234
Y.E. Ts6etko6 et al. / Carbohydrate Research 335 (2001) 221–243
aq AcOH (50 mL) for 15 min. The mixture
was concentrated, and residual AcOH was
coevaporated with toluene. Column chro-
matography of the residue (1:1 toluene–
EtOAc) gave 6 (8.68g, 73.5%): mp 141–143 °C
Benzyl 3,4-anhydro-2-azido-2,6-dideoxy-i-
-allopyranoside (11).—Compound 8 (5.66 g,
L
24 mmol) was treated with Tf2O (6.71 mL, 40
mmol) in the presence of py (5.82 mL, 72
mmol) in CH2Cl2 (75 mL) as described in the
preparation of 7. The crude triflate 10 ob-
tained was dissolved in DMF (50 mL), sodium
azide (7.8 g, 120 mmol) was added, and the
mixture was stirred for 1 h at rt. The mixture
was diluted with EtOAc, washed thoroughly
with water, dried with MgSO4 and concen-
trated. Column chromatography of the
residue (85:15 light petroleum–EtOAc) gave
11 (5.22 g, 83%): mp 52–54 °C (hexane); [h]D
+78° (c 1.1). 1H NMR: l 1.44 (d, 3 H, J5,6 6.8
Hz, H-6), 3.17 (d, 1 H, H-4), 3.45 (dd, 1 H,
J3,4 4.2 Hz, H-3), 3.69 (dd, 1 H, J2,3 2.2 Hz,
H-2), 4.08 (q, 1 H, H-5), 4.58 (d, 1 H, J1,2 7.6
Hz, H-1), 4.62, 4.87 (2 d, 2 H, Jgem 11.4 Hz,
PhCH2), 7.29–7.41 (m, 5 H, Ph). Anal. Calcd
for C13H15N3O3: C, 59.76; H, 5.79; N, 16.08.
Found: C, 59.64; H, 5.80; N, 16.00.
1
(EtOAc–hexane); [h]D +64.5° (c 1.8). H
NMR: l, 1.32 (d, 3 H, J5,6 6.2 Hz, H-6), 2.12,
2.21 (2 s, 6 H, 2 CH3CO), 2.48 (d, 1 H, J3,OH
7.3 Hz, OH), 3.46 (dq, 1 H, H-5), 3.75 (ddd, 1
H, J3,4 10.0 Hz, H-3), 4.57 (s, 1 H, H-1), 4.65,
4.90 (2 d, 2 H, Jgem 12.0 Hz, PhCH2), 4.84 (t,
1 H, J4,5 9.5 Hz, H-4), 5.43 (d, 1 H, J2,3 3.5
Hz, H-2), 7.29–7.38 (m, 5 H, Ph). Anal. Calcd
for C17H22O7: C, 60.34; H, 6.55. Found: C,
60.43; H, 6.63.
Benzyl
3,4-anhydro-6-deoxy-i- -altropy-
L
ranoside (8).—A solution of trifluoromethane-
sulfonic anhydride (Tf2O) (8.4 mL, 50 mmol)
in CH2Cl2 (10 mL) was added dropwise at
0 °C to a solution of 6 (10.2 g, 30.2 mmol) and
py (7.27 mL, 90 mmol) in CH2Cl2 (100 mL),
and the mixture was stirred at the same tem-
perature for 45 min. The solution was diluted
with CHCl3, washed successively with ice-cold
water, M HCl, and water, and concentrated.
The crude triflate 7 was dissolved in MeOH
(70 mL) and treated with 2 M CH3ONa (30
mL) for 30 min at rt. The solution was neu-
tralised with AcOH, taken to dryness, and the
residue was distributed between water and
CHCl3. The organic layer was separated, and
the water layer was extracted twice with
CHCl3. The combined organic solution was
concentrated, and the residue was subjected to
column chromatography (3:2 toluene–EtOAc)
to give 8 (5.66 g, 79%) as a syrup: [h]D +87°
Benzyl 2,4-diazido-2,4,6-trideoxy-i- -gulo-
L
pyranoside (12).—A solution of sodium azide
(6.7 g, 103 mmol) and ammonium chloride
(5.51 g, 103 mmol) in water (25 mL) was
added to a solution of 11 (5.38 g, 20.6 mmol)
in EtOH (100 mL). The mixture was boiled
under reflux for 7 h, EtOH was distilled off,
and the remaining aqueous solution was ex-
tracted three times with CHCl3. The combined
extract was concentrated, and the residue was
subjected to column chromatography (92:8
toluene–EtOAc) to yield 12 (5.40 g, 86%) as a
1
syrup: [h]D +63° (c 2). H NMR: l 1.37 (d, 3
1
H, J5,6 6.5 Hz, H-6), 2.47 (s, 1 H, OH), 3.47
(dd, 1 H, J4,5 1.3 Hz, J3,4 3.4 Hz, H-4), 3.66
(dd, 1 H, J2,3 3.1 Hz, H-2), 4.14 (m, 2 H,
H-3,5), 4.67, 4.96 (2 d, 2 H, Jgem 11.8 Hz,
PhCH2), 4.77 (d, 1 H, J1,2 8.1 Hz, H-1),
7.30–7.41 (m, 5 H, Ph). Anal. Calcd for
C13H16N6O3: C, 51.31; H, 5.30; N, 27.62.
Found: C, 51.44; H, 5.35; N, 27.63.
(c 2.6). H NMR: l 1.47 (d, 3 H, J5,6 7.0 Hz,
H-6), 2.63 (br, s, 1 H, OH), 3.04 (d, 1 H, H-4),
3.44 (dd, 1 H, J3,4 3.9 Hz, H-3), 4.02 (t, 1 H,
J2,3 1.7 Hz, H-2), 4.07 (q, 1 H, H-5), 4.54 (d 1
H, J1,2 1.6 Hz, H-1), 4.58, 4.89 (2 d, 2 H, Jgem
11.9 Hz, PhCH2), 7.27–7.42 (m, 5 H, Ph).
Anal. Calcd for C13H16O4: C, 66.08; H, 6.83.
Found: C, 66.13; H, 6.95.
Conventional acetylation of 12 with Ac2O
Conventional acetylation of 8 with Ac2O in
1
1
in py gave 3-acetate 13. H NMR: l 1.38 (d, 3
py afforded 2-acetate 9. H NMR: l 1.50 (d, 3
H, J5,6 6.5 Hz, H-6), 2.05 (s, 3 H, CH3CO),
3.48 (dd, 1 H, J4,5 1.7 Hz, H-4), 3.69 (dd, 1 H,
J2,3 3.4 Hz, H-2), 4.03 (dq, 1 H, H-5), 4.69,
4.96 (2 d, 2 H, Jgem 11.8 Hz, PhCH2), 4.79 (d,
1 H, J1,2 8.1 Hz, H-1), 5.33 (t, 1 H, J3,4 3.5 Hz,
H-3), 7.30–7.42 (m, 5 H, Ph).
H, J5,6 7.5 Hz, H-6), 2.17 (s, 3 H, CH3CO),
3.07 (d, 1 H, H-4), 3.39 (dd, 1 H, J3,4 4.0 Hz,
H-3), 4.10 (q, 1 H, H-5), 4.57, 4.86 (2 d, 2 H,
Jgem 13.2 Hz, PhCH2), 4.64 (d, 1 H, J1,2 2.1
Hz, H-1), 5.25 (t, 1 H, J2,3 1.8 Hz, H-2),
7.25–7.38 (m, 5 H, Ph).