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B. Wu et al. / Tetrahedron 71 (2015) 4023e4030
4.10. Methyl 3-thio-
a
-
D
-mannopyranoside 4
(57 mg, 78%). 1H NMR (400 MHz, CDCl3)
d
¼8.06e7.31 (m, 15H,
Phx3), 5.74 (t, J¼10.6 Hz 1H, H-4), 5.31 (dd, J¼1.6 Hz, 2.9 Hz, 1H, H-
2), 4.89 (d, J¼1.5 Hz, 1H, H-1), 4.66 (dd, J¼3.0 Hz, 11.3 Hz, 1H, H-3),
4.63e4.56 (m, 1H, H-6), 4.47e4.35 (m, 2H, H-5, H-60), 3.51 (s, 3H,
Prepared from methyl 2,4,6-tri-O-benzoyl-3-S-acetyl-a-D-man-
nopyranoside 21 in light of the general deacetylation of thio-
containing carbohydrate derivatives procedure, 14% total yield. 1H
OMe), 2.13 (s, 3H, SAc). 13C NMR (100 MHz, CDCl3)
d
¼193.4, 166.2,
NMR (400 MHz, D2O)
d
¼4.83 (d, J¼1.2 Hz, 1H, H-1), 3.95 (m, 2H, H-
165.7, 165.5, 133.7, 133.6, 133.1, 130.1, 130.0, 129.8, 129.3, 129.2,
128.8, 128.7, 128.5, 97.7, 73.3, 69.7, 67.3, 63.6, 55.6, 44.2, 30.6. HRMS
(ESI-TOF) m/z: [MþNa]þ Calcd for C30H28O9SNa 587.1352; found
587.1348.
6,H-2), 3.81 (dd, J¼6.1 Hz, 12.1 Hz, 1H, H-60), 3.70 (m, 1H, H-5), 3.56
(t, J¼10.2 Hz, 1H, H-4), 3.48 (s, 3H, OMe), 3.19 (dd, J¼3.8 Hz, 7.6 Hz,
1H, H-3). 13C NMR (100 MHz, D2O)
d¼100.0, 73.6, 71.3, 67.8, 61.2,
54.6, 43.6. HRMS (ESI-TOF) m/z: [MþNa]þ Calcd for C7H14O5SNa
233.0460; found 233.0478.
4.14. Methyl 2-thio-
a-D-mannopyranoside 5
4.11. Methyl 2,3,6-tri-O-benzoyl-
a
-D
-altropyranoside 19 and
prepared from 3,4,6-tri-O-acetyl-2-S-acetyl-a-D-mannopyrano-
methyl 2,4,6-tri-O-benzoyl- -altropyranoside 20
a
-
D
side 27 according to the general deacetylation of thio-containing
carbohydrate derivatives procedure, 51% total yield. 1H NMR
Starting from methyl-
2 mmol), methyl 3-O-benzyl-
was obtained in light of the literature.58 Benzylation with BzCl
(903 L) and pyridine (4 mL) afforded methyl 2,4,6-tri-O-benzoyl-
3-O-benzyl- -mannopyranoside (736 mg, 95%). After removal of
a
-
a
D
-mannopyranoside 14 (304 mg,
(400 MHz, D2O)
d
¼4.94 (s, 1H, H-1), 4.04 (dd, J¼4.9 Hz, 8.8 Hz, 1H,
-
D
-mannopyranoside (369 mg, 83%)
H-3), 3.88 (dd, J¼2.0 Hz, 12.3 Hz, 1H, H-6), 3.78 (dd, J¼5.3 Hz,
12.3 Hz, 1H, H-60), 3.73e3.60 (m, 2H, H-4, H-5), 3.45 (d, J¼5.0 Hz,
m
1H, H-2), 3.41 (s, 3H, OMe). 13C NMR (100 MHz, D2O)
d
¼102.4, 72.9,
a-
D
69.0, 66.5, 60.7, 54.8, 44.4. HRMS (ESI-TOF) m/z: [MþNa]þ Calcd for
benzyl group by catalytic hydrogenation, compound 18 (612 mg,
98%) was given. To a solution of compound 18 (200 mg) in DCM
C7H14O5SNa 233.0460; found 233.0460.
(5 mL) was added pyridine (210
fluoromethanesulfonic anhydride (200
m
L) at ꢁ30 ꢀC. Tri-
4.15. Methyl 2-S-acetyl-3,4,6-tri-O-acetyl-a-D-mannopyrano-
side 27
mL) in DCM (2 mL) was
added dropwise, and the mixture was warmed to ꢁ10 ꢀC and
stirred for 4 h. The resulting mixture was subsequently extracted
and concentrated. The residue was dissolved in DMF with the ad-
dition of KNO2 (101 mg, 3.0 equiv). The mixture was stirred at 50 ꢀC
for 6 h. After extracted and concentrated, the crude product was
purified by flash chromatography with solvent system petrol/ethyl
acetate 7:1 giving compound 19 (110 mg, 55%) and compound 20
(66 mg, 33%). For compound 19: 1H NMR (400 MHz, CDCl3)
Prepared from methyl 3,6-di-O-acetyl-a-D-galactoside 23
according to the general synthesis of triflate derivatives and general
double serial inversion procedure. The yield over three steps is 70%.
Compound 23 was obtained in 86% yield starting from methyl
a-D-
galactoside 22 in light of the literature.54 1H NMR (400 MHz, CDCl3)
d
¼5.54 (dd, J¼4.8 Hz, 9.9 Hz, 1H, H-3), 5.05 (t, J¼10.0, 1H, H-4), 4.73
(s, 1H, H-1), 4.24 (dd, J¼1.1 Hz, 4.7 Hz, 1H, H-2), 4.18 (dd, J¼4.9 Hz,
12.2 Hz, 1H, H-6), 4.07 (dd, J¼2.4 Hz, 12.2 Hz, 1H, H-60), 3.93 (ddd,
J¼2.4 Hz, 4.8 Hz, 9.9 Hz,1H, H-5), 3.37 (s, 3H, OMe), 2.34 (s, 3H, SAc),
2.08 (s, 3H, OAc), 2.00 (s, 3H, OAc), 1.93 (s, 3H, OAc). 13C NMR
d
¼8.13e7.32 (m, 15H, Phx3), 5.57 (t, J¼3.3 Hz, 1H, H-3), 5.36 (d,
J¼3.3 Hz, 1H), 4.84 (s, 1H, H-1), 4.77 (dd, J¼4.7 Hz, 12.0 Hz, 1H, H-6),
4.68 (dd, J¼2.1 Hz, 12.0 Hz, 1H, H-60), 4.41 (ddd, J¼2.1 Hz, 4.5 Hz,
9.8 Hz, 1H, H-5), 4.27 (dd, J¼3.5 Hz, 9.9 Hz, 1H, H-4), 3.48 (s, 3H,
(100 MHz, CDCl3)
d
¼193.5, 170.7, 169.8, 169.7, 101.0, 68.7, 68.6, 66.9,
OMe), 2.84 (s, 1H, OH). 13C NMR (100 MHz, CDCl3)
d¼166.9, 166.4,
62.4, 55.5, 47.2, 30.6, 20.8, 20.7. HRMS (ESI-TOF) m/z: [MþNa]þ
164.9, 133.5, 133.3, 130.2, 130.1, 130.0, 129.9, 129.8, 129.7, 129.3,
128.6,128.5,128.4, 98.5, 70.0, 69.8, 67.2, 64.4, 64.2, 55.7. HRMS (ESI-
TOF) m/z: [MþNa]þ Calcd for C28H26O9Na 529.1475; found
529.1475.
Calcd for C15H22O9SNa 401.0882; found 401.0879.
4.16. Methyl 2,4-di-thio-
a-D-mannopyranoside 6
Prepared from 3,6-di-O-acetyl-2,4-di-S-acetyl-
a-D-mannopyr-
4.12. For compound 20
anoside 25 according to the general deacetylation of thio-
containing carbohydrate derivatives procedure procedure, 44% to-
1H NMR (400 MHz, CDCl3)
d
¼8.17e7.32 (m, 15H, Phx3), 5.59 (dd,
tal yield. 1H NMR (400 MHz, CDCl3)
d
¼4.86 (s, 1H, H-1), 3.93e3.79
J¼3.2 Hz, 10.3 Hz, 1H, H-4), 5.30 (dd, J¼1.1 Hz, 3.6 Hz, 1H, H-2), 4.96
(s, 1H, H-1), 4.72 (dd, J¼2.3 Hz, 11.8 Hz, 1H, H-6), 4.59 (ddd,
J¼2.3 Hz, 4.9 Hz,10.3 Hz,1H, H-5), 4.52 (dd, J¼5.0 Hz,11.8 Hz,1H, H-
(m, 3H, H-3, H-6, H-60), 3.60e3.51 (m, 1H, H-5), 3.35 (ddd, J¼1.2 Hz,
4.5 Hz, 9.7 Hz, 1H, H-2), 3.31 (s, 3H, OMe), 3.03 (td, J¼8.3 Hz,
10.5 Hz, 1H, H-4), 2.78 (s, 2H, OH), 1.75 (d, J¼9.7 Hz, 1H, SH), 1.58 (d,
6), 4.45 (t, J¼3.3 Hz, 1H, H-3), 3.53 (s, 3H, OMe), 3.42 (s, 1H, OH). 13
C
J¼8.3 Hz, 1H, SH). 13C NMR (100 MHz, CDCl3)
¼102.5, 74.4, 70.3,
d
NMR (100 MHz, CDCl3)
d
¼166.4, 165.7, 165.3, 133.9, 133.8, 133.7,
62.8, 55.4, 45.6, 39.9. HRMS (ESI-TOF) m/z: [MþNa]þ Calcd for
133.3, 130.4, 130.1, 130.0, 129.9, 129.6, 129.5, 129.3, 128.8, 128.7,
128.6, 99.1, 70.5, 68.1, 67.5, 64.5, 63.8, 56.2. HRMS (ESI-TOF) m/z:
[MþNa]þ Calcd for C28H26O9Na 529.1475; found 529.1470.
C7H14O4S2Na 249.0231; found 249.0228.
4.17. Methyl 2,4-di-S-acetyl-3,6-di-O-acetyl-a-D-mannopyr-
anoside 25
4.13. Methyl 2,4,6-tri-O-benzoyl-3-S-acetyl-a-D-mannopyr-
anoside 21
Prepared from compound 23 according to the general synthesis
of triflate derivatives and general double parallel inversion pro-
cedure. The yield over two steps is 63%. 1H NMR (400 MHz, CDCl3)
To a solution of compound 20 (66 mg) in DCM (2 mL) was added
pyridine (68
(66
m
L) at ꢁ30 ꢀC. Trifluoromethanesulfonic anhydride
d
¼5.52 (dd, J¼4.4 Hz, 11.5 Hz, 1H), 4.83 (d, J¼1.3 Hz, 1H, H-1), 4.34
m
L) in DCM (0.5 mL) was added dropwise, and the mixture was
(dd, J¼5.2 Hz, 12.1 Hz, 1H, H-6), 4.25 (dd, J¼1.6 Hz, 4.4 Hz, 1H, H-2),
4.18 (dd, J¼2.1 Hz, 12.1 Hz, 1H, H-60), 3.99 (ddd, J¼2.0 Hz, 5.2 Hz,
11.2 Hz, 1H, H-5), 3.81 (t, J¼11.4 Hz, 1H, H-4), 3.40 (s, 3H, OMe), 2.39
warmed to ꢁ10 ꢀC and stirred for 4 h. The resulting mixture was
extracted and concentrated. The residue was dissolved in toluene
(1.5 mL) with the addition of TBASAc (20 equiv, 827 mg). After being
stirred at rt for 5 h, the mixture was extracted and concentrated.
The crude product was purified by flash chromatography with
solvent system petrol/ethyl acetate 8:1 giving compound 21
(s, 3H, SAc), 2.35 (s, 3H, SAc), 2.13 (s, 3H, OAc), 1.97 (s, 3H, OAc). 13
C
NMR (100 MHz, CDCl3)
63.6, 55.5, 47.8, 41.8, 30.8, 30.7, 20.9, 20.8. HRMS (ESI-TOF) m/z:
[MþNa]þ Calcd for C15H22O8S2Na 417.0654; found 417.0655.
d
¼193.7, 192.9, 170.9, 169.8, 101.1, 70.0, 67.2,