Synthesis of 1,2,4-triazol-5-ylidenes and their interaction with acetonitrile and chalcogens

Article abstract of DOI:10.1021/jo034234n

Two new, more convenient methods for the synthesis of 1,2,4-triazol-5-ylidenes are described. Four new 1,2,4-triazol-5-ylidenes have been prepared using these methods: 1-(1-adamantyl)-3,4-diphenyl-1,2,4-triazol-5-ylidene (2a), 1-(1-adamantyl)-3-phenyl-4-(

Full text of DOI:10.1021/jo034234n

et al.8 demonstrated that a liquid NH3/THF solvent
system is very effective for the NaH deprotonation of
imidazolium salts at relative low temperatures. A com-
pletely new synthetic route to stable nucleophilic car-
benes was developed by Kuhn et al.,9 namely the reduc-
tion of imidazole-2(3)-thiones with potassium in refluxing
THF. The range of stable nucleophilic carbenes has also
expanded significantly, not only in terms of the elabora-
tion of substituents and the development of multidentate
systems but also from the standpoint of new structure
types.10 For example, Alder et al.7 have shown that it is
possible to isolate acyclic nucleophilic carbenes, and
Enders et al.11 reported the preparation of 1,2,4-triazol-
5-ylidenes by deprotonation of the corresponding triazo-
lium salts with NaOMe in MeOH, followed by the
elimination of MeOH under reduced pressure (0.1 mbar)
at 80 °C. In the present contribution, we describe (i) two
new, more convenient approaches to the synthesis of
1,2,4-triazol-5-ylidenes, (ii) the X-ray crystal structure of
a representative 1,2,4-triazol-5-ylidene along with that
of the precursor triazolium salt, (iii) a C-H insertion
reactions of a 1,2,4-triazol-5-ylidene and the related
triazolium salt, and (iv) the reactions of 1,2,4-triazol-5-
ylidenes with sulfur and selenium.
The triazolium perchlorates 1a -d were prepared by a
two-stage procedure. First, the triazolium bromide salts
were prepared by heating the 3,4-diaryl-1,2,4-triazols
with 1-bromoadamantane in acetic acid. In the second
stage, anion exchange to form 1a -d was effected by
treatment of the bromide salts with aqueous NaClO4. In
general, the intermediate triazolium bromides were
converted directly into the corresponding perchlorate
salts. However, in one case, the crystals of the triazolium
bromide (1e) were prepared and found to be suitable for
X-ray crystallographic study (see later). Two procedures,
A and B, were employed for the preparation of the 1,2,4-
triazol-5-ylidenes 2a -d . In method A, a suspension of
the triazolium perchlorate (1a -d ) was treated with an
equimolar quantity of potassium tert-butoxide in benzene.
The replacement of perchlorate by tert-butoxide anions
in the first stage of this procedure occurs quantitatively
due to very low solubility of KClO4 in aromatic solvents,
thus minimizing the potential danger of explosion. In
method B, a solution of the triazolium perchlorate in
acetonitrile was allowed to react with a 55% dispersion
of sodium hydride in mineral oil, the progress of the
Syn th esis of 1,2,4-Tr ia zol-5-ylid en es a n d
Th eir In ter a ction w ith Aceton itr ile a n d
Ch a lcogen s
Nikolai I. Korotkikh,*,† Gennady F. Rayenko,†
Oles P. Shvaika,† Tatyana M. Pekhtereva,†
Alan H. Cowley,*,‡ J amie N. J ones,‡ and
Charles L. B.Macdonald‡
The L. M. Litvinenko Institute of Physical Organic and
Coal Chemistry, Ukrainian Academy of Sciences,
70. R, Luxemburg Donetsk, 83114, Ukraine, and
Department of Chemistry & Biochemistry,
The University of Texas at Austin, 1 University
Station A5300, Austin, Texas 78712-0165
cowley@mail.utexas.edu
Received February 21, 2003
Abstr a ct: Two new, more convenient methods for the syn-
thesis of 1,2,4-triazol-5-ylidenes are described. Four new
1,2,4-triazol-5-ylidenes have been prepared using these
methods: 1-(1-adamantyl)-3,4-diphenyl-1,2,4-triazol-5-ylidene
(2a ), 1-(1-adamantyl)-3-phenyl-4-(p-bromophenyl)-1,2,4-tri-
azol-5-ylidene (2b), 1-(1-adamantyl)-3-phenyl-4-(R-naphthyl)-
1,2,4-triazol-5-ylidene (2c), and 1-(1-adamantyl)-3,4-di(p-
bromophenyl)-1,2,4-triazol-5-ylidene (2d ). The X-ray crystal
structures of 2d and the precursor salt 1-(1-adamantyl)-3,4-
di(p-bromophenyl)-1,2,4-triazolium bromide (1e) are de-
scribed. Compound 2a reacts with CH3CN via C-H insertion
to form 1-(1-adamantyl)-3,4-diphenyl-5-cyanomethyl-5H-
1,2,4-triazoline (3), and 2a and 2d react with elemental
sulfur and elemental selenium, respectively, to form the
corresponding thione (4) and selenone (5).
Following the postulation of nucleophilic heteroaro-
matic carbenes by Breslow1 and pioneering experimental
work on imidazol-2-ylidenes by Wanzlick and co-work-
ers,2 over two decades were to elapse before Arduengo et
al.3 reported the isolation and structural characterization
of a stable nucleophilic carbene. The synthetic route
employed by Arduengo et al. involved the deprotonation
of an imidazolium chloride with sodium or potassium
hydride in the presence of either KO-t-Bu or the DMSO
anion.4a-c Subsequently, other bases such as n-BuLi,5
KN(SiMe3)2,6 and LDA7 have been used, and Herrmann
† Ukrainian Academy of Sciences.
‡ The University of Texas at Austin.
(1) (a) Breslow, R. J . Am. Chem. Soc. 1957, 79, 1762. (b) Breslow.
R. J . Am. Chem. Soc. 1958, 80, 3719.
(2) Wanzlick, H.-W.; Scho¨nherr, H. Liebigs Ann. Chem. 1970, 731,
176; Scho¨nherr, H. J .; Wanzlick, H.-W. Chem. Ber. 1970, 103, 1037.
(3) Arduengo, A. J ., III; Harlow, R. L.; Kline, M. J . Am. Chem. Soc.
1991, 113, 361.
(4) (a) Arduengo, A. J ., III; Dias, H. V. R.; Harlow, R. L.; Kline, M.
J . Am. Chem. Soc. 1992, 114, 5530. (b) Arduengo, A. J ., III; Goerlich,
J . R.; Krafczyk, R.; Marshall, W. J . Angew. Chem., Int. Ed. Engl. 1998,
37, 1963. (c) Arduengo, A. J ., III; Krafczyk, R.; Schmutzler R.; Craig,
H. A.; Goerlich, J . R.; Marshall, W. J .; Unverzagt, M. Tetrahedron 1999,
55, 14523.
(5) Denk, M.; Rodezno, J . M.; Gupta, S.; Lough, A. J . J . Organomet.
Chem. 2001, 617-618, 242.
(6) Danopoulos, A. A.; Winston, S.; Gelbrich, T.; Hursthouse, M. B.;
Tooze, R. P. Chem. Commun. 2002, 482.
(7) Alder, R. W.; Allen, P. R.; Murray, M.; Orpen, A. G. Angew.
Chem., Int. Ed. Engl. 1996, 35, 1121.
(8) (a) Herrmann, W. A.; Elison, M.; Fischer, J .; Ko¨cher, C.; Artus,
G. R. J . Chem. Eur. J . 1996, 2, 722. (b) Herrmann, W. A.; Ko¨cher, C.;
Goossen, L. J .; Artus, G. R. J . Chem. Eur. J . 1996, 2, 1627.
(9) Kuhn, N.; Kratz, T. Synthesis 1993, 561.
(10) For reviews, see: (a) Kirmse, W. Carbene Chemistry; Academic
Press: New York, 1964. (b) Nefedov, O. M.; Ioffe, A. I.; Menchikov, L.
G. Chemistry of Carbenes; Chemistry: Moscow, 1990. (c) Shvaika, O.
P.; Korotkikh, N. I.; Aslanov, A. F. Chem. Heterocycl. Compd. (Latvia)
1992, 9, 1155. (d) Regitz, M. Angew. Chem., Int. Ed. Engl. 1996, 35,
725. (e) Herrmann, W. A.; Ko¨cher, C. Angew. Chem., Int. Ed. Engl.
1997, 36, 2162. (f) Arduengo, A. J ., III. Acc. Chem. Res. 1999, 32, 913.
(g) Bourissou, D.; Guerret, O.; Gabba¨ı. F. P.; Bertrand, G. Chem. Rev.
2000, 100, 39. (h) Carmalt, C. J .; Cowley, A. H. Adv. Inorg.Chem. 2000,
50, 1.
(11) (a) Enders, D.; Breuer, K.; Raabe, G.; Runsink, J .; Teles, J . H.;
Melder, J . P.; Ebel, K.; Brode, S. Angew. Chem., Int. Ed. Engl. 1995,
34, 1021. (b) Enders, D.; Breuer, K.; Runsink, J .; Teles, J . H. Liebigs
Ann. Chem. 1996, 2019.
10.1021/jo034234n CCC: $25.00 © 2003 American Chemical Society
Published on Web 06/13/2003
5762
J . Org. Chem. 2003, 68, 5762-5765

SCHEME 1
reaction being monitored by the volume of hydrogen
evolved. Compounds 2a and 2c were prepared in isolated
yields of 64 and 51%, respectively, by method A, while
the isolated yields of 2a , 2b, and 2d using method B were
40, 95, and 73%, respectively. Generally speaking, the
yields realized by both methods A and B12 are comparable
to that reported by Enders et al.11 for the preparation of
a triphenyl-substituted 1,2,4-triazol-5-ylidene (63%). How-
ever, methods A and B have the twin advantages of being
one-step procedures that also involve milder reaction
conditions. Moreover, in contrast to the methods em-
ployed for the synthesis of imidazol-2-ylidenes, methods
A and B avoid the evaporation of solvent and the
extraction of the product with aromatic solvents.
differ only slightly. The remaining three intra-ring bond
distances increase when the triazolium cation undergoes
deprotonation. In particular, the average C-N bond
distance at the carbenic carbon is ∼0.04 Å less in the
triazolium cation than that in the resulting carbene.
Such a change is expected from the standpoint of the
development of a positive charge at C(5), the increased
s-character as the angle at this center increases from
100.3(3)° to 107.6(3)°, and possibly on account of in-
creased conjugation between nitrogen lone pairs and the
vacant C(2p) orbital. The observed N-C-N bond angle
of ∼100° is typical of that found for other singlet
carbenes.10
The reactivities of representative 1,2,4-triazoline-5-
ylidenes with acetonitrile, elemental sulfur and elemental
selenium have also been investigated. Interestingly, the
present work represents the first report of the reaction
of a heteroaromatic carbene 1,2,4-triazoline-5-ylidene
with CH3CN. Previously, Enders et al.11 reported that
attempts to isolate insertion products of their phenyl-
substituted 1,2,4-triazol-5-ylidene into a C-H bond were
unsuccessful and expressed the view that possibly such
reactions would require temperatures that exceeded the
stability of the carbene (>150 °C). On the other hand,
Wanzlick et al.15 reported C-H insertion reactions of 1,3-
diphenyldihydroimidazol-2-ylidene with. e.g., cyclopen-
tanone and nitromethane. However, the products were
not identified definitively, and moreover, it is not clear
whether the observed reactivities emanated from the
monomer or the corresponding dimer. More recently,
Arduengo et al.16 have reported that 1,3-dimesityldihy-
droimidazol-2-ylidene will undergo C-H insertion reac-
tions with inter alia CH3CN. However, the analogous
unsaturated (heteroaromatic) carbene 1,3-diadamantyl-
imidazol-2-ylidene failed to react with CH3CN but in-
stead yielded a CH3CN solvate. Herrmann et al.7e have
also noted the failure of imidazol-2-ylidenes to react with
CH3CN. In a preliminary report, we addressed the
possibility that stable heteroaromatic carbenes would
undergo reaction with acetonitrile.17 In the present work,
we have found that a benzene solution of 1,2,4-triazol-
5-ylidene 2a reacts with CH3CN in a sealed tube at 100
°C to afford 1-(1-adamantyl)-3,4-diphenyl-5-cyanomethyl-
5H-1,2,4-triazoline, 3 (Scheme 1). According to the 1H
NMR data, the yield of compound 3 in the reaction
New compounds 1a -e and 2a -d are white, crystalline
solids that were characterized on the basis of elemental
1
analysis, H NMR, 13C NMR, and infrared spectroscopy
1
(see the Experimental Section). The H NMR spectra of
1a -d are consistent with the presence of the aryl and
adamantyl substituents and the C(5)-H proton peak,
which is present in 1a -d but is absent in 2a -d . In
general, the proton signals for 2a -d are upfield in
comparison with those for 1a -d . In accord with the
proposed structures for 2a -d , the 13C NMR spectra
exhibit carbene carbon (C 5) resonances in the range δ
210.1 to 212.7 and triazole carbon (C 3) resonances in
the range δ 149.8-152.6.
Compounds 1e and 2d were also characterized by
X-ray crystallography.13 ORTEP drawings and metrical
parameters are available as Supporting Information. The
triazolium rings of 1e and 2d are both planar as reflected
by the sums of ring bond angles of 539.1(3)° and 539.9-
(3)°, respectively. In each case, the two aryl substitu-
ents are twisted out of the plane of the N3C2 ring. The
C(3)-N(2) bond distances in 1e (1.315(4) Å) and 2d
(1.300(5) Å) correspond essentially to a bond order of two.
The C(3)-N(4) bond distances are virtually identical in
the two structures, and the C(3)-N(2) bond distances
(12) We note, however, that it is not possible to prepare 2c by
method B.
(13) Crystal Data. 1e: C24H24Br3N3, M ) 594.19, monoclinic, space
group C2/c, a ) 28.819(5) Å, b ) 10.496(5) Å, c ) 19.591(5) Å, â )
119.054(5)°, V ) 5180(3) Å3, Dcalcd ) 1.905 g cm-3, Z ) 4, λ (Mo KR) )
0.71073 Å, µ (Mo KR) ) 5.859 mm-1. 2d : C24H23Br2N3, M ) 513.27,
triclinic, space group P-1, a ) 7.489(5) Å, b ) 12.008(5) Å, c ) 12.485-
(5) Å, R ) 80.890(5)°, â ) 75.043(5)°, γ ) 79.011(5)°, Dcalcd ) 1.612 g
cm-3, Z ) 2, λ (Mo KR) ) 0.71073 Å, µ (Mo-KR) ) 3.848 mm-1. Totals
of 6955 and 5309 independent reflections were collected for 1e and
2d , respectively at 153(2) K on a Nonius Kappa diffractometer. Both
structures were solved by direct methods and refined by full-matrix,
least-squares on F2 using the Siemens SHELX PLUS 5.0 (PC) software
package14 to R1 ) 0.0509, wR2 ) 0.1089 for 1e and R1 ) 0.0499, wR2
) 0.1107 for 2d .
(14) Sheldrick, G. M. SHELX PC version 5.0. Siemens Analytical
X-ray Instruments, Inc. 1994.
(15) (a) Wanzlick H.-W.; Schickora, E. Chem. Ber. 1961, 94, 2389.
(b) Wanzlick, H.-W.; Kleiner H.-J . Chem. Ber. 1963, 96, 3094. (c)
Wanzlick, H.-W.; Ahrens, H. Chem. Ber. 1964, 97, 2447. (d) Wanzlick,
H. W.; Ahrens, H. Chem. Ber. 1966, 99, 1580.
(16) Arduengo, A. J ., III; Calabrese, J . C.; Davidson, F.; Dias, H. V.
R.; Goerlich, J . R.; Krafczyk, R.; Marshall, W. J .; Tamm, M.; Schmut-
zler, R. Helv. Chim. Acta 1999, 82, 2348.
(17) Korotkikh, N. I.; Rayenko, G. F.; Shvaika, O. P. Rep. Ukr. Acad.
Sci. 2000, 2, 135.
J . Org. Chem, Vol. 68, No. 14, 2003 5763

10.59 (s, 1H, CHN). Anal. Calcd for C24H25BrClN3O4: C, 53.9;
H, 4.7; Br, 14.9; Cl, 6.6; N, 7.9. Found: C, 53.7; H, 4.8; Br, 14.8;
Cl, 6.7; N, 8.1.
1-(1-Ad a m a n tyl)-3-p h en yl-4-(R-n a p h th yl)-1,2,4-tr ia zoli-
u m p er ch lor a te (1c): yield 79%; mp 256-257 °C (acetic acid);
1H NMR (DMSO-d6, 200 MHz) 1.90 (m, 6H), 2.19 (m, 3H), 2.22
(m, 6H, 1-Ad), 7.40 (m, 5H), 7.87 (m, 4H), 8.05 (d, 1H), 8.08 (d,
1H), 8.17 (d, 1H, J ) 8.2 Hz, Ar), 10.39 (s, 1H, CHN). Anal. Calcd
for C28H28ClN3O4: C, 66.5; H, 5.6; Cl 7.0; N, 8.3. Found: C, 66.6;
H, 5.7; Cl, 7.1; N, 8.1.
mixture is approximately 50%; however, the isolated yield
is 30%. Compound 3 can also be prepared directly from
the triazolium salt 1a by heating the crude reaction
mixture resulting from the preparation of 2a at 60 °C
for 1 h. The overall yield of 3 in this case was 18%. White
solid 3 was characterized by elemental analysis, 1H NMR,
13C NMR, and IR spectroscopy (see the Experimental
Section). Noteworthy are the C-H and CH2CN reso-
nances at δ 5.22 and 2.70 with a J HH of 5.1 Hz in the H
NMR spectrum and signals corresponding to NCN (δ
78.5), CtN (δ 117.9), and CH2 carbon atoms (δ 30.1) in
the 13C NMR spectrum. As postulated by Moss et al.,18
carbenes can undergo X-H insertion reactions by elec-
trophilic or nucleophilic pathways (or possibly via a route
intermediate between these extremes). Since 1,2,4-tri-
azol-5-ylidene 2a is strongly nucleophilic, it is expected
to undergo reaction with CH3CN via the nucleophilic or
concerted pathway shown in Scheme 1.
As a further indication of the strongly nucleophilic
character of the 1,2,4-triazol-5-ylidene carbenes, 2a was
treated with elemental sulfur in benzene and 2d was
allowed to react with elemental selenium in toluene
solution. The resulting thione (4) and selenone (5) were
formed in high yields (84-94%) within minutes at room
temperature. Similar reactions have been reported by
Enders et al.11b for a triphenyl-substituted 1,2,4-triazol-
5-ylidene and are well-known for imidazol-2-ylidenes.10
3
1
1-(1-Ad a m a n t yl)-3,4-d i(p -b r om op h en yl)-1,2,4-t r ia zoli-
u m p er ch lor a te (1d ): yield 79%; mp 270-273 °C (dimethyl-
1
formamide); H NMR (DMSO-d6, 200 MHz) 1.78 (m, 6H), 2.29
(m, 9H, 1-Ad), 7.39 (m, 2H), 7.60 (d, 2H), 7.75 (d, 2H), 7.86 (d,
2H, J ) 8.0 Hz, Ar), 10.60 (s, 1H, CHN). Anal. Calcd for C24H24
-
Br2ClN3O4: C, 47.0; H, 3.9; Br, 26.0; Cl, 5.8; N, 6.9. Found: C,
47.1; H, 3.9; Br, 26.1; Cl, 5.9; N, 6.7.
1-(1-Ad a m a n t yl)-3,4-d i(p -b r om op h en yl)-1,2,4-t r ia zoli-
u m br om id e (1e): yield 81%; mp 242-243 °C (water). The 1H
NMR spectrum of 1e is identical to that of 1d . Anal. Calcd for
C24H24Br3N3: C, 48.5; H, 4.1; Br, 40.3; N, 7.1. Found: C, 48.6;
H, 4.2; Br, 40.2; N, 7.1.
1-(1-Adam an tyl)-3,4-diar yl-1,2,4-tr iazol-5-yliden es. Meth -
od A. Potassium tert-butoxide (0.56 g, 5 mmol) was added all
at once to a suspension of the triazolium perchlorate (5 mmol)
in benzene (15 mL) under an argon atmosphere. After the
reaction mixture had been stirred for 0.5 h, the precipitate of
KClO4 was removed by filtration and the solvent was evaporated
from the filtrate under reduced pressure. The resinous residue
was triturated with 2-3 mL of hexane to afford the triazol-5-
ylidenes that were recrystallized from toluene.
1-(1-Ad a m a n tyl-3,4-d ia r yl-1,2,4-tr ia zol-5-ylid en es. Meth -
od B. A 55% dispersion of sodium hydride (0.05 g, 1.1 mmol in
mineral oil) was added all at once to a solution of the triazolium
perchlorate (1 mmol) in 2-5 mL of CH3CN. The progress of the
reaction was monitored by the volume of hydrogen evolved. At
the end of the reaction, the resulting 1,2,4-triazol-5-ylidene was
filtered off, washed with CH3CN and hexane, and recrystallized
from toluene or toluene/hexane mixtures.
1-(1-Ad a m a n t yl)-3,4-d ip h e n yl-1,2,4-t r ia zol-5-ylid e n e
(2a ): yields of 64% and 40% by methods A and B, respectively;
mp 167-169 °C (hexane); 1H NMR (C6D6, 200 MHz) 1.66 (m,
6H), 2.11 (m, 3H), 2.64 (m, 6H, 1-Ad), 6.95-7.38 (m, 10H, Ar);
13C NMR (C6D6, 50.3 MHz) 30.0, 36.6, 43.9, 59.5 (1-Ad), 126.6,
127.3, 127.8, 128.3, 128.9, 129.3, 140.4 (Ar), 150.9 (C 3), 210.7
(C 5); IR (Nujol mull) 3020 w (C-H Ar), 1590 m, 1540 m (CdC
Ar). Anal. Calcd for C24H25N3: C, 81.1; H, 7.1; N, 11.8. Found:
C, 81.2; H, 7.4; N, 12.0.
1-(1-Ad a m a n tyl)-3-p h en yl-4-(p-br om op h en yl)-1,2,4-tr ia -
zol-5-ylid en e (2b): yield of 95% by method B; mp 174-175 °C
dec (10:1 hexane/toluene); 1H NMR (C6D6, 200 MHz) 1.65 (m,
6H), 2.11 (m, 3H), 2.66 (m, 6H, 1-Ad), 6.93 (m, 5H), 7.33 (m,
4H, Ar); 13C NMR (C6D6, 50.3 MHz) 30.5, 36.9, 44.4, 60.0 (1-
Ad), 127.8, 128.3, 128.4, 128.8, 129.5, 129.9, 132.4, 139.6 (Ar),
150.3 (C 3), 210.6 (C 5); IR (Nujol mull) 3020 w (C-H Ar), 1580
m, 1510 m (CdC Ar). Anal. Calcd for C24H24BrN3: C, 66.4; H,
5.6; Br, 18.4; N, 9.7. Found: C, 66.8; H, 5.5; Br, 18.5; N, 9.8.
1-(1-Ad a m a n tyl)-3-p h en yl-4-(r-n a p h th yl)-1,2,4,-tr ia zol-5-
ylid en e (2c): yield of 51% by method A; mp 82-83 °C (10:1
hexane/toluene); 1H NMR (C6D6, 200 MHz) 1.69 (m, 6H), 2.14
(m, 3H), 2.72 (m, 6H, 1-Ad), 6.77 (m, 2H), 6.99 (m, 1H), 7.15 (m,
5H), 7.47 (m, 3H), 7.90 (m, 1H, Ar); 13C NMR (C6D6, 50.3 MHz)
30.0, 36.5, 43.8, 60.3 (1-Ad), 123.6, 125.5 126.3, 126.8, 127.1,
127.4, 128.0, 129.3, 129.7, 130.6, 134.6, 136.0 (Ar), 152.6 (C 3),
212.7 (C 5); IR (Nujol mull) 3060 w (C-H Ar), 1600 m, 1540 m,
1530 m (CdC Ar). Anal. Calcd for C28H27N3: C, 82.9; H, 6.7; N,
10.4. Found: C, 82.8; H, 6.9; N, 10.5.
Exp er im en ta l Section
Gen er a l Met h od s. All experiments with the triazol-5-
ylidenes were carried out under an argon atmosphere. All sol-
vents were dried by standard methods prior to use. H and 13C
1
NMR chemical shifts are reported relative to tetramethylsilane
(TMS, δ ) 0.00) as internal standard. IR spectra were measured
as Nujol mulls and thin-layer chromatography was performed
on silica gel with chloroform or a 10:1 mixture of chloroform and
methanol as eluent, followed by development with iodine.
Elemental analyses were carried out at the Litvinenko Institute
of Physical Organic and Coal Chemistry.
CAUTION. Although we have not experienced any problems
with the perchlorate salts described herein, the usual precau-
tions should be taken when handling these compounds.
1-(1-Ad a m a n tyl)-3,4-d ia r yl-1,2,4-tr ia zoliu m P er ch lor a tes
(1a -d ). Gen er a l P r oced u r e. A mixture of the 3,4-diaryl-1,2,4-
triazole (10 mmol) and 1-bromoadamantane (2.15 g, 10 mmol)
in acetic acid (3 mL) was refluxed for 8-10 h, following which
an additional portion of 1-bromoadamantane (0.47 g, 2 mmol)
was added and heating was continued for 4-5 h. Subsequent
filtration of the precipitate, followed by extraction of salt with
hot water (90-95 °C), afforded the pure bromide salts. Each
bromide salt was converted into the corresponding perchlorate
salt by the treatment with excess sodium perchlorate (1.84 g,
15 mmol) in aqueous solution.
1-(1-Ad a m a n tyl)-3,4-d ip h en yl-1,2,4-tr ia zoliu m p er ch lo-
r a te (1a ): yield 96%, mp 223-224 °C (acetic acid); 1H NMR
(DMSO-d6, 200 MHz) 1.78 (m, 6H), 2.31 (m, 9H, 1-Ad), 7.46 (m,
5H), 7.64 (m, 5H, Ar), 10.58 (s, 1H, CHN). Anal. Calcd for C24H26
ClN3O4: C, 63.2; H, 5.7; Cl, 7.8; N, 9.2. Found: C, 63.1; H, 5.7;
Cl, 7.9; N, 9.2.
1-(1-Ad a m a n tyl)-3-p h en yl-4-(p-br om op h en yl)-1,2,4-tr ia -
zoliu m p er ch lor a te (1b): yield 71%; mp 266-268 °C (acetic
acid); 1H NMR (DMSO-d6, 200 MHz) 1.78 (m, 6H), 2.31 (m, 9H,
1-Ad), 7.49 (m, 5H), 7.59 (d, 2H), 7.87 (d, 2H, J ) 8.0 Hz, Ar),
-
1-(1-Ad a m a n t yl)-3,4-d i(p -b r om op h en yl)-1,2,4-t r ia zol-5-
ylid en e (2d ): yield of 73% by method B; mp 155 °C dec (10:1
hexane/toluene); 1H NMR (C6D6, 200 MHz) 1.65 (m, 6H), 2.11
(m, 3H), 2.66 (m, 6H, 1-Ad), 6.85 (m, 1H), 6.90 (m, 1H), 6.99 (m,
1H), 7.00 (m, 4H), 7.04 (m, 1H, Ar); 13C NMR (C6D6, 50.3 MHz)
30.1, 36.6, 44.0, 59.8 (1-Ad), 121.5, 124.3, 126.5, 129.3, 130.7,
131.7, 131.8, 138.9 (Ar), 149.8 (C 3); 210.1 (C 5); IR (Nujol mull)
(18) (a) Moss, R. A.; Shen, S.; Wlostowski, M. Tetrahedron Lett. 1988,
29, 6417. (b) Du, X. M.; Fan, H.; Goodman, J . L.; Kesselmayer, M. A.;
Krogh-J espersen, K.; LaVilla, J . A.; Moss, R. A.; Shen, S.; Sheridan,
R. S. J . Am. Chem. Soc. 1990, 112, 1920. See also (c) Pezacki, J . P.
Can. J . Chem. 1999, 77, 1230.
5764 J . Org. Chem., Vol. 68, No. 14, 2003

3020 w (C-H Ar), 1590 m (CdC Ar). Anal. Calcd for C24H23
-
39.3, 63.6 (1-Ad), 127.1, 127.6, 128.1, 128.4, 128.7, 129.1, 129.4,
130.0 (Ar), 141.1 (C 3), 166.5 (C 5); IR (Nujol mull) 3055 w, 3030
w (C-H Ar), 1685 m (N-CdS), 1595 m, 1500 sh (CdC Ar). Anal.
Calcd for C24H25N3S: C, 74.4; H, 6.5; N, 10.8; S, 8.3. Found: C,
74.7; H, 6.7; N, 10.8; S, 8.1.
Br2N3: C, 56.2; H, 4.5; Br, 31.1; N, 8.2. Found: C 56.4; H 4.7;
Br 31.3; N 8.2.
1-(1-Ad a m a n t yl)-3,4-d ip h en yl-5-cya n om et h yl-5H -1,2,4-
tr ia zolin e (3). Acetonitrile (2 mL) was added to a solution of
1,2,4-triazol-5-ylidene 2a (0,7 g, 1,97 mmol) in 1 mL of benzene.
The reaction mixture was sealed in a glass ampule and heated
at 100 °C for 10 h. The solvent was removed under reduced
pressure, and the resulting resinous material was dissolved in
5 mL of benzene then filtered through a thin layer of silica gel
(40/100 mµ). The resinous residue obtained by removing the
solvent in vacuo was triturated with 5 mL of hexane to afford a
30% yield of 3 (0.23 g).
1-(1-Ad a m a n t yl)-3,4-d i(p -b r om op h en yl)-1,2,4-t r ia zol-5-
selen on e (5). Amorphous selenium (0.04 g, 0.05 mmol) was
added to a stirred solution of carbene 2d (0.055 g, 0.1 mmol) in
toluene (2 mL) at room temperature. After being stirred over-
night, the reaction mixture was filtered, and the filtrate was
evaporated to produce 0.05 g of a microcrystalline powder that
was recrystallized from a mixture of toluene-hexane (1:1) to
afford 5: 84% yield; mp 238-240 °C (2-propanol); 1H NMR
(CDCl3, 200 MHz) 1.79 (m, 6H) 2.28 (m, 3H), 2.79 (m, 6H, 1-Ad),
7.15-7.21 (m, 4H), 7.46 (m, 2H), 7.64 (m, 2H, Ar); 13C NMR
(CDCl3, 200 MHz) 30.0, 36.0, 39.8, 65.3 (1-Ad), 124.3, 125.3,
128.6, 129.7, 130.6, 132.1, 133.0, 134.4 (Ar), 148.8 (C 3), 160.0
(C 5); IR (Nujol mull) 3040 w (C-H Ar), 1705 m (N-CdSe), 1600
w, 1485 sh (CdC Ar). Anal. Calcd for C24H23Br2N3Se: C, 48.7;
H, 3.9; Br, 27.0; N, 7.1; Se, 13.3. Found: C, 48.6; H, 3.9; Br,
26.8; N, 7.1; Se, 13.5.
Compound 3 can also be prepared by treating 1a (0.5 g, 1.1
mmol) with a 55% dispersion of sodium hydride (0.5 g, 1.2 mmol)
in 2 mL of CH3CN at 20 °C, followed by heating the reaction
mixture to 60 °C for 1 h. After being allowed to stand overnight,
the reaction mixture was filtered through a thin layer of neutral
silica gel and worked up as described above: yield 18% (0.08 g);
1
mp 133-134 °C (acetonitrile); H NMR (CDCl3, 200 MHz) 1.63
(m, 6H), 1.81 (m, 3H), 2.09 (m, 6H, 1-Ad), 2.70 (dd, J ) 5.1 Hz,
CH2CN), 5.22 (t, 1H, J ) 5.1 Hz, CHN), 7.10 (m, 4H), 7.25 (m,
4H), 7.62 (m, 2H, Ar); 13C NMR (CD3CN, 200 MHz) 30.1 (CH2C),
30.4, 37.2, 40.4, 57.8 (1-Ad), 117.9 (CtN); 125.7, 126.5, 128.7,
129.4, 129.9, 130.2, 130.3, 144.9 (Ar), 151.0 (C 3); IR (Nujol mull)
3025 w (C-H Ar), 2235 m (C≡N), 1585 m, 1560 m, 1485 (CdC
Ar). Anal. Calcd for C26H28N4: C, 78.8; H, 7.1; N, 14.1. Found:
C, 78.9; H, 7.0; N, 14.4.
Ack n ow led gm en t. We thank the Ukrainian State
Foundation of the Fundamental Research and the
Education and Science Ministry of Ukraine for financial
support (Grant No. 03.07/00). We also thank the Robert
A. Welch Foundation for financial support of the X-ray
diffraction studies. We also express gratitude to Dr. K.
J u Chotiy (Donetsk) for the IR spectroscopic data.
1-(1-Ad a m a n tyl)-3,4-d ip h en yl-1,2,4-tr ia zol-5-th ion e (4).
A solution of carbene 2a (0.39 g, 1.1 mmol) in benzene (1 mL)
was added dropwise to a stirred solution of elemental sulfur
(0.049 g, 1.56 mmol) in benzene (5 mL). The resulting reaction
mixture was evaporated to dryness in vacuo to afford thione 4
in 94% yield: mp 205-207 °C (2-propanol); 1H NMR (CDCl3,
200 MHz) 1.78 (m, 6H), 2.27 (m, 3H), 2.75 (m, 6H, 1-Ad), 7.35
(m, 5H), 7.50 (m, 5H, Ar); 13C NMR (CDCl3, 200 MHz) 29.8, 36.0,
Su p p or tin g In for m a tion Ava ila ble: ORTEP drawings
and tables of crystallographic data for 1e and 2d . This material
is available free of charge via the Internet at http://pubs.acs.org.
J O034234N
J . Org. Chem, Vol. 68, No. 14, 2003 5765