Tautomerism in the solid state and in solution of a series of 6-aminofulvene-1-aldimines

Article abstract of DOI:10.1021/jo010625v

To study systems able to sustain intramolecular proton-transfer, we have prepared a series of six aminofulvene aldimines including several labeled with ¹⁵N and ²H. These compounds show coupling constants through the hydrogen bond, ^1hJ(¹⁵N-¹H) and ^2hJ(¹⁵N-¹⁵N). The position of the tautomeric equilibria, i.e., on what nitrogen atom is the proton, was determined in the solid state and in solution. The crystal structure of N{([5-[(phenylamino)methylene]- 1,3-cyclopentadien-1-yl]methylene})pyrrole-1-amine (3) has been determined by X-ray analysis. In solution, both N-H and C-H tautomers were observed and their structures assigned by NMR spectroscopy. Particularly useful is the value of the ¹J(¹⁵N-¹H) coupling constant.

Full text of DOI:10.1021/jo010625v

1462
J . Org. Chem. 2002, 67, 1462-1471
Ta u tom er ism in th e Solid Sta te a n d in Solu tion of a Ser ies of
6-Am in ofu lven e-1-a ld im in es
Dionisia Sanz,*,† Marta Pe´rez-Torralba,† Sergio Hugo Alarco´n,†,| Rosa Mar´ıa Claramunt,*,†
Concepcio´n Foces-Foces,*,‡ and J ose´ Elguero§
Departamento de Quı´mica Orga´nica y Biologı´a, Facultad de Ciencias, UNED,
Senda del Rey 9, E-28040, Madrid, Spain; Departamento de Cristalografı´a, Instituto de Quı´mica Fı´sica
‘Rocasolano’, CSIC, Serrano 119, E-28006, Madrid, Spain; and Instituto de Qu´ımica Me´dica, Centro de
Quı´mica Orga´nica ‘Manuel Lora-Tamayo’, CSIC, J uan de la Cierva 3, E-28006, Madrid, Spain
rclaramunt@ccia.uned.es
Received J une 18, 2001
To study systems able to sustain intramolecular proton-transfer, we have prepared a series of six
2
aminofulvene aldimines including several labeled with 15N and H. These compounds show coupling
constants through the hydrogen bond, 1hJ (15N-1H) and 2hJ (15N-15N). The position of the tautomeric
equilibria, i.e., on what nitrogen atom is the proton, was determined in the solid state and in solution.
The crystal structure of N{[5-[(phenylamino)methylene]-1,3-cyclopentadien-1-yl]methylene}pyrrole-
1-amine (3) has been determined by X-ray analysis. In solution, both N-H and C-H tautomers
were observed and their structures assigned by NMR spectroscopy. Particularly useful is the value
1
of the J (15N-1H) coupling constant.
In tr od u ction
It appears that aminofulvene-aldimines are the only
representatives of a pseudo seven-membered ring, i.e., a
case where the proton leaves a nitrogen atom that is five
bonds separated from the nitrogen that receives it.
There is an increasing interest in the structure of
systems presenting inter- or intramolecular hydrogen
bonds (IMHB). Within these systems, our major interest
lies on the phenomenon of proton transfer in the solid
state: solid-state proton transfer (SSPT) either inter- or
intramolecular. An attempt to classify these systems
takes into account the number of bonds that separates
the HB donor from the HB acceptor. In addition, the
number of protons involved in the transfer process allows
a finer classification. To avoid a picture too complex, we
will limit ourselves to oxygen and nitrogen atoms in-
volved in the X-H‚‚‚Y HB. We have summarized in Table
1 (refs 1-15) the information presently available about
these systems where SSPT has been observed or has been
postulated.
Resu lts a n d Discu ssion
Ch em istr y. Although aminofulvene-1-aldimines were
studied by Mu¨ller-Westerhoff in the seventies,16 only one
aromatic compound was prepared, the bis phenyl deriva-
tive (1), the same that was studied by X-ray crystal-
lography,17 and, subsequently, by J ackman who mea-
sured the deuteron spin-lattice relaxation times and
calculated the deuteron quadrupole coupling constants.18
We have synthesized
1 and six other aromatic
* To whom correspondence should be addressed. R. Claramunt:
rclaramunt@ccia.uned.es. D. Sanz: dsanz@ccia.uned.es.
† Facultad de Ciencias, UNED.
(8) (a) Gan, Z.; Ernst, R. R. J . Chem. Phys. 1998, 108, 9444. (b)
Sugawara, T.; Takasu, I. Adv. Phys. Org. Chem. 1999, 32, 219.
(9) Scherer, G.; Limbach, H.-H. J . Am. Chem. Soc. 1994, 116, 1230.
(10) (a) Wolf, K.; Mikenda, W.; Nusterer, E.; Schwarz, K.; Ulbricht,
C. Chem. Eur. J . 1998, 4, 1418. (b) Poupko, R.; Luz, Z.; Destro, R. J .
Phys. Chem. A 1997, 101, 5097. (c) Loerting, T.; Liedl, K. R. J . Am.
Chem. Soc. 1998, 120, 12595.
(11) (a) Svensson, C.; Abrahams, S. C. Acta Crystallogr. Sect. B 1986,
42, 280. (b) Tegenfeldt, J .; Ojamae, L.; Svensson, C. J . Chem. Phys.
1991, 95, 2696.
‡ Instituto Rocasolano, CSIC.
§ Instituto de Qu´ımica Me´dica, CSIC.
| On leave from the Departamento de Qu´ımica Anal´ıtica, Facultad
de Ciencias Bioqu´ımicas y Farmace´uticas, Universidad Nacional de
Rosario, Suipacha 531, Rosario (2000), Argentina.
(1) Ugalde, J . M.; Alkorta, I.; Elguero, J . Angew. Chem., Int. Ed.
2000, 39, 717.
(2) Aguilar-Parrilla, F.; Scherer, G.; Limbach, H.-H.; Foces-Foces,
C.; Cano, F. H.; Elguero, J . J . Am. Chem. Soc. 1992, 114, 9657.
(3) Foces-Foces, C.; Alkorta, I.; Elguero, J . Acta Crystallogr. Sect. B
2000, 56, 1018.
(4) Smith, J . A. S.; Wehrle, B.; Aguilar-Parrilla, F.; Limbach, H.-
H.; Foces-Foces, C.; Cano, F. H.; Elguero, J .; Baldy, A.; Pierrot, M.;
Khurshid, M. M. T.; Larcombe, J . B. J . Am. Chem. Soc. 1989, 111,
7304.
(5) Llamas-Saiz, A. L.; Foces-Foces, C.; Fontenas, C.; J agerovic, N.;
Elguero, J . J . Mol. Struct. 1999, 484, 197.
(6) Neumann, M. A.; Cracium, S.; Corval, A.; J ohnson, M. R.;
Horsewill, A. J .; Berderskii, V. A.; Trommsdorff, H. P. Ber. Bunsen-
Ges. Phys. Chem. 1998, 102, 325.
(12) (a) Wehrle, B.; Aguilar-Parrilla, F.; Limbach, H.-H. J . Magn.
Reson. 1990, 87, 584. (b) McGregor, A. C.; Lukes, P. J .; Osman, J . R.;
Crayston, J . A. J . Chem. Soc., Perkin Trans. 2 1995, 809.
(13) (a) Braun, J .; Koecher, M.; Schlabach, M.; Wehrle, B.; Limbach,
H.-H.; Vogel, E. J . Am. Chem. Soc. 1994, 116, 3261. (b) Claramunt, R.
M.; Elguero, J .; Katritzky, A. R. Adv. Heterocycl. Chem. 2000, 77, 1.
(14) Claramunt, R. M.; Sanz, D.; Alarco´n, S. H.; Pe´rez Torralba, M.;
Elguero, J .; Foces-Foces, C.; Pietrzak, M.; Langer, U.; Limbach, H.-H.
Angew. Chem., Int. Ed. 2001, 40, 420.
(15) Pietrzak, M.; Limbach, H.-H.; Pe´rez Torralba, M.; Sanz, D.;
Claramunt, R. M.; Elguero, J . Magn. Reson. Chem. 2001, 39, S100.
(16) Mu¨ller-Westerhoff, U. J . Am. Chem. Soc. 1970, 92, 4849.
(17) Ammon, H. L.; Mu¨ller-Westerhoff, U. Tetrahedron 1974, 30,
1437.
(7) (a) Limbach, H. H.; Meschede, L.; Scherer, G. Z. Naturforsch.
1989, 44a, 459. (b) Ma¨nnle, F.; Waver, I.; Limbach, H.-H. Chem. Phys.
Lett. 1996, 256, 657.
(18) J ackman, L. M.; Trewella, J . C.; Haddon, R. C. J . Am. Chem.
Soc. 1980, 102, 2519.
10.1021/jo010625v CCC: $22.00 © 2002 American Chemical Society
Published on Web 02/05/2002

Tautomerism of 6-Aminofulvene-1-aldimines
Ta ble 1. System s th a t P r esen t In ter - or In tr a m olecu la r HBs (IMHB) a n d SSP Ta
size
J . Org. Chem., Vol. 67, No. 5, 2002 1463
no. of H
1H
0
1
2
3
4
5
Malonaldehyde and other
â-dicarbonyl compounds [10]
9-Hydroxyphenalenone [11]
DTTA [12]
Fu lven es [14, 15]
2H
(H2O)2 [1]
(pyrazole)2 [2,3]
(RCO2H) [6]
Tropolone [8]
(Amidine)2 [7]
Oxalamidines [9]
Porphyrine [13]
3H
4H
(H2O)3 [1]
(H2O)4 [1]
(pyrazole)3 [3,4]
(pyrazole)4 [3,5]
a
In italic: intramolecular processes. References in brackets.
Sch em e 1. Syn th esis of Am in ofu lven ea ld im in es
(heteroaromatic) derivatives 2-7 as well as several of
most relevant information is reported in Scheme 1. When
R1 is Ph, A is not isolated and B, R1 ) R2 ) Ph (1), is
directly formed [its N-methylation affords C (12)]. In the
case of 4-amino-1,2,4-triazole, A (13) was isolated and
then reacted with PhNH2 to afford B (2) which can then
be methylated to obtain C (14). Compounds 5 and 6 are
analogues of 2 which were prepared in a similar fashion.
Note that the methylation takes place on the aniline
nitrogen, N1, and not on the triazole nitrogen N9.
Compound (13) was treated with 4-amino-1,2,4-triazole,
but the symmetrical bis-triazolyl derivative was not
obtained.
2
their derivatives labeled with 15N and H.
The reaction of (11) with 1-aminopyrrole affords A (15)
together with B (4). The subsequent reaction of A (15)
with aniline leads to B (3). Finally, the use of 1,3-
dimethyl-5-amino-1,2,4-triazole provides A (16) which
was transformed into B (7) by reaction with aniline. The
reactions were stopped when aniline or toluidine started
to replace the heterocyclic residues. Also, in some cases
we have isolated the corresponding aldehydes resulting
from the hydrolysis of the [CdNMe2}+ groups, as simi-
larly observed by Mu¨ller-Westerhoff.16
Som e NMR Ch a r a cter istics of th e 6-Am in ofu l-
ven e-1-a ld im in es. Table 2 reports several values of
coupling constants through a hydrogen bond, both 1hJ (15N-
1H) and 2hJ (15N-15N). We have devoted some effort to
study these couplings in 1 and 2.14,15
Such couplings are easy to measure in dissymmetric
15N-labeled compounds. For the symmetric ones, 1a and
4a , it is necessary to use indirect techniques.15
Stu d y of Ta u tom er ic Equ ilibr ia . The aminofulvene-
1-aldimines of Scheme 1 present an interesting case of
tautomerism. All of them have five possible tautomers
(Figure 1) although some tautomers are degenerate, such
as 1a and 1b, 1c and 1e, 4a and 4b, and 4c and 4e. The
The synthetic procedures are described in the Experi-
mental Section. Concerning the chemical aspects, the

1464 J . Org. Chem., Vol. 67, No. 5, 2002
Sanz et al.
Ta ble 2. Exp er im en ta l a n d Estim a ted NMR P a r a m eter s of F u lven ea ld im in es (ch em ica l sh ifts in p p m , d ista n ces in
a n gstr om s, cou p lin g con sta n ts in h er tz)a
1h
2h
compd
δ2H (10D)
d(N1-H)
J total
1J N-H
J
J
N‚‚‚N
N‚‚‚H
1a t1b
2a
15.28
12.65
13.15
13.30
13.82
1.008
1.003
1.004
1.002
1.005
81.6
93.0
92.2
95.8
89.1
83.3 (N-Ph)
88.6 (N-Ph)
88.2 (N-Ph)
89.9 (N-Npy)
86.4 (N-Ph)
-1.7 (N-Ph)
4.4 (N-NTr)
4.0 (N-NPy)
5.9 (N-NPy)
2.7 (N-CTr)
10.6
8.7
3a
9.0
4a t4b
7a
- - - -
- - - -
a
In bold are estimated values.
F igu r e 1. Tautomerism of aminofulvenealdimines 1-4.
nonconjugated CH tautomers have been observed only
in the case of 4. In Figure 2 we have represented the case
of 5 and 6 (related to 2), that we have not studied, and
the case of 7 where we have demonstrated that the most
stable tautomer is 7a . The determination of the position
and structure of tautomers has been carried out by X-ray
crystallography for the solid state and by NMR for
solution.
X-r a y St r u ct u r e Det er m in a t ion . The X-ray
structure of 1 was determined by Ammon and Mu¨ller-
Westerhoff,17 but since there is only one possible NH
tautomer for this compound, 1a t1b, the determination
only confirmed its structure. Recently, we have described
the structure of compound 2 (tautomer 2a , the N-H on
the aniline moiety).14 In this paper we have determined
the structure of compound 3 proving that in the solid
state this compound exists as tautomer 3a as shown in
Figure 3.
The molecular structure of 3 presents similar features
to those of compound 2. The N-H amino proton located
on N1, as revealed by the electron density close to this
atom and by the different pattern of bond distances and
angles around N1 and N9 (Table 3), is intramolecular
hydrogen bonded to the imino N9 atom. Clearly, one
F igu r e 2. Tautomerism of aminofulvenealdimines 5-7.
effect of the intramolecular hydrogen bond is the planar-
ity of the molecule as a whole. Although in 2 and 3, the

Tautomerism of 6-Aminofulvene-1-aldimines
J . Org. Chem., Vol. 67, No. 5, 2002 1465
Ta ble 3. Selected Geom etr ica l P a r a m eter s (Å, d eg). G1, G2, a n d G3 Rep r esen ts th e Cen tr oid of th e C3-C7, C10-C15,
a n d N16-C20 Rin gs
N1-C2
1.347(9)
1.246(9)
124.2(6)
9.2(13)
176.8(7)
-2.9(13)
4.1(10)
C2-C3
1.381(10)
1.494(11)
117.5(6)
-2.5(12)
-2.7(10)
-179.2(7)
C8-N9
C7-C8
C2-N1-C10
C2-C3-C7-C8
C7-C8-N9-N16
N1-C2-C3-C7
C2-N1-C10-C11
C8-N9-N16
C3-C7-C8-N9
C8-N9-N16-C20
C3-C2-N1-C10
Hydrogen Bonding Interactions
D-H‚‚‚A
D-H
D‚‚‚A
H‚‚‚A
D-H‚‚‚A
N1-H1‚‚‚N9
1.07
1.04
1.05
1.05
2.829(8)
3.637(8)
3.737(8)
3.851(9)
1.82
2.67
3.00
2.88
154
155
128
154
C20-H20‚‚‚G1(3/2 - x, 1/2 + y, z)
C5-H5‚‚‚G2(1/2 + x, 1/2 - y, -z)
C13-H13‚‚‚G3(-1/2 + x, -1/2 + y, 1/2 - z)
F igu r e 3. Molecular structure of 3. Displacement parameters
are drawn at the 30% level. Dotted lines indicate hydrogen
bonds.
molecules are arranged in a herringbone fashion, Figure
4, the substitution of the 1,2,4-triazole by pyrrole in 3
removes hydrogen bond acceptors in this ring and thereby
prevents the formation of a hydrogen bonded ribbon in 3
as observed in 2. In 3, piles of molecules along the c axis
are linked by C-H‚‚‚π interactions.
NMR Stu d ies Rela ted to Ta u tom er ism . The proton
transfer between nitrogen atoms of tautomers a and b
is fast on the NMR time scale. Therefore only average
signals are expected. On the other hand, the CH/NH
tautomerism is slow and signals of both tautomers are
expected. Only 4 shows evidence of this kind of tautom-
erism. A simple look at the NMR spectra (see Figure 5
and Experimental section) shows that the CH tautomer
lacks symmetry; therefore, 4d must be excluded. By
simple integration of the1H NMR signals the percentages
of 4a (t4b) and 4c (t4e) (Table 4) have been determined.
When D2O is added to a CDCl3 solution of aminofulvene-
1-aldimines, the only signal that disappears is the N(10)H
F igu r e 4. Crystal packing of 3 (a) and 2 (b).
compounds 1a (40.8 Hz) and 4a (47.9 Hz), which, to a
1
first approximation, corresponds to J (15N-1H) ) 81.6
and 95.8 Hz, respectively. Compounds 2 and 3 present a
1J (15N-1H) coupling between N1 and H10 of 88.6 and
88.2 Hz corresponding to 2a and 3a , respectively (See
Figure 6). However, these compounds present also a
1hJ (15N-1H) through the HB coupling of 4.4 and 4.0 Hz,
respectively. Therefore, the values for the symmetrical
compounds correspond to 1J (15N-1H) + 1hJ (15N-1H).
There are linear correlations between J total on one hand
and δ2H and the calculated N1-H distance (Table 2) on
the other: J total ) (157 ( 21) - (4.9 ( 1.6) δ2H, n ) 4, r2
) 0.83, that predicted for 7a ) 89.5 Hz and J total ) (2454
( 181) - (2354 ( 180) d(N1-H), n ) 4, r2 ) 0.988, that
2
with concomitant appearance of a H signal in deuterium
NMR (Table 2). The only exception is compound 4 where,
due to the tautomeric equilibrium between 4a and 4c(t
4e), the CH2 signal at position 4 slowly exchanges first
to CHD and finally to CD2 (2H at 3.65 ppm).
For the a /b tautomerism, the 1J (15N-1H) coupling
constants can be used. These couplings depend on the
substituents on the nitrogen atoms. In the symmetric

1466 J . Org. Chem., Vol. 67, No. 5, 2002
Sanz et al.
F igu r e 5. 1H NMR spectra signals of 4-15N4. in THF-d8 solution, showing the presence of the two tautomers 4a -15N4 and 4c-15N4.
Ta ble 4. Exp er im en ta l a n d Ca lcu la ted (a b in itio HF /6-31G**, k ca l m ol-1) Rela tive Sta bilities of th e Differ en t Ta u tom er s
(betw een p a r en th eses, d ip ole m om en ts in D). Absolu te En er gies of th e Most Sta ble Ta u tom er in Ha r tr ees
compd
experimental
absolute value
tautomer a
tautomer b
tautomer c
tautomer d
tautomer e
1
2
3
4
7
1a t1b
2a
-837.70697 (1a )
-847.75472 (2a )
-815.77410 (3a )
-793.83729 (4a )
-925.89972 (7a )
0 (1.41)
0 (7.95)
0 (2.13)
0 (1.49)
0 (4.55)
0 (1.41)
17.96 (2.52)
-
4.48 (0.80)
8.95 (3.41)
-
15.49 (3.25)
-
12.27 (3.46)
7.31 (4.20)
-
17.96 (2.52)
-
4.68 (0.85)
8.95 (3.41)
-
3.95 (5.58)
2.40 (0.22)
0 (1.49)
3a
65% 4a /35% 4ca
7a
0.70 (2.79)
a
In CDCl3 (in THF-d8, 50% 4a /50% 4c).
(1hJ N‚‚‚H ) 5.9 Hz). All these estimated values are reported
in bold in Table 2.
Finally, compound 7 exists as tautomer 7a as the
coupling constants between N1 and H10 (86.4 Hz) and
between H2 and H10 (13.1 Hz) prove.
Th eor etica l Ca lcu la tion s of Ta u tom er ic Equ ilib-
r ia . We have summarized the experimental findings of
the preceding section in Figure 1 and Table 4. Although
compound 1 clearly exists as tautomer 1a (t1b), we have
calculated the two other tautomers to have an element
of comparison. They are much less stable, between 15
and 18 kcal mol-1 and should not be observed. Com-
pounds 5 and 6 have not been calculated because only
tautomers 5a and 6a were observed and because they
are similar to compound 2 (the substituent at the para
position has no appreciable effect on the tautomerism).
Concerning the “quasi-aromatic” (i.e., conjugated) tau-
tomers, the calculations correctly predict the greater
stability of the Ci-N1-H10 2a and 3a over the N1′-
N9-H10 tautomers 2b and 3b. In the case of the
competition between two C-N-H tautomers, the calcu-
lations favor 7a , in agreement with experimental results,
although the difference with 7b is very small, only 0.7
kcal mol-1. In solution, the more polar tautomer should
be stabilized, which would favored 7a (µ ) 4.55 D) over
7b (µ ) 2.79 D).
F igu r e 6. 1H NMR spectra signals of 3-15N3 in CDCl3 solution,
where only tautomer 3a -15N3 is present.
predicted for 7a ) 88.8 Hz, i.e., 89.1 Hz on average. Since
We have calculated the five different tautomers in the
case of 3. The order of stability is 3a > 3b > 3c > 3e >
3d . The experimental results obtained for 4 (t4b), that
is, 4a and 4c (t4e) being of similar stability and 4d much
less stable, do not correlate well with the calculations,
1
1h
1h
J total ) J N-H
+
J
, to 89.1 Hz corresponds a
J
N‚‚‚H
N‚‚‚H
1
of 2.7 Hz. A third linear relationship, J N-H ) (1192 (
406) - (1100 ( 404) d(N1-H), n ) 3, r2 ) 0.88, predicted
for 1a 83.3 Hz (1hJ N‚‚‚H ) -1.7 Hz) and for 4a 89.9 Hz

Tautomerism of 6-Aminofulvene-1-aldimines
J . Org. Chem., Vol. 67, No. 5, 2002 1467
aminophthalimide (1.33 g, 8.11 mmol), 0.94 g (54%) were
which predict 4a to be more stable than 4c which itself
is more stable that 4d . Note that in the case of 1 where
1c and 1d are not observed, the differences are much
higher. Moreover, there is a statistical effect that favors
symmetric tautomers 1a , 1c, 4a , 4c by a factor of 2.
The calculated geometries are very similar to the
experimental ones for 1a , 2a , and 3a , although the
N‚‚‚N calculated distances are 0.06 Å longer on average.
1
obtained. H NMR (CDCl3) δ 7.99 (m, 2H), 7.85 (m, 2H), 6.74
2
3
4
(m, 2H, J N-H ) 2.5), 6.36 (m, 2H, J N-H ) 7.5, J N-H ) 0.7);
13C NMR (CDCl3) δ 164.3 (1J C-N ) 12.3), 135.0, 129.6 (2J C-N
) 10.8), 124.3, 121.4 (C2′/C5′, J C-N ) 14.4), 109.0 (C3′/C4′,
1
2J C-N ) 6.8); 15N NMR (CDCl3) δ -202.0 (N), -230.1 (NH2).
N-Am in op yr r ole. Prepared according to the literature.21,22
Hydrazine monohydrate (82%, 0.85 mL, 14.4 mmol) was added
to a solution of 1-phthalimidopyrrole (2.35 g, 11.1 mmol) in
methanol (20.0 mL), and the reaction mixture was heated at
reflux for 1 h. After being cooled, the reaction was treated with
acetic acid (90%, 0.30 mL), and then the mixture was refluxed
for 15 min. The reaction was filtered and the methanol
removed by distillation through a Vigreux’s column. The crude
product was treated with excess of aqueous 40% NaOH and
extracted with ether. The ether was removed by distillation,
and the N-aminopyrrole was purified by distillation under
vacuum (78 °C, 12 mmHg) (0.59 g, 65%).
Exp er im en ta l Section
Gen er a l P r oced u r es. Melting points were determined by
DSC on a SEIKO DSC 220C connected to a Model SSC5200H
Disk Station. Thermograms (sample size 0.003-0.010 g) were
recorded at the scanning rate of 2.0 °C min-1. Unless otherwise
stated, column chromatography was performed on silica gel
(Merck 60, 70-230 mesh). The Rf values were measured on
aluminum backed TLC plates of silica gel 60 F254 (Merck, 0.2
mm) with the indicated eluent. HF/6-31G** ab initio calcula-
tions19 were carried out through the Spartan 5.1.3 package
running on a Silicon Graphics O2 workstation. NMR spectra
were recorded on a Bruker DRX 400 (9.4 T, 400.13 MHz for
1H, 61.42 MHz for 2H, 100.62 MHz for 13C and 40.56 MHz for
15N) spectrometer. Chemical shifts (δ in ppm) are given from
internal CHCl3 (7.26) for 1H NMR, CDCl3 (7.25) for 2H NMR,
13CDCl3 (77.0) for 13C NMR and external nitromethane for 15N
NMR. Coupling constants (J in Hz) are accurate to ( 0.2 Hz
for 1H and ( 0.6 Hz for 13C and 15N. Mass spectra (HRMS) at
70 eV using electron impact mode was performed on a VG
AUTOSPEC spectrometer by “Laboratorio de Espectrometr´ıa
de Masas-UAM, Madrid.”
[
15N2]-Am in op yr r ole. Obtained as described for N-ami-
nopyrrole using labeled 1-phthalimidopyrrole (0.90 g, 4.21
1
mmol) to yield 0.14 g (40%). H NMR (CDCl3) δ 6.70 (H2/H5,
2
3
m, 2H, J N-H ) 2.3), 6.06 (H3/H4, m, 2H, J H-N ) 6.4), 4.84
(NH2, d, 2H, J N-H ) 69.7); 13C NMR (CDCl3) δ 121.9 (C2/C5,
1
1J ) 185.9, 1J C-N ) 14.7, 2J C-N ) 2.1), 106.2 (C3/C4, 1J ) 171.2,
2J C-N ) 5.6); 15N NMR (CDCl3) δ -214.1 (N1, J N-N ) 4.9),
1
-309.5 (NH2).
4-Am in o-1,2,4-tr ia zole. A solution of formic acid (1.00 mL,
25.9 mmol), hydrazine sulfate (5.00 g, 38.4 mmol), and
potassium bicarbonate (7.70 g, 76.9 mmol) in water (25.0 mL)
was slowly heated until 200 °C, to permit the continuous
elimination of water and excess hydrazine by distillation. Once
elimination was completed, the reaction mixture was heated
at 200 °C for additional 6 h. After cooling, the amorphous crude
solid was washed with ethanol. The filtered solution was
concentrated to afford a crystalline product which was purified
by recrystallization from ethanol to give 4-amino-1,2,4-triazole
(0.85 g, 39%). mp 83.2 °C; lit. mp 84-86 °C.23 1H NMR (DMSO-
d6) δ 8.37 (s, 2H), 6.19 (s, 2H); 13C NMR (DMSO-d6) δ 144.1.
Rea gen ts. The following labeled compounds were pur-
chased from Chemotrade: [15N]-aniline (95% 15N) and [15N2]-
hydrazine sulfate (95% 15N).
N-Am in op h th a lim id e. Prepared according to the litera-
ture20,21 to test the method before using it for the labeled
compound because it uses hydrazine hydrate (82% or 96%)
instead of hydrazine sulfate. To a solution of phthalimide (3.00
g, 20.4 mmol) in ethanol (30 mL) was added a solution of
potassium bicarbonate (4.90 g, 48.9 mmol) and hydrazine
sulfate (3.20 g, 24.6 mmol) in water (10.0 mL). The reaction
was stirred for 2 min at room temperature before heating at
reflux for 8 min. After water (14.0 mL) was added, the mixture
was poured into water (50.0 mL). The N-aminophthalimide
crystallized after 20 min in an ice bath, collected by filtration,
and washed with water, and the white needles were dried
under vacuum to yield 1.89 g, 57%. mp 196.5 °C (decomposes
at 199.0 °C), lit. mp 200-205 °C.21
[
15N4]4-Am in o-1,2,4-tr ia zole. By the same procedure used
for the nonlabeled compound and 15N2-hydrazine sulfate (5.00
g, 37.9 mmol) to give [15N4]4-amino-1,2,4-triazole (1.09 g, 48%).
mp 83.2 °C. 1H NMR (CDCl3): δ ) 8.22 (m, 2H), 4.97 (dd, 2H;
1J N-H ) 72.0, J N-H ) 0.7); 13C NMR (CD3OD) δ 146.1 (1J C-N
2
) 13.1); 15N NMR (CDCl3) δ -319.7 (NH2, 1J N-N ) 5.9), -203.7
(N4), -65.0 (N1/N2).
N,N-Dim eth ylfor m a m id e-Dim eth yl Su lfa te Com p lex
(8). According to Hafner et al. procedure,24 dimethyl sulfate
(1.80 mL, 18.9 mmol) was added slowly to a solution of
dimethylformamide (1.40 mL, 19.0 mmol) at 50-60 °C, under
argon atmosphere. After the addition was completed, the
mixture was heated for 2 h at 70-80 °C. Finally, a yellow oil
was obtained in 97% yield.
[
15N2]-N-Am in op h th a lim id e. Following the above method
using [15N2]-hydrazine sulfate (3.00 g, 22.7 mmol) to yield 1.60
g, 52%. 1H NMR (CDCl3) δ 7.85 (m, 2H), 7.73 (m, 2H), 4.15
6-(Dim eth yla m in o)fu lven e (9). The dimethylformamide-
dimethyl sulfate complex (8) (3.44 g, 17.3 mmol) was slowly
added to a solution of cyclopentadienylthallium (8.30 g, 30.8
mmol) in THF (40.0 mL) at -10 °C, under argon atmosphere.
During the addition, the temperature was kept below -5 °C.
After the addition was completed, the mixture was stirred at
20 °C for 2 h. The solution was filtered from the precipitate,
which was washed with THF, and the combined THF solutions
were concentrated. The crude product, after treatment with
activated carbon, is crystallized from cyclohexane to yield 1.35
g (64%) of yellow crystals. mp ) 68 °C, lit. mp 67-68 °C.24 1H
NMR (CDCl3) δ 7.23 (s, H2), 6.62 (m, H7, ∑nJ ) 8.4), 6.56 (m,
H6, ∑nJ ) 10.1), 6.44 (m, H5, ∑nJ ) 8.6), 6.35 (m, H4, ∑nJ )
8.4), 3.29 (s, CH3); 13C NMR (CDCl3) δ 148.7 (C2), 125.3 (C6),
124.5 (C5), 119.6 (C4), 116.9 (C3), 114.0 (C7), 30.4 (CH3).
N-(Dich lor op h osp h in a t em et h ylen e)-N-m et h ylm et h -
a n a m m on iu m Ch lor id e (10). A solution of phosphorus
oxychloride (0.65 mL, 6.97 mmol) in diethyl ether (2.50 mL)
at room temperature, under argon atmosphere, was added
(dd, 2H, J N-H ) 69.9, J N-H ) 0.8); 13C NMR (CDCl3) δ 166.6
1
2
(1J C-N ) 13.8), 134.3, 130.3 (2J C-N ) 9.7), 123.5. 15N NMR
1
(CDCl3) δ -210.6 (d, J N-N ) 6.1), -331.6.
1-P h th alim idopyr r ole. Prepared according to references.21,22
A solution of N-aminophthalimide (2.50 g, 15.4 mmol) and 2,5-
dimethoxytetrahydrofuran (2.5 mL, 19.3 mmol) in dry dioxane
(25.0 mL) was heated at reflux until a yellow solution was
obtained. Maintaining the heating, 5 N HCl (2.50 mL) was
carefully added, and the yellow solution became a dark
solution. The mixture was cooled, and the precipitate was
filtered and washed with a 1:3 mixture dioxane-water to yield
2.45 g (75%) of 1-phthalimidopyrrole. mp 217.1 °C; lit. mp
218.5 °C.20
[
15N2]-1-P h th a lim id op yr r ole. Following the same proce-
dure described for 1-phthalimidopyrrole and using [15N]-
(19) Ditchfield, R.; Hehre, W. J . Pople, J . A. J . Chem. Phys. 1971,
54, 724.
(20) Drew, H. D. K.; Hatt, H. H. J . Chem. Soc. 1937, 16.
(21) Flitsch, W.; Kra¨mer, U.; Zimmermann, H. Chem. Ber. 1969,
102, 3268.
(23) Herbst, R. M.; Garrison, J . A. J . Org. Chem. 1953, 18, 872.
(24) Hafner, K.; Vo¨pel, K. H.; Ploss, G.; Ko¨nig, C. Org. Synth. 1967,
47, 52.
(22) Flitsch, W.; Lu¨ttig, F.-J . Ann. Chem. 1987, 893.

1468 J . Org. Chem., Vol. 67, No. 5, 2002
Sanz et al.
slowly to a solution of DMF (1.10 mL, 15.0 mmol) in diethyl
ether (3.00 mL). After addition, the mixture was stirred for 2
h. A yellow oil was obtained in 94% yield. lit. quantitative
yield.25
sample tube. A small amount of NaH was added. When
observed by 1H NMR that the anion was formed, iodomethane
(3.0 µL, 0.05 mmol) was added.
2
Anion: 1H NMR (THF-d8): δ ) 8.82 (dd, H2/H8, J N-H
)
6-Dim et h yla m in ofu lven e-1-N,N-d im et h yla ld im m on i-
u m P er ch lor a te (11). A solution of 10 (3.22 g, 14.2 mmol) in
THF (40.0 mL) was carefully added to a solution of 6-(dim-
ethylamino)fulvene (9) (2.63 g, 21.7 mmol) in THF (60.0 mL)
at -60 °C. The solution becomes red from which yellow crystals
grew. Afterward, these crystals were dissolved in ethanol (5.00
mL) at -50 °C, and a saturated NaClO4 solution (1.50 g
NaClO4/20.0 mL ethanol) was slowly added. Finally, the
solution was filtered, and the precipitate was washed with
ethanol. Colorless needles of 11 were obtained, yield 3.17 g,
72%. mp 220.8 °C (it decomposes at 240.9 °C), lit. mp 235-
237 °C.26 1H NMR (DMSO-d6) δ 8.90 (s, H2/H8), 7.30 (d, H4/
2.9, 5J ) 1.1), 7.20 (t, Hm), 7.06 (d, Ho), 6.91 (t, Hp), 6.53 (dd,
H4/H6, 3J H5-H4/H6 ) 3.5, 5J ) 1.1), 5.99 (t, H5); 15N NMR (THF-
d8): δ ) -113.0 (N1/N9).
(12-15N2): 1H NMR (THF-d8): δ ) 9.88 (br s, H2), 8.48 (d,
H8, 2J H-N ) 3.3), 7.44 (m, Hm′/Ho′), 7.26 (t, Hm), 7.24 (t, Hp′),
7.09 (d, Ho), 7.04 (t, Hp), 6.82 (br, H4), 6.74 (m, H6), 6.38 (br
2
m, H5), 3.72 (d, CH3, J Me-N ) 1.4); 13C NMR (THF-d8): δ )
158.1 (C8, 1J ) 153.2, 1J C-N ) 6.4), 149.6 (C2, 1J ) 174.3, 1J C-N
1
3
1
) 19.0), 134.5 (C6, J ) 161.4, J C-N ) 3.5), 130.5 (Cm′, J )
1
1
162.6), 129.5 (Cm, J ) 159.3), 126.6 (Cp′, J ) 161.8), 125.0
(Cp, 1J ) 158.0), 124.5 (C5, 1J ) 164.8), 124.0 (C4, 1J ) 153.7),
122.3 (Co′, 1J ) 159.1), 121.4 (Co, 1J ) 160.1, J C-N ) 2.8),
2
3
41.3 (CH3); 15N NMR (THF-d8): δ ) -256.0 (N1), -77.0 (N9).
H6, J H4/H6-H5 ) 3.5), 6.76 (t, H5), 3.65(s, CH3), 3.45 (s, CH3);
1
13C NMR (DMSO-d6) δ 154.6 (C2/C8, J ) 166.9), 128.3 (C4/
N-{[5-[(Dim eth ylam in o)m eth ylen e]-1,3-cyclopen tadien -
1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (13). A solution of
11 (1.00 g, 3.21 mmol) in EtOH (20.0 mL) was refluxed with
4-amino-1,2,4-triazole (0.55 g, 6.54 mmol) for 21 h. The solvent
was evaporated, and the crude was purified by column
chromatography (1:3 EtOH-chloroform) to afford 13, yield 0.44
g, 64%. mp 201.6 °C (decomposes at 207.4 °C); 1H NMR (CDCl3)
δ 8.79 (br s, H2), 8.45 (s, H8), 8.40 (s, H2′/H5′), 6.96 (m, H4),
C6, 1J ) 168.6), 125.3 (C5, 1J ) 167.0), 118.6 (C3/C7), 48.5
1
1
(CH3, J ) 140.9), 42.1 (CH3, J ) 138.1); 15N NMR (DMSO-
d6) δ -237.7 (N1/N9).
N,N′-Dip h en yl-6-a m in ofu lven e-1-a ld im in e/N-{[5-[(p h e-
n ylam in o)m eth ylen e]-1,3-cyclopen tadien -1-yl]m eth ylen e}-
ben zen a m in e (1). Using the procedure described in ref 15.
A solution of 11 (0.50 g, 1.61 mmol) in EtOH (5.00 mL) was
refluxed with aniline (0.37 mL, 4.06 mmol) for 1 h. The solvent
was evaporated, and the crude was purified by column
chromatography (1:10 AcOEt-hexane) to afford the N,N′-
diphenyl-6-aminofulvene-1-aldimine, yield 0.26 g, 59%. mp
97.7 °C; lit. mp 100 °C;15 1H NMR (CDCl3) δ 15.59 (t, H10,
4
3
6.84 (dd, H6, J H6-H4 ) 1.6), 6.50 (ddd, H5, J H5-H6 ) 3.2,
5
3J H5-H4 ) 4.6, J H5-H2 ) 0.9), 3.45 (s, CH3), 3.35 (s, CH3); 13C
1
3
1
NMR (CDCl3) δ 157.5 (C8, J ) 156.5, J ) 3.4), 152.9 (C2, J
) 170.1), 138.3 (C2′/C5′, 1J ) 211.7, 3J ) 4.0), 134.2 (C6, 1J )
165.2), 125.0 (C4, 1J ) 166.2,), 124.7 (C7), 123.0 (C5, 1J )
3
3
3J H10-H2/H8 ) 6.9), 8.29 (d, H2/H8), 7.42 (t, Hm, J ) 7.5, J )
8.2), 7.28 (d, Ho), 7.20 (t, Hp), 7.08 (d, H4/H6), 6.48 (t, H5,
3J H5-H4/H6 ) 3.6); 13C NMR (CDCl3) δ 150.8 (C2/C8, 1J ) 160.5),
145.4 (Ci, 3J ) 3J ) 7.7), 134.8 (C4/C6, 1J ) 164.2, ∑nJ ) 17.0),
129.7 (Cm, 1J ) 160.7, 3J ) 7.7), 125.0 (Cp, 1J ) 158.9), 122.3
(C3/C7, ∑nJ ) 34.4), 121.1 (C5, 1J ) 166.6, 2J ) 2J ) 4.0),
119.3 (Co, 1J ) 159.4, 3J ) 3J ) 6.7); 15N NMR (CDCl3) δ
-168.2 (N1/N9).
2
2
1
167.0, J ) J ) 3.6), 113.1 (C3), 48.2 (CH3, J ) 140.3), 41.0
(CH3, 1J ) 140.5); 15N NMR (CDCl3) δ -268.2 (N1), -162.6
(N1′), -103.6 (N9), -66.5 (N3′/N4′). Elemental analysis calcd
for C11H13N5: C 61.38, H 6.09, N 32.54; found: C 61.59, H
6.18, N 32.42.
N-{[5-[(P h en yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (2). A solution of 13
(0.30 g, 1.40 mmol) in EtOH (15.0 mL) was refluxed with
aniline (0.15 mL, 1.69 mmol) for 6 h 20 min. The solvent was
evaporated, and the crude was purified by column chroma-
tography with the following eluents: 5:1 AcOEt-hexane, (1)
[Rf 0.88 (10:1 CHCl3-EtOH)] and aniline [Rf 0.67 (10:1 CHCl3-
EtOH)]; AcOEt, (2) [Rf 0.46 (10:1 CHCl3-EtOH)]; 10:1 CHCl3-
EtOH, (13) [Rf 0.24 (10:1 CHCl3-EtOH)]. Yield in (2) 0.33 g,
89%, mp 213.9 °C (decomposes);1H NMR (CDCl3) δ 12.77 (d,
15N,15N′-Dip h en yl-6-a m in ofu lven e-1-a ld im in e/[15N2]-
{[5-[(p h en yla m in o) m eth ylen e]-1,3-cyclop en ta d ien -1-yl]-
m et h ylen e}[15N]b en zen a m in e (1-15N2). A solution of 11
(2.20 g, 7.07 mmol) in EtOH (40.0 mL) was refluxed with
labeled aniline (1.71 g, 18.2 mmol) for 4 h. The solvent was
evaporated, and the crude was purified by column chroma-
tography (1:20 AcOEt-hexane) to afford 15N,15N′-diphenyl-6-
1
3
aminofulvene-1-aldimine, yield 1.07 g, 56%. H NMR (CDCl3)
H10, J H10-H2 ) 13.9), 8.54 (br s, H8), 8.51 (s, H2′/H5′), 8.07
1
3
5
δ 15.63 (tt, H10, J N1/N9-H10 ) 41.0, J H10-H2/H8 ) 6.9), 8.29 (d,
(dd, H2, J H2-H6 ) 0.9), 7.44 (t, Hm), 7.26 (m, H6), 7.24 (d,
3
3
4
5
H2/H8), 7.42 (t, Hm, J ) 7.5, J ) 8.2), 7.28 (d, Ho), 7.20 (t,
Ho), 7.20 (t, Hp), 7.08 (ddd, H4, J H4-H6 ) 1.9, J H4-H8 ) 0.7),
Hp), 7.08 (d, H4/H6), 6.48 (t, H5, J H5-H4/H6 ) 3.6); 13C NMR
3
6.53 (dd, H5, J H5-H6 ) 3.2, J H5-H4 ) 4.3); 13C NMR (CDCl3)
3
3
1
1
3
δ 157.9 (C8, 1J ) 159.4, 3J ) 4.0), 143.9 (C2, 1J ) 166.7), 141.4
(CDCl3) δ ) 150.8 (C2/C8, J ) 160.5, J C-N ) 12.4, J C-N
+
+
4J C-N ) 1.5), 145.4 (Ci, J ) J ) 7.7, J C-N ) 10.7, J C-N
3
3
1
3
1
1
(C6, J ) 159.4), 139.0 (Ci), 138.4 (C2′/C5′, J ) 211.1), 135.9
(C4, 1J ) 166.4), 130.2 (Cm, 1J ) 162.1), 125.8 (Cp, 1J ) 163.8),
122.3 (C5, 1J )168.7), 120.0 (C7), 117.4 (Co, 1J ) 155.3), 116.9
(C3); 15N NMR (CDCl3) δ -238.1 (N1), -167.7 (N1′), -121.0
(N9), -64.4 (N3′/N4′). Elemental analysis calcd for C15H13N5:
C 68.42, H 4.98, N 26.60; found: C 68.60, H 4.96, N 26.52.
6J C-N ) 0.9), 134.8 (C4/C6, 1J ) 164.2), 129.7 (Cm, 1J ) 160.7,
3J ) 7.7), 125.0 (Cp, J ) 158.9), 122.3 (C3/C7), 121.1 (C5, J
1
1
2
2
1
3
3
) 166.6, J ) J ) 4.0), 119.3 (Co, J ) 159.4, J ) J ) 6.7);
15N NMR (CDCl3) δ -168.2 (N1/N9,
J
) 10.6). The
N1-H10‚‚‚N9
2h
deuterated compound (1-15N2-2H1) was prepared directly in the
NMR sample tube by agitating the CDCl3 solution with D2O:
only H10 exchange. 1H NMR (CDCl3 + D2O): δ ) 8.30 (s, H2/
H8), 7.44 (t, Hm), 7.37 (d, Ho), 7.24 (t, Hp), 7.10 (d, H4/H6),
6.52 (t, H5, 3J ) 3.7); 13C NMR (CDCl3 + D2O): δ ) 150.4
[
15N4]-{[5-[(Dim eth yla m in o)m eth ylen e]-1,3-cyclop en ta -
d ien -1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (13-15N4). A
solution of 11 (1.00 g, 3.21 mmol) in EtOH (20.0 mL) was
refluxed with [15N4]-4-amino-1,2,4-triazole (0.57 g, 6.48 mmol)
for 21 h. The solvent was evaporated, and the crude was
purified by column chromatography (1:3 EtOH-CHCl3) to
1
1
(C2/C8, J C-N ) 9.9), 145.4 (Ci, J C-N ) 2.4), 134.9 (C4/C6),
129.6 (Cm), 124.9 (Cp), 122.2 (C3/C7), 121.1 (C5), 119.1 (Co);
15N NMR (CDCl3+ D2O): δ ) -168.6 (t, N1/N9, J N1/N9-D
)
1
afford 13-15N4, yield 0.42 g, 60%. H NMR (CDCl3) δ 8.81 (br
1
2
6.1). H NMR (CDCl3+ D2O): δ ) 15.28 (D10).
2
3
5
s, H2), 8.47 (ddd, H8, J H8-N9 ) 2.2, J H8-N1′ ) 8.1, J H8-H4
)
)
15N2]-{[5-[(Meth ylp h en yla m in o)m eth ylen e]-1,3-cyclo-
4
[
0.6), 8.42 (m, H2′/H5′), 6.97 (dd, H4), 6.86 (dd, H6, J H6-H4
p en ta d ien -1-yl]m eth ylen e}-[15N]ben zen a m in e (12-15N2).
A solution of [15N2]-{[5-[(phenylamino)methylene]-1,3-cyclo-
pentadien-1-yl]methylene}[15N]benzenamine (1-15N2) (10.0 mg,
0.04 mmol) in THF-d8 (0.50 mL) was poured into a NMR
1.6), 6.52 (ddd, H5, 3J H5-H6 ) 3.2, 3J H5-H4 ) 4.6, 5J H5-H2 ) 0.9),
3.46 (s, CH3), 3.36 (s, CH3); 13C NMR (CDCl3) δ 157.5 (C8, J
1
3
1
4
) 156.5, J ) 3.4), 152.9 (C2, J ) 170.1, J C-N ) 3.8), 138.3
1
3
1
1
(C2′/C5′, J ) 211.7, J ) 4.0, J C-N1′ ) 13.5), 134.2 (C6, J )
3
1
3
165.2, J C-N ) 3.9), 125.0 (C4, J ) 166.2), 124.7 (C7, J C-N
)
2
1
2
2
6.9, J C-N ) 5.2), 123.0 (C5, J ) 167.0, J ) J ) 3.6), 113.1
(25) Bredereck, H.; Gompper, R.; Klemm, K.; Rempfer, H. Chem.
Ber. 1959, 92, 837.
(26) Hafner, K.; Vo¨pel, K. H.; Ploss, G.; Ko¨nig, C. Ann. Chem. 1963,
661, 52.
(C3), 48.2 (CH3, J ) 140.3), 41.0 (CH3, J ) 140.5); 15N NMR
1
1
1
(CDCl3) δ -268.2 (N1), -162.6 (N1′, J N1′-N9 ) 13.8), -103.6
1
(N9, J N9-N1′ ) 13.8), -66.5 (N3′/N4′).

Tautomerism of 6-Aminofulvene-1-aldimines
J . Org. Chem., Vol. 67, No. 5, 2002 1469
N-{[5-[(P h en yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (2-15N4). A solution
of 13-15N4 (0.25 g, 1.14 mmol) in EtOH (15.0 mL) was refluxed
with aniline (0.13 mL, 1.43 mmol) for 7 h. The solvent was
evaporated, and the crude was purified by column chroma-
tography with the following eluents: 5:1 AcOEt-hexane, (1)
and aniline; AcOEt, (2-15N4); 10:1 CHCl3-EtOH, (13-15N4);.
Yield in (2-15N4) 0.21 g, 68%. 1H NMR (CDCl3) δ 12.77 (d, H10,
solution of N-{[5-[(phenylamino)methylene]-1,3-cyclopenta-
dien-1-yl]methylene}-1,2,4-triazole-4-amine (2-15N5) (10.0 mg,
0.04 mmol) in THF (0.75 mL) was poured into a NMR sample
tube. A small amount of NaH was added. When observed by
1H NMR that the anion was formed, iodomethane (3.0 µL, 0.05
mmol) was added.
2
Anion: 1H NMR (THF-d8): δ ) 9.39 (d, H8, J N-H ) 7.3),
8.46 (m, H2, H2′/H5′), 7.16 (t, Hm), 6.99 (d, Ho), 6.93 (t, H5,
2
3
3
3J H10-H2 ) 13.9), 8.54 (ddd, H8, J H8-N9 ) 2.4, J H8-N1′ ) 7.3),
3J H5-H6 ) J H5-H4 ) 3.5), 6.87 (t, Hp), 6.69 (m, H6), 6.42 (m,
4h
5
1
8.51 (m, H2′/H5′), 8.07 (dd, H2,
J
) 0.9, J H6-H2 ) 0.9),
H4); 15N NMR (THF-d8): δ ) -155.4 (N1′, J N9-N1′ ) 14.6),
H2-N9
1
7.44 (t, Hm), 7.26 (m, H6), 7.24 (d, Ho), 7.20 (t, Hp), 7.08 (ddd,
-123.9 (N9, J N9-N1′ ) 14.6), -103.3 (N1), -73.5 (N3′/N4′).
4
5
3
H4, J H4-H6 ) 1.9, J H4-H8 ) 0.7), 6.53 (dd, H5, J H5-H6 ) 3.2,
3J H5-H4 ) 4.3); 13C NMR (CDCl3) δ 157.9 (C8, 1J ) 159.4, 3J )
4.0, 1J C-N ) 4.8), 143.9 (C2, 1J ) 166.7), 141.4 (C6, 1J ) 159.4,
(14-15N5): 1H NMR (THF-d8): δ ) 9.22 (s, H2), 8.77 (dd,
2
3
H8, J H8-N9 ) 2.3, J H8-N1′ ) 8.0), 8.67 (m, H2′/H5′), 3.75 (d,
CH3, J CH3-N ) 1.5); 15N NMR (THF-d8): δ ) -254.2 (N1),
-163.6 (N1′), -100.2 (N9), -63.5 (N3′/N4′).
2
3J C-N ) 4.8), 139.0 (Ci), 138.4 (C2′/C5′, J ) 211.1, J C-N1′
)
1
1
12.3), 135.9 (C4, 1J ) 166.4), 130.2 (Cm, 1J ) 162.1), 125.8
N-{[5-[(P yr r ol-1-yla m in o)m et h ylen e]-1,3-cyclop en t a -
d ien -1-yl]m eth ylen e}p yr r ole-1-a m in e (4) a n d N-{[5-[(Di-
methylamine)methylene]-1,3-cyclopentadien-1-yl]methylene}-
p yr r ole-1-a m in e (15). A solution of 11 (0.82 g, 2.64 mmol)
in EtOH (20.0 mL) was refluxed with N-aminopyrrole (0.54 g,
6.59 mmol) for 3 h 45 min. The solvent was evaporated, and
the crude was purified by column chromatography (1:10
CHCl3-hexane) to afford (4) [Rf ) 0.62 (1:3 AcOEt-hexane)]
(0.053 g, 8%) and a mixture of 15 and N-aminopyrrole [Rf )
0.17 (1:3 AcOEt-hexane)]; this mixture was chromatographed
over aluminum oxide (1:10 AcOEt-hexane) to afford pure
15 [Rf ) 0.21 (1:3 AcOEt-hexane)], yield 0.14 g, 25%. mp
95.1 °C.
(Cp, 1J ) 163.8), 122.3 (C5, 1J ) 168.7), 120.0 (C7, J C-N
)
2
5.2, J C-N ) 8.5), 117.4 (Co, J ) 155.3), 116.9 (C3); 15N NMR
3
1
1
(CDCl3) δ -238.1 (N1), -167.7 (N1′, J N9-N1′ ) 11.8), -121.0
1
(N9, J N9-N1′ ) 11.8), -64.4 (N3′/N4′).
N-{[5-[(P h en yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (2-15N). A solution
of 13 (0.15 g, 0.70 mmol) in EtOH (20.0 mL) was refluxed with
labeled aniline (0.08 g, 0.85 mmol) for 6 h 45 min. The solvent
was evaporated, and the crude was purified by column
chromatography with the following eluents: 5:1 AcOEt-
hexane, (1-15N2) and [15N]-aniline); AcOEt, (2-15N); 10:1 CHCl3-
1
EtOH, (13). Yield in (2-15N) 0.06 g, 33%. H NMR (CDCl3) δ
1
3
12.76 (dd, H10, J N1-H10 ) 88.6, J H10-H2 ) 13.9), 8.54 (br s,
H8), 8.51 (s, H2′/H5′), 8.06 (dd, H2, 5J H2-H6 ) 0.9), 7.44 (t, Hm),
7.26 (m, H6), 7.24 (m, Ho), 7.20 (m, Hp), 7.08 (ddd, H4, 4J H4-H6
(15): 1H NMR (CDCl3) δ 8.90 (br s, H2), 8.49 (s, H8), 7.07
4
(m, H2′/H5′), 6.85 (dd, H4), 6.73 (dd, H6, J H6-H4 ) 1.6), 6.49
3
3
5
(ddd, H5, J H5-H6 ) 3.0, J H5-H4 ) 4.7, J H5-H2 ) 0.9), 6.21 (m,
H3′/H4′), 3.39 (br s, CH3), 3.34 (br s, CH3); 13C NMR (CDCl3)
δ 152.4 (C2, 1J ) 168.9), 149.4 (C8, 1J ) 156.0, 3J ) 3.3), 130.3
(C6, 1J ) 161.1), 126.9 (C7), 122.6 (C5, 1J ) 165.0), 121.9 (C4,
1J ) 165.6), 115.3 (C2′/C5′, 1J ) 185.7), 112.9 (C3), 107.1 (C3′/
C4′, 1J ) 171.7), 48.2 (CH3, 1J ) 136.9), 41.0 (CH3, 1J ) 140.8);
15N NMR (CDCl3) δ -272.7 (N1), -171.8 (N1′), -83.5 (N9).
Elemental analysis calcd for C13H15N3: C 73.21, H 7.09, N
19.70; found: C 72.70, H 7.26, N 19.68.
5
3
3
) 1.9, J H4-H8 ) 0.7), 6.52 (dd, H5, J H5-H6 ) 3.2, J H5-H4
)
4.3); 13C NMR (CDCl3) δ 157.9 (C8, 1J ) 159.4, 3J ) 4.0), 143.9
1
1
1
(C2, J ) 166.7, J C-N ) 15.9), 141.4 (C6, J ) 159.4), 139.0
1
1
1
(Ci, J C-N ) 14.8), 138.4 (C2′/C5′, J ) 211.1), 135.9 (C4, J )
166.4, 3J C-N ) 3.5), 130.2 (Cm, 1J ) 162.1, 3J C-N ) 1.9), 125.8
1
1
(Cp, J ) 163.8), 122.3 (C5, J )168.7), 120.0 (C7), 117.4 (Co,
1J ) 155.3), 116.9 (C3); 15N NMR (CDCl3) δ -238.1 (N1),
-167.7 (N1′), -121.0 (N9), -64.4 (N3′/N4′).
3
N-{[5-[(P h en yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (2-15N5). A solution
of 13-15N4 (0.35 g, 1.60 mmol) in EtOH (18.0 mL) was refluxed
with labeled aniline (0.19 g, 2.00 mmol) for 7 h. The solvent
was evaporated, and the crude was purified by column
chromatography with the following eluents: 5:1 AcOEt-
hexane, (1-15N2) and [15N]-aniline, AcOEt, (2-15N5), 10:1 CHCl3-
EtOH, (13-15N4). Yield in (2-15N5) 0.21 g, 49%. 1H NMR (CDCl3)
(4a ): 1H NMR (CDCl3) δ 13.52 (t, H10, J H10-H2/H8 ) 5.7),
8.09 (d, H2/H8), 6.97 (d, H4/H6), 6.93 (m, H2′/H5′), 6.49 (t,
3
H5, J H5-H4/H6 ) 3.7), 6.24 (m, H3′/H4′); 13C NMR (CDCl3) δ
148.7 (C2/C8, 1J ) 164.5), 135.2 (C4/C6, 1J ) 164.5), 122.4
(C5, 1J ) 166.9), 117.9 (C3/C7), 117.9 (C2′/C5′, 1J ) 188.2),
1
108.2 (C3′/C4′, J ) 171.8); 15N NMR (CDCl3) δ -193.3 (N1/
N9), -169.8 (N1′). The corresponding 10-deuterated deriva-
tive: 2H NMR (CDCl3): δ ) 13.30 (D10).
1
3
1h
δ 12.77 (ddd, H10, J N1-H10 ) 88.6, J H10-H2 ) 13.9,
J
(4c): 1H NMR (CDCl3) δ 8.64 (s, H2), 8.61 (s, H8), 7.18 (m,
H2′/H5′or H2′′/H5′′), 7.15 (m, H2′/H5′ or H2′′/H5′′), 7.09 (d, H6),
6.64 (d, H5, 3J H5-H6 ) 5.4), 6.31 (m, H3′/H4′ or H3′′/H4′′), 6.30
(m, H3′/H4′ or H3′′/H4′′), 3.68 (br s, H4); 13C NMR (CDCl3) δ
N9‚‚‚H10
2
3
) 4.4), 8.54 (ddd, H8, J H8-N9 ) 2.4, J H8-N1′ ) 7.3), 8.51 (m,
4h
H2′/H5′), 8.06 (td, H2,
J
) 5J H2-H6 ) 0.9), 7.44 (t, Hm),
H2-N9
7.26 (ddd, H6), 7.24 (m,Ho), 7.20 (m, Hp), 7.08 (ddd, H4, 4J H6-H4
5
3
3
1
1
1
) 1.9, J H4-H8 ) 0.7), 6.53 (dd, H5, J H5-H6 ) 3.2, J H5-H4
)
141.0 (C2, J ) 159.5), 139.7 (C8, J ) 160.5), 135.9 (C5, J )
4.3); 13C NMR (CDCl3) δ 157.9 (C8, 1J ) 159.4, 3J ) 4.0, 1J C-N
169.3), 131.4 (C6, 1J ) 169.3), 116.1 (C2′/C5′ or C2′′/C5′′, 1J )
1
1
1
1
) 4.8), 143.9 (C2, J ) 166.7, J C-N ) 15.9), 141.4 (C6, J )
187.8), 116.0 (C2′/C5′ or C2′′/C5′′, J ) 187.5), 109.3 (C3′/C4′
159.4, 3J C-N ) 4.8), 139.0 (Ci, 1J C-N ) 14.8), 138.4 (C2′/C5′, 1J
or C3′′/C4′′, 1J ) 171.8), 109.0 (C3′/C4′ or C3′′/C4′′, 1J ) 171.8),
42.3 (C4, 1J ) 124.3); 15N NMR (CDCl3) δ -172.5 (N1′ and
N1′′), -60.4 (N1), -53.2 (N9).
1
1
3
) 211.1, J C-N1′ ) 12.3), 135.9 (C4, J ) 166.4, J C-N ) 3.5),
130.2 (Cm, 1J ) 162.1, J C-N ) 1.9), 125.8 (Cp, 1J ) 163.8),
3
122.3 (C5, 1J )168.7), 120.0 (C7, J C-N ) 5.2, J C-N ) 8.5),
117.4 (Co, 1J ) 155.3), 116.9 (C3); 15N NMR (CDCl3) δ -238.1
(N1, 2hJ N1-H10‚‚‚N9 ) 8.6), -167.7 (N1′, 1J N9-N1′ ) 11.8), -121.0
N-{[5-[(P h en yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
1-yl]m eth ylen e}p yr r ole-1-a m in e (3). A solution of 15 (0.077
g, 0.361 mmol) in EtOH (4.00 mL) was refluxed with aniline
(0.04 mL, 0.43 mmol) for 1 h 25 min. The solvent was
evaporated, and the crude was purified by column chroma-
tography (1:20 AcOEt-hexane) to afford 3 [Rf ) 0.56 (1:3
2
3
2h
1
(N9,
J
) 8.6, J N9-N1′ ) 11.8), -64.4 (N3′/N4′).
N1-H10‚‚‚N9
Compound (2-15N5-2H1) was prepared directly in the NMR
sample tube by agitating the CDCl3 solution with D2O: only
H10 exchange. The NMR data for the corresponding D10
deuterated derivative: 1H NMR (CDCl3 + D2O and a small
1
AcOEt-hexane)]; yield 0.082 g, 87%. mp 148.8 °C; H NMR
3
(CDCl3) δ 13.26 (br d, H10, J H10-H2 ) 13.5), 8.54 (br s, H8),
2
3
5
amount of CD3OD): δ ) 8.54 (dd, H8, J H8-N9 ) 2.5, J H8-N1′
) 7.3), 8.51 (m, H2′/H5′), 8.04 (s, H2), 7.44 (t, Hm), 7.40 (dd,
7.98 (dd, H2, J H2-H6 ) 1.0), 7.42 (m, Hm), 7.25 (m, Ho), 7.18
(m, Hp), 7.12 (m, H2′/H5′), 7.09 (ddd, H6), 6.91 (ddd, H4,
4
H6), 7.24 (m,Ho), 7.20 (m, Hp), 7.06 (dd, H4, J H4-H6 ) 1.8),
4J H4-H6 ) 1.9, 5J H4-H8 ) 0.6), 6.46 (dd, H5, 3J H5-H6 ) 3.0, 3J H5-H4
6.50 (dd, H5, 3J H5-H6 ) 3.3, 3J H5-H4 ) 4.2); 15N NMR (CDCl3 +
) 4.4), 6.29 (m, H3′/H4′); 13C NMR (CDCl3) δ 149.6 (C8, J )
1
1
D2O and a small amount of CD3OD): δ ) -239.3 (N1, J N1-D
158.8, 3J ) 3.7), 142.8 (C2, 1J )166.6, 3J ) 2.3), 139.8 (Ci),
1
2d
1
1
1
) 13.2), -167.3 (N1′, J N9-N1′ ) 12.0), -120.9 (N9,
J
137.5 (C6, J )164.1), 132.1 (C4, J )166.5), 130.0 (Cm, J )
161.0), 124.8 (Cp, 1J ) 160.6), 122.2 (C7), 121.5 (C5, 1J ) 167.5,
N1-D‚‚‚N9
1
2
) 8.5, J N9-N1′ ) 11.9), -66.8 (N3′/N4′). H NMR (CDCl3): δ
) 12.65 (D10).
2J ) J ) 4.0), 117.2 (Co, J ) 158.1), 116.6 (C3), 115.3 (C2′/
C5′, J ) 186.3, J ) J ) 7.7, J ) 5.0), 108.0 (C3′/C4′, J )
172.4, 2J ) 3J ) 7.6, 2J ) 3.4); 15N NMR (CDCl3) δ -240.7
2
1
1
2
3
3
1
N-{[5-[(Meth ylp h en yla m in o)m eth ylen e]-1,3-cyclop en -
ta d ien -1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (14-15N5). A

1470 J . Org. Chem., Vol. 67, No. 5, 2002
Sanz et al.
(N1), -177.4 (N1′), -99.7 (N9). Elemental analysis calcd for
)164.1, 3J C-N ) 4.4), 132.1 (C4, 1J )166.5, 3J C-N ) 3.0), 130.0
1
3
1
C
17H15N3: C 78.13, H 5.79, N 16.08; found: C 77.90, H 5.86,
(Cm, J ) 161.0, J ) 8.0), 124.8 (Cp, J ) 160.6), 122.2 (C7,
3
N 15.92. The corresponding N-deuterated derivative has the
following NMR characteristics: 2H NMR (CDCl3 + D2O): δ )
13.15 (D10).
2J C-N ) 5.0, J C-N ) 8.2), 121.5 (C5, 1J ) 167.5, 2J ) 2J )
4.0), 117.2 (Co, 1J ) 158.1), 116.6 (C3), 115.3 (C2′/C5′, 1J )
186.3, 2J ) 3J ) 7.7, 3J ) 5.0, 1J C-N ) 14.7, 2J C-N ) 1.9), 108.0
1
2
2
2
[
15N4]-N-{[5-[(P yr r ol-1-yla m in o)m et h ylen e]-1,3-cyclo-
(C3′/C4′, J ) 172.4, J ) 3J ) 7.6, J ) 3.4, J C-N ) 5.6); 15
N
2h
p en ta d ien -1-yl]m eth ylen e}p yr r ole-1-a m in e (4-15N4) a n d
15N2]-N-{[5-[(Dim eth yla m in e)m eth ylen e]-1,3-cyclop en ta -
NMR (CDCl3) δ -240.7 (N1,
J
) 9.0), -177.4 (N1′,
N1-H10‚‚‚N9
[
1J N9-N1′ ) 10.3), -99.7 (N9). The corresponding N-deuterated
d ien -1-yl]m eth ylen e}p yr r ole-1-a m in e (15-15N2). A solution
of 11 (0.26 g, 0.84 mmol) in EtOH (6.50 mL) was refluxed with
[15N2]-aminopyrrole (0.14 g, 1.68 mmol) for 3 h 30 min. The
solvent was evaporated, and the crude was purified by column
chromatography (1:10 CHCl3-hexane) to afford (4-15N4) and a
mixture of 15-15N2 and [15N2]-aminopyrrole; this mixture was
chromatographed over aluminum oxide (1:10 AcOEt-hexane)
to afford pure 15-15N2; yield 0.098 g, 54%.
derivative has the following NMR characteristics: 1H NMR
2
3
(CDCl3 + D2O): δ ) 8.53 (dd, H8, J H8-N9 ) 2.8, J H8-N1′
)
6.9), 7.95 (s, H2), 7.41 (m, Hm), 7.24 (m, Ho), 7.18 (m, Hp),
7.13 (m, H2′/H5′, 2J H-N ) 0.9, 3J H-N ) 2.5), 7.09 (m, H6), 6.90
4
3
3
(dd, H4, J H4-H6 ) 1.9), 6.47 (dd, H5, J H5-H6 ) 3.0, J H5-H4
)
4.4), 6.31 (m, H3′/H4′, J H-N ) 6.1); 13C NMR (CDCl3 + D2O):
3
3
1
1
δ ) 149.5 (C8, J C-H ) 1.5, J C-N ) 6.2), 142.4 (C2, J C-N
)
1
3
15.7), 139.6 (Ci, J C-N ) 15.4), 137.6 (C6, J C-N ) 4.7), 132.1
3
3
(15-15N2): 1H NMR (CDCl3) δ 8.93 (br s, H2), 8.53 (dd, H8,
(C4, J C-N ) 2.9), 129.8 (Cm, J C-N ) 1.9), 124.7 (Cp), 122.2
2 3 2
3
2
2J H8-N9 ) 2.6, J H8-N1′ ) 7.7), 7.12 (m, H2′/H5′, J H2′/H5′-N1′
)
)
(C7, J C-N ) 4.9, J C-N ) 8.4), 121.4 (C5), 117.0 (Co, J C-N )
0.9, J
) 2.4), 6.89 (dd, H4), 6.77 (dd, H6, J H6-H4
1.7), 116.5 (C3, 2J C-N ) 1.6), 115.2 (C2′/C5′, 1J C-N ) 14.9, 2J C-N
3
4
H2′/H5′-N9
2
1.6), 6.53 (ddd, H5, 3J H5-H6 ) 3.0, 3J H5-H4 ) 4.7, 5J H5-H2 ) 0.9),
6.26 (m, H3′/H4′, 3J H3′/H4′-N1′ ) 5.9), 3.39 (s, CH3), 3.33 (s, CH3);
) 1.8), 107.9 (C3′/C4′, J C-N ) 5.6); 15N NMR (CDCl3 + D2O):
1
2d
δ ) -242.1 (N1, J N1-D ) 13.3,
J
) 8.7), -177.3
N1-D‚‚‚N9
13C NMR (CDCl3) δ 152.4 (C2, J ) 168.9, J C-N ) 3.9), 149.4
(N1′,1J N1′-N9 ) 10.3), -99.2 (N9).
1
4
1
3
1
1
(C8, J ) 156.0, J ) 3.3, J C-N ) 2.7), 130.3 (C6, J ) 161.1,
N-{[5-[(p-Tolu yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
1-yl]m eth ylen e}-1,2,4-tr ia zole-4 a m in e (5). A solution of 13
(0.087 g, 0.405 mmol) in EtOH (6.50 mL) was refluxed with
p-toluidine (0.052 g, 0.485 mmol) for 4 h 30 min. The solvent
was evaporated, and the crude was purified by column
chromatography with the following eluents: 5:1 AcOEt-
hexane, p-toluidine [Rf ) 0.41 (10:1 CHCl3-EtOH)]; AcOEt,
(5) [Rf ) 0.47 (10:1 CHCl3-EtOH)]; 10:1 CHCl3-EtOH, (13)
[Rf ) 0.26 (10:1 CHCl3-EtOH)]. Yield 0.095 g, 85%. mp 224.7
3J C-N ) 3.7), 126.9 (C7, J C-N ) 4.6, J C-N ) 6.8), 122.6 (C5,
2
3
1J ) 165.0), 121.9 (C4, 1J ) 165.6), 115.3 (C2′/C5′, 1J ) 185.7,
2
1J C-N ) 14.6, J C-N ) 2.0), 112.9 (C3), 107.1 (C3′/C4′, 1J )
171.7, J C-N ) 2.7), 48.2 (CH3, 1J )136.9), 41.0 (CH3, 1J )
2
140.8); 15N NMR (CDCl3) δ -272.7 (N1), -171.8 (N1′, J N9-N1′
1
1
) 11.7), -83.5 (N9, J N9-N1′ ) 11.7).
(4a -15N4): 1H NMR (CDCl3) δ 12.90 (br, H10), 8.10 (d, H2/
H8, 3J H2/H8-N1′ ) 4.8), 6.96 (d, H4/H6), 6.92 (m, H2′/H5′, 2J H-N
1
3
) 2.4), 6.48 (t, H5, 3J H5-H4/H6 ) 3.7), 6.22 (m, H3′/H4′, 3J H-N
)
°C (decompose); H NMR (CDCl3) δ 12.77 (d, H10, J H10-H2
)
)
1
5
6.6). 1H NMR (THF-d8) δ 13.51 (ttt, H10, J H10-N1/N9 ) 47.9,
14.0), 8.53 (s, H8), 8.50 (s, H2′/H5′), 8.04 (dd, H2, J H2-H6
4
3J H2/H8-H10 ) 5.2, 2J H10/N1′ ) 1.5), 8.29 (dd, H2/H8, 3J H2/H8-N1′
)
0.7), 7.23 (m, Hm and H6), 7.09 (m, Ho), 7.06 (dd, H4, J H4-H6
) 1.8), 6.51 (dd, H5, 3J H5-H6 ) 3.2, 3J H5-H4 ) 4.2), 2.37 (s, CH3);
13C NMR (CDCl3) δ 157.8 (C8, 1J ) 159.3, 3J ) 3.1), 144.2 (C2,
1J ) 165.5, 3J ) 1.9), 140.8 (C6, 1J ) 164.7), 138.4 (C2′/C5′, 1J
2
5.2), 7.02 (m, H2′/H5′, J H-N ) 2.4), 6.92 (d, H4/H6), 6.35 (t,
H5, 3J H5-H4/H6 ) 3.7), 6.12 (m, H3′/H4′, 3J H-N ) 6.6); 13C NMR
1
1
(CDCl3) δ 148.7 (C2/C8, J ) 164.5, J C-N ) 10.4), 135.2 (C4/
1
1
1
C6, J ) 164.5), 122.4 (C5, J ) 166.9), 117.9 (C3/C7), 117.9
) 212.1), 136.5 (Ci), 135.9 (Cp), 135.7 (C4, J ) 166.6), 130.7
1
1
1
1
2
2
(C2′/C5′, 1J ) 188.2, J C-N ) 14.7), 108.2 (C3′/C4′, J ) 171.8,
2J C-N ) 5.9); 15N NMR (CDCl3) δ -193.3 (N1/N9), -169.8 (N1′,
1J N1′-N9 ) 2.8). 15N NMR (THF-d8) δ -193.8 (N1/N9), -171.6
(N1′).
(Cm, J ) 159.8), 122.0 (C5, J )168.5, J ) J ) 3.0), 119.7
(C7), 117.3 (Co, 1J ) 158.2), 116.7 (C3), 20.9 (CH3, 1J ) 127.3);
15N NMR (CDCl3) δ -237.3 (N1), -167.6 (N1′), -121.7 (N9),
-64.6 (N3′/N4′). The N-D derivative present a deuterium
signal: 2H NMR (CDCl3 + D2O): δ ) 12.66 (D10). Elemental
analysis calcd for C16H15N5: C 69.29, H 5.45, N 25.25; found:
C 69.67, H 5.50, N 25.25.
(4c-15N4): 1H NMR (CDCl3) δ 8.65 (dd, H2, J H2-N1 ) 2.9,
2
3J H2-N1′ ) 6.8), 8.62 (dd, H8, 2J H8-N9 ) 3.0, 3J H8-N1′ ) 6.8), 7.17
(m, H2′′/H5′′), 7.14 (m, H2′/H5′), 7.06 (d, H6), 6.63 (d, H5,
3J H5-H6 ) 5.4), 6.29 (m, H3′′/H4′′), 6.28 (m, H3′/H4′), 3.67 (br
s, H4); 1H NMR (THF-d8) δ 8.94 (dd, H2, 2J H2-N1 ) 2.8, 3J H2-N1′
N-{[5-[(p-Nitr op h en yla m in o)m eth ylen e]-1,3-cyclop en -
ta d ien -1-yl]m eth ylen e}-1,2,4-tr ia zole-4-a m in e (6). A solu-
tion of 13 (0.064 g, 0.298 mmol) in EtOH (7.00 mL) was
refluxed with p-nitroaniline (0.050 g, 0.362 mmol) for 24 h.
The solvent was evaporated, and the crude was purified by
column chromatography with the following eluents: 50:1
CHCl3-EtOH, p-nitroaniline [Rf ) 0.56 (10:1 CHCl3-EtOH)];
20:1 CHCl3-EtOH, (6) [Rf ) 0.34 (10:1 CHCl3-EtOH)], 10:1
2
3
) 6.4), 8.93 (dd, H8, J H8-N9 ) 2.8, J H8-N1′′ ) 6.4), 7.25 (m,
H2′/H5′ or H2′′/H5′′), 7.22 (m, H2′/H5′ or H2′′/H5′′), 7.08 (d,
H6), 6.60 (d, H5, 3J H5-H6 ) 5.4), 6.18 (m, H3′/H4′ or H3′′/H4′′),
6.16 (m, H3′/H4′ or H3′′/H4′′), 3.65 (br s, H4); 13C NMR (CDCl3)
1
1
1
δ 141.0 (C2, J ) 159.5), 139.7 (C8, J ) 160.5), 135.9 (C5, J
1
3
) 169.3), 131.4 (C6, J ) 169.3, J C-N ) 10.4), 116.1 (C2′/C5′
1
1
or C2′′/C5′′, J ) 187.8, J C-N1′ ) 15.2), 116.0 (C2′/C5′ or C2′′/
CHCl3-EtOH, (13) [Rf ) 0.26 (10:1 CHCl3-EtOH)]. Yield
C5′′, J ) 187.5, J C-N1′ ) 15.2), 109.3 (C3′/C4′ or C3′′/C4′′, J
0.009 g, 10%. 1H NMR (CDCl3) δ 12.74 (d, H10, J H10-H2
)
1
1
1
3
2
1
) 171.8, J C-N ) 5.5), 109.0 (C3′/C4′ or C3′′/C4′′, J ) 171.8,
13.8), 8.56 (s, H8), 8.53 (s, H2′/H5′), 8.32 (m, Hm), 8.01(d, H2),
4
2J C-N ) 5.5), 42.3 (C4, 1J ) 124.3); 15N NMR (CDCl3) δ -172.5
7.35 (m, H6), 7.26 (m, Ho), 7.09 (dd, H4, J H4-H6 ) 1.6), 6.59
(N1′ and N1′′), -60.4 (N1, J N-N ) 11.3), -53.6 (N9, J N-N
)
(dd, H5, J H5-H6 ) 3.2, J H5-H4 ) 4.5). HRMS m/e (M+) calcd
for C15H12N6O2 308.10200, found 308.10303.
1
1
3
3
11.5).15N NMR (THF-d8) δ -173.7 (N1′′), -172.5 (N1′), -61.2
(N1), -52.2 (N9).
N-{[5-[(Dim eth ylam in o)m eth ylen e]-1,3-cyclopen tadien -
1-yl]m eth ylen e]-1,3-d im eth yl-1,2,4-tr ia zole-5-a m in e (16).
A solution of 11 (0.50 g, 1.61 mmol) in EtOH (10.0 mL) was
refluxed with 1,3-dimethyl-5-amino-1,2,4-triazole (0.216 g,
1.927 mmol) for 4 h. The solvent was evaporated, and the crude
was purified by column chromatography with the following
eluents: 1:9 EtOH-AcOEt, (16) [Rf ) 0.51 (10:1 CHCl3-
[
15N3]-N-{[5-[(P h en yla m in o)m et h ylen e]-1,3-cyclop en -
ta d ien -1-yl]m eth ylen e}p yr r ole-1-a m in e (3-15N3). A solu-
tion of 15-15N2 (0.098 g, 0.456 mmol) in EtOH (5.00 mL) was
refluxed with labeled aniline (0.054 g, 0.574 mmol) for 2 h 30
min. The solvent was evaporated, and the crude was purified
by column chromatography (1:20 AcOEt-hexane) to afford
3-15N3 (0.095 g, 79%). 1H NMR (CDCl3) δ 13.26 (ddd, H10,
1J H10-N1 ) 88.2, 3J H10-H2 ) 13.5, 1hJ H10‚‚‚N9) 4.0), 8.53 (dd, H8,
2J H8-N9 ) 2.8, 3J H8-N1′ ) 6.9), 7.97 (dd, H2, 5J H2-H6 ) 1.0), 7.43
1
EtOH)], yield 0.18 g, 46%. mp 181.3 °C; H NMR (CDCl3) δ
4
9.26 (s, H2), 9.12 (s, H8), 7.01 (dd, H6, J H6-H4 ) 1.6), 6.97
3
3
(dd, H4), 6.52 (dd, H5, J H5-H4 ) 4.5, J H5-H6 ) 3.2), 3.79 (s,
N-CH3 of triazole), 3.43 (s, CH3), 3.34 (s, CH3), 2.35 (s, C-CH3
of triazole); 13C NMR (CDCl3) δ 160.9 (C8, 1J ) 158.1, 3J )
2
(m, Hm), 7.25 (m, Ho), 7.19 (m, Hp), 7.13 (m, H2′/H5′, J H-N
3
4
) 0.8, J H-N ) 2.3), 7.09 (ddd, H6), 6.91 (ddd, H4, J H4-H6
)
5
3
3
2
1
1.9, J H4-H8 ) 0.6), 6.47 (dd, H5, J H5-H6 ) 3.0, J H5-H4 ) 4.4),
2.3), 158.7 (C5′, 3J ) 10.6), 158.0 (C3′, J ) 7.1), 153.0 (C2, J
6.30 (m, H3′/H4′, J H-N ) 6.1); 13C NMR (CDCl3) δ 149.6 (C8,
)169.4), 135.2 (C6, 1J ) 165.5), 129.0 (C7), 125.4 (C4, 1J )
165.6), 123.1 (C5, J ) 165.7, J ) J ) 3.4), 113.8 (C3), 47.9
(CH3, 1J ) 138.6), 40.5 (CH3, 1J ) 138.4), 33.1 (N-CH3 of
3
1J ) 158.8, J ) 3.7, J C-N ) 6.1), 142.8 (C2, J )166.6, J )
3
1
1
3
1
2
2
2.3, J C-N ) 15.6), 139.8 (Ci, J C-N ) 14.9), 137.5 (C6, 1J
1
1

Tautomerism of 6-Aminofulvene-1-aldimines
J . Org. Chem., Vol. 67, No. 5, 2002 1471
triazole, 1J ) 140.2), 14.1 (C-CH3 of triazole, 1J )127.9 Hz);
15N NMR (CDCl3) δ -268.2 (N1), -191.9 (N1′), -161.9 (N4′),
-132.9 (N9), -98.6 (N2′). Elemental analysis calcd for
13H17N5: C 64.17, H 7.04, N 28.78; found: C 64.28, H 7.35,
N 28.98.
N-{[5-[(P h en yla m in o)m eth ylen e]-1,3-cyclop en ta d ien -
chromated Cu KR radiation. As only thin plates were available
for the X-ray diffraction experiments the poor data quality
resulted in a low percentage of observed reflections and in high
values of R factors. A second set of data was recorded and that
with the large number of observed reflections were main-
tained: brown crystal of 0.60 × 0.33 × 0.07 mm cell param-
eters from least-squares fit of 37 reflections, 15.358(3), 9.991-
(1), 18.047(2) Å, orthorhombic, Pbcn, Z ) 8, R ) 0.096 for 1204
observed reflections. The structure was solved by direct
methods27 and refined by least-squares procedures on Fobs. All
hydrogen atoms were unambiguously obtained from difference
Fourier maps and were included isotropically in the last cycles
of refinement. Most of the calculations were carried out with
the XTAL.28The CIF file has been deposited with the Cam-
bridge Crystallographic Data Center 162335.
C
1-yl]m eth ylen e}-1,3-d im eth yl-1,2,4-tr ia zole-5-a m in e (7).
A solution of 16 (0.13 g, 0.53 mmol) in EtOH (8.00 mL) was
refluxed with aniline (0.06 mL, 0.66 mmol) for 1 h 15 min.
The solvent was evaporated, and the crude was purified by
column chromatography (1:4 AcOEt-CHCl3) to afford 7 [Rf )
0.75 (10:1 CHCl3-EtOH)] (0.119 g, 76%). mp 164.1 °C; 1H
3
NMR (CDCl3) δ 14.01 (d, H10, J H10-H2 ) 13.1), 9.07 (s, H8),
8.00 (d, H2), 7.45 (m, H6), 7.38 (m, Hm), 7.24 (m, Ho), 7.23
4
3
(m, Hp), 7.09 (dd, H4, J H4-H6 ) 1.5), 6.51 (dd, H5, J H5-H6
)
3J H5-H4 ) 3.7), 3.71 (s, N-CH3 of triazole), 2.37 (s, C-CH3 of
triazole); 13C NMR (CDCl3) δ 160.7 (C8, 1J ) 161.6), 158.8 (C5′),
158.1 (C3′), 146.4 (C2, 1J ) 167.8), 142.5 (C6, 1J ) 165.3), 139.9
(Ci), 136.1 (C4, 1J ) 168.5), 130.0 (Cm, 1J ) 163.4), 125.8 (Cp,
1J ) 163.6), 125.4 (C7), 122.5 (C5, 1J ) 168.3), 119.0 (Co, 1J )
159.2), 118.0 (C3), 33.9 (N-CH3 of triazole), 14.3 (C-CH3 of
Ack n ow led gm en t. We are indebted to DGES/MEC
(BQU-2000-0252 and BQU-2000-0868) of Spain for
financial support. S.H.A. also thanks ANPCyT (PICT
06-04330) and Fundacio´n Antorchas.
triazole); 15N NMR (CDCl3) δ -232.4 (N1, J N-H ) 86.4),
1
J O010625V
-194.7 (N1′), -156.3 (N4′), -150.3 (N9), -96.3 (N2′). Elemen-
tal analysis calcd for C17H17N5: C 70.08, H 5.88, N 24.04;
found: C 69.86, H 5.92, N 23.91. The corresponding N-D
derivative presents the following NMR spectra: 2H NMR
(CDCl3 + D2O): δ ) 13.82 (D10).
(27) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.;
Moliterni, A. G. G.; Burla, M. C.; Polidori, G.; Camalli, M.; Spagna, R.
SIR97, A package for Crystal Structure Solution by Direct Methods
and Refinement; University of Bari, Italy, 1997.
(28) Hall, S. R., du Boulay, D. J ., Olthof-Hazekamp, R., Eds. The
Xtal System of Crystallographic Software; ‘Xtal3. 6’ User’s Manual,
1999, The University of Western Australia, Australia.
X-r a y An a lysis. Crystal data for compound 3 were collected
using a Seifert XRD3000-S diffractometer with graphite mono-