Synthesis and structural characterisation of 2,4-bis(5-aryl-1,3,4-oxdiazol- 2-yl) pyridine derivatives

Article abstract of DOI:10.3184/030823410X12747104952034

A convenient synthesis of 2,4-bis (5-aryl-1,3,4-oxdiazol-2-yl) derivatives of pyridine by the POCl₃-mediated cyclodehydration of a variety of pyridine-2,4-dicarboxylic dihydrazides has been developed. The 20 novel intermediates and target molecules were characterised by IR, 1H NMR, MS and elemental analysis.

Full text of DOI:10.3184/030823410X12747104952034

JOURNAL OF CHEMICAL RESEARCH 2010
RESEARCH PAPER 307
JUNE, 307–309
Synthesis and structural characterisation of 2,4-bis(5-aryl-1,3,4-oxdiazol-
2-yl) pyridine derivatives
XiaoQing Wang, ZhiGang Zhao*, XingLi Liu and WeiJie Li
College of Chemistry and Environmental Protection Engineering, Southwest University for Nationalities, Chengdu 610041, P.R. China
A convenient synthesis of 2,4-bis (5-aryl-1,3,4-oxdiazol-2-yl) derivatives of pyridine by the POCl3-mediated cyclo-
dehydration of a variety of pyridine-2,4-dicarboxylic dihydrazides has been developed. The 20 novel intermediates
and target molecules were characterised by IR, 1H NMR, MS and elemental analysis.
Keywords: pyridine-2,4-dicarboxylic acid, pyridine-2,4-dicarboxylic dihydrazides, 2,4-bis(5-aryl-1,3,4-oxdiazol-2-yl)pyridine
1,3,4-Oxadiazoles are an important class of heterocyclic com-
pounds possessing a wide range of biological activities. The
interest in their synthesis stems from their anti-inflammatory,1
antimicrobial,2 antifungal,3 anticonvulsant,4 antihypertensive5
and anticancer,6 insecticide,7 enzyme inhibitory8 and kinase9
activities. Substituted 1,3,4-oxdiazole heterocycles are also
useful intermediates in organic synthesis11 and an important
scaffold in medicinal chemistry.12 Further, they have proved to
be useful in material science for their fluorescence and electro-
chromic properties.13,14 Compounds with a 1,3,4-oxdiazole
core have also been widely employed as electron transporting
and hole-blocking materials.15
The present investigation describes many bisheterocyclic
compounds endowed with potentially significant bioactivities.
In studies by Holla et al.16, some bis-1,2,4-triazole compounds
were found to be active against dozens of cancer cell lines. In
addition, bisoxadiazoles show good electronic transmission
performance and are widely used in organic electroluminesent
materials.17 Furthermore, it has been reported that many bio-
logical active natural and synthetic products have interesting
molecular symmetry.18 It is also observed that incorporation of
more active structures into the same molecule augments the
biological activities considerably.19
Prompted by these observations and in continuation of our
attempt to prepare new heterocyclic compounds with antici-
pated biological activity, which can be used in the pharmaceu-
tical field, we designed the synthesis of a series of novel
pyridine-2,4-dicarboxylic dihydrazides and 2,4-bis(5-aryl-
1,3,4-oxadiazol-2-yl)pyridines starting from a substituted
benzoic acid and pyridine-2,4-dicarboxylic acid. The synthesis
and characterisation of the newly synthesised compounds are
now presented. These compounds were synthesised according
to Scheme 1.
bishydrazides of the series showed similar absorption bands.
The H NMR spectra of 6a showed four sharp singlets at δ
1
10.62, 10.69, 10.79 and 11.08 corresponding to the four NH
protons. The pyridine protons resonated at δ 9.38, 8.53 and
8.10 integrating for three protons. Two multiplets in the region
δ 7.91–7.96 and δ 7.52–7.67 are attributed to the aromatic pro-
1
tons. The H NMR spectra of the other compounds exhibited
similar chemical shift ranges. The mass spectra and elemental
analyses of compounds 6a–j were in full agreement with their
structures.
The synthesis of target scaffolds 7a–i, (Scheme 1) was cata-
lysed by POCl3 as dehydrating agent and gave the products in
good yields (67–82%). The IR spectrum of compound 7a
showed absorption bands at 1539 and 1076 cm−1corresponding
to the C=N and C–O–C groups respectively of the oxdiazole
ring. The absence of absorption bands at 3233 and 1694 cm−1
due to the NH and C=O groups of the starting dihydrazide
clearly indicated the formation of cyclised products. In the
1H NMR spectrum of compound 7a, the the pyridine group
resonated as three signals at δ 9.10, 8.82 and 8.34, respectively.
The aromatic protons appeared as two multiplets in the region
δ 8.17–8.25 and δ 7.68–7.69 integrating for 10 protons. The
structures of newly synthesised bisoxdiazoles were also
confirmed by recording their mass spectra and elemental
analysis.
The biological activities of 7a–j are currently under further
investigation.
Experimental
Melting points were determined on a micro-melting point apparatus
and the thermometer was uncorrected. IR spectra were obtained on
1
1700 Perkin-Elmer FTIR using KBr disks. H NMR spectra were
recorded on a Varian INOVA 400 MHz spectrometer using DMSO-d6
as solvent and TMS as internal standard. Mass spectra were deter-
mined on Finnigan LCQDECA instrument. Elemental analysis was
performed on a Carlo-Erba-1106 autoanalyser. Microwave irradiation
was carried out with a MCL-3 microwave oven (very safe, reliable) at
full power (700 W), which was modified from domestic microwave
oven and tested to conform to the performance index before use. All
solvents were purified before use. The 1H NMR spectra of the hydra-
zides 6a–j and the 1,3,4-oxadiazoles 7a–j are given in the Electronic
Supplementary Information.
Result and discussion
Formation of the intermediates 2 and 3 proceeded cleanly in
nearly quantitative yields by microwave irradiation.19 The
pyridine-2,4-dihydrazides were synthesised by acylation of
substituted benzoylhydrazides with pyridine-2,4-dicarbonyl
chloride in the presence of pyridine. The reaction proceeded in
good yields (70–85%) and was moderated by ice water cool-
ing. Compared with the reported research20, which employed
the reaction of a pyridine dihydrazide with a substituted
benzoyl chloride in THF–pyridine solution, the reactants in
this approach both possess good solubility. In addition, the
solvent CH2Cl2 is less toxic than THF and the amount of
pyridine is significantly reduced.
The constitution of the pyridine-2,4-dihydrazides 6a–j was
confirmed by their IR, 1H NMR and mass spectra in addition to
elemental analysis. The IR spectrum of compound 6a showed
absorption bands at 3233 and 1694 cm−1corresponding to the
NH and C=O groups, respectively. The IR spectra of other
Preparation of benzoylhydrazides (3a–j)19
The aromatic acid (5 mmol), ethanol (15 mL) and thionyl chloride
(0.2 mL) were placed in a dried round-bottomed flask and the mixture
was subjected to microwave irradition (75 W) for 4 min. On comple-
tion of the reaction, the mixture was cooled to room temperature. The
excess thionyl chloride was removed. Then the reaction mixture was
added to 85% hydrazine hydrate (2 mL) and subjected to microwave
irradiation (75 W) for 3 min. The mixture was evaporated to give the
crude product. The crude product was recrystallised from ethanol to
give a pure sample.
Preparation of pyridine-2,4-dicarboxylic dihydrazides (6a–j)
Compound 3 (3 mmol), dichloromethane (10 mL) and pyridine
(0.2 mL) were placed in a dried round-bottomed flask and the mixture
was put in a beaker which was filled with ice water. A solution of 5
* Correspondent. E-mail: zzg63129@yahoo.com.cn

308 JOURNAL OF CHEMICAL RESEARCH 2010
Scheme 1
(1 mmol) in dichloromethane (5 mL) was added slowly to the mixture
and a solid was obtained. After the addition was complete, the reaction
mixture was kept for 2 h. The solid was collected by suction filtration
and washed with cold ethanol. The crude product was recrystallised to
give a pure sample. The progress of the reaction was monitored
by TLC. The physical and spectra data of the compounds 6a–j are as
follows.
H-3), 8.09 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.83–7.86 (4H, m,
ArH), 7.34 (4H, d, J = 8.0 Hz, ArH), 2.39 (6H, s, CH3); IR (KBr, cm−1
): 3238, 3033, 1695, 1653, 1499, 839, 744; ESI–MS m/z (%): 430
[(M-1)−, 100]. Anal. Calcd for C23H21N5O4; C, 64.03; H, 4.91; N,
16.23. Found; C, 63.88; H, 4.89; N, 16.28%.
6e: White solid, yield 79%, m.p. 261–262 °C; 1H NMR (400 MHz):
11.12 (1H, s, NH), 10.83 (1H, s, NH), 10.81 (1H, s, NH), 10.73(1H,
s, NH), 8.94 (1H, d, J = 5.2 Hz, pyridine H-6), 8.52 (1H, s, pyridine
H-3), 8.10 (1H, dd, J = 1.6, 4.8Hz, pyridine H-5), 7.94–7.97 (4H, m,
ArH), 7.61–7.64 (4H, m, ArH); IR (KBr, cm−1 ): 3234, 3024, 1692,
1651, 1599, 1564, 1487, 1453, 741; ESI–MS m/z (%): 470[(M-1)−,
100]. Anal. Calcd for C21H15Cl2N5O4; C, 53.41; H, 3.20; N, 14.83.
Found; C, 53.25; H, 3.21; N, 14.90%.
6a: White solid, yield 85%, m.p. 114–116 °C; 1H NMR (400 MHz):
11.08 (1H, s, NH), 10.79 (1H, s, NH), 10.69 (1H, s, NH), 10.62 (1H,
s, NH), 8.93 (1H, d, J = 5.2 Hz, pyridine H-6), 8.53 (1H, s, pyridine
H-3), 8.10 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.91–7.96 (4H, m,
ArH), 7.52–7.67 (6H, m, ArH); IR (KBr, cm−1 ): 3233, 3046, 1694,
1651, 1569, 1523, 872; ESI–MS m/z (%): 829 [(2M+23)+, 100]. Anal.
Calcd for C21H17N5O4; C, 62.53; H, 4.25; N, 17.36. Found; C, 62.37;
H, 4.26; N, 17.22%.
6f: White solid, yield 81%, m.p. 228–230 °C; 1H NMR (400 MHz):
11.01 (1H, s, NH), 10.73 (1H, s, NH), 10.54 (1H, s, NH), 10.47 (1H,
s, NH), 8.93 (1H, d, J = 4.8 Hz, pyridine H-6), 8.51 (1H, s, pyridine
H-3), 8.08 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.91–7.94 (4H, m,
ArH), 7.05–7.08 (4H, m, ArH), 3.84(6H, s, OCH3); IR (KBr, cm−1 ):
3226, 2976, 1693, 1648, 1571, 1519, 1252, 741; ESI–MS m/z (%):
949 [(2M+23)+, 100]. Anal. Calcd for C23H21N5O6; C, 59.61; H, 4.57;
N, 15.11. Found; C, 59.48; H, 4.58; N, 15.15%.
6b: White solid, yield 77%, m.p. 136–138 °C; 1H NMR (400 MHz):
11.36 (1H, s, NH), 10.81 (1H, s, NH), 10.21 (1H, s, NH), 10.17 (1H,
s, NH), 8.90 (1H, d, J = 4.8 Hz, pyridine H-6), 8.51(1H, s, pyridine
H-3), 8.07 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.79–7.83 (2H, m,
ArH), 7.57–7.63 (2H, m, ArH), 7.10–7.19 (4H, m, ArH), 3.90 (6H, s,
OCH3); IR (KBr, cm−1 ): 3269, 2977, 1696, 1648, 1598, 1479, 1242,
758; ESI–MS m/z (%): 462 [(M-1)−, 100]. Anal. Calcd for C23H21N5O6;
C, 59.61; H, 4.57; N, 15.11. Found; C, 59.38; H, 4.56; N, 15.15%.
6c: White solid, yield 74%, m.p. 117–119 °C; 1H NMR (400 MHz):
11.09 (1H, s, NH), 10.80 (1H, s, NH), 10.65 (1H, s, NH), 10.57 (1H,
s, NH), 8.94 (1H, d, J = 4.8 Hz, pyridine H-6), 8.52 (1H, s, pyridine
H-3), 8.09 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.73–7.76 (4H, m,
ArH), 7.41–7.43 (4H, m, ArH), 2.39 (6H, s, CH3); IR (KBr, cm−1 ):
3237, 3036, 1693, 1651, 1518, 816, 737, 682; ESI–MS m/z (%): 430
[(M-1)−, 100]. Anal. Calcd for C23H21N5O4; C, 64.03; H, 4.91; N,
16.23. Found; C, 63.85; H, 4.90; N, 16.18%.
6g: White solid, yield 72%, m.p. 230–232 °C; 1H NMR (400 MHz):
11.21 (1H, s, NH), 10.91 (1H, s, NH), 10.67 (1H, s, NH), 10.58 (1H,
s, NH), 8.98 (1H, d, J = 4.8 Hz, pyridine H-6), 8.65 (1H, s, pyridine
H-3), 8.41–8.47 (2H, m, ArH, pyridine H-5), 8.01–8.17 (5H, m, ArH),
7.59–7.76 (8H, m, ArH); IR (KBr, cm−1 ): 3344, 3190, 3047, 1703,
1602, 1478, 778, 659; ESI–MS m/z (%): 502 [(M-1)−, 100]. Anal.
Calcd for C29H21N5O4; C, 69.18; H, 4.20; N, 13.91. Found; C, 69.38;
H, 4.21; N, 13.87%.
6h: White solid, yield 81%, m.p. 285–287 °C; 1H NMR (400 MHz):
11.12 (1H, s, NH), 10.84 (1H, s, NH), 10.81 (1H, s, NH), 10.73 (1H,
s, NH), 8.94 (1H, d, J = 4.8 Hz, pyridine H-6), 8.51 (1H, s, pyridine
H-3), 8.09 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.86–7.89 (4H, m,
ArH), 7.75–7.78 (4H, m, ArH); IR (KBr, cm−1 ): 3205, 2980, 1690,
6d: White solid, yield 83%, m.p. 244–245 °C; 1H NMR (400 MHz):
11.02 (1H, s, NH), 10.72 (1H, s, NH), 10.59 (1H, s, NH), 10.53 (1H,
s, NH), 8.93 (1H, d, J = 4.8 Hz, pyridine H-6), 8.51 (1H, s, pyridine

JOURNAL OF CHEMICAL RESEARCH 2010 309
1635, 1599, 1554, 1463, 1073, 742; ESI–MS m/z (%): 560 [(M-1)−,
100]. Anal. Calcd for C21H15Br2N5O4; C, 44.95; H, 2.69; N, 12.48.
Found; C, 44.80; H, 2.68; N, 12.45%.
2,4-Bis[5-(1-naphthyl)-1,3,4-oxadiazol-2-yl]pyridine (7g): Brown
solid, yield 74%, m.p. 190–192 °C; 1H NMR (400 MHz): 9.00 (1H, d,
J = 4.8 Hz, pyridine H-6), 8.79–8.83 (2H, m, ArH, pyridine H-5), 8.57
(1H, s, pyridine H-3), 8.04–8.26 (7H, m, ArH), 7.65–7.76 (6H, m,
ArH); IR (KBr, cm−1 ): 3054, 1666, 1568, 1520, 1451, 1197, 769;
ESI–MS m/z (%): 468 [(M+1)+, 50]. Anal. Calcd for C29H17N5O2; C,
74.51; H, 3.67; N, 14.98. Found; C, 74.72; H, 3.68; N, 14.94%.
6i: White solid, yield 78%, m.p. 202–203 °C; 1H NMR (400 MHz):
11.41 (1H, s, NH), 10.86 (1H, s, NH), 10.26 (1H, s, NH), 10.23 (1H,
s, NH), 8.91 (1H, d, J = 5.2 Hz, pyridine H-6), 8.54 (1H, s, pyridine
H-3), 8.10 (1H, d, J = 4.8 Hz, pyridine H-5), 7.78–7.84 (2H, m, ArH),
7.51–7.55 (2H, m, ArH), 7.08–7.22 (4H, m, ArH), 4.21–4.28 (4H, m,
OCH2), 1.42–1.47 (6H, m, CH3); IR (KBr, cm−1 ): 3221, 2981, 2893,
1654, 1604, 1540, 1392, 760; ESI–MS m/z (%): 983 [(2M+1)+, 100].
Anal. Calcd for C25H25N5O6; C, 61.09; H, 5.13; N, 14.25. Found; C,
61.32; H, 5.12; N, 14.22%.
2,4-Bis[5-(4-bromophenyl)-1,3,4-oxadiazol-2-yl]pyridine
(7h):
Green solid, yield 78%, m.p. 226–228 °C; 1H NMR (400 MHz):
9.00 (1H, d, J = 4.8 Hz, pyridine H-6), 8.63 (1H, s, pyridine H-3),
8.36 (1H, d, J = 4.8 Hz, pyridine H-5), 8.24 (2H, d, J = 8.0 Hz, ArH),
8.16 (2H, d, J = 8.0 Hz, ArH), 7.67 (4H, d, J = 8.4 Hz, ArH); IR (KBr,
cm−1 ): 3066, 1597, 1534, 1474, 1267, 1076, 834; ESI–MS m/z (%):
524 [(M+1)+, 40]. Anal. Calcd for C21H11Br2N5O2; C, 48.03; H, 2.11;
N, 13.34. Found; C, 47.91; H, 2.12; N, 13.31%.
6j: White solid, yield 70%, m.p. 270–271 °C; 1H NMR (400 MHz):
11.09 (1H, s, NH), 10.79 1H, s, NH), 10.74 (1H, s, NH), 10.67 (1H, s,
NH), 8.95 (1H, d, J = 5.2 Hz, pyridine H-6), 8.55 (1H, s, pyridine
H-3), 8.11 (1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.99–8.06 (4H, m,
ArH), 7.74–7.86 (8H, m, ArH), 7.41–7.54 (6H, m, ArH); IR (KBr,
cm−1 ): 3225, 3034, 1692, 1649, 1562, 1523, 854, 739, 686; ESI–MS
m/z (%): 1133 [(2M+23)+, 100]. Anal. Calcd for C33H25N5O4; C, 71.34;
H, 4.54; N, 12.61. Found; C, 71.11; H, 4.55; N, 12.58%.
2,4-Bis[5-(2-ethoxyphenyl)-1,3,4-oxadiazol-2-yl]pyridine
(7i):
Brown solid, yield 67%, m.p. 172–174 °C; 1H NMR (400 MHz): 9.00
(1H, d, J = 4.8 Hz, pyridine H-6), 8.50 (1H, s, pyridine H-3), 7.94
(1H, dd, J = 1.6, 4.8 Hz, pyridine H-5), 7.85–7.90 (2H, m, ArH),
7.63–7.69 (2H, m, ArH), 7.16–7.26 (4H, m, ArH), 4.17–4.25 (4H, m,
OCH2), 1.23–1.31 (6H, m, CH3); IR (KBr, cm−1 ): 3067, 2982, 1604,
1535, 1467, 1398, 1240, 1039, 756; ESI–MS m/z (%): 456 [(M+1)+,
100]. Anal. Calcd for C25H21N5O4; C, 65.93; H, 4.65; N, 15.38. Found;
C, 66.12; H, 4.64; N, 15.33%.
Preparation of 2,4-bis(5-aryl-1,3,4-oxadiazol-2-yl)pyridines (7a–j)
A mixture of compound 6 (1 mmol) and phosphorus oxychloride
(10 mL) was heated under reflux for 15 h. Excess phosphorus oxy-
chloride was then distilled off and the residue was poured onto crushed
ice with vigorous stirring. The resulting solid was washed with cold
water, dilute NaHCO3 solution and then recrystallised from a mixture
of dimethylformamide and water. The characterisation data of title
compounds 7a–j are as follows.
2,4-Bis[5-(4-biphenyl)-1,3,4-oxadiazol-2-yl]pyridine (7j): Green
solid, yield 70%, m.p. 204–205 °C; 1H NMR (400 MHz): 9.02 (1H, d,
J = 4.8 Hz, pyridine H-6), 8.81 (1H, s, pyridine H-3), 8.32 (1H, d,
J = 4.8 Hz, pyridine H-5), 7.95–8.01 (4H, m, ArH), 7.83 (4H, d,
J = 8.0 Hz, ArH), 7.69–7.76 (4H, m, ArH), 7.46–7.56 (6H, m, ArH);
IR (KBr, cm−1 ): 3059, 1602, 1476, 1272, 1081, 848, 735; ESI–MS
m/z (%): 520 [(M+1)+, 45]. Anal. Calcd for C33H21N5O2; C, 76.29; H,
4.07; N, 13.48. Found; C, 76.50; H, 4.09; N, 13.44%.
2,4-Bis[5-phenyl-1,3,4-oxadiazol-2-yl]pyridine (7a): Green solid,
yield 80%, m.p. 220–222 °C; 1H NMR (400 MHz): 9.10 (1H, d,
J = 4.8 Hz, pyridine H-6), 8.82 (1H, s, pyridine H-3), 8.34 (1H, d,
J = 4.8 Hz, pyridine H-5), 8.17–8.25 (4H, m, ArH), 7.68–7.69 (6H, m,
ArH); IR (KBr, cm−1 ): 3060, 1604, 1539, 1442, 1076, 775, 701;
ESI–MS m/z (%): 368 [(M+1)+, 70]. Anal. Calcd for C21H13N5O2; C,
68.66; H, 3.57; N, 19.06. Found; C, 68.45; H, 3.56; N, 19.11%.
2,4-Bis[5-(2-methoxyphenyl)-1,3,4-oxadiazol-2-yl]pyridine (7b):
Brown solid, yield 70%, m.p. 166–168 °C; 1H NMR (400 MHz): 9.08
(1H, d, J = 4.8 Hz, pyridine H-6), 8.73 (1H, s, pyridine H-3), 8.26
(1H, d, J = 4.8 Hz, pyridine H-5), 8.04–8.08 (2H, m, ArH), 7.61–7.63
(2H, m, ArH), 7.33–7.36 (4H, m, ArH), 3.97 (6H, s, OCH3); IR (KBr,
cm−1 ): 3072, 2933, 1599, 1533, 1467, 1380, 1257, 1014, 756;
ESI–MS m/z (%): 428 [(M+1)+, 50]. Anal. Calcd for C23H17N5O4; C,
64.63; H, 4.01; N, 16.39. Found; C, 64.82; H, 4.02; N, 16.36%.
2,4-Bis[5-(3-methylphenyl)-1,3,4-oxadiazol-2-yl]pyridine (7c):
Green solid, yield 75%, m.p. 155–156 °C; 1H NMR (400 MHz): 9.00
(1H, d, J = 4.8 Hz, pyridine H-6), 8.81 (1H, s, pyridine H-3), 8.35
(1H, d, J = 4.8 Hz, pyridine H-5), 8.02–8.05 (4H, m, ArH), 7.39–7.43
(4H, m, ArH), 2.50 (6H, s, CH3); IR (KBr, cm−1 ): 3058, 2921, 1601,
1541, 1471, 1377, 1201, 1082, 731; ESI–MS m/z (%): 791 [(2M+1)+,
60]. Anal. Calcd for C23H17N5O2; C, 69.86; H, 4.33; N, 17.71. Found;
C, 70.08; H, 4.34; N, 17.68%.
2,4-Bis[5-(4-methylphenyl)-1,3,4-oxadiazol-2-yl]pyridine (7d):
Brown solid, yield 80%, m.p. 178–179 °C; 1H NMR (400 MHz): 9.08
(1H, d, J = 4.8 Hz, pyridine H-6), 8.80 (1H, s, pyridine H-3), 8.32
(1H, d, J = 4.8, pyridine H-5), 8.06–8.14 (4H, m, ArH),7.49 (4H, d,
J = 8.0, ArH), 2.38 (6H, s, CH3); IR (KBr, cm−1 ): 3033, 2921, 1608,
1533, 1492, 1379, 1081, 737; ESI–MS m/z (%): 813 [(2M+23)+, 65].
Anal. Calcd for C23H17N5O2; C, 69.86; H, 4.33; N, 17.71. Found; C,
70.05; H, 4.30; N, 17.66%.
2,4-Bis[5-(4-chlorphenyl)-1,3,4-oxadiazol-2-yl]pyridine(7e):Brown
solid, yield 82%, m.p. 267–268 °C; 1H NMR (400 MHz): 9.00 (1H, d,
J = 4.8 Hz, pyridine H-6), 8.63 (1H, s, pyridine H-3), 8.36 (1H, dd,
J = 1.6, 4.8 Hz, pyridine H-5), 7.75 (4H, d, J = 8.4 Hz, ArH),7.63
(4H, d, J = 8.8 Hz, ArH); IR (KBr, cm−1 ): 3004, 1600, 1534, 1476,
1274, 1090, 835, 732; ESI–MS m/z (%): 436 [(M+1)+, 40]. Anal.
Calcd for C21H11Cl2N5O2; C, 57.82; H, 2.54; N, 16.05. Found; C,
57.68; H, 2.53; N, 16.01%.
We thank the Natural Science Foundation of the State Ethnic
Affairs Commission of P.R.China (Project No.09XN08) for
the financial support.
Received 18 March 2010; accepted 17 May 2010
Paper 1000003 doi: 10.3184/030823410X12747104952034
Published online: 1 July 2010
References
1
S.V. Bhandari, K.G. Bothara, M.K. Raut, A.A. Patil, A.P. Sarkate and V.J.
Mokale, Bioorg. Med. Chem., 2008, 16, 1822.
2
3
S. Rollas, N. Gulerman and H. Erdeniz, Il Farmaco, 2002, 57, 171.
F. Liu, X.Q. Luo, B.A. Song, P.S. Bhadury, S. Yang, L.H. Jin, W. Xue and
D.Y. Hu, Bioorg. Med. Chem., 2008, 16, 3632.
4
A. Almasirad, S.A. Tabatabai, M. Faizi, A. Kebriaeezadeh, N. Mehrabi,
A. Dalvandia and A. Shafiee, Bioorg. Med. Chem., 2004, 14, 6057.
M. Tyagi and A. Kumar, Oriental J.Chem., 2002, 18, 125.
D. Kumar, S. Sundaree, E.O. Johnson and K. Shah, Bioorg. Med. Chem.
Lett., 2009, 19, 4492.
5
6
7
K.A. Milinkevich, C.L. Yoo, T.C. Sparks, B.A. Lorsbach and M.J. Kurth,
Bioorg. Med. Chem. Lett., 2009, 07, 139.
8
9
S.Y. Ke, Z. Li and X.H. Qian, Bioorg. Med. Chem., 2008, 16, 7565.
T.V. Hughes, G.Z. Xu, S.K. Wetter, P.J. Connolly, S.L. Emanuel,
P. Karnachi, S.R. Pollack, N. Pandey, M. Adams, S.M. Mazza, S.A.
Middleton and L.M. Greenberger, Bioorg. Med. Chem. Lett., 2008, 18,
4896.
10 R.N. Warrener, Eur. J. Org. Chem., 2000, 65, 3363.
11 C.R.W. Guimaraes, D.L. Boger and W.L. Jorgensen, J. Am. Chem. Soc.,
2005, 127, 17377.
12 N.J. Xiang,Y. Xu, W.L. Liang and M.X. Gong, Chem. J. Chin. Univ., 2008,
12, 2316.
13 G.S. Liou, N.K. Huang and Y.L. Yang, Eur. Polym. J., 2006, 42, 2283.
14 M. Guan, Z.Q. Bian, Y.F. Zhou, F.Y. Li, Z.J. Li and C.H. Huang, Chem.
Commun., 2003, 2708.
15 M.M. Ghorab, A.M.Sh. El-Sharief, Y.A. Ammar and Sh.I. Mohamed,
2,4-Bis[5-(4-methoxyphenyl)-1,3,4-oxadiazol-2-yl]pyridine (7f):
Brown solid, yield 76%, m.p. 210–212 °C; 1H NMR (400 MHz): 8.98
(1H, d, J = 4.8 Hz, pyridine H-6), 8.79 (1H, s, pyridine H-3), 8.32
(1H, d, J = 4.8 Hz, pyridine H-5), 7.82 (4H, d, J = 8.4 Hz, ArH), 7.03
(4H, d, J = 8.8 Hz, ArH), 3.85(6H, s, OCH3); IR (KBr, cm−1 ): 3066,
2932, 1605, 1492, 1428, 1379, 1255, 1172, 1021, 838; ESI–MS m/z
(%): 428 [(M+1)+, 58]. Anal. Calcd for C23H17N5O4; C, 64.63; H, 4.01;
N, 16.39. Found; C, 64.75; H, 4.00; N, 16.42%.
Il Farmaco, 2000, 55, 354.
16 B.S. Holla, K.N. Poojary, B.S. Rao and M.K. Shivananda, Eur. J. Med.
Chem., 2002, 37, 511.
17 K. Meng and Y. Qian, Chin. Org. Chem., 2009, 29, 71.
18 C.J. Liu, T.H. Shi and Y.P. Li, Chin. Org. Chem., 2007, 27, 985.
19 W.J. Li, X.Q. Wang, Z.G. Zhao and T. Han, J. Chem. Res., 2010, 2, 106.
20 C.S. Wang, G.Y. Jung, A.S. Batsanov, M.R. Bryce and M.C. Petty, J. Mater.
Chem., 2002, 12, 173.

Copyright of Journal of Chemical Research is the property of Science Reviews 2000 Ltd. and its content may
not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written
permission. However, users may print, download, or email articles for individual use.