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Helvetica Chimica Acta – Vol. 96 (2013)
Triphenylmethyl (3b,4a)-23-(Benzoyloxy)-3-hydroxyolean-12-en-28-oate (6). A soln. of hederagenin
(5; 500 mg, 1.06 mmol), TrCl (363 mg, 1.27 mmol), and DBU (0.26 ml, 1.70 mmol) in dry THF (15 ml)
was refluxed for 10 h. The solvent was evaporated and the residue dissolved in pyridine (8 ml) and
CH2Cl2 (12 ml), and then benzoyl chloride (0.17 ml, 1.48 mmol) was slowly added at 08. After stirring for
1 h, the reaction was quenched by addition of MeOH, the mixture concentrated, the residue taken up
with CH2Cl2, the CH2Cl2 phase washed with H2O and brine, dried (Na2SO4), and concentrated, and the
27
residue purified by CC SiO2, petroleum ether/AcOEt 12 :1: 6 (616 mg, 71%). White solid. [a]D ¼ þ16.7
(c ¼ 0.85, CHCl3). 1H-NMR (CDCl3, 600 MHz): 7.27 – 8.03 (m, 20 arom. H); 5.32 (t, J ¼ 3.3, HꢀC(12));
4.53 (d, J ¼ 11.3, 1 H, CH2(23)); 4.03 (d, J ¼ 11.3, 1 H, CH2(23)); 3.49 (dd, J ¼ 13.7, 4.4, HꢀC(3)); 2.89 (dd,
J ¼ 13.5, 4.0, HꢀC(18)); 1.13, 0.99, 0.95, 0.90, 0.83, 0.74 (s each, 3 H each, 6 Me). 13C-NMR (CDCl3,
150 MHz): 179.1 (C(28)); 166.8; 143.7 (C(13)); 137.7; 137.5; 136.5; 132.4; 130.1; 129.6; 129.1; 128.4; 122.3
(C(12)); 72.5 (C(3)); 66.8 (C(23)); 48.3; 47.9; 46.9; 42.4; 41.5; 39.2; 38.4; 36.9; 33.1; 31.8; 27.8; 26.7; 25.8;
24.3; 23.3; 17.9; 17.1; 15.7; 12.1. HR-ESI-MS: 841.4831 ([M þ Na]þ, C56H66NaO5þ ; calc. 841.4803).
Compounds 15 – 18: Typical Procedure. A mixture of 6 (100 mg, 0.11 mmol), trichloroacetimidate 7,
8, 9, or 10 (0.14 mmol, 1.2 equiv.), and powdered 4-ꢄ molecular sieves in dry CH2Cl2 (5 ml) was stirred
for 30 min at r.t. and then cooled to 08. Me3SiOSO2CF3 (15 ml, 0.09 mmol, 0.3 equiv.) was added slowly at
ꢀ 788. After 30 min stirring at ꢀ 788, the mixture was warmed up to r.t. within 30 min, and then cooled
again to 08. A soln. of 7 (122 mg, 0.17 mmol, 1.5 equiv.) in dry CH2Cl2 (5 ml) was injected slowly. The
mixture was stirred at 08 for 30 min, and then warmed up to r.t. within another 30 min. The reaction was
quenched by addition of Et3N and then the mixture filtered. The filtrate was concentrated and purified by
a CC SiO2, petroleum ether/AcOEt) to afford the products 15 – 18.
2,3,4,6-Tetra-O-benzoyl-b-d-glucopyranosyl (3b,4a)-23-(Benzoyloxy)-3-[(2,3,4,6-tetra-O-benzoyl-b-
d-glucopyranosyl)oxy]okan-12-en-28-oate (15): Yield 68%. [a]2D3 ¼ þ20.6 (c ¼ 1.01, CHCl3). 1H-NMR
(CDCl3, 600 MHz): 7.31 – 8.05 (m, 45 arom. H); 5.97 (t, J ¼ 9.7, 1 H, HꢀC(3’’)); 5.93 (d, J ¼ 8.3, HꢀC(1’’));
5.91 (t, J ¼ 9.6, HꢀC(3’)); 5.57 – 5.71 (m, HꢀC(2’), HꢀC(2’’), HꢀC(4’), HꢀC(4’’)); 5.27 (t, J ¼ 3.1,
HꢀC(12)); 4.85 (d, J ¼ 7.9, HꢀC(1’)); 4.61 (dd, J ¼ 11.9, 3.2, 1 H, CH2(6’)); 4.57 (dd, J ¼ 11.9, 6.9, 1 H,
CH2(6’)); 4.51 (dd, J ¼ 11.5, 2.8, 1 H, CH2(6’’)); 4.47 (dd, J ¼ 11.5, 5.0, 1 H, CH2(6’’)); 4.35 (d, J ¼ 11.3, 1 H,
CH2(23)); 4.27 – 4.31 (m, 2 H, HꢀC(5’’), CH2(23)); 4.15 (m, HꢀC(5’)); 3.69 (dd, J ¼ 11.7, 3.7, HꢀC(3));
3.19 (dd, J ¼ 13.7, 4.0, HꢀC(18)); 1.07, 0.97, 0.95, 0.91, 0.77, 0.73 (s each, 3 H each, 6 Me). 13C-NMR
(CDCl3, 150 MHz): 177.3 (C(28)); 165.9; 165.7; 165.4; 163.9; 163.4; 143.7 (C(13)); 138.3; 138.1; 137.8;
137.5; 136.5; 136.1; 133.5; 133.1; 132.9; 129.8; 129.6; 128.5; 128.1; 122.4 (C(12)); 105.4 (C(1’)); 96.7
(C(1’’)); 89.3 (C(3)); 78.3; 77.5; 71.9; 70.5; 70.1; 67.1; 66.9; 66.2; 65.8; 62.6; 55.9; 47.9; 46.9; 41.7; 39.2; 36.7;
33.3; 31.9; 27.8; 26.7; 25.8; 24.6; 17.6; 17.1; 15.6. HR-MALDI-MS: 1755.6883 ([M þ Na]þ, C105H104NaO2þ3
;
calc. 1755.6862).
2,3,4,6-Tetra-O-benzoyl-b-d-glucopyranosyl (3b,4a)-23-(Benzoyloxy)-3-[(2,3,4-tri-O-benzoyl-b-d-
xylopyranosyl)oxy]olean-12-en-28-oate (16): Yield 62%. [a]2D3 ¼ þ23.1 (c ¼ 0.96, CHCl3). 1H-NMR
(CDCl3, 600 MHz): 7.33 – 8.03 (m, 40 arom. H); 5.97 (t, J ¼ 9.6, HꢀC(3’’)); 5.93 (d, J ¼ 8.7, HꢀC(1’’)); 5.78
(t, J ¼ 8.5, HꢀC(3’)); 5.71 – 5.74 (m, HꢀC(2’’), HꢀC(4’’)); 5.44 (dd, J ¼ 8.2, 6.4, HꢀC(2’)); 5.30 (dt, J ¼ 8.7,
4.6, HꢀC(4’)); 5.27 (t, J ¼ 3.7, HꢀC(12)); 4.81 (d, J ¼ 6.4, HꢀC(1’)); 4.53 (dd, J ¼ 11.5, 2.8, 1 H, CH2(6’’));
4.47 (dd, J ¼ 11.0, 5.0, 1 H, CH2(6’’)); 4.43 (dd, J ¼ 11.9, 4.6, 1 H, CH2(5’); 4.37 (d, J ¼ 11.5, 1 H, CH2(23));
4.29 (d, J ¼ 11.5, 1 H, CH2(23)); 4.26 (m, HꢀC(5’’)); 3.67 (dd, J ¼ 13.7, 3.7, HꢀC(3)); 3.61 (dd, J ¼ 11.9, 7.8,
1 H, CH2(5’)); 3.13 (dd, J ¼ 14.3, 4.0, HꢀC(18)); 1.05, 0.97, 0.94, 0.89, 0.76, 0.73 (s each, 3 H each, 6 Me).
13C-NMR (CDCl3, 150 MHz): 177.5 (C(28)); 165.9; 165.6; 165.3; 163.9; 163.2; 143.6 (C(13)); 138.7; 138.0;
137.6; 136.4; 136.1; 133.5; 132.7; 129.8; 129.5; 128.3; 128.1; 122.5 (C(12); 104.3 (C(1’)); 96.7 (C(1’’)); 89.5
(C(3)); 77.9; 77.1; 70.8; 70.5; 69.9; 67.1; 66.3; 65.7; 62.6; 56.0; 47.7; 46.5; 42.3; 39.1; 36.7; 33.5; 31.9; 27.8;
26.7; 25.9; 24.7; 17.6; 15.3. HR-MALDI-MS: 1621.6509 ([M þ Na]þ, C97H98NaO2þ1 ; calc. 1621.6493).
2,3,4,6-Tetra-O-benzoyl-b-d-glucopyranosyl (3b,4a)-23-Benzoyloxy)-3-[(2,3,4-tri-O-benzoyl-a-l-
1
arabinopyranosyl)oxy]olean-12-en-28-oate (17): Yield 60%. [a]2D3 ¼ þ30.6 (c ¼ 1.03, CHCl3). H-NMR
(CDCl3, 600 MHz): 7.25 – 8.07 (m, 40 arom. H); 5.96 (t, J ¼ 9.7, HꢀC(3’’)); 5.93 (d, J ¼ 8.3, HꢀC(1’’));
5.67 – 5.78 (m, HꢀC(2’), HꢀC(3’), HꢀC(2’’), HꢀC(4’’)); 5.58 (dd, J ¼ 8.8, 3.4, HꢀC(4’)); 5.27 (t, J ¼ 3.3,
HꢀC(12)); 4.76 (d, J ¼ 6.5, HꢀC(1’)); 4.43 – 4.56 (m, 3 H, CH2(5’), CH2(6’’), CH2(6’’)); 4.36 (d, J ¼ 11.7,
1 H, CH2(23)); 4.27 (m, HꢀC(5’’)); 4.23 (d, J ¼ 11.5, 1 H, CH2(23)); 3.85 (dd, J ¼ 11.6, 6.3, 1 H, CH2(5’));
3.61 (dd, J ¼ 14.3, 3.7, HꢀC(3)); 3.11 (dd, J ¼ 13.9, 4.1, HꢀC(18)); 1.01, 0.95, 0.93, 0.89, 0.75, 0.73 (s each,