Synthesis of 1,2,4- and 1,3,4-oxadiazoles from 1-aryl-5-methyl-1H-1,2,3- triazole-4-carbonyl chlorides

Article abstract of DOI:10.1134/S1070428008100217

5-Substituted 2-(1-aryl-5-methyl-1H-1,2,3-triazol-4-yl)-1,3,4-oxadiazoles were synthesized by reaction of 1-aryl-5-methyl-1H-1,2,3-triazole-4-carbonyl chlorides with the corresponding 5-substituted 1H-tetrazoles. 5-Methyl-1-phenyl-1H-1,2,3-triazole-4-carb

Full text of DOI:10.1134/S1070428008100217

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 10, pp. 1522–1527. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © N.D. Obushak, N.T. Pokhodylo, N.I. Pidlypnyi, V.S. Matiichuk, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44,
No. 10, pp. 1544–1549.
Synthesis of 1,2,4- and 1,3,4-Oxadiazoles from 1-Aryl-5-methyl-
1H-1,2,3-triazole-4-carbonyl Chlorides
N. D. Obushak, N. T. Pokhodylo, N. I. Pidlypnyi, and V. S. Matiichuk
Ivan Franko Lviv National University, ul. Kirilla i Mefodiya 6, Lviv, 79005 Ukraine
e-mail: obushak@in.lviv.ua
Received January 14, 2008
Abstract—5-Substituted 2-(1-aryl-5-methyl-1H-1,2,3-triazol-4-yl)-1,3,4-oxadiazoles were synthesized by re-
action of 1-aryl-5-methyl-1H-1,2,3-triazole-4-carbonyl chlorides with the corresponding 5-substituted 1H-tetra-
zoles. 5-Methyl-1-phenyl-1H-1,2,3-triazole-4-carbonyl chloride reacted with N′-hydroxybenzimidamides to
give 3-aryl-5-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1,2,4-oxadiazoles. Reactions of 4-(5-methyl-1H-1,2,3-
triazol-1-yl)benzoic acid with N′-hydroxybenzimidamides resulted in the formation of 3-aryl-5-[4-(5-methyl-
1H-1,2,3-triazol-1-yl)phenyl]-1,2,4-oxadiazoles.
DOI: 10.1134/S1070428008100217
1,3,4-Oxadiazoles constitute an important class of
heterocyclic compounds [1]. Numerous 1,3,4-oxadia-
zole derivatives exhibit biological activity, in particular
antiphlogistic and hypotensive [2], bactericidal [3],
hypoglycemic [4], myorelaxant [5], fungicidal [6],
insecticidal [7], and pesticidal [8]. Central nervous
system stimulators were found among 1,3,4-oxadiazole
derivatives [9], and such medical agents as Vadrin,
Eudormil, and SC27166 are based on compounds of
this class [10–12]. 1,2,4-Oxadiazoles have also found
application, e.g., as hydrolytically stable bioisosters of
amide and ester groups [13], antidepressants [14],
5-HT1D receptor agonists [15], and antiviral agents
[16]. Compounds containing a 1,2,3-triazole ring also
possess biological activity [17].
is accompanied by thermal rearrangement with libera-
tion of nitrogen (Scheme 1). However, it is more likely
that elimination of nitrogen molecule and formation of
oxadiazole ring follow a synchronous mechanism [19].
Analogous reactions of triazolecarboxylic acid chlo-
rides were not reported. Such reactions might be ex-
pected to involve competing processes due to opening
of the triazole ring with formation of highly reactive
intermediates.
We have found that 5-substituted tetrazoles VIa–
VIe react with 1-aryl-5-methyl-1H-1,2,3-triazole-4-
carbonyl chlorides IVa–IVg to give in all cases the
corresponding 1,3,4-oxadiazoles VIIa–VIIu having
a triazolyl substituent in the 5-position. The reactions
start at a temperature of about 60°C and are complete
in 30 min, and the yields of compounds VIIa–VIIu
range from 54 to 83% (Scheme 2). Initial tetrazoles
VIa–VIe were obtained by 1,3-dipolar cycloaddition
of sodium azide to nitriles Va–Ve [20], and triazolecar-
boxylic acids IIIa–IIIg were prepared by cycloaddi-
tion of aryl azides IIa–IIg to ethyl acetoacetate. Com-
pounds IIa–IIg were synthesized in turn from substi-
tuted anilines Іa–Ig via diazotization followed by
treatment with sodium azide.
In the present work we tried to find synthetic
approaches to compounds including both 1,2,3-triazole
and oxadiazole fragments. It is known that 2,5-disub-
stituted 1,3,4-oxadiazoles can be obtained by reaction
of carboxylic acid chlorides with tetrazoles [18], which
Scheme 1.
R2
N
N
O
N
O
N
+
R2
N
N
N
R1
Cl
We also examined reactions of acid chloride IVa
with N′-hydroxybenzimidamides IXa–IXc. The reac-
tions were carried out in pyridine at room temperature,
and the mixture was then heated in DMF for 3 h at
80°C. These conditions allowed us to avoid decom-
R1
N
H
N
N
O
N
N
R2
R1
R2
–N2
O
R1
1522

SYNTHESIS OF 1,2,4- AND 1,3,4-OXADIAZOLES
1523
Scheme 2.
N
N
(1) NaNO2, HCl
(2) NaN3
MeCOCH2COOEt
NaOMe, MeOH
NH2
N3
R1
N
COOH
R1
R1
Me
IIIa–IIIg
Ia–Ig
IIa–IIg
N
N
N
N
O
R1
R1
N
N
R2
SOCl2, dioxane
VIa–VIe, pyridine, Δ
COCl
N
N
Me
IVa–IVg
Me
VIIa–VIIu
N
N
N
N
NaN3, NH4Cl, DMF
R2CN
N
HN
R2
R2
N
N
H
Va–Ve
VIa–VIe
I–IV, R1 = H (a), 2-Me (b), 3-Me (c), 4-Me (d), 4-F (e), 2-MeO (f), 3-MeO (g); V, VI, R2 = Ph (a), 2-MeC6H4 (b), 4-MeC6H4 (c),
2-ClC6H4 (d), 2-furyl (e); VII, R1 = H, R2 = Ph (a), 2-MeC6H4 (b), 4-MeC6H4 (c), 2-ClC6H4 (d), 2-furyl (e); R1 = 2-Me, R2 = Ph (f),
4-MeC6H4 (g), 2-furyl (h); R1 = 3-Me, R2 = Ph (i), 2-MeC6H4 (j); R1 = 4-Me, R2 = Ph (k), 2-MeC6H4 (l), 4-MeC6H4 (m), 2-furyl (n);
R1 = 4-F, R2 = Ph (o), 2-MeC6H4 (p), 2-furyl (q); R1 = 2-MeO, R2 = Ph (r), 4-MeC6H4 (s); R1 = 3-MeO, R2 = Ph (t), 2-MeC6H4 (u).
position of the triazole ring and tarring; as a result,
almost no by-products were formed, and compounds
Xa and Xb were isolated in high yields (Scheme 3).
Thus the proposed procedure may be regarded as
a preparative method of synthesis of compounds
simultaneously containing both 1,2,3-triazole and
1,2,4-oxadiazole fragments. N′-Hydroxybenzimid-
amides IXa–IXc were synthesized by addition of hy-
droxylamine to nitriles VIIIa–VIIIc.
EXPERIMENTAL
1
The H NMR spectra were measured on a Varian
Mercury spectrometer (400 MHz) using DMSO-d6 as
solvent and tetramethylsilane as internal reference.
Aryl azides ІIa–IIh were synthesized according to
the procedure reported in [21]: ІIa, yield 63%, bp 52–
53°C (10 mm); IІb, yield 46%, bp 62°C (10 mm); IІc,
yield 67%, bp 78°C (10 mm); IІd, yield 70%, bp 70°C
(10 mm); IІe, yield 78%; ІIf, yield 57%, bp 87–89°C
(1 mm); IІg, yield 78%; ІIh, yield 87%, mp 179–
180°C (from aqueous ethanol); azides IIe and IIg were
used without additional purification.
Acids ІІIa–IIIg were prepared as described in [22]
and were purified by recrystallization from aqueous
alcohol: ІІІa, yield 84%, mp 137–138°C; ІІІb, yield
65%, mp 134–135°C; ІІІc, yield 54%, mp 158–159°C;
ІІІd, yield 76%, mp 183–184°C; ІІІe, yield 88%,
mp 187–188°C; ІІІf, yield 63%, mp 175–176°C; ІІІg,
yield 68%, mp 133–134°C.
Compounds containing 1,2,4-oxadiazole and tri-
azole rings were also obtained starting from triazolyl-
substituted benzoic acid XII which was synthesized
from 4-azidobenzoic acid (IIh) and phosphorane XI.
The corresponding acid chloride XIII smoothly re-
acted with amide oximes IXb and IXc, yielding com-
pounds XIVa and XIVb, respectively (Scheme 4).
Thus the results of our study demonstrate the pos-
sibility for synthesizing molecular ensembles including
oxadiazole and triazole rings in different combinations
by reactions of triazolecarboxylic acid chlorides with
tetrazoles or N′-hydroxybenzimidamides.
Acid chlorides ІVa–IVg and XIII (general proce-
dure). A mixture of 50 mmol of the corresponding
Scheme 3.
OH
N
N
N
R
NH2OH·HCl
EtOH–H2O, Na2CO3
CN
N
N
NH2 IVa, pyridine, DMF
Ph
O
N
Me
R
R
VIIIa–VIIIc
IXa–IXc
Xa, Xb
VIII, IX, R = H (a), Me (b), Cl (c); X, R = H (a), Me (b).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 10 2008

OBUSHAK et al.
1524
Scheme 4.
Me
COOH
COOH
O
Et3N, PhH, Δ
Ph3P
COCl
+
N
Me
N3
N
N
IIh
XI
XII
O
N
Me
Me
SOCl2, dioxane
IXb, IXc, pyridine, DMF
N
N
N
R
N
N
N
N
XIII
XIVa, XIVb
XIV, R = Me (a), Cl (b).
1
carboxylic acid and 4.4 ml (60 mmol) of thionyl chlo-
ride in 30 ml of dioxane was heated under reflux until
hydrogen chloride no longer evolved. The mixture was
cooled to room temperature, 30 ml of hexane was
added, and the precipitate was filtered off, washed with
hexane on a filter, and dried in air: ІVa, yield 95%,
mp 126–127°C; ІVb, yield 89%, mp 143–144°C; ІVc,
yield 91%, mp 75–76°C; ІVd, yield 97%, mp 142–
143°C; ІVe, yield 96%, mp 85–86°C; ІVf, yield 84%,
mp 122–123°C; ІVg, yield 88%, mp 125–126°C; XIII,
yield 63%, mp 175–176°C.
Tetrazoles VIa–VIe were synthesized according to
the procedure described in [20]: VIa, yield 82%,
mp 218–219°C; VIb, yield 61%, mp 150–151°C; VIc,
yield 87%, mp 257–258°C; VId, yield 74%, mp 176–
177°C; VIe, yield 75%, mp 201–202°C.
N′-Hydroxybenzimidamides IXa–IXc were pre-
pared as described in [23]: IXa, yield 70%, mp 71°C;
IXb, yield 83%, mp 155°C; IXc, yield 72%, mp 129°C.
4-Azidobenzoic acid (XII) was obtained as de-
scribed in [24]. Yield 82%, mp 243–244°C.
1,3,4-Oxadiazoles VIIa–VIIu (general procedure).
Acid chloride ІVa–IVg, 5 mmol, was added to a solu-
tion of 5 mmol of tetrazole VIa–VIe in 5 ml of pyr-
idine. The mixture was heated until nitrogen no longer
evolved, heated for 30 min under reflux, cooled, and
diluted with 50 ml of water. The precipitate was fil-
tered off, washed on a filter with water (up to 50 ml),
dried in air, and purified by recrystallization.
63%, mp 149°C. H NMR spectrum, δ, ppm: 2.72 s
(3H, Me), 2.75 s (3H, Me), 7.38–7.52 m (3H, Harom),
7.62–7.68 m (5H, Harom), 8.04 d (1H, 6-H, J = 7.6 Hz).
Found, %: C 68.22; H 4.82; N 21.95. C18H15N5O. Cal-
culated, %: C 68.13; H 4.76; N 22.07.
2-(4-Methylphenyl)-5-(5-methyl-1-phenyl-1H-
1,2,3-triazol-4-yl)-1,3,4-oxadiazole (VIIc). Yield
1
78%, mp 155°C. H NMR spectrum, δ, ppm: 2.47 s
(3H, Me), 2.72 s (3H, Me), 7.41 d (2H, 3-H, 5-H in
4-MeC6H4, J = 8.0 Hz), 7.62–7.69 m (5H, C6H5),
8.02 d (2H, 2-H, 6-H in 4-MeC6H4, J = 8.0 Hz).
Found, %: C 67.84; H 4.66; N 22.15. C18H15N5O. Cal-
culated, %: C 68.13; H 4.76; N 22.07.
2-(2-Chlorophenyl)-5-(5-methyl-1-phenyl-1H-
1,2,3-triazol-4-yl)-1,3,4-oxadiazole (VIId). Yield
1
59%, mp 145°C. H NMR spectrum, δ, ppm: 2.73 s
(3H, Me), 7.57 pseudotriplet (1H, 4-H in C6H4), 7.61–
7.69 m (7H, Harom), 8.10 d (1H, 6-H in C6H4, J =
8.0 Hz). Found, %: C 60.49; H 3.50; N 20.87.
C17H12ClN5O. Calculated, %: C 60.45; H 3.58; N 20.73.
2-(2-Furyl)-5-(5-methyl-1-phenyl-1H-1,2,3-tri-
azol-4-yl)-1,3,4-oxadiazole (VIIe). Yield 70%,
mp 137°C. H NMR spectrum, δ, ppm: 2.72 s (3H,
Me), 6.76 d.d (1H, 4′-H, J = 1.6, 3.2 Hz), 7.38 d (1H,
3′-H, J = 3.2 Hz), 7.62–7.69 m (5H, Harom), 7.99 d (1H,
5′-H, J = 1.6 Hz). Found, %: C 61.09; H 3.65; N 23.91.
C15H11N5O2. Calculated, %: C 61.43; H 3.78; N 23.88.
1
2-[5-Methyl-1-(2-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-phenyl-1,3,4-oxadiazole (VIIf). Yield
2-(5-Methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-
5-phenyl-1,3,4-oxadiazole (VIIa). Yield 79%,
1
72%, mp 144°C. H NMR spectrum, δ, ppm: 2.09 s
1
(3H, Me), 2.53 s (3H, Me), 7.42–7.64 m (7H, Harom),
8.13–8.16 m (2H, Harom). Found, %: C 68.01; H 4.82;
N 21.94. C18H15N5O. Calculated, %: C 68.13; H 4.76;
N 22.07.
mp 137°C. H NMR spectrum, δ, ppm: 2.73 s (3H,
Me), 7.60–7.70 m (8H, Harom), 8.14 m (2H, Harom).
Found, %: C 67.14; H 4.41; N 22.98. C17H13N5O. Cal-
culated, %: C 67.32; H 4.32; N 23.09.
2-[5-Methyl-1-(2-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-(4-methylphenyl)-1,3,4-oxadiazole
2-(2-Methylphenyl)-5-(5-methyl-1-phenyl-1H-
1,2,3-triazol-4-yl)-1,3,4-oxadiazole (VIIb). Yield
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 10 2008

SYNTHESIS OF 1,2,4- AND 1,3,4-OXADIAZOLES
1525
1
(VIIg). Yield 74%, mp 127°C. H NMR spectrum, δ,
ppm: 2.09 s (3H, Me), 2.46 s (3H, Me), 2.52 s (3H,
Me), 7.41 d (2H, 3-H, 5-H in 4-MeC6H4, J = 8.0 Hz),
7.46 d (1H, 3-H in 2-MeC6H4, J = 8.0 Hz), 7.48–
7.59 m (3H, 2-MeC6H4), 8.02 d (2H, 2-H, 6-H in
4-MeC6H4, J = 8.0 Hz). Found, %: C 68.98; H 5.14;
N 21.01. C19H17N5O. Calculated, %: C 68.87; H 5.17;
N 21.13.
2-[5-Methyl-1-(4-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-(4-methylphenyl)-1,3,4-oxadiazole
(VIIm). Yield 82%, mp 186°C. H NMR spectrum, δ,
1
ppm: 2.46 s (3H, Me), 2.48 s (3H, Me), 2.69 s (3H,
Me), 7.41 (2H, 3-H, 5-H in C6H4N, J = 8.2 Hz),
7.45 (2H, 3-H, 5-H in C6H4, J = 8.0 Hz), 7.53 (2H,
2-H, 6-H in C6H4N, J = 8.2 Hz), 8.01 (2H, 2-H, 6-H
in C6H4, J = 8.0 Hz). Found, %: C 68.48; H 5.06;
N 21.09. C19H17N5O. Calculated, %: C 68.87; H 5.17;
N 21.13.
2-(2-Furyl)-5-[5-methyl-1-(2-methylphenyl)-1H-
1,2,3-triazol-4-yl]-1,3,4-oxadiazole (VIIh). Yield
1
2-(2-Furyl)-5-[5-methyl-1-(4-methylphenyl)-1H-
1,2,3-triazol-4-yl]-1,3,4-oxadiazole (VIIn). Yield
54%, mp 117°C. H NMR spectrum, δ, ppm: 2.08 s
(3H, Me), 2.50 s (3H, Me), 6.77 d.d (1H, 4′-H, J = 1.2,
3.6 Hz), 7.38 d (1H, 3′-H, J = 3.6 Hz), 7.42–7.58 m
(4H, C6H4), 7.99 d (1H, 5′-H, J = 1.2 Hz). Found, %:
C 62.45; H 4.19; N 22.85. C16H13N5O2. Calculated, %:
C 62.53; H 4.26; N 22.79.
1
79%, mp 174°C. H NMR spectrum, δ, ppm: 2.48 s
(3H, Me), 2.69 s (3H, Me), 6.76 d.d (1H, 4′-H, J = 1.6,
3.2 Hz), 7.38 d (1H, 3′-H, J = 3.2Hz), 7.44 d (2H, 3-H,
5-H in C6H4, J = 8.0 Hz), 7.53 d (2H, 2-H, 6-H
in C6H4, J = 8.0 Hz), 7.99 br.s (1H, 5′-H). Found, %:
C 62.41; H 4.21; N 22.70. C16H13N5O2. Calculated, %:
C 62.53; H 4.26; N 22.79.
2-[5-Methyl-1-(3-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-phenyl-1,3,4-oxadiazole (VIIi). Yield
1
76%, mp 119°C. H NMR spectrum, δ, ppm: 2.49 s
2-[1-(4-Fluorophenyl)-5-methyl-1H-1,2,3-triazol-
4-yl]-5-phenyl-1,3,4-oxadiazole (VIIo). Yield 79%,
(3H, Me), 2.72 s (3H, Me), 7.41–7.48 m (3H, C6H4),
7.52 pseudotriplet (1H, 5-H in C6H4), 7.58–7.63 m
(3H, C6H5), 8.12–8.16 m (2H, C6H5). Found, %:
C 68.22; H 4.85; N 22.13. C18H15N5O. Calculated, %:
C 68.13; H 4.76; N 22.07.
1
mp 169°C. H NMR spectrum, δ, ppm: 2.70 s (3H,
Me), 7.43 pseudotriplet (2H, 3-H, 5-H in 4-FC6H4),
7.58–7.62 m (3H, C6H5), 7.74 d.d (2H, 2-H, 6-H in
4-FC6H4, JHF = 4.8, JHH = 8.8 Hz), 8.11–8.14 m
(2H, C6H5). Found, %: C 63.61; H 3.63; N 21.78.
C17H12FN5O. Calculated, %: C 63.55; H 3.76; N 21.80.
2-[5-Methyl-1-(3-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-(2-methylphenyl)-1,3,4-oxadiazole
1
(VIIj). Yield 65%, mp 129°C. H NMR spectrum, δ,
2-[1-(4-Fluorophenyl)-5-methyl-1H-1,2,3-triazol-
ppm: 2.49 s (3H, Me), 2.71s (3H, Me), 2.75 s (3H,
Me), 7.39–7.56 m (7H, Harom), 8.05 d (1H, 6-H in
2-MeC6H4, J = 7.6 Hz). Found, %: C 68.53; H 5.07;
N 20.89. C19H17N5O. Calculated, %: C 68.87; H 5.17;
N 21.13.
4-yl]-5-(2-methylphenyl)-1,3,4-oxadiazole (VIIp).
1
Yield 83%, mp 127°C. H NMR spectrum, δ, ppm:
2.70 s (3H, Me), 2.74 s (3H, Me), 7.38–7.52 m (5H,
H
arom), 7.75 d.d (2H, 2-H, 6-H in 4-FC6H4, JHF = 4.8,
JHH = 8.8 Hz), 8.04 d (1H, 6-H in 2-MeC6H4, J =
7.6 Hz). Found, %: C 64.28; H 4.24; N 20.97.
C18H14FN5O. Calculated, %: C 64.47; H 4.21; N 20.88.
2-[5-Methyl-1-(4-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-phenyl-1,3,4-oxadiazole (VIIk). Yield
1
80%, mp 182°C. H NMR spectrum, δ, ppm: 2.48 s
2-[1-(4-Fluorophenyl)-5-methyl-1H-1,2,3-triazol-
4-yl]-5-(2-furyl)-1,3,4-oxadiazole (VIIq). Yield 75%,
(3H, Me), 2.70 s (3H, Me), 7.45 d (2H, 3-H, 5-H in
C6H4, J = 8.4 Hz), 7.53 d (2H, 2-H, 6-H in C6H4, J =
8.4 Hz), 7.60–7.63 m (3H, C6H5), 8.12–8.16 m (2H,
2-H, 6-H in C6H5). Found, %: C 67.80; H 4.71;
N 21.97. C18H15N5O. Calculated, %: C 68.13; H 4.76;
N 22.07.
1
mp 184°C. H NMR spectrum, δ, ppm: 2.70 s (3H,
Me), 6.77 d.d (1H, 4′-H, J = 1.2, 3.6 Hz), 7.39 d (1H,
3′-H, J = 3.6 Hz), 7.44 pseudotriplet (2H, 3-H, 5-H in
4-FC6H4), 7.74 d.d (2H, 2-H, 6-H in 4-FC6H4, JHF
=
4.8, JHH = 8.8 Hz), 7.99 d (1H, 5′-H, J = 1.2 Hz).
Found, %: C 57.61; H 3.28; N 22.41. C15H10FN5O2.
Calculated, %: C 57.88; H 3.24; N 22.50.
2-[5-Methyl-1-(4-methylphenyl)-1H-1,2,3-tri-
azol-4-yl]-5-(2-methylphenyl)-1,3,4-oxadiazole
1
(VIIl). Yield 74%, mp 148°C. H NMR spectrum, δ,
2-[1-(2-Methoxyphenyl)-5-methyl-1H-1,2,3-tri-
azol-4-yl]-5-phenyl-1,3,4-oxadiazole (VIIr). Yield
ppm: 2.48 s (3H, Me), 2.70 s (3H, Me), 2.75 s (3H,
Me), 7.39–7.56 m (7H, Harom), 8.05 d (1H, 6-H in
2-MeC6H4, J = 7.6Hz). Found, %: C 68.98; H 5.12;
N 21.22. C19H17N5O. Calculated, %: C 68.87; H 5.17;
N 21.13.
1
61%, mp 164°C. H NMR spectrum, δ, ppm: 2.49 s
(3H, Me), 3.89 s (3H, MeO), 7.19 pseudotriplet (1H,
5-H in C6H4), 7.32 d (1H, 3-H in C6H4, J = 8.4 Hz),
7.48 d (1H, 6-H in C6H4, J = 8.0 Hz), 7.58–7.66 m
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 10 2008

OBUSHAK et al.
1526
1
(4H, Harom), 8.12–8.15 m (2H, 2-H, 6-H in C6H5).
Found, %: C 64.69; H 4.46; N 20.93. C18H15N5O2. Cal-
culated, %: C 64.86; H 4.54; N 21.01.
mp 142°C. H NMR spectrum, δ, ppm: 2.48 s (3H,
Me), 2.77 s (3H, Me), 7.35 d (2H, Harom, J = 8.0 Hz),
7.64–7.69 m (5H, Harom), 8.01 d (2H, 2-H, 6-H in
C6H4, J = 8.0 Hz). Found, %: C 68.03; H 4.67;
N 21.95. C18H15N5O. Calculated, %: C 68.13; H 4.76;
N 22.07.
2-[1-(2-Methoxyphenyl)-5-methyl-1H-1,2,3-tri-
azol-4-yl]-5-(4-methylphenyl)-1,3,4-oxadiazole
1
(VIIs). Yield 72%, mp 135°C. H NMR spectrum, δ,
5-[4-(5-Methyl-1H-1,2,3-triazol-1-yl)phenyl]-3-
(4-methylphenyl)-1,2,4-oxadiazole (XІVa). Yield
75%, mp 176°C. H NMR spectrum, δ, ppm: 2.44 s
(3H, Me), 2.46 s (3H, Me), 7.35 d (2H, 3-H, 5-H in
4-MeC6H4, J = 7.8 Hz), 7.63 s (1H, 4′-H), 7.89 d (2H,
3-H, 5-H in C6H4, J = 8.4 Hz), 7.99 d (2H, 2-H, 6-H in
4-MeC6H4, J = 7.8 Hz), 8.39 d (2H, 2-H, 6-H in C6H4,
J = 8.4 Hz). Found, %: C 68.01; H 4.62; N 21.95.
C18H15N5O. Calculated, %: C 68.13; H 4.76; N 22.07.
ppm: 2.46 s (3H, Me), 2.52 s (3H, Me), 3.87 s (3H,
MeO), 7.19 pseudotriplet (1H, 5-H in 2-MeOC6H4),
7.33 d (1H, 3-H in 2-MeOC6H4, J = 8.4 Hz), 7.41 d
(2H, 3-H, 5-H in 4-MeC6H4, J = 7.8 Hz), 7.48 d (1H,
6-H in 2-MeOC6H4, J = 7.6 Hz), 7.64 pseudotriplet
(1H, 4-H in 2-MeOC6H4), 8.02 d (2H, 2-H, 6-H in
4-MeC6H4, J = 7.8 Hz). Found, %: C 65.72; H 4.80;
N 20.04. C19H17N5O2. Calculated, %: C 65.69; H 4.93;
N 20.16.
1
3-(4-Chlorophenyl)-5-[4-(5-methyl-1H-1,2,3-tri-
azol-1-yl)phenyl]-1,2,4-oxadiazole (XІVb). Yield
84%, mp 222°C. H NMR spectrum, δ, ppm: 2.43 s
2-[1-(3-Methoxyphenyl)-5-methyl-1H-1,2,3-tri-
azol-4-yl]-5-phenyl-1,3,4-oxadiazole (VIIt). Yield
78%, mp 129°C. H NMR spectrum, δ, ppm: 2.73 s
1
1
(3H, Me), 7.69 d (2H, 3-H, 5-H in 4-ClC6H4, J =
8.4 Hz), 7.76 s (1H, 4′-H), 7.94 d (2H, 3-H, 5-H in
C6H4, J = 8.4 Hz), 8.12 d (2H, 2-H, 6-H in 4-ClC6H4,
J = 8.4 Hz), 8.40 d (2H, 2-H, 6-H in C6H4, J = 8.4 Hz).
Found, %: C 60.32; H 3.50; N 20.54. C17H12ClN5O.
Calculated, %: C 60.45; H 3.58; N 20.73.
(3H, Me), 3.89 s (3H, MeO), 7.14–7.24 m (3H, Harom),
7.55 pseudotriplet (1H, Harom), 7.60–7.63 m (3H,
Harom), 8.13–8.16 m (2H, 2-H, 6-H in C6H5). Found, %:
C 64.94; H 4.62; N 20.86. C18H15N5O2. Calculated, %:
C 64.86; H 4.54; N 21.01.
2-[1-(3-Methoxyphenyl)-5-methyl-1H-1,2,3-tri-
azol-4-yl]-5-(2-methylphenyl)-1,3,4-oxadiazole
(VIIu). Yield 62%, mp 152°C. H NMR spectrum, δ,
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1
ppm: 2.72 s (3H, Me), 2.74 s (3H, Me), 3.88 s (3H,
MeO), 7.15–7.23 m (3H, Harom), 7.39–7.57 m (4H,
Harom), 8.07 d (1H, 6-H in 2-MeC6H4, J = 8.0 Hz).
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1H NMR spectrum, δ, ppm: 2.78 s (3H, Me), 7.55–
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SYNTHESIS OF 1,2,4- AND 1,3,4-OXADIAZOLES
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