Synthesis and cytotoxicity of dihydroartemisinin ethers containing cyanoarylmethyl group

Article abstract of DOI:10.1016/S0968-0896(02)00538-2

A new type of ether of dihydroartemisinin containing cyano and aryl groups was prepared and tested for cytotoxicity to A549, P388, L1210 and HT29 cells using the MTT assay. 12k and 12l were the most cytotoxic compounds. 13 lacking the peroxy group showed a 1000-fold less potency than 12l. Similarly, the inactive compound 14 indicated that the position of cyano groups was also important. Flow cytometry data showed that the compounds caused an accumulation of P388 cells in the G₁-phase of the cell cycle.

Full text of DOI:10.1016/S0968-0896(02)00538-2

Bioorganic & Medicinal Chemistry 11 (2003) 977–984
Synthesis and Cytotoxicity of Dihydroartemisinin Ethers
Containing Cyanoarylmethyl Group
Ying Li,a,* Jin-Ming Wu,a Feng Shan,a Guang-Shao Wu,a Jian Ding,b
Dong Xiao,b Jia-Xian Han,b Ghanem Atassi,c Stephane Leonce,c
Daniel-Henri Caignardd and Pierre Renardd
aDepartment of Synthetic Chemistry, Shanghai Institute of Materia Medica,
Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
bDepartment of pharmacology, Shanghai Institute of Materia Medica,
Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
cInstitut de Recherche Servier, Suresnes, France
dADIR ET COMPAGNIE, Courbevoie, France
Received 15 August 2002; accepted 16 October2002
Abstract—A new type of ether of dihydroartemisinin containing cyano and aryl groups was prepared and tested for cytotoxicity to
A549, P388, L1210 and HT29 cells using the MTT assay. 12k and 12l were the most cytotoxic compounds. 13 lacking the peroxy group
showed a 1000-fold less potency than 12l. Similarly, the inactive compound 14 indicated that the position of cyano groups was also
important. Flow cytometry data showed that the compounds caused an accumulation of P388 cells in the G1-phase of the cell cycle.
# 2002 Elsevier Science Ltd. All rights reserved.
Introduction
flavones and other terpenoids) showed cytotoxic prop-
erties at varying concentrations against L 1210, P 388, A
549, HT 29, MCF 7 and KB in vitro.2,4,9
Traditional Chinese medicine Qinghao (Artemisia annua
L.) was recorded as a versatile remedy for malaria, der-
matitis and otherdiseases in many Chinese ancient
medical books. Based on these clinical experiences,
Chinese scientists have developed artemisinin and its
derivatives (artemisinin 1, dihydroartemisinin 2, arte-
mether 3a and artesunate 3b) as a totally new type of
antimalarial drugs since 1970s. Up to now, these drugs
have been used in the clinic all overthe wolrd. Their
quick onset, powerful effect and good toleration may be
attributed to the 1,2,4-trioxane moieties in their mol-
ecules. A number of researchers have been focusing
theirattention on othercomponents of the plant, arte-
misinin derivatives/analogues and their bioactivities.1
More than 20 research papers reporting the cytotoxicity
of artemisinin family were recently published.2ꢀ21
Artemisinin and related compounds were tested against
Ehrlich Ascites tumour cells, on which artemisinin,
artemether, arteether and artesunate exhibited moderate
cytotoxicity (IC50 12.2–29.8 mM), artemisitene 6 was
slightly more active (IC50 6.8 mM), and a dimerof
dihydroartemisinin 7a was the most potent (IC50
1.4mM). It was found the nonsymmetric dimer 7a was
more cytotoxic than the symmetric dimer 7b due to their
slight different stereochemistry.5ꢀ7 Otheratremisinin
dimers, trimers and tetramers and their cytotoxicities
was reported recently.8
The antitumor effect of artesunate was tested in vitro and
in vivo in China.10ꢀ12 It was shown to be cytotoxic forsix
cell lines (IC50 1ꢁ100 mg/mL) and displayed antitumor
effects on human nasopharyngeal cancer (CNE2, SUNE-
1) and human livercancer(BEL-7402) grafted in nude
Some natural components of A. annua (such as artemi-
sinin, arteannuin-B 4, artemisinic acid 5, artemisitene 6,
mice. Recently artesunate has been analyzed for its anti-
13
tumoractivity against 55 cell lines.
colon cancercell lines were the most sensitive lines, and
no cross resistance against CEM leukemia sub-lines
Leukemia and
*Corresponding author at: 294 Taiyuan Road, Shanghai 200031,
China. Tel.:+86-21-6431-1833; fax:+86-21-6437-0269; e-mail: yli@
mail.shnc.ac.cn
0968-0896/03/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S0968-0896(02)00538-2

978
Y. Li et al. / Bioorg. Med. Chem. 11 (2003) 977–984
Chart 1.
which are resistant to either doxorubicin, vincristine,
methotrexate or hydroxyurea were observed.
pharmacological properties. They showed lower anti-
malarial activity than artemether but stronger anti-
tumoractivity in vitro. The most active compound was
10 (R=p-COOCH3, IC50=1.91, 0.33, 0.02 mM against
KB, HCT-8, A 2780 cell lines, respectively).19,20 There-
after, we noted that artemisinin derivatives 11 and 12a
were so quite different in their antitumor activity. 12a
with a phenyl group was much more active than 11.
This finding led us to explore the structure–activity
relationship of this kind of derivatives. Herein we report
synthesis and preliminary biological evaluation of 12
and related compounds (Charts 2 and 3). The brief
report has been published in 2001.
Lai’s group found that dihydroartemisinin can selec-
tively kill cancer cells in presence of holotransferrin
which can increase intracellular iron concentrations,
whereas normal breast cells (HTB 125) and lymphocytes
were not affected under the same condition. It seems
that the mechanisms underlying both antitumor and
antimalarial properties are similar.14ꢀ16
Posner’s group found some new artemisinin derivatives
and trioxane dimers which had antimalarial, anti-
proliferative and antitumor activities. Dimer 8a, 8b, 8c
were especially potent and selective at inhibiting growth
of some human cancercell lines, and 8a was evaluated
in vivo assay (Chart 1).17,18
Results and Discussion
Chemistry
In order to search for new artemisinin derivatives with
more potent antimalarial and antitumor activity, we
synthesized compounds 9, 10 and investigated their
In the presence of an acidic catalyst, dihydro-
artemisinin reacted with corresponding cyanohydrin to
Chart 2.

Y. Li et al. / Bioorg. Med. Chem. 11 (2003) 977–984
979
Chart 3.
give 12(16-R and 16-S) in moderate yield. Generally,
the pair of isomers could be separated by careful col-
umn chromatography. They are 12-b ethers as indi-
cated by the small coupling constants (Jꢁ3.5 Hz)
between 11-H and 12-H in their 1H NMR.22 The R
configuration of C-16 of 12k was established by X-ray
1.30) as compared with that of the 11b-methyl group
1
in 12s (d 1.04) and in 12t (d 0.96) in their H NMR
spectra (Scheme 1).23
In order to examine the role of peroxy group and cyano
group, we synthesized compound 13 and 14. 13 was
derived from 12l by reduction with zinc powder in acetic
acid21 and 14 was prepared by condensation of dihy-
droartemisinin and 3-hydroxy-3-phenyl-propionitrile
(Scheme 2).
1
diffraction.21 In the H NMR spectra of 12k and 12l,
the values of chemical shifts of C-12 and C-16 were
distinguishable (for 12k 5.22, 5.25; for 12l, 4.79, 5.46
respectively). Taking these data as a criterion, the ste-
reochemistry of other isomers could be deduced. When
dihydroartemisinin reacted with a-hydroxy-2-naphthyl-
acetonitrile, three compound were yielded, normal
products 12s, 12t and byproduct 12u, in which the sig-
nal due to 11a-methyl group appeared downfield (d
Biological results
Cytotoxicity and effect on the cell cycle distribution
were measured according to the procedures described
Scheme 1.

980
Y. Li et al. / Bioorg. Med. Chem. 11 (2003) 977–984
Scheme 2.
previously.21 VCR was used as a reference compound with
IC50 values of 18 and 2 nM forA549 and P388 cells,
respectively. Table 1 showed compound 12 to be cytotoxic
against L1210, A549, P388 and HT29 cells. At the con-
centration of 25- 500 nM, they induced a G1 accumulation
in L1210 cells and apoptosis in P388 cells (see Table 1).
12v vs 12w), it can be seen that the configuration
of C-16 had non-significant effect on the cyto-
toxicity, cell cycle and apoptosis.
4. Compound 12l was 1000-fold more cytotoxic
than 13. The peroxy group is clearly essential for
cytotoxicity.4,6
5. Compound 14 was devoid of effect on cell pro-
liferation. This lack of cytotoxicity suggested that
the cyanohydrin moiety must be present in the
molecule. The activity of compound 12 may be
due partly to its degradation products
arylcyanohydrin. So far as we know, mandelo-
nitrile glucosides having some similarity with the
chemical structure of compound 12 were studied
in cancer research and cancer theraphy.24
Conclusion
From these data, the following conclusion in terms of
structure–activity relationship can be drawn:
1. Compound 12 was more toxic against A549,
P388, L1210 cells than HT29 cells.
2. Among the compound 12 series, 12g, 12h, 12i,
12j, 12k, and 12l bearing Br substituent on the
phenyl ring were more active than others. 12k
and 12l were the most active and their IC50 could
be comparable to that of VCR, a very potent
cytotoxic agent.
Experimental
Melting points were taken in open capillary on BUCHI-
510 melting point apparatus and were uncorrected. The
3. From Table 1 (12k vs 12l, 12m vs 12n, 12s vs 12t,
Table 1. Inhibition of cell proliferation, perturbation of the cell cycle and induction of apoptosis by compounds 12, 13
No.
IC50 (nM)
Cell-cycle effect L1210
% G1 (nM)
Cell-cycle apoptosis P388
% apoptose
L1210
A549
P388
1855
HT29
% G1
nM
11
79,432
1227
662
364
306
10,600
8800
193
65
67
61
72
71
7
53
45
43
51
10,000
500
100
12a
12b
12c
12d
12e
12f
12g
12h
12i
113
34
38
41
470
620
27
150
19
238
48
43
77
290
440
28
92
20
108
12
11
105
152
13
84
70
4095
2213
447
1471
16,200
7400
9638
809
7788
748
179
490
69 (400)
200
250
68 (1000)
67 (2500)
70
72
46
58
100
100
741
85
437
47
71 (500)
68 (500)
12j
12k
12l
151
15
10
62
63
68
68
64
71
70
71
70
69
70
49
51
20
16
49
28
24
26
25
25
500
500
50
500
250
250
250
250
250
39
12m
12n
12o
12p
12s
12t
12v
12w
12x
13
17
221
1923
76
61
45
71
76
67
172
140
441
414
68 (250)
67 (250)
ND
ND
28
41,990
Inactive
24,200
Inactive
14
Control
42
4

Y. Li et al. / Bioorg. Med. Chem. 11 (2003) 977–984
981
IR spectra were run on a Perkin-Elmer 599B spectro-
photometer. 1H NMR spectra were determined in
CDCl3 solution on a NMR Brucker AM-400. Elemental
analyses were performed on a CE 1106 elemental ana-
lyser and all the results were within 0.4% of the theore-
tical values.
(3H, d, J=6.7 Hz, 11-CH3); 0.82 (3H, d, J=7.5 Hz, 10-
CH3). Anal. calcd forC 23H28FNO5: C 66.17, H 6.76, N
3.36, found: C 66.16, H 6.74, N 3.33.
(16-S) Cyano-(o-chloro-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12e). 12e: white crystal, mp 118–120 ꢂC
(from ethyl acetate–petroleum ether), yield 27%, 1H
NMR (400 MHz, d, ppm, CDCl3 ): 7.63 (1H, m, aro-
matic–H); 7.42 (1H, m, aromatic–H); 7.36 (2H, m, aro-
matic–H); 5.76 (1H, s, 5-H); 5.66 (1H, s, 16-H); 5.01
(1H, d, J=3.5 Hz, 12-H); 1.45 (3H, s, 4-CH3); 0.96 (3H,
d, J=6.4 Hz, 11-CH3); 0.88 (3H, d, J=7.2 Hz, 10-CH3).
Anal. calcd forC 23H28ClNO5: C 63.66, H 6.50, N 3.23;
found: C 63.42, H 6.29, N 3.08.
General procedure: synthesis of cyano-aryl-methyl 12ꢀ-
deoxoartemisinyl ether (12)
To a dichloromethane solution of dihydroartemisinin
(1.42 g, 5 mmol) and a 1.5 to 2-fold excess of a cyano-
hydrin fresh prepared from arylaldehyde at 0 to ꢀ20 ꢂC
was added trimethylsilyl trifluoromethanesulfonate or
boron trifluoride etherate (0.05–0.1 mL). The resulting
mixture was stirred at room temperature for 24 h, and
then washed with aqueous sodium bicarbonate and
brine. The organic layer was dried (MgSO4) and con-
centrated in vacuo to give the crude products. Pure
12(16-R) and 12(16-S) were obtained by column chro-
matography (silica gel) using petroleum ether–ethyl
acetate (100: 3ꢁ5 v/v) as eluent.
(16-S) Cyano-(p-chloro-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12f). 12f: white crystal, mp 126–128 ꢂC
(from ethyl acetate–petroleum ether), yield 39%, 1H
NMR (400 MHz, d, ppm, CDCl3): 7.51 (2H, d, J=8.5
Hz, aromatic–H); 7.24 (2H, d, J=8.5 Hz, aromatic-H);
5.57 (1H, s, 5-H); 5.46 (1H, s, 16-H); 4.78 (1H, d, J=3.5
Hz, 12-H); 1.42 (3H, s, 4-CH3); 0.98 (3H, d, J=6.5 Hz,
11-CH3); 0.81 (3H, d, J=7.4 Hz, 10-CH3). Anal. calcd
forC 23H28ClNO5: C 63.66, H 6.50, N 3.23; found: C
63.47, H 6.37, N 3.11.
(16-R) Cyano-phenyl-methyl 12ꢀ-deoxoartemisinyl ether
(12a) and (16-S) cyano- phenyl-methyl 12ꢀ-deoxoartemi-
sinyl ether (12b). 12a: white crystal, mp 135–137 ꢂC
1
(from ethyl ether), yield 22%, H NMR (400 MHz, d,
(16-S) Cyano-(o-bromo-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12g). 12g: white needle crystal, mp 128–
129 ꢂC (from ethyl acetate–petroleum ether), yield 18%,
1H NMR (400 MHz, d, ppm, CDCl3 ): 7.65 (1H, d, J=7.5
Hz, aromatic–H); 7.63 (1H, d, J=7.8 Hz, aromatic–H);
7.39 (1H, t, J=7.5 Hz, aromatic–H); 7.25 (1H, t, J=7.8
Hz, aromatic–H); 5.73 (1H, s, 5-H); 5.66 (1H, s, 16-H);
5.04 (1H, d, J=3.5 Hz, 12-H); 1.45 (3H, s, 4-CH3); 0.96
(3H, d, J=6.7 Hz, 11-CH3); 0.89 (3H, d, J=7.5 Hz, 10-
CH3). IR (KBr, cmꢀ1): 1571, 1470, 1446, 1377, 1194,
1101, 1032, 982, 931, 878. Anal. calcd forC 23H28BrNO5:
C 57.75, H 5.90, N 2.93; found: C 57.89, H 5.92, N 2.99.
ppm, CDCl3 ): 7.44 (5H, m, aromatic–H); 5.68 (1H, s, 5-
H); 5.28 (1H, s, 16-H); 5.24 (1H, d, J=3.6 Hz, 12-H);
1.43 (3H, s, 4-CH3); 1.01 (3H, d, J=7.3 Hz, 11CH3),
0.87 (3H, d, J=6.0 Hz, 10-CH3), IR (KBr, cmꢀ1): 1458,
1375, 1103, 1011, 875, 700. Anal. calcd forC 23H29NO5:
C 69.15, H 7.32, N 3.51; found: C 68.86, H 7.53, N 3.33.
12b: white crystal, mp 98–100 ꢂC (from ethyl ether),
1
yield 15%, H NMR (400 MHz, d, ppm, CDCl3 ): 7.42
(5H, m, aromatic–H); 5.60 (1H, s, 5-H); 5.50 (1H, s, 16-
H); 4.81 (1H, d, J=3.5 Hz, 12-H); 1.44 (3H, s, 4-CH3);
0.95 (3H, d, J=6.6 Hz, 11-CH3), 0.84 (3H, d, J=7.5
Hz, 10-CH3), IR (KBr, cmꢀ1): 1452, 1377, 1192, 1101,
878, 743. Anal. calcd forC 23H29NO5: C 69.15, H 7.32,
N 3.51; found: C 68.85, H 7.42, N 3.18.
(16-R) Cyano-(o-bromo-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12h). 12h: amorphous, yield 20%, 1H
NMR (400 MHz, d, ppm, CDCl3): 7.66 (1H, d, J=7.8
Hz, aromatic–H); 7.65 (1H, d, J=7.5 Hz, aromatic–H);
7.41 (1H, d, J=8.0 Hz, aromatic–H); 7.25 (1H, d, J=8.0
Hz, aromatic–H); 5.99 (1H, s, 5-H); 5.43 (1H, s, 16-H);
5.30 (1H, d, J=3.7 Hz, 12-H); 1.43 (3H, s, 4-CH3); 1.01
(3H, d, J=5.6 Hz, 11-CH3); 0.89 (3H, d, J=5.8 Hz, 10-
CH3). IR (KBr, cmꢀ1): 1471, 1448, 1375, 1446, 1194,
1101, 1009, 875. Anal. calcd forC 23H28BrNO5: C 57.75,
H 5.90, N 2.93; found: C 57.84, H 5.83, N 2.82.
(16-S) Cyano-(o-fluoro-phenyl)-methyl 12ꢀ-deoxoartemi-
sinyl ether (12c). 12c: white crystal, mp 147–148 ꢂC
(from ethyl acetate–petroleum ether), yield 29%, 1H
NMR (400 MHz, d, ppm, CDCl3 ): 7.53 (1H, t, J=7.6
Hz, aromatic–H); 7.38 (1H, m, aromatic–H); 7.19 (1H,
t, J=7.3 Hz, aromatic–H); 7.09 (1H, t, J=9.5 Hz, aro-
matic–H); 5.70 (1H, s, 5-H); 5.61 (1H, s, 16-H); 4.90
(1H, d, J=3.5 Hz, 12-H); 1.38 (3H, s, 4-CH3); 0.85 (3H,
d, J=6.4 Hz, 11-CH3); 0.81 (3H, d, J=7.5 Hz, 10-CH3).
Anal. calcd forC 23H28FNO5: C 66.17, H 6.76, N 3.36;
found: C 66.07, H 6.78, N 3.35.
(16-S) Cyano-(m-bromo-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12i). 12i: white crystal, mp 145–146 ꢂC
(from ethyl acetate–petroleum ether), yield 19%, 1H
NMR (400 MHz, d, ppm, CDCl3): 7.59 (1H, s, aro-
matic–H); 7.54 (1H, d, J=7.9 Hz, aromatic–H); 7.38
(1H, d, J=7.8 Hz, aromatic–H); 7.28 (1H, t, J=7.8 Hz,
aromatic–H); 5.58 (1H, s, 5-H); 5.47 (1H, s, 16-H); 4.81
(1H, d, J=3.5 Hz, 12-H); 1.44 (3H, s, 4-CH3); 0.96 (3H,
d, J=6.4 Hz, 11-CH3); 0.87 (3H, d, J=7.2 Hz, 10-CH3).
IR (KBr, cmꢀ1): 1576, 1473, 1433, 1379, 1194, 1101,
1036, 984, 957, 874. Anal. calcd forC 23H28BrNO5: C
57.75, H 5.90, N 2.93; found: C 57.79, H 5.90, N 2.99.
(16-S) Cyano-(p-fluoro-phenyl)-methyl 12ꢀ-deoxoartemi-
sinyl ether (12d). 12d: white crystal, mp 146–147 ꢂC
(from ethyl acetate–petroleum ether), yield 24%, 1H
NMR (400 MHz, d, ppm, CDCl3 ): 7.43 (1H, d, J=8.6
Hz, aromatic-H); 7.42 (1H, d, J=8.6 Hz, aromatic-H);
7.09 (1H, t, J=8.6 Hz, aromatic–H); 7.08 (1H, t, J=8.5
Hz, aromatic–H); 5.57 (1H, s, 5-H); 5.47 (1H, s, 16-H);
4.78 (1H, d, J=3.5 Hz, 12-H); 1.41 (3H, s, 4-CH3); 0.88

982
Y. Li et al. / Bioorg. Med. Chem. 11 (2003) 977–984
(16-R) Cyano-(o-bromo-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12j). 12j: amorphous, yield 22%, 1H
NMR (400 MHz, d, ppm, CDCl3): 7.61 (1H, s, aro-
matic–H); 7.55 (1H, d, J=7.9 Hz, aromatic–H); 7.39
(1H, d, J=7.8 Hz, aromatic–H); 7.31 (1H, t, J=7.8 Hz,
aromatic–H); 5.64 (1H, s, 5-H); 5.26 (1H, s, 16-H); 5.23
(1H, d, J=3.7 Hz, 12-H); 1.43 (3H, s, 4-CH3); 1.01 (3H,
d, J=7.5 Hz, 11-CH3); 0.90 (3H, d, J=6.0 Hz, 10-CH3).
IR (KBr, cmꢀ1): 1574, 1475, 1377, 1446, 1194, 1103,
1013, 874. Anal. calcd forC 23H28BrNO5: C 57.75, H
5.90, N 2.93; found: C 57.94, H 5.92, N 2.92.
(16-R) Cyano-(m, p-dimethoxy-phenyl)-methyl 12ꢀ-
deoxoartemisinyl ether (12o). 12o oil, yield 25%, 1H
NMR (400 MHz, d, ppm, CDCl3): 7.02 (1H, d, J=8.4
Hz, aromatic–H); 6.95 (1H, s, aromatic–H); 6.88 (1H, d,
J=8.1 Hz, aromatic–H); 5.60 (1H, s, 5-H); 5.26 (1H, s,
16-H); 5.20 (1H, d, J=3.6 Hz, 12-H); 3.83 (3H, s,
OMe); 3.81 (3H, s, OMe); 1.43 (3H, s, 4-CH3); 1.00 (3H,
d, J=7.4 Hz, 11-CH3); 0.88 (3H, d, J=6.2 Hz, 10-CH3).
IR (KBr, cmꢀ1): 1684, 1597, 1518, 1456, 1100, 1040,
950, 875. Anal. calcd forC 25H33NO7: C 65.34, H 7.24,
N 3.05; found: C 65.45, H 7.22, N 2.89.
(16-R) Cyano-(p-bromo-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12k). 12k: white crystal, mp 128–129 ꢂC
(from ethyl acetate–petroleum ether), yield 23%, 1H
NMR (400 MHz, d, ppm, CDCl3 ): 7.57 (2H, d, J=8.5
Hz, aromatic–H); 7.33 (2H, d, J=8.5 Hz, aromatic–H);
5.63 (1H, s, 5-H); 5.25 (1H, s, 16-H); 5.22 (1H, d, J=3.7
Hz, 12-H); 1.43 (3H, s, 4-CH3); 1.00 (3H, d, J=7.4 Hz,
11-CH3); 0.90 (3H, d, J=6.1 Hz, 10-CH3). IR (KBr,
cmꢀ1): 1593, 1489, 1375, 1101, 1032, 1011, 955, 876.
Anal. calcd forC 23H28BrNO5: C 57.75, H 5.90, N 2.93;
found: C 57.80, H 6.07, N 2.85.
(16-S) Cyano-(o, p-dimethyl-phenyl)-methyl 12ꢀ-deoxo-
1
artemisinyl ether (12p). 12p: oil, yield 64%, H NMR
(400 MHz,d, ppm, CDCl3): 7.41 (1H, d, J=7.7 Hz,
aromatic–H); 7.04 (1H, d, J=7.7 Hz, aromatic–H); 7.03
(1H, s, aromatic–H); 5.77 (1H, s, 5-H); 5.46 (1H, d,
J=5.4 Hz, 12-H); 5.38 (1H, s, 16-H); 2.41 (3H, s,
Me); 2.31 (3H, s, Me); 1.45 (3H, s, 4-CH3); 1.23
(3H, d, J=7.2 Hz, 11-CH3); 0.91 (3H, d, J=6.0
Hz, 10-CH3). IR (KBr, cmꢀ1): 1616, 1502, 1452,
1377, 1194, 1101, 1010, 956, 875. Anal. calcd for
C25H33NO5: C 70.23, H 7.78, N 3.28; found: C 70.37, H
7.58, N 3.19.
(16-S) Cyano-(p-bromo-phenyl)-methyl 12ꢀ-deoxoarte-
misinyl ether (12l). 12l: white needle crystal, mp 144–
145 ꢂC (from petroleum ether), yield 25%, 1H NMR
(400 MHz, d, ppm, CDCl3): 7.55 (2H, d, J=8.3 Hz,
aromatic–H); 7.32 (2H, d, J=8.4 Hz, aromatic–H); 5.58
(1H, s, 5-H); 5.46 (1H, s, 16-H); 4.79 (1H, d, J=3.4 Hz,
12-H); 1.44 (3H, s, 4-CH3); 0.96 (3H, d, J=6.3 Hz, 11-
CH3); 0.85 (3H, d, J=7.3 Hz, 10-CH3). IR (KBr, cmꢀ1):
1593, 1487, 1394, 1144, 1103, 1036, 955, 879. Anal.
calcd forC 23H28BrNO5: C 57.75, H 5.90, N 2.93; found:
C 57.80, H 5.89, N 2.96.
(16-R) Cyano-(10-naphthyl)-methyl 12ꢀ-deoxoartemisi-
nyl ether (12q) and (16-S) cyano- (10-naphthyl)-methyl
12ꢀ-deoxoartemisinyl ether (12r). 12q: amorphous,
1
yield 24%, H NMR (400 MHz,d, ppm, CDCl3): 8.17
(1H, d, J=8.6 Hz aromatic–H); 7.92 (1H, t, J=7.1 Hz,
aromatic–H); 7.75 (1H, d, J=7.0 Hz, aromatic–H); 7.59
(3H, m, aromatic–H); 7.51 (1H, t, J=7.7 Hz, aromatic–
H); 6.26 (1H, s, 5-H); 5.39 (1H, d, J=3.7 Hz, 12-H);
5.30 (1H, s, 16-H); 1.47 (3H, s, 4-CH3); 1.09 (3H, d,
J=7.3 Hz, 11-CH3), 0.82 (3H, d, J=6.2 Hz, 10-CH3).
IR (KBr, cmꢀ1): 1512, 1450, 1377, 1194, 1101, 1009,
955, 876. Anal. calcd forC 27H31NO5: C 72.14, H 6.95,
N 3.12; found: C 72.47, H 7.33, N 2.99.
(16-S) Cyano-(o, p-dimethoxy-phenyl)-methyl 12ꢀ-
deoxoartemisinyl ether (12m). 12m: white crystal, mp
149–150 ꢂC (from ethyl acetate–petroleum ether), yield
1
20%, H NMR (400 MHz, d, ppm, CDCl3 ): 7.40 (1H,
12r: amorphous, yield 15%, 1H NMR (400 MHz, d,
ppm, CDCl3): 8.19 (1H, d, J=8.2 Hz, aromatic–H);
7.92 (1H, t, J=6.0 Hz, aromatic–H); 7.60 (4H, m, aro-
matic–H); 7.48 (1H, t, J=4.1 Hz, aromatic–H); 6.03
(1H, s, 5-H); 5.70 (1H, s, 16-H); 4.86 (1H, d, J=3.6 Hz,
12-H); 1.48 (3H, s, 4- CH3); 0.99 (3H, d, J=6.3 Hz, 11-
CH3), 0.71 (3H, d, J=7.4 Hz, 10-CH3). IR (KBr, cmꢀ1):
1512, 1452, 1373, 1194, 1101, 1011, 986, 876. Anal.
calcd forC 27H31NO5: C 72.14, H 6.95, N 3.12; found: C
72.27, H 6.92, N 3.08.
d, J=8.5 Hz, aromatic–H); 6.49 (1H, d, J=8.4 Hz,
aromatic–H); 6.43 (1H, s, aromatic–H); 5.71 (1H, s,
5-H); 5.63 (1H, s, 16-H); 4.91 (1H, d, J=3.5 Hz, 12-H);
3.81 (3H, s, OCH3); 3.80 (3H, s, OCH3); 1.45 (3H, s,
4-CH3); 0.95 (3H, d, J=6.4 Hz, 11-CH3); 0.81 (3H, d,
J=7.5 Hz, 10-CH3). IR (KBr, cmꢀ1): 1616, 1585, 1508,
1464, 1265, 1209, 1103, 1099, 987, 955, 937, 874. Anal.
calcd forC 25H33NO7: C 65.34, H 7.24, N 3.05; found: C
65.48, H 7.29, N 3.11.
(16-R) Cyano-(o, p-dimethoxy-phenyl)-methyl 12ꢀ-
deoxoartemisinyl ether (12n). 12n: white crystal, mp
149–152 ꢂC (from ethyl acetate–petroleum ether), yield
22%, 1H NMR (400 MHz, d, ppm, CDCl3 ): 7.46 (1H, d,
J=8.4 Hz, aromatic–H); 6.51 (1H, d, J=8.4 Hz, aro-
matic–H); 6.45 (1H, s, aromatic–H); 5.98 (1H, s, 5-H);
5.40 (1H, s, 16-H); 5.21 (1H, d, J=3.4 Hz, 12-H); 3.83
(3H, s, OCH3); 3.81 (3H, s, OCH3); 1.44 (3H, s, 4-CH3);
0.97 (3H, d, J=7.4 Hz, 11-CH3); 0.90 (3H, d, J=6.0 Hz,
10-CH3). IR (KBr, cmꢀ1): 1616, 1589, 1510, 1464, 1284,
1211, 1126, 1097, 1040, 995, 957, 870. Anal. calcd for
C25H33NO7: C 65.34, H 7.24, N 3.05; found: C 65.41, H
7.15, N 3.05.
(16-R) Cyano-(20-naphthyl)-methyl 12ꢀ-deoxoartemisi-
nyl ether (12s), (16-S) cyano- (20-naphthyl)-methyl 12ꢀ-
deoxoartemisinyl ether (12t) and (16-R) cyano- (20-naph-
thyl)-methyl 12ꢀ-(11S) deoxoartemisinyl ether (12u).
12s: amorphous, yield 25%, 1H NMR (400 MHz, d,
ppm, CDCl3 ): 7.97 (1H, s, aromatic–H); 7.90 (3H, m,
aromatic–H); 7.54 (3H, m, aromatic–H); 5.84 (1H, s, 5-
H); 5.34 (1H, s, 16-H); 5.30 (1H, d, J=3.6 Hz, 12-H);
1.45 (3H, s, 4-CH3); 1.04 (3H, d, J=7.3 Hz, 11-CH3),
0.86 (3H, d, J=6.2 Hz, 10-CH3). IR (KBr, cmꢀ1): 1602,
1510, 1450, 1377, 1194, 1101, 1011, 955, 939, 876, 825.
Anal. calcd forC 27H31NO5: C 72.14, H 6.95, N 3.12,
found: C 72.20, H 6.74, N 3.19.

Y. Li et al. / Bioorg. Med. Chem. 11 (2003) 977–984
983
12t: amorphous, yield 26%, 1H NMR (400 MHz, d,
ppm, CDCl3): 7.91 (1H, s, aromatic–H); 7.86 (3H, m,
aromatic–H); 7.54 (3H, m, aromatic–H); 5.67 (1H, s, 5-
H); 5.64 (1H, s, 16-H); 4.86 (1H, d, J=3.5 Hz, 12-H);
1.46 (3H, s, 4-CH3); 0.96 (3H, d, J=6.3 Hz, 11-CH3),
0.84 (3H, d, J=7.2 Hz, 10-CH3). IR (KBr, cmꢀ1): 1602,
1510, 1450, 1377, 1280, 1226, 1194, 1101, 1032, 955,
937, 876, 825. Anal. calcd forC 27H31NO5: C 72.14, H
6.95, N 3.12; found: C 71.96, H 6.90, N 3.28.
at 0 ꢂC was added Zn powder(100 mg). Then the mix-
ture was stirred at room temperature for 2 h. Iced water
was added and the mixture was extracted with chloro-
form. The organic layer was washed with aqueous
sodium bicarbonate and brine. The organic layer was
dried (MgSO4) and concentrated in vacuo. The crude
product was recrystallized to give pure 13 (58 mg, yield
60%).
13: white crystal, mp 122–122.5 ꢂC (from ethyl acetate–
petroleum ether), 1H NMR (400 MHz, d, ppm, CDCl3 ):
7.54 (2H, d, J=8.5 Hz, aromatic–H); 7.31 (2H, d,
J=8.5 Hz, aromatic–H); 5.47 (1H, s, 5-H); 5.34 (1H, s,
16-H); 4.78 (1H, d, J=4.1 Hz, 12-H); 1.47 (3H, s, 4-
CH3); 0.91 (3H, d, J=7.3 Hz, 11-CH3); 0.88 (3H, d,
J=6.4 Hz, 10-CH3). IR (KBr, cmꢀ1): 1593, 1487, 1394,
1211, 1103, 930, 868. Anal. calcd forC 23H28BrNO4: C
59.74, H 6.10, N 3.03; found: C 59.85; H 5.78, N 3.31.
12u: white crystal, mp 144–146 ꢂC, yield 5%, H NMR
1
(400 MHz, d, ppm, CDCl3 ): 8.01 (1H, s, aromatic–H);
7.91–7.84 (3H, m, aromatic–H); 7.58 (1H, d, J=8.5 Hz
aromatic–H); 7.52 (2H, m aromatic–H); 5.88 (1H, s, 5-
H); 5.50 (1H, d, J=4.3 Hz, 12-H); 5.45 (1H, s, 16-H);
1.47 (3H, s, 4-CH3); 1.30 (3H, d, J=6.2 Hz, 11-CH3),
0.91 (3H, d, J=6.1 Hz, 10-CH3). IR (KBr, cmꢀ1): 1604,
1510, 1458, 1377, 1203, 1126, 1090, 1003, 885. Anal.
calcd forC 27H31NO5: C 72.14, H 6.95, N 3.12; found: C
72.01, H 6.78, N 3.12.
(Cyanomethyl)-benzyl 12ꢀ-deoxoartemisinyl ether (14).
Dihydroartemisinin (200 mg, 0.7 mmol) reacted with 3-
hydroxy-3-phenyl-propionitrile using boron trifluoride
etherate as a catalyst, according to the general proce-
dure. The product was a mixture of 16R and 16S iso-
mers (amorphous, 84 mg, yield 29%).
(16-R)
Cyano-[m-(30-trifluorophenoxy)-phenyl]-methyl
12ꢀ-deoxoartemisiny ether (12v) and (16-S) cyano-[m-
(30-trifluorophenoxy)-phenyl]-methyl 12ꢀ-deoxo-artemi-
1
siny ether (12w). 12v: amorphous, yield 23%, H NMR
(400 MHz, d, ppm, CDCl3): 7.46–7.37 (4H, m, aro-
matic–H); 7.21 (1H, s, aromatic–H); 7.17 (1H, d, J=7.8
Hz, aromatic–H); 7.08 (1H, s, aromatic–H); 7.05 (1H, d,
J=8.1 Hz, aromatic–H); 5.57 (1H, s, 5-H); 5.48 (1H, s,
16-H); 4.82 (1H, d, J=3.2 Hz, 12-H) ;1.43 (3H, s, 4-
CH3); 0.95 (3H, d, J=6.2 Hz, 11-CH3); 0.80 (3H, d,
J=7.3 Hz, 10-CH3). IR (KBr, cmꢀ1): 1589, 1489, 1450,
1329, 1130, 876. Anal. calcd forC 30H32F3NO6: C 64.39,
H 5.76, N 2.50; found: C 64.32, H 5.77, N 2.50.
1H NMR (400 MHz, d, ppm, CDCl3): 7.38 (5H, m,
aromatic–H); 5.74, 5.63 (1H, s, s, 5-H); 5.19, 5.17 (1H,
m, 16-H); 4.79, 4.65 (1H, d, d, J=3.7 Hz, 12-H); 2.68
(2H, m, 17-H); 1.39 (3H, s, 4-CH3); 0.94 (3H, d, J=6.2
Hz, 11-CH3), 0.87 (3H, d, J=7.3 Hz, 10-CH3). IR (KBr,
cmꢀ1): 1456, 1375, 1194, 1101, 1013, 981, 875 Anal.
calcd forC 24H31NO5: C 69.71, H 7.56 , N 3.39; found: C
69.52H 7.56 N 2.99.
12w: amorphous, yield 22%, 1H NMR (400 MHz, d,
ppm, CDCl3): 7.47–7.37 (4H, m, aromatic–H); 7.25 (1H,
s, aromatic–H); 7.16 (1H, d, J=7.9 Hz, aromatic–H);
7.12 (1H, s, aromatic–H); 7.06 (1H, d, J=7.7 Hz, aro-
matic–H); 5.67 (1H, s, 5-H); 5.24 (1H, s, 16-H); 5.23
(1H, d, J=3.0 Hz, 12-H); 1.42 (3H, s, 4-CH3); 0.98 (3H,
d, J=7.3 Hz, 11-CH3); 0.89 (3H, d, J=6.2 Hz, 10-CH3).
IR (KBr, cmꢀ1): 1589, 1489, 1450, 1329, 1130, 876.
Anal. calcd forC 30H32F3NO6: C 64.39, H 5.76, N 2.50;
found: C 64.54, H 5.81, N 2.38.
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