Synthesis and iNOS/nNOS inhibitory activities of new benzoylpyrazoline derivatives

Article abstract of DOI:10.1016/j.tet.2004.03.013

A series of new Δ²-pyrazoline derivatives has been synthesized by means of a 1,3-dipolar-cycloaddition reaction. Ethyl 3-(5-methoxy-2-nitrobenzoyl)-Δ²-pyrazoline-5-carboxylate (5a) has been designed for the formation of the benzoylpy

Full text of DOI:10.1016/j.tet.2004.03.013

Tetrahedron 60 (2004) 4051–4069
Synthesis and iNOS/nNOS inhibitory activities of new
benzoylpyrazoline derivatives
a
a
b
b
b
´
´
´
´
*
M. Dora Carrion, M. Encarnacion Camacho, Josefa Leon, Germaine Escames, Vıctor Tapias,
b
Darıo Acuna-Castroviejo, Miguel A. Gallo and Antonio Espinosa
a
a
,
´
˜
a
´
´
´
Departamento de Quımica Farmaceutica y Organica, Facultad de Farmacia, c/Campus de Cartuja s/n, 18071 Granada, Spain
´
Departamento de Fisiologıa, Facultad de Medicina, c/Avenida de Madrid s/n, 18071 Granada, Spain
b
Received 19 December 2003; revised 12 February 2004; accepted 2 March 2004
Abstract—A series of new D2-pyrazoline derivatives has been synthesized by means of a 1,3-dipolar-cycloaddition reaction. Ethyl 3-(5-
methoxy-2-nitrobenzoyl)-D2-pyrazoline-5-carboxylate (5a) has been designed for the formation of the benzoylpyrazoline system present in
these derivatives. Two synthetic routes have been utilized changing the starting products in the cycloaddition reaction. In both routes, the
majority product obtained was only a D2-pyrazoline. The intermediate ethyl 1-acyl-3-(2-nitrobenzoyl-5-substituted)-D2-pyrazoline-5-
carboxylate derivatives have been transformed into the final compounds by means of several chemical treatments. The compounds have been
biologically evaluated as inhibitors of nitric oxide synthase (NOS), showing better affinity towards the inducible NOS isoform than versus
neuronal NOS.
q 2004 Elsevier Ltd. All rights reserved.
1. Introduction
disease.9 Up to now, the current research is orientated (a)
to establish the adequate inhibition level of NOS so that
its beneficial effects are kept, and (b) to identify more
selective inhibitor compounds of each NOS isoenzyme,
since the control of certain pathological states could be
achieved. Although many inhibitors of NOS are known,
very few of them show selectivity for only one iso-
form.10–12 The studies carried out until this moment
indicate that the goal of attaining selectivity for iNOS
over nNOS is more difficult than achieving selectivity for
iNOS over eNOS.13
Nitric oxide (NO) is a biologically active compound. The
synthesis of NO is catalyzed by a family of enzymes called
NO synthases (NOS). Three NOS isoforms have been well
identified and named according to the cell type or conditions
in which they were first described: endothelial NOS
(eNOS), neuronal NOS (nNOS) and inducible NOS
(iNOS).1 Each one of the isoforms converts L-arginine to
L-citrulline and nitric oxide utilizing NADPH and O2 as
cofactors, as well as the flavin-adenine dinucleotide (FAD),
the flavin mononucleotide (FMN), tetrahydrobiopterin,
heme and calcium-calmoduline.2 Nitric oxide has impor-
tant physiological functions including neurotransmission,
blood pressure homeostasis, platelet aggregation, and
immunological defense mechanisms.3 The magnitude
and duration of NO synthesis make its action physiological
or pathological. Thus, although NO participates in the
synaptic transmission in a normal way, the excessive levels
which are produced by nNOS can become neurotoxic,
and can be involved in different neurological disorders such
as Alzheimer’s disease,4 the amyotrophic lateral sclerosis5
or Hungtinton’s disease.6 On the other hand, the high
production of NO by the inducible isoform of the nitric
oxide synthase is related to disorders like the septic
shock,7 inflammatory arthritis,8 and inflammatory bowel
Melatonin (N-acetyl-5-methoxytryptamine) 1 is a hormone
that is synthesized and secreted into the general circulation
by the pineal gland.14 Inhibitory actions of melatonin in
the rat15,16 and human17 central nervous system (CNS) have
been reported. These inhibitory actions may be the cause of
the anticonvulsant, hypnotic, antitumoral, antioxidant and
neuroprotective properties.18 Diverse experiments, have
suggested that melatonin attenuates glutamate-mediated
responses in the rat striatum.19 The inhibitory effects of
melatonin in the striatum may be mediated through
inhibition of NOS, as has been reported in rat cerebellum
and hypothalamus.20–22 This inhibition is dose-dependent
and calmodulin-dependent.23
Recently, the D2-pyrazoline compounds have raised a great
interest because of their multiple pharmacological appli-
cations such as antibacterials, antifungicals, anticonvul-
sants,24 hypotensives,25 antidepressants,26 analgesics,
antiinflammatories27 and neuroprotectives.28 In this paper,
Keywords: Addition reactions; Pyrazolines; Benzisoxazoles; Anti-
inflammatory compounds.
*
Corresponding author. Tel.: þ34-958-243850; fax: þ34-958-243845;
e-mail address: aespinos@ugr.es
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.03.013

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4052
2. Results and discussion
2.1. Chemistry
Scheme 1 shows the synthetic pathway used. The method
employed for the formation of the ethyl 3-(2-nitro-5-
substitutedbenzoyl)-D2-pyrazoline-5-carboxylate deriva-
tives is a 1,3-dipolar cycloaddition reaction. For the
construction of the benzoylpyrazoline system by means of
the procedure before mentioned, two options are possible,
which seem to be of equal interest. The synthesis of
pyrazoline 5a has been taken as a model with the aim of
analyzing which is the most suitable route to prepare these
compounds. In the route A the 5-methoxy-2-nitrodiazo-
acetophenone 2a acting as a 1,3-dipole, reacts with an active
dipolarophile (ethyl acrylate) and in the route B, 5-methoxy-
2-nitrophenyl vinyl ketone 3a, acting as dipolarophile,
reacts with ethyl diazoacetate. Both routes lead to the same
intermediate ethyl 5-(5-methoxy-2-nitrobenzoyl)-D1-pyra-
zoline-3-carboxylate 4a which is not isolated, but it
tautomerizes quickly to the racemate ethyl 3-(5-methoxy-
2-nitrobenzoyl)-D2-pyrazoline-5-carboxylate 5a.
Figure 1.
taking as a prototype melatonin, we have carried out the
synthesis of a new series of D2-pyrazoline derivatives
(represented by the general formula A) with the aim of
searching for new selective inhibitors of NOS (Fig. 1).
The two synthetic routes which lead to the intermediate
5a are equally viable, and in both cases the yield of the
1,3-dipolar cycloaddition reaction was 80%. The choice of
the route B as the method of synthesis for the construction of
the benzoylpyrazolinic system was based on the easiness
with which the starting compounds 2a and 3a were
synthesized: for the preparation of the compound 5-meth-
oxy-2-nitrodiazoacetophenone 2a, 4 steps of synthesis with
a global yield 48% were needed, whereas for the preparation
of the compound 5-methoxy-2-nitrophenyl vinyl ketone 3a
only 3 steps of synthesis with a global yield 75% were
necessary (Scheme 2).
Once the second strategy was chosen as the synthetic
method, a modification of the conditions of reaction was
carried out, using a base (pyridine) and a polar solvent
(acetonitrile), so that the yield increased up to 90% in the
case of D2-pyrazoline 5a and the time of reaction
diminished (from 16 to 10 h). Accordingly, we took this
Scheme 1.
Scheme 2.

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4053
Scheme 3.
procedure as the general method for the preparation of the
benzoylpyrazolinic system in the different series a
(R1¼OCH3), b (R1¼Cl) and c (R1¼H). The use of pyridine
could allow the change of 1-pyrazoline to 2-pyrazoline since
its basic character facilitates the prototropy. Once the
benzoylpyrazoline derivatives 5a,b,c have been synthe-
sized, they have been transformed into the corresponding
acyl derivatives 11a,b,c–19a,b,c by treating them with
triethylamine and acetic anhydride or the corresponding
acyl chloride. Twenty-seven intermediates are obtained,
nine of each series, where the radical R2 can be a lineal
chain in the case of Me, Et, Pr and Bu, or a cyclic chain, in
the case of c-C3H5, c-C4H7, c-C5H9, c-C6H11 and Ph. The
yields are similar in the three series and ranges between 92
and 100%. These acyl derivatives underwent diverse
chemical treatments to perform the right modifications in
the aromatic and pyrazolinic rings, with the aim of getting
the different final compounds (Scheme 3).
ring of the 27 acyl derivatives leads to compounds 20a,b,c–
28a,b,c. In series a, the reduction is accomplished by
catalytic hydrogenation with Pd/C and the yield oscillates
between 80 and 84%. In series b, the reduction was carried
out with Fe and FeSO4 in water, in order to avoid
dechlorination, in this series the yield oscillates between
95 and 97%. In series c, the reduction was carried out whith
Fe/FeSO4 due to the better yield obtained with this method
(95–96%).
The compounds 29 and 30 were obtained starting from the
acyl derivatives 11a and 13a by treating them with SnCl2 in
ethanol with quantitative yield. The formation of these
derivatives is justified by the attack of the hydroxyl group of
the intermediate hydroxyamino reduction to the carbonyl
group, the benzo[c]isoxazole ring being formed by posterior
loss of a water molecule. Compounds 31–33 are formed by
catalytic hydrogenation with Pd/C starting from the
corresponding nitroarene (12a, 15a and 19a). Both, the
quantity of catalyst and the time of reaction were higher
The reduction of the nitro group belonging to the aromatic

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4054
The nNOS activity was measured monitoring the conversion
of L-[3H]-arginine into L-[3H]-citrulline, according to the
method described by Bredt and coll.32 For the measurement
of the iNOS activity, the induction of the enzyme was
achieved by means of the intravenous injection of
lipopolysaccharide (LPS).
In general, the majority of compounds show better values of
inhibition towards the iNOS isoform than towards the nNOS
isoform. Next, a comparative analysis of the cerebral
iNOS/striatal nNOS activities is carried out.
Among the benzoylpyrazoline derivatives 20a,b,c–28a,b,c,
compounds 28b and 28c with a phenyl group in R2 showed
higher affinity against iNOS than for nNOS. In 29 and 30
derivatives, there are not significant values of inhibition of
both isoforms, and, accordingly, the elimination of the
amino group in position 2 of the aromatic ring by formation
of the benzo[c]isoxazole does not lead to positive results
with regard to the NOS inhibition. This corroborates
previous results obtained by our Group, which demonstrate
the need of a hydrogen bond donor group in this position
(an amino or amino monosubstituted group), for the
formation of a hydrogen bond with the biologic target
which is important for the NOS inhibitory activity.12
Scheme 4.
than the ones used for the reduction of the aromatic nitro
group, in this case the yield ranged between 19 and 43%.
The derivatives 34 and 35 were obtained by hydrolysis
starting from their esters 20a and 27a with Na2CO3, and
posterior neutralization with Amberlite IR-120 [H]þ resin,
with 40–41% yield (Scheme 4).
2.2. Striatal nNOS and cerebral iNOS inhibitory activity
The effect of the final compounds on nNOS activity has
been studied in striatum and rat brain (Table 1), with the
object of evaluating its possible inhibition and selectivity
versus the two isoforms of the nitric oxide synthase. The
concentration of the compounds essayed has been 1 mM.
Compounds in which the rigidity has been diminished by
reduction of the pyrazoline ring (compounds 31 and 32) or
Table 1.
Compounds
Series
R1
R2
Me
% nNOS inhibition
% iNOS inhibition
20
a
b
c
a
b
c
a
b
c
a
b
c
a
b
c
a
b
c
a
b
c
a
b
c
a
b
c
a
a
a
a
a
a
a
OCH3
Cl
H
OCH3
Cl
21.74^4.20
2.37^3.68
—
15.15^3.61
3.90^5.29
5.41^2.75
11.49^4.08
3.71^3.53
—
11.34^1.75
4.57^3.21
1.11^0.55
4.94^2.38
4.71^1.33
5.49^0.34
5.24^1.20
—
7.07^1.67
30.38^2.77
—
21
22
23
24
25
26
27
28
Et
24.03^6.91
25.39^1.61
13.25^4.36
14.63^2.26
20.34^3.78
26.42^2.71
12.98^5.27
8.86^7.39
0.14^3.46
8.25^5.25
22.33^2.25
14.50^6.48
19.96^8.45
4.43^9.62
14.13^4.04
3.53^5.92
20.15^2.72
23.28^3.14
11.08^5.73
4.94^1.37
25.47^1.23
3.77^4.43
35.62^3.23
32.44^0.52
—
H
OCH3
Cl
Pr
H
OCH3
Cl
Bu
H
OCH3
Cl
c-C3H5
c-C4H7
c-C5H9
c-C6H11
Ph
H
OCH3
Cl
H
—
OCH3
Cl
11.59^0.57
—
—
19.79^3.56
—
3.99^4.50
5.73^2.29
—
—
—
—
—
—
—
—
—
H
OCH3
Cl
H
OCH3
Cl
H
29
30
31
32
33
34
35
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
Me
Pr
Et
c-C3H5
Ph
Me
—
23.93^4.21
22.05 ^ 4.19
37.58^1.90
22.66^6.07
36.34^2.99
c-C6H11
Values of inhibition striatal nNOS and cerebral iNOS. Each value is the mean of three experiments performed by triplicate in striatum (nNOS) and brain
(iNOS) homogenates of rats.

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4055
by reduction of the carbonyl group (compound 33), only
present iNOS inhibition. Moreover, they present more
significant inhibition values regarding the more similar rigid
compounds 21a, 24a and 28a. Again, the 33 derivative with
a phenyl group in R2 presents the highest value of iNOS
inhibition.
spectroscopy (HRMS) was carried out on a VG AutoSpec Q
high-resolution mass spectrometer (Fison Instrument).
Elemental analyses were performed on a Perkin–Elmer
240 C and agreed with theoretical values within ^0.4%.
Flash-chromatography was carried out using silica gel 60,
230–240 mesh (Merck), and the solvent mixture reported
within parentheses was used as eluent. Evaporations were
carried out in vacuo with a rotary evaporator.
The 34 and 35 acids obtained by hydrolysis of the ester
function present affinity toward the iNOS isoform. The
reduction of the size of the substituent leads to better
inhibition values regarding their analogues 20a and 27a.
4.1.1. Starting materials
4.1.1.1. Synthesis of 5-methoxy-2-nitrodiazoaceto-
phenone 2a. A 0.54 M solution of CH2N2 was added
dropwise with stirring under argon at 210 8C to a solution
of 5-methoxy-2-nitrobenzoyl chloride30 (2 g, 9.27 mmol) in
dry diethyl ether (10 mL). The reaction mixture was stirred
for 3 h. Evaporation of the solvent rendered a residue that
was purified by flash chromatography (ethyl acetate/hexane
1:2) to give 2: 1.2 g (65% yield);0 thick oil. 1H NMR
The comparative analysis between iNOS/nNOS activities
shows that the compounds present better selectivity by the
iNOS isoform versus nNOS. The inhibitory potency iNOS is
improved with structures which present a decrease of the
conformational rigidity or an acid group in position 5.
0
0
The results obtained with these compounds prompted us the
attainment of selective inhibitors of an only NOS isoform,
what could mean the control of certain pathologies. Besides,
they would help us to know the structure and action
mechanism of each isoform.
(400 MHz, CDCl3) d 8.08 (d, 1H, H-3 , J3 –4 ¼9.0 Hz); 6.98
(dd, 1H, H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.8 Hz); 6.89 (d, 1H,
0
0
0
0
H-60, J6 –4 ¼2.8 Hz); 5.4 (s, 1H, –CH–N2); 3.9 (s, 3H,
–OCH3).13C NMR (100 MHz, CDCl3) d 184.43 (C-1);
165.14 (C-50); 140.45 (C-20); 127.36 (C-30, C-10); 115.30
(C-40); 113.44 (C-60); 56.32 (C-2, –OCH3). HR LSIMS
calcd for C9H7N3O4Na (MþNa)þ 244.0334, found:
244.0333.
0
0
3. Conclusions
4.1.1.2. Synthesis of 2-nitrophenyl-5-substituted vinyl
ketone 3a,b,c. 5-Methoxy-2-nitrobenzaldehyde 7a (synthe-
sized from 5-hydroxy-2-nitrobenzaldehide 6 with MeI and
K2CO3 in THF),29 commercial 5-chloro-2-nitrobenzalde-
hyde 7b and commercial 2-nitrobenzaldehyde 7c, were
transformed into the corresponding allylic alcohols 10a,b,c
by quantitative addition of vinylmagnesium bromide.31
Oxidation with CrO3 leads to the 2-nitrophenyl-5-substi-
tuted vinylketone 3a,b,c.31
The synthesis and biologic evaluation of a new class of
D2-pyrazoline derivatives have been carried out. The
benzoylpyrazoline moiety has been made by means of the
1,3-dipolar cycloaddition reaction using different starting
compounds which lead to an only type of D2-pyrazoline
(5a). The compounds presented in this report show more
affinity towards iNOS isoform, the values of inhibition
produced by 28b, 33 and 35 derivatives are remarkable. For
the inhibition of the NOS activity, the presence of a free
amino group in position 2 of the aromatic ring is important,
since 29 and 30 compounds with a benzoisozaxole ring do
not inhibit the nNOS and iNOS isoforms. This corroborates
previous results obtained by our research group, where a
hydrogen bond donor group in this position is needed.
4.1.1.3. General procedures for the preparation of
compounds 5a,b,c. Procedure 1. Ethyl acrylate (0.04 mL,
0.39 mmol) was slowly added to stirred 5-methoxy-2-
nitrodiazoacetophenone 2 (0.085 g, 0.39 mmol) at 65 8C.
The reaction mixture was stirred for 16 h, CH2Cl2 was
added, and washed with H2O (2£20 mL). The organic phase
was dried (Na2SO4), filtered, and evaporated. The residue
was recrystallized from CH2Cl2/hexane.
4. Experimental
4.1. Chemistry
Procedure 2. Ethyl diazoacetate (0.16 mL, 1.38 mmol) was
slowly added to stirred 5-methoxy-2-nitrophenyl vinyl
ketone 3a (0.285 g, 1.38 mmol) at 65 8C. The reaction
mixture was stirred for 16 h, CH2Cl2 was added, and washed
with H2O (2£20 mL). The organic phase was dried
(Na2SO4), filtered and evaporated. The residue was
recrystallized from CH2Cl2/hexane.
Reactions were performed under an inert atmosphere of
argon. Solvents were dried according to standard methods.
Melting points (mp) were taken in open capillaries on a
Electrothermal melting point apparatus and are uncorrected.
Nuclear magnetic resonance (NMR) spectra were recorded
on a 400.1 MHz 1H and 100.3 MHz 13C NMR Bruker
1
ARX-400 or 300.13 MHz H and 75.58 MHz 13C NMR
Procedure 3. Pyridine (0.013 mL, 0.172 mmol) was added
to a solution of the corresponding 5-methoxy-2-nitrophenyl
vinyl ketone 3a,b,c (1.38 mmol) in 4 mL of dry acetonitrile.
Ethyl diazoacetate was slowly added (0.16 mL, 1.38 mmol)
to the stirred solution. The reaction mixture was stirred
for 10 h and washed with 5% HCl (2£10 mL). The
organic phase was dried (Na2SO4), filtered and
evaporated to dryness. The residue was recrystallized from
CH2Cl2/hexane.
Bruker AMX-300 spectrometers, and chemical shifts (ppm)
are reported relative to the solvent peak (CHCl3 in CDCl3 at
d 7.24 and 77.1 ppm; CH3OH in CD3OD at 3.34 and
49.9 ppm). Signal are designated as follows: s, singlet; bs,
broad singlet; d, doublet; dd, doublet of doublet; ddd, double
doublet of doublet; t, triplet; pt, pseudotriplet; dt, double
of triplet; tt, triplet of triplet; q, quadruplet; pc, pseudo-
quadruplet; pq, pseudoquintuplet; m, multiplet. Coupling
constants (J) are expressed in hertz. High-resolution mass

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4056
4.1.1.3.1. Ethyl 3-(5-methoxy-2-nitrobenzoyl)-D2-pyra-
excess molar) and acetic anhydride or the corresponding
acyl chloride (a molar equivalent) was added to a solution of
the corresponding pyrazoline 5a, 5b or 5c (0.85 mmol) in
dry CH2Cl2 (10 mL) at room temperature. The reaction
mixture was stirred for 3 h, filtered and washed with H2O,
10% HCl, 2 M NaOH, H2O and brine. The organic phase
was dried (Na2SO4), and filtered. Evaporation of the solvent
rendered a residue that was purified by flash chroma-
tography (ethyl acetate–hexane 1:4).
zoline-5-carboxylate 5a. Compound 5a was obtained as a
yellow solid (98.7 mg, 80% yield), as described in pro-
cedure 1. Compound 5a was obtained as a yellow solid
(98.7 mg, 80% yield), as described in the procedure 2.
Compound 5a was obtained as a yellow solid (111 mg, 90%
yield) starting from 3a,31 as described in procedure 3; mp
1
144–146 8C. H NMR (300 MHz, CDCl3) d 8.20 (d, 1H,
0
0
H-30, J3 –4 ¼9.1 Hz); 7.00 (dd, 1H, H-4 , J4 –3 ¼9.1 Hz,
0
0
0
0
0
0
0
0
J4 –6 ¼2.9 Hz); 6.87 (d, 1H, H-6 , J6 –4 ¼2.9 Hz); 6.74 (bs,
1H, –NH); 4.49 (dd, 1H, H-5, J5,4b¼12.7 Hz, J5,4a
5.6 Hz); 4.22 (c, 2H, –COOCH2–CH3, J¼7.1 Hz); 3.89
¼
4.1.1.4.1. Ethyl 1-acetyl-3-(5-methoxy-2-nitrobenzoyl)-
D2-pyrazoline-5-carboxylate 11a. White solid; yield 100%;
1
(s, 3H, –OCH3); 3.45 (H-4 a, J4a–4b¼17.5 Hz, J4a–5
¼
mp 102–104 8C. H NMR (300 MHz, CDCl3) d 8.11 (d,
0
0
0
1H, H-30, J3 –4 ¼9.1 Hz); 7.06 (dd, 1H, H-4 , J4 –3 ¼9.1 Hz,
0
0
0
5.6 Hz); 3.29 (1H, H-4b, J4b–4a¼17.5 Hz, J4b,5¼12.7 Hz);
1.29 (t, 3H, –COO–CH2–CH3 J¼7.1 Hz).13C NMR
(75 MHz, CDCl3) d187.41 (Ph–CO–); 171.27 (–COO–
CH2–CH3); 163.95 (C-50); 150.07 (C-3); 140.29 (C-20);
137.85 (C-10); 126.59 (C-30); 115.52 (C-40); 113.58 (C-60);
62.30 (–COO–CH2–CH3); 61.85 (C-5); 56.25 (–OCH3);
33.44 (C-4); 14.17 (–COO–CH2–CH3). HR LSIMS calcd
for C14H15N3O6Na (MþNa)þ 344.0858, found 344.0867.
0
0
0
0
J4 –6 ¼2.7 Hz); 6.92 (d, 1H, H-6 , J6 –4 ¼2.7 Hz); 4.94
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.93 (s, 3H, –OCH3); 3.52
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.28
(dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.11
(s, 3H, –CO–CH3); 1.27 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz). 13C NMR (75 MHz, CDCl3) d 187.06 (Ph–CO–);
169.84, 168.97 (–COOCH2CH3, –N–CO–); 164.05 (C-50);
152.51 (C-3); 140.75 (C-20); 136.33 (C-10); 126.57 (C-30);
116.06 (C-40); 114. 09 (C-60); 62.33 (–COOCH2CH3);
59.89 (C-5); 56.36 (–OCH3); 35.65 (C-4); 21.07 (–CO–
CH3); 14.04 (–COOCH2CH3). HR LSIMS calcd for
C16H18N3O7 (Mþþ1) 364.1144, found 364.1144.
4.1.1.3.2. Ethyl 3-(5-chloro-2-nitrobenzoyl)-D2-pyrazo-
line-5-carboxylate 5b. Compound 5b was obtained as a
yellow solid (382 mg, 85% yield) starting from 3b,31 as
described in procedure 3; mp 143–146 8C. 1H NMR
(300 MHz, CDCl3) d 8.05 (d, 1H, H-30, J3 –4 ¼8.7 Hz);
0
0
7.55 (dd, 1H, H-40, J4 –3 ¼8.7 Hz, J4 –6 ¼2.3 Hz); 7.44 (d,
0
0
0
0
1H, H-60, J6 –4 ¼2.3 Hz); 6.82 (bs, 1H, –NH); 4.52 (dd, 1H,
H-5, J5–4b¼12.8 Hz, J5–4a¼5.7 Hz); 4.23 (c, 2H, –COO–
CH2–CH3, J¼7.1 Hz) 3.43 (dd, 1H, H-4a, J4a–4b¼17.6 Hz,
J4a–5¼5.7 Hz); 3.28 (dd, 1H, H-4b, J4b–4a¼17.6 Hz,
J4b–5¼12.8 Hz); 1.30 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz). 13C NMR (75 MHz, CDCl3): d 185.72 (Ph–CO–),
171.04 (–COO–CH2–CH3); 149.49 (C-3);0 145.81
(C-200); 140.73 (C-50); 136.68 (C-10); 130.65 (C-4 ); 129.27
(C-6 ); 125.53 (C-30); 62.39 (–COO–CH2–CH3); 61.97
(C-5); 35.17 (C-4); 14.17 (–COO–CH2–CH3). HR LSIMS
calcd for C13H12ClN3O5Na (MþNa)þ 348.0363, found
348.0361.
4.1.1.4.2. Ethyl 3-(5-methoxy-2-nitrobenzoyl)-1-propionyl-
D2-pyrazoline-5-carboxylate 12a. White solid; yield 98%;
mp 116–118 8C. 1H NMR (300 MHz, CDCl3) d 8.13 (d, 1H,
0
0
0
H-30, J3 –4 ¼9.1 Hz); 7.07 (dd, 1H, H-4 , J4 –3 ¼9.1 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.8 Hz); 6.93 (d, 1H, H-6 , J6 –4 ¼2.8 Hz); 4.94
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.93 (s, 3H, –OCH3); 3.51
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.27 (dd,
1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.42 (m, 2H,
–CO–CH2–CH3); 1.28 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz); 1.04 (t, 3H, –CO–CH2–CH3 J¼7.5 Hz). 13C NMR
(75 MHz, CDCl3) d 187.12 (Ph–CO–); 173.31 (–N–
CO–); 169.10 (–COO–CH2–CH3); 164.07 (C-50); 152.34
(C-3); 140.77 (C-20);0 136.47 (C-10); 126.59 (C-30); 116.08
(C-40); 114. 06 (C-6 ); 62.18 (–COO–CH2–CH3); 59.04
(C-5); 56.36 (–OCH3); 35.39 (C-4); 26.85 (–CO–CH2–
CH3); 14.06 (–COO–CH2–CH3); 8.37 (–CO–CH2–CH3).
HR LSIMS calcd for C17H19N3O7Na (MþNa)þ 400.1120,
found 400.1120.
4.1.1.3.3. Ethyl 3-(2-nitrobenzoyl)-D2-pyrazoline-5-
carboxylate 5c. Compound 5c was obtained as a yellow
solid (353 mg, 88% yield) starting from 3c,31 as described in
procedure 3; mp 107–109 8C. 1H NMR (300 MHz, CDCl3)
0
d 8.09 (d, 1H, H-30, J3 –4 ¼8.1 Hz); 7.71 (dt, 1H, H-5 ,
0
0
0
0
0
0
0
0
0
J5 –4 ¼J5 –6 ¼7.5 Hz, J5 –3 ¼1.1 Hz); 7.60 (dt, 1H, H-4 ,
0
0
0
0
0
0
J4 –3 ¼8.1 Hz, J4 –5 ¼7.5 Hz, J4 –6 ¼1.5 Hz); 7.49 (dd, 1H,
H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.5 Hz); 6.75 (bs, 1H, –NH);
4.50 (dd, 1H, H-5, J5–4b¼12.6 Hz, J5–4a¼5.6 Hz); 4.22
(c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.45 (dd, 1H, H-4a,
J4a–4b¼17.6 Hz, J4a–5¼5.6 Hz); 3.29 (dd, 1H, H-4b,
J4b–4a¼17.6 Hz, J4b–5¼12.6 Hz); 1.29 (t, 3H, –COO–
CH2–CH3 J¼7.1 Hz). 13C NMR (75 MHz, CDCl3): d
187.38 (Ph–CO–); 171.20 (–COO–CH2–CH3); 150.00
(C-3)0 ; 147.67 (C-200); 135.15 (C-100); 133.90 (C-50); 130.78
(C-4 ); 129.17 (C-6 ); 124.03 (C-3 ); 62.30 (–COO–CH2–
CH3); 61.87 (C-5); 33.37 (C-4); 14.15 (–COO–CH2–CH3).
HR LSIMS calcd for C13H13N3O5Na (MþNa)þ 314.0752,
found 314.0753.
4.1.1.4.3. Ethyl 1-butyryl-3-(5-methoxy-2-nitrobenzoyl)-
D2-pyrazoline-5-carboxylate 13a. White solid; yield 98%;
mp 106–108 8C. 1H NMR (300 MHz, CDCl3) d 8.14 (d, 1H,
0
0
0
0
0
H-30, J3 –4 ¼9.1 Hz); 7.07 (dd, 1H, H-4 , J4 –3 ¼9.1 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.8 Hz); 6.93 (d, 1H, H-6 , J6 –4 ¼2.8 Hz); 4.95
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (C, 2H,
–COOCH2CH3, J¼7.1 Hz); 3.94 (s, 3H, –OCH3); 3.51 (dd,
1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.27 (dd, 1H,
H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.39 (m, 2H, –CO–
CH2–CH2–CH3); 1.55 (m, 2H, –CO–CH2–CH2–CH3);
1.28 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz); 0.84 (t, 3H,
–CO–CH2–CH2–CH3, J¼7.5 Hz). 13C NMR (75 MHz,
CDCl3) d 187.16 (Ph–CO–); 172.61 (–N–CO–); 169.09
(–COO–CH2–CH3); 164.08 (C-50); 152.34 (C-3); 140.77
(C-20); 136.50 (C-10); 126.58 (C-30); 116.11 (C-40); 114. 06
4.1.1.4. General procedure for the preparation of
compounds 11a,b,c–19a,b,c. Triethylamine (a small

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4057
(C-60); 62.21 (–COO–CH2–CH3); 59.01 (C-5); 56.36
(–OCH3); 35.42, 35.26 (–CO–CH2–CH2–CH3, C-4);
18.03 (–CO–CH2–CH2–CH3); 14.07 (–COO–CH2–CH3);
13.68 (–CO–CH2–CH2–CH3). HR LSIMS calcd for
C18H21N3O7Na (MþNa)þ 414.1277, found 414.1272.
CH2–CH3); 164.09 (C-50); 152.36 (C-3); 140.67 (C-20);
136.67 (C-10); 126.56 (C-30); 116.11 (C-40); 113.94 (C-60);
62.19 (–COO–CH2–CH3); 59.11 (C-5); 56.38 (–OCH3);
37.36 (C-1cyclobut.); 35.19 (C-4); 24.58, 24.30 (C-2,
C-4cyclobut.); 18.15 (C-3cyclobut.); 14.08 (–COO–CH2–
CH3). HR LSIMS calcd for C19H21N3O7Na (MþNa)þ
426.1277, found: 426.1281.
4.1.1.4.4. Ethyl 3-(5-methoxy-2-nitrobenzoyl)-1-penta-
noyl-D2-pyrazoline-5-carboxylate 14a. White solid; yield
96%; mp 73–75 8C; 1H NMR (300 MHz, CDCl3) d 8.13 (d,
4.1.1.4.7. Ethyl 1-cyclopentanecarbonyl-3-(5-methoxy-
2-nitrobenzoyl)-D2-pyrazoline-5-carboxylate 17a. White
0
0
1H, H-30, J3 –4 ¼9.1 Hz); 7.07 (dd, 1H, H-4 , J4 –3 ¼9.1 Hz,
0
0
0
0
0
1
0
0
0
J4 –6 ¼2.8 Hz); 6.93 (d, 1H, H-6 , J6 –4 ¼2.8 Hz); 4.94
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (C, 2H,
–COOCH2CH3, J¼7.1 Hz); 3.93 (s, 3H, –OCH3); 3.51 (dd,
1H, H-4a, J4a–4b¼18.6 Hz, J4a–5¼12.9 Hz); 3.26 (dd, 1H,
H-4b, J4b–4a¼18.6 Hz, J4b–5¼6.2 Hz); 2.40 (m, 2H, –CO–
CH2–CH2–CH2–CH3); 1.48 (m, 2H, –CO–CH2–CH2–
CH2–CH3); 1.27 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz);
1.23 (m, 2H, –CO–CH2–CH2–CH2–CH3); 0.80 (t, 3H,
solid; yield 98%; mp 1290–131 8C. H NMR (300 MHz,
0
0
CDCl3) d 8.14 (d, 1H, H-3 , J3 –4 ¼9.1 Hz); 7.07 (dd, 1H,
H-40, J4 –3 ¼9.1 Hz, J4 –6 ¼2.8 Hz); 6.93 (d, 1H, H-6 ,
0
0
0
0
0
0
0
J6 –4 ¼2.8 Hz); 4.94 (dd, 1H, H-5, J5–4a¼12.9 Hz,
J5–4b¼6.2 Hz); 4.21 (m, 2H, –COOCH2CH3); 3.93 (s,
3H, –OCH3); 3.50 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.9 Hz); 3.26 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.2 Hz); 3.06 (m, 1H, H-1cyclopent.); 1.65–1.40 (m, 8H, H-2,
H-3, H-4, H-5cyclopent.); (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz).13C NMR (75 MHz, CDCl3) d 187.26 (Ph–CO–);
175.69 (–N–CO–); 169.14 (–COO–CH2–CH3); 164.09
(C-500); 152.18 (C-3); 140.71 (C-200); 136.67 (C-10); 126.58
(C-3 ); 116.12 (C-40); 113.96 (C-6 ); 62.14 (–COO–CH2–
CH3); 59.18 (C-5); 56.37 (–OCH3); 41.89 (C-1cyclopent.);
35.24 (C-4); 29.59, 29.20 (C-2, C-5cyclopent.); 26.24, 26.12
(C-3, C-4cyclopent.); 14.06 (–COO–CH2–CH3). HR LSIMS
calcd for C20H23N3O7Na (MþNa)þ 440.1433, found:
440.1437.
–CO–CH2–CH2–CH2–CH3,
J¼7.3 Hz).13C
NMR
(75 MHz, CDCl3) d 187.13 (Ph–CO–); 172.79 (–N–
CO–); 169.05 (–COO–CH2–CH3); 164.08 (C-50); 152.33
(C-3); 140.77 (C-20);0 136.54 (C-10); 126.55 (C-30); 116.06
(C-40); 114. 03 (C-6 ); 62.19 (–COO–CH2–CH3); 59.03
(C-5); 56.37 (–OCH3); 35.42 (C-4); 33.19 (–CO–CH2–
CH2–CH2–CH3); 26.66 (–CO–CH2–CH2–CH2–CH3);
22.40 (–CO–CH2–CH2–CH2–CH3); 14.06 (–COO–
CH2–CH3); 13.64 (–CO–CH2–CH2–CH2–CH3). HR
LSIMS calcd for C19H23N3O7Na (MþNa)þ 428.1433,
found 428.1434.
4.1.1.4.8. Ethyl 1-cyclohexanecarbonyl-3-(5-methoxy-2-
nitrobenzoyl)-D2-pyrazoline-5-carboxylate 18a. White
4.1.1.4.5. Ethyl 1-cyclopropanecarbonyl-3-(5-methoxy-
2-nitrobenzoyl)-D2-pyrazoline-5-carboxylate 15a. White
1
solid; yield 98%; mp 1160–118 8C; H NMR (300 MHz,
1
0
0
solid; yield 99%; mp 1370–139 8C. H NMR (300 MHz,
CDCl3) d 8.14 (d, 1H, H-3 , J3 –4 ¼9.1 Hz); 7.07 (dd, 1H,
0
0
0
0
0
0
0
CDCl3) d 8.13 (d, 1H, H-3 , J3 –4 ¼9.1 Hz); 7.06 (dd, 1H,
H-40, J4 –3 ¼9.1 Hz, J4 –6 ¼2.8 Hz); 6.93 (d, 1H, H-6 ,
H-40, J4 –3 ¼9.1 Hz, J4 –6 ¼2.8 Hz); 6.94 (d, 1H, H-6 ,
J6 –4 ¼2.8 Hz); 4.92 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼
0
0
0
0
0
0
0
0
0
J6 –4 ¼2.8 Hz); 4.94 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b
¼
6.0 Hz); 4.19 (m, 2H, –COOCH2CH3); 3.93 (s, 3H,
6.4 Hz); 4.21 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.93
(s, 3H, –OCH3); 3.53 (dd, 1H, H-4a, J4a–4b¼18.6 Hz,
J4a–5¼12.9 Hz); 3.29 (dd, 1H, H-4b, J4b–4a¼18.6 Hz,
J4b–5¼6.4 Hz); 2.12 (m, 1H, H-1cycloprop.); 1.26 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 1.06–0.98, 0.85–0.78 (2m,
4H, H-2, H-3cycloprop.).13C NMR (75 MHz, CDCl3) d 187.29
(Ph–CO–); 173.12 (–N–CO–); 169.11 (–COO–CH2–
CH3); 164.09 (C-50); 152.57 (C-3); 140.61 (C-20); 136.63
(C-10); 126.65 (C-30); 116.09 (C-40); 114. 01 (C-60); 62.14
(–COO–CH2–CH3); 59.34 (C-5); 56.38 (–OCH3); 35.37
(C-4); 14.08 (–COO–CH2–CH3); 11.45 (C-1cycloprop.);
9.44, 9.39 (C-2, C-3cycloprop.). HR LSIMS calcd
C18H19N3O7Na (MþNa)þ 412.1120, found: 412.1122.
–OCH3); 3.49 (dd, 1H, H-4a, J4a–4b¼18.6 Hz, J4a–5
12.9 Hz); 3.24 (dd, 1H, H-4b, J4b–4a¼18.6 Hz, J4b–5
¼
¼
6.0 Hz); 2.65 (tt, 1H, H-1cyclohex., Jtransdiaxial¼11.5 Hz,
Jcis¼3.2 Hz); 1.75–1.56 (m, 5H, Hec. cyclohex.); 1.26 (t,
3H, –COO–CH2–CH3, J¼7.1 Hz); 1.40–1.05 (m, 5H,
Hax. cyclohex.).13C NMR (75 MHz, CDCl3) d 187.11 (Ph–
CO–); 175.41 (–N–CO–); 169.05 (–COO–CH2–CH3);
164.08 (C-50); 152.06 (C-3); 140.88 (C-20); 136.58 (C-10);
126.43 (C-30); 116.09 (C-40); 114.06 (C-60); 62.13 (–COO–
CH2–CH3); 59.10 (C-5); 56.36 (–OCH3); 41.55
(C-1cyclohex.); 35.18 (C-4); 28.49, 28.45 (C-2, C-6cyclohex.);
25.80, 25.54, 25.50 (C-3, C-4, C-5cyclohex.); 14.06 (–COO–
CH2–CH3). HR LSIMS calcd for C21H25N3O7Na (MþNa)þ
454.1590, found 454.1583.
4.1.1.4.6. Ethyl 1-cyclobutanecarbonyl-3-(5-methoxy-2-
nitrobenzoyl)-D2-pyrazoline-5-carboxylate 16a. White
4.1.1.4.9. Ethyl 1-benzoyl-3-(5-methoxy-2-nitrobenzoyl)-
D2-pyrazoline-5-carboxylate 19a. White solid; yield
94%; mp 134–136 8C. 1H NMR (300 MHz, CDCl3) d
1
solid; yield 99%; mp 1370–139 8C. H NMR (300 MHz,
0
0
CDCl3) d 8.15 (d, 1H, H-3 , J3 –4 ¼9.1 Hz); 7.08 (dd, 1H,
H-40, J4 –3 ¼9.1 Hz, J4 –6 ¼2.8 Hz); 6.91 (d, 1H, H-6 ,
8.12 (d, 1H, H-30, J3 –4 ¼9.1 Hz); 7.60 (dd, 2H, H-2,
H-6benz., J2-3benz.¼7.1 Hz, J2-4benz.¼1.3 Hz); 7.40 (tt, 1H,
H-4benz., J4-3benz.¼7.4 Hz, J4-2benz.¼1.3 Hz); 7.26 (pt, 2H,
0
0
0
0
0
0
0
0
0
J6 –4 ¼2.8 Hz); 4.93 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b
¼
6.1 Hz); 4.22 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.94
(s, 3H, –OCH3); 3.48 (dd, 1H, H-4a, J4a–4b¼18.6 Hz,
J4a–5¼12.9 Hz); 3.39 (m, 1-H, H-1cyclobut.); 3.24 (dd, 1H,
H-4b, J4b–4a¼18.6 Hz, J4b–5¼6.1 Hz); 2.25–2.15, 1.98–
1.72 (2m, 6H, H-2, H-3, H-4cyclobut.); 1.28 (t, 3H, –COO–
CH2–CH3, J¼7.1 Hz). 13C NMR (75 MHz, CDCl3) d
187.18 (Ph–CO–); 174.11 (–N–CO–); 169.09 (–COO–
H-3, H-5benz., J3-4benz.¼7.4 Hz, J3-2benz.¼7.1 Hz); 7.01 (dd,
0
1H, H-40, J4 –3 ¼9.1 Hz, J4 –6 ¼2.8 Hz); 6.87 (d, 1H, H-6 ,
0
0
0
0
0
0
J6 –4 ¼2.8 Hz); 5.17 (dd, 1H, H-5, J5–4a¼12.7 Hz, J5–4b
¼
6.1 Hz); 4.26 (c, 2H, –COOCH2CH3, J¼7.1 Hz); 3.89
(s, 3H, –OCH3); 3.57 (dd, 1H, H-4a, J4a–4b¼18.7 Hz,
J4a–5¼12.7 Hz); 3.31 (dd, 1H, H-4b, J4b–4a¼18.7 Hz,

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4058
J4b–5¼6.1 Hz); 1.30 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz).13C NMR (75 MHz, CDCl3) d 187.18 (Ph–CO–);
168.96, 167.32 (–COO–CH2–CH3, –N–CO–); 164.20
(C-50); 153.30 (C-3); 140.49 (C-20); 136.64 (C-10); 132.04
(C-1benz.); 131.89 (C-4benz.); 129.97 (C-2, C-6benz.); 127.72
(C-3, C-5benz.); 126.52 (C-30); 116.12 (C-40); 113.95 (C-60);
62.92 (–COO–CH2–CH3); 60.36 (C-5); 56.34 (–OCH3);
34.90 (C-4); 14.13 (–COO–CH2–CH3). HR LSIMS calcd
for C21H19N3O7Na (MþNa)þ 448.1120, found: 448.1118.
CH2–CH3); 151.92 (C-3); 146.28 (C-20); 141.04 (C-50);
135.24 (C-10); 131.48 (C-40); 129.60 (C-60); 125.44 (C-30);
62.28 (–COO–CH2–CH3); 59.18 (C-5); 35.21 (–CO–
CH2–CH2–CH3, C-4); 17.98 (–CO–CH2–CH2–CH3);
14.07 (–COO–CH2–CH3); 13.68 (–CO–CH2–CH2–
CH3). HR LSIMS: calcd for C17H18ClN3O6Na (MþNa)þ
418.0781, found 418.0783.
4.1.1.4.13. Ethyl 3-(5-chloro-2-nitrobenzoyl)-1-penta-
noyl-D2-pyrazoline-5-carboxylate 14b. White solid; yield
95%; mp 97–99 8C; 1H NMR (300 MHz, CDCl3) d 8.08 (d,
4.1.1.4.10. Ethyl 1-acetyl-3-(5-chloro-2-nitrobenzoyl)-
D2-pyrazoline-5-carboxylate 11b. White solid; yield 94%;
mp 134–136 8C. 1H NMR (300 MHz, CDCl3) d 8.07 (d, 1H,
0
1H, H-30, J3 –4 ¼8.7 Hz); 7.63 (dd, 1H, H-4 , J4 –3 ¼ 8.7 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.3 Hz); 7.51 (d, 1H, H-6 , J6 –4 ¼2.3 Hz); 4.96 (dd,
1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.21 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.49 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.25 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.42 (m, 2H, –CO–
CH2–CH2–CH2–CH3); 1.51 (m, 2H, –CO–CH2–CH2–
CH2–CH3); 1.27 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz);
1.25 (m, 2H, –CO–CH2–CH2–CH2–CH3) 0.82 (t, 3H,
0
H-30, J3 –4 ¼8.7 Hz); 7.63 (dd, 1H, H-4 , J4 –3 ¼8.7 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.3 Hz); 7.51 (d, 1H, H-6 , J6 –4 ¼2.3 Hz); 4.96
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.22 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.51 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.26 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.12 (s, 3H, –CO–CH3);
1.28 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz). 13C NMR
(75 MHz, CDCl3) d 185.52 (Ph–CO–); 169.82, 168.79
(–COO–CH2–CH3, –N–CO–); 152.10 (C-3); 146.33
(C-200); 141.04 (C-50); 135.11 (C-10); 131.52 (C-40); 129.61
(C-6 ); 125.45 (C-30); 62.33 (–COO–CH2–CH3); 59.11
(C-5); 35.48 (C-4); 21.08 (–CO–CH3); 14.06 (–COO–
CH2–CH3). HR LSIMS calcd for C15H14ClN3O6Na
(MþNa)þ 390.0468, found 390.0462.
–CO–CH2–CH2–CH2–CH3,
J¼7.3 Hz).13C
NMR
(75 MHz, CDCl3) d 185.60 (Ph–CO–); 172.76 (–N–
CO–); 168.88 (–COO–CH2–CH3); 151.94 (C-3); 146.26
(C-200); 141.05 (C-50); 135.30 (C-10); 131.44 (C-40); 129.58
(C-6 ); 125.44 (C-30); 62.28 (–COO–CH2–CH3); 59.19
(C-5); 35.23 (C-4); 33.14 (–CO–CH2–CH2–CH2–CH3);
26.60 (–CO–CH2–CH2–CH2–CH3); 22.25 (–CO–CH2–
CH2–CH2–CH3); 14.06 (–COO–CH2–CH3); 13.65
(–CO–CH2–CH2–CH2–CH3).HR LSIMS calcd for
C18H21ClN3O6 (Mþþ1) 410.1118, found 410.1118.
4.1.1.4.11. Ethyl 3-(5-chloro-2-nitrobenzoyl)-1-propionyl-
D2-pyrazoline-5-carboxylate 12b. White solid; yield 98%;
1
mp 87–90 8C. H NMR (300 MHz, CDCl3) d 8.08 (d, 1H,
0
0
H-30, J3 –4 ¼8.7 Hz); 7.63 (dd, 1H, H-4 , J4 –3 ¼ 8.7 Hz,
4.1.1.4.14. Ethyl 3-(5-chloro-2-nitrobenzoyl)-1-cyclo-
propanecarbonyl-D2-pyrazoline-5-carboxylate 15b. White
0
0
0
0
0
0
0
0
J4 –6 ¼2.3 Hz); 7.51 (d, 1H, H-6 , J6 –4 ¼2.3 Hz); 4.95 (dd,
1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.49 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.25 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.44 (m, 2H, –CO–
CH2–CH3); 1.27 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz),
1.05 (t, 3H, –CO–CH2–CH3, J¼7.5 Hz).13C NMR
(75 MHz, CDCl3) d 185.58 (Ph–CO–); 173.28 (–N–
CO–); 168.91 (–COO–CH2–CH3); 151.92 (C-3); 146.27
(C-200); 141.03 (C-50); 135.21 (C-10); 131.51 (C-40); 129.58
(C-6 ); 125.45 (C-30); 62.28 (–COO–CH2–CH3); 59.20
(C-5); 35.19 (C-4); 26.83 (–CO–CH2–CH3); 14.06
(–COO–CH2–CH3); 8.34 (–CO–CH2–CH3). HR LSIMS
calcd for C16H16ClN3O6Na (MþNa)þ 404.0625, found
404.0630.
1
solid; yield 98%; mp 1290–131 8C; H NMR (300 MHz,
0
0
CDCl3) d 8.07 (d, 1H, H-3 , J3 –4 ¼8.7 Hz); 7.61 (dd, 1H,
H-40, J4 –3 ¼8.7 Hz, J4 –6 ¼2.3 Hz); 7.52 (d, 1H, H-6 ,
0
0
0
0
0
0
0
J6 –4 ¼2.3 Hz); 4.95 (dd, 1H, H-5, J5–4a¼12.9 Hz,
J5–4b¼6.1 Hz); 4.20 (m, 2H, –COO–CH2–CH3); 3.51
(dd, 1H, H-4a, J4a–4b¼18.6 Hz, J4a–5¼12.9 Hz); 3.27 (dd,
1H, H-4b, J4b–4a¼18.6 Hz, J4b–5¼6.3 Hz); 2.10 (m, 1H,
H-1cycloprop.); 1.26 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz);
1.02, 0.83 (2m, 4H, H-2, H-3cycloprop.)
13C NMR (75 MHz,
CDCl3) d 185.73 (Ph–CO–); 173.11 (–N–CO–); 168.90
(–COO–CH2–CH3); 152.13 (C-3); 0 146.12 (C-200);
141.04 (C-50); 135.35 (C-10); 131.40 (C-4 ); 129.59 (C-6 );
125.56 (C-30); 62.21 (–COO–CH2–CH3); 59.51 (C-5);
35.16
(C-4);
14.10
(–COO–CH2–CH3);
11.50
(C-1cycloprop.); 9.54, 9.47 (C-2, C-3cycloprop.). HR LSIMS
calcd for C17H16ClN3O6Na (MþNa)þ 416.0625, found:
416.0621.
4.1.1.4.12. Ethyl 1-butyryl-3-(5-chloro-2-nitrobenzoyl)-
D2-pyrazoline-5-carboxylate 13b. White solid; yield 98%;
1
mp 82–84 8C; H NMR (400 MHz, CDCl03) d 8.10 (d, 1H,
H-30, J3 –4 ¼8.7 Hz); 7.64 (dd, 1H, H-4 , J4 –3 ¼8.7 Hz,
4.1.1.4.15. Ethyl 3-(5-chloro-2-nitrobenzoyl)-1-cyclo-
butanecarbonyl-D2-pyrazoline-5-carboxylate 16b. White
solid; yield 98%; mp 970–99 8C; 1H NMR (300 MHz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼ 2.1 Hz); 7.52 (d, 1H, H-6 , J6 –4 ¼2.1 Hz); 4.97 (dd,
1H, H-5, J5–4a¼13.0 Hz, J5–4b¼6.1 Hz); 4.22 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.50 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼13.0 Hz); 3.26 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.46 (1 pq, –CO–CH2–
CH2–CH3, Ha, Jgem¼15.3 Hz, JHa–CH2¼7.4 Hz); 2.37 (1
0
0
CDCl3) d 8.11 (d, 1H, H-3 , J3 –4 ¼8.7 Hz); 7.64 (dd, 1H,
H-40, J4 –3 ¼8.7 Hz, J4 –6 ¼2.3 Hz); 7.50 (d, 1H, H-6 ,
0
0
0
0
0
0
0
J6 –4 ¼2.3 Hz); 4.95 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b
¼
6.1 Hz); 4.22 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.47
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.41 (m,
1H, H-1cyclobut.); 3.23 (dd, 1H, H-4b, J4b–4a¼18.7 Hz,
J4b–5¼6.1 Hz); 2.25–2.15, 1.98–1.72 (2m, 6H, H-2, H-3,
H-4cyclobut.); 1.28 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz).
13C NMR (75 MHz, CDCl3) d 185.64 (Ph–CO–); 174.10
pq, –CO–CH2–CH2–CH3, Hb, Jgem¼15.3 Hz, JHb–CH
¼
2
7.4 Hz); 1.57 (m, 2H, –CO–CH2–CH2–CH3); 1.29 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 0.87 (t, 3H, –CO–CH2–
CH2–CH3, J¼7.4 Hz).13C NMR (100 MHz, CDCl3) d
185.60 (Ph–CO–); 172.56 (–N–CO–); 168.89 (–COO–

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4059
(–N–CO–); 168.90 (–COO–CH2–CH3); 152.00 (C-3);
146.12 (C-200); 141.07 (C-50); 135.44 (C-10); 131.42 (C-40);
129.55 (C-6 ); 125.45 (C-30); 62.27 (–COO–CH2–CH3);
59.28 (C-5); 37.32 (C-1cyclobut.); 35.01 (C-4); 24.71, 24.22
(C-2, C-4cyclobut.); 18.18 (C-3cyclobut.); 14.08 (–COO–
CH2–CH3). HR LSIMS calcd for C18H18ClN3O6Na
(MþNa)þ 430.0783, found: 430.0781.
C-6benz.); 129.42 (C-60); 127.72 (C-3, C-5benz.); 125.37
(C-30); 62.30 (–COO–CH2–CH3); 60.40 (C-5); 34.69
(C-4); 14.05 (–COO–CH2–CH3). HR LSIMS calcd for
C20H16ClN3O6Na (MþNa)þ 452.0625, found 452.0623.
4.1.1.4.19. Ethyl 1-acetyl-3-(2-nitrobenzoyl)-D2-pyrazo-
line-5-carboxylate 11c. White solid; yield 99%; mp 112–
0
1
114 8C. H NMR (300 MHz, CDCl3) d 8.12 (d, 1H, H-3 ,
0
0
0
0
0
0
0
4.1.1.4.16. Ethyl 3-(5-chloro-2-nitrobenzoyl)-1-cyclo-
pentanecarbonyl-D2-pyrazoline-5-carboxylate 17b. White
solid; yield 97%; mp 740–76 8C; 1H NMR (300 MHz,
J3 –4 ¼8.1 Hz); 7.78 (t, 1H, H-5 , J5 –6 ¼J5 –4 ¼7.5 Hz);
7.69 (dt, 1H, H-40, J4 –3 ¼8.1 Hz, J4 –5 ¼7.5 Hz, J4 –6
¼
0
0
0
0
0
0
1.1 Hz); 7.57 (dd, 1H, H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.1 Hz);
4.96 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.23 (c,
2H, –COO–CH2–CH3, J¼7.1 Hz); 3.53 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.29 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.12 (s, 3H, –CO–CH3);
1.29 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz). 13C NMR
(75 MHz, CDCl3) d 187.06 (Ph–CO–); 169.88, 168.92
(–COO–CH2–CH3, –N–CO–); 152.44 (C-3); 148.26
(C-200); 134.15 (C-50); 133.67 (C-10); 131.66 (C-40); 129.59
(C-6 ); 123.95 (C-30); 62.27 (–COO–CH2–CH3); 58.99
(C-5); 35.62 (C-4); 21.05 (–CO–CH3); 14.06 (–COO–
CH2–CH3). HR LSIMS calcd for C15H15N3O6Na (MþNa)þ
356.0858, found 356.0858.
0
0
0
0
0
0
CDCl3) d 8.09 (d, 1H, H-3 , J3 –4 ¼8.7 Hz); 7.63 (dd, 1H,
H-40, J4 –3 ¼8.7 Hz, J4 –6 ¼2.3 Hz); 7.51 (d, 1H, H-6 ,
0
0
0
0
0
0
0
J6 –4 ¼2.3 Hz); 4.96 (dd, 1H, H-5, J5–4a¼12.9 Hz,
J5–4b¼6.1 Hz); 4.21 (m, 2H, –COO–CH2–CH3); 3.49
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.24 (dd,
1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 3.06 (m, 1H,
H-1cyclopent.); 1.81–1.42 (m, 8H, H-2, H-3, H-4, H-
5cyclopent.); 1.27 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz).13C
NMR (75 MHz, CDCl3) d 185.69 (Ph–CO–); 175.68 (–N–
CO–); 168.93 (–COO–CH2–CH3); 151.80 (C-3); 146.15
(C-200); 141.04 (C-50); 135.41 (C-10); 131.42 (C-40); 129.57
(C-6 ); 125.46 (C-30); 62.21 (–COO–CH2–CH3); 59.33
(C-5); 41.85 (C-1cyclopent.); 35.05 (C-4); 29.71, 29.20 (C-2,
C-5cyclopent.); 26.24, 26.11 (C-3, C-4cyclopent.); 14.06
(–COO–CH2–CH3). HR LSIMS calcd for C19H20ClN3O6-
Na (MþNa)þ 444.0938, found 444.0940.
4.1.1.4.20. Ethyl 3-(2-nitrobenzoyl)-1-propionyl-D2-
pyrazoline-5-carboxylate 12c. White solid; yield 98%; mp
106–108 8C. 1H NMR (300 MHz, CDCl3) d 8.11 (d, 1H, H-30,
0
0
0
0
0
0
0
J3 –4 ¼8.1 Hz); 7.77 (dt, 1H, H-5 , J5 –6 ¼J5 –4 ¼7.5 Hz,
J5 –3 ¼1.2 Hz); 7.68 (dt, 1H, H-40, J4 –3 ¼8.1 Hz,
0
0
0
00
4.1.1.4.17. Ethyl 3-(5-chloro-2-nitrobenzoyl)-1-cyclo-
hexanecarbonyl-D2-pyrazoline-5-carboxylate 18b. White
0
0
0
0
0
0
J4 –5 ¼7.5 Hz, J4 –6 ¼1.6 Hz); 7.55 (dd, 1H, H-6 , J6 –5
¼
1
0
0
syrup; yield 98%; H NMR (300 MHz, CDCl3) d 8.09 (d,
0
7.5 Hz, J6 –4 ¼1.6 Hz); 4.95 (dd, 1H, H-5, J5–4a¼12.9 Hz,
J5–4b¼6.2 Hz); 4.21 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz);
3.50 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.26
(dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.43 (m,
2H, –CO–CH2–CH3); 1.27 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz); 1.04 (t, 3H, –CO–CH2–CH3, J¼7.5 Hz).13C
NMR (75 MHz, CDCl3) d 187.13 (Ph–CO–); 173.33 (–N–
CO–); 169.04 (–COO–CH2–CH3); 152.27 (C-3); 148.19
(C-20); 134.15 (C-50); 133.79 (C-10); 131.60 (C-40);
129.56 (C-60); 123.97 (C-30); 62.20 (–COO–CH2–CH3);
59.11 (C-5); 35.34 (C-4); 26.81 (–CO–CH2–CH3); 14.06
(–COO–CH2–CH3); 8.35 (–CO–CH2–CH3). HR LSIMS
calcd for C16H17N3O6Na (MþNa)þ 370.1015, found
370.1014.
0
1H, H-30, J3 –4 ¼8.7 Hz); 7.63 (dd, 1H, H-4 , J4 –3 ¼8.7 Hz,
0
0
0
0
0
0
0
0
J4 –6 ¼ 2.3 Hz); 7.51 (d, 1H, H-6 , J6 –4 ¼2.3 Hz); 4.94 (dd,
1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.0 Hz); 4.20 (m, 2H,
–COO–CH2–CH3); 3.47 (dd, 1H, H-4a, J4a–4b¼18.7 Hz,
J4a–5¼ 12.9 Hz); 3.23 (dd, 1H, H-4b, J4b–4a¼18.7 Hz,
J4b–5¼6.0 Hz); 2.66 (tt, H-1cyclohex., Jtransdiaxial¼11.5 Hz,
Jcis¼3.3 Hz); 1.72–1.04 (m, 10H, H-2, H-3, H-4, H-5,
H-6cyclohex.); 1.26 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz).
13C NMR (75 MHz, CDCl3) d 185.54 (Ph–CO–); 175.39
(–N–CO–); 168.84 (–COO–CH2–CH3); 151.67 (C-3);
146.27 (C-200); 140.97 (C-50); 135.28 (C-10); 131.39 (C-40);
129.64 (C-6 ); 125.31 (C-30); 62.19 (–COO–CH2–CH3);
59.21 (C-5); 41.51 (C-1cyclohex.); 34.97 (C-4); 28.56, 28.40
(C-2, C-6cyclohex.); 25.53, 25.45, 25.38 (C-3, C-4,
C-5cyclohex.); 14.03 (–COO–CH2–CH3). HR LSIMS calcd
for C20H22ClN3O6Na (MþNa)þ 458.1094, found 458.1097.
4.1.1.4.21. Ethyl 1-butyryl-3-(2-nitrobenzoyl)-D2-pyra-
zoline-5-carboxylate 13c. White syrup; yield 98%; 1H NMR
(400 MHz, CDCl3) d 8.11 (d, 1H, H-30, J3 –4 ¼ 8.1 Hz);
0
0
0
7.76 (t, 1H, H-50, J5 –6 ¼J5 –4 ¼7.5 Hz); 7.67 (dt, 1H, H-4 ,
0
0
0
0
4.1.1.4.18. Ethyl 1-benzoyl-3-(5-chloro-2-nitrobenzoyl)-
D2-pyrazoline-5-carboxylate 19b. White syrup; yield 98%.
0
0
0
0
0
0
J4 –3 ¼8.1 Hz, J4 –5 ¼7.5 Hz, J4 –6 ¼1.2 Hz); 7.54 (dd, 1H,
0
1H NMR (300 MHz, CDCl3) d 8.03 (d, 1H, H-3 , J3 –4
¼
H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.2 Hz); 4.95 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.20 (c, 2H, –COO–CH2–
CH3, J¼7.1 Hz); 3.49 (dd, 1H, H-4a, J4a–4b¼18.7 Hz,
J4a–5¼12.9 Hz); 3.25 (dd, 1H, H-4b, J4b–4a¼18.7 Hz,
J4b–5¼6.1 Hz); 2.42 (pq, 1H, –CO–CH2–CH2–CH3, Ha,
Jgem¼15.0 Hz, JHa–CH2¼7.4 Hz); 2.34 (pq, 1H, –CO–
CH2–CH2–CH3, Hb, Jgem¼15.0 Hz, JHb–CH2¼7.4 Hz);
1.54 (m, 2H, –CO–CH2–CH2–CH3); 1.26 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 0.83 (t, 3H, –CO–CH2–
CH2–CH3, J¼7.4 Hz).13C NMR (100 MHz, CDCl3) d
187.10 (Ph–CO–); 172.53 (–N–CO–);0 168.94 (–COO–
CH2–CH3); 152.23 (C-3); 148.07 (C-2 ); 134.12 (C-50);
133.73 (C-10); 131.56 (C-40); 129.47 (C-60); 123.89 (C-30);
0
0
0
0
0
0
8.7 Hz); 7.56 (m, 3H, H-40, H-2, H-6benz.); 7.45 (d, 1H, H-60,
0
0
J6 –4 ¼2.2 Hz); 7.41 (tt, 1H, H-4benz.
J4–2¼1.2 Hz); 7.27 (pt, 2H, H-3, H-5benz., J3-2benz.¼7.4 Hz,
¼6.8 Hz); 5.18 (dd, 1H, H-5, J5–4a¼12.8 Hz,
,
J4–3¼6.8 Hz,
J
3-4benz.
J5–4b¼6.2 Hz); 4.25 (c, 2H, –COO–CH2–CH3, J¼
7.1 Hz); 3.56 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.8 Hz); 3.31 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.2 Hz); 1.29 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz).13C
NMR (75 MHz, CDCl3) d185.62 (Ph–CO–); 168.75,
167.39 (–COO–CH2–CH3, –N–CO–); 152.87 (C-3);
146.15 (C-20); 141.06 (C-50); 135.35 (C-10); 133.20
(C-1benz.); 131.94 (C-4benz.); 131.26 (C-40); 129.76 (C-2,

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4060
62.12 (–COO–CH2–CH3); 59.01 (C-5); 35.29, 35.13
(–CO–CH2–CH2–CH3, C-4); 17.91 (–CO–CH2–CH2–
CH3); 13.99, 13.58 (–COO–CH2–CH3, –CO–CH2–CH2–
CH3). HR LSIMS calcd for C18H21N3O6Na (MþNa)þ
398.1328, found 398.1325.
H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.27–2.13, 1.98–
1.73 (2m, 6H, H-2, H-3, H-4cyclobut.); 1.27 (t, 3H, –COO–
CH2–CH3, J¼7.1 Hz).13C NMR (75 MHz, CDCl3) d
187.23 (Ph–CO–); 174.11 (–N–CO–);0 169.01 (–COO–
CH2–CH3); 152.35 (C-3); 147.94 (C-2 ); 134.20 (C-50);
134.00 (C-10); 131.53 (C-40); 129.43 (C-60); 123.95
(C-30); 62.18 (–COO–CH2–CH3); 59.16 (C-5); 37.31
(C-1cyclobut.); 35.13 (C-4); 24.68, 24.18 (C-2, C-4cyclobut.);
18.13 (C-3cyclobut.); 14.05 (–COO–CH2–CH3). HR LSIMS
calcd for C18H19N3O6Na (MþNa)þ 396.1171, found
396.1169.
4.1.1.4.22. Ethyl 3-(2-nitrobenzoyl)-1-pentanoyl-D2-pyr-
azoline-5-carboxylate 14c. White syrup; yield 96%; 1H
NMR (400 MHz, CDCl3) d 8.09 (d, 1H, H-30, J3 –4
¼
0
0
8.1 Hz); 7.74 (dt, 1H, H-50, J5 –6 ¼J5 –4 ¼7.5 Hz, J5 –3
¼
0
0
0
0
0
0
0.7 Hz); 7.65 (dt, 1H, H-40, J4 –3 ¼8.1 Hz, J4 –5 ¼7.5 Hz,
0
0
0
00
0
0
0
0
0
0
J4 –6 ¼1.3 Hz); 7.52 (dd, 1H, H-6 , J6 –5 ¼7.5 Hz, J6 –4
¼
1.1 Hz); 4.92 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.1 Hz);
4.17 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.48 (dd, 1H,
H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.23 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.42 (pq, 1H, –CO–CH2–
CH2–CH2–CH3, Ha, Jgem¼15.1 Hz, JHa–CH2¼ 7.6 Hz);
2.33 (pq, 1H, –CO–CH2–CH2–CH2–CH3, Hb, Jgem¼15.1
Hz, JHb–CH2¼7.6 Hz); 1.45 (m, 2H, –CO–CH2–CH2–
CH2–CH3); 1.23 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz);
1.17 (m, 2H, –CO–CH2–CH2–CH2–CH3) 0.75 (t, 3H,
–CO–CH2–CH2–CH2–CH3, J¼7.3 Hz). 13C NMR
(100 MHz, CDCl3) d187.03 (Ph–CO–); 172.66 (–N–
CO–); 168.86(–COO–CH2–CH3); 152.21 (C-3); 147.98
(C-200); 134.08 (C-50); 133.68 (C-10); 131.49 (C-40); 129.38
(C-6 ); 123.82 (C-30); 62.03 (–COO–CH2–CH3); 58.97
(C-5); 35.23 (C-4); 32.98 (–CO–CH2–CH2–CH2–CH3);
26.46 (–CO–CH2–CH2–CH2–CH3); 22.07 (–CO–CH2–
CH2–CCH2–CH3); 13.90, 13.48 (–COO–CH2–CH3,
–CO–CH2–CH2–CH2–CH3). HR LSIMS calcd for
C18H21N3O6Na (MþNa)þ 398.1328, found 398.13253.
4.1.1.4.25. Ethyl 1-cyclopentanecarbonyl-3-(2-nitro-
benzoyl)-D2-pyrazoline-5-carboxylate 17c. White syrup;
1
yield 97%. H NMR (300 MHz, CDCl3) d 8.11 (dd, 1H,
0
0
H-30, J3 –4 ¼8.1 Hz, J3 –5 ¼1.1 Hz); 7.77 (dt, 1H, H-5 ,
0
0
0
0
0
0
0
0
0
0
J5 –6 ¼J5 –4 ¼7.5 Hz, J5 –3 ¼1.1 Hz); 7.67 (dt, 1H, H-4 ,
0
0
0
0
0
0
J4 –3 ¼8.1 Hz, J4 –5 ¼7.5 Hz, J4 –6 ¼1.6 Hz); 7.54 (dd, 1H,
H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.6 Hz); 4.94 (dd, 1H, H-5,
0
0
0
0
J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.20 (m, 2H, –COO–
CH2–CH3); 3.49 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.9 Hz); 3.25 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.1 Hz); 3.06 (m, 1H, H-1cyclopent.); 1.91–1.06 (m, 8H, H-2,
H-3, H-4, H-5cyclopent); 1.26 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz). 13C NMR (75 MHz, CDCl3) d 187.29 (Ph–CO–);
175.70 (–N–CO–); 169.05 (–COO–CH2–CH3); 152.17
(C-3); 147.96 (C-200); 134.18 (C-500); 133.99 (C-10); 131.53
(C-40); 129.45 (C-6 ); 123.97 (C-3 ); 62.12 (–COO–CH2–
CH3); 59.22 (C-5); 41.84 (C-1cyclopent.); 35.18 (C-4); 29.66,
29.14 (C-2, C-5cyclopent.); 26.20, 26.07 (C-3, C-4cyclopent.),
14.03 (–COO–CH2–CH3). HR LSIMS calcd for
C19H21N3O6Na (MþNa)þ 410.1328, found 410.1326.
4.1.1.4.23. Ethyl 1-cyclopropanecarbonyl-3-(2-nitro-
benzoyl)-D2-pyrazoline-5-carboxylate 15c. White solid;
4.1.1.4.26. Ethyl 1-cyclohexanecarbonyl-3-(2-nitro-
benzoyl)-D2-pyrazoline-5-carboxylate 18c. White syrup;
1
yield 98%; mp 116–118 8C; H NMR (300 MHz, CDCl3)
d 8.11 (dd, 1H, H-30, J3 –4 ¼8.1 Hz, J3 –5 ¼1.2 Hz); 7.77
1
0
0
0
0
yield 98%; H NMR (300 MHz, CDCl3) d 8.13 (dd, 1H,
0
(dt, 1H, H-50, J5 –6 ¼J5 –4 ¼7.5 Hz, J5 –3 ¼1.2 Hz); 7.67
H-30, J3 –4 ¼8.1 Hz, J3 –5 ¼1.1 Hz); 7.77 (dt, 1H, H-5 ,
0
0
0
0
0
0
0
0
0
0
(dt, 1H, H-40, J4 –3 ¼8.1 Hz, J4 –5 ¼7.5 Hz, J4 –6 ¼1.6 Hz);
J5 –4 ¼7.6 Hz, J5 –6 ¼7.5 Hz, J5 –3 ¼1.1 Hz); 7.68 (dt, 1H,
0
0
0
0
0
0
0
0
0
0
0
0
7.57 (dd, 1H, H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.6 Hz); 4.95
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.3 Hz); 4.21 (m, 2H,
–COO–CH2–CH3); 3.52 (dd, 1H, H-4a, J4a–4b¼18.6 Hz,
J4a–5¼12.9 Hz); 3.28 (dd, 1H, H-4b, J4b–4a¼18.6 Hz,
J4b–5¼6.3 Hz); 2.11 (m, 1H, H-1cycloprop.); 1.26 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 1.01–0.98, 0.84–0.79 (2m,
4H, H-2, H-3cycloprop.). 13C NMR (75 MHz, CDCl3) d
187.27 (Ph–CO–); 173.14 (–N–CO–);0 169.03 (–COO–
CH2–CH3); 152.47 (C-3); 148.09 (C-2 ); 134.14 (C-50);
133.91 (C-10); 131.52 (C-40); 129.61 (C-60); 124.03 (C-30);
62.15 (–COO–CH2–CH3); 59.41 (C-5); 35.32 (C-4); 14.07
(–COO–CH2–CH3); 11.44 (C-1cycloprop.); 9.39, 9.35 (C-2,
C-3cycloprop.). HR LSIMS calcd for C17H17N3O6Na
(MþNa)þ 382.1015, found 382.1014.
H-40, J4 –3 ¼8.1 Hz, J4 –5 ¼7.6 Hz, J4 –6 ¼1.6 Hz); 7.54
0
0
0
0
0
0
0
0
0
0
(dd, 1H, H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.6 Hz); 4.92 (dd, 1H,
0
0
0
0
H-5, J5–4a¼12.9 Hz, J5–4b¼6.0 Hz); 4.19 (m, 2H, –COO–
CH2–CH3); 3.48 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.9 Hz); 3.24 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.0 Hz); 2.65 (tt, H-1cyclohex., Jtransdiaxial¼11.5 Hz, Jcis¼3.2
Hz); 1.72–1.04 (m, 10H, H-2, H-3, H-4, H-5, H-6cyclohex.);
1.25 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz). 13C NMR
(75 MHz, CDCl3) d 187.17 (Ph–CO–); 175.43 (–N–CO–);
168.97 (–COO–CH2–CH3); 152.07 (C-3); 148.10 (C-20);
134.17 (C-50); 133.91 (C-10); 131.53 (C-40); 129.52 (C-60);
123.83 (C-30); 62.13 (–COO–CH2–CH3); 59.12 (C-5);
41.50 (C-1cyclohex.); 35.12 (C-4); 28.54, 28.38 (C-2,
C-6cyclohex.); 25.77, 25.53, 25.46 (C-3, C-4, C-5cyclohex.),
14.03 (–COO–CH2–CH3). HR LSIMS calcd for
C20H23N3O6Na (MþNa)þ 424.1484, found 424.1485.
4.1.1.4.24. Ethyl 1-cyclobutanecarbonyl-3-(2-nitro-
benzoyl)-D2-pyrazoline-5-carboxylate 16c. White syrup;
1
yield 99%. H NMR (300 MHz, CDCl3) d 8.14 (dd, 1H,
0
4.1.1.4.27. Ethyl 1-benzoyl-3-(2-nitrobenzoyl)-D2-pyra-
zoline-5-carboxylate 19c. White solid; yield 92%; mp 135–
0
H-30, J3 –4 ¼8.0 Hz, J3 –5 ¼1.1 Hz); 7.77 (dt, 1H, H-5 ,
0
0
0
0
0
1
0
0
0
0
0
0
J5 –6 ¼ J5 –4 ¼7.5 Hz, J5 –3 ¼1.1 Hz); 7.68 (dt, 1H, H-4 ,
137 8C. H NMR (300 MHz, CDCl3) d 8.10 (dd, 1H, H-3 ,
0
0
0
0
0
0
0
0
0
0
0
0
0
J4 –3 ¼ 8.0 Hz, J4 –5 ¼7.5 Hz, J4 –6 ¼1.6 Hz); 7.52 (dd, 1H,
J3 –4 ¼8.1 Hz, J3 –5 ¼1.1 Hz); 7.70 (dt, 1H, H-5 , J5 –4
¼
H-60, J6 –5 ¼7.5 Hz, J6 –4 ¼1.6 Hz); 4.93 (dd, 1H, H-5,
J5–4a¼12.8 Hz, J5–4b¼6.1 Hz); 4.21 (c, 2H, –COO–CH2–
CH3, J¼7.1 Hz); 3.47 (dd, 1H, H-4a, J4a–4b¼18.7 Hz,
J4a–5¼ 12.9 Hz); 3.38 (m, 1H, H-1cyclobut.); 3.24 (dd, 1H,
7.7 Hz, J5 –6 ¼7.4 Hz, J5 –3 ¼1.1 Hz); 7.61 (m, 3H, H-4 ,
0
0
0
0
0
0
0
0
0
H-2, H-6benz.); 7.49 (dd, 1H, H-60, J6 –5 ¼7.4 Hz, J6 –4
¼
¼
0
0
0
0
1.5 Hz); 7.39 (tt, 1H, H-4benz., J4-3benz.¼6.7 Hz, J4-2benz.
1.2 Hz); 7.25 (pt, 2H, H-3, H-5benz., J3-2benz.¼7.1 Hz,

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4061
J3-4benz.¼6.7 Hz); 5.17 (dd, 1H, H-5, J5–4a¼12.7 Hz,
J5–4b¼6.2 Hz); 4.26 (c, 2H, –COO–CH2–CH3,
(–OCH3); 37.76 (C-4); 27.33 (–CO–CH2–CH3); 14.13
(–COO–CH2–CH3); 8.91 (–CO–CH2–CH3). HR LSIMS
calcd for C17H21N3O5Na (MþNa)þ 370.1378, found
370.1377. Anal. for C17H21N3O5: calcd: C, 58.78; H,
6.09; N, 12.10. Found: C, 59.15; H, 6.27; N, 11.81.
J¼7.1 Hz); 3.57 (dd, 1H, H-4a, J4a–4b¼18.6 Hz, J4a–5
12.7 Hz); 3.33 (dd, 1H, H-4b, J4b–4a¼18.6 Hz, J4b–5
¼
¼
6.2 Hz); 0.97 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz). 13C
NMR (75 MHz, CDCl3) d 187.29 (Ph–CO–); 168.89,
167.33 (–COO–CH2–CH3, –N–CO–); 153.34 (C-3);
148.26 (C-20); 134.30 (C-50); 134.02 (C-10); 131.97
(C-1benz.); 131.84, 131.42 (C-4benz., C-40); 129.86 (C-2,
C-6benz.); 129.36 (C-60); 127.67 (C-3, C-5benz.); 123.90
(C-30); 62.26 (–COO–CH2–CH3); 60.36 (C-5); 34.83
(C-4); 14.09 (–COO–CH2–CH3). HR LSIMS calcd for
C20H17N3O6Na (MþNa)þ 418.1015, found: 418.1014.
4.1.2.1.3. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-
butyryl-D2-pyrazoline-5-carboxylate 22a. Orange solid;
1
yield 80%; mp 153–155 8C; H NMR (300 MHz, CDCl3)
0
0
d 8.04 (d, 1H, H-60, J6 –4 ¼2.9 Hz); 7.02 (dd, 1H, H-4 ,
0
0
9.0 Hz); 6.07 (bs, 2H, –NH2); 4.90 (dd, 1H, H-5, J5–4a
0
0
0
0
0
0
J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.65 (d, 1H, H-3 , J3 –4
¼
¼
12.9 Hz, J5–4b¼6.3 Hz); 4.20 (c, 2H, –COO–CH2–CH3,
J¼7.1 Hz); 3.77 (s, 3H, –OCH3); 3.59 (dd, 1H, H-4a,
J4a–4b¼18.8 Hz, J4a–5¼12.9 Hz); 3.29 (dd, 1H, H-4b,
J4b–4a¼18.8 Hz, J4b,5¼6.3 Hz); 2.80 (pq, 1H, –CO–
CH2–CH2–CH3, Ha, Jgem¼15.1 Hz, JHa–CH2¼7.5 Hz);
2.68 (pq, 1H, –CO–CH2–CH2–CH3, Hb, Jgem¼15.1 Hz,
JHb–CH2¼7.5 Hz); 1.74 (m, 2H, –CO–CH2–CH2–CH3);
1.28 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz); 0.97 (t, 3H,
–CO–CH2–CH2–CH3, J¼7.4 Hz).13C NMR (75 MHz,
CDCl3) d 186.43 (Ph–CO–); 172.64 (–N–CO–); 169.61
(–COO–CH2–CH3); 153.70 (C-3); 150.14 (C-50); 146.93
(C-200); 125.52 (C-40); 118.63 (C-30); 116.12 (C-10); 114.23
(C-6 ); 62.06 (–COO–CH2–CH3); 57.47 (C-5); 55.71
(–OCH3); 37.79 (C-4); 35.83 (–CO–CH2–CH2–CH3);
18.30, (–CO–CH2–CH2–CH3); 14.14, 13.85 (–COO–
CH2–CH3, –CO–CH2–CH2–CH3). HR LSIMS calcd for
C18H23N3O5Na (MþNa)þ 384.1535, found: 384.1537.
Anal. for C18H23N3O5: calcd: C, 59.82; H, 6.41; N, 11.63.
Found: C, 59.45; H, 6.46; N, 11.53.
4.1.2. Final products
4.1.2.1. General procedure for the preparation of
compounds 20a–28a. A mixture of nitroarenes 11a–19a
(0.512 mmol) and 10% Pd/C (20 mg) was dissolved in
methanol (30 mL) and stirred under a hydrogen atmosphere
(70 psi) for 1.5 h. The mixture was filtered through celite
and evaporated. The resultant residue was dissolved in
CH2Cl2, and this solution was washed with water, dried
(Na2SO4), and concentrated. The resultant solid was
dissolved and purified by flash chromatography (ether–
hexane 1:2).
4.1.2.1.1. Ethyl 1-acetyl-3-(2-amino-5-methoxybenzoyl)-
D2-pyrazoline-5-carboxylate 20a. Orange solid; yield 80%;
mp 210–212 8C. 1H NMR (300 MHz, CDCl3) d 8.04 (d, 1H,
0
H-60, J6 –4 ¼2.9 Hz); 7.02 (dd, 1H, H-4 , J4 –3 ¼9.0 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.9 Hz); 6.65 (d, 1H, H-3 , J3 –4 ¼9.0 Hz); 6.04 (bs,
2H, –NH2); 4.90 (dd, 1H, H-5, J5–4a¼12.8 Hz, J5–4b
¼
6.2 Hz); 4.23 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.76
(s, 3H, –OCH3); 3.61 (dd, 1H, H-4a, J4a–4b¼18.8 Hz,
J4a–5¼12.8 Hz); 3.31 (dd, 1H, H-4b, J4b–4a¼18.8 Hz,
J4b,5¼6.2 Hz); 2.41 (s, 3H, –CO–CH3); 1.29 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz). 13C NMR (75 MHz,
CDCl3) d 186.37 (Ph–CO–); 169.93, 169.51 (–N–CO–,
–COO–CH2–CH3); 153.89 (C-3); 150.13 (C-50); 146.90
(C-200); 125.47 (C-40); 118.62 (C-30); 116.10 (C-10); 114.31
(C-6 ); 62.13 (–COO–CH2–CH3); 57.44 (C-5); 55.74
(–OCH3); 38.05 (C-4); 21.52 (–CO–CH3); 14.14
4.1.2.1.4. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-penta-
noyl-D2-pyrazoline-5-carboxylate 23a. Orange solid; yield
80%; mp 108–110 8C. 1H NMR (400 MHz, CDCl3) d 8.03
(d, 1H, H-60, J6 –4 ¼2.9 Hz); 7.01 (dd, 1H, H-40,
0
0
0
9.0 Hz); 6.07 (bs, 2H, –NH2); 4.89 (dd, 1H, H-5, J5–4a
0
0
0
0
0
0
J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.64 (d, 1H, H-3 , J3 –4
¼
¼
12.8 Hz, J5–4b¼6.3 Hz); 4.22 (c, 2H, –COO–CH2–CH3,
J¼7.1 Hz); 3.76 (s, 3H, –OCH3); 3.58 (dd, 1H, H-4a,
J4a–4b¼18.8 Hz, J4a–5¼12.8 Hz); 3.28 (dd, 1H, H-4b,
J4b–4a¼18.8 Hz, J4b,5¼6.3 Hz); 2.81 (pq, 1H, –CO–
(–COO–CH2–CH3).
HR
LSIMS
calcd
for
CH2–CH2–CH2–CH3, Ha, Jgem¼15.3 Hz, JHa–CH2¼
C16H19N3O5Na (MþNa)þ 356.1222, found 356.1223.
Anal. for C16H19N3O5: calcd: C, 57.65; H, 5.75; N, 12.61.
Found: C, 57.46; H, 5.70; N, 12.21.
7.6 Hz); 2.70 (pq, 1H, –CO–CH2–CH2–CH2–CH3, Hb,
Jgem¼15.3 Hz, JHb–CH2¼7.6 Hz); 1.69 (m, 2H, –CO–
CH2–CH2–CH2–CH3); 1.40 (m, 2H, –CO–CH2–CH2–
CH2–CH3) 1.27 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz);
0.91 (t, 3H, –CO–CH2–CH2–CH2–CH3, J¼7.3 Hz).13C
NMR (75 MHz, CDCl3) d 186.44 (Ph–CO–); 172.77 (–N–
CO–); 169.60 (–COO–CH2–CH3); 153.67 (C-3); 150.13
(C-500); 146.92 (C-20); 125.45 (C-40); 118.61 (C-30); 116.14
(C-1 ); 114.33 (C-60); 62.04 (–COO–CH2–CH3); 57.49
(C-5); 55.71 (–OCH3); 37.78 (C-4); 33.67 (–CO–CH2–
CH2–CH2–CH3); 26.84 (–CO–CH2–CH2–CH2–CH3);
22.46 (–CO–CH2–CH2–CH2–CH3); 14.12, 13.85
(–COO–CH2–CH3, –CO–CH2–CH2–CH2–CH3). HR
LSIMS calcd for C19H25N3O5Na (MþNa)þ 398.1691,
found 398.1692. Anal. for C19H25N3O5: calcd: C, 60.79;
H, 6.71; N, 11.90. Found: C, 60.47; H, 6.86; N, 11.55.
4.1.2.1.2. Ethyl 3-(2-amino-5-methoxybenzoyl)- 1-pro-
pionyl-D2-pyrazoline-5-carboxylate 21a. Orange solid;
1
yield 80%; mp 140–141 8C; H NMR (300 MHz, CDCl3)
0
0
d 8.03 (d, 1H, H-60, J6 –4 ¼3.0 Hz); 7.02 (dd, 1H, H-4 ,
0
0
9.0 Hz); 6.06 (bs, 2H, –NH2); 4.90 (dd, 1H, H-5, J5–4a
0
0
0
0
0
0
J4 –3 ¼9.0 Hz, J4 –6 ¼3.0 Hz); 6.64 (d, 1H, H-3 , J3 –4
¼
¼
12.8 Hz, J5–4b¼6.3 Hz); 4.23 (c, 2H, –COO–CH2–CH3,
J¼7.1 Hz); 3.76 (s, 3H, –OCH3); 3.59 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.8 Hz); 3.28 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b,5¼6.3 Hz); 2.78 (m, 2H, –CO–CH2–
CH3); 1.28 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz); 1.21 (t,
3H, –CO–CH2–CH3, J¼7.5 Hz). 13C NMR (75 MHz,
CDCl3) d 186.45 (Ph–CO–); 173.42 (–N–CO–); 169.62
(–COO–CH2–CH3); 153.70 (C-3); 150.12 (C-50); 146.88
(C-200); 125.42 (C-40); 118.61 (C-30); 116.48 (C-10); 114.30
(C-6 ); 62.06 (–COO–CH2–CH3); 57.52 (C-5); 55.71
4.1.2.1.5. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-cyclo-
propanecarbonyl-D2-pyrazoline-5-carboxylate 24a. Orange
1
solid; yield 84%; mp 118–120 8C. H NMR (300 MHz,

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4062
CDCl3) d 8.02 (d, 1H, H-60, J6 –4 ¼2.9 Hz); 7.01 (dd, 1H,
C20H25N3O5: calcd: C, 62.00; H, 6.50; N, 10.85. Found:
C, 61.71; H, 6.70; N, 10.86.
0
0
H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.65 (d, 1H, H-3 ,
0
0
0
0
0
0
0
J3 –4 ¼9.0 Hz); 6.03 (bs, 2H, –NH2); 4.90 (dd, 1H, H-5,
J5–4a¼12.8 Hz, J5–4b¼6.5 Hz); 4.22 (m, 2H, –COO–
CH2–CH3); 3.73 (s, 3H, –OCH3); 3.60 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.8 Hz); 3.30 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b,5¼6.5 Hz); 2.57 (m, 1H, H-1cycloprop.);
1.28 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz); 1.16–1.06,
0.92–0.87 (2m, 4H, H-2, H-3cycloprop.).13C NMR (75 MHz,
CDCl3) d186.77 (Ph–CO–); 173.20 (–N–CO–); 169.60
(–COO–CH2–CH3); 153.62 (C-3); 150.07 (C-50);
146.73 (C-20); 125.25 (C-40); 118.56 (C-30); 116.26
(C-10); 114.61 (C-60); 62.01 (–COO–CH2–CH3); 57.93
(C-5); 55.66 (–OCH3); 37.63 (C-4); 14.13 (–COO–CH2–
CH3); 11.84 (C-1cycloprop.); 9.10, 9.01 (C-2, C-3cycloprop.).
HR LSIMS calcd for C18H21N3O5Na (MþNa)þ
382.1378, found 382.1376. Anal. for C18H21N3O5: calcd:
C, 60.16; H, 5.89; N, 11.69. Found: C, 60.51; H, 5.66; N,
12.02.
4.1.2.1.8. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-cyclo-
hexanecarbonyl-D2-pyrazoline-5-carboxylate 27a. Orange
solid; yield 82%; mp 1270–129 8C. H NMR (300 MHz,
1
0
0
CDCl3) d 8.01 (d, 1H, H-6 , J6 –4 ¼2.9 Hz); 7.02 (dd, 1H,
H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.65 (d, 1H, H-3 ,
0
0
0
0
0
0
0
J3 –4 ¼9.0 Hz); 6.07 (bs, 2H, –NH2); 4.89 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (m, 2H, –COO–
CH2–CH3); 3.78 (s, 3H, –OCH3); 3.57 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.26 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b,5¼6.2 Hz); 3.15 (tt, 1H, H-1cyclohex.
,
Jtransdiaxial¼11.6 Hz, Jcis¼3.5 Hz); 2.02–1.46 (m, 10H, H-2,
H-3, H-4, H-5, H-6cyclohex.); 1.26 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz). 13C NMR (75 MHz, CDCl3) d 186.62 (Ph–CO–);
175.61 (–N–CO–); 169.62 (–COO–CH2–CH3); 153.63
(C-3); 150.18 (C-500); 146.91 (C-200); 125.50 (C-40); 118.60
(C-30); 116.18 (C-1 ); 114.47 (C-6 ); 61.97 (–COO–CH2–
CH3); 57.48 (C-5); 55.89 (–OCH3); 41.54 (C-1cyclohex.);
37.53 (C-4); 28.98, 28.50 (C-2, C-6cyclohex.); 25.83, 25.76,
25.59 (C-3, C-4, C-5cyclohex.); 14.13 (–COO–CH2–CH3).
HR LSIMS calcd for C21H27N3O5Na (MþNa)þ 424.1848,
found 424.1845. Anal. for C21H27N3O5: calcd: C, 62.83; H,
6.78; N, 10.47. Found: C, 62.46; H, 6.85; N, 10.41.
4.1.2.1.6. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-cyclo-
butanecarbonyl-D2-pyrazoline-5-carboxylate 25a. Orange
1
solid; yield 82%; mp 1120–114 8C. H NMR (300 MHz,
0
0
CDCl3) d 7.97 (d, 1H, H-6 , J6 –4 ¼2.9 Hz); 7.02 (dd, 1H,
H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.65 (d, 1H, H-3 ,
0
0
0
0
0
0
0
J3 –4 ¼9.0 Hz); 6.03 (bs, 2H, –NH2); 4.89 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.23 (c, 2H, –COO–CH2–
CH3, J¼7.1 Hz); 3.82 (m, 1H, H-1cyclobut.); 3.80 (s, 3H,
4.1.2.1.9. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-ben-
zoyl-D2-pyrazoline-5-carboxylate (28a). Orange solid;
1
–OCH3); 3.56 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.9 Hz); 3.26 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b,5
¼
¼
yield 82%; mp 118–120 8C. H NMR (300 MHz, CDCl3)
d 7.86 (m, 3H, H-60, H-2benz., H-6benz.); 7.42 (m, 3H,
H-3benz., H-4benz., H-5benz.); 6.94 (dd, 1H, H-40, J4 –3
¼
0
0
6.2 Hz); 2.44–2.13, 2.05–1.88 (2m, 6H, H-2, H-3,
H-4cyclobut.); 1.29 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz).
13C NMR (75 MHz, CDCl3) d 186.72 (Ph–CO–); 174.17
(–N–CO–); 169.62 (–COO–CH2–CH3); 153.55 (C-3);
150.17 (C-500); 146.93 (C-20); 125.52 (C-40); 118.54 (C-30);
116.34 (C-1 ); 114.89 (C-60); 62.06 (–COO–CH2–CH3);
57.57 (C-5); 55.85 (–OCH3); 37.64 (C-1cyclobut.); 37.56
(C-4); 25.22, 24.61 (C-2, C-4cyclobut.); 18.49 (C-3cyclobut.);
14.14 (–COO–CH2–CH3). HR LSIMS calcd for
C19H23N3O5Na (MþNa)þ 396.1535, found 396.1533.
Anal. for C19H23N3O5: calcd: C, 61.11; H, 6.21; N, 11.25.
Found: C, 60.79; H, 6.43; N, 11.30.
0
0
0
0
0
9.0 Hz, J4 –6 ¼2.9 Hz); 6.61 (d, 1H, H-3 , J3 –4 ¼9.0 Hz);
5.12 (dd, 1H, H-5, J5–4a¼12.7 Hz, J5–4b¼6.5 Hz); 4.28 (m,
2H, –COO–CH2–CH3); 3.64 (dd, 1H, H-4a, J4a–4b
18.7 Hz, J4b–5¼12.7 Hz); 3.36 (dd, 1H, H-4b, J4b–4a
¼
¼
18.7 Hz, J4b–5¼6.5 Hz); 3.26 (s, 3H, –OCH3); 1.31 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz). 13C NMR (75 MHz,
CDCl3) d 186.17 (Ph–CO–); 169.54, 168.19 (–COO–
CH2–CH3, –N–CO–); 154.66 (C-3); 150.17 (C-50); 146.86
(C-20); 133.20 (C-1benz.); 131.55 (C-4benz.); 129.72 (C-2benz.
,
C-6benz.); 128.01 (C-3benz., C-5benz.); 125.73 (C-40); 118.56
(C-30); 116.02 (C-10); 114.04 (C-60); 62.15 (–COO–CH2–
CH3); 58.53 (C-5); 55.44 (–OCH3); 37.38 (C-4); 14.17
(–COO–CH2–CH3). HR LSIMS calcd for C21H21N3O5Na
(MþNa)þ 418.1378, found 418.1377. Anal. for
C21H21N3O5: calcd: C, 63.79; H, 5.35; N, 10.63. Found:
C, 63.51; H, 5.49; N, 10.70.
4.1.2.1.7. Ethyl 3-(2-amino-5-methoxybenzoyl)-1-cyclo-
pentanecarbonyl-D2-pyrazoline-5-carboxylate 26a. Orange
1
solid; yield 84%; mp 1250–127 8C. H NMR (300 MHz,
0
0
CDCl3) d 8.03 (d, 1H, H-6 , J6 –4 ¼2.9 Hz); 7.02 (dd, 1H,
H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.64 (d, 1H, H-3 ,
0
0
0
0
0
0
0
J3 –4 ¼9.0 Hz); 6.03 (sa, 2H, –NH2); 4.90 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.21 (m, 2H, –COO–
CH2–CH3); 3.76 (s, 3H, –OCH3); 3.58 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.51 (m, 1H, H-1cyclopent.);
3.27 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b,5¼6.2 Hz); 1.91–
1.54 (m, 8H, H-2, H-3, H-4, H-5cyclopent.); 1.27 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz). 13C NMR (75 MHz,
CDCl3) d 186.63 (Ph–CO–); 175.69 (–N–CO–); 169.65
(–COO–CH2–CH3); 153.51 (C-3); 150.14 (C-50); 146.88
(C-200); 125.45 (C-40); 118.62 (C-30); 116.23 (C-10); 114.38
(C-6 ); 61.99 (–COO–CH2–CH3); 57.60 (C-5); 55.69
(–OCH3); 42.37 (C-1cyclopent.); 37.60 (C-4); 30.26, 29.47
(C-2, C-5cyclopent.); 26.17, 26.06 (C-3, C-4cyclopent.); 14.13
(–COO–CH2–CH3). HR LSIMS calcd for: C20H25N3O5Na
(MþNa)þ 410.1691, found 410.1695. Anal. for
4.1.2.2. General procedure for the preparation of
compounds 20b,c–28b,c. To a suspension of the corre-
sponding nitroarene 11b,c–19b,c (0.524 mmol) in refluxing
water was added Fe (0.29 g, 5.24 mmol) and FeSO4 (0.15 g,
0.524 mmol). The reaction mixture was refluxed for 3 h,
filtered through Celite, and washed thoroughly with
CH2Cl2. The aqueous phase was extracted with CH2Cl2
(3£15 mL) and EtOAc (3£15 mL). The organic phase was
washed with brine, dried (Na2SO4), and evaporated. The
residue was recrystallized from CH2Cl2/hexane.
4.1.2.2.1. Ethyl 1-acetyl-3-(2-amino-5-chlorobenzoyl)-
D2-pyrazoline-5-carboxylate 20b. Orange solid; yield
95%; mp 193–195 8C. 1H NMR (400 MHz, CDCl3) d
0
8.48 (d, 1H, H-60, J6 –4 ¼2.4 Hz); 7.25 (dd, 1H, H-4 ,
0
0

´
M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4063
J4 –3 ¼8.8 Hz, J4 –6 ¼2.4 Hz); 6.64 (d, 1H, H-30,
noyl-D2-pyrazoline-5-carboxylate 23b. Orange solid; yield
95%; mp 108–110 8C. 1H NMR (300 MHz, CDCl3) d 8.48
0
0
0
0
0
0
J3 –4 ¼8.8 Hz); 6.28 (bs, 2H, –NH2); 4.91 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼ 6.3 Hz); 4.24 (c, 2H, –COO–CH2–
CH3, J¼7.1 Hz); 3.61 (dd, 1H, H-4a, J4a–4b¼18.7 Hz,
J4a–5¼12.9 Hz); 3.29 (dd, 1H, H-4b, J4b–4a¼18.7 Hz,
J4b–5¼6.3 Hz); 2.40 (s, 3H, –CO–CH3); 1.29 (t, 3H, –
COO–CH2–CH3, J¼ 7.1 Hz).13C NMR (100 MHz, CDCl3)
d 186.15 (Ph–CO–); 170.21, 169.41 (–N–CO–, –COO–
CH2–CH3); 153.06 (C-3); 150.07 (C-20); 135.13 (C-40);
132.64 (C-60); 120.48 (C-50); 118.52 (C-30); 116.91 (C-10);
62.18 (–COO–CH2–CH3); 57.59 (C-5); 37.69 (C-4); 21.46
(–CO–CH3); 14.11 (–COO–CH2–CH3). HR LSIMS calcd
for C15H17ClN3O4 (Mþþ1) 338.0907, found 338.0906.
Anal. for C15H16ClN3O4: calcd: C, 53.34; H, 4.77; N, 12.44.
Found: C, 52.99; H, 4.59; N, 12.15.
(d, 1H, H-60, J6 –4 ¼2.4 Hz); 7.24 (dd, 1H, H-40,
0
0
0
8.8 Hz); 6.28 (bs, 2H, –NH2); 4.90 (dd, 1H, H-5, J5–4a
0
0
0
0
0
0
J4 –3 ¼8.8 Hz, J4 –6 ¼2.4 Hz); 6.64 (d, 1H, H-3 , J3 –4
¼
¼
12.9 Hz, J5–4b¼6.3 Hz); 4.23 (c, 2H, –COO–CH2–CH3,
J¼7.1 Hz); 3.56 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.9 Hz); 3.26 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.3 Hz); 2.83 (pq, 1H, –CO–CH2–CH2–CH2–CH3, Ha,
Jgem¼14.9 Hz, JHa–CH2¼7.7 Hz); 2.70 (pq, 1H, –CO–
CH2–CH2–CH2–CH3, Hb, Jgem¼14.9 Hz, JHb–CH2
¼
7.7 Hz); 1.71 (m, 2H, –CO–CH2–CH2–CH2–CH3);
1.45 (m, 2H, –CO–CH2–CH2–CH2–CH3); 1.28 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 0.94 (t, 3H, –CO–CH2–
CH2–CH2–CH3, J¼7.3 Hz). 13C NMR (75 MHz, CDCl3) d
186.25 (Ph–CO–); 173.18 (–N–CO–);0 169.48 (–COO–
CH2–CH3); 152.83 (C-3); 150.05 (C-2 ); 135.08 (C-40);
132.70 (C-60); 120.50 (C-50); 118.52 (C-30); 116.99 (C-10);
62.11 (–COO–CH2–CH3); 57.67 (C-5); 37.44 (C-4); 33.86
(–CO–CH2–CH2–CH2–CH3); 27.17 (–CO–CH2–CH2–
CH2–CH3); 22.54 (–CO–CH2–CH2–CH2–CH3); 14.12,
13.84 (–COO–CH2–CH3, –CO–CH2–CH2–CH2–CH3).
HR LSIMS calcd for C18H22ClN3O4Na (MþNa)þ
402.1196, found 402.1199. Anal. for C18H22ClN3O4:
calcd: C, 56.92; H, 5.84; N, 11.06. Found: C, 56.52; H,
5.95; N, 10.92.
4.1.2.2.2. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-propionyl-
D2-pyrazoline-5-carboxylate 21b. Orange solid; yield 95%;
mp 148–150 8C. 1H NMR (300 MHz, CDCl3) d 8.46 (d, 1H,
0
H-60, J6 –4 ¼2.5 Hz); 7.24 (dd, 1H, H-4 , J4 –3 ¼8.9 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.5 Hz); 6.63 (d, 1H, H-3 , J3 –4 ¼ 8.9 Hz); 6.28 (bs,
2H, –NH2); 4.90 (dd, 1H, H-5, J5–4a¼12.8 Hz, J5–4b
¼
6.3 Hz); 4.23 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.55
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼ 12.8 Hz); 3.25 (dd,
1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼ 6.3 Hz); 2.79 (m, 2H,
–CO–CH2–CH3); 1.28 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz); 1.24 (t, 3H, –CO–CH2–CH3, J¼7.5 Hz).13C
NMR (75 MHz, CDCl3) d 186.27 (Ph–CO–); 173.73 (–N–
CO–); 169.52 (–COO–CH2–CH3); 152.84 (C-3); 150.05
(C-200); 135.08 (C-40); 132.69 (C-60); 120.47 (C-50); 118.52
(C-3 ); 116.98 (C-10); 62.12 (–COO–CH2–CH3); 57.72
(C-5); 37.42 (C-4); 27.41 (–CO–CH2–CH3); 14.12
(–COO–CH2–CH3); 8.88 (–CO–CH2–CH3). HR LSIMS
calcd for C16H18ClN3O4Na (MþNa)þ 374.0883, found
374.0882. Anal. for C16H18ClN3O4: calcd: C, 54.63; H,
5.16; N, 11.94 Found: C, 54.26; H, 4.76; N, 11.66.
4.1.2.2.5. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-cyclo-
propanecarbonyl-D2-pyrazoline-5-carboxylate 24b. Orange
1
solid; yield 97%; mp 1550–157 8C. H NMR (300 MHz,
0
0
CDCl3) d 8.50 (d, 1H, H-6 , J6 –4 ¼2.4 Hz); 7.24 (dd, 1H,
H-40, J4 –3 ¼8.8 Hz, J4 –6 ¼2.3 Hz); 6.63 (d, 1H, H-3 ,
0
0
0
0
0
0
0
J3 –4 ¼8.8 Hz); 6.28 (bs, 2H, –NH2); 4.91 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼6.6 Hz); 4.22 (m, 2H, –COO–
CH2–CH3); 3.57 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.9 Hz); 3.28 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.6 Hz); 2.57 (m, 1H, H-1cycloprop.); 1.28 (t, 3H, –COO–
CH2–CH3, J¼7.1 Hz); 1.08, 0.98 (2m, H-2, H-3cycloprop.).
13C NMR (75 MHz, CDCl3) d 186.41 (Ph–CO–); 173.43
(–N–CO–); 169.52 (–COO–CH2–CH3); 152.96 (C-3);
150.01 (C-200); 135.03 (C-40); 132.75 (C-60); 120.46 (C-50);
118.50 (C-3 ); 117.07 (C-10); 62.06 (–COO–CH2–CH3);
58.08 (C-5); 37.32 (C-4); 14.13 (–COO–CH2–CH3); 11.92
(C-1cycloprop.); 9.32, 9.24 (C-2, C-3cycloprop.). HR LSIMS:
calcd for C17H18ClN3O4Na (MþNa)þ 386.0883; found:
386.0885. Anal. for C17H18ClN3O4: calcd: C, 56.13; H,
4.99; N, 11.55. Found: C, 55.96; H, 4.85; N, 11.44.
4.1.2.2.3. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-butyryl-
D2-pyrazoline-5-carboxylate 22b. Orange solid; yield 95%;
mp 144–146 8C; 1H NMR (400 MHz, CDCl3) d 8.49 (d, 1H,
0
H-60, J6 –4 ¼2.4 Hz); 7.26 (dd, 1H, H-4 , J4 –3 ¼8.8 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.4 Hz); 6.65 (d, 1H, H-3 , J3 –4 ¼8.8 Hz); 6.27 (bs,
2H, –NH2); 4.92 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b
¼
6.2 Hz); 4.24 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.57
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.27 (dd,
1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.82 (pq, 1H,
–CO–CH2–CH2–CH3, Ha, Jgem¼14.9 Hz, JHa–CH2
¼
7.3 Hz); 2.69 (pq, 1H, –CO–CH2–CH2–CH3, Hb,
Jgem¼14.9 Hz, JHb–CH2¼7.3 Hz); 1.79 (m, 2H, –CO–
CH2–CH2–CH3); 1.29 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz); 1.04 (t, 3H, –CO–CH2–CH2–CH3, J¼7.4 Hz).
13C NMR (75.57 MHz, CDCl3) d 186.26 (Ph–CO–);
173.03 (–N–CO–); 169.48 (–COO–CH2–CH3); 152.82
(C-3); 150.04 (C-200); 135.08 (C-400); 132.72 (C-60); 120.50
(C-50); 118.51 (C-3 ); 116.98 (C-1 ); 62.11 (–COO–CH2–
CH3); 57.66 (C-5); 37.42 (C-4); 36.02 (–CO–CH2–CH2–
CH3); 18.66 (–CO–CH2–CH2–CH3); 14.11, 13.94
(–COO–CH2–CH3, –CO–CH2–CH2–CH3). HR LSIMS
calcd for C17H20ClN3O4Na (MþNa)þ 388.1040, found
388.1041. Anal. for C17H20ClN3O4: calcd: C, 55.82; H,
5.51; N, 11.49 Found: C, 55.47; H, 5.44; N, 11.27.
4.1.2.2.6. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-cyclo-
butanecarbonyl-D2-pyrazoline-5-carboxylate 25b. Orange
1
solid; yield 96%; mp 1340–136 8C. H NMR (400 MHz,
0
0
CDCl3) d 8.47 (d, 1H, H-6 , J6 –4 ¼2.5 Hz); 7.26 (dd, 1H,
H-40, J4 –3 ¼8.8 Hz, J4 –6 ¼2.5 Hz); 6.64 (d, 1H, H-3 ,
0
0
0
0
0
0
0
J3 –4 ¼8.8 Hz); 6.25 (bs, 2H, –NH2); 4.90 (dd, 1H, H-5,
J5–4a¼12.9 Hz, J5–4b¼6.2 Hz); 4.24 (m, 2H, –COO–
CH2–CH3); 3.79 (m, 1H, H-1cyclobut.); 3.54 (dd, 1H, H-4a,
J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.24 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.47–1.89 (m, 6H, H-2,
H-3, H-4cyclobut.); 1.30 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz). 13C NMR (100 MHz, CDCl3) d 186.30 (Ph–CO–);
174.43 (–N–CO–); 169.51 (–COO–CH2–CH3); 152.69 (C-
3); 149.98 (C-20); 135.01 (C-40); 132.77 (C-60); 120.46 (C-50);
118.48 (C-30); 117.00 (C-10); 62.10 (–COO–CH2–CH3);
4.1.2.2.4. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-penta-

´
M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4064
57.75 (C-5); 37.87 (C-1cyclobut.); 37.16 (C-4); 25.17, 24.41
(C-2, C-4cyclobut.); 18.37 (C-3cyclobut.); 14.13 (–COO–CH2–
CH3). HR LSIMS calcd for C18H20ClN3O4Na (MþNa)þ
400.1040, found 400.1040. Anal. for C18H20ClN3O4: calcd:
C, 55.52; H, 5.34; N, 11.12. Found: C, 57.11; H, 5.62; N,
10.87.
3H, –COO–CH2–CH3, J¼7.1 Hz). 13C NMR (75 MHz,
CDCl3): d 185.90 (Ph–CO–); 169.48 (–COO–CH2–CH3);
167.87 (–N–CO–); 153.95 (C-3); 150.09 (C-20); 135.11
(C-40); 133.48 (C-1benz.); 132.53 (C-60); 131.93 (C-4benz.);
129.89 (C-2, C-6benz.); 128.26 (C-3, C-5benz.); 120.54 (C-50);
118.52 (C-30); 116.88 (C-10); 62.22 (–COO–CH2–CH3);
58.83 (C-5); 36.84 (C-4); 14.18 (–COO–CH2–CH3). HR
LSIMS calcd for C20H18ClN3O4Na (MþNa)þ 422.0883,
found 422.0881. Anal. for C20H18ClN3O4: calcd: C, 60.08;
H, 4.54; N, 10.51. Found: C, 59.80; H, 4.17; N, 10.46.
4.1.2.2.7. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-
cyclopentanecarbonyl-D2-pyrazoline-5-carboxylate
26b.
Orange solid; yield 96%; mp 135–137 8C. 1H NMR
(300 MHz, CDCl3) d 8.50 (d, 1H, H-60, J6 –4 ¼2.5 Hz);
0
0
7.24 (dd, 1H, H-40, J4 –3 ¼8.9 Hz, J4 –6 ¼2.5 Hz); 6.63 (d,
4.1.2.2.10. Ethyl 1-acetyl-3-(2-aminobenzoyl)-D2-pyra-
zoline-5-carboxylate 20c. Yellow solid; yield 95%;
0
0
0
0
1H, H-30, J3 –4 ¼8.9 Hz); 4.90 (dd, 1H, H-5, J5–4a
¼
0
0
1
12.9 Hz, J5–4b¼6.2 Hz); 4.22 (m, 2H, –COO–CH2–
mp100–102 8C. H NMR (300 MHz, CDCl3) d 8.34 (dd,
1H, H-60, J6 –5 ¼8.2 Hz, J6 –4 ¼1.5 Hz); 7.28 (ddd, 1H,
0
0
0
0
CH3); 3.55 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
¼
H-40, J4 –3 ¼8.4 Hz, J4 –5 ¼7.0 Hz, J4 –6 ¼1.5 Hz); 6.71 (d,
0
0
0
0
0
0
12.9 Hz); 3.47 (m, 1H, H-1cyclopent.); 3.24 (dd, 1H, H-4b,
J4b–4a¼18.7 Hz, J4b–5¼6.2 Hz); 2.11–1.58 (m, 8H, H-2,
H-3, H-4, H-5cyclopent.); 1.28 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz). 13C NMR (75 MHz, CDCl3) d 186.46 (Ph–CO–);
175.86 (–N–CO–); 169.54 (–COO–CH2–CH3); 152.44
(C-3)0 ; 150.00 (C-200); 135.00 (C-400); 132.87 (C-60); 120.57
(C-5 ); 118.50 (C-3 ); 117.16 (C-1 ); 62.05 (–COO–CH2–
CH3); 57.89 (C-5); 42.62 (C-1cyclopent.); 37.21 (C-4); 30.11,
29.30 (C-2, C-5cyclopent.); 26.26, 26.14 (C-3, C-4cyclopent.);
14.13 (–COO–CH2–CH3). HR LSIMS calcd for C19H22-
ClN3O4Na (MþNa)þ 414.1196, found 414.1194. Anal. for
C19H22ClN3O4: calcd: C, 58.24; H, 5.66; N, 10.72. Found:
C, 58.08; H, 5.92; N, 10.70.
1H, H-30, J3 –4 ¼8.4 Hz); 6.69 (dd, 1H, H-5 , J5 –6 ¼8.2 Hz,
0
0
0
0
0
0
0
J5 –4 ¼7.0 Hz); 4.90 (dd, 1H, H-5, J5–4a¼12.8 Hz, J5–4b
¼
6.1 Hz); 4.23 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.60
(dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.8 Hz); 3.27
(dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 2.40 (s,
3H, –CO–CH3); 1.28 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz). 13C NMR (75 MHz, CDCl3) d 187.53 (Ph–CO–);
170.12, 169.51 (–N–CO–, –COO–CH2–CH3); 153.38
(C-3); 151.20 (C-200); 135.25 (C-400); 133.62 (C-60); 117.31
(C-30); 116.92 (C-1 ); 116.31 (C-5 ); 62.08 (–COO–CH2–
CH3); 57.52 (C-5); 37.90 (C-4); 21.46 (–CO–CH3); 14.12
(–COO–CH2–CH3). HR LSIMS calcd for C15H17N3O4Na
(MþNa)þ 326.1116, found 326.1116). Anal. for
C15H17N3O4: calcd: C, 59.40; H, 5.65; N, 13.85. Found:
C, 59.77; H, 5.60; N, 14.25.
4.1.2.2.8. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-cyclo-
hexanecarbonyl-D2-pyrazoline-5-carboxylate 27b. Orange
1
solid; yield 95%; mp 1350–137 8C. H NMR (300 MHz,
CDCl3) d 8.55 (d, 1H, H-6 , J6 –4 ¼2.4 Hz); 7.25 (dd, 1H,
4.1.2.2.11. Ethyl 3-(2-aminobenzoyl)-1-propionyl-D2-
pyrazoline-5-carboxylate 21c. Yellow solid; yield 95%;
0
0
H-40, J4 –3 ¼8.8 Hz, J4 –6 ¼2.4 Hz); 6.64 (d, 1H, H-3 ,
0
0
0
0
0
1
0
0
J3 –4 ¼8.8 Hz); 6.26 (bs, 2H, –NH2); 4.88 (dd, 1H, H-5,
J5–4a¼12.8 Hz, J5–4b¼6.1 Hz); 4.21 (m, 2H, –COO–
mp132–133 8C. H NMR (300 MHz, CDCl3) d 8.34 (dd,
1H, H-60, J6 –5 ¼8.2 Hz, J6 –4 ¼1.5 Hz); 7.32 (ddd, 1H,
0
0
0
0
H-40, J4 –3 ¼8.5 Hz, J4 –5 ¼7.0 Hz, J4 –6 ¼1.5 Hz); 6.72 (d,
0
0
0
0
0
0
CH2–CH3); 3.53 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.8 Hz); 3.24 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
1H, H-30, J3 –4 ¼8.5 Hz); 6.70 (ddd, 1H, H-5 , J5 –6
¼
0
0
0
0
0
0
0
0
0
6.1 Hz); 3.11 (tt, 1H, H-1cyclohex., Jtransdiaxial¼11.5 Hz,
Jcis¼3.4 Hz); 2.05–1.19 (m, 10H, H-2, H-3, H-4, H-5,
H-6cyclohex.); 1.27 (t, 3H, –COO–CH2–CH3, J¼
7.2 Hz).13C NMR (75 MHz, CDCl3) d 186.20 (Ph–CO–);
175.79 (–N–CO–); 169.49 (–COO–CH2–CH3); 152.67
(C-3)0 ; 150.07 (C-200); 135.01 (C-400); 132.79 (C-60); 120.58
(C-5 ); 118.50 (C-3 ); 117.14 (C-1 ); 62.02 (–COO–CH2–
CH3); 57.75 (C-5); 42.11 (C-1cyclohex.); 37.19 (C-4); 28.60,
28.58 (C-2, C-6cyclohex.); 25.95, 25.89, 25.68 (C-3, C-4,
C-5cyclohex.); 14.12 (–COO–CH2–CH3). HR LSIMS calcd
for C20H24ClN3O4Na (MþNa)þ 428.1355, found 428.1353.
Anal. for C20H24ClN3O4: calcd: C, 59.18; H, 5.96; N, 10.35.
Found: C, 58.80; H, 5.62; N, 10.05.
8.2 Hz, J5 –4 ¼7.0 Hz, J5 –3 ¼1.1 Hz); 4.90 (dd, 1H, H-5,
J5–4a¼12.8 Hz, J5–4b¼6.2 Hz); 4.23 (c, 2H, –COO–CH2–
CH3, J¼7.1 Hz); 3.58 (dd, 1H, H-4a, J4a–4b¼18.7 Hz,
J4a–5¼12.8 Hz); 3.25 (dd, 1H, H-4b, J4b–4a¼18.7 Hz,
J4b–5¼6.2 Hz); 2.77 (m, 2H, –CO–CH2–CH3); 1.28 (t,
3H, –COO–CH2–CH3, J¼7.1 Hz); 1.20 (t, 3H, –CO–
CH2–CH3, J¼7.5 Hz).13C NMR (75 MHz, CDCl3) d
187.62 (Ph–CO–); 173.60 (–N–CO–),0 169.61 (–COO–
CH2–CH3); 153.14 (C-3); 150.92 (C-2 ); 135.19 (C-40);
133.62 (C-60); 117.41 (C-30); 117.13 (C-10); 116.45 (C-50);
62.02 (–COO–CH2–CH3); 57.64 (C-5); 37.59 (C-4); 27.27
(–CO–CH2–CH3); 14.11 (–COO–CH2–CH3); 8.75
(–CO–CH2–CH3). HR LSIMS calcd for C16H19N3O4Na
(MþNa)þ 340.1273, found 340.1273. Anal. for
C16H19N3O4: calcd: C, 60.56; H, 6.03; N, 13.24. Found:
C, 60.26; H, 6.32; N, 13.13.
4.1.2.2.9. Ethyl 3-(2-amino-5-chlorobenzoyl)-1-benzoyl-
D2-pyrazoline-5-carboxylate 28b. Orange solid; yield 95%;
1
mp 181–183 8C. H NMR (300 MHz, CDCl3) d 8.47 (d,
1H, H-60, J6 –4 ¼2.4 Hz); 7.96 (dd, 2H, H-2benz., H-6benz.
,
4.1.2.2.12. Ethyl 3-(2-aminobenzoyl)-1-butyryl-D2-pyra-
zoline-5-carboxylate 22c. Yellow solid; yield 95%; mp
0
0
J2-3benz.¼7.4 Hz, J2-4benz.¼1.6 Hz); 7.50 (m, 3H, H-3,
H-4benz., H-5benz.); 7.20 (dd, 1H, H-40, J4 –3 ¼8.9 Hz,
90–92 8C. 1H NMR (400 MHz, CDCl3) d 8.33 (d, 1H, H-600,
0
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.4 Hz); 6.59 (d, 1H, H-3 , J3 –4 ¼8.9 Hz); 6.25
(bs, 2H, –NH2); 5.14 (dd, 1H, H-5, J5–4a¼12.8 Hz,
J5–4b¼6.4 Hz); 4.28 (m, 2H, –COO–CH2–CH3); 3.61
(dd, 1H, H-4a, J4a–4b¼18.8 Hz, J4a–5¼12.8 Hz); 3.32
(dd, 1H, H-4b, J4b–4a¼18.8 Hz, J4b–5¼6.4 Hz); 1.31 (t,
J6 –5 ¼8.2 Hz); 7.28 (m, H-4 ); 6.67 (d, 1H, H-3 ,
0
0
0
J3 –4 ¼8.6 Hz); 6.66 (m, H-5 ); 6.26 (bs, 2H, –NH2); 4.90
(dd, 1H, H-5, J5–4a¼12.8 Hz, J5–4b¼6.1 Hz); 4.22 (c, 2H,
–COO–CH2–CH3, J¼7.1 Hz); 3.57 (dd, 1H, H-4a,
J4a–4b¼18.6 Hz, J4a–5¼12.8 Hz); 3.25 (dd, 1H, H-4b,

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4065
J4b–4a¼18.6 Hz, J4b–5¼6.1 Hz); 2.78 (pq, 1H, Ha, –CO–
CH2–CH2–CH3, Jgem¼15.0 Hz, JHa–CH2¼7.4 Hz); 2.66
(pq, 1H, Hb, –CO–CH2–CH2–CH3, Jgem¼15.0 Hz,
JHb–CH2¼7.4 Hz); 1.74 (m, 2H, –CO–CH2–CH2–CH3);
1.27 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz); 0.99 (t, 3H,
–CO–CH2–CH2–CH3, J¼7.4 Hz). 13C NMR (100 MHz,
CDCl3) d 187.59 (Ph–CO–); 172.85 (–N–CO–), 169.60
(–COO–CH2–CH3); 153.15 (C-3); 151.64 (C-20); 135.20
(C-400); 133.62 (C-60); 117.31 (C-30); 116.65 (C-10); 115.95
(C-5 ); 61.99 (–COO–CH2–CH3); 57.54 (C-5); 37.63
(C-4); 35.68 (–CO–CH2–CH2–CH3); 18.36 (–CO–
CH2–CH2–CH3) 14.09, 13.83 (–COO–CH2–CH3,
(MþNa)þ 352.1269, found 352.1273. Anal. for
C17H19N3O4: calcd: C, 62.00; H, 5.81; N, 12.76. Found:
C, 61.81; H, 6.20; N, 12.62.
4.1.2.2.15. Ethyl 3-(2-aminobenzoyl)-1-cyclobutane-
carbonyl-D2-pyrazoline-5-carboxylate 25c. Yellow solid;
yield 96%; mp 104–106 8C. 1H NMR (400 MHz, CDCl3) d
0
8.31 (d, 1H, H-60, J6 –5 ¼7.6 Hz); 7.31 (m, 1H, H-4 ); 6.68
0
0
(d, 1H, H-30, J3 –4 ¼7.9 Hz); 6.67 (m, 1H, H-5 ); 6.22 (bs,
0
0
0
2H, –NH2); 4.89 (dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b
¼
6.1 Hz); 4.23 (c, 2H, –COO–CH2–CH3, J¼7.1 Hz); 3.77
(m, 1H, H-1cyclobut.); 3.55 (dd, 1H, H-4a, J4a–4b¼18.6 Hz,
J4a–5¼12.9 Hz); 3.23 (dd, 1H, H-4b, J4b–4a¼18.6 Hz,
J4b–5¼6.1 Hz); 2.46–2.16, 2.04–1.85 (m, 6H, H-2, H-3,
H-4cyclobut.); 1.29 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz).
13C NMR (100 MHz, CDCl3) d 186.72 (Ph–CO–); 174.17
(–N–CO–), 169.62 (–COO–CH2–CH3); 153.03 (C-3);
151.57 (C-200); 135.19 (C-40); 133.75 (C-60); 117.08 (C-30);
116.78 (C-1 ); 115.93 (C-50); 62.01 (–COO–CH2–CH3);
57.66 (C-5); 37.69 (C-1cyclobut.); 37.40 (C-4); 25.15, 24.48
(C-2, C-4cyclobut.); 18.33 (C-3cyclobut.); 14.13 (–COO–
CH2–CH3). HR LSIMS calcd for C18H21N3O4Na
(MþNa)þ 366.1429, found 366.1430. Anal. for
C18H21N3O4: calcd: C, 62.96; H, 6.16; N, 12.24. Found:
C, 62.59; H, 6.19; N, 12.14.
–CO–CH2–CH2–CH3).
HR
LSIMS
calcd
for
C17H21N3O4Na (MþNa)þ 354.1429, found 354.1433.
Anal. for C17H21N3O4: calcd: C, 61.62; H, 6.39; N, 12.68.
Found: C, 61.24; H, 6.45; N, 12.63.
4.1.2.2.13. Ethyl 3-(2-aminobenzoyl)-1-pentanoyl-D2-
pyrazoline-5-carboxylate 23c. Yellow solid; yield 95%;
1
mp 88–90 8C. H NMR (400 MHz, CDCl3) d 8.35 (d, 1H,
0
0
0
H-60, J6 –5 ¼8.2 Hz); 7.30 (m, H-4 ); 6.68 (d, 1H, H-3 ,
0
0
7.1 Hz); 6.24 (bs, 2H, –NH2); 4.90 (dd, 1H, H-5,
0
0
0
0
0
0
J3 –4 ¼8.4 Hz); 6.66 (pt, 1H, H-5 , J5 –6 ¼8.2 Hz, J5 –4
¼
J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.22 (c, 2H, –COO–
CH2–CH3, J¼7.1 Hz); 3.58 (dd, 1H, H-4a, J4a–4b
18.7 Hz, J4a–5¼12.9 Hz); 3.25 (dd, 1H, H-4b, J4b–4a
¼
¼
18.7 Hz, J4b–5¼6.1 Hz); 2.80 (pq, 1H, Ha, –CO–CH2–
CH2–CH2–CH3, Jgem¼15.0 Hz, JHa–CH2¼7.6 Hz); 2.68
(pq, 1H, Hb, –CO–CH2–CH2–CH2–CH3, Jgem¼15.0 Hz,
JHb–CH2¼7.6 Hz); 1.70 (m, 2H, –CO–CH2–CH2–CH2–
CH3); 1.40 (m, 2H, –CO–CH2–CH2–CH2–CH3); 1.28 (t,
3H, –COO–CH2–CH3, J¼7.1 Hz); 0.92 (t, 3H, –CO–
CH2–CH2–CH2–CH3, J¼7.3 Hz). 13C NMR (100 MHz,
CDCl3) d 187.61 (Ph–CO–); 173.05 (–N–CO–), 169.60
(–COO–CH2–CH3); 153.15 (C-3); 0 151.63 (C-200);
135.22 (C-40); 133.66 (C-60); 117.11 (C-3 ); 116.70 (C-1 );
115.97 (C-50); 62.01 (–COO–CH2–CH3); 57.56 (C-5);
37.65 (C-4); 33.62 (–CO–CH2–CH2–CH2–CH3); 27.03
(–CO–CH2–CH2–CH2–CH3) 22.44 (–CO–CH2–CH2–
CH2–CH3); 14.11, 13.87 (–COO–CH2–CH3, –CO–CH2–
CH2–CH2–CH3). HR LSIMS calcd for C18H23N3O4Na
(MþNa)þ 368.1586, found 368.1589. Anal. for
C18H23N3O4: calcd: C, 62.59; H, 6.71; N, 12.17. Found:
C, 62.24; H, 6.90; N, 12.13.
4.1.2.2.16. Ethyl 3-(2-aminobenzoyl)-1-cyclopentane-
carbonyl-D2-pyrazoline-5-carboxylate 26c. Yellow solid;
yield 96%; mp 118–120 8C. 1H NMR (400 MHz, CDCl3) d
0
1H NMR (400 MHz, CDCl3) d 8.33 (d, 1H, H-6 , J6 –5
¼
0
0
8.1 Hz); 7.30 (m, 1H, H-40); 6.68 (d, 1H, H-30, J3 4
¼
0
0
8.3 Hz); 6.66 (m, 1H, H-50); 6.22 (bs, 2H, –NH2); 4.90
(dd, 1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.1 Hz); 4.21 (m, 2H,
–COO–CH2–CH3); 3.57 (dd, 1H, H-4a, J4a–4b¼18.6 Hz,
J4a–5¼12.9 Hz); 3.47 (m, 1H, H-1cyclopent.); 3.24 (dd, 1H,
H-4b, J4b–4a¼18.6 Hz, J4b–5¼6.1 Hz); 2.04–1.55 (m, 8H,
H-2, H-3, H-4, H-5cyclopent.); 1.27 (t, 3H, –COO–CH2–
CH3, J¼7.1 Hz). 13C NMR (100 MHz, CDCl3) d 186.72
(Ph–CO–); 175.69 (–N–CO–), 169.65 (–COO–CH2–
CH3); 152.85 (C-3); 151.58 (C-20); 135.15 (C-40); 133.69
(C-60); 117.09 (C-30); 116.78 (C-10); 115.93 (C-50); 61.93
(–COO–CH2–CH3); 57.71 (C-5); 42.23 (C-1cyclopent.);
37.42 (C-4); 30.06, 29.35 (C-2, C-5cyclopent.); 26.33, 26.20
(C-3, C-4cyclopent.); 14.10 (–COO–CH2–CH3). HR LSIMS
calcd for C19H23N3O4Na (MþNa)þ 380.1586, found
380.1585. Anal. for C19H23N3O4: calcd: C, 63.85; H,
6.49; N, 11.76. Found: C, 63.63; H, 6.58; N, 11.76.
4.1.2.2.14. Ethyl 3-(2-aminobenzoyl)-1-cyclopropane-
carbonyl-D2-pyrazoline-5-carboxylate 24c. Yellow solid;
1
yield 95%; mp 88–90 8C. H NMR (300 MHz, CDCl3) d
8.38 (dd, 1H, H-60, J6 –5 ¼8.8 Hz, J6 –4 ¼1.6 Hz); 7.30
0
0
0
0
4.1.2.2.17. Ethyl 3-(2-aminobenzoyl)-1-cyclohexane-
carbonyl-D2-pyrazoline-5-carboxylate 27c. Yellow solid;
yield 96%; mp 117–119 8C. 1H NMR (400 MHz, CDCl3) d
(ddd, 1H, H-40, J4 –3 ¼8.3 Hz, J4 –5 ¼7.0 Hz, J4 –6
¼
0
0
0
0
0
0
1.6 Hz); 6.67 (m, H-50); 6.24 (bs, 2H, –NH2); 4.90 (dd,
1H, H-5, J5–4a¼12.9 Hz, J5–4b¼6.4 Hz); 4.22 (m, 2H,
–COO–CH2–CH3); 3.60 (dd, 1H, H-4a, J4a–4b¼18.6 Hz,
J4a–5¼12.8 Hz); 3.27 (dd, 1H, H-4b, J4b–4a¼18.6 Hz,
J4b–5¼6.4 Hz); 2.55 (m, 1H, H-1cycloprop.); 1.27 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 1.15–1.05, 0.96–0.89 (2m,
4H, H-2, H-3cycloprop.). 13C NMR (75 MHz, CDCl3) d
187.74 (Ph–CO–); 173.34 (–N–CO–),0 169.63 (–COO–
CH2–CH3); 153.36 (C-3); 151.58 (C-2 ); 135.17 (C-40);
133.73 (C-60); 117.08 (C-30); 116.78 (C-10); 116.02 (C-50);
61.97 (–COO–CH2–CH3); 57.94 (C-5); 37.55 (C-4); 14.12
(–COO–CH2–CH3); 11.80 (C-1cycloprop.); 9.27, 9.21 (C-2,
C-3cycloprop.). HR LSIMS calcd for C17H19N3O4Na
8.37 (dd, 1H, H-60, J6 –5 ¼8.2 Hz, J6 –4 ¼1.2 Hz); 7.31 (m,
0
0
0
0
1H, H-40); 6.68 (d, 1H, H-30, J3 4 ¼8.3 Hz); 6.66 (m, 1H, H-
50); 6.24 (bs, 2H, –NH2); 4.89 (dd, 1H, H-5, J5–4a¼12.9 Hz,
J5–4b¼6.1 Hz); 4.21 (m, 2H, –COO–CH2–CH3); 3.56 (dd,
1H, H-4a, J4a–4b¼18.7 Hz, J4a–5¼12.9 Hz); 3.24 (dd, 1H,
0
0
H-4b, J4b–4a¼18.7 Hz, J4b–5¼6.1 Hz); 3.08 (tt, H-1cyclohex.
,
Jtransdiaxial¼11.5 Hz, Jcis¼3.2 Hz); 2.02–1.19 (m, 10H, H-2,
H-3, H-4, H-5, H-6cyclohex.); 1.26 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz). 13C NMR (100 MHz, CDCl3) d 186.62
(Ph–CO–); 175.61 (–N–CO–), 169.72 (–COO–CH2–
CH3); 152.94 (C-3); 151.60 (C-20); 135.16 (C-40); 133.65
(C-60); 117.12 (C-30); 116.78 (C-10); 115.89 (C-50); 61.94

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M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4066
0
0
0
0
0
(–COO–CH2–CH3); 57.58 (C-5); 41.86 (C-1cyclohex.);
37.40 (C-4); 28.99, 28.52 (C-2, C-6cyclohex.); 25.91, 25.76,
25.60 (C-3, C-4, C-5cyclohex.); 14.10 (–COO–CH2–CH3).
HR LSIMS calcd for C20H25N3O4Na (MþNa)þ 394.1742,
found 394.1739. Anal. for C20H25N3O4: calcd: C, 64.67; H,
6.78; N, 11.31. Found: C, 64.44; H, 7.06; N, 11.26.
H-60, J6 –7 ¼ 9.6 Hz, J6 –4 ¼2.3 Hz); 6.99 (d, 1H, H-4 ,
0
0
J4 –6 ¼2.3 Hz); 5.03 (dd, 1H, H-5, J5–4a¼12.6 Hz, J5–4b
¼
6.0 Hz); 4.24 (c, 2H, –COO–CH2–CH3, J¼ 7.1 Hz); 3.87
(s, 3H, –OCH3); 3.78 (dd, 1H, H-4a, J4a–4b¼18.2 Hz,
J4a–5¼12.6 Hz); 3.50 (dd, 1H, H-4b, J4b–4a¼18.2 Hz,
J4b–5¼6.0 Hz); 2.86 (pq, 1H, –CO–CH2–CH2–CH3,
H-a, Jgem¼14.7 Hz, JHa–CH2¼ 7.5 Hz); 2.74 (pq, 1H,
4.1.2.2.18. Ethyl 3-(2-aminobenzoyl)-1-benzoyl-D2-
pyrazoline-5-carboxylate 28c. Yellow solid; yield 95%;
–CO–CH2–CH2–CH3, H-b, Jgem¼ 14.7 Hz, JHb–CH2¼
7.5 Hz); 1.79 (m, 2H, –CO–CH2–CH2–CH3); 1.29 (t, 3H,
–COO–CH2–CH3, J¼7.1 Hz); 1.03 (t, 3H, –CO–CH2–
CH2–CH3, J¼7.4 Hz).13C NMR (75 MHz, CDCl3) d
172.09 (–N–CO–); 169.50 (–COO–CH2–CH3); 158.12
(C-500); 155.55, 154.14 (C-3, C-70a);0 144.11 (C-30); 128.59
(C-6 ); 117.43 (C-30a); 117.10 (C-7 ); 94.85 (C-40); 62.18
(–COO–CH2–CH3); 57.44 (C-5); 55.46 (–OCH3); 37.01
(–CO–CH2–CH2–CH3); 36.03 (C-4); 18.49 (–CO–CH2–
CH2–CH3); 14.14, 14.11 (–COO–CH2–CH3, –CO–CH2–
CH2–CH3). HR LSIMS calcd for C18H21N3O5Na (MþNa)þ
382.1378, found 382.1379. Anal. for C18H21N3O5: calcd: C,
60.16; H, 5.89; N, 11.69. Found: C, 60.38; H, 6.19; N, 11.35.
1
mp 125–127 8C. H NMR (300 MHz, CDCl3) d 8.32 (dd,
1H, H-60, J6 –5 ¼8.3 Hz, J6 –4 ¼1.2 Hz); 7.95 (dd, 2H, H-2,
0
0
0
0
H-6benz., J2-3benz.¼7.1 Hz, J2-4benz.¼1.5 Hz); 7.46 (m, 3H,
H-40, H-3, H-5benz.); 7.27 (m, 1H, H-4benz.); 6.65 (d, 1H, H-
0
30, J3 4 ¼8.3 Hz); 6.56 (pt, 1H, H-5 , J5 –6 ¼8.3 Hz, J5 –4
¼
0
0
0
0
0
0
7.0 Hz); 6.24 (sa, 2H, –NH2); 5.13 (dd, 1H, H-5, J5–4a
¼
12.8 Hz, J5–4b¼6.4 Hz); 4.27 (c, 2H, –COO–CH2–CH3,
J¼7.1 Hz); 3.64 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.8 Hz); 3.32 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
6.4 Hz); 1.31 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz). 13C
NMR (75 MHz, CDCl3) d 187.34 (Ph–CO–); 169.56
(–COO–CH2–CH3); 167.67 (–N–CO–); 154.18 (C-3);
151.68 (C-20); 135.23 (C-40); 133.70 (C-60); 132.83
(C-1benz.); 131.84 (C-4benz.); 130.13 (C-2, C-6benz.);
127.89 (C-3, C-5benz.); 117.08 (C-30);116.70 (C-10); 115.99
(C-50); 62.11 (–COO–CH2–CH3); 58.52 (C-5); 37.12
(C-4); 14.17 (–COO–CH2–CH3). HR LSIMS calcd for
C20H19N3O4Na (MþNa)þ 388.1273, found 388.1273. Anal.
for C20H25N3O4: calcd: C, 65.74; H, 5.24; N, 11.50. Found:
C, 65.41; H, 4.97; N, 11.42.
4.1.2.4. General procedure for the preparation of
compounds 31 and 32. A mixture of nitroarene 21a or 24a
(0.512 mmol) and 10% Pd/C (60 mg) was dissolved in
methanol (30 mL) and stirred under a hydrogen atmosphere
(70 psi) for 5 h. The mixture was filtered through celite and
evaporated. The resultant residue was dissolved in CH2Cl2,
and this solution was washed with water, dried (Na2SO4),
and concentrated. The resultant solid was dissolved and
purified by flash chromatography (ethyl acetate–hexane
1:3).
4.1.2.3. General procedure for the preparation of
compounds 29 and 30. A mixture of nitroarene 20a or 22a
(0.511 mmol) and SnCl2 (2.55 mmol) was dissolved in
ethanol and was stirred under reflux for 1 h. The solution
was neutralized to pH¼7 with NaHCO3, extracted with
ethyl acetate (2£15 mL), and dried (Na2SO4). Evaporation
of the solvent gave a residue which was recrystallized from
CH2Cl2–hexane.
4.1.2.4.1. Ethyl 5-(2-amino-5-methoxybenzoyl)-2-pro-
pionylpyrazolidine-3-carboxylate4 31. Orange solid; yield
20%; mp 81–83 8C. 1H NMR (400 MHz, CDCl3) d 7.00 (s,
1H, H-60); 7.02 (dd, 1H, H-40, J4 –3 ¼8.9 Hz, J4 –6
¼
0
0
0
0
2.8 Hz); 6.66 (d, 1H, H-30, J3 –4 ¼8.9 Hz); 6.06 (bs, 2H,
–NH2); 5.33 (d, 1H, H-1, J1–5¼11.7 Hz); 4.96 (dd, 1H,
H-3, J3–4a¼9.2 Hz, J3–4b¼6.5 Hz); 4.59 (m, 1H, H-5); 4.17
(m, 2H, –COO–CH2–CH3); 3.76 (s, 3H, –OCH3); 2.93
0
0
4.1.2.3.1. Ethyl 1-acetyl-3-(5-methoxybenzo[c]isoxazol-
3-yl)-D2-pyrazoline-5-carboxylate 29. Orange solid; yield
100%; mp 156–158 8C. 1H NMR (300 MHz, CDCl3) d 7.55
(ddd, 1H, H-4a, J4a–4b¼13.0 Hz, J4a–3¼9.2 Hz, J4a–5¼
8.0 Hz); 2.61 (m, 2H, –CO–CH2–CH3); 2.12 (ddd, 1H,
H-4b, J4b–4a¼13.0 Hz, J4b–5¼9.4 Hz, J4b–3¼6.5 Hz); 1.24
(t, 3H, –COO–CH2–CH3, J¼7.1 Hz); 1.14 (t, 3H, –CO–
CH2–CH3, J¼7.5 Hz).13C NMR (75 MHz, CDCl3) d
196.09 (Ph–CO–); 175.13 (–N–CO–); 0171.33 (–COO–
CH2–CH3); 150.29 (C-50); 146.50 (C-2 ); 124.91 (C-40);
119.14 (C-30); 114.99 (C-10); 112.45 (C-60); 62.69 (C-5);
61.69 (–COO–CH2–CH3); 58.06 (C-3); 56.15 (–OCH3);
37.97 (C-4); 26.95 (–CO–CH2–CH3); 14.17 (–COO–
CH2–CH3); 9.15 (–CO–CH2–CH3). HR LSIMS calcd for
C17H23N3O5Na (MþNa)þ 372.1535, found 372.1534. Anal.
for C17H23N3O5: calcd: C, 58.44; H, 6.64; N, 12.03. Found:
C, 58.06; H, 6.35; N, 12.27.
0
(d, 1H, H-70, J7 –6 ¼9.5 Hz); 7.09 (dd, 1H, H-6 , J6 –7
¼
0
0
0
0
0
0
0
0
0
9.5 Hz, J6 –4 ¼2.2 Hz); 6.98 (d, 1H, H-4 , J4 –6 ¼2.2 Hz);
5.03 (dd, 1H, H-5, J5–4a¼12.6 Hz, J5–4b¼6.0 Hz); 4.25 (c,
2H, –COO–CH2–CH3, J¼7.1 Hz); 3.87 (s, 3H, –OCH3);
3.79 (dd, 1H, H-4a, J4a–4b¼18.2 Hz, J4a–5¼12.6 Hz); 3.51
(dd, 1H, H-4b, J4b–4a¼18.2 Hz, J4b–5¼6.0 Hz); 2.47 (s, 3H,
–CO–CH3); 1.30 (t, 3H, –COO–CH2–CH3, J¼
7.1 Hz).13C NMR (75 MHz, CDCl3) d 169.43, 169.36
(–COO–CH2–CH3, –N–CO–); 158.15 (C-50); 155.57,
154.97 (C-3, C-70a);0 144.35 (C-300); 128.63 (C-60); 117.46
(C-30a); 117.09 (C-7 ); 94.81 (C-4 ); 62.25 (–COO–CH2–
CH3); 57.35 (C-5); 55.52 (–OCH3); 37.28 (C-4); 21.41
(–CO–CH3); 14.15 (–COO–CH2–CH3). HR LSIMS calcd
for C16H17N3O5Na (MþNa)þ 354.1069, found 354.1065.
Anal. for C16H17N3O5: calcd: C, 58.00; H, 5.17; N, 12.68.
Found: C, 57.68; H, 5.13; N, 12.49.
4.1.2.4.2. Ethyl 5-(2-amino-5-methoxybenzoyl)-2-cyclo-
propanecarbonylpyrazolidine-3-carboxylate 32. Orange
solid; yield 19%; mp 780–80 8C. 1H NMR (400 MHz,
0
0
CDCl3) d 7.19 (d, 1H, H-6 , J6 –4 ¼2.8 Hz); 7.02 (dd, 1H,
0
0
0
0
0
4.1.2.3.2. Ethyl 1-butyryl-3-(5-methoxybenzo[c]isoxa-
zol-3-yl)-D2-pyrazoline-5-carboxylate 30. Orange solid;
yield 100%; mp 144–1046 8C. 1H NMR (300 MHz,
H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.8 Hz); 6.68 (d, 1H, H-3 ,
0
0
J3 –4 ¼9.0 Hz); 6.03 (bs, 2H, –NH2); 5.13 (d, 1H, H-1,
J1–5¼8.7 Hz); 4.98 (m, 1H, H-5); 4.74 (dd, 1H, H-3, J3–4a
¼
0
0
CDCl3) d 7.55 (d, 1H, H-7 , J7 –6 ¼9.6 Hz); 7.09 (dd, 1H,
9.4 Hz, J3–4b¼3.6 Hz); 4.23 (c, 2H, –COO–CH2–CH3,

´
M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4067
J¼7.1 Hz); 3.77 (s, 3H, –OCH3); 2.64 (m, 1H, H-4a); 2.40
(m, 2H, H-4b, H-1cycloprop.); 1.29 (t, 3H, –COO–CH2–CH3,
J¼7.1 Hz); 1.00–0.66 (m, 4H, H-2, H-3cycloprop.). 13C NMR
(100 MHz, CDCl3) d 196.50 (Ph–CO–); 174.44 (–N–CO–);
171.96 (–COO–CH2–CH3); 150.08 (C-50); 146.40 (C-20);
124.36 (C-40); 118.95 (C-30); 115.44 (C-10); 113.40 (C-60);
61.79 (C-5); 61.53 (–COO–CH2–CH3); 59.00 (C-3); 56.16
(–OCH3); 36.89 (C-4); 14.20 (–COO–CH2–CH3); 11.54
(C-1cycloprop.); 8.19, 8.06 (C-2, C-3cycloprop.). HR LSIMS:
calcd for C18H23N3O5Na (MþNa)þ 384.1535, found
384.1539. Anal. for C18H23N3O5: calcd: C, 59.82; H,
6.41; N, 11.63. Found: C, 59.43; H, 6.05; N, 11.29.
(dd, 1H, H-5, J5–4a¼12.6 Hz, J5–4b¼5.8 Hz); 3.75 (s, 3H,
–OCH3); 3.58 (dd, 1H, H-4a, J4a–4b¼18.7 Hz, J4a–5
12.6 Hz); 3.23 (dd, 1H, H-4b, J4b–4a¼18.7 Hz, J4b–5
¼
¼
5.8 Hz); 2.38 (s, 3H, –CO–CH3). 13C NMR (75 MHz,
CD3OD) d 188.39 (Ph–CO–); 176.99 (–COOH); 172.11
(–N–CO–); 156.57 (C-3)0; 150.98 (C-50); 148.90 (C-200);
126.16 (C-40); 119.48 (C-3 ); 117.05 (C-10); 115.46 (C-6 );
61.40 (C-5); 56.23 (–OCH3); 39.86 (C-4); 21.78 (–CO–
CH3). HR LSIMS calcd for C14H14DN3O5Na (MþNa)þ
329.0970, found 329.0972. Anal. for C14H15N3O5: calcd: C,
55.08; H, 4.95; N, 13.76. Found: C, 54.72; H, 4.55; N, 13.36.
4.1.2.6.2.
hexanecarbonyl-D2-pyrazoline-5-carboxylic
3-(2-Amino-5-methoxybenzoyl)-1-cyclo-
acid 35.
4.1.2.5. Synthesis of ethyl 3-(2-amino-5-methoxy-a-
hydroxybencyl)-1-benzoyl-D2-pyrazoline-5-carboxylate
33. A mixture of nitroarene 28a (0.512 mmol) and 10% Pd/
C (80 mg) was dissolved in methanol (30 mL) and stirred
under a hydrogen atmosphere (70 psi) for 7.5 h. The mixture
was filtered through celite and evaporated. The resultant
residue was dissolved in CH2Cl2, and this solution was
washed with water, dried (Na2SO4), and concentrated. The
resultant solid was dissolved and purified by flash
chromatography (ethyl acetate–hexane 1:2) to give 33:
Orange solid; yield 41%; mp 276–278 8C. 1H NMR
(300 MHz, CD3OD) d 8.03 (d, 1H, H-60, J6 –4 ¼2.9 Hz);
0
0
7.00 Hz (dd, 1H, H-40, J4 –3 ¼9.0 Hz, J4 –6 ¼2.9 Hz); 6.74
0
0
0
0
(d, 1H, H-30, J3 –4 ¼9.0 Hz); 4.71 (dd, 1H, H-5, J5–4a
¼
0
0
12.6 Hz, J5–4b¼ 5.9 Hz); 3.78 (s, 3H, –OCH3); 3.57 (dd,
1H, H-4a, J4a–4b¼ 18.6 Hz, J4a–5¼12.6 Hz); 3.30 (m, 1H,
H-1cyclohex.); 3.21 (dd, 1H, H-4b, J4b–4a¼18.6 Hz, J4b–5
¼
5.9 Hz); 2.05–1.73 (m, 5H, Hec. cyclohex.); 1.54–1.27 (m,
5H, Hax. cyclohex.). 13C NMR (75 MHz, CD3OD) d 188.72
(Ph–CO–); 177.360 (–N–CO–); 176.99 (–COOH); 156.24
(C-3); 151.04 (C-5 )0; 148.78 (C-20);0 126.01 (C-40); 119.45
(C-30); 117.28 (C-1 ); 115.46 (C-6 ); 61.56 (C-5); 56.49
(–OCH3); 42.98 (C-1cyclohex.); 39.33 (C-4); 30.22, 29.63
(C-2, C-6cyclohex.); 27.06, 26.92, 26.82 (C-3, C-4,
C-5cyclohex.). HR LSIMS: calcd for C19H23N3O5Na
(MþNa)þ 396.1529, found 396.1535. Anal. for
C19H23N3O5: calcd: C, 61.11; H, 6.21; N, 11.25. Found:
C, 60.81; H, 5.95; N, 10.87.
1
87 mg (43% yield); white solid; mp 74–76 8C. H NMR
(400 MHz, CDCl3) d 7.87 (dd, 2H, H-2, H-6benz., J2-3benz.
¼
7.1 Hz, J2-4benz.¼1.4 Hz); 7.47 (tt, 1H, H-4benz., J4-3benz.
¼
7.4, J4-2benz.¼1.4 Hz); 7.43 (pt, 2H, H-3, H-5benz.
,
J3-4benz.¼7.4 Hz, J3-2benz.¼7.1 Hz); 6.78 (d, 1H, H-60,
J6 –4 ¼2.9 Hz); 6.73 (dd, 1H, H-40, J4 –3 ¼8.6 Hz,
0
0
0
0
0
0
0
0
0
J4 –6 ¼2.9 Hz); 6.62 (d, 1H, H-3 , J3 –4 ¼8.6 Hz); 5.46 (s,
1H, –CH–OH); 5.02 (dd, 1H, H-5, J5–4a¼12.2 Hz,
J5–4b¼6.0 Hz); 4.18 (m, 1H, –COO–CH2–CH3); 3.74 (s,
3H, –OCH3); 3.19 (dd, 1H, H-4a, J4a–4b¼18.4 Hz, J4a–5
12.2 Hz); 2.81 (dd, 1H, H-4b, J4b–4a¼18.4 Hz, J4b–5
¼
¼
4.2. Biological activity
6.0 Hz); 1.22 (t, 3H, –COO–CH2–CH3, J¼7.1 Hz). 13C
NMR (100 MHz, CDCl3) d 169.84 (–COO–CH2–CH3);
166.99 (–N–CO–); 159.59 (C-3); 153.11 (C-50); 138.09
(C-20); 133.48 (C-1benz.); 131.33 (C-4benz.); 129.76 (C-2,
C-6benz.); 127.84 (C-3, C-5benz.); 124.65 (C-10); 118.83
(C-30); 115.02 (C-40); 113.43 (C-60); 70.49 (–CH–OH);
61.88 (–COO–CH2–CH3); 59.10 (C-5); 55.84 (–OCH3);
36.11 (C-4); 14.05 (–COO–CH2–CH3). HR LSIMS: calcd
for C21H23N3O5Na (MþNa)þ 420.1535, found 420.1529.
Anal. for C21H23N3O5: calcd: C, 63.46; H, 5.83; N, 10.57.
Found: C, 63.42; H, 6.17; N, 10.35.
4.2.1. Striatal nNOS activity determination. L-Arginine,
L-citrulline, N-(2-hydroxymethyl)piperazine-N-(2-hydroxy-
ropanesulfonic acid) (HEPES), DL-dithiothreitol (DTT),
leupeptin, aprotinin, pepstatin, phenylmethylsulfonyl-
fluoride (PMSF), hypoxantine-9-b-D-ribofuranosid (ino-
sine), ethylene-glycol-bis-(b-aminoethyl ether)-N,N,N,N,-
tetraacetic acid (EGTA), bovine serum albumin (BSA),
Dowex-50 W (50x8-200), FAD, NADPH and 5,6,7,8-
tetrahydro-L-biopterin dihydrocloride (H4-biopterin) were
obtained from Sigma Quımica (Spain). L-[3H]-arginine
´
(58 Ci/mmol) was obtained from Amersham (Amersham,
Bucks, UK). Tris (hydroxymethyl)-aminomethane (Tris–
HCl) and calcium chloride were obtained from Merck
(Spain).
4.1.2.6. General procedure for the preparation of
compounds 34 and 35. An aqueous solution of Na2CO3
(2 M, 1.5 mL) was added with stirring to a suspension of the
corresponding ester 20a or 27a (0.548 mmol) at 65 8C for
6 h. The reaction mixture was then cooled at room
temperature and neutralized with resin Amberlite IR-120
[Hþ], stirred carefully for 20 min, next a solution of NH4OH
(18%, 10 mL) was added and stirred for 20 min, the mixture
was filtered and the filtrate was concentrated to dryness. The
resulting residue was purified by flash chromatography
(acetone–methanol 10:1).
The rats were killed by cervical dislocation, and the striata
were quickly collected and immediately used to measure
NOS activity. Upon removal, the tissues were cooled in ice-
cold homogenizing buffer (25 mM Tris, 0.5 mM DTT,
10 mg/mL leupeptin, 10 mg/mL pepstatine, 10 mg/mL
aprotinine, 1 mM PMSF, pH 7.6). Two striata were placed
in 1.25 mL of the same buffer and homogenized in a
Polytron (10 s£6). The crude homogenate was centrifuged
for 5 min at 1000g, and aliquots of the supernatant
were either stored at 220 8C for total protein determi-
nation33 or used immediately to measure NOS activity. The
nNOS activity was measured by the Bredt and Snyder32
method, monitoring the conversion of L-[3H]-arginine to
4.1.2.6.1. 1-Acetyl-3-(2-amino-5-methoxybenzoyl)-D2-
pyrazoline-5-carboxylic acid 34. Orange solid; yield 40%;
1
mp 260–262 8C. H NMR (300 MHz, CD3OD) d 8.06 (d,
0
0
0
1H, H-60, J6 –4 ¼3.0 Hz); 6.98 (dd, 1H, H-4 , J4 –3 ¼9.1 Hz,
0
0
0
0
0
0
0
J4 –6 ¼3.0 Hz); 6.74 (d, 1H, H-3 , J3 –4 ¼9.1 Hz); 4.73

´
M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4068
L-[3H]-citrulline. The final incubation volume was 100 mL
and consisted of 10 mL crude homogenate added to a buffer
to give a final concentration of 25 mM Tris, 1 mM DTT,
30 mM H4-biopterin, 10 mM FAD, 0.5 mM inosine, 0.5 mg/
mL BSA, 0.1 mM CaCl2, 10 mM L-arginine, and 50 nM
L-[3H]-arginine, at pH 7.6. The reaction was started by the
addition of 10 mL of NADPH (0.75 mM final) and
continued for 30 min at 37 8C. Control incubations were
performed by the omision of NADPH. The reaction was
halted by the addition of 400 mL of cold 0.1 M Hepes,
10 mM EGTA, and 0.175 mg/mL L-citrulline, pH 5.5. The
reaction mixture was decanted into a 2 mL column packet
with Dowex-50 W ion-exchange resin (Naþ form) and
eluted with 1.2 mL of water. L-[3H]-Citrulline was quanti-
fied by liquid scintillation spectroscopy. The retention of
L-[3H]-arginine in this process was greater than 98%.
Specific enzyme activity was determined by subtracting the
control value, which usually amounted to less than 1% of
the radioactivity added. The nNOS activity was expressed
as picomoles of L-[3H]-citruline produced (mg of
6. Norris, P. J.; Waldvogel, H. J.; Faull, R. L.; Love, D. R.;
Emson, P. C. Decreased neuronal nitric oxide synthase
messenger RNA and somatostatin messenger RNA in the
striatum of Hungtinton’s disease. Neuroscience 1996, 4,
1037–1047.
7. Petros, A.; Bennett, D.; Vallance, P. Effect of nitric oxide
synthase inhibitors on hypotension in patients with septic
shock. Lancet 1991, 338, 1157–1158.
8. McCartney-Francis, N.; Allens, J. B.; Mizel, D. E.; Albina,
J. E.; Nathan, C. F.; Whal, S. M. Suppression of arthritis by an
inhibitor of NO synthase. J. Exp. Med. 1993, 178, 749–754.
9. Moncada, S. Nitric oxide: discovery and impact on clinical
medicine. J. R. Soc. Med. 1999, 92, 164–169.
10. Naka, M.; Nanbu, T.; Kobayashi, K.; Kamanaka, Y.; Komeno,
M.; Yanase, R.; Fukutomi, T.; Fujimara, S.; Seo, H. G.;
Fujiwara, N.; Ohuchida, S.; Susuki, K.; Kondo, K.; Taniguchi,
N. A potent inhibitor of inducible nitric oxide synthase, ONO-
1714, a cyclic amidine derivative. Biochem. Biophys. Res.
Commun. 2000, 270, 663–667.
11. Garvey, E. P.; Oplinger, J. A.; Furfine, E. S.; Kiff, R. J.;
Laszlo, F.; Whittle, B.; Knowles, R. 1400W is a slow, tight
binding, and highly selective inhibitor of inducible nitric-
oxide synthase in vitro and in vivo. J. Biol. Chem. 1997, 272,
4959–4963.
protein)21 min21
.
4.2.2. Cerebral iNOS activity determination. The induc-
tion of the enzyme was achieved by intravenous inyection of
lipopolysacharide (LPS) 10 mg/kg. Six hours after the
injection, the rat brains were removed and homogenized in
homogenizing buffer (25 mM Tris–HCl, 0.5 mM DTT,
10 mg/mL leupeptin, 10 mg/mL pepstatin, 10 mg/mL apro-
tinin, 1 mM PMSF, pH 7.6) cold (4 8C) for 0.05 mg
tissue/mL buffer.
´
´
12. Camacho, E.; Leon, J.; Carrion, A.; Entrena, A.; Escames, G.;
Khaldy, H.; Acun˜a-Castroviejo, D.; Gallo, M. A.; Espinosa, A.
Inhibition of nNOS activity in rat brain by synthetic
kynurenines: structure–activity dependence. J. Med. Chem.
2002, 45, 263–274.
13. Vallence, P.; Leiper, J. Blocking NO synthesis: how, where
and why. Drug Discov. 2002, 1, 939–950.
Once the homogenizing of the tissue has been obtained, it
was incubated in the presence of EGTA 10 mM to eliminate
the existing nNOS activity. The rest of the process followed
to measure the iNOS activity is the same as the one
described to measure the striatal nNOS activity.
14. Reiter, R. J. Pineal melatonin: cell biology of its synthesis and
of its physiological interactions. Endocrine Rev. 1991, 12,
151–180.
15. Rusak, B.; Yu, G. D. Regulation of melatonin-sensitive and
firing-rate rhythms of hamster suprachiasmatic nucleus
neurons: pinealectomy effects. Brain Res. 1993, 602,
200–204.
Acknowledgements
16. Acun˜a-Castroviejo, D.; Escames, G.; Macias, M.; Mun˜oz-
Hoyos, A.; Molina-Carballo, A.; Arauzo, M.; Montes, R.;
Vives, F. Cell protective role of melatonin in the brain.
J. Pineal Res. 1995, 19, 57–63.
´
We thank the Spanish Comision Interministerial de Ciencia
y Tecnologıa (SAF2002-01688) and from the Fondo de
´
´
Investigacion Sanitaria (PI021181) for financial support of
this work. The award of a grant from the Junta de Andalucıa
¨
17. Fauteck, J. D.; Bockmann, J.; Bockers, T. M.; Wittkowski, W.;
´
¨
¨
Koling, R.; Lucke, A.; Straub, H.; Speckmann, E. J.; Tuxhorn,
I.; Wolf, P.; Pannek, H.; Oppel, F. Melatonin reduces low
Mg2þ epileptiform activity in human temporal slices. Exp.
Brain Res. 1995, 107, 321–325.
to M.D.C.P. is gratefully acknowledged.
References and notes
18. Marco, M.; Vincenzo, P. P.; Gilberto, S.; Tarzia, G. Melatonin.
Curr. Med. Chem. 1999, 6, 501–518.
1. Hanafy, K. A.; Knumenacker, J. S.; Murad, F. NO nitro-
tyrosine and cyclic GMP in signal transduction. Med. Sci.
Monit. 2001, 7, 801–819.
19. Escames, G.; Acun˜a-Castroviejo, D.; Vives, F. Melatonin–
dopamine interaction in the striatal projection area of
sensorimotor cortex in the rat. NeuroReport 1996, 7, 597–600.
20. Pozo, D.; Reiter, R. J.; Calvo, J. R.; Guerrero, J. M.
Physiological concentrations of melatonin inhibit nitric
oxide synthase in rat cerebellum. Life Sci. 1994, 55, 455–460.
21. Bettahi, I.; Pozo, D.; Osuna, C.; Reiter, R. J.; Acun˜a-
Castroviejo, D.; Guerrero, J. Melatonin reduces nitric oxide
synthase activity in rat hipothalamus. J. Pineal Res. 1996, 20,
205–210.
2. Alderton, W. K.; Cooper, C. E.; Knowles, R. G. Nitric oxide
synthases: structure, function and inhibition. Biochem. J.
2001, 357, 593–615.
3. Bredt, D. S.; Snyder, S. H. Nitric oxide: a physiologic
messenger molecule. Annu. Rev. Biochem. 1994, 63, 175–195.
4. Yew, D. T.; Wong, H. W.; Li, W. P.; Lai, H. W.; Yu, W. H.
Nitric oxide synthase in different areas of normal aged and
Alzheimer’s brains. Neuroscience 1999, 89, 675–686.
5. Wong, N. K.; Strong, M. J. Nitric oxide synthase expression in
cervical spinal cord in sporadic amyotrophic lateral sclerosis.
Eur. J. Cell Biol. 1998, 77, 338–343.
´
22. Leon, J.; Vives, F.; Crespo, E.; Camacho, E.; Espinosa, A.;
Gallo, M. A.; Escames, G.; Acun˜a-Castroviejo, D. Modifi-
cation of nitric oxide synthase activity and neuronal response

´
M. D. Carrion et al. / Tetrahedron 60 (2004) 4051–4069
4069
in rat striatum by melatonin and kynurenine derivatives.
J. Neuroendocrinol. 1998, 10, 297–302.
´ ´
23. Leon, J.; Macıas, M.; Escames, G.; Camacho, E.; Khaldy, H.;
hydrazide and 3,4,5-trimethoxybenzoic acid hydrazide and
their possible biological activities. Indian Drugs 1999, 36,
466–469.
´
Martın, M.; Espinosa, A.; Gallo, M. A.; Acun˜a-Castroviejo, D.
28. Shimada, F.; Shiga, Y.; Morikawa, M.; Kawazura, H.;
Morikawa, O.; Matsuoka, T.; Nishizaki, T.; Saito, N. The
neuroprotective agent MS-153 stimulates glutamate uptake.
Eur. J. Pharmacol. 1999, 386(2/3), 263–270.
Structure-related inhibition of calmodulin-dependent neuronal
nitric oxide synthase activity by melatonin and synthetic
kynurenines. Mol. Pharmacol. 2000, 58, 967–975.
24. Ku¨c¸u¨kgu¨zel, S¸. G.; Rollas, S.; Erdeniz, H.; Kiraz, M.; Ekinci,
A. C. Synthesis, characterization and pharmacological proper-
ties of some 4-arylhydrazono-2-pyrazoline-5-one derivatives
obtained from heterocyclic amines. Eur. J. Med. Chem. 2000,
35, 761–771.
29. Fu¨rstner, A.; Jumbam, D.; Scidel, G. Syntheses of zindoxifene
and analogues by titanium-induced oxo-amide cupling. Chem.
Ber. 1994, 127, 1125–1130.
30. Makino, K.; Takahashi, H. The synthesis of 5-hydroxy-
kynurenine. J. Am. Chem. Soc. 1954, 76, 4994–4996.
31. Shen, W.; Coburn, C.; Bornmann, W. G.; Denishefsky, S. J.
Concise total syntheses of DL-camptothecin and related
anticancer drugs. J. Org. Chem. 1993, 58, 611–617.
32. Bredt, D. S.; Snyder, S. H. Isolation of nitric oxide
synthethase, a calmodulin requiring enzyme. Proc. Natl.
Acad. Sci. U. S. A. 1990, 87, 682.
25. Turan-Zitouni, G.; Chevallet, P.; Kilic¸, F. S.; Erol, K.
Synthesis of some thiazolyl-pirazoline derivatives and pre-
liminary investigation of their hypotesive activity. Eur. J. Med.
Chem. 2000, 35, 635–641.
26. Palaska, E.; Erol, D.; Demirdamar, R. Synthesis and
antidepressant activities of some 1,3,5-triphenyl-2-pyrazo-
lines. Eur. J. Med. Chem. 1996, 31, 43–47.
33. Lowry, O. H.; Rosebroigh, N. J.; Farr, A. S.; Randall, R. J.
Protein easurement with the folin phenol reagent. J. Biol.
Chem. 1951, 193, 265–267.
27. Solomon, W. D.; Ravi, T. K.; Annadurai, K. Synthesis of
certain substituted 1,2-pyrazolines from phenoxyacetic acid