Microwave-assisted synthesis and in vitro antibacterial activity of novel steroidal 1,2,4-triazole Schiff base derivatives

Article abstract of DOI:10.3184/174751914X13969706967486

A series of novel Schiff bases containing both a 1,2,4-triazole and deoxycholic acid skeleton have been synthesised in excellent yields and in high purity by means of microwave irradiation. The structures of the target compounds were characterised by MS, IR and NMR as well as elemental analysis. All the products were evaluated for their in vitro antibacterial activities against Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram negative bacteria (Pseudomonas seruginosa and Escherichia coli). Four of the compounds displayed varying levels of antibacterial activity against P. aeruginosa and S. aureus, but none of the compounds showed any activity against E. coli and B. subtilis.

Full text of DOI:10.3184/174751914X13969706967486

300 RESEARCH PAPER
VOL. 38 MAY, 300–303
JOURNAL OF CHEMICAL RESEARCH 2014
Microwave-assisted synthesis and in vitro antibacterial activity of novel
steroidal 1,2,4-triazole Schiff base derivatives
Xiaohong Wang Xingli Liu Yujia Jiang and Zhigang Zhao*
College of Chemistry and Environmental Protection Engineering, Southwest University for Nationalities, Chengdu 610041, P.R. China
A series of novel Schiff bases containing both a 1,2,4-triazole and deoxycholic acid skeleton have been synthesised in excellent
yields and in high purity by means of microwave irradiation. The structures of the target compounds were characterised by MS,
IR and NMR as well as elemental analysis. All the products were evaluated for their in vitro antibacterial activities against Gram
positive (Staphylococcus aureus and Bacillus subtilis) and Gram negative bacteria (Pseudomonas seruginosa and Escherichia
coli). Four of the compounds displayed varying levels of antibacterial activity against P. aeruginosa and S. aureus, but none of
the compounds showed any activity against E. coli and B. subtilis.
Keywords: 1,2,4-triazole, Schiff base, deoxycholic acid, microwave irradiation, antibacterial activity
1,2,4-Triazoles have a wide range of biological activities
including antibacterial activity.1 In previous work bile acids
such as deoxycholic acid have been used as conjugates with
triazoles and have been shown to have anti-bacterial activity.2
Schiff bases derived from triazoles have also been shown
to have anti-bacterial activity.3,4 Moreover, in recent years,
microwave irradiation has gained popularity as powerful tool
in green synthetic chemistry.5 This method of synthesis is not
only green, economic and easy to handle, but it also gives a
significant improvement in product yield, selectivity and
reaction time.6,7
In this work, three components, deoxycholic acid, a
1,2,4-triazole and a Schiff base have been combined. The anti-
bacterial activity has been evaluated against Pseudomonas
seruginosa, Escherichia coli, Staphylococcus aureus and
Bacillus subtilis. The value of microwave irradiation has been
demonstrated in the preparation of these compounds. The
synthetic route is shown in Scheme 1.
standards. The MIC was evaluated by double dilution method
using standard inocula of 105 CFU mL−1. Serial dilutions of the
test compounds, previously dissolved in DMSO were prepared
to give concentrations of 256, 128, 64, 32, 16, 8, 4, 2, 1, 0.5 and
0.25 μg mL−1. Each tube contained 1 mL bacterial fluid of 0.5
McFarland standards. The minimum inhibitory concentration
(MIC) was determined visually after incubation for 16 h, at
37°C. The lowest concentration, which showed no visible
growth, was taken as an end point for minimum MIC.
A standard inoculum of 105 CFU mL−1 was introduced onto
the surface of sterile agar plates. The filter papers measuring
6 mm in diameter previously soaked in a required concentration
(640, 320, 160, 80, 40, 20, 10 and 5 μg mL−1) of the test
compounds were placed in nutrient agar medium. Solvent and
growth controls were kept. The plates were incubated for 16 h
at 37 °C. The inhibition zones were measured and compared
with the controls, which helped to provide the IC50 values. The
results of MIC and IC50 are presented in Table 1.
As shown in Table 1, compounds 8b, 8d, 8f and 8h exhibited
moderate to poor antibacterial activity against P. aeruginosa
and S. aureus. They exhibited better antibacterial activity
against P. aeruginosa than S. aureus. None of the compounds
showed any activity against E. coli and B. subtilis. The
relationship between the structures and biological activity
indicated that monosubstituted halogen compounds showed
greater antibacterial activity, whereas disubstituted halogen
compounds had weaker antibacterial activity. For example, the
antibacterial activity of the compound 8b was better than that
of the compound 8d. Otherwise, compounds with an electron-
withdrawing group generally showed stronger activity than
Results and discussion
The structures of all the compounds 7 and 8a–j were confirmed
by IR, mass spectroscopy, NMR and elemental analysis.
Their mass spectra showed the expected molecular ion peaks
in high intensity. The IR spectra of compound 7 exhibited a
characteristic strong absorption at 3684–3149 cm–1 due to N–H
stretching vibration, which was absent in the IR spectra of 8a–
j. The appearance of a medium to strong absorption peak at
1615–1602 cm–1 is due to the stretching vibration of C=N bond
formation in the synthetic products. The carbonyl absorption
band observed at 1734–1732 cm–1 and C=S stretching band was
seen in the range of 1297–1280 cm–1. In the H NMR spectra,
1
compound 7 showed a singlet peak at δ 6.17 ppm attributed
to the NH2 group which was not present in the spectra of
compounds 8a–j. The singlet peaks at δ 9.10–8.76 ppm were
assigned to the N=CH proton. The protons of ArH appeared
at δ 8.69–6.91 ppm. In the 13C NMR spectra, the triazole C3
and C5 of compounds 7 and 8a–j were observed at δ 151.16–
150.31 ppm and δ 174.26–174.21 ppm respectively. The carbons
of C=N were found in the region at δ 146.59–146.38 ppm.
Table 1 Bacterial inhibition results for compounds 8a–j and two positive
controls (ciprofloxacin and amoxicillin)
E. coli
B. subtilis P. aeruginosa S. aureus
Compd
MIC IC50 MIC IC50 MIC IC50 MIC IC50
Ciprofloxacin 0.25 0.18 0.125 0.1
0.5
4
–
0.41 3.12 1.82
Amoxicillin
16
–
–
–
–
–
–
–
–
–
–
7.3
2
–
–
–
–
–
–
–
–
–
–
1
–
–
–
–
–
–
–
–
–
–
2.5
16
6.4
8a
8b
8c
8d
8e
8f
8g
8h
8i
–
–
–
–
–
–
–
–
–
–
–
32 17.34 32 18.72
–
64 32.45
–
64 32.26 64 32.46
–
64 33.45 128 63.43
–
–
–
–
–
–
–
–
In vitro antibacterial activity
The in vitro antibacterial activities of compounds 8a–j were
examined using cultures of the gram-negative bacteria (P.
seruginosa and E. coli) and gram-positive bacteria (S. aureus
and B. subtilis). Amoxicillin and ciprofloxacin were used as the
–
–
–
–
–
–
–
–
8j
–
* Correspondent. E-mail: zzg63129@163.com
– Inactive to inhibit bacteria.
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JOURNAL OF CHEMICAL RESEARCH 2014 301
i
ii
F
COOH
F
COOC2H5
CONHNH2
F
2
1
N
NH
iii
iv
CONHNHCSS-K+
F
S
F
N
4
3
NH2
COOH
COOCH3
v
vi
OH
OH
5
OH
OH
COOCH3
COOCH3
OH
OH
viii
vii
O
O
F
O
O
N
N
Cl
6
N
S
7
NH2
COOCH3
OH
8a R = C6H5
8c R= 3-FC6H4
8b R = 4-FC6H4
8d R= 2,4-F2C6H3
8f R = 2-ClC6H4
8h R = 2-BrC6H4
8j R= 4-NO2C6H4
O
O
N
F
N
N
8e R= 4-ClC6H4
8g R = 4-BrC6H4
S
N
8a-j
HC
R
8i R= 4-CH3OC6H4
Scheme 1 Reagents and conditions: (i) SOCl2, C2H5OH, MWI (microwave irradiation); (ii) NH2NH2·H2O, MWI; (iii) CS2, KOH, C2H5OH; (iv) NH2NH2·H2O, MWI;
(v) CH3COCl, CH3OH; (vi) pyridine, ClCH2COCl, CHCl3, MWI; (vii) 4, K2CO3, DMF, MWI; (viii) RCHO, AcOH, MWI.
those with an electron-donating group. The potency order was
F (fluorine)>Cl (chlorine)>Br (bromine). Further antibacterial
activity studies are in progress.
In summary, we have developed a simple method for the
synthesis of novel Schiff bases containing both 1,2,4-triazole
and deoxycholic acid skeleton under microwave irradiation
giving excellent yields of the products in shorter reaction time.
All the synthesised compounds have been investigated for
their in vitro antibacterial activities. From the activity studies,
compounds 8b, 8d, 8f and 8h were shown to possess some
antibacterial activity against P. aeruginosa and S. aureus. This
study may provide valuable information for further designing
and developing more potent antibacterial agents for the
biological and pharmacological use.
Comparison of microwave irradiation and conventional heating
As shown in Table 2, microwave irradiation significantly
reduced the reaction time from 420–780 min to 3–7 min and
the yields increased from 62–70% to 86–94%. We can conclude
that microwave irradiation is a simple, efficient and rapid
synthetic method.
Table 2 Comparison of microwave irradiation with conventional heating
for the efficiency of synthesis of compounds 8a–j
Experimental
Conventional
method
t/min Yield/%
Microwave
method
t/min Yield/%
Melting points were determined on a micro-melting point apparatus
and the thermometer was uncorrected. IR spectra were obtained
RCHO
(R)
Compd
tC/tMW
1
on 1700 PerkinElmer FTIR using KBr disks. H NMR and 13C NMR
8a
8b
8c
8d
8e
8f
8g
8h
8i
C6H5
480
600
660
450
660
720
540
600
69
66
64
70
64
67
63
65
62
69
3.5
5.0
4.5
4.0
6.0
7.0
5.0
4.5
7.0
3.0
93
91
89
94
90
93
87
90
86
92
137
120
147
113
110
103
108
133
111
140
spectra were recorded on a Bruker 400 MHz spectrometer using
DMSO-d6 as solvent and TMS as internal standard. Mass spectra were
determined on FinniganLCQDECA instrument. Elemental analysis
(C, H, and N) was performed on a VarioMICRO auto analyser. All
reactions were performed in a commercial microwave reaction
(XH-100A, 100–1000 W, Beijing XiangHu Science and Technology
Development Co. Ltd, Beijing, P.R. China). The disinfection of
apparatus and reagents used in vitro antimicrobial activity test was
conducted in a portable stainless steel pressure steam steriliser
(YX280A, Shanghai Sanshen Medical Instrument Co., Ltd, Shanghai,
P.R. China). A sterile operation was carried out on a super clean bench
4-F–C6H4
3-F–C6H4
2,4-F2–C6H3
4-Cl–C6H4
2-Cl–C6H4
4-Br–C6H4
2-Br–C6H4
4-OCH3–C6H4 780
4-NO2–C6H4 420
8j
tC, Conventional method time; tMW, microwave method time.
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302 JOURNAL OF CHEMICAL RESEARCH 2014
(DL-CJ-1N, Donglian Electronic & Technology Development Co. Ltd,
Beijing, P.R. China). Bacterial culture was operated in a biologically
constant temperature incubator (ECA-9272, Beijing ECOA Science
& Development Co., Ltd, Beijing, P.R. China). All the chemicals and
solvents were dried and purified before use. Intermediates 3 and 4 were
prepared following the literature methods.8
3β-H), 4.24 (s, 1H, 12β-H), 4.01 (s, 2H, –OCOCH2N), 3.78 (s, 1H, 12α-
OH), 3.57 (s, 3H, –CO2CH3), 0.91 (d, J=6.4 Hz, 3H, 21-CH3), 0.83 (s,
3H, 19-CH3), 0.58 (s, 3H, 18-CH3); 13C NMR (DMSO-d6, 100 MHz)
δ 174.22, 167.78, 167.55, 164.63, 164.29, 150.79, 146.49, 132.48,
132.36, 130.61, 130.53, 128.56, 128.54, 123.29, 123.26, 117.06, 117.00,
116.57, 116.49, 75.57, 71.38, 51.62, 47.82, 46.53, 46.40, 41.55, 35.94,
35.88, 35.34, 34.75, 34.09, 33.23, 31.94, 31.09, 30.85, 28.95, 27.56,
26.99, 26.36, 26.14, 23.82, 23.16, 17.31, 12.79; ESI-MS m/z (%): 1547
([2M+Na]+, 100). Anal. calcd for C42H52F2N4O5S: C, 66.12; H, 6.87; N,
7.34; found: C, 66.01; H, 6.85; N, 7.31%.
Synthesis of the intermediate methyl 3α-(2-(4-amino-3-(4-
fluorophenyl)-5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)-acetoxy)-12α-
hydroxy-cholanate 7
Methyl 3α-(2-(4-amino-3-(4-fluorophenyl)-5-thioxo-4,5-dihydro-
1,2,4-triazol-1-yl)-acetoxy)-12α-hydroxy-cholanate 7 was synthesised
using a literature method.2 The solid product obtained was purified
by flash chromatography (elution with ethyl acetate:petroleum
[α]20
Methyl 3α-(2-(4-(3-fluorobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
cholanate (8c): White solid; yield 89%; m.p. 81–82 °C;
–151.5
D
(c 0.15, CH2Cl2); IR (KBr)(cm-1): 3442, 2940, 2867, 1733, 1608, 1582,
ether=4:1–8:1). White solid; yield 96%; m.p. 121–122 °C;
D –45.8
1
1476, 1448, 1294, 1159, 1092, 842; H NMR (DMSO-d6, 400 MHz)
(c 0.17, CH2Cl2); IR (KBr)(cm–1): 3324, 3195, 2938, 2867, 1732, 1606,
δ 8.90 (s, 1H, =CH), 7.94–7.90 (m, 2H, ArH), 7.80–7.76 (m, 2H,
ArH), 7.68–7.63 (m, 1H, ArH), 7.54 (t, J=7.6 Hz, 1H, ArH), 7.38 (t,
J=8.8 Hz, 2H, ArH), 4.58 (s, 1H, 3β-H), 4.22 (s, 1H, 12β-H), 4.02 (s,
2H, –OCOCH2N), 3.78 (s, 1H, 12α-OH), 3.57 (s, 3H, –CO2CH3), 0.91
(d, J=6.4 Hz, 3H, 21-CH3), 0.84 (s, 3H, 19-CH3), 0.58 (s, 3H, 18-CH3);
13C NMR (DMSO-d6, 100 MHz) δ: 174.26, 167.84, 167.13, 164.67,
163.96, 150.91, 146.48, 134.13, 134.06, 132.10, 132.01, 130.72, 130.63,
126.13, 123.15, 123.12, 120.81, 120.60, 116.52, 116.30, 115.56, 115.34,
75.63, 71.41, 51.62, 47.75, 46.48, 46.39, 41.54, 35.96, 35.87, 35.35, 34.74,
34.08, 33.19, 31.93, 31.07, 30.81, 28.88, 27.57, 26.97, 26.34, 26.18, 23.82,
23.12, 17.26, 12.76; ESI-MS m/z (%): 763 ([M+1]+, 100). Anal. calcd for
C42H52F2N4O5S: C, 66.12; H, 6.87; N, 7.34; found: C, 66.23; H, 6.89; N,
7.37%.
1
1458, 1382, 1298, 1184, 1041, 982, 897, 843. H NMR (DMSO-d6,
400 MHz) δ 8.01–7.98 (m, 2H, ArH), 7.34 (t, J=8.0 Hz 2H, ArH),
6.17 (s, 2H, NH2), 4.63 (s, 1H, 3β-H), 4.21 (s, 1H, 12β-H), 4.03 (s, 2H,
–OCOCH2N), 3.75 (s, 1H, 12α-OH), 3.54 (s, 3H, –CO2CH3), 0.88 (d,
J=6.4 Hz, 3H, 21-CH3), 0.83 (s, 3H, 19-CH3), 0.56 (s, 3H, 18-CH3); 13
C
NMR (DMSO-d6, 100 MHz) δ 174.22, 168.33, 164.53, 153.27, 130.55,
130.47, 123.78, 123.75, 116.14, 115.92, 75.61, 71.44, 51.62, 47.82, 46.54,
46.42, 41.60, 35.93, 35.36, 34.82, 34.15, 33.79, 33.23, 32.06, 31.10, 30.87,
28.94, 27.57, 27.02, 26.43, 26.29, 23.88, 23.16, 17.29, 12.81; ESI-MS m/z
(%): 1335 ([2M+Na]+, 100). Anal. calcd for C35H49FN4O5S: C, 64.00; H,
7.52; N, 8.53; found: C, 64.13; H, 7.50; N, 8.50%.
Synthesis of compounds 8a–j; general procedure
Methyl 3α-(2-(4-(2,4-difluorobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
Conventional method: Compound 7 (0.164 g, 0.25 mmol), aldehyde
(0.26 mmol), and glacial acetic acid (10 mL) were placed in a round-
bottomed flask and the reaction mixture was heated to reflux for
420–780 min. When the reaction was complete (monitored by
TLC), the flask was cooled to room temperature and evaporated
to remove the glacial acetic acid. The solid residue was purified
by flash chromatography (elution with ethyl acetate:petroleum
ether=1:1–2:1) to give pure 8a–j (62–70%).
Microwave irradiation method: Compound 7 (0.164 g, 0.25 mmol),
aldehyde (0.26 mmol), and glacial acetic acid (5 mL) were mixed
thoroughly in a sealed vessel. The vessel was then placed in a
microwave oven and the mixture was irradiated at 300 W for 3–7 min.
The reaction was monitored by TLC until it was complete. The solvent
was removed and the solid residue was subject to flash chromatography
(elution with ethyl acetate:petroleum ether=1:1–2:1) for purification
to give pure 8a–j (86–94%). The physical and spectra data of
compounds 8a–j are as follows:
cholanate (8d): White solid; yield 94%; m.p. 77–79 °C;
D –175.6
(c 0.20, CH2Cl2); IR (KBr)(cm–1): 3450, 2940, 2867, 1734, 1615, 1583,
1476, 1437, 1280, 1159, 1092, 968, 843; 1H NMR (DMSO-d6, 400 MHz)
δ 8.98 (s, 1H, =CH), 8.17–8.11 (m, 1H, ArH), 7.93–7.90 (m, 2H, ArH),
7.58–7.52 (m, 1H, ArH), 7.40–7.32 (m, 3H, ArH), 4.58–4.54 (m, 1H,
3β-H), 4.23 (s, 1H, 12β-H), 4.02 (s, 2H, –OCOCH2N), 3.77 (s, 1H, 12α-
OH), 3.57 (s, 3H, –CO2CH3), 0.92 (d, J=6.4 Hz, 3H, 21-CH3), 0.83 (s,
3H, 19-CH3), 0.58 (s, 3H, 18-CH3); 13C NMR (DMSO-d6, 100 MHz) δ:
174.21, 167.80, 167.27, 164.74, 164.69, 164.61, 164.24, 164.11, 161.67,
161.54, 150.95, 146.38, 130.79, 130.71, 123.28, 123.25, 116.67, 116.60,
116.57, 116.46, 116.24, 113.99, 113.77, 105.96, 105.70, 105.45, 75.62,
71.40, 51.60, 47.78, 46.52, 46.40, 41.56, 36.02, 35.89, 35.35, 34.76,
34.09, 33.21, 31.94, 31.09, 30.81, 28.93, 27.56, 26.99, 26.35, 26.15, 23.82,
23.13, 17.29, 12.78; ESI-MS m/z (%): 803 ([M+Na]+, 100). Anal. calcd
for C42H51F3N4O5S: C, 64.60; H, 6.58; N, 7.30; found: C, 64.71; H, 6.55;
N, 7.32%.
Methyl 3α-(2-(4-(benzylideneamino)-3-(4-fluorophenyl)-5-thioxo-
4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-cholanate (8a):
[α]20
Methyl 3α-(2-(4-(4-chlorobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
White solid; yield 93%; m.p. 86–88 °C;
–101.3 (c 0.17, CH2Cl2);
D
IR (KBr)(cm–1): 3440, 2937, 2866, 1733, 1608, 1532, 1441, 1290,
1165, 1092, 840; 1H NMR (DMSO-d6, 400 MHz) δ 8.88 (s, 1H, =CH),
7.96–7.90 (m, 4H, ArH), 7.68 (t, J=7.2 Hz, 1H, ArH), 7.60 (t, J=7.4 Hz,
2H, ArH), 7.37 (t, J=8.8 Hz, 2H, ArH), 4.59 (s, 1H, 3β-H), 4.22 (s,
1H, 12β-H), 4.05 (s, 2H, –OCOCH2N), 3.78 (s, 1H, 12α-OH), 3.57 (s,
3H, –CO2CH3), 0.91 (d, J=6.0 Hz, 3H, 21-CH3), 0.84 (s, 3H, 19-CH3),
0.58 (s, 3H, 18-CH3); 13C NMR (DMSO-d6, 100 MHz) δ 174.23, 168.81,
167.83, 164.62, 150.80, 146.49, 133.86, 131.85, 130.63, 130.54, 129.81,
129.63, 123.29, 116.51, 116.29, 75.60, 71.39, 51.63, 47.79, 46.52, 46.41,
41.55, 35.90, 35.84, 35.36, 34.77, 34.11, 33.21, 31.96, 31.10, 30.84, 28.94,
27.57, 27.00, 26.36, 26.18, 23.85, 27.16, 17.30, 12.81; ESI-MS m/z (%):
745 ([M+1]+, 100). Anal. calcd for C42H53FN4O5S: C, 67.72; H, 7.17; N,
7.52; found: C, 67.84; H, 7.15; N, 7.54%.
cholanate (8e): White solid; yield 90%; m.p. 76–78 °C;
D –85.2
(c 0.13, CH2Cl2); IR (KBr)(cm–1): 3436, 2934, 2866, 1732, 1603, 1532,
1446, 1289, 1165, 1090, 835; 1H NMR (DMSO-d6, 400 MHz) δ: 8.89 (s,
1H, =CH), 7.97 (d, J=8.4 Hz, 2H, ArH), 7.73–7.89 (m, 2H, ArH), 7.69
(d, J=8.4 Hz, 2H, ArH), 7.36 (t, J=8.6 Hz, 2H, ArH), 4.56–4.53 (m, 1H,
3β-H), 4.24 (s, 1H, 12β-H), 4.01 (s, 2H, –OCOCH2N), 3.78 (s, 1H, 12α-
OH), 3.57 (s, 3H, –CO2CH3), 0.91 (d, J=6.4 Hz, 3H, 21-CH3), 0.83 (s,
3H, 19-CH3), 0.58 (s, 3H, 18-CH3); 13C NMR (DMSO-d6, 100 MHz) δ:
174.22, 167.74, 167.35, 164.65, 150.82, 146.50, 138.58, 131.26, 130.76,
130.65, 130.56, 130.04, 123.26, 123.23, 116.49, 116.27, 75.56, 71.37,
51.62, 47.85, 46.52, 46.40, 41.53, 36.09, 35.87, 35.32, 34.75, 32.14, 33.23,
31.93, 31.10, 30.86, 28.95, 27.55, 26.98, 26.36, 26.12, 23.82, 23.16,
17.32, 12.80; ESI-MS m/z (%): 801 ([M+Na]+, 100). Anal. calcd for
C42H52ClFN4O5S: C, 64.72; H, 6.72; N, 7.19; found: C, 64.60; H, 6.75;
N, 7.16%.
Methyl 3α-(2-(4-(4-fluorobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
cholanate (8b): White solid; yield 91%; m.p. 77–78 °C;
–48.1 (c
Methyl 3α-(2-(4-(2-chlorobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
D
0.20, CH2Cl2); IR (KBr)(cm–1): 3442, 2939, 2868, 1733, 1602, 1583,
1510, 1479, 1297, 1158, 1092, 840; 1H NMR (DMSO-d6, 400 MHz) δ:
8.88 (s, 1H, =CH), 8.05–8.02 (m, 2H, ArH), 7.93–7.90 (m, 2H, ArH),
7.45 (t, J=8.2 Hz, 2H, ArH), 7.36 (t, J=8.6 Hz, 2H, ArH), 4.57 (s, 1H,
[α]20
cholanate (8f): White solid; yield 93%; m.p. 85–86 °C;
–160.3
D
(c 0.13, CH2Cl2); IR (KBr)(cm–1): 3448, 2938, 2867, 1734, 1607, 1585,
1478, 1438, 1295, 1159, 1091, 841, 755; 1H NMR (DMSO-d6, 400 MHz)
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JOURNAL OF CHEMICAL RESEARCH 2014 303
δ 9.10 (s, 1H, =CH), 8.13 (d, J=7.2 Hz, 1H, ArH), 7.93–7.89 (m, 2H,
ArH), 7.67 (d, J=3.6 Hz, 2H, ArH), 7.58–7.54 (m, 1H, ArH), 7.40 (t,
J=8.8 Hz, 2H, ArH), 4.61–4.56 (m, 1H, 3β-H), 4.22 (s, 1H, 12β-H), 4.07
(s, 2H, –OCOCH2N), 3.77 (s, 1H, 12α-OH), 3.57 (s, 3H, –CO2CH3), 0.91
(d, J=6.4 Hz, 3H, 21-CH3), 0.84 (s, 3H, 19-CH3), 0.58 (s, 3H, 18-CH3);
13C NMR (DMSO-d6, 100 MHz) δ 174.23, 167.82, 164.71, 151.12,
146.44, 135.79, 135.06, 131.00, 130.92, 130.90, 129.38, 128.74, 128.65,
123.33, 123.30, 116.52, 116.30, 75.66, 71.40, 51.63, 47.76, 46.51, 46.41,
41.56, 35.90, 35.85, 35.36, 34.76, 34.11, 33.21, 31.97, 31.09, 30.84, 28.92,
27.57, 27.00, 26.37, 26.19, 23.85, 23.16, 17.30, 12.80; ESI-MS m/z (%):
1579 ([2M+Na]+, 100). Anal. calcd for C42H52ClFN4O5S: C, 64.72; H,
6.72; N, 7.19; found: C, 64.81; H, 6.69; N, 7.17%.
(d, J=9.2 Hz, 2H, ArH), 4.57 (s, 1H, 3β-H), 4.24 (s, 1H, 12β-H), 4.00 (s,
2H, –OCOCH2N), 3.86 (s, 3H, –OCH3), 3.78 (s, 1H, 12α-OH), 3.57 (s,
3H, –CO2CH3), 0.92 (d, J=6.4 Hz, 3H, 21-CH3), 0.83 (s, 3H, 19-CH3),
0.58 (s, 3H, 18-CH3); 13C NMR (DMSO-d6, 100 MHz) δ: 174.22, 168.59,
167.81, 164.56, 163.91, 150.65, 146.51, 131.74, 130.48, 130.39, 124.35,
123.39, 116.44, 116.22, 115.32, 75.59, 71.40, 56.04, 51.61, 47.80, 46.54,
46.41, 41.56, 35.90, 34.71, 35.36, 34.77, 34.10, 33.23, 31.94, 31.11, 30.84,
28.95, 27.57, 27.00, 26.37, 26.17, 23.83, 23.15, 17.29, 12.78; ESI-MS m/z
(%): 1571 ([2M+Na]+, 100). Anal. calcd for C43H55FN4O6S: C, 66.64; H,
7.15; N, 7.23; found: C, 66.52; H, 7.12; N, 7.25%.
Methyl 3α-(2-(4-(4-nitrobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
Methyl 3α-(2-(4-(4-bromobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
[α]2D0
cholanate (8j): Yellow solid; yield 92%; m.p. 101–102 °C;
–133.8 (c 0.16, CH2Cl2); IR (KBr)(cm–1): 3436, 2939, 2867, 1733, 1608,
1
cholanate (8g): White solid; yield 87%; m.p. 90–91 °C;
–189.2
1596, 1526, 1438, 1346, 1295, 1159, 1095, 845; H NMR (DMSO-d6,
D
(c 0.15, CH2Cl2); IR (KBr)(cm–1): 3441, 2938, 2867, 1733, 1608, 1589,
400 MHz) δ 9.05 (s, 1H, =CH), 8.45 (d, J=8.4 Hz, 2H, ArH), 8.22
(d, J=8.4 Hz, 2H, ArH), 7.95–7.90 (m, 2H, ArH), 7.37 (t, J=8.8 Hz,
2H, ArH), 4.59–4.51 (m, 1H, 3β-H), 4.26 (s, 1H, 12β-H), 4.04 (s, 2H,
–OCOCH2N), 3.79 (s, 1H, 12α-OH), 3.57 (s, 3H, –CO2CH3), 0.93 (d,
1
1475, 1438, 1295, 1159, 1097, 841; H NMR (DMSO-d6, 400 MHz)
δ 8.88 (s, 1H, =CH), 7.93–7.89 (m, 4H, ArH), 7.83 (d, J=8.0 Hz, 2H,
ArH), 7.36 (t, J=8.8 Hz, 2H, ArH), 4.58–4.53 (m, 1H, 3β-H), 4.24 (s,
1H, 12β-H), 4.02 (s, 2H, –OCOCH2N), 3.78 (s, 1H, 12α-OH), 3.57 (s,
3H, –CO2CH3), 0.93 (d, J=6.0 Hz, 3H, 21-CH3), 0.83 (s, 3H, 19-CH3),
0.58 (s, 3H, 18-CH3); 13C NMR (DMSO-d6, 100 MHz) δ 174.22, 167.71,
167.44, 164.66, 150.82, 146.48, 132.97, 131.35, 131.09, 130.64, 130.56,
127.70, 123.24, 116.47, 116.25, 75.56, 71.39, 51.62, 47.85, 46.52, 46.40,
41.54, 35.87, 35.88, 35.32, 34.75, 34.06, 33.23, 31.93, 31.09, 30.81, 28.95,
27.56, 26.97, 26.35, 26.11, 23.82, 23.15, 17.31, 12.79; ESI-MS m/z (%):
847 ([M+Na]+, 100). Anal. calcd for C42H52BrFN4O5S: C, 61.23; H,
6.36; N, 6.80; found: C, 61.10; H, 6.38; N, 6.78%.
J=6.4 Hz, 3H, 21-CH3), 0.82 (s, 3H, 19-CH3), 0.58 (s, 3H, 18-CH3); 13
C
NMR (DMSO-d6, 100 MHz) δ: 174.22, 167.65, 165.73, 164.75, 151.06,
150.31, 146.59, 137.57, 130.82, 130.75, 130.73, 124.91, 123.14, 123.11,
116.52, 116.31, 75.53, 71.38, 51.62, 47.90, 46.59, 46.40, 41.52, 36.38,
35.86, 35.32, 34.72, 34.06, 33.23, 31.94, 31.08, 30.81, 28.96, 27.53,
26.97, 26.36, 26.09, 23.79, 23.16, 17.32, 12.81; ESI-MS m/z (%): 812
([M+Na]+, 100). Anal. calcd for C42H52FN5O7S: C, 63.86; H, 6.63; N,
8.87; found: C, 63.75; H, 6.65; N, 8.89%.
Methyl 3α-(2-(4-(2-bromobenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
This work was supported by the Science and Technology
Department of Sichuan Province (No. 2012SZ0160) and the
Project of Postgraduate Degree Construction, Southwest
University for Nationalities (No. 2013XWD-S0703).
cholanate (8h): White solid; yield 90%; m.p. 82–83 °C;
–169.5
D
(c 0.18, CH2Cl2); IR (KBr)(cm–1): 3450, 2937, 2866, 1734, 1608, 1560,
1476, 1437, 1295, 1159, 1092, 841, 756; 1H NMR (DMSO-d6, 400 MHz)
δ 9.02 (s, 1H, =CH), 8.12–8.10 (m, 1H, ArH), 7.92–7.88 (m, 2H, ArH),
7.84–7.82 (m, 1H, ArH), 7.60–7.58 (m, 2H, ArH), 7.40 (t, J=8.8 Hz,
2H, ArH) 4.61–4.59 (m, 1H, 3β-H), 4.22 (s, 1H, 12β-H), 4.08 (s, 2H,
–OCOCH2N), 3.77 (s, 1H, 12α-OH), 3.57 (s, 3H, –CO2CH3), 0.93 (d,
Received 28 January 2014; accepted 13 March 2014
Paper 1402432 doi: 10.3184/174751914X13969706967486
Published online: 6 May 2014
J=6.4 Hz, 3H, 21-CH3), 0.83 (s, 3H, 19-CH3), 0.58 (s, 3H, 18-CH3); 13
C
NMR (DMSO-d6, 100 MHz) δ 174.22, 167.80, 164.75, 151.16, 146.41,
135.18, 134.17, 131.05, 130.96, 130.89, 129.12, 129.05, 126.05, 123.33,
123.30, 116.43, 116.31, 75.67, 71.40, 51.62, 47.76, 46.51, 46.41, 41.57,
35.90, 35.81, 35.36, 34.77, 34.11, 33.21, 31.99, 31.09, 30.84, 28.92, 27.57,
27.01, 26.37, 26.20, 23.85, 23.15, 17.29, 12.79; ESI-MS m/z (%): 823
([M+1]+, 100). Anal. calcd for C42H52BrFN4O5S: C, 61.23; H, 6.36; N,
6.80; found: C, 61.31; H, 6.33; N, 6.82%.
References
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Methyl 3α-(2-(4-(4-methoxybenzylideneamino)-3-(4-fluorophenyl)-
5-thioxo-4,5-dihydro-1,2,4-triazol-1-yl)acetoxy)-12α-hydroxy-
[α]20
cholanate (8i): White solid; yield 86%; m.p. 91–92 °C;
–140.7 (c
D
0.10, CH2Cl2); IR (KBr)(cm–1): 3442, 2937, 2867, 1734, 1602, 1568, 1513,
1438, 1296, 1169, 1093, 839; 1H NMR (DMSO-d6, 400 MHz) δ 8.76 (s,
1H, =CH), 7.93–7.90 (m, 4H, ArH), 7.36 (t, J=7.8 Hz, 2H, ArH), 7.15
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