Aryne click chemistry: Synthesis of oxadisilole fused benzotriazoles or naphthotriazoles from arynes and azides

Article abstract of DOI:10.1016/j.tet.2010.12.039

The oxadisilole fused benzotriazoles or naphthotriazole derivatives have been synthesized by 1,3-dipolar cycloaddition of various azides with arynes generated in situ from benzobisoxadisilole or 2,3-naphthoxadisilole in good yields under mild conditions.

Full text of DOI:10.1016/j.tet.2010.12.039

Tetrahedron 67 (2011) 856e859
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Aryne click chemistry: synthesis of oxadisilole fused benzotriazoles or
naphthotriazoles from arynes and azides
*
Yibei Lin, Yali Chen , Xuyan Ma, Di Xu, Weiguo Cao, Jie Chen
Department of Chemistry, Shanghai University, Shanghai 200444, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 6 October 2010
Received in revised form 3 December 2010
Accepted 14 December 2010
Available online 17 December 2010
The oxadisilole fused benzotriazoles or naphthotriazole derivatives have been synthesized by 1,3-dipolar
cycloaddition of various azides with arynes generated in situ from benzobisoxadisilole or 2,3-naph-
thoxadisilole in good yields under mild conditions.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
1,3-Dipolar cycloaddition
Azide
Aryne
Oxadisilole fused benzotriazole
Naphthotriazole
1. Introduction
promising extension of the current click chemistry. Herein, we de-
scribe the 1,3-dipolar cycloaddition reactions of azides with arynes
The Cu-catalyzed [3þ2] cycloaddition between terminal alkynes
and azides,1 termed ‘click’ chemistry,2 has been extensively studied
and applied to several areas of chemistry. Such chemistry included
materials science,3 chemical biology,4 and medicinal chemistry.5
Recently, Larock et al.6a reported the benzyne click chemistry,
which involved the reaction of organic azide with benzyne, gener-
ated from o-(trimethylsilyl)aryl triflates to give the corresponding
1H-benzo[d][1,2,3]triazoles (hereafter referred as benzotriazoles).6
Benzotrizole derivatives are important heterocyclic compounds.
They play important roles as structural and functional units in many
biological active compounds, natural products, and useful syn-
thons.7 Aryne is an important intermediate and synthon in organic
synthesis.8 Recently, we are interested in the chemistry of arynes
generated from benzobisoxadisilole, benzotrisoxadisilole, and 2,3-
naphthoxadisilole under very mild conditions. We found that ben-
zobisoxadisilole can serve as the synthetic equivalent of benzdiyne.
Their applications to the synthesis of functional acenes and benzo-
quinones have also been reported.9 The chemistry was further
extended to the synthesis of oxadisilole fused benzo[d]isoxazoline
and naphtho[2,3-d]isoxazoline derivatives by 1,3-dipolar cyclo-
addition reaction of nitrones with arynes.10 With this motif in mind,
we envisioned [3þ2] annulation of arynes by azides could be a very
generated in situ frombenzobisoxadisiloleor 2,3-naphthoxadisilole,
as a new aryne click chemistry.
2. Results and discussion
The synthesis of the oxadisilole fused benzotriazole derivatives
5aej or the naphthotriazole derivatives 9aee are outlined in
Schemes 1 and 2. Arynes 3 and 8 were generated from benzobi-
soxadisilole 1 and 2,3-naphthoxadisilole 6, respectively, through
our previously reported phenyliodination fluoride induced desi-
lylation protocol.9a,b Trapping benzyne 3 and naphthyne 8 at room
temperature with azides 4aej via 1,3-dipolar cycloaddition re-
actions afforded the oxadisilole fused benzotriazole derivatives
Si
Si
Si
Si
Si
Si
Si(OH)Me2
I(Ph)OTf
Si
Si
PhI(OAc)2, TfOH
CH2Cl2, 0 C to rt
CsF
O
O
O
O
i-Pr2NH, rt
1
2
3
X
X
X
X
or
4a-e
a, f: X = OCH3
b, g: X = CH3
c, h: X = H
Si
Si
N
N
N
N
N3 4f-j
N3
or
N
O
O
N
Si
Si
d, i: X = Cl
e, j: X = NO2
5f-j
5a-e
* Corresponding author. Tel./fax: þ8621 66132797; e-mail address: ylchen@
Scheme 1.
staff.shu.edu.cn (Y. Chen).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.12.039

Y. Lin et al. / Tetrahedron 67 (2011) 856e859
857
Table 3
Si
Si
Si(OH)Me2
I(Ph)OTf
PhI(OAc)2, TfOH
CsF
Cycloaddition of azides 4aej with benzyne 3 generated from benzobisoxadisilole
1 at room temperature
O
i-Pr2NH, rt
CH2Cl2, 0
to rt
Yielda (%)
7
6
8
Entry
Azide
X
Product
X
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4e
4f
4g
4h
4i
OCH3
CH3
H
5a
5b
5c
5d
5e
5f
5g
5h
5i
56
63
67
80
87
61
75
78
92
74
X
a: X = OCH3
b: X = CH3
c: X = H
d: X = Cl
e: X = NO2
Cl
N
N
N
4a-e
N3
NO2
OCH3
CH3
H
Cl
NO2
9a-e
Scheme 2.
10
4j
5j
a
Isolated yields.
5aej and naphthotriazole derivatives 9aee in good yields. Benzyl
azides 4aee or aryl azides 4fej were prepared according to the
literature procedures.11
56e92% yields (Scheme 1 and Table 3, entries 1e10). As shown from
the chemical yields, this 1,3-dipolar cycloaddition of azides 4 to
benzyne 3 is rather sensitive in the electronic nature (X¼OCH3, CH3,
H, Cl, NO2) of the substituents on the benzyl or aryl azides. The
results revealed that electron rich azides gave lower yields than
electron deficient ones. Strengthening the electron donating of
substituent X, the yield was decreased and the reactivity was
weakened. On the contrary, strengthening the electron withdraw-
ing of substituent X, the yield was increased and the reactivity was
improved (Table 3). It should be pointed out that the lower yield of
product 5j than 5i was observed in repeated experiments many
times, may be due to a little denitrogenation competing reaction
pathways of aryl azide to occur in 1,3-dipolar cycloaddition when
the substituent is a so strong electron withdrawing group (X¼NO2).
Our attention was then turned to the 1,3-dipolar cycloaddition
reactions of naphthyne 8 generated in situ from the 2,3-naph-
thoxadisilole 6 with benzyl azides 4aee. To our delight, benzyl
azides 4aee successfully participated in the cycloaddition reaction
with naphthyne 8 at room temperature to afford the corresponding
naphthotriazole derivatives 9aee in moderate yields (Scheme 2
and Table 4, entries 1e5). The structures of all the cycloadducts,
5aej and 9aee, were established by 1H and 13C NMR, MS, IR, ele-
mental analysis, and HRMS.
Our investigation started with the reaction of phenyl azide 4h
and oxadisilole fused benzyne 3 generated in situ from benzobi-
soxadisilole. Phenyliodination of 1 with a 1.5:3 mixture of phe-
nyliodium diacetate (PhI(OAc)2) and trifluoromethanesulfonic acid
(TfOH) took place readily at room temperature in dichloromethane
(Scheme 1). Without isolation of the ring-opened iodination in-
termediate 2, benzyne 3 could be generated in situ upon treatment
with cesium fluoride (CsF). Trapping experiments were carried out
with 10 equiv of phenyl azide 4h (X¼H) at room temperature to
afford 52% isolated yields of the oxadisilole fused benzotriazole
derivative 5h in this three-step reaction (Scheme 1 and Table 1,
entry 3). When acetonitrile was used as the solvent with CsF as the
fluoride source, the yield of adduct 5h dropped to 36%. At 80 ꢀC, the
yield was slightly increased to 39% (Table 1, entries 1 and 2). We
tried tetrabutylammonium fluoride (TBAF) or CsF/18-crown-6 as
the fluoride source in CH2Cl2, the isolated yields of 5h were 45% and
50%, respectively (Table 1, entries 4 and 5).
Table 1
Cycloaddition of phenyl azide 4h (10 equiv) with benzyne 3 generated from ben-
zobisoxadisilole 1 in different fluoride sources and solvents
Entry
Fluoride source
Solvent
T/ꢀC
Yielda of 5h (%)
1
2
3
4
5
CsF
CsF
CsF
TBAF
CH3CN
CH3CN
CH2Cl2
CH2Cl2
CH2Cl2
rt
80
rt
rt
rt
36
39
52
45
50
Table 4
Cycloaddition of azides 4aee with 2,3-naphthyne 8 generated from 2,3-naphthox-
adisilole 6 at room temperature
CsF/18-crown-6
Entry
Azide
X
Product
Yielda (%)
a
Isolated yields.
1
2
3
4
5
4a
4b
4c
4d
4e
OCH3
CH3
H
Cl
NO2
9a
9b
9c
9d
9e
31
38
40
42
48
With these preliminary results, we varied the amount of phenyl
azide (4h) used. When molar ratio of benzobisoxadisilole 1 to
phenyl azide 4h was 4:1, we find that the yield of the oxadisilole
fused benzotriazole derivative (5h) could be improved to 78%
(Table 2, entry 6). We also tried other molar ratios, as shown in
Table 2, the yields of 5h have not been improved.
a
Isolated yields.
In summary, a simple and efficient synthetic method of 1,3-di-
polar cycloaddition of azides 4aej with arynes 3 or 8 generated in
situ from benzobisoxadisilole 1 or 2,3-naphthoxadisilole 6 has been
developed. The experimental results showed that the reaction was
affected by electronic effects, wherein the presence of electron
withdrawing groups show high reactivity compared to that of
electron donating groups. The advantage of the method is not only
good yields but also very mild conditions. These reactions could
offer great opportunities for the synthesis of important heterocyclic
compounds.
Table 2
Cycloaddition of phenyl azide 4h with benzyne 3 generated from benzobisox-
adisilole 1 at room temperature in CH2Cl2
Entry
Molar ratio of 1/4h
Yielda of 5h (%)
1
2
3
4
5
6
1:1.2
1:3
1:5
1:10
2:1
4:1
53
51
55
52
56
78
a
3. Experimental
3.1. General
Isolated yields.
We further studied the 1,3-dipolar cycloaddition reaction of
benzyne 3 generated in situ from the benzobisoxadisilole 1 with
benzyl azides 4aee or aryl azides 4fej at room temperature. The
oxadisilole fused benzotriazole derivatives 5aej were formed in
IR spectra were recorded on
a Bruker spectrometer and
expressed in cmꢁ1 (KBr disc). NMR spectra were measured at

858
Y. Lin et al. / Tetrahedron 67 (2011) 856e859
500 MHz for 1H and 125 MHz for 13C by Bruker DRX-500 NMR
spectrometer. Chemical shifts of 1H NMR were expressed in parts
per million downfield from tetramethylsilane with reference to
8.23 (d, J¼1.0 Hz, 1H); 13C NMR (125 MHz, CDCl3)
d 1.2, 1.3, 52.1,
112.3, 123.1, 127.6, 128.5, 129.0, 134.1, 134.9, 142.3, 146.9, 147.6; IR
(KBr) 3064, 2959, 2898, 1601, 1497, 1454, 1251, 1100, 1073, 923,
847 cmꢁ1; MS m/z (%) (EI): 339 (Mþ, 14), 310 (52), 296 (39), 91
(100); HRMS: m/z [M]þ calcd for C17H21N3OSi2: 339.1223; found
339.1229.
internal residual CHCl3
(d
¼7.26) in CDCl3. Chemical shifts of 13C
NMR were expressed in parts per million downfield from CDCl3 as
an internal standard (
d¼77.17) in CDCl3. Coupling constants (J) are
quoted in hertz. Low-resolution mass spectra were obtained on an
Agilent LC/MSD SL spectrometer in EI mode and reported as m/z.
High-resolution mass spectra (HRMS) were recorded on a Waters
Micromass GCT instrument. Elemental analyses were measured on
the Elemental Vario EL III. Melting points were determined on
a WRS-1 digital melting point apparatus and are uncorrected. All
reagents and solvents were obtained from commercial sources and
used without purification, unless indicated otherwise. All non-
aqueous reactions were carried out in oven-dried glassware under
a slight positive pressure of nitrogen unless otherwise noted. Sol-
vents were reagent grade and purified by standard techniques: THF
was distilled from Na/benzophenone; CH2Cl2 was distilled from
CaH2. Crude products were purified by column chromatography on
silica gel (G or GF254). PE indicates petroleum ether (bp 60e80 ꢀC).
3.2.4. 1-(4-Chlorobenzyl)-5,6-oxadisilole fused benzotriazole (5d). As
a white solid; mp 132e133 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.37 (s,
6H), 0.41 (s, 6H), 5.83 (s, 2H), 7.21 (d, J¼8.5 Hz, 2H), 7.31 (d,
J¼8.5 Hz, 2H), 7.54 (d, J¼1.0 Hz, 1H), 8.24 (d, J¼1.0 Hz, 1H); 13C NMR
(125 MHz, CDCl3)
d 1.22, 1.24, 51.2, 112.0, 123.1, 128.9, 129.1, 133.4,
133.9, 134.3, 142.5, 147.2, 147.5; IR (KBr) 3049, 2958, 2896, 1599,
1492, 1456, 1249, 1131, 1074, 942, 845 cmꢁ1; MS m/z (%) (EI): 373
(Mþ, 15), 344 (23), 330 (35), 310 (34), 125 (100); HRMS: m/z [M]þ
calcd for C17H20N3OClSi2: 373.0833; found 373.0837.
3.2.5. 1-(4-Nitrobenzyl)-5,6-oxadisilole fused benzotriazole (5e). As
a white solid; mp 172e173 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.37 (s,
6H), 0.42 (s, 6H), 5.97 (s, 2H), 7.40 (d, J¼9.0 Hz, 2H), 7.54 (d,
J¼1.5 Hz, 1H), 8.20 (d, J¼9.0 Hz, 2H), 8.27 (d, J¼1.5 Hz, 1H); 13C NMR
3.2. General procedure for the preparation of oxadisilole
fused benzotriazole derivatives 5aej and naphthotriazole
derivatives 9aee
(125 MHz, CDCl3) d 1.2, 1.3, 50.9, 111.6, 123.3, 124.3, 128.2, 134.0,
142.1, 143.0, 147.6, 147.8, 147.9; IR (KBr) 3080, 2959, 2901, 1608,
1520, 1456, 1252, 1130, 1072, 934, 849 cmꢁ1; MS m/z (%) (EI): 384
(Mþ, 52), 356 (76), 341 (100), 310 (23), 136 (75); HRMS: m/z [M]þ
calcd for C17H20N4O3Si2: 384.1074; found 384.1070.
Trifluoromethanesulfonic acid (0.27 mL, 3.0 mmol) was added
with a syringe to a stirred solution of phenyliodium diacetate
(493 mg, 1.5 mmol in 10 mL of CH2Cl2) at 0 ꢀC. The mixture was
stirred under N2 for 1 h at 0 ꢀC and for 2 h at room temperature. The
clear yellow solution was cooled again to 0 ꢀC followed by dropwise
addition of a cold (0 ꢀC) solution of the benzobisoxadisilole 1 (or 2,3-
naphthoxadisilole 6) (1.0 mmol in 5 mL of CH2Cl2). The mixture was
stirred for 0.5 h at 0 ꢀC and warmed up to room temperature. After
benzobisoxadisilole 1 (or 2,3-naphthoxadisilole 6) disappeared
(monitored by TLC), diisopropylamine (0.35 mL, 2.5 mmol) and
azides 4 (0.25 mmol) were added followed by CsF (380 mg,
2.5 mmol). The mixture was stirred under N2 for 5 h at room tem-
perature. The organic solvent was removed under reduced pressure.
The crude product was purified by column chromatography on silica
gel using a gradient of 2e5% EtOAc in petroleum ether (60e80 ꢀC) as
eluent to afford cycloadducts 5aej and 9aee.
3.2.6. 1-(4-Methoxylphenyl)-5,6-oxadisilole fused benzotriazole (5f).
As a white solid; mp 118e119 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.40 (s,
6H), 0.44 (s, 6H), 3.92 (s, 3H), 7.14 (d, J¼8.5 Hz, 2H), 7.66 (d, J¼8.5 Hz,
2H), 7.81 (d, J¼1.5 Hz, 1H), 8.30 (d, J¼1.5 Hz,1H); 13C NMR (125 MHz,
CDCl3)
d 1.16, 1.20, 55.5, 112.8, 114.9, 123.0, 124.7, 129.8, 133.8, 142.6,
147.5, 159.8; IR (KBr) 3083, 2958, 1608, 1515, 1462, 1257, 1110, 1081,
938, 850 cmꢁ1; MS m/z (%) (EI):355 (Mþ, 4), 312 (100), 296 (7), 281
(2), 121 (2); HRMS: m/z [M]þ calcd for C17H21N3O2Si2: 355.1172;
found 355.1169.
3.2.7. 1-(4-Methylphenyl)-5,6-oxadisilole fused benzotriazole (5g). As
a white solid; mp 135e136 ꢀC; 1H NMR (500 MHz, CDCl3))
d 0.40 (s,
6H), 0.44 (s, 6H), 2.49 (s, 3H), 7.44 (d, J¼8.0 Hz, 2H), 7.65 (d, J¼8.0 Hz,
2H), 7.85 (d, J¼1.0 Hz, 1H), 8.30 (d, J¼1.0 Hz,1H); 13C NMR (125 MHz,
CDCl3)
d 1.2, 1.3, 21.2, 113.0, 123.1, 123.2, 130.4, 133.6, 134.5, 138.8,
3.2.1. 1-(4-Methoxylbenzyl)-5,6-oxadisilole fused benzotriazole
142.7,147.68,147.74; IR (KBr) 2957,1600,1516, 1443, 1250, 1112, 1083,
930, 845 cmꢁ1; MS m/z (%) (EI): 339 (Mþ, 4), 296 (100), 105 (4);
HRMS: m/z [M]þ calcd for C17H21N3OSi2: 339.1223; found 339.1227.
(5a). As a white solid; mp 111e112 ꢀC; 1H NMR (500 MHz, CDCl3)
d
0.37 (s, 6H), 0.40 (s, 6H), 3.78 (s, 3H), 5.80 (s, 2H), 6.86 (d, J¼8.5 Hz,
2H), 7.25 (d, J¼8.5 Hz, 2H), 7.55 (d, J¼1.0 Hz, 1H), 8.22 (d, J¼1.0 Hz,
1H); 13C NMR (125 MHz, CDCl3)
1.0, 1.1, 51.3, 55.0, 112.4, 114.1,
d
3.2.8. 1-Phenyl-5,6-oxadisilole fused benzotriazole (5h). As an or-
122.7, 126.8, 128.9, 133.8, 142.0, 146.5, 147.4, 159.4; IR (KBr) 3040,
2959, 2899, 1611, 1513, 1457, 1245, 1127, 1077, 932, 847 cmꢁ1; MS m/
z (%) (EI): 369 (Mþ, 33), 340 (55), 326 (89), 310 (57), 121 (100);
HRMS: m/z [M]þ calcd for C18H23N3O2Si2: 369.1329; found
369.1330.
ange solid; mp 139e140 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.42 (s,
6H), 0.45 (s, 6H), 7.52e7.56 (m, 1H), 7.63e7.66 (m, 2H), 7.79e7.81
(m, 2H), 7.89e7.90 (m, 1H), 8.32 (s, 1H); 13C NMR (125 MHz, CDCl3)
d
1.26, 1.29, 112.9, 123.1, 123.3, 128.8, 129.9, 133.5, 137.0, 143.0, 147.9,
148.0; IR (KBr) 3054, 2958, 1597, 1501, 1436, 1252, 1171, 1084, 934,
847 cmꢁ1; MS m/z (%) (EI): 325 (Mþ, 3), 282 (100), 77 (4); HRMS: m/
z [M]þ calcd for C16H19N3OSi2: 325.1067; found 325.1065.
3.2.2. 1-(4-Methylbenzyl)-5,6-oxadisilole fused benzotriazole (5b). As
a white solid; mp 140e141 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.37 (s,
6H), 0.40 (s, 6H), 2.32 (s, 3H), 5.82 (s, 2H), 7.14 (d, J¼8.0 Hz, 2H), 7.19
3.2.9. 1-(4-Chlorophenyl)-5,6-oxadisilole fused benzotriazole (5i). As
(d, J¼8.0 Hz, 2H), 7.55 (d, J¼1.5 Hz, 1H), 8.22 (d, J¼1.5 Hz, 1H); 13C
a white solid; mp 159e160 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.42 (s,
NMR (125 MHz, CDCl3)
d
1.17, 1.21, 21.0, 51.7, 112.4, 122.9, 127.5,
6H), 0.45 (s, 6H), 7.62 (d, J¼8.5 Hz, 2H), 7.75 (d, J¼8.5 Hz, 2H), 7.84 (d,
129.5, 131.9, 134.0, 138.1, 142.1, 146.7, 147.5; IR (KBr) 3034, 2958,
2937, 1600, 1516, 1454, 1249, 1130, 1077, 943, 843 cmꢁ1; MS m/z (%)
(EI): 353 (Mþ, 18), 324 (43), 310 (96), 105 (100); HRMS: m/z [M]þ
calcd for C18H23N3OSi2: 353.1380; found 353.1382.
J¼1.5 Hz,1H), 8.32 (d, J¼1.5 Hz,1H); 13C NMR (125 MHz, CDCl3)
d 1.28,
1.30,112.6,123.4,124.2,130.2,133.4,134.5,135.6,143.3,147.9,148.4; IR
(KBr) 3058, 2956, 1594, 1497, 1441, 1251, 1176, 1085, 928, 845 cmꢁ1
;
MS m/z (%)(EI): 359 (Mþ, 4), 316 (100), 296 (8), 281 (9),111 (3); HRMS:
m/z [M]þ calcd for C16H18N3OClSi2: 359.0677; found 359.0674.
3.2.3. 1-Benzyl-5,6-oxadisilole fused benzotriazole (5c). As a white
solid; mp 147e148 ꢀC; 1H NMR (500 MHz, CDCl3)
0.41 (s, 6H), 5.87 (s, 2H), 7.29e7.35 (m, 5H), 7.54 (d, J¼1.0 Hz, 1H),
d
0.36 (s, 6H),
3.2.10. 1-(4-Nitrophenyl)-5,6-oxadisilole fused benzotriazole (5j). As
a white solid; mp 237e239 ꢀC; 1H NMR (500 MHz, CDCl3)
d 0.45 (s,

Y. Lin et al. / Tetrahedron 67 (2011) 856e859
859
6H), 0.46 (s, 6H), 7.95 (d, J¼1.0 Hz, 1H), 8.08 (d, J¼9.0 Hz, 2H), 8.36
(d, J¼1.0 Hz, 1H), 8.54 (d, J¼9.0 Hz, 2H); 13C NMR (125 MHz, CDCl3)
229 (44), 136 (94); HRMS: m/z [M]þ calcd for C17H12N4O2:
304.0960; found 304.0958.
d
1.3, 112.6,122.6,123.8, 125.7, 132.9, 142.1,144.2,146.9, 148.3,149.6;
IR (KBr) 3085, 2962, 1592, 1520, 1502, 1246, 1112, 1083, 939,
850 cmꢁ1; MS m/z (%) (EI): 370 (Mþ, 8), 327 (100), 296 (72), 281
(95), 122 (2); HRMS: m/z [M]þ calcd for C16H18N4O3Si2: 370.0917;
found 370.0922.
Acknowledgements
Financial support from the National Natural Science Foundation
of China (No. 20872086), the Project of Shanghai Municipal Edu-
cation Commission (Nos. 09YZ19 and J50102).
3.2.11. 1-(4-Methoxybenzyl)naphthotriazole (9a). As a brown solid;
mp 145e146 ꢀC; 1H NMR (500 MHz, CDCl3)
d 3.71 (s, 3H), 5.82 (s,
References and notes
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7.74 (s, 1H), 7.82 (d, J¼8.5 Hz,1H), 7.96 (d, J¼8.5 Hz,1H), 8.57 (s,1H);
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13C NMR (125 MHz, CDCl3)
d 51.9, 55.3, 105.6, 114.3, 117.9, 124.66,
126.5, 126.9, 128.0, 129.0, 129.3, 130.5, 131.4, 132.8, 145.5, 159.6; IR
(KBr) 3043, 2963, 2934, 1610, 1512, 1461, 1246, 1140, 1087, 946,
853 cmꢁ1; MS m/z (%) (EI): 289 (Mþ, 100), 260 (53), 240 (91), 230
(44), 121 (97). Anal. Calcd for C18H15N3O: C, 74.72; H, 5.23; N, 14.52.
Found: C, 74.45; H, 5.38; N, 13.93.
3.2.12. 1-(4-Methylbenzyl)naphthatriazole (9b). As a yellow solid;
mp 156e157 ꢀC; 1H NMR (500 MHz, CDCl3)
d 2.29 (s, 3H), 5.87 (s,
2H), 7.11 (d, J¼8.0 Hz, 2H), 7.20 (d, J¼8.0 Hz, 2H), 7.37e7.44 (m,
2H), 7.75 (s, 1H), 7.83 (d, J¼8.5 Hz, 1H), 7.98 (d, J¼8.5 Hz, 1H), 8.59
(s, 1H); 13C NMR (125 MHz, CDCl3)
d 21.1, 52.1, 105.5, 117.9, 124.6,
126.5, 127.5, 127.9, 129.3, 129.6, 130.5, 131.5, 131.9, 132.8, 138.2,
145.5; IR (KBr) 3046, 2972, 2851, 1614, 1512, 1441, 1257, 1141,
1093, 950, 855 cmꢁ1; MS m/z (%) (EI): 273 (Mþ, 100), 244 (89),
230 (90), 105 (96); HRMS: m/z [M]þ calcd for C18H15N3: 273.1266;
found 273.1265.
3.2.13. 1-Benzylnaphthatriazole (9c). As a white solid; mp 182e
183 ꢀC; 1H NMR (500 MHz, CDCl3)
d 5.94 (s, 2H), 7.32 (s, 5H),
7.40e7.47 (m, 2H), 7.77 (s, 1H), 7.86 (d, J¼8.0 Hz, 1H), 8.01 (d,
J¼8.0 Hz, 1H), 8.62 (s, 1H); 13C NMR (125 MHz, CDCl3)
d 52.3, 105.5,
118.1,124.8,126.6,127.6,128.0,128.5,129.1,129.4,130.6,131.6,132.9,
135.0, 145.5; IR (KBr) 3059, 2961, 2928, 1629, 1497, 1453, 1258, 1103,
1072 cmꢁ1; MS m/z (%) (EI): 259 (Mþ, 54), 230 (82), 91 (100). Anal.
Calcd for C17H13N3: C, 78.74; H, 5.05; N, 16.20. Found: C, 78.35; H,
5.13; N, 16.01.
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Gilchrist, T. L. In Supplement C2, The Chemistry of Functional Groups; Patai, S.,
Rappoport, Z., Eds.; Wiley: Chichester, UK, 1983; pp 383e419; (d) Cobas, A.;
Diaz, M. T.; Escudero, S.; Prez, D.; Guitian, E.; Castedo, L. In Current Trends in
Organic Synthesis; Scolastico, C., Nicotra, F., Eds.; Plenum: 1999; pp 307e314;
(e) Wank, H. H.; Sand, W.; Winkler, M. Angew. Chem., Int. Ed. 2003, 42,
502e528; (f) Pellisier, H.; Santelli, M. Tetrahedron 2003, 59, 701e730; (g) Je-
ganmohan, M.; Cheng, C. H. Chem. Commun. 2006, 2455e2456; (h) Yoshida, H.;
Fukushima, H.; Ohshita, J.; Kunai, A. J. Am. Chem. Soc. 2006, 128, 11040e11041;
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M.; Stoltz, B. M. J. Am. Chem. Soc. 2008, 130, 17270e17271.
3.2.14. 1-(4-Chlorobenzyl) naphthatriazole (9d). As a white solid;
mp 158e159 ꢀC; 1H NMR (500 MHz, CDCl3)
d 5.89 (s, 2H), 7.27e7.29
(m, 4H), 7.40e7.47 (m, 2H), 7.74 (s, 1H), 7.86 (d, J¼8.5 Hz, 1H), 8.01
(d, J¼8.5 Hz, 1H), 8.62 (s, 1H); 13C NMR (125 MHz, CDCl3)
d 51.5,
105.3, 118.2, 124.9, 126.8, 127.9 128.9, 129.3, 129.4, 130.6, 131.4,
133.0, 133.4, 134.4, 145.4; IR (KBr) 3039, 2965, 2937, 1613, 1489,
1470,1257,1147, 1085, 932, 854 cmꢁ1; MS m/z (%) (EI): 293 (Mþ, 54),
264 (43), 230 (52),125 (100). Anal. Calcd for C17H12ClN3: C, 69.51; H,
4.12; N, 14.30. Found: C, 69.30; H, 4.17; N, 14.15.
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43, 2259e2262; (b) Chen, Y. L.; Sun, J. Q.; Wei, X.; Wong, W. Y.; Lee, A. W. M.
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Wong, M. S.; Lee, A. W. M. J. Org. Chem. 2006, 71, 3512e3517; (d) Chen, Y. L.; Lee,
M. H.; Wong, W. Y.; Lee, A. W. M. Synlett 2006, 2510e2512; (e) Chen, Y. L.;
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Tetrahedron 2010, 66, 578e582.
3.2.15. 1-(4-Nitrobenzyl) naphthatriazole (9e). As a yellow solid;
mp 188e190 ꢀC; 1H NMR (500 MHz, CDCl3)
d 6.04 (s, 2H), 7.41e7.48
(m, 4H), 7.76 (s, 1H), 7.87 (d, J¼8.5 Hz, 1H), 8.03 (d, J¼8.5 Hz, 1H),
8.16 (d, J¼8.5 Hz, 2H), 8.65 (s, 1H); 13C NMR (125 MHz, CDCl3)
d 51.3,
104.9, 118.6, 124.3,125.1, 127.1, 127.9, 128.3, 129.5, 130.8, 131.4, 133.2,
142.1, 145.4, 148.0; IR (KBr) 3102, 2967, 2940,1605, 1526,1443, 1257,
1108, 1090, 941, 856 cmꢁ1; MS m/z (%) (EI): 304 (Mþ, 100), 275 (21),
11. Kamalra, V. R.; Senthil, J. S.; Kannan, P. J. Mol. Struct. 2008, 892, 210e215.