Synthesis and evaluation on anticonvulsant and antidepressant activities of 5-alkoxy-tetrazolo[1,5-a]quinazolines

Article abstract of DOI:10.1002/ardp.200900119

Several 5-alkoxy-tetrazolo[1,5-a]quinazoline derivatives have been synthesized by reacting 2,4-dichloroquinazoline with various phenols or aliphatic alcohol and then with sodium azide. The structures of these compounds have been confirmed by IR, MS,

Full text of DOI:10.1002/ardp.200900119

Arch. Pharm. Chem. Life Sci. 2009, 342, 671–675
H.-J. Wang et al.
671
Full Paper
Synthesis and Evaluation on Anticonvulsant and
Antidepressant Activities of 5-Alkoxy-tetrazolo[1,5-
a]quinazolines
Huo-Jian Wang1, 2, Cheng-Xi Wei2, Xian-Qing Deng2, Fu-Lan Li2, and Zhe-Shan Quan1, 2
1 Institute of Neurosurgery, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia Autonomous
Region, P.R. China
2 College of Pharmacy, Yanbian University, Yanji, Jilin, P.R. China
Several 5-alkoxy-tetrazolo[1,5-a]quinazoline derivatives have been synthesized by reacting 2,4-
dichloroquinazoline with various phenols or aliphatic alcohol and then with sodium azide. The
structures of these compounds have been confirmed by IR, MS, 1H-NMR, and elementary analysis.
Anticonvulsant activities were evaluated using the maximal electroshock (MES) test. Most of the
synthesized compounds displayed weak anticonvulsant activity at a dose of 300 mg/kg. Antide-
pressant activities were investigated by forced swimming test. Two compounds, namely 5-(hexyl-
oxy)tetrazolo[1,5-a]quinazoline and 5-(4-methoxyphenoxy)tetrazolo[1,5-a]quinazoline, showed
significant antidepressant activity, which decreased the immobility time by 62.2 and 51.7% at
100 mg/kg dose level.
Keywords: Anticonvulsant / Antidepressant / Forced swimming test / Quinazoline / Tetrazole /
Received: June 1, 2009; Accepted: July 12, 2009
DOI 10.1002/ardp.200900119
Introduction
In our earlier studies, we reported that 6-alkyloxyl-3,4-
dihydro-2(1H)-quinolinones I showed good anticonvul-
sant activities in the maximal electroshock (MES) test [1].
In the following study, we introduced some heterocyclic
Figure 1. Structure of compound I, II, III, IV, and V.
rings to the first and second position of compounds I
such as triazoles II, triazolones III, and triazones IV
(Fig. 1) to investigate their contribution to the anticon-
vulsant activity [2–9]. Then, we researched the synthesis
and anticonvulsant activities of the compounds V (Fig. 1),
namely the bio-isoterism of compound II [10]. Research
results indicate that the introduction of a heterocyclic
ring to the first and second position of quinoline or
Scheme 1. The synthesis route of the compounds.
phthalazine cause a remarkable increase in anticonvul-
sant activity.
Consequently, as part of our continuous effort to find
better anticonvulsant agents among these compounds, a
series of new 5-alkoxy-tetrazolo[1,5-a]quinazolines were
synthesized as outlined in Scheme 1 and evaluated for
their anticonvulsant activity using the MES test. Some
interactions appear between anticonvulsant and antide-
pressant drugs [11]. For example, many anticonvulsants
possess an antidepressive-like effect such as oxcarbaze-
Correspondence: Zhe-Shan Quan, College of Pharmacy, Yanbian Uni-
versity, No. 121, JuZi Street, Yanji City, Jilin Province 133000, P.R. Chi-
na.
E-mail: zsquan@ybu.edu.cn
Fax: +86 433 266-0568
Abbreviations: forced swimming test (FST); maximal electroshock
(MES); monoamine oxidase (MAO)
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

672
H.-J. Wang et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 671–675
Table 1. Anticonvulsant activities of the compounds in MES.
pine [12], piperine [13], lamotrigine [14], and some antide-
pressants also exhibit anticonvulsant activity such as
doxepin [15]. Taking this into account, the antidepres-
sant activities of the synthesized compounds were also
determined by forced swimming test (FST).
Com-
pound
R
MESa)
100
30
300
b)
3a
3b
3c
3d
3e
3f
3g
3h
3i
-CH3
-C2H5
i-C3H7
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
1/3
3/3
2/3
0/3
1/3
0/3
0/3
0/3
2/3
0/3
2/3
2/3
0/3
0/3
0/3
2/3
1/3
0/3
0/3
0/3
2/3
–
–
b)
3/3
0/3
3/3
2/3
2/3
1/3
3/3
1/3
3/3
3/3
0/3
2/3
2/3
3/3
3/3
0/3
1/3
0/3
0/3
n-C4H9
n-C5H11
n-C6H13
n-C7H15
n-C8H17
n-C9H19
n-C10H21
-C6H5
Results and discussion
Synthesis
Compounds were prepared as outlined in Scheme 1.
Compounds 2a–2u were prepared by the reaction of com-
pound 1 with various phenols or aliphatic alcohol in
dimethyl sulfoxide in the presence of sodium hydroxide,
which reacted further with sodium azide to afford com-
pounds 3a–3u [16]. Structures of these compounds have
been confirmed by IR, MS, 1H-NMR, and elementary anal-
ysis.
3j
3k
3l
-C6H4(p-OCH3) 0/3
-C6H4(o-OCH3) 0/3
3m
3n
3o
3p
3q
3r
3s
3t
-C6H4(p-CH3)
-C6H4(o-CH3)
-C6H4(m-CH3)
-C6H4(p-Cl)
-C6H4(o-Cl)
-C6H4(m-Cl)
C6H3(2,4-Cl2)
-C6H4(p-F)
0/3
0/3
0/3
0/3
0/3
0/3
0/3
0/3
Pharmacological evaluations
Anticonvulsant activities of the synthesized compounds
were determined by maximal MES test according to the
phase-I tests of the anti-epileptic drug development
(ADD) program [17, 18]. These compounds were also
screened for their antidepressant activities in mice using
the FST. The forced swimming test is a behavioral test
used to predict the efficacy of antidepressant treatments
[19]. It is used effectively in predicting the activity of a
wide variety of antidepressants such as MAO inhibitors
[20] and typical antidepressants [21]. It is also has a good
predictive value for the antidepressant potency in
humans [22].
The results of the preliminary anticonvulsant activities
of 3a–3u are summarized in Table 1. As shown in Table 1,
compounds 3c, 3e, 3i, 3k, 3l, 3p, and 3q exhibited com-
pletely protection at a dose of 300 mg/kg in the MES test.
Compounds 3f, 3g, 3h, 3j, 3n, 3o, and 3s displayed weak
anticonvulsant activities. However, no compound exhib-
ited activities at a dose of 30 mg/kg. Among all the com-
pounds, 3b protected completely against MES-induced
seizure at a dose of 100 mg/kg, and is the best active com-
pound in this series.
Taking into account that interactions appear between
anticonvulsant and antidepressant drugs [11], antide-
pressant activities of the compounds were also investi-
gated with the forced swimming test (FST) and the results
revealed that the compounds prepared displayed antide-
pressant activitiy. The obtained data on antidepressant
activities of the compounds and reference drug (Fluoxe-
tine) are given in Table 2. In this study, all of the com-
pounds except 3a, 3b, 3d, 3k, 3p, and 3r significantly
reduced the duration of immobility times at 100 mg/kg
3u
a)
Maximal electroshock test (number of animals protected/
number of animals tested);
dead.
b)
compared to control (p a 0.05). Compounds 3c, 3e–3i, 3l,
and 3s significantly reduced the duration of immobility
times at 100 mg/kg dose level compared to control with p
a 0.01. Among all synthesized compounds, 5-(hexyloxy)-
tetrazolo[1,5-a]quinazoline 3f was the most promising
compound and reduced the immobility times by 66.9% at
100 mg/kg compared with Fluoxetine reducing immobil-
ity time by 52.3% at 30 mg/kg.
Analyzing the antidepressant activities of the synthe-
sized compounds 3a–3u, the following SAR was gained.
The length of the alkyl chain appears to have a direct
impact on the antidepressant activity of the 5-alkoxyl
derivatives. From compound 3a to 3j, as the alkyl-chain
length increased, immobility times gradually decreased
with compound 3f (with the n-hexyloxy substituted
group) being the most active. The trend reversed, how-
ever, when the alkyl chain had more than six carbons. In
compounds 3k–3u a substitution with phenoxyl groups
was undertaken. Among of these compounds, compound
3l (with p-OCH3 phenoxyl-substituted group) was the
most active compound, reducing the immobility time by
51.7%. Compound 3m (with o-OCH3 phenoxyl-substituted
group) is less active compared with 3l. Compared to the
derivatives with different CH3-substituted positions on
the phenyl group (3n, 3o, and 3p), their rank of activity
order was p-CH3 > o-CH3 > m-CH3.
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Arch. Pharm. Chem. Life Sci. 2009, 342, 671–675
5-Alkoxy-tetrazolo[1,5-a]quinazolines
673
Table 2. Antidepressant activities of the compounds in FST.
Experimental
Com-
pound
R
Duration of
immobility
(s)
Change from
control
(%)
Chemistry
Melting points were determined in open capillary tubes and
were uncorrected. IR spectra were recorded (in KBr) on a FT-
IR1730 (Perkin-Elmer, USA). 1H-NMR spectra were measured on
an AV-300 (Bruker, Switzerland), and all chemical shifts were
given in ppm relative to tetramethysilane. Mass spectra were
measured on an HP1100LC (Agilent Technologies, USA). Elemen-
tal analyses were performed on a 204Q CHN (Perkin Elmer).
Microanalyses of C, N, and H were performed using a Heraeus
CHN Rapid Analyzer (Heraeus, Hanau, Germany). The major
chemicals were purchased from Aldrich Chemical Corporation.
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
3o
3p
-CH3
-C2H5
i-C3H7
n-C4H9
n-C5H11
n-C6H13
n-C7H15
n-C8H17
–
–
–
–
116.3 € 17.63 **
–
–29.3
–
112.3 € 14.91 **
62.2 € 12.58 **
109.0 € 18.72 **
106.8 € 28.86 **
130.17 € 15.03 **
133.3 € 18.57 *
–
85.2 € 13.42 **
125.8 € 18.86 *
118.8 € 27.13 *
125.8 € 23.45 *
131.3 € 24.97
131.0 € 22.44 *
129.7 € 27.93
113.0 € 18.79 **
136.5 € 12.96 *
124.3 € 23.17 *
61.3 € 23.71 **
164.7 € 15.04
–31.8
–62.2
–33.8
–35.1
–21.0
–19.0
–
–51.7
–23.7
–27.8
–23.6
–20.2
–20.5
–21.3
–31.4
–17.1
–24.5
–62.8
–
n-C9H19
n-C10H21
-C6H5
General procedure for the synthesis of 5-alkoxy-
tetrazolo[1,5-a]quinazoline 3a–3u
-C6H4(p-OCH3)
-C6H4(o-OCH3)
-C6H4(p-CH3)
-C6H4(o-CH3)
-C6H4(m-CH3)
-C6H4(p-Cl)
-C6H4(o-Cl)
-C6H4(m-Cl)
C6H3(2,4-Cl2)
-C6H4(p-F)
The starting compound 2,4-dichloroquinazoline (compound 1)
(0.5 g, 2.5 mmol) and an appropriate alkanol or substituted phe-
nol (3.0 mmol) were dissolved in dimethyl sulphoxide (30 mL),
after dissolving, sodium hydroxide (0.1 g, 2.5 mmol) was added
into the mixture and reacted at 508C for about 15 h. Then NaN3
(0.25 g, 3.75 mmol) was added and the reaction mixture was
stirred at 658C for another 32 h. The mixture was cooled and
poured into ice water. The solid precipitate was filtered, washed
with excessive cold water, dried, and was crystallized from etha-
nol. The yield, the melting point, and the spectral data of the
compounds 3a–3u are given below.
3q
3r
3s
3t
3u
Fluoxetine
Control
Values represent the mean € S.E.M. (n = 6).
5-Methoxytetrazolo[1,5-a]quinazoline 3a
Compounds prepared were administered at 100 mg/kg, Fluox-
etine was administered at 30 mg/kg;
* significantly compared to control (Student’s t-test; 0.01 a p a
0.05);
** very significantly compared to control (Student’s t-test; p a
0.01); – toxicity in mice.
M.p.: 196–1988C; yield: 32%; IR (KBr) cm–1: 1618 (C = N), 1307,
1192 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.53 (d, J = 8.3 Hz, 1H,
H-9), 8.34 (d, J = 8.2 Hz, 1H, H-6), 8.03 (t, J = 8.0 Hz, 1H, H-8), 7.77 (t,
J = 7.6 Hz, 1H, H-7), 4.35 (s, 3H, -OCH3); MS m/z: 202 [M + 1]. Anal.
calcd. for C9H7N5O: C, 53.73; H, 3.51; N, 34.81. Found: C, 54.24; H,
3.59; N, 33.78.
5-Ethoxytetrazolo[1,5-a]quinazoline 3b
M.p.; 156–1588C; yield: 46%; IR (KBr) cm–1: 1618 (C = N), 1305,
1191 (C-O-C);1H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.4 Hz, 1H, H-
9), 8.34 (d, J = 8.0 Hz, 1H, H-6), 8.05 (t, J = 7.9 Hz, 1H, H-8), 7.76 (t, J
= 7.8 Hz, 1H, H-7), 4.82 (q, J = 7.1 Hz, 2H, -OCH2-), 1.59 (t, J = 7.1 Hz,
3H, -CH3); MS m/z: 216 [M + 1]. Anal. calcd. for C10H9N5O: C, 55.81;
H, 4.22; N, 32.54. Found: C, 55.93; H, 4.32; N, 32.21.
Comparisons of the halogen-substituted derivatives
indicated that different halogen atoms contributed to
the antidepressant activity differently. Compared to the
derivatives with different Cl-substituted positions on the
phenyl ring (3q, 3r, 3s, and 3t), their rank-of-activity order
was m-Cl > o-Cl L p-Cl > 2,4-Cl2. Compound 3u (with p-F-
phenoxyl-substituted group) possess activity reducing
the immobility times by 24.5%.
In conclusion, a series of 5-alkoxy-tetrazolo[1,5-a]quina-
zolines were synthesized and their anticonvulsant and
antidepressant activities were investigated. Most of them
showed weak anticonvulsant activity at a dose of 300 mg/
kg. However, most of them exhibited significant antide-
pressant activities and 5-(hexyloxy)tetrazolo[1,5-a]quina-
zoline 3f was the most promising compound decreasing
immobility time by 62.2% at 100 mg/kg dose level. Fur-
ther experiments are needed to explore the possible anti-
depressant mechanism and the work will be reported in
detail in a series of forthcoming papers.
5-Isopropoxytetrazolo[1,5-a]quinazoline 3c
M.p.: 172–1748C; yield: 36%; 1H-NMR (CDCl3, 300 MHz) d: 8.51 (d, J
= 8.4 Hz, 1H, H-9), 8.33 (d, J = 8.1 Hz, 1H, H-6), 8.04 (t, J = 7.9 Hz,
1H, H-8), 7.75 (t, J = 7.8 Hz, 1H, H-7), 5.82 (m, J = 6.2 Hz, 1H, -OCH-),
1.55 (d, J = 6.2 Hz, 6H, -(CH3)2); IR (KBr) cm–1: 1607 (C = N), 1302,
1186 (C-O-C); MS m/z: 230 [M + 1]. Anal. calcd. for C11H11N5O: C,
57.63; H, 4.84; N, 30.55. Found: C, 57.82; H, 4.88; N, 30.45.
5-Butoxytetrazolo[1,5-a]quinazoline 3d
M.p.: 100–1028C; yield: 37%; IR (KBr) cm–1: 1615 (C = N), 1302,
1190. (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.3 Hz, 1H,
H-9), 8.28 (d, J = 8.2 Hz, 1H, H-6), 8.05 (t, J = 7.9 Hz, 1H, H-8), 7.76 (t,
J = 7.7 Hz, 1H, H-7), 4.76 (t, J = 6.6 Hz, 2H, -OCH2-), 1.95 (m, J = 7.1
Hz, 2H, -CH2-), 1.59 (m, J = 7.4 Hz, 2H, -CH2-), 1.04 (t, J = 7.4 Hz, 3H,
-CH3); MS m/z: 244 [M + 1]. Anal. calcd. for C12H13N5O: C, 59.25; H,
5.39; N, 28.79. Found: C, 59.27; H, 5.36; N, 28.34.
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H.-J. Wang et al.
Arch. Pharm. Chem. Life Sci. 2009, 342, 671–675
5-(Pentyloxy)tetrazolo[1,5-a]quinazoline 3e
5-(4-Methoxyphenoxy)tetrazolo[1,5-a]quinazoline 3l
M.p.: 198–2008C; yield: 65%; IR (KBr) cm–1: 1618 (C = N), 1307,
1194 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.7 Hz, 1H,
H-9), 8.49 (d, J = 9.8 Hz, 1H, H-6), 8.06 (t, J = 7.9 Hz, 1H, H-8), 7.87 (t,
J = 7.8 Hz, 1H, H-7), 7.17 (d, J = 9.2 Hz, 2H, Ar-H), 6.94 (d, J = 9.2 Hz,
2H, Ar-H), 3.80 (s, 3H, -OCH3); MS m/z: 294 [M + 1]. Anal. calcd. for
C15H11N5O2: C, 61.43; H, 3.78; N, 23.88. Found: C, 61.46; H, 3.74;
N, 23.82.
M.p. 112–1148C; yield: 51%; IR (KBr) cm–1: 1609 (C = N), 1307,
1194 (C-O-C);1H-NMR (CDCl3, 300 MHz) d: 8.51 (d, J = 8.3 Hz, 1H, H-
9), 8.33 (d, J = 8.0 Hz, 1H, H-6), 8.04 (t, J = 7.8 Hz, 1H, H-8), 7.76 (t,
J = 7.7 Hz, 1H, H-7), 4.74 (t, J = 6.7 Hz, 2H, -OCH2-), 1.97 (m, 2H,
-CH2-), 1.43–1.54 (m, 4H, -CH2CH2-), 0.97 (t, J = 7.0 Hz, 3H, -CH3); MS
m/z: 258 [M + 1]. Anal. calcd. for C13H15N5O: C, 60.69; H, 5.88; N,
27.22. Found: C, 60.73; H, 5.90; N, 27.16.
5-(Hexyloxy)tetrazolo[1,5-a]quinazoline 3f
5-(2-Methoxyphenoxy)tetrazolo[1,5-a]quinazoline 3m
M.p.: 220–2228C; yield: 60%; IR (KBr) cm–1: 1604 (C = N), 1307,
1195 (C-O-C);1H-NMR (CDCl3, 300 MHz) d: 8.59 (d, J = 8.4 Hz, 2H, H-
6, H-9), 8.13 (t, J = 7.9 Hz, 1H, H-8), 7.85 (t, J = 7.8 Hz, 1H, H-7),
7.04–7.36 (m, 4H, Ar-H), 3.75 (s, 3H, -OCH3); MS m/z: 294 [M + 1].
Anal. calcd. for C15H11N5O2: C, 61.43; H, 3.78; N, 23.88. Found: C,
61.45; H, 3.74; N, 23.83.
M.p.: 106–1088C; yield: 54%; IR (KBr) cm–1: 1604 (C = N), 1300,
1192 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.2 Hz, 1H,
H-9), 8.34 (d, J = 8.2 Hz, 1H, H-6), 8.05 (t, J = 7.8 Hz, 1H, H-8), 7.76 (t,
J = 7.8 Hz, 1H, H-7), 4.75 (t, J = 6.7 Hz, 2H, -OCH2-), 1.96 (m, 2H,
-CH2-), 1.38–1.58 (m, 6H, -(CH2)3-), 0.93 (t, J = 7.0 Hz, 3H, -CH3); MS
m/z: 272 [M + 1]. Anal. calcd. for C14H17N5O: C, 61.98; H, 6.32; N,
25.81. Found: C, 62.21; H, 6.36; N, 25.57.
5-(Heptyloxy)tetrazolo[1,5-a]quinazoline 3g
5-(p-Tolyloxy)tetrazolo[1,5-a]quinazoline 3n
M.p.: 110–1128C; yield: 30%; IR (KBr) cm–1: 1602 (C = N), 1305,
1194 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.3 Hz, 1H,
H-9), 8.33 (d, J = 8.2 Hz, 1H, H-6), 8.05 (t, J = 7.8 Hz, 1H, H-8), 7.76 (t,
J = 7.8 Hz, 1H, H-7), 4.75 (t, J = 6.7 Hz, 2H, -OCH2-), 1.96 (m, 2H,
-CH2-), 1.33–1.59 (m, 8H, -(CH2)4-), 0.91 (t, J = 6.5 Hz, 3H, -CH3); MS
m/z: 286 [M + 1]. Anal. calcd. for C15H19N5O: C, 63.14; H, 6.71; N,
24.54. Found: C, 63.17; H, 6.72; N, 24.50.
M.p.: 202–2048C; yield: 63%; IR (KBr) cm–1: 1602 (C = N), 1307,
1203 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.59 (d, J = 8.4 Hz, 1H,
H-9), 8.58 (d, J = 8.3 Hz, 1H, H-6), 8.14 (t, J = 7.9 Hz, 1H, H-8), 7.86 (t,
J = 7.7 Hz, 1H, H-7), 7.19–7.32 (m, 4H, Ar-H), 2.44 (s, 3H, -CH3); MS
m/z: 278 [M + 1]. Anal. calcd. for C15H11N5O: C, 64.97; H, 4.00; N,
25.26. Found: C, 64.99; H, 4.01; N, 25.23.
5-(o-Tolyloxy)tetrazolo[1,5-a]quinazoline 3o
5-(Octyloxy)tetrazolo[1,5-a]quinazoline 3h
M.p.: 177–1798C; yield: 54%; IR (KBr) cm–1: 1605 (C = N), 1307,
1201 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.54 (d, J = 7.4 Hz, 1H,
H-9), 8.52 (d, J = 7.0 Hz, 1H, H-6), 8.08 (t, J = 7.9 Hz, 1H, H-8), 7.80 (t,
J = 7.7 Hz, 1H, H-7), 7.16–7.27 (m, 4H, Ar-H), 2.16 (s, 3H, -CH3); MS
m/z: 278 [M + 1]. Anal. calcd. for C15H11N5O: C, 64.97; H, 4.00; N,
25.26. Found: C, 64.98; H, 4.02; N, 25.25.
M.p.: 96–988C; yield: 59%; IR (KBr) cm–1: 1605 (C = N), 1307, 1192
1
(C-O-C); H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.3 Hz, 1H, H-9),
8.34 (d, J = 8.2 Hz, 1H, H-6), 8.05 (t, J = 7.9 Hz, 1H, H-8), 7.76 (t, J =
7.7 Hz, 1H, H-7), 4.74 (t, J = 6.6 Hz, 2H, -OCH2-), 1.96 (m, 2H, -CH2-),
1.31–1.59 (m, 10H, -(CH2)5-), 0.88 (t, J = 6.6 Hz, 3H, -CH3); MS m/z:
300 [M + 1]. Anal. calcd. for C16H21N5O: C, 64.19; H, 7.07; N, 23.39.
Found: C, 64.11; H, 7.06; N, 23.43.
5-(m-Tolyloxy)tetrazolo[1,5-a]quinazoline 3p
M.p.: 171–1738C; yield: 44%; IR (KBr) cm–1: 1604 (C = N), 1307,
1197 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.59 (d, J = 8.4 Hz, 1H,
H-9), 8.58 (d, J = 8.5 Hz, 1H, H-6), 8.14 (t, J = 7.9 Hz, 1H, H-8), 7.86 (t,
J = 7.7 Hz, 1H, H-7), 7.11–7.41 (m, 4H, Ar-H), 2.44 (s, 3H, -CH3); MS
m/z: 278 [M + 1]. Anal. calcd. for C15H11N5O: C, 64.97; H, 4.00; N,
25.26. Found: C, 64.98; H, 4.01; N, 25.24.
5-(Nonyloxy)tetrazolo[1,5-a]quinazoline 3i
M.p.: 80–828C; yield: 57%; IR (KBr) cm–1: 1606 (C = N), 1306, 1194
1
(C-O-C); H-NMR (CDCl3, 300 MHz) d: 8.45 (d, J = 8.3 Hz, 1H, H-9),
8.24 (d, J = 7.9 Hz, 1H, H-6), 7.98 (t, J = 7.8 Hz, 1H, H-8), 7.69 (t, J =
7.7 Hz, 1H, H-7), 4.68 (t, J = 5.9 Hz, 2H, -OCH2-), 0.74–1.89 (m, 17H,
-(CH2)7CH3); MS m/z: 314 [M + 1]. Anal. calcd. for C17H23N5O: C,
65.15; H, 7.40; N, 22.35. Found: C, 65.18; H, 7.43; N, 22.27.
5-(4-Chlorophenoxy)tetrazolo[1,5-a]quinazoline 3q
M.p.: 190–1928C; yield: 51%; IR (KBr) cm–1: 1606 (C = N), 1307,
1209 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.56 (d, J = 8.3 Hz, 1H,
H-9), 8.55 (d, J = 8.1 Hz, 1H, H-6), 8.16 (t, J = 7.9 Hz, 1H, H-8), 7.87 (t,
J = 7.8 Hz, 1H, H-7), 7.49 (d, J = 8.9 Hz, 2H, Ar-H), 7.30 (d, J = 8.9 Hz,
2H, Ar-H); MS m/z: 298.5 [M + 1], 300.5 [M + 1]. Anal. calcd. for
C14H8ClN5O: C, 56.48; H, 2.71; N, 23.52. Found: C, 56.51; H, 2.72;
N, 23.51.
5-(Decyloxy)tetrazolo[1,5-a]quinazoline 3j
M.p.: 102–1048C; yield: 47%; IR (KBr) cm–1: 1605 (C = N), 1303,
1192 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.52 (d, J = 8.4 Hz, 1H,
H-9), 8.33 (d, J = 8.3 Hz, 1H, H-6), 8.05 (t, J = 7.4 Hz, 1H, H-8), 7.76 (t,
J = 8.0 Hz, 1H, H-7), 4.75 (t, J = 6.6 Hz, 2H, -OCH2-), 1.96 (m, 2H,
-CH2-), 1.28–1.58 (m, 14H, -(CH2)7-), 0.87 (t, J = 6.4 Hz, 3H, -CH3); MS
m/z: 328 [M + 1]. Anal. calcd. for C18H25N5O: C, 66.03; H, 7.70; N,
21.39. Found: C, 66.17; H, 7.72; N, 21.45.
5-Phenoxytetrazolo[1,5-a]quinazoline 3k
5-(2-Chlorophenoxy)tetrazolo[1,5-a]quinazoline 3r
M.p.: 212–2148C; yield: 48%; IR (KBr) cm–1: 1604 (C = N), 1307,
1201 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.62 (d, J = 8.3 Hz, 2H,
H-6, H-9), 8.16 (t, J = 7.7 Hz, 1H, H-8), 7.89 (t, J = 7.7 Hz, 1H, H-7),
7.32–7.57 (m, 4H, Ar-H); MS m/z: 298.5 [M + 1], 300.5 [M + 1]. Anal.
calcd. for C14H8ClN5O: C, 56.48; H, 2.71; N, 23.52. Found: C, 56.50;
H, 2.72; N, 23.49.
M.p.: 153–1558C; yield: 44%; IR (KBr) cm–1: 1606 (C = N), 1307,
1198 (C-O-C);1H-NMR (CDCl3, 300 MHz) d: 8.60 (d, J = 8.4 Hz, 1H, H-
9), 8.58 (d, J = 8.6 Hz, 1H, H-6), 8.14 (t, J = 7.9 Hz, 1H, H-8), 7.87 (t, J
= 7.8 Hz, 1H, H-7), 7.32–7.55 (m, 5H, Ar-H); MS m/z: 264 [M + 1].
Anal. calcd. for C14H9N5O: C, 63.87; H, 3.45; N, 26.60. Found: C,
63.90; H, 3.44; N, 26.59.
i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

Arch. Pharm. Chem. Life Sci. 2009, 342, 671–675
5-Alkoxy-tetrazolo[1,5-a]quinazolines
675
This work was supported by the National Natural Science Foundation
of China (Nos. 30860340 and 30760290) and Important Item Founda-
tion of Ministry of Education P.R. China (No. 2007024).
5-(3-Chlorophenoxy)tetrazolo[1,5-a]quinazoline 3s
M.p.: 222–2248C; yield: 46%; IR (KBr) cm–1: 1606 (C = N), 1307,
1206 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.61 (d, J = 8.4 Hz, 1H,
H-9), 8.54 (d, J = 8.1 Hz, 1H, H-6), 8.16 (t, J = 7.8 Hz, 1H, H-8), 7.88 (t,
J = 7.6 Hz, 1H, H-7), 7.24–7.48 (m, 4H, Ar-H); MS m/z: 298.5 [M + 1],
300.5 [M + 1]. Anal. calcd. for C14H8ClN5O: C, 56.48; H, 2.71; N,
23.52. Found: C, 56.51; H, 2.73; N, 23.48.
The authors have declared no conflict of interest.
References
5-(2,4-Dichlorophenoxy)tetrazolo[1,5-a]quinazoline 3t
M.p.: 226–2278C; yield: 42%; IR (KBr) cm–1: 1604 (C = N), 1307,
1196 (C-O-C); 1H-NMR (CDCl3, 300 MHz) d: 8.63 (d, J = 8.6 Hz, 1H,
H-9), 8.58 (d, J = 8.7 Hz, 1H, H-6), 8.18 (t, J = 7.8 Hz, 1H, H-8), 7.91 (t,
J = 7.7 Hz, 1H, H-7), 7.58 (d, J = 2.1 Hz, 1H, Ar-H), 7.36 (q, J = 2.1 Hz,
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C14H7Cl2N5O: C, 50.63; H, 2.12; N, 21.09. Found: C, 50.66; H, 2.12;
N, 21.05.
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i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com