Microwave-induced synthesis and bioactivity of [3-Phenoxy-methyl-4-phenyl- 1,2,4-triazole-5-yl-thio]acetyl hydrazone derivatives

Article abstract of DOI:10.1080/10426500903463713

A convenient method for the preparation of hydrazone derivatives from condensation reaction of [3-phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio] acetyl hydrazine with various substituted benzaldehydes under conditions of microwave irradiation has been developed. This method has many merits including high yields, short reaction times, ease of work-up, and simple operation. All of the compounds have been characterized by 1H NMR, 13C NMR, IR spectra and elemental analysis. In addition, the preliminary biological activity tests showed that some of the title compounds remarkably enhanced the root elongation of rape seedings; moreover, some compounds possessed antibacterial activity against Bacillus subtilis. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500903463713

This article was downloaded by: [University of Cambridge]
On: 18 December 2014, At: 16:38
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Phosphorus, Sulfur, and Silicon and the
Related Elements
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/gpss20
Microwave-Induced Synthesis and
Bioactivity of [3-Phenoxy-methyl-4-
phenyl-1,2,4-triazole-5-yl-thio]acetyl
Hydrazone Derivatives
Tai-Bao Wei a , Xiao-Li Du a , Rong Xu a & You-Ming Zhang a
a College of Chemistry and Chemical Engineering, Key Laboratory of
Polymer Materials of Gansu Province , Northwest Normal University ,
Lanzhou, Gansu, P. R. China
Published online: 24 Sep 2010.
To cite this article: Tai-Bao Wei , Xiao-Li Du , Rong Xu & You-Ming Zhang (2010) Microwave-Induced
Synthesis and Bioactivity of [3-Phenoxy-methyl-4-phenyl-1,2,4-triazole-5-yl-thio]acetyl Hydrazone
Derivatives, Phosphorus, Sulfur, and Silicon and the Related Elements, 185:10, 2030-2035, DOI:
10.1080/10426500903463713
To link to this article: http://dx.doi.org/10.1080/10426500903463713
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the
“Content”) contained in the publications on our platform. However, Taylor & Francis,
our agents, and our licensors make no representations or warranties whatsoever as to
the accuracy, completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content
should not be relied upon and should be independently verified with primary sources
of information. Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising
out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Conditions of access and use can be found at http://www.tandfonline.com/page/terms-
and-conditions

Phosphorus, Sulfur, and Silicon, 185:2030–2035, 2010
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500903463713
MICROWAVE-INDUCED SYNTHESIS AND BIOACTIVITY
OF [3-PHENOXY-METHYL-4-PHENYL-1,2,4-TRIAZOLE-5-YL-
THIO]ACETYL HYDRAZONE DERIVATIVES
Tai-Bao Wei, Xiao-Li Du, Rong Xu, and You-Ming Zhang
College of Chemistry and Chemical Engineering, Key Laboratory of Polymer
Materials of Gansu Province, Northwest Normal University, Lanzhou,
Gansu, P. R. China
A convenient method for the preparation of hydrazone derivatives from condensation re-
action of [3-phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio]acetyl hydrazine with various
substituted benzaldehydes under conditions of microwave irradiation has been developed.
This method has many merits including high yields, short reaction times, ease of work-
1
up, and simple operation. All of the compounds have been characterized by H NMR, 13C
NMR, IR spectra and elemental analysis. In addition, the preliminary biological activity
tests showed that some of the title compounds remarkably enhanced the root elongation of
rape seedings; moreover, some compounds possessed antibacterial activity against Bacillus
subtilis.
Supplemental materials are available for this article. Go to the publisher’s online edition of
Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental
file.
Keywords Antibacterial activity; biological activity; hydrazone; triazole
INTRODUCTION
In recent years, a number of hydrazone derivatives have been claimed to possess a
wide range of biological activities, such as antituberculosis,1 antibacterial,2,3 analgesic/anti-
inflammatory,4 and antimicrobial activities.5 In addition, high-speed synthesis with mi-
crowaves has attracted a considerable amount of attention. The main benefits of performing
reactions under microwave irradiation conditions are the significant rate enhancements
and higher product yields. In view of this, and as a part of our previous work, a series
of novel [3-phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio]acetyl hydrazone derivatives
has been synthesized by the condensation reaction of [3-phenoxymethyl-4-phenyl-1,2,4-
triazole-5-yl-thio]acetyl hydrazine with various substituted benzaldehydes under conditions
of microwave irradiation.
Received 27 July 2009; accepted 2 November 2009.
This work was supported by the NSFC (No. 20671077) and the Natural Science Foundation of Gansu
(2008-1-164), which are gratefully acknowledged.
Address correspondence to You-Ming Zhang, College of Chemistry and Chemical Engineering, Key Lab-
oratory of Polymer Materials of Gansu Province, Northwest Normal University, Lanzhou, Gansu 730070, P. R.
China. E-mail: zhangnwnu@126.com
2030

MICROWAVE-INDUCED SYNTHESIS OF HYDRAZONE DERIVATIVES
2031
O
N
N
N
N
O
EtO CCH2Cl
O
N
S CH2COOEt
N
SH
CH CCH ,
K2CO3, reflux , 8h
3
3
O
2
1
O
N
N
R
O
NH2NH2 H2O, 85%, EtOH
reflux ,10h
O
HC
N
S CH2CNHNH2
MW, 6min
3
N
N
O
O
N
S CH2CNHN=C
R
4a-4h
o
g=
R:a-h: a=4-NO ; b=2-OH; c=4-OCH ; d=4-N(CH ) ; e=-H;
f=4-CHO;
2
3
3 2
o
h=
Br
Scheme 1
In this article, we have developed a facile and convenient method for the synthesis of
compounds 4a–4h under conditions of microwave irradiation (Scheme 1). The reaction here
has the following advantages: mild conditions, simple operation, short reaction times, and
high yield. In addition, the preliminary biological activity tests showed that the compounds
remarkably enhanced the root elongation of rape seedings.
RESULTS AND DISCUSSION
IR and NMR Investigation
The IR (KBr) spectra of all compounds exhibit intense sharp bands at 3185–
3244 cm−1, which are attributed to the stretching mode of the N H group. The absorption
bands that appeared at 1576–1602 cm−1 are assigned to the stretching vibration of the C N
group. Also it is worth mentioning that the spectra of all compounds exhibit a strong band at
1703–1663 cm−1, which can be assigned to the stretching mode for the C O group. In the
1H NMR spectra, an example of the compound 4a revealed signals at δ 4.54 and 4.13 ppm,
which were attributed to the protons of SCH2C O, compared with the foregoing spectral
data, which only appeared between δ 1.5 ppm and δ 2.5 ppm, owing to the CH2 group that
was connected with S atom and the electron-attracting C O group, which resulted in its
appearance at a lower frequency field. In addition, because the triazole ring system acted as
a better electron-withdrawing group than the C O group, δ 4.54 was assigned as linking
to the triazole ring, and δ 4.13 as connecting with the C O group. The signals at δ 12.07,
11.96 ppm and δ 8.31, 8.28 ppm were attributed to the protons of N H and N CH groups,
respectively. From the 13C NMR spectra, it could be found that in the CONH group exist
cis-trans conformers, and the N CH group could give rise to the formation of Z/E iso-
mers, which shows that the number of carbon absorption peaks were obviously increased.
As in the title compounds 4a–4h, the peaks resonated at about δ 33.71–34.74 ppm and
δ 59.63–59.88 ppm belonging to S C and O C groups, respectively; furthermore,

2032
T.-B. WEI ET AL.
the signals at around δ 140–150 ppm and δ 160–170 ppm correspond to N C- and C O
groups, respectively.
Solvent Effects on the 1H NMR Spectra
1
The effects of varying the solvent for H NMR spectra of compounds 4a–4h were
studied in organic solvents of various polarities: CDCl3, CD3CN, and DMSO. It was
observed that the 1H NMR spectra of a series of hydrazones derivatives were considerably
influenced by changing the solvent. Moreover, Z/E geometrical isomers and cis/trans amide
1
conformers have been found for hydrazone derivatives by H NMR investigation. For
example, in the 1H NMR spectra of the title compounds, all the SCH2C O, CONH, and
N CH groups of proton peaks appeared as doublet in polar DMSO-d6 or CD3CN. However,
they appeared as singlet in less polar CDCl3. According to the literature,6 in the highly polar
DMSO-d6 or CD3CN, the N CH protons mainly exist in the E form, and proton peaks
were assigned for cis conformer in the high field, and for trans at low field, but CONH
and SCH2C O of proton peaks were assigned to trans conformer at the high field, and for
cis in the low field, respectively. The percentage of conformers in DMSO-d6, CD3CN, and
CDCl3 are summarized in Table I according to the peak area.
Biological Activity
All the synthesized compounds were investigated for plant growth regulation activ-
ity. Method of plate culture was adopted, and the compound solutions were prepared in
concentrations of 100, 10, 1, 0.1, 0.01 and 0.001 ppm, whereafter, rape seeds were cultured
in a 10 cm Petri dish with 10 mL of different solution and a circular fiter paper. (See the
Supplemental Materials and Table S1, available online.)
EXPERIMENTAL
Melting points were recorded using a digital model X-4 apparatus and are uncorrected.
The reactions were carried out with a domestic microwave oven under atmospheric pressure.
IR spectra were recorded on a digital FTS-3000 infrared spectrometer (KBr pellet). 1H NMR
and 13C NMR spectra were determined as CDCl3 or DMSO-d6 solutions using a Varian
Mercury Plus-400 MHz spectrometer. Elemental analyses were determined using PE-2400
C H N elemental analyzer. All commercially available products were used without further
purification. [3-Phenoxymethyl-4- phenyl-1H-1,2,4-triazole-5(4H)]-thione 1 was prepared
according to the procedures in the literature.7–9
Table I Conformer percentagea of compounds 4a–4h
Isomer
4a
4b
4c
4d
4e
4f
4g
4h
Z
E
cis
trans
31
69
58
42
50
50
50
50
35
65
66
34
46
54
57
43
50
50
50
50
30
70
69
31
50
50
51
49
50
50
50
50
−CH N group is used as cis/trans referenced datum; CONH group and SCH2C O are used as cis/trans
referenced datum.

MICROWAVE-INDUCED SYNTHESIS OF HYDRAZONE DERIVATIVES
2033
General Procedure for the Synthesis of Compounds 4a–4h
The general synthesis routes of these compounds was as follows (Scheme 1).
[3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio]ethyl Acetate 2
A mixture of the [3-phenoxymethyl-4-phenyl-1H-1,2,4-triazole-5(4H)]-thione (20
mmol) 1, ethyl chloroacetate (22 mmol), and anhydrous potassium carbonate (25 mmol)
in acetone (50 mL) was heated under reflux on an oil bath for 8 h. Then the mixture was
filtered off, and the filtrate was evaporated and recrystallized from EtOH-H2O. Yield 79%,
white solid, mp 90–91◦C. IR (KBr): ν = 689 (C S C), 1237 (C O C), 1752 (C O)
cm−1. 1H NMR (CDCl3): δH = 1.23–1.28 (m, 3H, CH3), 4.06 (s, 2H, SCH2), 4.08–4.22 (m,
2H, CH2), 5.04 (s, 2H, OCH2);13C NMR (CDCl3): δC 14.11, 36.12, 59.76, 62.42, 114.73,
125.46, 128.27, 129.05, 129.30, 129.54, 147.38, 155.93, 160.79, 168.69. Anal. Calcd. for
C19H19N3O3S: C, 61.77; H, 5.18; N, 11.37. Found: C, 61.79; H, 5.16; N, 11.38.
[3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio]acetyl Hydrazine 3
[3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio]ethyl acetate (20 mmol) 2 was
added to a solution of ethanol (30 mL) in 85% hydrazine hydrate (20 mmol). The solution
was heated under reflux on an oil bath for 10 h. The mixture was filtered off and recrystallized
from EtOH-DMF-H2O. Yield 88%, white flaky crystal, mp 123–124◦C. IR (KBr): ν = 693
(C S C), 1232 (C O C), 1665 (C O), 3054 (Ar-H), 3262, 3333 (NHNH2) cm−1. 1H
NMR (DMSO-d6): δH = 3.90 (s, 2H, NH2), 4.30 (s, 2H, SCH2), 5.08 (s, 2H, OCH2),
6.85–7.57 (m, 10H, Ar-H), 9.36 (s, 1H, NH);13C NMR (DMSO-d6): δC = 34.05, 59.63,
114.72, 121.39, 126.93, 129.40, 129.71, 130.05, 132.53, 151.62, 157.26, 165.91. Anal.
Calcd. for C17H17N5O2S: C, 57.45; H, 4.82; N, 19.70. Found: C, 57.43; H, 4.81; N, 19.73.
[3-Phenoxymethyl-4-phenyl-1,2,4-triazol-5-yl-thio]acetyl Hydrazone
Derivatives 4a–4h
[3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio]acetyl hydrazine (2 mmol) 3,
the substituted benzaldehydes (2 mmol) or dialdehydes (1 mmol), and DMF (6 mL) were
placed in a dried round-bottomed flask, and the reaction mixture was subjected to mi-
crowave irradiation (230 W) for 1 min periods up to a total of 5 min irradiation (400 W)
again. The mixture was cooled to room temperature and then recrystallized from EtOH-
DMF. The structures of these compounds have been elucidated by spectral (IR, 1H NMR,
13C NMR) and elemental analysis data.
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-4-nitro-
benzylidenehy-drazine (4a). Yield 97%, light yellow solid, mp 200–202◦C. IR
(KBr): ν = 1573 (C N), 1524 (C N-N), 3058 (Ar-H), 1688 (C O), 1174 (C-O-C),
1
691 (C S C), 1344 (NO2), 3185 (N H) cm−1. H NMR (DMSO-d6): δH = 12.07 (s,
1H, NH), 11.96 (s, 1H, NH), 8.28 (s, 1H, N CH), 8.31 (s, 1H, N CH), 4.13 (s, 2H,
SCH2C O), 4.54 (s, 2H, SCH2C O), 5.08 (s, 2H, OCH2), 6.85–8.12 (m, 14H, Ar-H);13C
NMR (DMSO-d6): δC = 34.65, 59.72, 114.79, 121.45, 124.06, 127.01, 127.83, 128.07,
129.45, 130.10, 132.54, 140.21, 140.41, 141.51, 144.60, 147.78, 147.90, 151.38, 151.57,
151.69, 157.33, 163.79, 168.81. Anal. Calcd. for C24H20N6O4S: C, 59.01; H, 4.13; N,
17.20. Found:C, 59.03; H, 4.11; N, 17.18.

2034
T.-B. WEI ET AL.
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-2-hy-
droxybenzylidene-hydrazine (4b). Yield 89%, white solid, mp 224–226◦C. IR (KBr):
ν = 1619 (C N), 1580 (C N-N), 3059 (Ar-H), 1682 (C O), 1231 (C O C), 691
1
(C S C), 3177 (N H) cm−1. H NMR (CDCl3): δH 11.74 (s, 1H, NH), 11.04 (s, 1H,
OH), 8.28 (s, 1H, N CH), 3.92 (s, 2H, SCH2C O), 5.07 (s, 2H, OCH2), 6.84–7.63 (m,
13H, Ar-H); 13C NMR (CDCl3): δC = 33.96, 59.65, 114.75, 117.12, 117.35, 119.19,
122.01, 126.69, 129.60, 130.09, 130.77, 130.93, 131.78, 131.88, 150.71, 152.39, 154.25,
157.26, 158.59, 164.17. Anal. Calcd. for C24H21N5O3S: C, 62.73; H, 4.61; N, 15.24.
Found: C, 62.70; H, 4.64; N 15.27.
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-4-meth-
oxybenzyliden-ehydrazine (4c). Yield 92%, white solid, mp 210–212◦C. IR (KBr):
ν = 1600 (C N), 1502 (C N-N), 3072 (Ar-H), 1672 (C O), 1190 (C O C), 689
1
(C S C), 3188 (N-H) cm−1. H NMR (DMSO-d6): δH = 11.63 (s, 1H, NH), 11.56 (s,
1H, NH), 8.13 (s, 1H, N CH), 7.95 (s, 1H, N CH), 4.07 (s, 2H, SCH2C O), 4.48 (s,
2H, SCH2C O), 5.07 (s, 2H, OCH2), 6.85–7.66 (m, 14H, Ar-H); 3.80 (s, 3H, OCH3);
13C NMR (DMSO-d6): δC = 33.71, 53.43, 59.63, 112.79, 115.45, 121.64, 121.75, 125.01,
127.23, 128.63, 129.46, 129.68, 130.47, 130.62, 132.44, 132.61, 133.73, 138.81, 141.93,
147.73, 148.14, 157.33, 162.72, 168.01. Anal. Calcd. for C25H23N5O3S: C, 63.41; H, 4.90;
N, 14.79. Found: C, 63.43; H, 4.88; N, 14.77.
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-4-N,N-
dimethylbenzyl-idenehydrazine (4d). Yield 92%, gray solid, mp 188–190◦C. IR
(KBr): ν = 1602 (C N), 1524 (C N N), 3020 (Ar-H), 1669 (C O), 1184 (C O C),
691 (C S C), 3184 (N H) cm−1 1H NMR (CD3CN): δH = 10.84 (s, 1H, NH), 9.89 (s,
1H, NH), 8.32 (s, 1H, N CH), 8.52 (s, 1H, N CH), 4.46 (s, 2H, SCH2C O), 4.95 (s, 2H,
SCH2C O), 5.57 (s, 2H, OCH2), 7.29–8.11 (m, 14H, Ar-H), 2.51 (s, 3H, CH3), 2.49 (s,
3H, CH3). Anal. Calcd. for C26H26N6O2S: C, 64.18; H, 5.39; N, 17.27. Found: C, 64.20;
H, 5.41; N, 17.24.
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-benzyl-
idenehydrazine (4e). Yield 93%, white solid, mp 182–183◦C. IR (KBr): ν = 1594
(C N), 1492 (C N N), 3055 (Ar-H), 1687 (C O), 1215 (C O C), 689 (C S C),
1
3244 (N H) cm−1. H NMR (CDCl3): δH = 11.55 (s, 1H, NH), 8.14 (s, 1H, N CH),
3.93 (s, 2H, SCH2C O), 5.07 (s, 2H, OCH2), 6.86∼7.82 (m, 14H, Ar-H); 13C NMR
(CDCl3): δC = 34.29, 59.88, 115.05, 121.93, 122.25, 126.98, 127.27, 127.66, 128.08,
128.82, 129.75, 129.85, 130.33, 130.43, 130.73, 132.22, 133.74, 148.98, 152.62, 154.56,
157.57, 165.15. Anal. Calcd. for C24H21N5O2S: C, 64.99; H, 4.77; N, 15.79. Found: C,
64.95; H, 4.80; N, 15.82.
4-Bis{2-[(3-phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-
benzylidenehydrazine} (4f). Yield: 96%, yellow power solid, mp 253–255◦C, IR
(KBr): ν = 1594 (C N), 1494 (C N N), 3059 (Ar-H), 1663 (C O), 1213 (C O C),
689 (C S C), 3179 (N H) cm−1. 1H NMR (DMSO-d6): δH = 11.85 (s, 1H, NH), 11.76
(s, 1H, NH), 8.21 (s, 1H, N CH), 8.03 (s, 1H, N CH), 4.11 (s, 2H, SCH2C O), 4.52 (s,
2H, SCH2C O), 5.08 (s, 2H, OCH2), 6.85–7.77 (m, 14H, Ar-H). 13C NMR (DMSO-d6):
δC = 34.74, 59.72, 114.79, 121.44, 126.99, 127.02, 127.27, 127.54, 129.45, 129.77,
130.10, 132.57, 132.67, 135.24, 135.39, 143.14, 146.34, 151.76, 157.33, 163.36, 168.48.
Anal. Calcd. for C42H36N10O4S2: C, 62.36; H, 4.49; N, 17.32. Found: C, 62.39; H, 4.46;
N, 17.29.

MICROWAVE-INDUCED SYNTHESIS OF HYDRAZONE DERIVATIVES
2035
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-2-furan-
methylenehyd-razine (4g). Yield: 94%, coffee solid, mp 169–170◦C. IR (KBr):
ν = 1593 (C N), 1496 (C N N), 3062 (Ar-H), 1699 (C O), 1210 (C O C), 691
(C S C), 3219 (N H) cm−1. 1H NMR (CD3CN): δH = 11.15 (s, 1H, NH), 10.24 (s, 1H,
NH), 8.34 (s, 1H, N CH), 8.56 (s, 1H, N CH), 4.49 (s, 2H, SCH2C O), 4.93 (s, 2H,
SCH2C O), 5.57 (s, 2H, OCH2), 7.09–8.11 (m, 10H, Ar-H and 2H, furan). Anal. Calcd.
for C22H19N5O3S: C, 60.96; H, 4.42; N, 16.16. Found C, 60.93; H, 4.45; N, 16.18.
2-[(3-Phenoxymethyl-4-phenyl-1,2,4-triazole-5-yl-thio)-acetyl]-5-(4-bro-
mophenyl)-2-furanmethylenehydrazine (4h). Yield: 95%, yellow solid, mp
190–191◦C. IR (KBr): ν = 1593 (C N), 1495 (C N N), 3057 (Ar-H), 1679 (C O),
1
1187 (C O C), 692 (C S C), 3200 (N H) cm−1. H NMR (CDCl3): δH = 11.66 (s,
1H, NH), 8.11 (s, 1H, N CH), 3.93 (s, 2H, SCH2C O), 5.07 (s, 2H, OCH2), 6.69–7.78
(m, 14H, Ar-H and d, 2H, furan); 13C NMR (CDCl3): δC = 34.08, 59.73, 107.83, 114.75,
115.39, 121.67, 122.12, 125.66, 126.70, 127.01, 128.64, 129.58, 129.75, 130.04, 130.69,
131.83, 131.92, 134.84, 138.19, 148.75, 152.04, 154.62, 157.42, 164.74, 169.17. Anal.
Calcd. for C28H22N5O3SBr: C, 57.15; H, 3.77; N, 11.90. Found C, 57.13; H, 3.79; N,
11.92.
REFERENCES
1. B. K. Kaymakcıoglu and S. Rollas, Farmaco., 57, 595 (2002).
2. Q. Chen, D. Q. Long, J. Cheng, J. Li, Z. M. Liu, and G. F. Yang, Chem. J. Chin. Univ., 27, 454
(2006) (in Chinese).
3. T. B. Wei, M. L. Li, Q. Lin, H. Liu, and Y. M. Zhang, Chin. J. Org. Chem., 26, 477 (2006) (in
Chinese).
4. S. G. Umut, G. K. Nesrin, G. Ozgur, K. Yavuz, K. Ekrem, I. Samil, A. Goknur, and O. Meral,
Bioorg. Med. Chem., 15, 5738 (2007).
5. K. A. Metwally, L. M. Abdel-Aziz, El-S. M. Lashine, M. I. Husseiny, and R. H. Badawy, Bioorg.
Med. Chem., 14, 8675 (2006).
6. P. P. Domianop, Tetrahedron, 42(13), 3649 (1986).
7. T. B. Wei, J. Tang, Q. Lin, H. Liu, and Y. M. Zhang, Chem. J. Chin. Univ., 28(6), 1080 (2007) (in
Chinese).
8. T. B. Wei, R. Xu, J. Tang, and Y. M. Zhang, Chin. J. Org. Chem., 28(11), 1959 (2008) (in Chinese).
9. T. B. Wei, M. L. Li, Q. Li, H. Liu, and Y. M. Zhang, Phosphorus, Sulfur, and Silicon, 181, 1583
(2006).