The Journal of Organic Chemistry
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4.06−3.75 (2 × AB, 4H), 3.98 (bd, J = 2.8 Hz, 1H), 3.90 (bd, J = 2.8
Hz, 1H), 3.80−3.55 (6H), 3.16 (dd, J = 2.8, 10.8 Hz, 1H), 2.86 (dd, J
= 8.0, 10.4 Hz, 1H). 13C NMR (100 MHz, CDCl3), significant signals
of prevalent pyranose anomers at δ 139.6, 139.2, 137.7 (×2) (C ipso),
129.2−127.1 (aromatic CH), 96.2 and 91.7 (C-1 β and α), 73.6 (×2),
70.4, 69.7, 69.0, 68.8, 68.2, 67.9, 65.1, 60.2, 54.7, 54.5. MALDI-MS [M
+ Na]+ calcd for (C20H25NO5), 382.16; found, 382.35. Anal. Calcd for
C20H25 NO5: C, 66.83; H, 7.01. Found: C, 66.75; H, 7.00.
Allyl 2,3,6-Tri-O-benzyl-α-D-galacto-pyranoside (40).19 Flash
chromatography (eluent: ethyl acetate/hexane 1:3) afforded 40 (143
mg, 55%) as an oil. 1H NMR (500 MHz, CDCl3) δ 7.45−7.15
(aromatic H), 5.95−5.80 (m, 1H), 5.26 (bd, J = 17.0 Hz, 1H), 5.14
(bd, J = 10.5 Hz, 1H), 4.82 (d, J = 3.0 Hz, 1H), 4.75−4.48 (3 × AB,
6H), 4.11 (bdd, J = 5.0 , 12.5 Hz, 1H), 4.02 (bs, 1H), 3.98 (bdd, J =
6.5, 12.5 Hz, 1H), 3.91 (bt, J = 5.5 Hz, 1H), 3.88−3.80 (overlapped
signals, 2H), 3.70−3.60 (m, 2H), 2.52 (bs, 1H). 13C NMR (100 MHz,
CDCl3) δ 138.3, 138.1, and 137.9 (aromatic C), 133.7 (−CHCH2),
128.3−127.5 (aromatic CH), 117.9 (−CHCH2), 96.0 (C-1), 77.6,
75.6, 73.4, 73.2, 72.7, 69.5, 68.4, 68.2, 67.9. Anal. Calcd for C30H34O6:
C, 73.45; H, 6.99. Found: C, 73.55; H, 6.95.
4-O-Benzyl-α/β-D-digitoxo-pyranose (α/β ca. 1) (34). Flash
chromatography (eluent: ethyl acetate/hexane 3:1) afforded 34 (116
mg, 81%) as an oil. 1H NMR (400 MHz, CDCl3) δ 7.40−7.20
(aromatic H), 5.22 (d, J = 9.6 Hz, 1H), 5.12 (m, 1H), 4.66−4.51 (2 ×
AB, 4H), 4.30−4.10 (overlapped signals, 3H), 3.87 (m, 1H), 3.23
(1H), 3.12 (dd, J = 2.8, 9.6 Hz, 2H), 2.60 (1H), 2.20 (m, 2H), 1.79
(m, 1H), 1.59 (m, 1H), 1.30 and 1.28 (2d, J = 6.4 Hz, 6H,). 13C NMR
(100 MHz, CDCl3) δ 137.3 (aromatic C), 128.4−127.9 (aromatic
CH), 91.7 and 91.5 (C-1 α and β), 80.2, 80.0, 71.6, 71.5, 68.1, 65.2,
64.5. 61.5, 18.1, and 18.0. MALDI-MS [M + Na]+ calcd for
(C13H18O4), 261.12; found, 261.00. Anal. Calcd for C13H18O4: C,
65.53; H, 7.61. Found: C, 65.45; H, 7.65.
Methyl 2,3,4,6-Tetra-O-benzyl-α-D-gluco-pyranoside (41).23 Flash
chromatography (eluent: hexane/ethyl acetate from 9:1 to 1:1)
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afforded 41 (236 mg, 71%) as an oil. H NMR (400 MHz, CDCl3) δ
7.50−7.20 (aromatic H), 5.00−4.52 (4 × AB, 8H), 4.70 (d, J = 3.6 Hz,
1H), 4.06 (bt, J = 9.6 Hz, 1H), 3.85−3.73 (overlapped signals, 2H),
3.72−3.65 (overlapped signals, 2H), 3.63 (d, J = 3.6, 9.6 Hz, 1H), 3.44
(s, 3H). 13C NMR (125 MHz, CDCl3) δ 138.7, 138.1, 138.0, 137.8
(aromatic C), 128.4−127.4 (aromatic CH), 98.0 (C-1), 82.0, 79.7,
77.5, 75.6, 74.9, 73.3, 73.2, 69.9, 68.4, 55.0. Anal. Calcd for C35H38O6:
C, 75.79; H, 6.91. Found: C, 75.65; H, 7.00.
Methyl 2,6-Di-O-benzyl-α-D-gluco-pyranoside (35).4a,22 Flash
chromatography (eluent: hexane/ethyl acetate from 7:3 to 1:1)
Methyl 2,3,4,6-Tetra-O-benzyl-α-D-manno-pyranoside (42).24
Flash chromatography (eluent: hexane/ethyl acetate from 85:15 to
4:1) afforded 42 (256 mg, 79%) as an oil. 1H NMR (400 MHz,
CDCl3) δ 7.55−7.20 (aromatic H), 5.05−4.65 (4 × AB, 8H), 4.93 (d,
J = 2.0 Hz, 1H), 4.14 (t, J = 9.6 Hz, 1H), 4.04 (dd, J = 3.2, 9.6 Hz,
1H), 3.96 (dd, J = 2.0, 3.5 Hz, 1H), 3.95−3.87 (3H), 3.48 (s, 3H). 13C
NMR (125 MHz, CDCl3) δ 138.5 (×2), 138.3, 138.2 (aromatic C),
128.4−127.3 (aromatic CH), 98.9 (C-1), 80.2, 75.0, 74.8, 74.5, 73.3,
72.5, 72.0, 71.6, 69.2, 54.7. Anal. Calcd for C35H38O6: C, 75.79; H,
6.91. Found: C, 75.85; H, 6.95.
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afforded 35 (159 mg, 56%) as an oil. H NMR (400 MHz, CDCl3) δ
7.40−7.20 (aromatic CH), 4.77 (d, J = 3.6 Hz, 1H), 4.75−4.55 (2 ×
AB, 4H), 3.93 (t, J = 9.6 Hz, 1H), 3.75−3.70 (overlapped signals, 3H),
3.57 (bt, J = 9.6 Hz, 1H), 3.38 (dd, J = 3.6, 9.6 Hz, 1H), 3.34 (s, 3H).
13C NMR (100 MHz, CDCl3) δ 137.9 (C ipso), 128.3−127.4
(aromatic CH), 97.6 (C-1), 79.0, 73.3, 72.9 (×2), 70.5, 69.9, 69.2,
55.0. Anal. Calcd for C21H26O6: C, 67.36; H, 7.00. Found: C, 67.25; H,
7.05.
Methyl 3,6-Di-O-benzyl-α-D-gluco-pyranoside (36). Flash chro-
matography (eluent: hexane/ethyl acetate from 7:3 to 1:1) afforded 36
Methyl 3-O-Allyl-4,6-benzylidene-α-D-manno-pyranoside (43).25
Flash chromatography (eluent: hexane/ethyl acetate from 8:2 to 7:3)
1
(40 mg, 14%) as an oil. H NMR (400 MHz, CDCl3) δ 7.40−7.20
(aromatic CH), 4.79 (d, J = 3.6 Hz, 1H), 5.00−4.57 (2 × AB, 4H),
3.75−3.55 (ovelapped signals, 6H), 3.45 (s, 3H), 2.57 (bs, 1H), 2.25
(d, J = 8.4 Hz, 1H). 13C NMR (100 MHz, CDCl3) δ 138.5 and 137.8
(C ipso), 128.5−127.5 (aromatic CH), 99.4 (C-1), 82.6, 74.9, 73.5,
72.4, 70.8, 70.0, 69.6, 55.2. Anal. Calcd for C21H26O6: C, 67.36; H,
7.00. Found: C, 67.35; H, 7.10.
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afforded 43 (174 mg, 90%) as an oil. H NMR (400 MHz, CDCl3) δ
7.55−7.30 (aromatic H), 6.00−5.75 (m, 2H), 5.60 (s, 1H), 5.32 (bd, J
= 17.2 Hz, 1H), 5.20 (bd, J = 10.4 Hz, 1H), 4.79 (d, J = 0.8 Hz, 1H),
4.40−4.16 (overlapped signals, 3H), 4.10−4.03 (overlapped signals,
2H), 3.90−3.79 (overlapped signals, 3H), 3.40 (s, 3H), 2.78 (s, 1H).
13C NMR (100 MHz, CDCl3) δ 137.5 (aromatic C), 134.5 (−CH
CH2), 128.9, 128.2, 126.0, 117.4 (−CHCH2), 101.5, 101.0, 78.8,
75.1, 71.8, 69.9, 68.8, 63.1, 54.9. Anal. Calcd for C17H22O6: C, 63.34;
H, 6.88. Found: C, 63.45; H, 6.80.
3,6-Di-O-benzyl-D-galactal (37).15 Flash chromatography (eluent:
hexane/ethyl acetate from 3:1 to 1:1) afforded 37 (113 mg, 64%) as an
oil. 1H NMR (400 MHz, CDCl3) δ 7.45−7.25 (aromatic H), 6.45 (bd,
J = 5.6 Hz, 1H), 4.74 (bd, J = 5.6 Hz, 1H), 4.70−4.55 (2 × AB, 4H),
4.22 (m, 1H), 4.13 (m, 1H), 4.05 (bt, J = 6.0 Hz, 1H), 3.85−3.75 (m,
2H), 2.64 (1H). 13C NMR (125 MHz, CDCl3) δ 144.9 (C-1), 137.7
and 137.5 (aromatic C), 128.4−127.7 (aromatic CH), 99.4 (C-2),
75.3, 73.6, 70.6, 70.3, 69.2, 62.9. Anal. Calcd for C20H22O4: C, 73.60;
H, 7.00. Found: C, 73.50; H, 7.05.
Methyl 3-O-Allyl-β-L-arabino-pyranoside (44). Flash chromatog-
raphy (eluent: ethyl acetate) afforded 44 (127 mg, 78%) as a foam.
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1
[α]D +194 (c 1.3, CHCl3). H NMR (400 MHz, CDCl3) δ 6.00−
5.75 (m, 2H), 5.29 (bd, J = 17.2 Hz, 1H), 5.18 (bd, J = 10.0 Hz, 1H),
4.75 (d, J = 3.6 Hz, 1H), 4.20−4.05 (m, 2H), 3.99 (m, 1H), 3.90 (m,
1H), 3.71 (d, J = 2.0 Hz, 2H), 3.56 (dd, J = 3.6, 9.6 Hz, 1H), 3.39 (s,
3H), 2.79 (s, 1H), 2.55 (d, 1H). 13C NMR (100 MHz, CDCl3) δ 134.4
(−CHCH2), 117.8 (−CHCH2), 99.5 (C-1), 77.3, 70.8, 68.1, 66.6,
61.7, 55.4. MALDI-MS [M + Na]+ calcd for (C9H16O5), 227.10;
found, 227.05. Anal. Calcd for C9H16O5: C, 52.93; H, 7.90. Found: C,
53.05; H, 7.85.
DL-1,3,4-Tri-O-benzyl-myo-inositol (38).4d Flash chromatography
(eluent: from ethyl acetate/hexane 3:2 to ethyl acetate) afforded 38
(204 mg, 40%) as a white solid. 1H NMR (400 MHz, CDCl3) δ 7.50−
7.30 (aromatic H), 5.01−4.70 (3 × AB, 6H), 4.27 (bs, 1H), 4.02 (t, J =
10.0 Hz, 1H), 3.88 (t, J = 10.0 Hz, 1H), 3.50−3.40 (overlapped
signals, 2H), 3.26 (dd, J = 2.0, 9.5 Hz, 1H). 13C NMR (100 Hz,
CDCl3), δ 138.6, 137.7, 137.6 (aromatic C), 128.6−127.6 (aromatic
CH), 80.4, 79.6, 79.0, 75.4, 74.2, 72.4, 72.2, 71.9, 66.9. Anal. Calcd for
C27H30O6: C, 71.98; H, 6.71. Found: C, 72.05; H, 6.70.
Methyl 3-O-Allyl-α-D-manno-pyranoside (45).12b,26 Flash chroma-
tography (eluent: ethyl acetate/methanol from 95:5 to 9:1) afforded
45 (137 mg, 65%) as an oil. 1H NMR (400 MHz, CDCl3) δ 6.00−5.90
(m, 1H), 5.32 (bd, J = 17.2 Hz, 1H), 5.21 (bd, J = 17.2 Hz, 1H), 4.74
(bs, 1H), 4.25−4.10 (m, 2H), 4.02−3.90 (overlapped signals, 3H),
3.77 (bd, J = 12.0 Hz, 1H), 3.59 (dd, J = 3.2, 9.6 Hz, 1H), 3.51 (m,
Benzyl 3,6-Di-O-benzyl-β-D-manno-pyranoside (39). Flash chro-
matography (eluent: ethyl acetate/hexane 1:1) afforded 39 (179 mg,
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62%) a solid. [α]D −76 (c 1.7, CHCl3). 1H NMR (500 MHz,
1
1H), 3.34 (s, 3H, −OCH3). H NMR (100 MHz, CDCl3) δ 134.4
CDCl3) δ 7.50−7.20 (aromatic H), 4.98−4.60 (3 × AB, 6H, 3 ×
−CH2Ph), 4.47 (s, 1H, H-1), 4.11 (bs, 1H, H-2), 4.11 (bt, J = 9.5 Hz,
1H, H-4), 3.89 (dd, J = 3.5, 11.0 Hz, 1H, H-6a), 3.80 (dd, J = 4.4, 11.0
Hz, 1H, H-6b), 3.43 (m, 1H, H-5), 3.34 (dd, J = 2.5, 9.5 Hz, 1H, H-3),
2.87 and 2.61 (2H, 2s, OH-2 and OH-4). 13C NMR (125 MHz,
CDCl3) δ 137.9, 137.6, and 136.7 (ipso C), 128.4−127.5 (aromatic
CH), 98.0 (C-1), 80.8, 74.7, 73.5, 71.1, 70.3, 70.2, 67.7, 67.6. MALDI-
MS [M + Na]+ calcd for (C27H30O6), 473.19; found, 473.30. Anal.
Calcd for C27H30O6: C, 71.98; H, 6.71. Found: C, 72.10; H, 6.65.
(−CHCH2), 118.0 (−CHCH2), 100.7 (C-1), 79.0, 72.2, 70.9,
67.9, 64.7, 60.9, 54.8. Anal. Calcd for C12H20O6: C, 55.37; H, 7.74.
Found: C, 55.25; H, 7.80.
Allyl 3-O-Allyl-β-D-manno-pyranoside (46). Flash chromatography
(eluent: ethyl acetate/methanol from 9:1 to 6:1) afforded 46 (140 mg,
25
1
61%) as an oil. [α]D −68 (c 1.3, CHCl3). H NMR (400 MHz,
CDCl3) δ 6.00−5.75 (m, 2H), 5.35−5.10 (overlapped signals, 4H),
4.47 (s, 1H), 4.40−4.05 (overlapped signals, 4H), 4.06 (bs, 1H), 3.96
(bt, J = 9.6 Hz, 1H), 3.90−3.80 (m, 2H), 3.31 (dd, J = 2.8, 9.6 Hz,
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dx.doi.org/10.1021/jo402399n | J. Org. Chem. 2014, 79, 213−222