Synthesis of egonol derivatives and their antimicrobial activities

Article abstract of DOI:10.1016/j.bmc.2010.12.044

Eighteen derivatives of egonol (A-R) were synthesized and evaluated for their antimicrobial activities against Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231 and Escherichia coli ATCC 8739 microorganisms compari

Full text of DOI:10.1016/j.bmc.2010.12.044

Bioorganic & Medicinal Chemistry 19 (2011) 1179–1188
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry
journal homepage: www.elsevier.com/locate/bmc
Synthesis of egonol derivatives and their antimicrobial activities
⇑
Safiye Emirdag˘-Öztürk , Tamer Karayildirim, Hüseyin Anil
_
Chemistry Department, Faculty of Science, Ege University, Bornova, Izmir 35100, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Eighteen derivatives of egonol (A–R) were synthesized and evaluated for their antimicrobial activities
against Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231
and Escherichia coli ATCC 8739 microorganisms comparing with egonol. The obtained data reported that
compound B exhibited improved activities against all tested bacteria than egonol, others have shown dif-
ferent range of activities.
Received 31 October 2010
Revised 18 December 2010
Accepted 21 December 2010
Available online 28 December 2010
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Egonol
Benzofuran
Antimicrobial activity
1. Introduction
cinalis and its isolation procedure was explained in our previous
work.10
Lignans and neolignans are important targets for organic syn-
thesis due to the wide variety of biologically active products, which
are members of these classes.1,2 Benzofuran neolignans and nor-
neolignans, which are contained in most plants, especially in the
Styracaceae family, such as Styrax japonicum, Styrax formosanus, Sty-
rax obassia, Styrax macranthus and Styrax officinalis show a variety
of biological activities including insecticidal, fungicidal, antimicro-
bial, anti sweet, antiproliferative, cytotoxic and antioxidant prop-
erties.3 The phytochemical investigation on this genus increased
in 1915, when Okada isolated egonol for the first time, as an unsa-
ponifiable constituent of the seed oil of S. Japonica.4
Egonol, a natural 2-aryl benzofuran, is known to be an effective
pyrethrum synergist.5 Egonol and its derivatives attracted the atten-
tion of synthetic chemists due to their antibacterial and antifungal,6
anti-complement7 activities besides their considerable cytotoxic
activities against human leukaemic HL-60 cells.8 It was also re-
ported that significant activities were observed for egonol against
C6 (rat glioma) and Hep-2 (larynx epidermoid carcinoma) cell lines.9
As part of our ongoing studies, a series of new benzofuran deriv-
atives (A–R) derived from egonol scaffold were prepared and their
antimicrobial activities were evaluated hereby.
The reaction of egonol with triethylamine and chloroacetyl chlo-
ride in dry diethyl ether at room temperature gave compound A,
whose molecular formula is C21H19ClO6 and the molecular ion peaks
were at m/z 403.0 and 405.0 [M]+. Most of the 1H and 13C NMR signals
of compound A were similar to those of egonol, which is isolated in
our previous work,10 besides the extra 1H NMR signal at dH 4.05 (2H,
s) and 13C NMR signal at dC 41.10 which correspond to two hydrogen
and methylene carbon signals of chloroacetyl group, respectively.
Moreover, the signal for carbonyl carbon at dC 167.56 in the 13C
NMR spectrum indicated that hydroxyl group was converted to an
ester group. Apart from these, shifting of C-300 signal from dC 62.70
to dC 65.74 in the 13C NMR spectrum and also the chemical shifts
of H-300 from dH 3.73 to 4.25 in the 1H NMR spectrum showed that
the primary alcohol group was converted to chloroester group. In
the IR spectrum of A absorption band at 1750 cmꢀ1 and the disap-
pearance of hydroxyl absorption band at 3741 cmꢀ1 also confirmed
completion of the substitution reaction. On the basis of these spec-
troscopic data compound A was elucidated as 3-[2-(1,3-ben-
zodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propyl chloroacetate.
In order to synthesise compound B, egonol was reacted with
sulfuric acid in a mixture of acetonitrile and CH2Cl2. The positive
ion mode LCMS/APCI analysis of compound 7 gave the molecular
ion peaks at m/z 406.0 [M]+ and 327.0 for the [Mꢀ(HSO3)+2H]+.
The shifting of both H-300 and C-300 signals from dH 3.73 to 4.06
and dC 62.70 to 67.30 in 1H and 13C NMR spectra, respectively,
proved the conversion of primary alcohol to hydrogen sulfate. Fur-
thermore, the IR spectrum exhibited strong absorption bands at
2. Results and discussion
2.1. Synthesis of egonol derivatives
The synthesis of egonol derivatives was figured out in Figures 1
and 2. The starting material was isolated from the seeds of S. offi-
1214 cmꢀ1
, consistent with the presence of sulfate groups.
According to the above mentioned results, compound B was de-
duced as 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-
yl]propyl hydrogen sulfate whose molecular formula is C19H18O8S.
⇑
Corresponding author. Tel.: +90 232 311 2371; fax: +90 232 388 8264.
E-mail address: safiye.emirdag@ege.edu.tr (S. Emirdag˘-Öztürk).
0968-0896/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2010.12.044

1180
S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
O
O
O
HO
S
N
O
O
O
O
O
O
O
O
O
NO2
OMe
OMe
HO
O
O
Compound I
Compound B
O
O2N
OMe
O
Cl
Compound C
O
4
1''
3''
3
O
O
5
3a
2'
5'
HO
2
O
OMe
2''
3'
4'
1'
O
O
6
O
7a
O
7
1
6'
O
OMe
Egonol
Compound A
O
O
O
OMe
Compound D
HO
OMe
OMe
Cl
O
O
O
O
OMe
NO2
OMe
Trimethoxy egonol
HO
Compound 210
O
O
O
O
N
NO2
OMe
Compound 810
Cl
x
O
O
O
OMe
Cl
O
O
O
O
O
OMe
NH2
OMe
OMe
y
Compound E
OMe
z
HO
O
O
Compound J
Compound F
O
OMe
N
Compound H
O
O
O
O
OMe
Compound G
Figure 1. Synthetic pathway of compounds A–J.
O
HO
O
O
O
H
O
O
3'''''
2'''''
1'''''
OMe
Egonol
O
OMe
OH
5'''
6''''
7'''
4'''
3a'
O
O
Compound P
O
O
O
H
MeO
3'''
7a'
O
O
1'''O
2'''
OMe
O
1''''
2''''
3''''
O
6'''
OMe
Compound K
5''''
Compound 110
4''''
H
H
O
O
H
H2N
N
N
O
O
O
O
O
O
O
H
OMe
OMe
HO
N
Compound L
O
O
Compound O
O
OMe
H
H
N
H2N
N
Compound N
O
O
S
O
OMe
C
Compound M
D
B
A
H
H
O
O
C
Cl
N
N
B
O
O
O
O
O
O
O
O
OMe
Compound R
Figure 2. Synthetic pathway of compounds K–R.
OMe
Compound Q
Adding egonol into potassium nitrate in sulfuric acid media in
CH2Cl2 resulted in compound C. The molecular formula of com-
pound C was established as C19H16N2O9 by positive ion mode
LCMS/APCI analysis, the peaks were at m/z 416.10 [M]+, 403.0
[Mꢀ(OH)+3H]+, 327.05 [Mꢀ2ꢁ(NO2)+H]+. The disappearance of
lH NMR signals at dH 6.81 and 6.66 for H-3 and H-6, respectively,

S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
1181
consistent with electrophilic aromatic nitration of egonol that was
placed at C-3 and C-6 positions. The chemical shifts of C-3 and C-6,
from dC 100.76 to 125.51 for the former and from dC 107.86 to
140.38 for the latter in 13C NMR spectra also supported nitration
of C-3 and C-6 positions of egonol. The presence of typical absorp-
tion bands at 1543 cmꢀ1 (N–O asymmetric stretch) and 1354 cmꢀ1
(N–O symmetric stretch) in the IR spectrum in the final product
confirmed the successful nitration of egonol. Thus, the structure
of new compound C was established as 5-[300-hydroxypropyl]-7-
methoxy-3,6-dinitro-2-(30,40methylene dioxyphenyl) benzofuran.
Compound D, which was previously isolated from Styrax spe-
cies,11 was obtained from the reaction of egonol with acetic anhy-
dride. The reaction of egonol with acetic anhydride gave 3-[2-(1,3-
benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propylacetate (D).
LCMS/APCI spectrum gave the peaks at m/z 368 [M]+, 279.0
[Mꢀ(CH3–COO–CH2–CH2)ꢀ2H]+ and is appropriate for a molecular
formula of C21H20O6. Analysis of 1H and 13C NMR data of D in com-
parison with those of egonol, clearly indicated that the difference
between the two compounds should be confined to the occurrence
of acetoxy group instead of a primary alcoholic function. In the 1H
NMR spectrum of compound D, a new additional signal belonging
to methyl protons of acetoxy group at dH 2.13 (s, 3H) and shifting of
H-300 signal from dH 3.73 (t, 2H, J = 6.4, 6.4) to 4.13 (t, 2H, J = 6.4,
6.8) indicated that hydroxyl group was acetylated. This conversion
was also supported by an absorption band at 1736 cmꢀ1 (C@O
stretching) in the IR spectrum. These results allowed us to deduce
the structure 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]propyl acetate for D.
methylenes, adjacent to the ether oxygen of the morpholine ring
and this signal correlates to a single –CH2– peak at dC 67.15 in
13C NMR spectrum. Similarly, a 1H NMR multiplet at dH 2.38 corre-
sponding to four protons is assigned to the H-5000 and H-3000 methy-
lene protons adjacent to the nitrogen atom and correlates to a
single –CH2– peak at dC 53.93 in 13C NMR spectrum. Therefore,
compound G was determined as 4-{3-[2-(1,3-benzodioxol-5-yl)-7-
methoxy-1-benzofuran-5-yl]propyl}morpholine.
Compound H was prepared from 5-[300-hydroxypropyl]-7-meth-
oxy-3-nitro-2-(30,40-methylenedioxyphenyl)benzofuran (compound
8),10 and hydrazine monohydrate in EtOH. The LCMS/APCI mass
spectrum of H showed a major ion peak at m/z 345.10 [M+4H]+
ascribable to the molecular formula C19H19O5N and also a peak at
m/z 327.0 [Mꢀ(NH2)+2H]+ corresponding to the loss of –NH2
group. The NMR data of H were in good agreement with those of
compound 8,10 except for the downfield shift of C-3 at dC 168.32,
C-2 at d 122.68, and C-4 at d 163.12, suggesting that H was a {5-
[300-hydroxypropyl]-7-methoxy-3-amino-2-(30,40methylene dioxyphe-
nyl) benzofuran}.
In order to synthesize compound I, compound A was reacted
with morpholine. LCMS/APCI mass spectrum of I showed major
ion peaks at m/z 454.10 [M+H]+ and 455.10 [M+2H]+ ascribable
to the molecular formula C25H27NO7 and also a peak at m/z
327.10 [Mꢀ(O–(CH2CH2)2N–CH2–CO)+H]+. The signals due to
methine protons at dH 3.76 on oxygen-bearing carbon atoms and
at 2.60 on nitrogen-bearing carbon atoms appeared in the 1H
NMR spectrum. The resonances for the oxygenated carbons also
indicated the presence of two oxymethine carbons at dC 67.01
and two nitrogenated carbons at dC 53.53. Besides, the proton sig-
nal of –CH2COO– group was shifted to upfield region dH 3.20 (Table
2). Thus, the structure of I was determined as 3-[2-(1,3-ben-
Compounds E, F, and G were synthesized from 5-[300-chloropro-
pyl]-7-methoxy-2-(30,40-methylenedioxyphenyl) benzofuran (com-
pound 2), which was isolated in our previous study.10 The
reaction of compound 2 and diethylamine in chloroform afforded
compound E. LCMS/APCI spectrum gave m/z 382.10 [M+H]+
(100), 383.10 [M+2H]+ (24.3), 354.10 [Mꢀ(2ꢁCH3)+3H]+ (4.8),
307 [Mꢀ(N(CH3CH2)2)+2H]+ (3.5) and is appropriate for a molecu-
lar formula of C23H27NO4. In the 1H NMR spectrum, the three meth-
ylene groups of the alkyl chain were observed at dH 2.87 (H-100),
2.14 (H-200), and 2.77 (H-300) instead of at dH 2.86, 2.16 and 3.57
for compound 2. New additional signals belonging to methylenic
and methylic protons of –(N–CH2CH3)2 group were recorded at
dH 2.98 (4H, m) and at dH 1.27 (6H, q), respectively. 13C NMR data
of the compound also confirmed the proposed structure. Charac-
teristic signals were observed at dC 46.75 and 9.34 for methylene
and methyl carbons of –(N–CH2CH3)2 group, respectively. More-
zodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propyl
morpholin-4-
ylacetate.
Compound J was obtained from the reaction of trimethoxy
egonol with chloroacetyl chloride in dried diethyl ether. LCMS/
APCI of J gave a molecular ion peak at m/z 419.10 [M]+, appro-
priate for a molecular formula of C22H23ClO6. The chloroacetyla-
tion of trimethoxy egonol supported by the presence of
1 H NMR
methylene signal at dH 4.26 in the
spectrum and also
the carbonyl peak at 1731 cmꢀ1 in the IR spectrum. Shifting of
H-300 signal from dH 3.57 to 4.26 in the 1H NMR spectrum also
showed that the primary alcohol group converted to chloroester
group. Therefore, the structure of compound J was assigned as 3-
[2-(3,4-dimethoxyphenyl)-7-methoxy-1-benzofuran-5-yl]propyl
chloroacetate.
13
over, the C NMR spectrum showed that the C-300 signals reso-
nated at dC 51.12 instead of at dC 44.46 for compound 2 (Table
4). Thus, the structure of E was established as {3-[2-(1,3-ben-
zodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propyl}diethylamine.
The product of the reaction of compound 2 with KNO3 and
H2SO4 gave compound F, whose molecular formula is C19H16ClNO6
and the molecular ion peaks were at m/z 391.2 [M+H]+ and 392.2
[M]+. Full assignments of the proton and carbon signals of F in
comparison with those of 2 showed their considerable structural
similarity. (Tables 2 and 4). The difference consisted only absence
of the signals at dH 6.77/dC 100.56 (H-3/C-3 in compound 2) and the
presence of a signal at dC 140.48 instead of dC 100.56 in compound
F, which indicated that the nitration reaction took place at C-3 po-
sition. On the basis of these evidence, the structure of compound F
was established as 5-(300-chloropropyl)-7-methoxy-3-nitro-2-
(30,40methylene dioxyphenyl)benzofuran.
3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]prop-
anal (compound 1)10 was used as a starting material for the syn-
thesis of compounds K–P. The reaction of compound 1 with H2O2
in acetone gave the oxidation product (compound K). The positive
ion mode LCMS/APCI analysis of compound K gave the pseudomo-
lecular ion peaks at m/z 341.0 [M+H]+ and 323.0 for the [MꢀOH]+.
The disappearing of the aldehyde proton signal at dH 9.85 and shift-
ing of C-3 signal to dC 174.63 indicated that compound K was 3-[2-
(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl] propanoic acid.
The reaction of compound 1 and semicarbazide in MeOH affor-
ded compound L. The molecular formula of compound L was estab-
lished as C20H19N3O5 by positive ion mode LCMS/APCI mass
spectrum peaks at m/z 380.0 [M+H]+, 307 [Mꢀ(NH2CONHN)+H]+.
The semicarbazone derivative exhibited characteristic amide
bonds at 3466–3196 cmꢀ1 and 1698 cmꢀ1 in the IR spectrum. A
sharp band at 1582 cmꢀ1 in the semicarbazone derivative was
attributed to the characteristic –C@N group. Moreover, extra 1H
NMR signals at dH 6.07 (NH2C@O) and 9.75 (NH2CONH) and shift-
ing H-300 signal from dH 9.85 to 7.20 also confirmed completion of
the reaction. Thus, compound L was identified as 3-[2-(1,3-ben-
zodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl] propanal semicarbazone.
The reaction of compound 2 with morpholine gave compound
G, which was identified as a morpholine derivative of compound
2. LCMS/APCI of G gave a pseudomolecular ion peak at m/z
396.10 [M+H]+, appropriate for
C
a
molecular formula of
23H25NO5. A multiplet in the 1H NMR spectrum at dH 3.66 with
an integral area of four protons is assigned to the H-6000 and H-2000

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S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
When compound 1 was reacted with thiosemicarbazide in
2.2. Biological evaluation
MeOH, the product was compound M. The molecular formula of
compound M was established as C20H19O4N3S by LCMS/APCI mass
spectrum (398.05 [M+H]+, 307.0 [Mꢀ(H2N–CS–NH–N)ꢀH]+, 308.0
[Mꢀ(H2N–CS–NH–N)]+). The IR spectrum of compound M showed
a stretching band of C@S at 1262 cmꢀ1 and the absorption bands of
–NH2 group at 3417 and 3263 cmꢀ1, its 1H NMR spectrum showed
the signal of H-300 at dH 7.45 (1H, t) instead of dH 9.85 in compound
110 and –C@SNH signal was displayed at dH 11.03. In the 13C NMR
spectra, the signals belonging to –N@CH and NH2C@S appeared at
dC 147.43 and 178.3, respectively. Therefore, compound M estab-
lished as 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]
propanal thiosemicarbazone.
A hydroxylamine hydrochloride (NH2OHꢂHCl) and sodium ace-
tate in acetonitrile undergo a reaction with compound 1 to give
N as a product. In the IR spectrum of compound N a broad OH
absorption peak was observed between 3428 and 3419 cmꢀ1. In
the 1H NMR spectra, the signals belonging to HC@N– and @N–
OH appeared at dH 6.69 and 10.78, respectively. In the 13C NMR
spectra of compound N, C@N signal was displayed at dC 150.42
while C@O signal disappeared. Thus, the structure of compound
N was determined as 3-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-ben-
zofuran-5-yl] propanal oxime.
In order to obtain the Wittig product, compound 1 reacted with
the Wittig reagent [1-(triphenylphosphoranylidene) acetone;
PPh3@CHCOCH3] in THF and afforded compound O. The molecular
formula C22H20O5 was deduced from LCMS/APCI 365.0 [M+H]+,
307.0 [Mꢀ(CH3–CO–C)ꢀ2H]+, 279.0 [Mꢀ(CH3–CO–C@CH–C)ꢀH]+,
1H and 13C NMR spectroscopic data. The signals belonging to car-
bonyl carbon and methyl carbon of acetyl group were seen at dC
197.46 and 33.59, respectively, in the 13C NMR spectrum of com-
pound O. In the 1H NMR spectrum, the singlet at dH 2.15, which
corresponds carbonyl bonded methyl group, and two olefinic pro-
tons at dH 6.75 and 6.06 proved the formation of Wittig product
and led to compound 6-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-ben-
zofuran-5-yl] hex-3-en-2-one.
The reaction of compound 1 and KOH in THF gave the aldol
product (compound P). The olefinic proton signal at dH 6.45 in
the 1H NMR spectrum and olefinic carbon signals at dC 143.31
and 155.35 in the 13C NMR spectrum were exhibited the formation
of condensation product. Thus, the structure of compound P was
determined as 5-[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofu-
ran-5-yl]-2-{[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-
yl]methyl}pent-2-enal with molecular formula C38H30O9.
Egonol and its derivatives were evaluated for their antimicro-
bial activities against Staphylococcus aureus ATCC 29213, Bacillus
subtilis ATCC 6633, Candida albicans ATCC 10231 and Escherichia
coli ATCC 8739 microorganisms using a standard Muller Hilton
Broth (MHB) method. Stock solution of all compounds was pre-
pared in DMSO. The minimum inhibitory concentration (MIC in
lg/mL) was determined for each compound. All results are pre-
sented in Table 1.
The obtained data reported that compound B exhibited im-
proved activities against all tested bacteria than egonol. While
the compounds F, G, L, P and R were found to be the most active
against C. albicans, aldol condensation product of egonol (com-
pound P) was found to the most active derivative against S. aureus
with values of 25
also showed noticeable activity against C. albicans showing MIC
values between 200 and 50 g/mL.
lg/mL. Compounds A, B, D, E, J, K, M, O and Q
l
Among compounds A, D, E, N, and O were inactive against all
tested microorganisms except C. albicans, indicating that the intro-
duction at C-30 groups different from the hydroxyl substituent was
in general detrimental for the antibacterial activity, but positive for
antifungal activity except compound C. Regarding compound C, the
results showed that substitution of C-30 hydroxyl group with sul-
fonic acid moiety increased activity against all tested bacteria
other than S. aureus, which remained the same. In case of
compound B, keeping the hydroxyl group at C-30 fixed and bearing
–NO2 groups at 3-, 6-positions led to an improvement of the MIC
values. On the other hand reduction of –NO2 group at C-3, as in
compound H, caused loss of activity except against C. albicans.
3. Experimental
3.1. General
The 1D and 2D NMR spectra were measured in CDCl3 at
400 MHz for 1H NMR and 100 MHz for 13C NMR on a Varian AS-
400 spectrometer. LC–MS was recorded on an AGILENT 1100MSD
spectrometer and FAB-MS was obtained using a zapSpec FAB (+)
spectrometer. CC and PTLC were carried out on Si Gel 60 Merck
7734 and 5554. TLC was carried out on Si Gel 60 F254 aluminium
plates (Merck 5554).
Table 1
The reaction of compound N with benzoyl chloride in dried THF
gave compound Q, whose molecular formula is C26H21NO6 and the
molecular ion peak was at m/z 442 [MꢀH]+. The characteristic
monosubstituted aromatic ring signals in the 1H NMR (dH 7.35,
7.45 and 8.02) and 13C NMR spectra (dC 130.37, 132.82 and
123.59) showed the oxime hydroxyl group was converted to aro-
matic ester. Furthermore, this conversion was also supported by
carbonyl peak at 1719 cmꢀ1 in the IR spectrum. Therefore, com-
pound Q was established as 3-[2-(1,3-benzodioxol-5-yl)-7-meth-
oxy-1-benzofuran-5-yl] propanal O-benzoyloxime.
Compound R was obtained from the reaction of compound N
with chloroacetyl chloride. The LCMS/APCI spectrum of R (m/z
416 [M]+) supported a molecular formula of C21H18ClNO6. The
major ion peak at m/z 307.0 was assigned to [Mꢀ(Cl–CH2–
COON)+H]+. The formation of chloroacetyl ester was proved by
the absorption peak at 1651 cmꢀ1 (C@O) and signals displayed
at dC 166.31 (C@O), 43.96 (–CH2Cl) in the 13C NMR spectra
besides the extra 1H NMR signal at dH 4.17 (–CH2Cl). Thus,
Antimicrobial activity of egonol and synthesised compounds (in DMSO)
Compound
S. aureusa
B. subtilisa
C. albicansa
E. colia
Egonol
800
800
25
100
50
400
200
200
25
800
*
*
*
A
B
C
D
E
F
G
H
I
400
400
400
800
400
400
*
*
*
*
*
*
*
*
*
*
*
800
*
200
25
*
*
800
*
*
800
*
J
K
L
M
N
O
P
Q
R
400
400
800
400
200
50
25
200
800
200
25
100
25
*
*
*
*
*
*
*
200
*
*
*
*
400
*
*
*
25
*
400
*
*
800
the structure of compound
R was established as 3-[2-(1,3-
a
benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl] propanal O-(2-
chloroacetyl)oxime.
MIC (
lg/mL), minimum inhibition concentration.
*
Not active.

Table 2
1H NMR data (J in Hz) of egonol and compounds A–I (400 MHz, d ppm, in CDCl3)
Position
Egonol
Compound
A
B
C
D
E
F
G
H
I
3
4
6.81, s, 1H
6.99, s, 1H
6.78, s, 1H
6.94, s, 1H
6.89, s, 1H
6.94, s, 1H
—
6.78, s, 1H
6.95, s, 1H
6.77, s, 1H
6.94, d, 1H,
J = 1.6
—
6.86, s, 1H
7.24, s, 1H
—
6.77, s, 1H
6.94, s, 1H
7.78, s, 1H
7.57, s, 1H
7.43, s, 1H
6
6.66, s, 1H
6.59, s, 1H,
J = 0.8
6.73, s, 1H
—
6.60, s, 1H
6.62, d, 1H,
J = 1.2
6.77, s, 1H
6.53, s, 1H
6.51, s, 1H
6.59, d, 1H
20
50
60
7.34, d, 1H,
J = 1.5
6.90, d, 1H,
J = 8.1
7.43, dd, 1H,
J = 1.6, 8.1
6.02, s, 2H
2.81, t, 2H,
J = 7.5, 7.8
1.97, p, 2H
3.73, t, 2H,
J = 6.4, 6.4
4.05, s, 3H
7.31, d, 1H,
J = 1.6
6.87, d, 1H,
J = 8.4
7.30, d, 1H,
J = 1.6
6.88, d, 1H,
J = 8.4
7.39, dd, 1H,
J = 1.6, 1.6
5.99, s, 2H
2.79, t, 2H,
J = 7.2, 8.0
2.02, p, 2H
4.06, t, 2H,
J = 6.4, 6.4
4.00, s, 3H
7.47, d, 1H,
J = 1.6
7.00, d, 1H,
J = 8.4
7.64, dd, 1H,
J = 1.6, 8.0
6.11, s, 2H
2.82, t, 2H,
J = 7.6, 8.0
1.96, p, 2H
3.71, t, 2H,
J = 6.4, 6.0
4.30, s, 3H
7.31, d, 1H,
J = 1.6
6.87, d, 1H,
J = 8.4
7.40, dd, 1H,
J = 1.6, 1.6
5.99, s, 2H
2.76, t, 2H,
J = 7.2, 8.0
2.03, p, 2H
4.13, t, 2H,
J = 6.4, 6.8
4.03, s, 3H
7.31, d, 1H,
J = 1.6
6.87, d, 1H,
J = 8.4
7.40, dd, 1H,
J = 1.6, 8.0
5.99, s, 2H
2.87, m, 2H,
J = 8.0, 8.0
2.14, p, 2H
2.77, t, 2H,
J = 7.2, 7.2
4.03, s, 3H
7.50, d, 1H,
J = 2.0
6.95, d, 1H,
J = 8.4
7.64, dd, 1H,
J = 1.6, 2.0
6.07, s, 2H
2.93, t, 2H,
J = 7.6, 7.6
2.19, p, 2H
3.58, t, 2H,
J = 6.0, 6.8
4.02, s, 3H
6.70, 1H, J = 1.6
6.55, d, 1H,
J = 1.6
6.84, d, 1H,
J = 8.8
7.45, dd, 1H,
J = 2.0, 7.6
5.97, s, 2H
2.55, t, 2H,
J = 7.2, 8.0
1.78, p, 2H
3.57, t, 2H,
J = 6.0, 6.8
3.83, s, 3H
7.31, d, 1H,
J = 1.6
6.87, d, 1H,
J = 8.4
7.40, dd, 1H,
J = 1.6, 1.6
6.00, s, 2H
2.75, t, 2H,
J = 7.2, 8.0
2.03, p, 2H
4.20, t, 2H,
J = 6.8, 6.8
4.03, s, 3H
6.79, d, 1H,
J = 8.4
7.40, dd, 1H,
J = 1.2, 1.6
5.99, s, 2H
2.78, t, 2H,
J = 7.6, 7.6
2.08, p, 2H
4.25, t, 2H,
J = 6.4, 6.4
4.03, s, 3H
4.05, s, 2H
7.32, dd, 1H,
J = 0.8, 7.2
5.91, s, 2H
2.33, t, 2H,
J = 7.6, 7.6
1.81, p, 2H
2.64, t, 2H,
J = 6.8, 6.4
3.94, s, 3H
–OCH2O–
100
200
300
–OMe
Cl–CH2–
CH3–C@O
CH3CH2N–
2.13, s, 3H
1.27, t, 6H,
J = 7.2, 2.8
2.98, q, 4H
CH3CH2N–
–NCH2CH2O–
2.38, t, 4H
3.66, t, 4H
2.60, t, 4H,
J = 4.8, 4.4
3.76, t, 4H,
J = 4.8, 4.8
–NCH2CH2O–
–NH2
1.58, s, 2H
–CH2COO–
3.20, s, 2H

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S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
3.2. Plant material
the homogeneous slurry and the mixture was cooled at 0 °C with
vigorous stirring. A solution of egonol (163 mg, 5.00 ꢁ 10ꢀ4 mol)
in CH2Cl2 was added drop wise to the solution, and then, stirred
at room temperature for the required time. The reaction mixture
was washed twice with 10% aqueous Na2HCO3 and then organic
phase was dried over anhydrous sodium sulfate, filtered and con-
centrated to dryness. The residue was purified by PTLC using hex-
ane/EtOAc/H2O (6:4:0.5) to afford C (24 mg, 11,5%); mp: 188.7–
189.0 °C; UV kmax CH2Cl2: 229.0, 269.0, 384.0 nm; IR spectrum mmax
CH2Cl2 cmꢀ1: 3664, 3642, 3354, 3109, 2924, 2853, 2335, 1882,
1736, 1698, 1605, 1543, 1507, 1467, 1439, 1354, 1320, 1277,
1230, 1144, 1099, 1056, 1032, 960, 910, 876, 821, 765, 688, 674;
LCMS/APCI m/z (rel. int.): 416.10 [M]+ (0.2), 403.0 [Mꢀ(OH)+3H]+
(100), 327.05 [Mꢀ2ꢁ(NO2)+H]+ (15.4); 1H and 13C NMR data are
presented in Tables 2 and 4.
Fruits of S. officinalis L. were collected from Aydın, Turkey in
September 2005. A voucher specimen was deposited in the Herbar-
ium of Ege University (EGE 4759).
3.3. Extraction
Air-dried and powdered plant material of 241 g. S. officinalis was
extracted with n-hexane at room temperature. After filtration, the
solvent was removed by rotary evaporation to give a crude extract
(113.72 g). An aliquot of the crude was hydrolysed with 33% KOH
at 100 °C for 3 h. The reaction mixture was collected and extracted
with CH2Cl2, then the organic phase was subjected into Si-gel CC to
afford egonol. The identification of the achieved 6 g egonol was
done by 1H and 13C NMR.
3.4.4. Compound D
3.4. Synthesis
3.4.4.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]propyl acetate (C21H20O6). To a mixture of egonol (50 mg,
1.53 ꢁ 10ꢀ4 mol) and THF (5 mL) were added acetic anhydride
(14.5 mL) and AlCl3 (20 mg, 1.50 ꢁ 10ꢀ4 mol). After stirring at
0 °C for 1 h, the mixture was allowed to stir for an additional
48 h at room temperature. After addition of a solution of HCl (1%,
10 mL), the mixture was extracted with CH2Cl2 (3 ꢁ 10 mL). And
then the CH2Cl2 phase was extracted with NaHCO3 solution (10%;
3 ꢁ 10 mL). The organic layer was dried (Na2SO4) and concentrated
to yield D (48.5 mg, 85.9%): (mp 85.9–87.0 °C; LCMS/APCI m/z (rel.
int.): 368 [M]+, 279.0 [Mꢀ(CH3–COO–CH2–CH2)ꢀ2H]+ (1.1); UV
3.4.1. Compound A
3.4.1.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]propyl chloroacetate (C21H19ClO6). To a solution of egonol
(100 mg, 3.06 ꢁ 10ꢀ4 mol) in dry Et2O (5 mL) in a round bottomed
two-necked flask was added Et3N (10.5 mg, 1.04 ꢁ 10ꢀ4 mol). The
reaction mixture was stirred at room temperature under Ar for
30 min. After cooling to 0 °C, the mixture was stirred for a further
1 h while purging with Ar. A solution of chloroacetyl chloride
(13.19 mg, 1.16 ꢁ 10ꢀ4 mol) in dry Et2O (5 mL) was added to the
reaction flask and stirred for 15 min at 0 °C. After leaving 96 h, a
solution of NaHCO3 (10%) was added into reaction flask. The aque-
ous solution was extracted with Et2O (3 ꢁ 10 mL). The combined
organic layers were dried (Na2SO4) and evaporated to dryness.
The residue was purified via column chromatography on silica
gel using hexane/EtOAc (10:1) as an eluent to yield A (74.2 mg,
60.1%); mp: 111.4 °C; UV kmax CH2Cl2: 230.0, 318.0 nm; IR spec-
trum mmax CH2Cl2 cmꢀ1: 3741, 3648, 2934, 2668, 1750, 1643,
1585, 1500, 1412, 1325, 1229, 1122, 1033, 1009, 825, 696; LCMS/
APCI m/z (rel. int.): 405.0 [M]+ (17.0), 403.0 [M]+ (48.5), 327
[Mꢀ(Cl–CH2–C@O)+H]+ (11.7); 1H and 13C NMR data are presented
in Tables 2 and 4.
kmax CH2Cl2: 230.0, 318.0 nm; IR spectrum mmax CH2Cl2 cmꢀ1
:
3453, 2923, 2852, 2043, 1736, 1620, 1600, 1503, 1477, 1449,
1386, 1366, 1334, 1233, 1145, 1116, 1039, 995, 962, 930, 871,
819, 742, 722, 696, 649, 605, 512, 459; 1H and 13C NMR data are
presented in Tables 2 and 4.
3.4.5. Compound E
3.4.5.1. {3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]propyl}diethylamine (C23H27NO4).
5-[300-Chloropropyl]-7-
methoxy-2-(30,40-methylenedioxyphenyl) benzofuran (compound
2)10 (40 mg, 1.16 ꢁ 10ꢀ4 mol) was added to a mixture of diethyl-
amine (20 mL) in chloroform (3 mL) and stirred for 96 h at room
temperature. The reaction mixture was diluted with water
(10 mL) and extracted with CH2Cl2 (3 ꢁ 7 mL). The organic layer
was dried over anhydrous sodium sulfate and evaporated to dry-
ness. The residue was purified by PTLC using hexane/EtOAc (9:2)
to gave E (22.0 mg, 49.7%); mp 127.0–128.0 °C; LCMS/APCI m/z
(rel. int.): 382.10 [M+H]+ (100), 383.10 [M+2H]+ (24.3), 354.10
[Mꢀ(2ꢁCH3)+3H]+ (4.8), 307 [Mꢀ(N(CH3CH2)2)+2H]+ (3.5); UV
3.4.2. Compound B
3.4.2.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]propyl hydrogen sulfate (C19H18O8S). Concentrated H2SO4
(3 mL) was added slowly to
a solution of egonol (150 mg,
4.60 ꢁ 10ꢀ4 mol) in a acetonitrile/CH2Cl2 (10 mL:2 mL). The solu-
tion was stirred for 2 h at 0 °C and for an additional 16 h at room
temperature. Organic solvents were then removed and water
(10 mL) was added to the mixture and then extracted with n-BuOH
(3x10 mL). n-BuOH phase was neutralized with NaHCO3 (10%,
10 mL) and the water layer extracted with CH2Cl2 (3 ꢁ 10 mL).
The combined organic layers were evaporated to dryness. The res-
idue was purified by column chromatography on silica gel using
CH2Cl2 to afford B (75.7 mg, 40.5%); mp: 180 °C (dec); UV kmax
MeOH: 217.0, 316.0; IR spectrum mmax MeOH cmꢀ1: 3666, 2966,
2923, 1599, 1473, 1448, 1231, 1214, 1054, 1013, 927; LCMS/APCI
m/z (rel. int.): 406.0 [M]+ (0.8), 327 [Mꢀ(HO–SO2)+2H]+ (9.1), 403
[Mꢀ3H]+ (50.3); 1H and 13C NMR data are presented in Tables 2
and 4.
kmax CH2Cl2: 230.0, 319.0 nm; IR spectrum mmax CH2Cl2 cmꢀ1
:
3736, 3642, 2928, 2851, 2642, 2318, 2000, 1736, 1662, 1621,
1500, 1470, 1443, 1363, 1273, 1259, 1234, 1209, 1523, 1105,
1034, 927, 814, 762, 749, 691; 1H and 13C NMR data are presented
in Tables 2 and 4.
3.4.6. Compound F
3.4.6.1. 5-(300-Chloropropyl)-7-methoxy-3-nitro-2-(30,40methy-
lene dioxyphenyl)benzofuran (C19H16ClNO6). KNO3 (112 mg,
1.10 ꢁ 10ꢀ3 mol) and 96% H2SO4 (0.3 mL) was stirred for 15 min
at 0 °C. After addition of CH2Cl2 (7 mL), a solution of compound 2
(40 mg, 1.16 ꢁ 10ꢀ4 mol) in CH2Cl2 (3 mL) was slowly added to
the mixture and stirred for 48 h at room temperature. Water
(10 mL) was added to the mixture and then extracted with CH2Cl2
(3 ꢁ 10 mL). The organic layer was dried over anhydrous sodium
sulfate and evaporated to dryness. The obtained residue was puri-
fied via column chromatography on silica gel using hexane/EtOAc
(9:1) to afford F (23.0 mg, 50.9%); mp: 137.3–138.3 °C; LCMS/
APCI m/z (rel. int.): 391.2 [M+H]+ (15.3), 392.2 [M]+ (5.3), 341.0
3.4.3. Compound C
3.4.3.1.
5-[300-Hydroxypropyl]-7-methoxy-3,6-dinitro-2-
(30,40methylene dioxyphenyl) benzofuran (C19H16N2O9). Pow-
dered KNO3 (50.5 mg, 5.00 ꢁ 10ꢀ4 mol) was treated with the
appropriate amount of H2SO4 (96%, 1 mL) and the mixture was stir-
red for 15 min at room temperature. CH2Cl2 (25 mL) was added to

S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
1185
[Mꢀ(Cl–CH2)]+ (4.5), 327.05 [Mꢀ(Cl–CH2–CH2)]+ (5.6); UV kmax
CH2Cl2: 228.0, 268.0, 381.0 nm; IR spectrum mmax CH2Cl2 cmꢀ1
:
3680, 2972, 2512, 2844, 1738, 1473, 1346, 1259, 1215, 1054,
1013, 765, 750; 1H and 13C NMR data are presented in Tables 2
and 4.
3.4.7. Compound G
3.4.7.1. 4-{3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofu-
ran-5-yl]propyl}morpholine (C23H25NO5). To a solution of com-
pound 2 (40 mg, 1.16 ꢁ 10ꢀ4 mol) in toluene (7 mL) was added
morpholine (5.11 ꢁ 10ꢀ3 mg, 5.87 ꢁ 10ꢀ5 mol) and the mixture
was heated under reflux for 40 h. Water (10 mL) was added to
the resulting mixture and extracted with CH2Cl2 (3 ꢁ 7 mL). The
organic phase was dried over anhydrous sodium sulfate and evap-
orated to dryness. 38.5 mg compound was obtained (83.9%); LCMS/
APCI m/z (rel. int.): 396.10 [M+H]+ (100), 397.1 [M+2H]+ (23.4),
307.05 [Mꢀ(O–(CH2CH2)2N)ꢀ2H]+ (2.7); UV kmax CH2Cl2: 233,
318 nm; IR spectrum mmax CH2Cl2 cmꢀ1: 2924, 2854, 1620, 1600,
1550, 1503, 1476, 1449, 1365, 1332, 1263, 1232, 1214, 1144,
1116, 1070, 1038, 929, 861, 819, 741, 602, 512, 479, 459; 1H and
13C NMR data are presented in Tables 2 and 4.
3.4.8. Compound H
3.4.8.1.
5-[300-Hydroxypropyl]-7-methoxy-3-amino-2-
(30,40methylene dioxyphenyl) benzofuran (C19H19NO5). Two
milligrams of 10% Pd–C catalyst was added to a solution of 5-[300-
hydroxypropyl]-7-methoxy-3-nitro-2-(30,40-methylenedioxy-
phenyl)benzofuran (compound 8)10 (29 mg, 7.81 ꢁ 10ꢀ5 mol) in
EtOH (3 mL) while stirring under Ar atmosphere and heated to
65 °C. A solution of hydrazine monohydrate (1 mL) in EtOH
(3 mL) was slowly added into a flask and stirred for 24 h at room
temperature while purging with Ar. Pd–C was filtered off, then
the solvent was evaporated under vacuum. The crude product
was eluted through an alumina column with CH2Cl2/MeOH
(10:1) to afford compound H as an amorphous powder (11.7 mg,
43.9% yield); LCMS/APCI m/z (rel. int.): 345.10 [M+4H]+ (37.7),
327.0 [Mꢀ(NH2)+2H]+ (40.2); UV kmax CH2Cl2: 230.0, 279.0,
311.0 nm; IR spectrum mmax CH2Cl2 cmꢀ1: 3478, 3329, 2924,
2857, 2346, 1731, 1676, 1593, 1501, 1443, 1355, 1273, 1259,
1229, 1146, 1075, 1037, 930, 809, 765, 750; 1H and 13C NMR data
are presented in Tables 2 and 4.
3.4.9. Compound I
3.4.9.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]propyl morpholin-4-ylacetate (C25H27NO7). A mixture of
compound A (40 mg, 9.93 ꢁ 10ꢀ5 mol) and morpholine (3.72 ꢁ 10
ꢀ3 mg, 4.28 ꢁ 10ꢀ5 mol) in THF (5 mL) was refluxed with stirring
for 10 h. The reaction mixture was diluted with water (10 mL)
and then extracted with CH2Cl2 (3 ꢁ 7 mL). The organic phase
was dried over anhydrous sodium sulfate and evaporated to dry-
ness. Compound
I was obtained as an amorphous powder
(37.3 mg, 82.8% yield); LCMS/APCI m/z (rel. int.): 454.10 [M+H]+
(100), 455.10 [M+2H]+ (27.0), 327.10 [Mꢀ(O–(CH2CH2)2N–CH2–
CO)+H]+ (19.6); UV kmax CH2Cl2: 231, 318 nm; IR spectrum mmax
CH2Cl2 cmꢀ1: 2919, 1744, 1599, 1476, 1365, 1232, 1146, 1115,
1036, 929, 868, 820; 1H and 13C NMR data are presented in Tables
2 and 4.
3.4.10. Compound J
3.4.10.1.
3-[2-(3,4-Dimethoxyphenyl)-7-methoxy-1-benzofu-
ran-5-yl]propyl chloroacetate (C22H23ClO6). A solution of tri-
methoxy egonol (100 mg, 3.06 ꢁ 10ꢀ4 mol) and triethylamine
(10.5 mg, 1.04 ꢁ 10ꢀ4 mol) in dry diethyl ether (5 mL) was stirred
for 30 min at room temperature under Ar atmosphere. The solution
was cooled at 0 °C and stirred for a further 2 h while purging with
Ar. Chloroacetyl chloride (13.19 mg, 1.16 ꢁ 10ꢀ4 mol) in dry

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S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
diethyl ether (5 mL) was added to the mixture. After stirring for
15 min at 0 °C, the mixture was warmed to room temperature
and stirred for a further 96 h. The reaction was quenched by addi-
tion of aqueous NaHCO3 solution and the mixture was extracted
with diethyl ether (3 ꢁ 10 mL). The ether phase was dried over
anhydrous sodium sulfate, evaporated to dryness and the solid
was purified via column chromatography on silica gel by using
hexane/EtOAc (10:1) to give J (10.6 mg; 8.7%). Mp: 63 °C; UV kmax
CH2Cl2: 230.0, 315.0 nm.; IR spectrum mmax CH2Cl2 cmꢀ1: 3424,
2922, 2851, 1731, 1708, 1598, 1510, 1463, 1250, 1140, 1023,
932, 853, 741; LCMS/APCI m/z (rel. int.): 419.10 [M]+ (11.5),
421.10 [M]+ (4.1), 369.0 [Mꢀ(Cl–CH2)]+ (1.3); 1H and 13C NMR data
are presented in Tables 3 and 5.
(3 ꢁ 10 mL). The organic layer was dried over anhydrous sodium
sulfate and concentrated. Column chromatography on silica gel
(CH2Cl2) afforded L (29.4 mg; 25.0%); mp: 200.2 °C; UV kmax MeOH:
220.0, 316.0 nm.; IR spectrum m
max MeOH cmꢀ1: 3466, 3196, 2923,
2853, 1698, 1582, 1475, 1439, 1372, 1271, 1232, 1218, 1127, 1040,
929, 766, 743, 633; LCMS/APCI m/z (rel. int.): 380.0 [M+H]+, 354.0
[Mꢀ(NH2C)+H]+ (8.3), 307 [Mꢀ(NH2CONHN)+H]+ (100); 1H and 13
C
NMR data are presented in Tables 3 and 5.
3.4.13. Compound M
3.4.13.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] propanal thiosemicarbazone (C20H19N3O4S). A solution of
thiosemicarbazide (30 mg, 3.29 ꢁ 10ꢀ4 mol) in water (7 mL) was
added to a solution of compound 1 (77 mg, 2.37 ꢁ 10ꢀ4 mol) in
MeOH (7 mL). The mixture was refluxed for 1 h and then stirred
at room temperature for 48 h. Water (10 mL) was added to the
reaction mixture and extracted with CH2Cl2 (3 ꢁ 10 mL). The or-
ganic layer was dried over anhydrous sodium sulfate and evapo-
rated to dryness. The residue was chromatographed on silica gel
using CH2Cl2/MeOH (20:1) to give M (27 mg; 28.6%); mp: 181.7–
182.5 °C; UV kmax CH2Cl2: 216.0, 274.0, 316.0 nm.; IR spectrum
mmax CH2Cl2 cmꢀ1: 3417, 3263, 3159, 3000, 2923, 2846, 2675,
2318, 2032, 1733, 1593, 1525, 1497, 1478, 1445, 1360, 1262,
1229, 1209, 1144, 1111, 1034, 993, 927, 861, 812, 768, 749, 581;
LCMS/APCI m/z (rel. int.): 398.05 [M+H]+ (10.3), 307.0 [Mꢀ(H2N–
CS–NH–N)ꢀH]+ (57.5), 308.0 [Mꢀ(H2N–CS–NH–N)]+ (11.6); 1H
and 13C NMR data are presented in Tables 3 and 5.
3.4.11. Compound K
3.4.11.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] propanoic acid (C19H16O6). To a mixture of 3-[2-(1,3-ben-
zodioxol-5-yl)-7-methoxy-1-benzofuran-5-yl]propanal (compound
1)10 (61.5 mg, 1.90 ꢁ 10ꢀ4 mol) in acetone (9 mL), a solution of
H2O2 (30%, 24 mL) was added and the mixture was stirred for
120 h at room temperature. Acetone was distilled off, 10 mL water
was added and extracted with CH2Cl2 (3 ꢁ 10 mL). The organic
layer was dried over anhydrous sodium sulfate and evaporated
to dryness to give K (43.5 mg, 67.4%); mp: 148.2–149.0 °C; UV kmax
MeOH: 216.0, 316.0 nm.; IR spectrum mmax MeOH cmꢀ1: 3738,
2978, 2862, 1733, 1681, 1454, 1363, 1209, 1054, 1033, 1009;
LCMS/APCI m/z (rel. int.): 341.0 [M+H]+ (100), 342.0 [M+2H]+
(19.0), 323 [MꢀOH]+ (3.5); 1H and 13C NMR data are presented in
Tables 3 and 5.
3.4.14. Compound N
3.4.14.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] propanal oxime (C19H17NO5). A mixture of the compound 1
3.4.12. Compound L
3.4.12.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] propanal semicarbazone (C20H19N3O5). A solution of semi-
carbazide (32 mg, 4.00 ꢁ 10ꢀ4 mol) in water (7 mL) was added to a
solution of compound 1 (100 mg, 3.08 ꢁ 10ꢀ4 mol) in MeOH (7 mL)
under stirring. The mixture was kept a reflux for 1.5 h and then
cooled to room temperature. After stirring overnight, water
(10 mL) was added to the mixture and extracted with CH2Cl2
(100 mg,
3.08 ꢁ 10ꢀ4 mol),
hydroxylamine
hydrochloride
(NH2OHꢂHCl) (5.5 mg, 7.94 ꢁ 10ꢀ5 mol) and sodium acetate
(9.6 mg, 1.17 ꢁ 10ꢀ4 mol) were dissolved in acetonitrile (6 mL)
and water (2 mL). The solution was stirred at room temperature
for 24 h. Acetonitrile was evaporated. After addition of 10 mL
water, the mixture was extracted with CH2Cl2 (3 ꢁ 10 mL). The or-
ganic layer was dried over anhydrous sodium sulfate and concen-
Table 4
13C NMR data of egonol and compounds A–C, and E–I (100 MHz, d ppm, in CDCl3)
Position
Egonol
Compound
A
B
C
E
F
G
H
I
2
3
3a
4
5
6
7
7a
156.51
100.76
131.46
112.72
137.92
107.86
145.20
142.88
101.71
125.12
105.95
148.46
148.39
109.02
119.62
32.83
156.45
100.55
131.38
112.60
136.74
107.69
145.11
142.82
101.54
124.90
105.79
148.31
148.27
108.84
119.47
30.66
155.81
102.11
131.14
112.79
138.45
108.56
145.01
142.32
101.76
124.75
105.65
148.64
148.47
109.50
119.42
31.56
156.94
125.51
132.80
115.58
132.80
140.38
142.10
137.20
102.39
120.20
109.91
151.62
148.28
108.92
126.09
28.13
156.58
100.51
131.45
112.57
135.92
107.48
145.28
142.93
101.55
124.80
105.79
148.33
148.33
108.86
119.51
33.52
156.91
140.48
139.85
112.92
123.84
109.74
147.96
145.09
102.11
121.21
110.12
150.83
150.83
108.62
125.79
33.54
156.31
100.58
131.24
112.51
137.94
107.78
144.97
142.71
101.51
124.98
105.77
148.29
148.21
108.83
119.43
29.91
163.12
168.32
131.58
122.43/122.68/122.92
132.30
107.97/108.23/110.68
148.13/148.75/149.59
143.64
156.43
100.54
131.36
112.56
136.95
107.68
145.09
142.80
101.53
124.90
105.78
148.31
148.26
108.84
119.46
30.86
–OCH2O–
101.59
10
122.43/122.68/122.92
107.97/108.23/110.68
148.13/148.75/149.59
148.13/148.75/149.59
107.97/108.23/110.68
122.43/122.68/122.92
34.46
20
30
40
50
60
100
200
35.08
62.70
32.51
65.74
32.02
67.30
33.87
62.04
26.05
51.12
34.57
44.31
34.14
56.39
31.80
62.31
32.14
64.31
300
–OMe
56.57
56.45
55.48
61.95
56.58
56.45
58.55
56.09
59.87
–COO
167.56
41.10
Cl–CH2–
CH3CH2N–
CH3CH2N–
–NCH2CH2O–
–NCH2CH2O–
–CH2COO–
–C@O
9.34
46.75
53.93
67.15
53.53
67.01
56.45
170.36

S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
1187
Table 5
13C NMR data of compounds K–O, Q, and R (100 MHz, d ppm, in CDCl3)
Position
Compound
K
L
M
N
O
Q
R
2
3
3a
4
5
6
7
7a
155.89
102.12
131.14
112.73
137.72
108.43
145.01
142.41
101.74
124.69
105.66
148.64
148.51
109.50
119.43
31.50
155.86
101.69
131.15
112.91
137.90
108.48
144.94
142.31
102.09
124.61
105.56
148.59
148.47
109.56
119.49
32.87
155.93
101.74
131.19
112.87
137.77
108.60
145.03
142.38
102.13
124.69
105.68
148.65
148.52
109.51
119.45
32.67
155.922
101.74
131.20
112.73
137.90
108.34
145.08
142.42
102.12
124.68
105.66
148.64
148.51
109.50
119.44
32.40
155.25
99.33
132.10
111.29
135.38
106.43
143.87
141.63
100.30
123.64
104.54
146.07/147.08
146.07/147.08
107.62
118.25
25.92
155.51
100.34
131.73
111.45
141.61
107.63
144.10
143.91
104.54
127.41
106.12
147.15
147.09
111.23
118.31
28.67
155.50
99.34
130.37
111.48
132.90
107.64/106.41
144.12
142.03
100.37
123.46
106.41
147.17
147.13
107.64/106.41
118.32
30.95
–OCH2O–
10
20
30
40
50
60
100
200
36.67
—
56.49
34.38
—
56.46
34.48
—
56.51
27.29
150.42
56.49
33.59/33.79
130.18/130.91
55.23
30.93
204.02
55.24
39.89
166.26
55.27
166.31
43.96
300
–OMe
–C@O
Cl–CH2–
–COOH
–NH–C@O
NH2–C@O
NH2–C@S
–CH–C@O
–CH3
A
197.46
212.47
174.63
144.39/144.94
144.39/144.94
147.43
178.33
25
130.18/130.91
33.59/33.79
200.73
123.59
130.37
132.82
B
C
D
trated. Compound (100 mg) was obtained (95.7%). Mp: 150.0–
153.0 °C; UV kmax MeOH: 230.0, 319.0 nm.; IR spectrum mmax
MeOH cmꢀ1: 3428 (OH stretching), 2082, 1640, 663; LCMS/APCI
m/z (rel. int.): 307.05 [Mꢀ(OH–N)ꢀH]+ (3.5), 279.0 [Mꢀ(OH–
N@CH–C)]+ (23.0); 1H and 13C NMR data are presented in Tables
3 and 5.
The residue was purified by PTLC using hexane/EtOAc/H2O
(6:4:0.5) to give P (16 mg, 16.5%). Mp: 85.0–87.0 °C; UV kmax
CH2Cl2: 230.0, 319.0 nm.; IR spectrum mmax CH2Cl2 cmꢀ1: 3010,
2923, 2846, 2719, 1731, 1681, 1621, 1599, 1502, 1476, 1448,
1364, 1330, 1260, 1232, 1143, 1114, 1038, 987, 929, 871, 815,
751; 1H and 13C NMR data are presented in Table 6.
3.4.15. Compound O
3.4.17. Compound Q
3.4.15.1. 6-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] hex-3-en-2-one (C22H20O5). To a solution of compound 1
(22 mg, 6.78 ꢁ 10ꢀ5 mol) in THF (7 mL) was added PPh3@CHCOCH3
(25.5 mg, 8.0 ꢁ 10ꢀ5 mol) and the mixture was refluxed for 10 h
then allowed to cool. The mixture was hydrolysed with 10% HCl
solution and then neutralized with a 5% solution of NaOH. The res-
idue was extracted with CH2Cl2 (3 ꢁ 7 mL) and CH2Cl2 phase dried
over anhydrous sodium sulfate, filtered and evaporated to dryness
to give O as an amorphous powder (21.3 mg, 86.2%); UV kmax
CH2Cl2: 230.0, 319.0 nm.; IR spectrum mmax CH2Cl2 cmꢀ1: 2960,
1668, 1478, 1433, 1260, 1184, 1118, 1021, 799, 749, 716, 540;
LCMS/APCI m/z (rel. int.): 365.0 [M+H]+ (1.8), 307.0 [Mꢀ(CH3–
CO–C)ꢀ2H]+ (11.0), 279.0 [Mꢀ(CH3–CO–C@CH–C)ꢀH]+ (100.0);
1H and 13C NMR data are presented in Tables 3 and 5.
3.4.17.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] propanal O-benzoyloxime (C26H21NO6). A solution of com-
pound N (60 mg, 1.77 ꢁ 10ꢀ4 mol) in dry THF (7 mL) was placed in
a 50 mL two-necked flask with a reflux condenser. Benzoyl chlo-
ride (15.2 mg, 1.09 ꢁ 10ꢀ4 mol) was added to the reaction mixture
and refluxed at 50 °C for 15 h under Ar atmosphere. Reaction mix-
ture was cooled and then 10% NaHCO3 solution (10 mL) was added.
The mixture was extracted with CH2Cl2 (3 ꢁ 10 mL) and CH2Cl2
phase was dried over anhydrous sodium sulfate, concentrated to
dryness to afford the product (77 mg, 98.2%). Mp: 126.0–
128.0 °C; UV kmax CH2Cl2: 230.0, 318.0 nm.; IR spectrum mmax
CH2Cl2 cmꢀ1: 3444, 2962, 2245, 1719 (C@O stretching), 1621,
1601, 1475, 1366, 1261, 1233, 1146, 1115, 1038, 929, 870, 802
(N–O stretching), 742, 601, 517; LCMS/APCI m/z (rel. int.): 442
[MꢀH]+ (5.7), 307 [Mꢀ(C6H5–CO–ON)ꢀH]+ (37.1), 279.0
[Mꢀ(C6H5–COON@CH–CH2)ꢀ2H]+ (23.4); 1H and 13C NMR data
are presented in Tables 3 and 5.
3.4.16. Compound P
3.4.16.1. 5-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl]-2-{[2-(1,3-benzodioxol-5-yl)-7-methoxy-1-benzofuran-5-
yl]methyl}pent-2-enal (C38H30O9). To a solution of compound 1
3.4.18. Compound R
(50 mg, 1.54 ꢁ 10ꢀ4 mol) in THF (5 mL),
a
solution of KOH
3.4.18.1. 3-[2-(1,3-Benzodioxol-5-yl)-7-methoxy-1-benzofuran-
5-yl] propanal O-(2-chloroacetyl)oxime (C21H18ClNO6). Com-
pound N (30 mg, 8.82 ꢁ 10ꢀ5 mol) and dry THF (7 mL) were placed
in a 50 mL two-necked flask with a reflux condenser. Chloroacetyl
chloride (4.95 mg, 4.38 ꢁ 10ꢀ5 mol) was added to the mixture and
refluxed at 50 °C for 13 h under Argon. Reaction mixture was
(20 mg, 3.57 ꢁ 10ꢀ4 mol) in water was added portion wise. The
reaction mixture was stirred at 0 °C for 6 h and then allowed to
stand at 4 °C overnight. After dilution with water (10 mL), the solu-
tion was extracted with CH2Cl2 (3 ꢁ 7 mL). The organic phase was
dried over anhydrous sodium sulfate and evaporated to dryness.

1188
S. Emirdag˘-Öztürk et al. / Bioorg. Med. Chem. 19 (2011) 1179–1188
Table 6
cooled and neutralized with NH3 solution. After addition of water
1H (J in Hz) and 13C NMR data of compound P
(10 mL), the mixture was extracted with CH2Cl2 (3 ꢁ 5 mL). The
organic phase was dried over anhydrous sodium sulfate and evap-
orated to dryness to afford R as an amorphous powder (31.1 mg,
84.6%). UV kmax CH2Cl2: 230.0, 318.0 nm; IR spectrum mmax CH2Cl2
cmꢀ1: 3626, 3444, 2098, 1651–1633 (C@O stretching), 1504, 1476,
1365, 1260, 1233, 1146, 1115, 1037, 928, 744 (N–O stretching),
766; LCMS/APCI m/z (rel. int.): 416 [M]+ (7.3), 355 [Mꢀ(Cl–CH2–
C)+H]+ (6.8), 322.0 [Mꢀ(Cl–CH2–CO–O)+H]+ (55.9), 307 [Mꢀ(Cl–
CH2–COON)+H]+ (100); 1H and 13C NMR data are presented in Ta-
bles 3 and 5.
Position
Compound P
d
1H
d
13C
2
3
3a
4
5
6
7
7a
—
156.30
100.52
131.20
112.43
134.95
107.62
145.00
142.76
101.52
124.80
105.73
148.26
148.20
108.81
119.42
35.00
6.57, s, 1H
—
6.66, s, 1H
—
6.43, d, 1H, J = 1.2
—
—
–OCH2O–
5.92, s, 2H
—
10
Acknowledgements
20
7.18, d, 1H, J = 2.0
30
—
—
This work was supported by TUBITAK (105T226), Ege University
Research Foundation (2005 Fen 047) and Ege University Science,
Technology Application and Research Center (2007 Bil 036). The
authors thank Professor Dr. Misir Ahmedzade for his valuable sug-
gestions for synthetic routes and also Assoc. Professor Dr. Yurdanur
AKGUL for her assistance in some of the NMR analyses.
40
50
6.76, d, 1H, J = 8.0
7.27, dd, 1H, J = 1.6, 4.8
60
100
3.58, s, 2H
—
9.41, s, 1H
3.88, s, 3H
200
143.31
194.92
56.39
300
–OMe
2000
—
156.48
100.59
131.42
112.55
136.30
107.86
145.10
142.86
101.54
124.89
105.75
148.29
148.20
108.84
119.47
31.68
3000
6.63, s, 1H
—
6.73, s, 1H
—
References and notes
3a0
4000
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6000
6.52, d, 1H, J = 1.6
7000
—
—
7a000
–OC0H2O–
10000
20000
30000
40000
50000
60000
100000
200000
300000
–OMe0
5.93, s, 2H
—
7.20, d, 1 H, J = 1.2
—
—
6.78, d, 1H, J = 4.0
7.29, dd, 1H, J = 2.0, 2.0
2.74, t, 2H
2.74, q, 2H
6.45, t, 1H
3.89, s, 3H
30.08
155.35
56.42