,6-di-O-isopropylidene-i- -glu-
D
1
hexane:EtOAc) H NMR (CDCl3): l (selected
copyranoside (b-7).—(262 mg, 75%), mp 124–
peaks) 1.30–1.50 (cluster of singlets, 12 H),
3.4–5.1 (m, 7 H), 9.64 (d, 0.10 H, CHO).
1
125 °C, [h]D −62.5° (c 1.6, CHCl3); H NMR
(CDCl3): l 7.25–7.38 (m, 5 H, Ph), 4.90 and
4.69 (2d, 2 H, J 11.8 Hz, OCH2Ph), 4.77 (d, 1
H, J1,2 7.8 Hz, H-1), 3.85–3.98 (m, 3 H, H-3,
H-4, H-6), 3.63 (t, 1 H, J 9.2 Hz, H-6%), 3.46
(t, 1 H, J 8.4 Hz, H-2), 3.25 (dt, 1 H, Jd 6.2,
Jt 9.2 Hz, H-5), 1.53 (s, 3 H), 1.45 (s, 6 H,
2,3:4,6 - Di - O - isopropylidene -
D
- glucitol
(4).—Hydrogenation of 7 (159 mg) was car-
ried out at 35 psi using a 20% w/w proportion
of 10% Pd/C during 36 h, to yield after
column chromatography
D
-glucitol diace-
tonide (4) (93 mg, 78%).[h]D −17.3 (c 0.8,
13
2Me), 1.43 (s, 3 H, Me), 1.43 (s, 3 H, Me); C
1
CHCl3); H NMR (CDCl3): l 4.18–4.24 (m, 2
NMR (CDCl3): l 136.5, 128.3, 128.1, 127.9,
112.1, 101.1, 99.7, 77.8, 77.5, 72.6, 70.7, 69.6,
62.1, 28.9, 26.6, 26.4, 19.0. Anal. Calcd for
C19H26O6: C, 65.13; H, 7.48. Found: C, 65.39;
H, 7.55.
H), 3.59–3.92 (m, 6 H), 3.21 (d, 1 H, J 2.4 Hz,
OH), 2.45 (t, 1 H, J 5.7 Hz, OH), 1.43 (s, 3 H,
Me), 1.41 (s, 3 H, Me), 1.39 (s, 3 H, Me), 1.35
(s, 3 H, Me); 13C NMR (CDCl3): l 109.4,
99.0, 77.3, 76.6, 72.0, 64.0, 63.5, 62.7, 28.0,
27.0, 26.6, 19.2. Anal. Calcd for C12H22O6: C,
54.95; H, 8.45. Found: C, 54.78; H, 8.23.
Compound 2 (16 mg, 13.5%) was also
isolated.
Benzyl
2,3:4,6-di-O-isopropylidene-h- -
D
galactopyranoside (a-12).—(262 mg, 75%),
[h]D+114.1° (c 0.6, CHCl3); 1H NMR
(CDCl3): l 7.25–7.35 (m, 5 H, Ph), 5.39 (d, 1
H, J1,2 2.7 Hz, H-1), 4.71 (s, 2 H, OCH2Ph),
4.46 (m, 1 H, H-4), 4.01–4.21 (m, 3 H, H-2,
H-3 H-6), 3.81 (dd, 1 H, J 1.5, J 12.9 Hz,
H-6%), 3.28 (m, 1 H, H-5), 1.47 (s, 9 H, 3 Me),
1.44 (s, 3 H); 13C NMR (CDCl3): l 137.5,
128.2, 128.1, 127.5, 110.1, 98.3, 97.8, 72.6,
Acknowledgements
This research was supported by funds from
the Direccio´n General de Ensen˜anza Superior