Efficient synthesis of 5H-indazolo[3,2- b ]-1,3,4-benzotriazepines by a tandem aza-wittig cyclization

Article abstract of DOI:10.1055/s-0032-1316834

5H-Indazolo[3,2-b]-1,3,4-benzotriazepines were directly prepared by the reaction of azides with triphenylphosphine via a tandem aza-Wittig cyclization in good yields. Georg Thieme Verlag Stuttgart - New York.

Full text of DOI:10.1055/s-0032-1316834

PAPER
▌365
paper
Efficient Synthesis of 5H-Indazolo[3,2-b]-1,3,4-benzotriazepines by a Tandem
Aza-Wittig Cyclization
Synthesis of 5H-Indazolo[3,2-b]-1,3,4-benzotriazepines
Fen-Fen Zhao, Hao Zhang, Ming-Wu Ding*
Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Central China Normal University, Wuhan 430079, P. R. of China
Fax +86(27)67862041; E-mail: mwding@mail.ccnu.edu.cn
Received: 01.11.2012; Accepted after revision: 03.12.2012
R
R
Abstract: 5H-Indazolo[3,2-b]-1,3,4-benzotriazepines were direct-
ly prepared by the reaction of azides with triphenylphosphine via a
tandem aza-Wittig cyclization in good yields.
Ph3P
N
N
N
N N PPh3
N3
Key words: 5H-indazolo[3,2-b]-1,3,4-benzotriazepine, aza-Wittig
reaction, tandem reaction, iminophosphorane, azide
1
2
NHR
N
N=PPh3
The 1,3,4-benzotriazepine unit represents an important
structural motif found in some biologically relevant com-
pounds. Many derivatives of this ring system are the sub-
ject of considerable interest as potent CCK2 receptor
antagonist,1–3 antifungal,4 acaricidal,5 and plant protecting
agents.6 Much effort has been invested in the synthesis of
1,3,4-benzotriazepines or fused 1,3,4-benzotriazepines to
deduce structure-activity relationships and discover new
analogues with improved properties.
N
3
Scheme 1
O
R2
R2
R3
NH2
R1
CHO
N3
R1
N
The aza-Wittig reaction has become a powerful synthetic
tool for the preparation of acyclic and heterocyclic com-
pounds.7 Molina et al.8 have reported that indazoles may
be prepared efficiently by a tandem aza-Wittig reaction
(Scheme 1). The indazolyl iminophosphorane 3 was di-
rectly obtained from the abnormal reaction of triphe-
nylphosphine with the o-azidobenzaldimines 1 through
the phosphazide intermediate 2. We envisioned that a pre-
viously unreported ring system, 5H-indazolo[3,2-b]-
1,3,4-benzotriazepine, could be prepared directly by a tan-
dem aza-Wittig reaction without isolating the imino-
phosphorane intermediate, if a suitable azide 1 containing
a carbonyl group was utilized. Continuing our interest in
the synthesis of N-heterocycles via the aza-Wittig reac-
tion,9–17 we wish to report herein an efficient synthesis of
5H-indazolo[3,2-b]-1,3,4-benzotriazepines by a tandem
aza-Wittig reaction in a one-pot reaction.
AcOH
N3
O
R3
4
5
Scheme 2
When azides 5 were treated with triphenylphosphine in
toluene at 0 °C for 1 hour, and then at refluxing tempera-
ture for 2–4 hours, the previously unreported 5H-indazo-
lo[3,2-b]-1,3,4-benzotriazepines 8 were isolated directly
in good yields (78–90%) (Scheme 3, Table 1). The forma-
tion of 8 can be viewed as an initial abnormal reaction be-
tween the azide 5 and triphenylphosphine to create the
phosphazide intermediate 6. Subsequent nucleophilic at-
tack of the central nitrogen atom of the phosphazide moi-
ety on the carbon atom of the azomethine group and
further transformation would lead to iminophosphorane 7.
An intramolecular aza-Wittig reaction of 7 produces cy-
clized compound 8. It is noteworthy that the reaction pro-
ceeds under mild conditions to give the new heterocyclic
ring system 8, and the overall transformation is realized in
a simple one-pot procedure from azides 5 in good overall
yields.
A mixture of 2-azidobenzaldehyde 4 and aromatic amines
was stirred in methanol at room temperature for 1–2 hours
in the presence of acetic acid. The condensation reaction
was carried out smoothly and the products 5 usually pre-
cipitated from the reaction mixture when R3 is an aryl
group (Scheme 2). However, when R3 is an alkyl group
(R3 = Me, Et, Pr), the reaction took place to give a com-
plex mixture, probably due to the side condensation reac-
tion of the alkyl group R3 with 2-azidobenzaldehyde.
The structure of 5H-indazolo[3,2-b]-1,3,4-benzotriaze-
pines 8 was confirmed by their spectral data. For example,
the 1H NMR spectrum of 8a shows a singlet at 9.00 ppm
for the NH group. The signals attributable to the ArHs are
found at 7.78–6.90 ppm as multiplets. In the 13C NMR
spectrum of 8a, the benzotriazepine C=N carbon appears
SYNTHESIS 2013, 45, 0365–0369
Advanced online publication: 17.12.2012
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
X
DOI: 10.1055/s-0032-1316834; Art ID: SS-2012-F0850-OP
© Georg Thieme Verlag Stuttgart · New York

366
F.-F. Zhao et al.
PAPER
Melting points were determined using an X-4 model apparatus and
are uncorrected. Mass spectra were recorded on a Finnigan Trace
MS spectrometer. NMR spectra were recorded in CDCl3 or DMSO-
d6 on a Varian Mercury 600 or 400 spectrometer and resonances rel-
ative to TMS are given. Elementary analyses were conducted on a
Vario EL III elementary analysis instrument.
Table 1 5H-Indazolo[3,2-b]-1,3,4-benzotriazepines 8
Product
R1
R2
R3
Yield (%)a
8a
8b
8c
8d
8e
8f
H
H
Cl
H
H
Cl
Cl
H
H
H
H
4-BrC6H4
82
84
90
78
83
86
81
77
74
80
Cl
Cl
H
Ph
Azides 5a–j; General Procedure
A mixture of 2-azidobenzaldehyde 4 (2 mmol), aromatic amine (2
mmol) and AcOH (2 drops) in MeOH (5 mL) was stirred at r.t. for
1–2 h. The resulting precipitate was collected by filtration to give
the respective azides 5a–j.
Ph
Ph
Br
Br
H
Ph
[2-(2-Azidobenzylideneamino)phenyl](4-bromophenyl)meth-
anone (5a)
Yield: 0.70 g (87%); light yellow solid; mp 172–173 °C.
1H NMR (600 MHz, CDCl3): δ = 8.63 (s, 1 H, N=CH), 7.78 (d,
J = 7.2 Hz, 2 H, ArH), 7.52–6.95 (m, 10 H, ArH).
13C NMR (150 MHz, CDCl3): δ = 196.0, 156.1, 148.6, 140.5, 137.5,
135.4, 132.8, 129.8, 129.7, 128.2, 128.1, 128.0, 126.6, 124.7, 120.1,
119.9, 118.3, 118.1.
Ph
8g
8h
8i
Ph
Cl
Cl
H
4-ClC6H4
4-MeC6H4
4-MeC6H4
8j
MS: m/z (%) = 376 (M+ – N2, 18), 347 (72), 269 (32), 164 (28), 105
(26), 77 (100).
a Isolated yields based on starting azides 5.
Anal. Calcd for C20H13BrN4O: C, 59.28; H, 3.23; N, 13.83. Found:
C, 59.36; H, 3.05; N, 13.57.
R2
R2
[2-(2-Azidobenzylideneamino)-5-chlorophenyl](phenyl)meth-
anone (5b)
R1
Ph3P
R1
N
N
Yield: 0.62 g (86%); light yellow solid; mp 168–169 °C.
COR3
COR3
1H NMR (400 MHz, CDCl3): δ = 8.64 (s, 1 H, N=CH), 7.79 (d,
J = 7.2 Hz, 2 H, ArH), 7.55–6.96 (m, 10 H, ArH).
13C NMR (100 MHz, CDCl3): δ = 196.0, 156.1, 148.7, 140.5, 137.6,
135.4, 131.3, 129.8, 129.7, 128.7, 128.2, 128.1, 126.6, 124.7, 120.1,
120.0, 118.2.
N3
N
N N PPh3
5
6
R2
R2
MS: m/z (%) = 360 (M+, 2), 332 (22), 303 (100), 255 (49), 152 (28),
77 (99).
–N
R3
PPh3
HN
R3
PPh3
H
R1
R1
Anal. Calcd for C20H13ClN4O: C, 66.58; H, 3.63; N, 15.53. Found:
C, 66.32; H, 3.53; N, 15.47.
O
O
N
N
N
N
+
N
N
[2-(2-Azido-5-chlorobenzylideneamino)-5-chlorophenyl](phe-
nyl)methanone (5c)
Yield: 0.66 g (84%); yellow solid; mp 151–152 °C.
1H NMR (600 MHz, CDCl3): δ = 8.55 (s, 1 H, N=CH), 7.78 (d,
J = 7.8 Hz, 2 H, ArH), 7.56–7.06 (m, 9 H, ArH).
13C NMR (150 MHz, CDCl3): δ = 196.1, 154.5, 148.0, 138.9, 137.7,
135.5, 133.1, 132.5, 132.0, 131.5, 130.6, 129.6, 129.1, 128.5, 128.4,
127.8, 119.8, 119.6.
7
R2
HN
R1
R3
N
N
N
MS: m/z (%) = 394 (M+, 3), 366 (16), 337 (42), 289 (25), 164 (12),
105 (18), 77 (100).
8
Scheme 3
Anal. Calcd for C20H12Cl2N4O: C, 60.78; H, 3.06; N, 14.18. Found:
C, 60.92; H, 3.01; N, 14.51.
[2-(2-Azidobenzylideneamino)phenyl](phenyl)methanone (5d)
at 165.1 ppm. The MS spectrum of 8a shows the molecu-
lar ion peak at m/z 388 with 38% abundance.
Yield: 0.51 g (78%); light yellow solid; mp 101–102 °C.
1H NMR (600 MHz, CDCl3): δ = 8.94 (s, 1 H, N=CH), 7.69–7.07
In conclusion, we have developed an efficient and one-pot
synthesis of 5H-indazolo[3,2-b]-1,3,4-benzotriazepines
by a tandem aza-Wittig reaction. The mild reaction condi-
tions and the easy availability of the starting materials
make this method a valuable tool for generating 5H-inda-
zolo[3,2-b]-1,3,4-benzotriazepines, which are of consid-
erable interest as potential biologically active compounds
or pharmaceuticals.
(m, 13 H, ArH).
13C NMR (150 MHz, CDCl3,): δ = 197.6, 155.9, 150.4, 140.4,
138.1, 133.8, 132.6, 132.5, 131.5, 129.8, 129.1, 129.0, 128.1, 128.0,
125.7, 124.7, 118.8, 118.2.
MS: m/z (%) = 326 (M+, 3), 298 (18), 269 (100), 221 (52), 152 (23),
77 (69).
Anal. Calcd for C20H14N4O: C, 73.61; H, 4.32; N, 17.17. Found: C,
73.44; H, 4.16; N, 17.24.
Synthesis 2013, 45, 365–369
© Georg Thieme Verlag Stuttgart · New York

PAPER
Synthesis of 5H-Indazolo[3,2-b]-1,3,4-benzotriazepines
367
[2-(2-Azidobenzylideneamino)-5-bromophenyl](phenyl)meth-
anone (5e)
Yield: 0.62 g, 77%; light yellow solid; mp 160–161 °C.
[2-(2-Azidobenzylideneamino)-5-chlorophenyl](4-tolyl)meth-
anone (5j)
Yield: 0.60 g (80%); light yellow solid; mp 171–172 °C.
1H NMR (400 MHz, CDCl3): δ = 8.63 (s, 1 H, N=CH), 7.79 (d,
J = 7.2 Hz, 2 H, ArH), 7.63–6.96 (m, 10 H, ArH).
1H NMR (400 MHz, CDCl3): δ = 8.64 (s, 1 H, N=CH), 7.69 (d,
J = 8.4 Hz, 2 H, ArH), 7.54–6.98 (m, 9 H, ArH).
13C NMR (100 MHz, CDCl3): δ = 195.8, 154.6, 138.9, 137.7, 135.8,
134.5, 133.1, 132.5, 131.9, 130.6, 129.6, 128.5, 128.4, 128.2, 127.8,
120.1, 119.7, 119.6.
13C NMR (100 MHz, CDCl3): δ = 195.6, 156.2, 148.6, 143.9, 140.5,
135.7, 134.9, 132.7, 131.4, 131.1, 130.0, 129.0, 128.6, 128.2, 126.7,
124.7, 120.1, 118.3, 21.7.
MS: m/z (%) = 405 (M+, 1), 376 (8), 347 (51), 301 (24), 105 (31),
77 (100).
MS: m/z (%) = 346 (M+ – N2, 21), 317 (69), 255 (67), 163 (24), 91
(100).
Anal. Calcd for C20H13BrN4O: C, 59.28; H, 3.23; N, 13.83. Found:
C, 58.96; H, 2.95; N, 13.91.
Anal. Calcd for C21H15ClN4O: C, 67.29; H, 4.03; N, 14.95. Found:
C, 67.44; H, 3.86; N, 14.87.
[2-(2-Azido-5-chlorobenzylideneamino)-5-bromophenyl](phe-
nyl)methanone (5f)
5H-Indazolo[3,2-b]-1,3,4-benzotriazepines 8a–j;
General Procedure
Yield: 0.63 g (72%); light yellow solid; mp 174–175 °C.
To a solution of azide 5 (2 mmol) in anhyd toluene (10 mL) was
added dropwise a solution of Ph3P (0.52 g, 2 mmol) in toluene (10
mL) at 0 °C. The reaction mixture was stirred for 2 h and then re-
fluxed for 2–4 h. The solvent was removed and the residue was
chromatographed [petroleum ether (bp 60–90 °C)–Et2O, 1:1] on a
silica gel column to give the respective 5H-indazolo[3,2-b]-1,3,4-
benzotriazepines 8a–j.
1H NMR (400 MHz, CDCl3): δ = 8.55 (s, 1 H, N=CH), 7.78 (d,
J = 7.6 Hz, 2 H, ArH), 7.69–7.03 (m, 9 H, ArH).
13C NMR (100 MHz, CDCl3): δ = 195.9, 154.7, 154.4, 148.5, 138.9,
137.7, 135.8, 134.5, 133.2, 132.7, 132.3, 131.9, 130.6, 129.7, 129.6,
128.5, 128.2, 119.7.
MS: m/z (%) = 440 (M+, 3), 410 (7), 383 (25), 335 (17), 152 (22),
105 (43), 77 (100).
12-(4-Bromophenyl)-5H-indazolo[3,2-b]-1,3,4-benzotriazepine
(8a)
Anal. Calcd for C20H12BrClN4O: C, 54.63; H, 2.75; N, 12.74.
Found: C, 54.81; H, 2.49; N, 12.52.
Yield: 0.64 g (82%); yellow solid; mp 242–244 °C.
1H NMR (600 MHz, DMSO-d6): δ = 9.00 (s, 1 H, NH), 7.78–7.52
(m, 6 H, ArH), 7.36 (d, J = 7.8 Hz, 1 H, ArH), 7.23 (d, J = 7.2 Hz,
1 H, ArH), 7.17–6.90 (m, 4 H, ArH).
13C NMR (150 MHz, DMSO-d6): δ = 165.1, 152.9, 147.6, 136.9,
136.8, 134.0, 133.0, 131.6, 131.3, 127.1, 124.6, 123.4, 123.3, 120.4,
120.0, 119.8, 116.5, 109.4.
[2-(2-Azido-5-chlorobenzylideneamino)phenyl](phenyl)meth-
anone (5g)
Yield: 0.58 g (80%); light yellow solid; mp 162–163 °C.
1H NMR (400 MHz, CDCl3): δ = 8.55 (s, 1 H, N=CH), 7.78 (d,
J = 7.6 Hz, 2 H, ArH), 7.58–7.05 (m, 10 H, ArH).
13C NMR (100 MHz, CDCl3): δ = 198.2, 154.3, 138.8, 138.3, 134.0,
132.7, 132.3, 131.7, 130.6, 129.7, 129.4, 128.2, 127.9, 126.2, 119.6,
118.5.
MS: m/z (%) = 388 (M+, 38), 361 (94), 281 (89), 205 (35), 178 (67),
151 (59), 102 (45), 76 (100).
Anal. Calcd for C20H13BrN4: C, 61.71; H, 3.37; N, 14.39. Found: C,
61.59; H, 3.10; N, 14.20.
MS: m/z (%) = 360 (M+, 2), 332 (18), 303 (87), 255 (57), 152 (32),
105 (38), 77 (100).
2-Chloro-12-phenyl-5H-indazolo[3,2-b]-1,3,4-benzotriazepine
(8b)
Yield: 0.58 g (84%); yellow solid; mp 225–226 °C.
Anal. Calcd for C20H13ClN4O: C, 66.58; H, 3.63; N, 15.53. Found:
C, 66.52; H, 3.49; N, 15.29.
1H NMR (400 MHz, DMSO-d6): δ = 9.13 (s, 1 H, NH), 7.76 (d,
J = 8.4 Hz, 1 H, ArH), 7.63–7.56 (m, 6 H, ArH), 7.38 (d, J = 8.4 Hz,
1 H, ArH), 7.26–6.89 (m, 4 H, ArH).
[2-(2-Azidobenzylideneamino)-5-chlorophenyl](4-chlorophe-
nyl)methanone (5h)
Yield: 0.59 g (75%); light yellow solid; mp 198–199 °C.
13C NMR (100 MHz, DMSO-d6): δ = 164.6, 151.8, 147.7, 137.2,
136.5, 133.6, 132.1, 131.2, 129.3, 128.7, 127.2, 127.1, 125.3, 122.1,
120.1, 119.9, 116.6, 109.5.
MS: m/z (%) = 344 (M+, 38), 315 (100), 281 (71), 177 (31), 140
(39), 77 (20).
1H NMR (400 MHz, CDCl3): δ = 8.64 (s, 1 H, N=CH), 7.73 (d,
J = 8.4 Hz, 2 H, ArH), 7.52–7.00 (m, 9 H, ArH).
13C NMR (100 MHz, CDCl3): δ = 194.9, 156.2, 148.6, 145.9, 140.6,
139.4, 135.9, 135.1, 132.9, 131.7, 131.7, 131.2, 128.7, 128.6, 128.0,
124.9, 120.0, 118.4.
MS: m/z (%) = 366 (M+ – N2, 13), 337 (35), 268 (26), 255 (59), 111
(100).
Anal. Calcd for C20H13ClN4: C, 69.67; H, 3.80; N, 16.25. Found: C,
69.35; H, 3.78; N, 16.41.
Anal. Calcd for C20H12Cl2N4O: C, 60.78; H, 3.06; N, 14.18. Found:
C, 60.54; H, 2.85; N, 14.11.
2,7-Dichloro-12-phenyl-5H-indazolo[3,2-b]-1,3,4-benzotriaze-
pine (8c)
Yield: 0.68 g (90%); yellow solid; mp 239–240 °C.
[2-(2-Azidobenzylideneamino)phenyl](4-tolyl)methanone (5i)
Yield: 0.50 g (73%); light yellow solid; mp 145–147 °C.
1H NMR (400 MHz, DMSO-d6): δ = 9.11 (s, 1 H, NH), 7.88 (s, 1 H,
ArH), 7.64–7.54 (m, 6 H, ArH), 7.45 (d, J = 9.2 Hz, 1 H, ArH), 7.23
(d, J = 8.4 Hz, 1 H, ArH), 7.17 (d, J = 9.2 Hz, 1 H, ArH), 6.89 (s, 1
H, ArH).
13C NMR (100 MHz, DMSO-d6): δ = 165.3, 151.5, 145.8, 137.0,
136.4, 133.7, 132.3, 131.3, 129.4, 128.7, 128.1, 127.2, 125.2, 124.3,
122.1, 118.9, 118.7, 109.6.
1H NMR (600 MHz, CDCl3): δ = 8.64 (s, 1 H, N=CH), 7.70 (d,
J = 7.8 Hz, 2 H, ArH), 7.56–7.13 (m, 10 H, ArH).
13C NMR (150 MHz, CDCl3): δ = 197.2, 155.8, 150.3, 143.4, 140.3,
137.1, 135.5, 134.1, 132.3, 131.2, 130.0, 128.9, 128.7, 126.9, 125.5,
124.6, 118.7, 118.1, 21.6.
MS: m/z (%) = 312 (M+ – N2, 18), 298 (47), 268 (21), 255 (73), 77
(100).
MS: m/z (%) = 378 (M+, 77), 351 (100), 315 (94), 177 (52).
Anal. Calcd for C20H12Cl2N4: C, 63.34; H, 3.19; N, 14.77. Found:
C, 63.57; H, 2.95; N, 14.84.
Anal. Calcd for C21H16N4O: C, 74.10; H, 4.74; N, 16.46. Found: C,
74.27; H, 4.75; N, 16.25.
© Georg Thieme Verlag Stuttgart · New York
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368
F.-F. Zhao et al.
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12-Phenyl-5H-indazolo[3,2-b]-1,3,4-benzotriazepine (8d)
MS: m/z (%) = 378 (M+, 41), 349 (41), 178 (28), 77 (18).
Yield: 0.48 g (78%); yellow solid; mp 237–238 °C.
Anal. Calcd for C20H12Cl2N4: C, 63.34; H, 3.19; N, 14.77. Found:
C, 63.09; H, 3.34; N, 14.51.
1H NMR (400 MHz DMSO-d6): δ = 8.99 (s, 1 H, NH), 7.78 (d,
J = 8.4 Hz, 1 H, ArH), 7.62–7.50 (m, 6 H, ArH), 7.37 (d, J = 8.4 Hz,
1 H, ArH), 7.23 (d, J = 8.0 Hz, 1 H, ArH), 7.18 (t, J = 8.0 Hz, 1 H,
ArH), 7.08 (t, J = 7.6 Hz, 1 H, ArH), 6.93–6.89 (m, 2 H, ArH).
13C NMR (100 MHz, DMSO-d6): δ = 166.1, 152.9, 147.5, 137.6,
136.9, 133.9, 133.1, 130.9, 129.3, 128.5, 127.0, 123.8, 123.2, 120.3,
119.9, 119.7, 116.5, 109.4.
2-Chloro-12-(4-tolyl)-5H-indazolo[3,2-b]-1,3,4-benzotriaze-
pine (8i)
Yield: 0.53 g (74%); yellow solid; mp 242–243 °C.
1H NMR (400 MHz, DMSO-d6): δ = 9.12 (s, 1 H, NH), 7.77 (d,
J = 8.4 Hz, 1 H, ArH), 7.59–7.52 (m, 3 H, ArH), 7.39 (d, J = 8.8 Hz,
1 H, ArH), 7.36–6.90 (m, 6 H, ArH), 2.40 (s, 3 H, CH3)
13C NMR (100 MHz, DMSO-d6): δ = 164.6, 151.8, 147.6, 141.2,
136.5, 134.3, 132.2, 132.0, 129.5, 129.1, 129.0, 127.0, 125.4, 122.2,
120.1, 119.9, 117.0, 109.5, 21.0.
MS: m/z (%) = 310 (M+, 33), 281 (100), 178 (13), 77 (13).
Anal. Calcd for C20H14N4: C, 77.40; H, 4.55; N, 18.05. Found: C,
76.28; H, 4.33; N, 18.19.
MS: m/z (%) = 358 (M+, 66), 329 (55), 315 (100), 295 (75), 177
(31), 110 (22), 77 (19).
2-Bromo-12-phenyl-5H-indazolo[3,2-b]-1,3,4-benzotriazepine
(8e)
Yield: 0.65 g (83%); yellow solid; mp 207–208 °C.
Anal. Calcd for C21H15ClN4: C, 70.29; H, 4.21; N, 15.61. Found: C,
70.47; H, 4.17; N, 15.36.
1H NMR (400 MHz, CDCl3): δ = 7.69 (d, J = 7.2 Hz, 2 H, ArH),
7.54–7.38 (m, 6 H, ArH), 7.19 (t, J = 7.2 Hz, 1 H, ArH), 7.08 (s, 1
H, NH), 7.01–6.83 (m, 3 H, ArH).
13C NMR (100 MHz, DMSO-d6): δ = 164.5, 152.2, 147.7, 137.2,
136.4, 135.0, 131.1, 129.3, 128.7, 127.2, 125.7, 122.4, 120.1, 119.9,
116.6, 114.7, 109.5.
12-(4-Tolyl)-5H-indazolo[3,2-b]-1,3,4-benzotriazepine (8j)
Yield: 0.52 g (80%); yellow solid; mp 228–229 °C.
1H NMR (600 MHz, DMSO-d6): δ = 8.96 (s, 1 H, NH), 7.77 (d,
J = 7.8 Hz, 1 H, ArH), 7.51–7.34 (m, 6 H, ArH), 7.23 (d, J = 7.8 Hz,
1 H, ArH), 7.17 (d, J = 6.6 Hz, 1 H, ArH), 7.07–6.90 (m, 3 H, ArH),
2.40 (s, 3 H, CH3).
13C NMR (150 MHz, DMSO-d6): δ = 166.1, 152.9, 147.4, 140.9,
136.9, 134.7, 133.8, 133.1, 129.3, 129.1, 126.9, 123.9, 123.2, 120.3,
119.9, 119.7, 116.4, 109.4, 21.0.
MS: m/z (%) = 388 (M+, 40), 361 (74), 281 (100), 177 (38), 151
(39), 77 (37).
Anal. Calcd for C20H13BrN4: C, 61.71; H, 3.37; N, 14.39. Found: C,
61.78; H, 3.12; N, 14.27.
2-Bromo-7-chloro-12-phenyl-5H-indazolo[3,2-b]-1,3,4-benzo-
triazepine (8f)
MS: m/z (%) = 324 (M+, 48), 295 (100), 281 (31), 154 (41), 77 (35).
Anal. Calcd for C21H16N4: C, 77.76; H, 4.97; N, 17.27. Found: C,
77.74; H, 5.13; N, 17.04.
Yield: 0.73 g (86%); yellow solid; mp 209–210 °C.
1H NMR (400 MHz, DMSO-d6): δ = 9.11 (s, 1 H, NH), 7.89 (s, 1 H,
ArH), 7.66–7.51 (m, 6 H, ArH), 7.42 (d, J = 8.8 Hz, 1 H, ArH),
7.14–6.95 (m, 3 H, ArH).
13C NMR (100 MHz, DMSO-d6): δ = 165.1, 151.9, 145.8, 137.1,
136.5, 136.3, 135.0, 131.2, 129.3, 128.6, 128.0, 125.5, 124.3, 122.4,
122.3, 118.9, 114.8, 109.7.
Acknowledgment
We gratefully acknowledge the financial support of this work by the
National Natural Science Foundation of China (No. 21032001,
21172085).
MS: m/z (%) = 424 (M+, 48), 395 (92), 315 (100), 177 (54), 151
(35), 140 (30), 77 (21).
Supporting Information for this article is available online at
Anal. Calcd for C20H12BrClN4: C, 56.70; H, 2.85; N, 13.22. Found:
C, 56.57; H, 2.60; N, 13.41.
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7-Chloro-12-phenyl-5H-indazolo[3,2-b]-1,3,4-benzotriazepine
(8g)
Yield: 0.56 g (81%); yellow solid; mp 251–252 °C.
References
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1H NMR (400 MHz, DMSO-d6): δ = 9.01 (s, 1 H, NH), 7.91 (s, 1 H,
ArH), 7.59–7.53 (m, 6 H, ArH), 7.43 (d, J = 9.6 Hz, 1 H, ArH), 7.23
(d, J = 8.0 Hz, 1 H, Ar–H), 7.14 (d, J = 9.2 Hz, 1 H, ArH), 7.08 (d,
J = 6.8 Hz, 1 H, ArH), 6.90 (d, J = 7.6 Hz, 1 H, ArH).
13C NMR (100 MHz, DMSO-d6): δ = 166.9, 152.6, 145.8, 145.7,
137.5, 136.9, 134.1, 133.3, 131.2, 129.5, 128.9, 128.6, 128.0, 124.1,
123.8, 120.5, 118.8, 109.6.
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Anal. Calcd for C20H13ClN4: C, 69.67; H, 3.80; N, 16.25. Found: C,
69.84; H, 3.94; N, 16.21.
2-Chloro-12-(4-chlorophenyl)-5H-indazolo[3,2-b]-1,3,4-benzo-
triazepine (8h)
Yield: 0.58 g (77%); yellow solid; mp 198–199 °C.
1H NMR (400 MHz, DMSO-d6): δ = 9.16 (s, 1 H, NH), 7.77 (d,
J = 8.4 Hz, 1 H, ArH), 7.66–7.57 (m, 5 H, ArH), 7.39 (d, J = 8.4 Hz,
1 H, ArH), 7.26–6.93 (m, 4 H, ArH).
13C NMR (100 MHz, DMSO-d6): δ = 163.5, 151.8, 147.8, 136.5,
136.0, 133.7, 132.0, 131.1, 128.8, 127.3, 127.2, 124.9, 122.1, 120.1,
120.0, 116.6, 109.5.
Synthesis 2013, 45, 365–369
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