A convenient synthesis of 1,4,5-trisubstituted 1,2,3-triazoles via 1,3-dipolar cycloaddition/coupling of alkynes, phenylboronic acids, and sodium azide catalyzed by Cu(I)/Cu(II)

Article abstract of DOI:10.1055/s-2007-968007

A series of 1,4,5-trisubstituted 1,2,3-triazoles was prepared simply and conveniently via 1,3-dipolar cycloaddition/coupling reaction of terminal alkynes, phenylboronic acids and sodium azide in 1,4-dioxane-water using CuI/CuSO₄ as catalyst. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2007-968007

278
LETTER
A Convenient Synthesis of 1,4,5-Trisubstituted 1,2,3-Triazoles via 1,3-Dipolar
Cycloaddition/Coupling of Alkynes, Phenylboronic Acids, and Sodium Azide
Catalyzed by Cu(I)/Cu(II)
C
onvenient Synthe
o
sis of 1,4,5-T
n
risubstituted
g
1,2,3-Triazoles Yang,a Na Fu,a Zenglu Liu,b Ying Li,a Baohua Chen*a
a
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. of China
b
Pharmacy College of Shanghai Jiao Tong University, Shanghai 200030, P. R. of China
Fax +86(931)8912582; E-mail: chbh@lzu.edu.cn
Received 19 September 2006
It was reported that phenylboronic acids can be converted
into the corresponding halides via a displacement reac-
tion.15 In this communication, we report an efficient and
safe one-pot procedure for the regioselective formation of
1,4,5-trisubstituted 1,2,3-triazoles via Cu(I)/Cu(II)-cata-
lyzed 1,3-dipolar cycloaddition/coupling reaction of
terminal alkynes, phenylboronic acids and sodium azide.
Abstract: A series of 1,4,5-trisubstituted 1,2,3-triazoles was pre-
pared simply and conveniently via 1,3-dipolar cycloaddition/cou-
pling reaction of terminal alkynes, phenylboronic acids and sodium
azide in 1,4-dioxane–water using CuI/CuSO4 as catalyst.
Key words: triazole, cycloaddition/coupling, phenylboronic acid,
copper catalyst, alkyne
We first conducted experiments to define the require-
ments for solvent systems using CuI as catalyst. Reactions
were performed in various solvents containing water in-
cluding acetone, MeCN, DMF, DMSO, EtOH, MeOH,
THF, t-BuOH, and 1,4-dioxane (entries 1–12 in Table 1).
Initial studies showed that the reaction could be per-
formed in almost all these solvent systems; however, the
1,4-dioxane–water (2:1) solvent system turned out to be
the best. As shown in Table 1, CuSO4 showed no catalytic
activity for cycloaddition/coupling of 1a, 2a and 3, but a
mixture of CuSO4 and CuI exhibited slightly better cata-
lytic activity (entries 13 and 14 in Table 1).
1,2,3-Triazoles have received significant attention as
biologically important heterocycles. They possess many
interesting antibacterial,1 antiallergic,2 anti-HIV activity,3
and antineoplastic activity.4 Additionally, they have been
applied widely in herbicides, fungicides, and dyes etc.5
The typical procedure for preparing 1,2,3-triazoles is via
1,3-dipolar cycloaddition of azides and alkynes proposed
by Huisgen, yet this reaction often affords a mixture of
1,4- and 1,5-disubstituted isomers.6 Recently, alternative
methods that improve regioselectivity have been devel-
oped. For example, Sharpless, Fokin, and co-workers
developed Cu(I)-catalyzed cycloaddition of azides with
terminal alkynes to synthesize 1,4-disubstituted 1,2,3-tri-
azole.7 They also reported the regioselective synthesis of
1,5-disubstituted 1,2,3-triazoles and 1,4,5-trisubstituted
1,2,3-triazoles via the addition of bromomagnesium
acetylides to azides.8 Yamamoto and co-workers de-
scribed the synthesis of triazoles using a palladium
catalyst9 or a Pd(0)–Cu(I) bimetallic catalyst.10 Very re-
cently, Porco Jr. and co-workers described a 1,3-dipolar
We next examined the cycloaddition/coupling some of
phenylboronic acids and terminal alkynes under the
optimum conditions. As can be seen from Table 2, the
phenylethyne substrates, 4-nitrophenylethyne (2c) and 4-
acetylphenylethyne (2d), bearing an electron-withdraw-
ing group in phenyl ring failed to react with phenyl-
boronic acids and sodium azide to produce 4 (entries 3, 4,
8, and 11 in Table 2). 4-Methoxyphenylethyne (2a) and
phenylethyne (2b) reacted with substrates 1a, 1b,1c and
1d, and the corresponding products 4a, 4d, 4f, 4i and 4b,
4e, 4g, 4j were isolated in 63%, 68%, 78%, 57% and 55%,
65%, 74%, 52% yields, respectively (entries 1, 2, 6, 7, 9,
10, 13, and 14 in Table 2).16 Thus, electron-rich phenyl-
ethynes gave better results in this reaction. Alkyl ethyne
can also give product 4 (entries 5 and 12 in Table 2).16
Phenylboronic acid substrates bearing an electron-with-
drawing group usually led to higher yields (e.g., entries 1,
6, 9, and 13 in Table 2).16 By-product diyne was observed
in all reactions, thus the moderate isolated yields were
likely due to competing Glaser coupling (diyne formation,
Equation 1).17
cycloaddition/coupling
reaction
catalyzed
by
Cu(MeCN)4PF6 for the synthesis of 1,2,3-triazoles.11
Although organic azides are generally safe compounds,
those of low molecular weight are sometimes unstable and
difficult to handle.12 Thus, methodologies that avoid the
isolation of organic azides are desirable. Click chemistry
is a useful way of making diverse collections of triazoles,
and is showing a growing impact on drug discovery.13
Fokin reported the synthesis of triazoles by a convenient
one-pot procedure from a variety of available aromatic
and aliphatic halides without isolating the potentially un-
stable organic azide intermediates.14
2
SYNLETT 2007, No. 2, pp 0278–0282
0
1.
0
2.
2
0
0
7
R
R
R
Advanced online publication: 24.01.2007
DOI: 10.1055/s-2007-968007; Art ID: W19406ST
© Georg Thieme Verlag Stuttgart · New York
Equation 1 Diyne formation

LETTER
Convenient Synthesis of 1,4,5-Trisubstituted 1,2,3-Triazoles
279
Table 1 Synthesis of 1,2,3-Triazole 4a in Various Solvent Systems and Catalystsa
MeO
N
N
N
+
+
NaN3
B(OH)2
MeO
2
MeO
1a
2a
3
4a
Entry
Catalystb
Solvent
Time (h)
24
4, Yieldc (%)
1
2
I
acetone–H2O (2:1)
MeCN–H2O (2:1)
DMF–H2O (2:1)
44
I
5
42
3
I
24
traced
traced
30
4
I
DMSO–H2O (2:1)
EtOH–H2O (2:1)
24
5
I
24
6
I
MeOH–H2O (2:1)
THF–H2O (2:1)
24
43
7
I
24
42
8
I
t-BuOH–H2O (2:1)
1,4-dioxane–H2O (2:1)
1,4-dioxane–H2O (1:1)
1,4-dioxane–H2O (1:2)
1,4-dioxane
24
17
9
I
24
55
10
11
12
13
14
I
24
51
I
24
42
I
24
13
II
III
1,4-dioxane–H2O (2:1)
1,4-dioxane–H2O (2:1)
24
none
63
12
a All reactions were performed with 1a (1 equiv), 2a (2.2 equiv) and 3 (1.5 equiv) under conditions as indicated.
b I: CuI (10%), II: CuSO4·5H2O (20%), III: CuI (10%), CuSO4·5H2O (20%).
c Isolated yield after column chromatography on silica gel.
d Detected by TLC.
For the reaction, we initially reasoned that the product 4 The structures of compounds 4a–j were fully identified by
1
may be formed by an initial Glaser coupling and sub- their IR, H NMR, and 13C NMR spectra. The X-ray
sequent 1,3-dipolar cycloaddition. However, treatment of crystal structure of 4b further confirmed their structures
1,4-diphenylbuta-1,3-diyne with sodium azide and (Figure 1).18
phenylboronic acid led to no reaction (Equation 2). Treat-
ment of disubstituted triazole with alkyne in the presence
of CuI and CuSO4·5H2O led to no reaction, either
(Equation 3). Proposed mechanism for the catalytic cycle
is shown in Scheme 1.
N
N
N
N
N
N
+
N
N
B(OH)
2, NaN3
N
Equation 3
Equation 2
Synlett 2007, No. 2, 278–282 © Thieme Stuttgart · New York

280
D. Yang et al.
LETTER
Table 2 Synthesis of 1,4,5-Trisubstituted 1,2,3-Triazole 4 from Various Alkynes, Phenylboronic Acids and Sodium Azidea
R1
N
CuI, CuSO4
N
R1
H
+
B(OH)2
+
NaN3
2
N
R
1,4-dioxane–H2O (2:1), r.t.
R1
R
1a–d
2a–e
3
4a–j
Entry
1
Phenylboronic acid 1
Terminal alkyne 2
Time (h)
12
Yieldb (%) of 4
4a, 63
MeO
B(OH)2
1a
1a
2a
2
3
4
12
24
24
4b, 55
2b
1a
1a
–
–
O2N
2c
O
2d
5
6
1a
12
12
4c, 40
4d, 68
C5H11
2e
2a
Cl
B(OH)2
1b
1b
7
8
9
2b
2c
2a
12
24
12
4e, 65
–
1b
4f, 78
O
B(OH)2
1c
1c
10
11
12
13
2b
2d
2e
2a
12
24
12
12
4g, 74
–
1c
1c
4h, 45
4i, 57
B(OH)2
OMe
1d
1d
14
2b
12
4j, 52
a All reactions were performed with 1a (1 equiv), 2 (2.2 equiv) and 3 (1.5 equiv) under conditions as indicated.
b Isolated yield after column chromatography on silica gel.
In conclusion, a novel and direct method for synthesizing Acknowledgment
1,4,5-trisubstituted 1,2,3-triazoles directly from a variety
The authors are grateful for the project sponsorship by the Scientific
Research Foundation for the Returned Overseas Chinese Scholars,
State Education Ministry.
of phenylboronic acids, sodium azide, and some terminal
alkynes has been developed. The procedure does not
require isolating of the azide intermediates and it has a
series of advantages, such as, it is safe, efficient, conve-
nient, easy operating and environmentally benign.
Synlett 2007, No. 2, 278–282 © Thieme Stuttgart · New York

LETTER
Convenient Synthesis of 1,4,5-Trisubstituted 1,2,3-Triazoles
281
R
R
R1
LnCu
R1
N
N
N
N
N
N
R1
R1
[CuLn]+
B(OH)2
NaN3
R
R1
H
2
R1
R1
R1
CuLn
R1
Scheme 1 Proposed mechanism
(5) Wamhoff, H. In Comprehensive Heterocyclic Chemistry,
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Oxford, 1984, 669.
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Lett. 2002, 43, 9707.
Figure 1 X-ray crystal structure of 1,4-diphenyl-5-(2-phenylethy-
nyl)-1H-1,2,3-triazole (4b)
(10) Kamijo, S.; Jin, T.; Huo, Z.; Yamamoto, Y. J. Am. Chem.
Soc. 2003, 125, 7786.
(11) Gerard, B.; Ryan, J.; Beeler, A. B.; Porco, J. A. Jr.
Tetrahedron 2006, 62, 6405.
(12) Scriven, E. F. V.; Turnbull, K. Chem. Rev. 1988, 88, 297.
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8, 1128.
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6, 3897.
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A. Synlett 1998, 141.
(16) Synthesis of 4-(4-Methoxyphenyl)-5-[2-(4-methoxy-
phenyl)ethynyl]-1-phenyl-1H-1,2,3-triazole (4a); Typical
Procedure: A mixture of 1a (50.0 mg, 0.41 mmol), 2a
(118.9 mg, 0.90 mmol), sodium azide (3; 40.3 mg, 0.62
mmol), CuI (7.8 mg, 0.041 mmol) and CuSO4·5H2O (20.5
mg, 0.082 mmol) in 1,4-dioxane (10 mL) and H2O (5 mL)
was stirred overnight. Then, the reaction mixture was diluted
with H2O (20 mL) and was extracted with CH2Cl2 (3 × 20
mL). The combined organic extracts were dried over
MgSO4, filtered and concentrated. The residue was purified
by column chromatography (PE–EtOAc, 10:1) to afford 4a
(98.5 mg, 63%) as a white solid; mp 86–88 °C. IR (KBr):
References and Notes
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Spicer, B. A. J. Med. Chem. 1983, 26, 251. (b) Buckle, D.
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Synlett 2007, No. 2, 278–282 © Thieme Stuttgart · New York

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D. Yang et al.
LETTER
2216 cm–1. 1H NMR (300 MHz, CDCl3): d = 3.83 (s, 3 H),
3.87 (s, 3 H), 6.89 (d, J = 9.3 Hz, 2 H), 7.03 (d, J = 8.7 Hz,
2 H), 7.40 (d, J = 8.7 Hz, 2 H), 7.50–7.60 (m, 3 H), 7.88 (d,
J = 8.1 Hz, 2 H), 8.21 (d, J = 9.3 Hz, 2 H). 13C NMR (75
MHz, CDCl3): d = 55.3 (CH3), 55.4 (CH3), 75.4 (C), 102.0
(C), 113.6 (C), 114.1 (CH), 114.3 (CH), 116.3 (C), 122.9
(C), 123.7 (CH), 127.8 (CH), 129.2 (CH), 129.7 (CH), 133.0
(CH), 136.7 (C), 148.1 (C), 160.0 (C), 160.6 (C). EI–MS:
m/z = 381 [M+], 353 [M – N2]+. Anal. Calcd for C24H19N3O2:
C, 75.57; H, 5.02; N, 11.02. Found: C, 75.50; H, 4.99; N,
10.98.
1,4-Diphenyl-5-(2-phenylethynyl)-1H-1,2,3-triazole(4b):
white solid; mp 105–107 °C. IR (KBr): 2215 cm–1. 1H NMR
(300 MHz, CDCl3): d = 7.38–7.60 (m, 11 H), 7.88 (d, J = 8.4
Hz, 2 H), 8.28 (d, J = 7.5 Hz, 2 H). 13C NMR (75 MHz,
CDCl3): d = 76.4 (C), 102.0 (C), 116.8 (C), 121.4 (C), 123.8
(CH), 126.5 (CH), 128.6 (CH), 128.7 (CH), 128.7 (CH),
129.2 (CH), 129.4 (CH), 129.6 (CH), 130.1 (C), 131.4 (CH),
136.5 (C), 148.5 (C). EI–MS: m/z = 321 [M+], 293 [M –N2]+.
Anal. Calcd for C22H15N3: C, 82.22; H, 4.70; N, 13.08.
Found: C, 82.16; H, 4.71; N, 13.04.
5-(Hept-1-ynyl)-4-pentyl-1-phenyl-1H-1,2,3-triazole
(4c): liquid. IR (KBr): 2236 cm–1. 1H NMR (300 MHz,
CDCl3): d = 0.87–0.94 (m, 6 H), 1.26–1.42 (m, 8 H), 1.53–
1.60 (m, 2 H), 1.76–1.81 (m, 2 H), 2.45 (t, J = 7.0 Hz, 2 H),
2.79 (t, J = 7.6 Hz, 2 H), 7.44–7.53 (m, 3 H), 7.78 (d, J = 6.9
Hz, 2 H). 13C NMR (75 MHz, CDCl3): d = 13.87 (CH3),
13.94 (CH3), 19.6 (CH2), 22.1 (CH2), 22.3 (CH2), 25.4
(CH2), 27.7 (CH2), 28.5 (CH2), 30.9 (CH2), 31.4 (CH2), 66.9
(C), 103.1 (C), 118.7 (C), 123.3 (CH), 128.8 (CH), 129.0
(CH), 136.8 (C), 151.2 (C). EI–MS: m/z = 309 [M+], 281
[M – N2]+. Anal. Calcd for C20H27N3: C, 77.63; H, 8.79; N,
13.58. Found: C, 77.56; H, 8.77; N, 13.55.
1-(4-Chlorophenyl)-4-(4-methoxyphenyl)-5-[2-(4-
methoxyphenyl)ethynyl]-1H-1,2,3-triazole (4d): white
solid; mp 150–152 °C. IR (KBr): 2214 cm–1. 1H NMR (300
MHz, CDCl3): d = 3.84 (s, 3 H), 3.87 (s, 3 H), 6.91 (d, J =
9.0 Hz, 2 H), 7.02 (d, J = 8.7 Hz, 2 H), 7.41 (d, J = 9.0 Hz, 2
H), 7.54 (d, J = 8.7 Hz, 2 H), 7.84 (d, J = 9.0 Hz, 2 H), 8.20
(d, J = 9.3 Hz, 2 H). 13C NMR (75 MHz, CDCl3): d = 55.3
(CH3), 55.4 (CH3), 75.2 (C), 102.4 (C), 113.3 (C), 114.1
(CH), 114.4 (CH), 116.2 (C), 122.7 (C), 124.8 (CH), 127.8
(CH), 129.4 (CH), 133.1 (CH), 135.1 (C), 135.2 (C), 148.3
(C), 160.0 (C), 160.7 (C). EI–MS: m/z = 415 [M+], 387 [M –
N2]+. Anal. Calcd for C24H18ClN3O2: C, 69.31; H, 4.36; N,
10.10. Found: C, 69.27; H, 4.32; N, 10.08.
137.0 (C), 140.0 (C), 148.5 (C), 160.1 (C), 160.8 (C), 196.8
(C). EI–MS: m/z = 423 [M+], 395 [M –N2]+. Anal. Calcd for
C26H21N3O3: C, 73.74; H, 5.00; N, 9.92. Found: C, 73.71; H,
5.02; N, 9.89.
1-(4-Acetylphenyl)-4-phenyl-5-(2-phenylethynyl)-1H-
1,2,3-triazole (4g): white solid; mp 138–140 °C. IR (KBr):
2215, 1680 cm–1. 1H NMR (300 MHz, CDCl3): d = 2.69 (s,
3 H), 7.41–7.55 (m, 8 H), 8.08 (d, J = 8.7 Hz, 2 H), 8.18 (d,
J = 9.0 Hz, 2 H), 8.28 (d, J = 7.8 Hz, 2 H). 13C NMR (75
MHz, CDCl3): d = 26.7 (CH3), 76.1 (C), 102.7 (C), 108.3
(C), 121.2 (C), 123.4 (CH), 126.6 (CH), 128.73 (CH),
128.77 (CH), 129.0 (CH), 129.5 (CH), 129.83 (C), 129.91
(CH), 131.5 (CH), 137.3 (C), 139.9 (C), 149.1 (C), 196.8
(C). EI–MS: m/z = 363 [M+], 335 [M – N2]+. Anal. Calcd for
C24H17N3O: C, 79.32; H, 4.72; N, 11.56. Found: C, 79.30; H,
4.69; N, 11.51.
1-(4-Acetylphenyl)-4-pentyl-5-(hept-1-ynyl)-1H-1,2,3-
triazole (4h): liquid. IR (KBr): 2235, 1689 cm–1. 1H NMR
(300 MHz, CDCl3): d = 0.88–0.93 (m, 6 H), 1.31–1.39 (m, 8
H), 1.57–1.64 (m, 2 H), 1.76–1.81 (m, 2 H), 2.49 (t, J = 6.8
Hz, 2 H), 2.67 (s, 3 H), 2.79 (t, J = 7.5 Hz, 2 H), 7.98 (d, J =
8.7 Hz, 2 H), 8.11 (d, J = 8.1 Hz, 2 H). 13C NMR (75 MHz,
CDCl3): d = 13.88 (CH3), 13.94 (CH3), 19.6 (CH2), 22.1
(CH2), 22.3 (CH2), 25.3 (CH2), 26.6 (CH3), 27.7 (CH2), 28.5
(CH2), 31.0 (CH2), 31.3 (CH2), 66.7 (C), 104.0 (C), 118.6
(C), 122.8 (CH), 129.3 (CH), 136.8 (C), 140.3 (C), 151.8
(C), 196.8 (C). EI–MS: m/z = 351 [M+], 323 [M – N2]+. Anal.
Calcd for C22H29N3O: C, 75.18; H, 8.32; N, 11.96. Found: C,
75.11; H, 8.33; N, 11.93.
1-(2-Methoxyphenyl)-4-(4-methoxyphenyl)-5-[2-(4-
methoxyphenyl)ethynyl]-1H-1,2,3-triazole (4i): white
solid; mp 96–98 °C. IR (KBr): 2217 cm–1. 1H NMR (300
MHz, CDCl3): d = 3.81 (s, 3 H), 3.84 (s, 3 H), 3.87 (s, 3 H),
6.84 (d, J = 8.7 Hz, 2 H), 7.02 (d, J = 8.7 Hz, 2 H), 7.12 (t,
J = 7.5 Hz, 2 H), 7.28 (d, J = 9.3 Hz, 2 H), 7.50 (d, J = 7.2
Hz, 2 H), 8.22 (d, J = 9.0 Hz, 2 H). 13C NMR (75 MHz,
CDCl3): d = 55.3 (CH3), 55.3 (CH3), 55.9 (CH3), 75.1 (C),
101.0 (C), 112.2 (CH), 113.8 (C), 114.0 (CH), 114.2 (CH),
118.9 (C), 120.6 (CH), 123.2 (C), 125.4 (C), 127.6 (CH),
128.3 (CH), 131.5 (CH), 133.0 (CH), 146.8 (C), 154.3 (C),
159.8 (C), 160.3 (C). EI–MS: m/z = 411 [M+], 383 [M – N2]+.
Anal. Calcd for C25H21N3O3: C, 72.98; H, 5.14; N, 10.21.
Found: C, 72.93; H, 5.10; N, 10.20.
1-(2-Methoxyphenyl)-4-phenyl-5-(2-phenylethynyl)-1H-
1,2,3-triazole (4j): white solid; mp 84–86 °C. IR (KBr):
2219 cm–1. 1H NMR (300 MHz, CDCl3): d = 3.83 (s, 3 H),
7.10–7.52 (m, 12 H), 8.30 (d, J = 8.4 Hz, 2 H). 13C NMR (75
MHz, CDCl3): d = 55.8 (CH3), 76.1 (C), 101.0 (C), 112.1
(CH), 119.4 (C), 120.6 (CH), 121.6 (C), 125.1 (C), 125.8
(CH), 126.3 (CH), 128.2 (CH), 128.5 (CH), 128.6 (CH),
129.3 (CH), 130.3 (C), 131.3 (CH), 131.7 (CH), 147.1 (C),
154.2 (C). EI–MS: m/z = 351 [M+], 323 [M – N2]+. Anal.
Calcd for C23H17N3O: C, 78.61; H, 4.88; N, 11.96. Found: C,
78.55; H, 4.91; N, 11.94.
1-(4-Chlorophenyl)-4-phenyl-5-(2-phenylethynyl)-1H-
1,2,3-triazole (4e): white solid; mp 95–97 °C. IR (KBr):
2219 cm–1. 1H NMR (300 MHz, CDCl3): d = 7.39–7.57 (m,
10 H), 7.85 (d, J = 8.1 Hz, 2 H), 8.26 (d, J = 8.4 Hz, 2 H). 13
C
NMR (75 MHz, CDCl3): d = 76.1 (C), 102.4 (C), 116.7 (C),
121.2 (C), 124.9 (CH), 126.5 (CH), 128.7 (CH), 128.7 (CH),
128.9 (CH), 129.5 (CH), 129.8 (CH), 129.9 (C), 131.5 (CH),
135.0 (C), 135.3 (C), 148.7 (C). EI–MS: m/z = 355 [M+], 327
[M – N2]+. Anal. Calcd for C22H14ClN3: C, 74.26; H, 3.97; N,
11.81. Found: C, 74.21; H, 3.96; N, 11.77.
(17) (a) Siemsen, P.; Livingston, R. C.; Diederich, F. Angew.
Chem. Int. Ed. 2000, 39, 2632. (b) Myers, A. G.; Goldberg,
S. D. Angew Chem. Int. Ed. 2000, 39, 2732.
1-(4-Acetylphenyl)-4-(4-methoxyphenyl)-5-[2-(4-
methoxyphenyl)ethynyl]-1H-1,2,3-triazole (4f): white
solid; mp 126–128 °C. IR (KBr): 2214, 1685 cm–1. 1H NMR
(300 MHz, CDCl3): d = 2.67 (s, 3 H), 3.84 (s, 3 H), 3.87 (s,
3 H), 6.91 (d, J = 8.4 Hz, 2 H), 7.03 (d, J = 8.4 Hz, 2 H), 7.43
(d, J = 8.1 Hz, 2 H), 8.06 (d, J = 8.4 Hz, 2 H), 8.16 (d, J = 8.1
Hz, 2 H), 8.20 (d, J = 8.1 Hz, 2 H). 13C NMR (75 MHz,
CDCl3): d = 26.7 (CH3), 55.3 (CH3), 55.4 (CH3), 75.2 (C),
102.7 (C), 113.2 (C), 114.1 (CH), 114.4 (CH), 116.0 (C),
122.5 (C), 123.2 (CH), 127.8 (CH), 129.4 (CH), 133.0 (CH),
(18) Crystal data: C22H15N3, MW = 321.37, T = 294(2) K, l =
0.71073 Å, monoclinic, space group P21/c, a = 7.6038(2) Å,
b = 18.6814(6) Å, c = 12.1815(4) Å, a = 90.00°, b = 91.356
(2)°, g = 90.00°, V = 1729.89(9) Å3, Z = 4, D = 1.234 g/cm3,
m = 0.074 mm–1, F(000) = 672.0. Crystallographic data
(excluding structure factors) for the structure reported in this
paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication
CCDC-626008.
Synlett 2007, No. 2, 278–282 © Thieme Stuttgart · New York

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