694
J. H. Zaidi et al. • Synthesis and Bioactivities of Naturally Occurring Anthraquinones
'H NM R (500 MHz, CDC13): d = 9.11 (s, 1H, 9-
H), 8.34 (s, 1H, 10-H), 7.78 (dd, J = 9.0, 1.8 Hz,
1H, 8-H), 7.65 (dd, J = 9.0, 9.0 Hz, 1H, 7-H), 7.35
(d, J = 9.0 Hz, 1H, 4-H), 7.26 (d, J = 9.0 Hz, 1H,
3-H), 7.01 (dd, J = 9.0, 1.8 Hz, 1H, 6-H), 5.45 (s,
2H, CH2), 5.34 (s, 2H, CH2), 4.42 (q, J = 7.5 Hz,
2H), 3.65 (s, 3H, CH3), 3.58 (s, 3H, CH 3), 1.40 (t,
J = 7.5 Hz, 3H). - MS (E l, 70 eV): m /z = 370. -
C21H 2, 0 6 (370.41): calcd. C 68.1, H 5.99; found C
68.11, H 5.95.
m /z = 400. - C23H 280 6 (400.48): calcd. C 68.98, H
7.05; found C 68.98, H 7.03.
1.8-Bis(m ethoxym ethoxy)-2-(ethoxyethoxy)m ethyl-
9, 10-anthraquinone (16) and l,5-bis(m ethoxy-
m ethoxy) -2-(ethoxyethoxy)methyl-9,10-
anthraquinone (25)
The anthraquinones 16 and 25 were obtained by
oxidation of the anthracenes 15 and 24, respec-
tively, using the procedure for the synthesis of
anthraquinones 13 and 22.
1,8-Bis(m ethoxym ethoxy)-2-
(ethoxyethoxy)methylanthracene (15)
1.8-Bis(m ethoxym ethoxy)-2-(ethoxyethoxy)m ethyl-
Ester 14 (370 mg, 1 mmol) was dissolved in TH F
and cooled to -1 0 °C. To this solution a 1 M solu-
tion of DIBAL in hexane (5 ml) was slowly added
dropwise and the reaction mixture stirred for 1 h.
A fter aqueous work-up, the crude product was dis-
solved in CH2C12, 50 mg of p-toluenesulphonic
acid (PPTS) and then ethyl vinyl ether (1 ml) was
added dropwise under stirring to the reaction mix-
9.10-anthraquinone (16)
Thick yellow liquid (qantitative yield).
-
IR
(neat): v = 2900, 1720, 1670, 1630, 1585 cm "1. -
lH NM R (500 MHz, CDC13): <3= 8.05 (dd, J = 8.0,
1.0 Hz, 1H, 5-H), 7.92 (d, J = 8.0 Hz, 1H, 4-H),
7.86 (dd, / = 8.0, 8.0 Hz, 1H, 6-H), 7.63 (d, J = 8.0
Hz, 1H, 3-H), 7.51 (dd, / = 8.0, 1.0 Hz, 1H, 7-H),
ture, monitoring the reaction by TLC. A fter com- 5.35 (s, 2H, CH2), 5.20 (s, 2H, CH2), 4.93 (s, 2H,
pletion within 45 min, the reaction was quenched
with aqueous N aH C 0 3 and worked up. The
solvent was evaporated and the residue applied to
a silica gel column and eluted with hexane-EtOAc
(98:2); yield 180 mg (75%) as a pale yellow li-
quid. - IR (neat): v = 2880, 1682, 1660, 1608, 1560
cm -1. - !H NM R (500 MHz, CDC13): <5 = 9.13 (s,
1H, 10-H), 8.36 (s, 1H, 9-H), 7.79 (dd, J = 8.5, 1.6
Hz, 1H, 5-H), 7.62 (dd, J = 8.5, 8.5 Hz, 1H, 6-H),
7.53 (d, J = 8.5 Hz, 1H, 4-H), 7.39 (d, J = 8.5 Hz,
1H, 3-H), 7.02 (dd, 1H, J = 8.5, 1.6 Hz, 7-H), 5.47
(s, 2H, CH 2), 5.29 (s, 2H, CH 2), 4.91 (s, 2H, CH 2),
CH2), 4.84-4.78 (m, 4H), 4.46 (q, 2H, J = 7.5 Hz,
OC7/2CH 3), 3.60 (s, 3H, CH3), 3.56 (s, 3H, C H 3),
1.22 (t, J = 7.5 Hz, 3H, CH 3). - MS (El, 70 eV):
m /z = 430. - C23H 260 8 (430.46): calcd. C 64.18, H
6.09; found C 64.10, H 6.11.
1,5-Bis (methoxym ethoxy)-2-(ethoxyethoxy)methyl-
9.10-anthraquinone (25)
Thick yellow liquid (quantitative yield). - IR
(neat): v = 2920, 2880, 1720, 1665, 1585 cm "1. -
!H NM R (500 MHz, CDC13): <5= 7.96 (dd, J = 8.0,
1.0 Hz, 1H, 8-H), 7.94 (d, J = 8.0 Hz, 1H, 4-H),
7.66 (dd, J = 8.0, 8.0 Hz, 1H, 7-H), 7.53 (d, J = 8.0
Hz, 1H, 3-H), 7.50 (dd, J = 8.0, 1.0 Hz, 1H, 6-H),
5.50 (s, 2H, CH2), 5.35 (s, 2H, CH2), 5.04 (s, 2H,
CH2), 4.84-4.78 (4H, m), 4.47 (q, J = 6.5 Hz, 2H,
O C //2CH3), 3.82 (s, 3H, CH3), 3.62 (s, 3H, CH 3),
1.27 (t, J = 6.5 Hz, 3H, CH3). - MS (El, 70 eV):
m /z = 430. - C23H 260 8 (430.46): calcd. C 64.18, H
6.09; found C 64.09, H 6.06.
4.68-4.61 (4H, m), 4.41 (q, J
= 7.0 Hz, 2H,
O C H 2C U 3), 3.76 (s, 3H, CH3), 3.59 (s, 3H, CH 3),
1.24 (t, J = 7.0 Hz, 3H, C H 3). - MS (E l, 70 eV):
m /z = 400. - C23H 280 6 (400.48): calcd. C 68.98, H
7.05; found C 68.91, H 7.00.
1,5-Bis(m ethoxym ethoxy)-2-
(ethoxyethoxy)methylanthracene (24)
24 was prepared from 23 in an analogous way
as described for 15 as pale yellow liquid (180 mg,
75%). - IR (neat): v = 2920, 2880, 1660,1630,1540
cm “1. - lH NM R (500 MHz, CDC13): 6 = 8.83 (s,
1H, 9-H), 8.64 (s, 1H, 10-H), 7.85 (dd, J =, 9.0, 1.7
Hz, 1H, 8-H), 7.67 (dd, J = 9.0, 9.0 Hz, 1H, 7-H),
7.36 (d, J = 9.0 Hz, 1H, 4-H), 7.25 (d, J = 9.0 Hz,
1H, 3-H), 7.03 (dd, J = 9.0, 1.7 Hz, 1H, 6-H) 5.46
(s, 2H, C H 2), 5.27 (s, 2H, C H 2), 4.95 (s, 2H, CH2),
(o-H ydroxyisochrysophanol (6) and
morindaparvin (7)
a>-Hydroxyisochrysophanol (6) and m orinda-
parvin (7) were obtained via deprotection of
anthraquinones 16 and 25 by stirring in m ethanol
(10 ml) containing five drops of freshly distilled
acetyl chloride for 1 h. The reaction was quenched
with 1 ml of triethylamine. Methanol was evapo-
rated and pure samples of w-hydroxyisochryso-
4.84-4.75 (m, 4H), 4.45 (q,
J = 7.5 Hz, 2H,
O C //2CH3), 3.72 (s, 3H, CH 3), 3.59 (s, 3H, C H 3),
1.24 (t, J = 7.5 Hz, 3H, CH 3). - MS (El, 70 eV):
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