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R. Saksena et al. / Carbohydrate Research 340 (2005) 1591–1600
0
and that one product, showing slower chromatographic
mobility than 14, was formed. After concentration,
chromatography of the residue gave 15 (83 mg, 91%),
which crystallized as a mixture of anomers (a:b ꢀ 3:1,
NMR), mp 168–170 °C (from i-Pr2O containing a few
drops of EtOAc), [a]D +5.2 (c 0.4). 1H NMR (a-anomer,
CDCl3): d 5.89 (d, JNH,4 9.0 Hz, NH), 5.33 (d, J1,2
3.2 Hz, H-1), 4.83, 4.62 (2d, partially overlapped, 2J
11.7 Hz, CH2Ph), 3.96–3.91 (m, H-5), 3.81 (q, J
9.4 Hz, H-4), 3.71 (t, partially overlapped, H-3), 3.51
(s, partially overlapped, OCH3), 3.39 (dd, J2,3 8.6 Hz,
2CH3 ), 1.17 (d, J5,6 6.3 Hz, H-6); 13C NMR (a-anomer,
D2O): d 176.76 (CO), 92.05 (C-1), 83.86 (C-2), 73.02 (C-
30), 72.41 (C-3), 69.00 (C-5), 60.37 (OCH3), 59.46 (C-4),
1
0
0
51.60 (C-2 ), 31.01, 30.86 (2CH3 ), 19.80 (C-6); H NMR
(b-anomer, D2O): d 4.63 (d, J1,2 7.9 Hz, H-1), 3.63 (par-
tially overlapped, H-4), 3.61 (s, CH3O), 3.58–3.51 (m,
H-5, incl. 3.53, t, J 9.3 Hz, H-3), 3.04 (dd, 1H, J2,3
9.3 Hz, H-2), 2.48–2.44 (m, H-20), 1.31, 1.30 (2s,
2CH3 ), 1.20 (d, 3H, J5,6 6.1 Hz, H-6); 13C NMR (b-ano-
0
mer, D2O): d 176.76 (CO), 98.29 (C-1), 87.10 (C-2),
75.90 (C-3), 73.64 (C-5), 73.02 (C-30), 60.37 (OCH3),
2
0
H-2), 2.15 (dd, J 14.8 Hz, H-20a,b), 1.23, 1.20 (2s,
59.29 (C-4), 51.64 (C-2 ), 31.04, 30.84 (2CH3 ), 19.80
(C-6); ESIMS: m/z 330 ([M+Na]+).
0
2CH3 ), 1.22 (d, J5,6 6.7 Hz, H-6); 13C NMR (a-anomer,
0
CDCl3): d 172.40 (CO), 90.23 (JC,H 168 Hz, C-1), 82.46
(C-2), 77.17 (C-3), 73.86 (CH2Ph), 69.55 (C-30), 67.24
(C-5), 58.62 (OCH3), 54.83 (C-4), 47.73 (C-20), 29.30,
3.12. Methyl 4-azido-3-O-benzyl-4,6-dideoxy-b-D-gluco-
pyranoside (19)
29.27 (2CH3 ), 18.06 (C-6); 1H NMR (b-anomer,
0
CDCl3): d 5.89 (d, JNH,4 9.0 Hz, NH), 4.85, 4.63 (2d,
partially overlapped, J 11.5 Hz, CH2Ph), 4.61 (d, par-
Triflic anhydride (0.4 mL, 2.5 mmol) was added at 0 °C
to a stirred solution of methyl 4-azido-3-O-benzyl-4,6-
dideoxy-b-D-mannopyranoside (17,29 500 mg, 1.7 mmol)
in CH2Cl2 (15 mL) containing pyridine (0.85 mL,
10 mmol). The cooling was removed and, when TLC
(4:1 hexane–EtOAc) showed that the reaction was com-
plete (ꢀ1 h) the mixture was concentrated. Chromato-
graphy gave pure methyl 4-azido-3-O-benzyl-4,6-dide-
oxy-2-O-trifluoromethanesulfonyl-b-D-glucopyranoside
2
tially overlapped, H-1), ꢀ3.71 (m, partially overlapped,
H-4), 3.62 (s, 3H, OCH3), 3.56–3.46 (m, partially over-
lapped, H-3,5), 3.15 (t, J 8.2 Hz, H-2), 2.15 (dd, 2J
14.8 Hz, H-20a,b), 1.25 (d, J5,6 6.3 Hz, H-6), 1.23, 1.20
(2s, 2CH3 ); 1H NMR (b-anomer, C6D6): d 5.02 (d,
0
2
JNH,4 8.9 Hz, NH), 4.79, 4.53 (2d, J 11.7 Hz, CH2Ph),
4.38 (d, J1,2 8.5 Hz, H-1), ꢀ3.76–3.71 (m, partially over-
lapped, H-5), 3.56 (q, J 9.8 Hz, H-4), 3.49 (s, OCH3),
3.31 (t, H-3), 2.99 (dd, J2,3 8.3 Hz, H-2), 1.98, 1.87
1
(18, 570 mg, ꢀ100%). H NMR (CDCl3): d 5.12 (br d,
2
1H, H-2), 4.85, 4.57 (2d, 2H, J 11.3 Hz, CH2Ph), 4.36
2
0
0
(2d, J 14.8 Hz, H-2 a,b), 1.13, 1.11 (2s, 2CH3 ), 1.07
(d, 1H, J1,2 ꢀ 0.6 Hz, H-1), 3.52 (s, 3H, OCH3), 3.48
(dd, 1H, J2,3 2.8, J3,4 9.9 Hz, H-3), 3.37 (t, 1H, J
9.9 Hz, H-4), 3.23–3.13 (m, 1H, H-5), 1.39 (d, 3H, J5,6
6.0 Hz, H-6); 13C NMR (CDCl3): d 97.87 (C-1), 80.76
(C-2), 77.00 (C-3), 72.18 (CH2Ph), 71.30 (C-5), 63.39
(C-4), 56.87 (OCH3), 18.16 (C-6); ESIMS: m/z 448
([M+Na]+).
(d, J5,6 6.1 Hz, H-6); 13C NMR (b-anomer, CDCl3): d
172.53 (CO), 97.07 (JC,H 161 Hz, C-1), 85.45 (C-2),
80.14 (C-3), 73.77 (CH2Ph), 70.97 (C-5), 69.53 (C-30),
60.41 (OCH3), 55.70 (C-4), 47.83 (C-20), 29.33, 29.30
+
(2CH3 ), 18.17 (C-6); CIMS: m/z 390 ([M+Na] ). Anal.
0
Calcd for C19H29NO6: C, 62.11; H, 7.96; N, 3.81.
Found: C, 61.85; H, 7.87; N, 3.78.
NaNO2 (267 mg, 3.87 mmol) was added to a solution
of the above triflate (550 mg, 1.29 mmol) in DMF
(5 mL), and the solution was stirred at room tempera-
ture for 24 h. TLC (4:1 hexane–EtOAc) showed that
the reaction was complete and that three products,
two showing faster and one slower mobility than the
starting material, were formed. The mixture containing
some precipitate was concentrated, and the residue
was chromatographed to give the desired, title com-
pound 19 (276 mg, 73%), mp 68.5–69 °C (from i-Pr2O–
hexane), [a]D ꢁ9 (c 0.4). 1H NMR (CDCl3): d 4.95,
4.85 (2d, 2H, 2J 11 Hz, CH2Ph), 4.11 (d, 1H, J1,2
7.7 Hz, H-1), 3.54–3.51 (m, 4H, H-2, incl. 3.54, s,
OCH3), 3.44 (t, 1H, J 9.1 Hz, H-3), 3.27–3.23 (m, 1H,
H-5), 3.15 (t, 1H, J 9.5 Hz, H-4), 2.72 (d, 1H, J2,OH
2.6 Hz, OH), 1.34 (d, 3H, J5,6 6.1 Hz, H-6); 13C NMR
(CDCl3): d 103.38 (C-1), 82.35 (C-3), 74.95 (CH2Ph),
74.79 (C-2), 70.66 (C-5), 67.25 (C-4), 57.08 (OCH3),
18.35 (C-6); ESIMS: m/z 316 ([M+Na]+). Anal. Calcd
for C14H19N3O4: C, 57.33; H, 6.53; N, 14.33. Found:
C, 57.33; H, 6.58; N, 14.33.
3.11. 4,6-Dideoxy-4-(3-hydroxy-3-methylbutanamido)-2-
O-methyl-a,b-D-glucopyranose (anthrose, 16)
A
solution of the above anthroside 15 (40 mg,
0.10 mmol) in 1:1 H2O–MeOH (5 mL) was stirred under
hydrogen for 48 h at 50 °C in the presence of 5% Pd/C
catalyst (40 mg). TLC (4:1 CH2Cl2–MeOH) showed that
the reaction was complete and that one product was
formed. After filtration and concentration of the filtrate,
the residue was chromatographed, mainly to remove
residual catalyst. Fractions containing anthrose were
concentrated, a solution of the residue in H2O was fil-
tered through a syringe filter (0.02 lm porosity) and
freeze dried, to give anthrose (16 anomeric mixture,
a:b ꢀ 4.5:5.5, NMR) as a white solid in virtually theo-
1
retical yield. H NMR (a-anomer, D2O): d 5.44 (d, J1,2
3.6 Hz, H-1), 3.99–3.94 (m, H-5), 3.73 (t, J 9.7 Hz, H-
3), 3.63 (m, partially overlapped, H-4), 3.48 (s, OCH3),
3.32 (dd, H-2), 2.48–2.44 (m, H-20), 1.31, 1.30 (2s,