Efficient synthesis of arylaminotetrazoles in water

Article abstract of DOI:10.1016/j.tet.2010.03.003

Arylaminotetrazole derivatives are synthesized efficiently by the reaction of arylcyanamides and sodium azide in the presence of ZnCl₂ under aqueous conditions at reflux. Generally, isomer of 5-arylamino-1H-tetrazole can be obtained from arylcy

Full text of DOI:10.1016/j.tet.2010.03.003

Tetrahedron 66 (2010) 3866–3870
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Efficient synthesis of arylaminotetrazoles in water
a
a
,
a
b
*
Davood Habibi , Mahmoud Nasrollahzadeh , Ali Reza Faraji , Yadollah Bayat
a
Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 6517838683, Iran
Department of Chemistry, Malek-Ashtar University of Technology, Tehran, Iran
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 July 2009
Received in revised form 10 February 2010
Accepted 1 March 2010
Available online 12 March 2010
Arylaminotetrazole derivatives are synthesized efficiently by the reaction of arylcyanamides and sodium
azide in the presence of ZnCl under aqueous conditions at reflux. Generally, isomer of 5-arylamino-
H-tetrazole can be obtained from arylcyanamides carrying electron-withdrawing substituent on aryl
ring and as the electropositivity of substituent is increased, the product is shifted toward the isomer of
-aryl-5-amino-1H-tetrazole.
2
1
1
Ó 2010 Published by Elsevier Ltd.
Keywords:
ZnCl
2
5
1
-Arylamino-1H-tetrazole
-Aryl-5-amino-1H-tetrazole
Arylcyanamide
Sodium azide
1. Introduction
tetrazoles, 5-aryl/alkyl oxytetrazoles, and 5-aryl/alkyl amino-
3
,4,20,27–29a,29b
tetrazoles, respectively.
In most of them, the reaction
5
-Substituted tetrazoles (RCN
4
H) may serve as a non-classical
H) in biologically
actually proceeds in solutions of hydrazoic acid in solvents such as
benzene, toluene, xylene, and chloroform. Herbst and Garbrecht
have shown that cyanamides may be converted to aminotetrazoles
using hydrazoic acid, which often result in a mixture of isomers
isostere for the carboxylic acid moiety (RCO
2
active molecules.1 Hansch has shown that anionic tetrazoles are
almost 10 times more lipophilic than corresponding carboxylates,
which is an important factor to bear in mind when designing a drug
molecule to pass through cell membranes.8 There is considerable
–7
2
2b
(Scheme 1).
4
,6
interest in the medicinal and biological applications of tetrazoles,
including 5-aminotetrazoles, due to their reported anti-allergic and
anti-asthmatic,
NH
9,10
11
N
antiviral and anti-inflammatory,
anti-neo-
NH
C
12
13
4–16
N
plastic, and cognition disorder activities. Tetrazoles are also
A'
R
1
R
R
applied as ligands in coordination chemistry,
as explosives and
N
N
H
rocket propellants.1
7–19
Another important application of tetrazoles
N
H
N3
A
is the preparation of imidoylazides.20
HN3
The earliest published methods for the preparation of amino-
tetrazole derivatives were reactions including the following: (1)
HN
C
N
NH2
R
N
NH2
B'
21
addition of NaNO
2
to aminoguanidine (2) addition of NaN
3
to
R
C
N
carbodiimides2 or cyanamides (3) reactions of amines with
1c
22
2
3
N
a leaving group in the tetrazoles 5-position (4) nucleophilic
substitution by N
b) sulfur from thioureas in the presence of mercury
salts.
N
N3
ꢀ
24
3
of (a) chlorine in
a
-chloroformamidines and
N
B
2
5,26
(
or lead
21a
Scheme 1.
The addition of the azide anion to nitriles, cyanates, and cyan-
amides is the most common route for preparing 5-substituted
Previously, the 5-monosubstitutedamino-1H-tetrazoles were
synthesized by thermal isomerization of 1-substituted-5-amino-
H-tetrazoles in boiling ethylene glycol or in melt state (180–
1
*
Corresponding author. Tel.: þ98 811 8282807; fax: þ98 811 8257407; e-mail
ꢁ
21a,30
address: mahmoudnasr81@gmail.com (M. Nasrollahzadeh).
200 C).
Later, Congreve has reported a two-step synthesis of
0
040-4020/$ – see front matter Ó 2010 Published by Elsevier Ltd.
doi:10.1016/j.tet.2010.03.003

D. Habibi et al. / Tetrahedron 66 (2010) 3866–3870
Table 1 (continued )
3867
1
-aryl-5-amino-1H-tetrazoles from the corresponding 1-arylte-
31
trazoles via cyanamide intermediates. The reaction suffers from
some drawbacks such as harsh reaction conditions, low tempera-
Yielda
%
Entry
Substrate
Product
NH2
ꢁ
tures (ꢀ70 C), use of large excess of sodium azide and organo-
CN
NH
Cl
N
6
Cl
85
84
86
89
lithium reagents that are potentially dangerous. Vorobiov and
co-workers published a three-step synthesis of 1-aryl-5-amino-
N
N 3f
1
f
N
1
H-tetrazoles, which proceeded in low yields from the corre-
NH2
sponding aromatic amines via isolation of intermediate cyana-
mides.32 Unfortunately, this approach is not well developed due to
the insufficient stability of the intermediate cyanamides. In most
cases, N-arylureas and other by-products were mostly formed and
the intermediate cyanamides were not stable enough to be isolated.
Therefore, the 1-aryl-5-amino-1H-tetrazoles were produced in low
yields. The above mentioned syntheses require the use of highly
toxic and explosive hydrazoic acid. On the other hand, in most cases
only the 1-aryl-5-amino-1H-tetrazoles or mixture of isomers
5-arylamino-1H-tetrazole and 1-aryl-5-amino-1H-tetrazoles) was
obtained.
Due to safety considerations, we required a method that did
not use of hydrazoic acid or an azide source that produced
hydrazoic acid in situ because of the associated hazards. If
hydrazoic acid is used, care must be taken by monitoring the
CN
NH
1g
H3C
N
7
8
9
H3C
N
N 3g
N
CH3
CH3
NH2
CN
NH
1h
3
H C
N
H3C
N
N 3h
N
CH3
CH3
HN
NH2
(
CN
NH
1i
N
N
N 3i
N
CN
NH2
concentration of hydrazoic acid in the reaction mixture to avoid an
10
83
explosion.3
,4,17,29
N
A substitute for hydrazoic acid is a mixture of
sodium azide and ammonium chloride, with dimethylformamide
N
N
3
j
1j
as the solvent.1
7,27c
N
In dimethylformamide, the reaction mixture
a
ꢁ
Yields refer to pure isolated products.
must be heated to 150 C for several hours to several days. An
additional disadvantage of dimethylformamide is its solubility in
both organic solvents and water. Thus, removing DMF from
tetrazole is difficult. Therefore, it is desirable to develop a more
efficient and convenient method for the regiospecific synthesis of
arylaminotetrazoles.
In continuation of our recent work on the synthesis of hetero-
cycles,33 we herein report the synthesis of arylaminotetrazoles 3a–j
from a wide variety of arylcyanamides 1a–j with sodium azide 2
under thermal conditions in H
Scheme 2).
2 2
O using ZnCl (Table 1 and
Scheme 2.
2. Result and discussion
The cyanamides 1a–j were prepared according to literature.34 In
Table 1
order to include a reasonable range of electrical and steric effects,
the arylsubstituted cyanamides 1a–j studied included various
groups in ortho, meta, and para positions, Table 1. Several aromatic
cyanamides carrying either electron-donating or electron-
withdrawing substituents reacted and gave the products in good
yields (Table 1).
Synthesis of arylaminotetrazoles 3a–j in the presence of ZnCl
sodium azide 2 and arylcyanamides 1 under reflux conditions
2
by reaction between
Yielda
%
Entry
1
Substrate
Product
N
CN
NH
H
N
NH
O N
2
O
2
N
80
1a
N
N
3a
The following important results can be extracted from the data
collected in Table 1:
Cl
Cl
Cl
1. In this work, we have observed that the process was com-
N
CN
H
N
NH
3b
pletely regiospecific, Table 1. This is in contrast with the report that
was presented for the synthesis of aminotetrazoles using hydrazoic
2
3
88
84
NH
1b
N
N
2
2b
acid, which often results in mixture of regio isomers A and B.
. Perhaps the most remarkable feature of the reaction of the
monosubstituted cyanamides with hydrazoic acid is the unidirec-
Cl
2
N
CN
NH
1c
H
N
NH
3
,4,21a,22b,27,30,35
tional character of the cyclization step.
The sub-
N
N
N
3c
Cl
Cl
stituent identity appears to play at best a minor role in directing the
course of the reaction. Substituents as different in their electrical
effects as the methyl group and the p-nitrophenyl group permit the
formation of the same type of compound, presumably through the
intermediate formation of a guanyl azide. Surprisingly, ring-closure
of the substituted guanyl azide in all of these methods yields the
CN
NH
H
N
NH
4
5
61
90
N
1
d
N
3d
NH2
CN
NH
Br
N
1-alkyl- or 1-aryl-5-aminotetrazole as major products (as much as
Br
N
N 3e
95% in certain cases). No serious consideration appears to have
been given by previous workers to the isolation or detection of the
1
e
N

3868
D. Habibi et al. / Tetrahedron 66 (2010) 3866–3870
other regio isomer, although Stolle and Heintz reported the iso-
lation of 5-anilinotetrazole in very small yield from the reaction of
phenylthiourea with lead oxide and sodium azide.
In contrast with the reports that have previously been pub-
lished, in our methods, a clear distinction is that tetrazoles 3 are
affected by the substituents in arylcyanamides 1a–j, and isomer A
or B is obtained, Table 1. In other words, there is an excellent
correlation exclusively between the effect of substitution on the
benzene ring and the major product. Generally, when the sub-
stitution on the aryl ring is electron-donating in arylcyanamides
tetrazole (A) generally show a wide separation in the chemical
shifts of the ortho-, meta-, and para-aryl protons, while 1-aryl-5-
amino-1H-tetrazoles isomers (B) had a narrow separation of the
aryl ring protons (Figs. 1 and 2). On the other hand, 5-arylamino-
1H-tetrazoles isomers (A) contain two NH bonds (NH of the amine
3
6
A
T
attached to the aryl group (NH ) and NH of the tetrazole ring (NH ))
and 1-aryl-5-amino-1H-tetrazoles isomers (B) contain a NH bond.
2
T
The free N–H bond of tetrazoles (NH ) makes them acidic mole-
cules, and not surprisingly it has been shown that both the aliphatic
a
and aromatic heterocycles have pK values that are similar to the
1
a–j, the formation of 1-aryl-5-amino-1H-tetrazoles (B) is favored
corresponding carboxylic acids, due to the ability of the moiety to
0
6,38
via guanidine azide intermediate B (Table 1 and entries 6–9) and as
the electronegativity of substituent is increased, the product is
shifted toward the 5-arylamino-1H-tetrazole (A) (Table 1 and en-
tries 1,2). In other words, if cyclization were to involve the nitrogen
stabilize a negative charge by electron delocalization.
In general,
tetrazolic acids exhibit physical characteristics similar to carboxylic
T
acids. Thus, signal of the NH proton of the tetrazole ring (NH )
1
1
shifted downfield (see Fig. 1 and H NMR data of 3a–d). Indeed, H
0
A
carrying the aryl substituent in guanidine azide intermediate B ,
NMR spectra showed signals at
d
¼9–10 ppm indicative of NH in 5-
1
1
-aryl-5-amino-1H-tetrazoles (B) would result. On the other hand,
arylamino-1H-tetrazoles isomers (A) (Fig. 1), whereas H NMR
spectra of 1-aryl-5-amino-1H-tetrazoles isomers (B) showed one
involvement of the terminal unsubstituted nitrogen in the cycli-
zation would result in 5-arylamino-1H-tetrazoles (A) via guanidine
azide intermediate A . This is similar to the substituent effect on the
peak at
2
d¼6.6–7 ppm indicative of the NH group (Figs. 2 and 3).
0
aryl ring of mechanism that was presented by Henry and co-
3
0
workers for thermal isomerization.
. It is interesting to note that in the reaction between sodium
3
azide with secondary arylcyanamides in the presence of zinc(II)
chloride in water at reflux, the results obtained from the entries 5
and 6 are not as same as the results in entries 1–3. This observation
is due to the presence of halogen groups (–Cl and –Br) on the
benzene ring in the 4-position which exerts a para orienting in-
fluence. So, the resonance effects of the p-Cl and p-Br groups cause
the nitrogen atom carrying the aryl substituent to become more
negative and the formation of 1-aryl-5-amino-1H-tetrazoles iso-
mer (B) is favored.
A comparison of 3b (chlorine atom at ortho position) with 3f
(
chlorine atom at para position) indicates that the intramolecular
hydrogen bonding in 3b favored the formation of 5-arylamino-
H-tetrazole isomer (A) (Scheme 3). As shown in Scheme 3, in the
1
conformer A
2
both the tetrazole ring and aryl fragment are
coplanar.
Figure 1. 1H NMR spectrum (500 MHz, DMSO-d
razole (3b).
6
) 5-(2-chlorophenyl)amino-1H-tet-
Scheme 3.
In all cases, the products were characterized by 1H NMR, 13
C
NMR, IR, FTIR, elemental analysis (CHN), and melting points. The
disappearance of one strong and sharp absorption band (CN
stretching band), and the appearance of an NH stretching band in
the IR spectra, provided clear evidence for the formation of aryla-
minotetrazoles. 13C NMR spectra displayed signals at
d
¼154–
37
1
157.5 ppm indicative of C5 in the tetrazole ring. On the basis of H
NMR spectra we have considered two possible structures A and B. A
comparison of 1H NMR spectra revealed that 5-arylamino-1H-
Figure 2.
1
6
H NMR spectrum (500 MHz, DMSO-d ) 1-(4-cholorophenyl)-5-amino-1H-
tetrazole (3f).

D. Habibi et al. / Tetrahedron 66 (2010) 3866–3870
3869
4.3. Typical procedure for preparation of arylaminotetrazoles 3
To a 50 mL round-bottomed flask, the cyanamide 1 (2 mmol),
sodium azide 2 (3 mmol), zinc(II) chloride (3 mmol) and of water
16 mL) were added. The reaction mixture was stirred at reflux for
5 h. After consumption of cyanamide 1, the mixture was cooled to
(
1
room temperature, the solid residue was filtered from the reaction
mixture and then was washed with water. In continuation of work-
up, the solid residue was treated with 3 N HCl (4 mL), the desired
1
13
pure products were then filtered and characterized by H NMR,
C
NMR, IR, FTIR, elemental analysis (CHN), and melting points. This
method did not require any further purification. No side product
was observed under the reaction conditions.
The spectral data of ten representative arylaminotetrazoles are
given below:
4
.3.1. 5-(4-Nitrophenyl)amino-1H-tetrazole (3a, Table 1, entry 1). Mp
ꢁ
1
218–220 C; H NMR (DMSO-d
6
, 500 MHz):
d
¼7.76 (d, J¼7.3 Hz,
13
2
1
H), 8.21 (d, J¼7.3 Hz, 2H), 10.96 (s, br, 1H); C NMR (DMSO-d
25 MHz):
¼116.8, 124.9, 140.4, 147.2, 155.2; IR (KBr) 3550, 3235,
3100, 1635, 1572, 1488, 1337, 1290, 1257, 1111, 1052, 839, 745 cm
Anal. Calcd for C : C, 40.78; H, 2.93; N, 40.77. Found: C,
6
,
d
Figure 3. 1H NMR spectrum (500 MHz, DMSO-d
razole (3e).
ꢀ1
;
6
) 5-(4-bromophenyl)amino-1H-tet-
7 6 6 2
H N O
4
0.90; H, 3.03; N, 40.64.
3
. Conclusions
In conclusion, we have reported an effective methodology for
4.3.2. 5-(2-Chlorophenyl)amino-1H-tetrazole(3b, Table 1, entry2). Mp
ꢁ
1
228–230 C; H NMR (DMSO-d
6
, 500 MHz):
d
¼7.04 (t, J¼7.7 Hz, 1H,),
the preparation of substituted arylaminotetrazoles. The significant
advantages of this methodology are high yields, simple method-
ology, a simple work-up procedure and no chromatographic sepa-
ration or crystallization is necessary to get obtain pure compounds.
The use of water as the solvent suggests good prospects for the
applicability of this process.
7
.33 (t, J¼8.4 Hz, 1H), 7.46 (d, J¼7.9 Hz 1H), 8.00 (d, J¼8.2 Hz, 1H),
13
9
1
3
6
.12 (s,1H), 14.86 (s, br, 1H); C NMR (DMSO-d
22.6, 123.5, 127.9, 129.6, 136.7, 154.8; IR (KBr) 3260, 3210, 3140,
100, 1626, 1573, 1551, 1470, 1440, 1286, 1233, 1134, 1052, 796, 742,
6
, 125 MHz):
d¼120.2,
ꢀ1
7 6 5
74, 633 cm ; Anal. Calcd for C H N Cl: C, 42.98; H, 3.09; N, 35.80.
Found: C, 43.10; H, 3.19; N, 35.68.
4
.3.3. 5-(2,5-Dichlorophenyl)amino-1H-tetrazole (3c, Table 1, en-
ꢁ
1
4
4
. Experimental
try 3). Mp 272–274 C; H NMR (DMSO-d , 500 MHz):
d
¼7.06
6
(
d, J¼8.5 Hz, 1H), 7.48 (d, J¼8.6 Hz, 1H), 8.19 (s, 1H), 9.38 (s, 1H),
13
.1. General
14.72 (s, br, 1H); C NMR (DMSO-d , 125 MHz):
d
¼118.7, 120.3,
22.5, 130.8, 132.3, 137.8, 154.4; IR (KBr) 3245, 3184, 3156, 3115,
1620, 1592, 1569, 1544, 1467, 1411, 1090, 1054, 1038, 836, 799, 772,
6
1
All reagents were purchased from Merck and Aldrich and used
without further purification. Products were characterized by spec-
ꢀ
1
664, 563, 538 cm ; Anal. Calcd for C H N Cl : C, 36.52; H, 2.17; N,
7 5 5 2
1
13
troscopy data (IR, FTIR, H NMR, and C NMR spectra), elemental
analysis (CHN) and melting points. The NMR spectra were recorded
30.43. Found: C, 36.66; H, 2.22; N, 30.56.
1
in DMSO. H NMR spectra were recorded on a Bruker Avance DRX
00 and 500 MHz instruments. The chemical shifts (
4.3.4. 5-Phenylamino-1H-tetrazole (3d, Table 1, entry 4). Mp 215–
ꢁ
10
ꢁ
1
3
d) are reported
217 C (lit. 211–212 C); H NMR (DMSO-d , 500 MHz):
d
¼6.93
6
in parts per million relative to the TMS as internal standard. J values
are given in Hertz. 13C NMR spectra were recorded at 125 and 75 Hz.
IR (KBr) and FTIR (KBr) spectra were recorded on a Shimadzu 470
and Perkin-Elmer 781 spectrophotometer, respectively. Melting
points were taken in open capillary tubes with a BUCHI 510 melting
point apparatus and were uncorrected. The elemental analysis was
performed using Heraeus CHN-O-Rapid analyzer. TLC was per-
formed on silica gel polygram SIL G/UV 254 plates.
(t, J¼7.3 Hz, 1H), 7.29 (t, J¼7.9 Hz, 2H), 7.49 (d, J¼8.2 Hz, 2H), 9.74
13
(s, 1H), 15.33 (s, br, 1H); C NMR (DMSO-d , 125 MHz):
6
d
¼116.7,
121.0, 128.9, 140.3, 155.8; IR (KBr) 3325, 3220, 1620, 1580, 1533,
1498, 1243, 1053, 785, 742, 735, 688, 660 cm
ꢀ1
.
4.3.5. 1-(4-Bromophenyl)-5-amino-1H-tetrazole (3e, Table 1, en-
ꢁ
1
try 6). Mp 239–240 C; H NMR (DMSO-d , 500 MHz):
6
d
¼6.97 (s,
2H), 7.54 (d, J¼8.1 Hz, 2H), 7.78 (d, J¼8.1 Hz, 2H); C NMR (DMSO-
, 125 MHz):
¼123.0, 126.7, 132.9, 133.4, 155.4; IR (KBr) 3340,
140, 1647, 1588, 1570, 1489, 1449, 1400, 1319, 1139, 1104, 1096,
13
d
6
d
3
ꢀ1
4
.2. Preparation of the arylcyanamides
1065, 1004, 833, 815, 516 cm ; Anal. Calcd for C
7 6 5
H N Br: C, 35.02;
H, 2.52; N, 29.17. Found: C, 35.08; H, 2.60; N, 29.21.
The cyanamides 1a–j were prepared according to literature.34
4
.3.6. 1-(4-Chlorophenyl)-5-amino-1H-tetrazole (3f, Table 1, en-
ꢁ
30a
ꢁ
6
215–217 C); H NMR (DMSO-d ,
1
4
3
.2.1. 1-Naphthylcyanamide (1j, Table 1). 1
00 MHz):
H
NMR (DMSO-d
6
,
,
try 5). Mp 217–219 C (lit.
500 MHz):
¼6.94 (s, 2H), 7.62 (d, J¼8.6 Hz, 2H), 7.68 (d, J¼8.6 Hz,
2H); C NMR (DMSO-d , 125 MHz):
¼126.9, 130.6, 133.2, 134.6,
155.8; FTIR (KBr) 3345, 3141, 1651, 1593, 1577, 1499, 1450, 1410,
d
¼7.21 (d, J¼7.4 Hz, 1H), 7.47 (t, J¼7.8 Hz, 1H), 7.54–7.59
d
1
3
13
(
7
1
1
7
m, 3H), 7.89–7.93 (m, 1H), 8.09–8.12 (m, 1H); C NMR (DMSO-d
5 MHz):
21.7, 114.3, 111.5; FTIR (KBr): v 3382, 3165, 3079, 2961, 2897, 2226,
613, 1515, 1436, 1409, 1302, 1256, 1181, 1108, 1016, 859, 835, 811,
6
6
d
d
¼136.4, 134.4, 128.7, 127.0, 126.6, 126.3, 124.1, 122.8,
ꢀ
1
1324, 1144, 1095, 1074, 1010, 838, 819, 734, 630, 557, 513, 471 cm
.
ꢀ
1
8 2
71 cm ; Anal. Calcd for C11H N : C, 78.55; H, 4.79; N, 16.65.
4.3.7. 1-(4-Methylphenyl)-5-amino-1H-tetrazole (3g, Table 1, en-
try 7). Mp 178–179 C (lit.
ꢁ
30a
ꢁ
1
Found: C, 78.66; H, 4.90; N, 16.53.
175.5–177 C); H NMR (DMSO-d ,
6

3870
D. Habibi et al. / Tetrahedron 66 (2010) 3866–3870
5
(
1
00 MHz):
d, J¼8.3 Hz, 2H); C NMR (DMSO-d
31.8, 139.8, 155.8; FTIR (KBr) 3306, 3141, 1655, 1594, 1572, 1519,
d
¼2.38 (s, 3H), 6.80 (s, 2H), 7.39 (d, J¼7.8 Hz, 2H), 7.43
10. Peet, N. P.; Baugh, L. E.; Sundler, S.; Lewis, J. E.; Matthews, E. H.; Olberding, E. L.;
Shah, D. N. J. Med. Chem. 1986, 29, 2403.
1. Girijavallabhan, V.M.; Pinto, P.A.; Genguly, A.K.; Versace, R.W. Eur. Patent EP
74,867, 1988; Chem. Abstr. 1989,110 23890.
12. (a) Akimoto, H.; Ootsu, K.; Itoh, F. Eur. Patent EP 530,537, 1993; Chem. Abstr.
993,119 226417. (b) Taveras, A.G.; Mallams, A.K.; Afonso, A. Int. Patent WO
,811,093, 1998; Chem. Abstr. 1998, 128, 230253.
3. Mitch, C.H.; Quimby, S.J. Int. Patent WO 9,851,312, 1998; Chem. Abstr. 1998, 130,
13997.
4. Ek, F.; Wistrand, L.-G.; Frejd, T. Tetrahedron 2003, 59, 6759.
5. Flippin, L. A. Tetrahedron Lett. 1991, 32, 6857.
13
6
,125 MHz):
d
¼21.6,124.8,131.1,
1
2
ꢀ
1
1467, 1320, 1306, 1142, 1090, 1017, 839, 818, 618, 545, 483 cm
.
1
9
4.3.8. 1-(2,4-Dimethylphenyl)-5-amino-1H-tetrazole (3h, Table 1,
1
ꢁ
11
ꢁ
1
entry 8). Mp 199–201 C (lit. 199–201 C); H NMR (DMSO-d
6
,
1
1
5
00 MHz):
H), 7.22 (d, J¼8.1 Hz, 1H), 7.28 (s, 1H); C NMR (DMSO-d
25 MHz):
IR (KBr) 3310, 3150, 1651, 1573, 1506, 1458, 1377, 1312, 1134, 1088,
d
¼1.99 (s, 3H), 2.36 (s, 3H), 6.63 (s, 2H), 7.19 (d, J¼8.3 Hz,
13
1
1
6
,
16. Rhonnstad, P.; Wensbo, D. Tetrahedron Lett. 2002, 43, 3137.
d¼16.7, 20.6, 127.1, 127.6, 129.4, 131.7, 134.9, 140.0, 155.6;
17. Jursic, B. S.; LeBlanc, B. W. J. Heterocycl. Chem. 1998, 35, 405.
18. John, E. O.; Kirchmeier, R. L.; Shreeve, J. M. Inorg. Chem. 1989, 28, 4629.
ꢀ
1
19. Zhao-Xu, C.; Heming, X. Int. J. Quantum Chem. 2000, 79, 350.
1027, 868, 823, 614, 562 cm
.
20. Modarresi-Alam, A. R.; Khamooshi, F.; Rostamizadeh, M.; Keykha, H.; Nasrol-
lahzadeh, M.; Bijanzadeh, H. R.; Kleinpeter, E. J. Mol. Struc. 2007, 841, 67.
2
1. (a) Finnegan, W. G.; Henry, R. A.; Lieber, E. J. Org. Chem. 1953, 18, 779; (b) Jensen,
K. A.; Holm, A.; Rachlin, S. Acta Chem. Scand. 1966, 20, 2795; (c) Percival, D. F.;
Herbst, R. M. J. Org. Chem. 1957, 22, 925.
4
.3.9. 1-(2-Methylphenyl)-5-amino-1H-tetrazole (3i, Table 1, en-
ꢁ
11
ꢁ
1
6
try 9). Mp 191–192 C (lit. 191–192 C); H NMR (DMSO-d ,
1
3
3
(
1
00 MHz):
DMSO-d , 75 MHz):
56.1; FTIR (KBr) 3323, 3158,1655,1593,1575,1503,1473,1313,1126,
d
¼2.06 (s, 3H), 6.74 (s, 2H), 7.36–7.51 (m, 4H); C NMR
22. (a) Moderhack, D.; Goos, K.-H.; Preu, L. Chem. Ber. 1990, 123, 1575; (b)
Garbrecht, W. L.; Herbst, R. M. J. Org. Chem. 1953, 18, 1014; (c) Herbst, R. M.;
Roberts, C. W.; Harvill, E. J. Org. Chem. 1951, 16, 139; (d) Marchalin, M.; Martvon,
A. Collect. Czech. Chem. Commun. 1980, 45, 2329.
6
d
¼17.4, 127.7, 127.9, 130.9, 131.8, 132.5, 135.8,
ꢀ
1
1091, 1026, 772, 757, 715, 673, 564 cm ; Anal. Calcd for C H N : C,
8 9 5
2
3. (a) Klich, M.; Teutsch, G. Tetrahedron 1986, 42, 2677; (b) Barlin, G. B. J. Chem.
5
4.84; H, 5.18; N, 39.98. Found: C, 54.92; H, 5.07; N, 40.11.
Soc. B 1967, 641.
2
2
2
4. Ried, W.; Erle, H.-E. Liebigs Ann. Chem. 1982, 201.
5. Batey, R. A.; Powell, D. A. Org. Lett. 2000, 2, 3237.
6. Yu, Y.; Ostresh, J. M.; Houghten, R. A. Tetrahedron Lett. 2004, 45, 7787.
27. (a) Benson, F. R. Chem. Rev. 1947, 47, 1; (b) Koldobskii, G. I.; Ostrovskii, V. A.;
Popavskii, V. S. Chem. Heterocycl. Comp. 1982, 965; (c) Kadaba, P. K. Synthesis
4.3.10. 1-(1-Naphthyl)-5-amino-1H-tetrazole (3j, Table 1, entry
ꢁ
1
10). Mp 220–221 C; H NMR (DMSO-d
6
, 500 MHz):
d
¼6.78 (s, br,
2
8
H), 7.28 (d, J¼8.3 Hz, 1H), 7.62–7.74 (m, 4H), 8.14 (d, J¼8.2 Hz, 1H),
1
973, 71.
8. Katritzky, A. R.; Rogovoy, B. V.; Kovalenko, K. V. J. Org. Chem. 2003, 68, 4941.
29. (a) Kantam, M. L.; Shiva Kumar, K. B.; Sridhar, C. Adv. Synth. Catal. 2005, 347,
212; (b) Jin, T.; Kitahara, F.; Kamijo, S.; Yamamoto, Y. Tetrahedron Lett. 2008, 49,
13
.22 (d, J¼7.5 Hz, 1H); C NMR (DMSO-d
6
, 125 MHz):
d¼157.3,
2
134.8, 131.6, 129.9, 129.8, 129.3, 128.8, 127.9, 126.7, 126.6, 122.7; FTIR
1
(
KBr) 3322, 3139, 1655, 1598, 1577, 1509, 1483, 1397, 1085, 806, 772,
ꢀ1
2824.
6
62 cm ; Anal. Calcd for C11H N : C, 62.56; H, 4.26; N, 33.17.
9 5
3
0. (a) Henry, R. A.; Finnegan, W. G.; Lieber, E. J. Am. Chem. Soc. 1954, 76, 88; (b)
Henry, R. A.; Finnegan, W. G.; Lieber, E. J. Am. Chem. Soc. 1955, 77, 2264.
1. Congreve, M. S. Synlett 1996, 359.
Found: C, 62.64; H, 4.38; N, 33.29.
3
3
2. Vorobiev, A. N.; Gaponik, P. N.; Petrov, P. T. Vestsi Nats. Akad. Navuk Belarusi, Ser.
Khim. Navuk 2003, 2, 50; Chem. Abstr. 2004, 140, 16784g.
Acknowledgements
33. (a) Nasrollahzadeh, M.; Bayat, Y.; Habibi, D.; Moshaee, S. Tetrahedron Lett. 2009,
5
0, 4435; (b) Nasrollahzadeh, M.; Habibi, D.; Shahkarami, Z.; Bayat, Y. Tetra-
The authors are thankful to the Bu-Ali Sina University Council
for partial support of this work.
hedron 2009, 65, 10715; (c) Kamali, T. A.; Bakherad, M.; Nasrollahzadeh, M.;
Farhangi, S.; Habibi, D. Tetrahedron Lett. 2009, 50, 5459; (d) Kamali, T. A.;
Habibi, D.; Nasrollahzadeh, M. Synlett 2009, 2601.
3
3
4. Crutchley, R. J.; Nakicki, M. L. Inorg. Chem. 1989, 28, 1955.
5. (a) Garbrecht, W. L.; Herbst, R. M. J. Org. Chem. 1953, 18, 1003; (b) Garbrecht, W.
L.; Herbst, R. M. J. Org. Chem. 1953, 18, 1022.
References and notes
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9