G. Varró et al.
OCH2CH2O), 3.83 (s, 3H, OCH3), 3.53–3.45 (m, 1H, 4a-
H), 2.95 (td, J = 12.3, 3.3 Hz, 1H, 12b-H), 2.11 (s, 3H,
COCH3), 2.04 (s, 3H, COCH3), 1.95 (s, 3H, COCH3), 1.78
(ddd, J = 14.4, 12.9, 2.4 Hz, 1H, 1-Hb) ppm (the sign of 1-
Ha is covered by that of DMSO-d6); 13C NMR (75 MHz,
DMSO-d6): d = 20.4 (COCH3), 20.7 (COCH3), 20.9
(COCH3), 26.0 (1-C), 35.3 (12b-C), 51.6 (4a-C), 55.7
(OCH3), 63.0 (OCH2CH2O), 63.1 (OCH2CH2O), 66.6 (3-
C), 68.1 (2-C), 70.5 (4-C), 99.5 (12-C), 111.0 (6a-C), 131.9
(7a-C), 134.1 (12a-C), 144.6 (7-C), 150.6 (11a-C), 162.5
(6-C), 169.1 (COCH3), 169.3 (COCH3), 169.9 (COCH3)
132.2 (12a-C), 133.7 (4-CBz), 148.2 (7-C), 152.6 (11a-C),
164.9 (6-C), 169.2 (COPh), 170.1 (COCH3), 170.3
ꢀ
(COCH3) ppm; IR (KBr): m = 3446, 2930, 1753, 1731,
1683, 1652, 1448, 1362, 1270, 1239, 1157, 1069, 1028,
803, 711 cm-1
.
(2)-7-Hydroxy-6-oxo-1,2,3,4,4a,9,10,12b-octahydro[1,4]-
dioxino[2,3-j]phenanthridine-2,3,4-triyl triacetate [(2)-54,
C21H23NO10] Yield: 55%; white solid; m.p.: 154–156 °C;
Rf = 0.85 (hexane/EtOAc, 1:2); 1H NMR (300 MHz,
CDCl3): d = 12.54 (s, 1H, OH), 6.25 (s, 1H, 12-H), 5.95 (s,
1H, NH), 5.44 (t, J = 3.0 Hz, 1H, 3-H), 5.20–5.16 (m, 2H,
2-H and 4-H), 4.32 (s, 4H, OCH2CH2O), 3.76 (dd,
J = 12.6, 11.1 Hz, 1H, 4a-H), 3.10 (td, J = 13.2, 3.3 Hz,
1H, 12b-H), 2.43 (dt, J = 14.4, 2.7 Hz, 1H, 1-Ha), 2.13 (s,
3H, COCH3), 2.09 (s, 3H, COCH3), 2.08 (s, 3H, COCH3),
1.90 (ddd, J = 14.4, 12.6, 2.7 Hz, 1H, 1-Hb) ppm; 13C
NMR (75 MHz, CDCl3): d = 20.7 (COCH3), 20.8
(COCH3), 21.0 (COCH3), 26.4 (1-C), 34.1 (12b-C), 52.8
(4a-C), 64.1 (OCH2CH2O), 64.8 (OCH2CH2O), 67.3 (3-C),
68.5 (2-C), 71.8 (4-C), 103.7 (12-C), 104.5 (6a-C), 131.1
(7a-C), 132.2 (12a-C), 148.2 (7-C), 152.6 (11a-C), 169.1
(6-C), 169.3 (COCH3), 170.1 (COCH3), 170.3 (COCH3)
ꢀ
ppm; IR (KBr): m = 3195, 3091, 2939, 1752, 1667, 1597,
1494, 1451, 1370, 1330, 1251, 1157, 1128, 1060, 1028,
799 cm-1; [a]2D2 = - 135.5° (c = 0.5, CHCl3).
General procedure for the selective
demethylation
To a solution of 0.18 g ( )-45/( )-46 (0.35 mmol) or
0.16 g (-)-52 (0.35 mmol) and 57.3 mg potassium iodide
(0.35 mmol) in 16 cm3 anhydrous acetonitrile, 48.7 mg
chlorotrimethylsilane (0.45 mmol) in 3.1 cm3 anhydrous
acetonitrile was added. The reaction mixture was heated to
60 °C and stirred for 4 h. Then, it was cooled to 0 °C and
26 cm3 water was added dropwise to quench the reaction.
After extraction with ethyl acetate (4 9 26 cm3), the
combined organic layer was washed with brine, dried over
Na2SO4, and the solvent was evaporated in vacuo. The
residue was purified by preparative TLC (EtOAc/heptane,
1:1) to give ( )-47 or (-)-54. Compound ( )-46, as well
as the by-products ( )-48 and ( )-49, was isolated from
the crude product obtained by the conversion of ( )-45/
( )-46.
ꢀ
ppm; IR (KBr): m = 3337, 2937, 1752, 1652, 1586, 1447,
1370, 1246, 1225, 1125, 1056, 1035, 858 cm-1; [a]D22
- 58.0° (c = 0.5, CHCl3).
=
(–)-2-Benzoyloxy-11-methoxy-6-oxo-1,2,3,4,4a,8,9,12b-oc-
tahydro[1,4]dioxino[2,3-i]phenanthridine-3,4-diyl diacetate
[(–)-46, C27H27NO10] Yield: 18%; white solid (fluffy);
m.p.: 237–238 °C; Rf = 0.51 (hexane/EtOAc, 1:2); 1H
NMR (300 MHz, CDCl3): d = 8.06 (dd, J = 8.1, 0.9 Hz,
2H, 2-HBz and 6-HBz), 7.60 (tt, J = 7.5, 1.2 Hz, 1H, 4-
HBz), 7.47 (t, J = 7.5 Hz, 2H, 3-HBz and 5-HBz), 7.08 (s,
1H, 12-HAr), 6.37 (s, 1H, NH), 5.59 (t, J = 3.0 Hz, 1H, 3-
H), 5.45 (q, J = 3.0 Hz, 1H, 2-H), 5.36 (dd, J = 10.8,
3.0 Hz, 1H, 4-H), 4.54–4.50 (m, 1H, OHCHCH2O), 4.39–
4.23 (m, 3H, OHCHCH2O), 3.92 (s, 3H, OCH3), 3.77 (dd,
J = 12.0, 11.4 Hz, 1H, 4a-H), 3.19 (td, J = 12.0, 3.0 Hz,
1H, 12b-H), 2.64 (dt, J = 12.6, 3.0 Hz, 1H, 1-Ha), 2.11 (s,
6H, 2 9 COCH3), 2.07–1.97 (m, 1H, 1-Hb) ppm; 13C
NMR (75 MHz, CDCl3): d = 20.7 (COCH3), 20.8
(COCH3), 27.0 (1-C), 35.5 (12b-C), 52.1 (4a-C), 56.2
(OCH3), 63.9 (OCH2CH2O), 64.6 (OCH2CH2O), 67.7 (2-
C), 69.2 (4-C), 71.5 (3-C), 99.2 (6a-C), 110.6 (12-C), 128.7
(3-CBz and 5-CBz), 129.0 (1-CBz), 129.8 (2-CBz and 6-CBz),
132.5 (10a-C), 133.7 (4-CBz), 134.2 (12a-C), 145.5 (6b-C),
151.7 (11-C), 165.0 (6-C), 165.1 (COPh), 169.2 (COCH3),
(–)-2-Benzoyloxy-7-hydroxy-6-oxo-1,2,3,4,4a,9,10,12b-oc-
tahydro[1,4]dioxino[2,3-j]phenanthridine-3,4-diyl diacetate
[(–)-47, C26H25NO10] Yield: 20%; white solid; m.p.: 201–
1
204 °C; H NMR (300 MHz, CDCl3): d = 12.52 (s, 1H,
OH), 8.03 (dd, J = 7.8, 1.2 Hz, 2H, 2-HBz and 6-HBz), 7.59
(tt, J = 7.5, 1.2 Hz, 1H, 4-HBz), 7.46 (t, J = 7.5 Hz, 2H, 3-
H
Bz and 5-HBz), 6.27 (s, 1H, 12-H), 6.10 (s, 1H, NH), 5.60
(t, J = 3.0 Hz, 1H, 3-H), 5.43 (q, J = 3.0 Hz, 1H, 2-H),
5.33 (dd, J = 10.8, 2.7 Hz, 1H, 4-H), 4.31 (s, 4H, OCH2-
CH2O), 3.85 (dd, J = 12.3, 11.1 Hz, 1H, 4a-H), 3.20 (td,
J = 12.9, 3.3 Hz, 1H, 12b-H), 2.60 (dt, J = 14.7, 2.7 Hz,
1H, 1-Ha), 2.12 (s, 3H, COCH3), 2.11 (s, 3H, COCH3),
2.01 (ddd, J = 14.7, 12.6, 2.4 Hz, 1H, 1-Hb) ppm; 13C
NMR (75 MHz, CDCl3): d = 20.7 (COCH3), 20.8
(COCH3), 26.5 (1-C), 34.3 (12b-C), 52.8 (4a-C), 64.1
(OCH2CH2O), 64.8 (OCH2CH2O), 67.5 (3-C), 69.1 (2-C),
71.9 (4-C), 103.7 (12-C), 104.5 (6a-C), 128.6 (3-CBz and 5-
CBz), 129.1 (1-CBz), 129.8 (2-CBz and 6-CBz), 131.1 (7a-C),
ꢀ
170.4 (COCH3) ppm; IR (KBr): m = 3179, 3078, 2935,
1753, 1723, 1668, 1598, 1495, 1451, 1369, 1330, 1269,
1238, 1137, 1097, 1060, 715 cm-1
.
123