Pyrazolo-[1,5-a]-1,3,5-triazine corticotropin-releasing factor (CRF) receptor ligands

Article abstract of DOI:10.1016/S0968-0896(03)00398-5

The syntheses and rat CRF receptor binding affinities of 'retro-pyrazolotriazine' corticotropin-releasing factor (CRF) ligands 4 are reported. Some have high affinity for rat CRF receptors (K_i≤10 nM). The data provide additional support for the hypothesis that it is possible to interchange isosteric cores with similar electronic properties in the design of high-affinity CRF receptor ligands, provided the peripheral pharmacophore elements are maintained in the same three-dimensional array.

Full text of DOI:10.1016/S0968-0896(03)00398-5

Bioorganic & Medicinal Chemistry 11 (2003) 4093–4102
Pyrazolo-[1,5-a]-1,3,5-triazine Corticotropin-Releasing
Factor (CRF) Receptor Ligands
Paul J. Gilligan,*,y Beverly K. Folmer,{ Richard A. Hartz,y Stephanie Koch,
Kausik K. Nanda,x Stephen Andreuski,k Lawrence Fitzgerald,{
Keith Miller** and William J. Marshallyy
Bristol-Myers Squibb Co., Discovery Chemistry Department and E.I. DuPont de Nemours and Co.,
Central Research and Development Department, Experimental Station, Wilmington, DE 19880-0500, USA
Received 3 March 2003; accepted 8 May 2003
Abstract—The syntheses and rat CRF receptor binding affinities of ‘retro-pyrazolotriazine’ corticotropin-releasing factor (CRF)
ligands 4 are reported. Some have high affinity for rat CRF receptors( Kiꢀ10 nM). The data provide additional support for the
hypothesis that it is possible to interchange isosteric cores with similar electronic properties in the design of high-affinity CRF
receptor ligands, provided the peripheral pharmacophore elements are maintained in the same three-dimensional array.
# 2003 Elsevier Ltd. All rights reserved.
Corticotropin-releasing factor (CRF) receptors have
become targetsfor the diegsn of potential anti-
depressant and anxiolytic drugs because of the central
role CRF playsin the regulation of the endocrine,
neural and immune responses to stress.1,2 CRF isthe
prime regulator of the hypothalamus–pituitary–adrenal
(HPA) axis, which is the physiological entity mediating
the body’s responses to stress. CRF mediates its effects
through two receptor subtypes, CRF1 and CRF2. In
rodent studies, the CRF1 receptor subtype appears to
play a greater role in stress-related responses than the
CRF2 subtype. However, additional studies with sub-
type-selective ligands are needed to definitively assign
the physiological roles of the two subtypes in rodents as
well as higher species.
Preclinical studies have established a potential role for
CRF in anxiety and depression.3,4 Intracerebroven-
tricular (icv) injection of CRF in rodentsand primates
induces a broad spectrum of electrophysiological,
immune and behavioral changes similar to those evoked
by natural stressors.5 Chronic stress in rats and non-
human primates has been shown to alter the plasticity
of the HPA axis and to cause long-term hypersensitivity
to natural stressors.6,7 The selective non-peptide
antagonist CP154526-1 has shown efficacy in rodent
8ꢁ10
modelsfor anxiety and depresion.
In clinical studies, hypersecretion of CRF has been
linked to depression and affective disorders.11ꢁ14 Eleva-
tion of plasma cortisol concentrations has been docu-
mented in many, but not all, depressed patients.
Cortisol exerts negative feedback control on the secre-
tion of CRF in the hypothalamusin normal patient;s
thisfeedback isbelieved to be defective in many
depressed patients. Hypersecretion of CRF in the cere-
brospinal fluid (CSF) parallels the hypersecretion of
cortisol. Chronic antidepressant or electroconvulsive
shock therapy ameliorates the clinical signs of depres-
sion with concomitant reductions in plasma levels of
cortisol and CSF levels of CRF. Finally, the selective
non-peptide CRF1 antagonist R121919 has shown some
efficacy in an open label clinical trial with a small group
of depressed patients, with improvements in anxiety-
related parametersbeing noted aswell. Unfortunately,
*Corresponding author. Tel.: +1-203-677-7684; fax: +1-203-677-
7702; e-mail: paul.j.gilligan@bms.com
yCurrent address: Bristol-Myers Squibb Co., 5 Research Parkway,
Wallingford, CT 06492, USA.
{Current address: Incyte Corp., Newark, DE 19714, USA.
xCurrent address: Merck Research Laboratories, West Point, PA, USA.
kCurrent address: Albany Molecular Research Inc., Albany, NY, USA.
{Current address: Pharmacia Corporation, 301 Henrietta St., Kala-
mazoo, MI, USA.
**Current address: Bristol-Myers Squibb Co., Metabolic Diseases
Research, HW21-2.03, 311 Pennington and Rocky Hill Rd., Penning-
ton, NJ 08534, USA.
yyE.I. DuPont de Nemoursand Co.
0968-0896/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0968-0896(03)00398-5

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P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
Scheme 1.
Scheme 3.
Scheme 4.
Results and Discussion
Retro-pyrazolotriazines 4 were prepared in a convergent
fashion by the couplings of pyrazoles 11 with aroyl
thioimidates 17. The requisite pyrazoles were synthe-
sized by the general methods depicted in Scheme 2.
Carboxylic acids 5 were converted to the corresponding
amides 6. Conversion of amides 6 to ketones 7 occurred
after treatment with variousGrignard reagent.s The
ketones 7 underwent a condensation with diethyl phos-
phonoacetonitrile to generate acrylonitriles 8 asa mix-
ture of E- and Z-isomers. Hydrogenation afforded
nitriles 9. Generation of the carbanion with lithium
Scheme 2.
liver toxicity precluded further evaluation of thiscom-
pound.15 Controlled double-blind clinical trialswith a
selective CRF antagonist are still needed to provide
proof of principle. Nonetheless, the case for CRF
antagonists as potential neuropsychiatric drugs is still
compelling and has inspired new efforts to discover
structurally diverse CRF antagonists.
bis(trimethylsilyl)amide
and
condensation
with
propionyl chloride provided ketonitriles 10. Subsequent
condensation with hydrazine gave the aminopyrazole
intermediates 11. The nitriles 9 could also be
prepared by nucleophilic displacement of bromides 12
This report describes the syntheses and in vitro phar-
macological properties of a novel series of CRF ligands.
Previousreportshave documented the excellent recep-
tor binding affinity of bicyclic CRF ligands, wherein
a six-membered ring is fused to a five-membered
ring (examples 1, 2 and 3, Scheme 1).1,2,16,17 In the
purine series, the interchangeability of the five- and
six-membered rings has also been examined (examples 2
and 3).18,19 We undertook the syntheses and pharmaco-
logical evaluation of a series of ‘retro-pyrazolotriazines’
4 (Scheme 1) to test whether the interchangeability of
the five- and six-membered rings was applicable to other
bicyclic cores.
with sodium cyanide. Compounds
7
where
R2=CH2CH2OMe were prepared by the reaction of
amides 6 with vinyl magnesium bromide, followed by
treatment with H2SO4 and methanol.
The thio-imidates 17 were prepared by a modification of
a published procedure (Scheme 3).20 Acids 13 were
converted to primary amides 14 by conversion to acid
chlorides and subsequent treatment with ammonium
hydroxide in dioxane. Intermediates 14 were then
condensed with dimethylformamide dimethyl acetal to
generate compounds 15. Reaction of 15 with H2S in

P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
4095
4l). Reductionsin chain length decrease binding affinity
(cf. 4e, 4f, 4m, 4o). A cyclobutyl group may replace the
propyl moiety with little effect on affinity while a 3-tetra-
hydrofuranyl group can not. Replacement of the bran-
ched alkyl sidechain CHR1R2 with cyclopentyl or
tetrahydropyranyl moietiessignificantly reducesbinding
affinity. These findings can be extended to the 2-chloro-
4-methylphenyl, 2-chloro-5-fluoro-4-methoxyphenyl and
2,4-dimethoxyphenyl cores(entries 4t–4z). Comparison
of the data for the compoundsin thispaper with those
for the literature compounds 1, 2, 3 and their ana-
logues16ꢁ18 providesadditional upsport for the
hypothesis that it is possible to interchange isosteric
cores with similar electronic properties in the design of
high affinity CRF receptor ligands, provided the per-
ipheral pharmacophore elementsare maintained in the
same three-dimensional array. The impact of changing
the cores on CRF receptor subtype binding selectivity,
functional antagonism and in vivo parameters (e.g., rat
behavioral efficacy and pharmacokinetics) is under
investigation.
Experimental
Analytical data were generated using the following pro-
cedures. Proton NMR spectra were recorded on an
Varian FT-NMR (300 MHz); chemical shifts were
recorded in ppm (d) from an internal tetramethysilane
standard in deuterochloroform or deuterodimethylsulf-
oxide as specified below. Mass spectra (MS) or high
resolution mass spectra (HRMS) were recorded on a
Finnegan MAT 8230 spectrometer (using chemi-ioni-
zation (CI) with NH3 asthe carrier gasor gaschroma-
tography (GC) asspecified below) or a Hewlett Packard
5988A model spectrometer. Melting points were recor-
ded on a Buchi Model 510 melting point apparatusand
are uncorrected. Boiling pointsare uncorrected. All pH
determinationsduring workup were made with indi-
cator paper. Combustion analyses were performed by
Quantitative Technologies, Whitehouse, NJ, USA.
Figure 1.
acetic acid provided thioimides 16. Methylation pro-
vided the thio-imidates 17, with no evidence of N-
methylation.
Condensation of pyrazoles 11 with thio-imidates 17 in
dioxane at reflux temperature provided retro-pyrazolo-
triazines 4 (Scheme 4). Only the desired regio-isomers
were formed. In the case of analogue 4e, the structure
wasconfirmed by X-ray crystallography ( Fig. 1).21
An alternate synthesis of compounds 4 wasdeviesd to
expedite SAR exploration on the phenyl substituent
(Scheme 4). Conversion of aminopyrazoles 11 to the
corresponding amidines 18 wasaccomplihsed by reac-
tion with ethyl acetamidate. Treatment of intermediates
18 with aroyl chloridesafforded targets 4 in modest
yields.
Reagents were purchased from commercial sources and,
where necessary, purified prior to use.25 Chromato-
graphy [thin-layer (TLC) or preparative] wasperformed
on silica gel using the solvent systems indicated below.
For mixed solvent systems, the volume ratios are given.
Otherwise, parts and percentages are by weight.
Compounds 4 were tested for their binding affinity to
rat CRF receptorsuinsg cortical homogenatesand
[
4-(2,4-Dichlorophenyl)-7-ethyl-2-methyl-8-(3-pentyl)-pyr-
azolo[1,5-a]-1,3,5-triazine (4e) (Method A). A mixture
of NaCN (4.1 g, 82.7 mmol) and KI (154 mg, 0.9 mmol)
in anhydrousdimethylsulfoxide (40 mL) washeated to
40 ꢂC with stirring. 3-Ethyl-1-bromobutane (12.4 g, 75.2
mmol) wasadded dropwies over 10 min. The reaction
mixture was first stirred and heated at 80 ꢂC for 1 h,
then at 120 ꢂC for 5 h. The reaction mixture wascooled
to ambient temperature and a precipitate formed. Dilu-
tion with water (150 mL), extraction with ether (3ꢃ100
mL), washing the combined organic layers with a satu-
rated NaCl solution, drying over MgSO4 and filtration
125I]-Tyr0-ovine CRF asthe radioligand. 22 The data are
summarized in Table 1. Previouswork hasetsablihs ed
that 2,4-dichlorophenyl and 2-chloro-4,5-dimethox-
yphenyl groupsenhance receptor binding affinity in this
series.23,24 Sidechain modificationswere invetsigated
initially with these two cores (Table 1). Branched alkyl
groupsat the 8-poistion of the pyrazolotriazine core
enhance binding affinity for rat CRF receptors. Pre-
1
ferred chain lengthsfor R and R2 are three to four
atoms. Propyl, methoxymethyl and methoxyethyl
chainshave comparable effectson affinity (cf. 4a, 4b, 4k,

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P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
Table 1. Rat CRF receptor binding affinity data
Example
CHR1R2
R3
R4
R5
Ki (nM)(n)a
4a
4b
4c
4d
4e
4fb
4gb
4h
4i
4j
4k
4l
4m
4n
4o
4p
4q
4r
4s
4t
4u
4v
4w
4x
4y
CHPr2
CHPr(CH2OMe)
CH(cyclobutyl)–(CH2CH2OMe)
CHMePr
CHEt2
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
MeO
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
H
H
H
H
H
H
H
H
H
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
H
1.0ꢅ0.2 (4)
1.4ꢅ0.1 (3)
2.1ꢅ0.9 (3)
8.0ꢅ4.7 (5)
19.4ꢅ10.7 (3)
8.5ꢅ1.3 (3)
20.8ꢅ10.6 (3)
57.2ꢅ25.3 (3)
74.1ꢅ46.1 (3)
0.7ꢅ0.2 (3)
2.0ꢅ0.1 (3)
2.6ꢅ1.0 (4)
3.7ꢅ1.1 (3)
5.0ꢅ1.1 (3)
18.2ꢅ3.3 (3)
69.0ꢅ42.0 (4)
78.4ꢅ13.0 (3)
204.0ꢅ23.4 (3)
1.2ꢅ0.4 (3)
1.4ꢅ0.3 (3)
11.9ꢅ2.7 (3)
1.3ꢅ0.3 (3)
2.7ꢅ0.8 (3)
25.9ꢅ5.2 (3)
4.1ꢅ1.1 (3)
7.6ꢅ0.8 (3)
CH(CH2CH2OMe)-(3-tetrahydrofuranyl)
CH(CH2CH2OMe)-(3-tetrahydrofuranyl)
4-Tetrahydropyranylc
Cyclopentylc
Cl
CHPr2
CHPr(CH2OMe)
CHMePr
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
MeO
EtO
MeO
MeO
MeO
MeO
CH(cyclobutyl)(CH2CH2OMe)
CHEt2
cyclopentyl
CH(CH2CH2OMe)–(3-tetrahydrofuranyl)
Cyclobutyl
4-Tetrahydropyranylc
CHPr2
CHPr(CH2OMe)
H
H
F
F
F
H
CHPr2
CHPr(CH2OMe)
CH(cyclobutyl)–(CH2CH2OMe)
CH(CH2CH2OMe)-(3-tetrahydrofuranyl)
CHPr2
a-Helical CRF9ꢁ41
aArithmetic meansand standard deviationsare reported for the Ki values; n isthe number of determinations.
bIndividual diastereomers.
cR1 and R2 taken together with the methine carbon form the cyclic substituents denoted in the table.
afforded a solution. Removal of solvent in vacuo pro-
vided 3-ethylpentanenitrile (7.4 g, 89% yield). 1H NMR
(CDCl3, 300 MHz) d 2.33 (d, 2H, J=6 Hz), 1.45–1.40
(m, 5H), 0.92 (t, 6H, J=7 Hz). MS (H2O–GC/MS) m/e
112 (100).
1.12 (t, 3H, J=7 Hz), 1.0–0.8 (m, 6H). MS (H2O–GC/
MS) m/e 167 (100).
A mixture of the above intermediate (7.0 g), hydrazine
hydrate (2.30 g, 2.23 mL, 46 mmol) and glacial acetic
acid (1 mL) in toluene washeated to reflux temperature
in a Dean–Stark apparatusand tsirred for 16 h. The
reaction mixture wascooled to ambient temperature
and solvent was removed in vacuo. EtOAc (100 mL)
was added to the residue and the resulting solution was
washed three times with a saturated NaHCO3 solution
(25 mL). The organic solution was dried over MgSO4,
filtered and concentrated in vacuo to provide 3-amino-
5-ethyl-4-(3-pentyl)pyrazole, an oil (6.7 g, 88% overall
A solution of di-isopropylamine (14.8 g, 20.5 mL, 147
mmol) in anhydrousTHF (40 mL) wascooled to
ꢁ78 ꢂC with stirring under a nitrogen atmosphere. A
solution of n-butyl lithium in hexanes(1.6 M, 87.5 mL,
140 mmol) wasadded dropwies over 15 min. The
resulting solution was stirred for an additional 30 min.
A solution of 3-ethylpentanenitrile (7.4 g, 67 mmol) in
THF (30 mL) wasadded dropwise over 15 min and then
the reaction mixture was stirred for 30 min. A solution
of ethyl propionate (6.8 g, 7.6 mL, 67 mmol) in THF (20
mL) wasadded dropwise; then the reaction mixture was
warmed with stirring to ambient temperature over 3 h.
The mixture waspoured onto water (200 mL) and the
pH wasadjusted to ꢄ4 by the slow addition of a con-
centrated HCl solution. Three extractions with ether
(100 mL), drying the combined organic layersover
MgSO4, filtration and removal of solvent in vacuo pro-
vided 4-cyano-5-ethyl-3-heptanone 9, an oil (9.53 g). 1H
NMR (CDCl3, 300 MHz) d 3.50 (d, 1H, J=4 Hz), 2.74
(q, 2H, J=7 Hz), 1.85–1.75 (m, 1H), 1.45–1.35 (m, 4H),
1
yield). H NMR (CDCl3, 300 MHz) d 2.53 (q, 2H, J=7
Hz), 1.70–1.50 (m, 5H), 1.20 (t, 3H, J=7 Hz), 0.83 (t,
6H, J=7 Hz). MS (NH3–CI) m/e 183 (12), 182 (100).
A mixture of 2,4-dichlorobenzamide (1.9 g, 10 mmol)
and N,N-dimethylformamide dimethyl acetal (3.5 g, 3.8
mL, 26 mmol) washeated at 120 ꢂC and stirred under a
nitrogen atmosphere for 2 h. After being cooled to
room temperature, the reaction mixture wascon-
centrated in vacuo to afford an oil. Medium pressure
chromatography on silica gel (EtOAc–hexanes: 1:3 to
1:1), followed by removal of solvent in vacuo afforded

P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
4097
N - (1 - (dimethylamino)ethylidene) - 2,4 - dichlorobenz-
1
wasadded to a solution of K 2CO3 (3.58 g, 25.9 mmol)
in H2O (20 mL) in a separatory funnel. The aqueous
amide, a solid (2.03 g, 78% yield). H NMR (CDCl3,
300 MHz) d 7.73 (d, 1H, J=8 Hz), 7.39 (d, 1H, J=2
Hz), 7.24 (dd, 1H, J=8,2 Hz), 3.16 (s, 3H), 3.13 (s, 3H),
2.39 (s, 3H).
layer wasextracted with CH Cl2 (4ꢃ6 mL). The com-
2
bined organic layerswere dried with Na SO4, and fil-
2
tered through a plug of cotton. The CH2Cl2 extract
containing the free base was transferred directly into a
round bottom flask containing of 3-amino-5-ethyl-4-(4-
heptyl)pyrazole 11 (1.77 g, 8.63 mmol). Acetonitrile (5
mL, anhydrous) was added followed by HOAc (0.54
mL, 9.49 mmol) and the mixture wasstirred overnight
at room temperature. The solid was collected by fil-
tration to give 2.07 g (78% yield) of 3-acetamidino-5-
ethyl-4-(4-heptyl)pyrazole acetic acid salt 18 asa white
solid, mp 154–156 ꢂC. 1H NMR 300 MHz (D2O) d 2.70–
2.61 (m, 3H), 2.40 and 2.17 (s, 3H, amidine rotomers),
1.87 (s, 3H), 1.64–1.48 (m, 4H), 1.26–1.14 (m, 7H), 0.86
(t, J=7.3 Hz, 6H). CI-HRMS m/e 251.2225 [(M+H)+,
free base]; calcd for C14H27N4: 251.2236].
Hydrogen sulfide was bubbled through glacial acetic
acid (20 mL) for approximately 5 min. N-(1-(Dimethyl-
amino)ethylidene)-2,4-dichlorobenzamide wasadded
portionwise over 5 min. Additional hydrogen sulfide
wasbubbled through the reaction mixture for approxi-
mately 10 min. Nitrogen wasthen bubbled through the
reaction mixture to purge the excess H2S. Dilution with
water (25 mL) caused a precipitate to form. The solid
wascollected by filtration, wahsed with copious
amountsof water and dried in vacuo. N-(Thioacetyl)-
2,4-dichlorobenzamide, a solid (1.75 g, 90% yield), was
used without further purification: 1H NMR (CDCl3,
300 MHz) d 9.9 (br s, 1H), 7.68 (d, 1H, J=8 Hz), 7.51
(d, 1H, J=2 Hz), 7.40 (dd, 1H, J=8 Hz, 2), 3.10 (s,
3H).
To a solution of K2CO3 (250 mg, 0.35 mmol) in H2O (3
mL) in a separatory funnel was added 3-acetamidino-5-
ethyl-4-(4-heptyl)pyrazole acetic acid salt 18 (175 mg,
0.565 mmol). The aqueouslayer wasextracted with
CH2Cl2 (4ꢃ15 mL). The combined organic layerswere
washed with brine, dried over Na2SO4, filtered and
concentrated to give the free base (105 mg, 0.419 mmol).
This intermediate (105 mg, 0.419 mmol) was dissolved
in dioxane (3 mL) and a solution of 2-chloro-4-meth-
oxybenzoyl chloride (112 mg, 0.545 mmol) in dioxane (1
mL) wasadded via cannula followed by the addition of
a catalytic amount of 4-dimethylaminopyridine (5 mg).
The mixture wasstirred at room temperature for 15 min
(turned cloudy then clear) and was subsequently heated
at reflux temperature for 15 h. The mixture wascooled
to room temperature and concentrated. The residue was
purified via preparative TLC (EtOAC–hexanes, 1:3) to
give 45 mg (27% yield) of the title compound 4s asa
yellow oil. 1H NMR (300 MHz, CDCl3) d 7.67 (d,
J=8.4 Hz, 1H), 7.07 (d, J=2.5 Hz, 1H), 6.96 (dd,
J=8.5, 2.2 Hz, 1H), 3.88 (s, 3H), 2.88–2.81 (m, 1H),
2.77 (q, J=7.7 Hz, 2H), 2.69 (s, 3H), 1.95–1.83 (m, 2H),
1.77–1.66 (m, 2H), 1.31–1.13 (m, 4H), 1.23 (t, J=7.4
Hz, 3H), 0.88 (t, J=7.3 Hz, 6H). Cl-HRMS m/e
401.2101 [(M+H)+; calcd for C22H30N4OCl: 401.2108].
A mixture of N-(thioacetyl)-2,4-dichlorobenzamide (200
mg, 0.81 mmol) and 3-amino-5-ethyl-4-(3-pentyl)pyr-
azole (146 mg, 0.81 mmol) in dioxane (1 mL) wasstirred
at reflux temperature for 16 h. After being cooled to
room temperature, the reaction mixture wascon-
centrated in vacuo. Preparative TLC (EtOAc–hexanes:
1:1) provided the title product (77.3 mg, 24% yield) mp
91–93 ꢂC. H NMR (CDCl3, 300 MHz) d 7.64 (d, 1H,
1
J=8 Hz), 7.57 (d, 1H, J=2 Hz), 7.44 (dd, 1H, J=8.2),
2.77 (q, 2H, J=8), 2.69 (s, 3H), 2.80–2.60 (m, 1H),
2.00–1.80 (m, 4H), 1.25 (t, 3H, J=8), 0.82 (t, 6H, J=7
Hz). CI-HRMS m/z calcd: 377.1294, found: 377.1303.
4-(2,4-Dichlorophenyl)-7-ethyl-2-methyl-8-(3-pentyl)-pyr-
azolo[1,5-a]-1,3,5-triazine (4e) (Method B). A mixture of
N-(thioacetyl)-2,4-dichlorobenzamide (400 mg, 1.6
mmol) and K2CO3 (445 mg, 3.22 mmol) in anhydrous
acetonitrile (20 mL) wasstirred at ambient temperature.
Iodomethane (458 mg, 0.2 mL, 3.22 mmol) wasadded
and the reaction mixture wasthen tsirred for 2.5 h.
Solvent wasremoved in vacuo and the residue waspar-
titioned between ether and water. The combined organic
layerswere dried over MgSO 4, filtered and concentrated
in vacuo to give N-(1-(methylthio)ethylidene)-2,4-
4-(2,4-Dichlorophenyl)-7-ethyl-8-(4-heptyl)-2-methyl-pyr-
azolo[1,5-a]-1,3,5-triazine (4a). The title compound was
prepared according to Method C to give a yellow solid,
1
dichlorobenzamide, an oil (406 mg). H NMR (CDCl3,
300 MHz) d 7.86 (d, 1H, J=8 Hz), 7.47 (d, 1H, J=2
Hz), 7.32 (dd, 1H, J=8, 2 Hz), 2.40 (s, 3H), 2.29 (s, 3H).
ꢂ
1
mp 76–77 C. H NMR (300 MHz, CDCl3) d 7.64 (d,
J=8.5 Hz, 1H), 7.57 (d, J=1.8 Hz, 1H), 7.43 (dd,
J=8.4, 2.2 Hz, 1H), 2.88–2.78 (m, 1H), 2.77 (q, J=7.4
Hz, 2H), 2.69 (s, 3H), 1.95–1.82 (m, 2H), 1.77–1.66 (m,
2H), 1.31–1.13 (m, 4H), 1.25 (t, J=7.7 Hz, 3H), 0.88 (t,
J=7.3 Hz, 6H). Cl-HRMS m/e 405.1614 [(M+H)+;
calcd for C21H27N4Cl2: 405.1613]. Anal. calcd for
C21H26N4Cl2: C, 62.22; H, 6.48; N, 13.82. Found: C,
62.27; H, 6.36; N, 13.49.
A mixture of N-(1-(methylthio)ethylidene)-2,4-dichloro-
benzamide (100 mg, 0.38 mmol) and 3-amino-5-ethyl-4-
(3-pentyl)pyrazole (69 mg, 0.38 mmol) in dioxane (1
mL) wastsirred at reflux temperature for 2 h. After
being cooled to room temperature, the reaction mixture
wasconcentrated in vacuo. Preparative TLC (EtOAc–
hexanes: 1:1) provided the title product (68 mg, 47%
yield), which wasidentical to the product obtained by
Method A.
4-(2,4-Dichlorophenyl)-7-ethyl-8-(1-methoxymethylbutyl)-
2-methyl-pyrazolo[1,5-a]-1,3,5-triazine (4b). The title
compound wasprepared according to Method C to give
4-(2-Chloro-4-methoxyphenyl)-7-ethyl-8-(4-heptyl)-2-
methyl - pyrazolo[1,5-a]-1,3,5-triazine (4s) (Method C).
Ethyl acetimidate hydrochloride (3.20 g, 25.9 mmol)
1
a yellow oil. H NMR (300 MHz, CDCl3) d 7.63 (d,
J=8.1 Hz, 1H), 7.57 (d, J=1.9 Hz, 1H), 7.43 (dd,

4098
P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
J=8.4, 1.9 Hz, 1H), 3.75 (ABq, JAB=9.2 Hz, Áu=15.1
Hz, 2H), 3.35 (s, 3H), 3.19–3.10 (m, 1H), 2.79 (q, J=7.4
Hz, 2H), 2.69 (s, 3H), 1.97–1.77 (m, 2H), 1.28-1.17 (m,
2H), 1.25 (t, J=7.3 Hz, 3H), 0.90 (t, J=7.3 Hz, 3H). Cl-
4-(2,4-Dichlorophenyl)-7-ethyl-2-methyl-8-(tetrahydro-4-
pyranyl) - pyrazolo[1,5 - a] - 1,3,5 - triazine (4h). The title
compound wasprepared according to Method B to give
1
a yellow oil. H NMR (300 MHz, CDCl3) d 7.60 (d,
HRMS m/e
407.1424 [(M+H)+;
calcd
for
J=8.4 Hz, 1H), 7.57 (d, J=1.8 Hz, 1H), 7.43 (dd,
J=8.4, 1.8 Hz, 1H), 4.15–4.05 (m, 1H), 3.60–3.53 (m,
2H), 3.06–2.98 (m, 2H), 2.82 (q, J=7.7 Hz, 2H), 2.70 (s,
3H), 2.47–2.37 (m, 2H), 1.71–1.61 (m, 2H), 1.26 (d,
J=7.5 Hz, 3H). CI-HRMS m/e 391.1097 [(M+H)+;
calcd for C19H21N4OCl2: 391.1092].
C20H25N4OCl2: 407.1405]. Anal. calcd for C20H24N4OCl2:
C, 58.97; H, 5.95; N, 13.75. Found: C, 59.11; H, 5.90;N,
13.61.
8-(1-Cyclobutyl-3-methoxypropyl)-4-(2,4-dichlorophenyl)-
7-ethyl-2-methyl-pyrazolo[1,5-a]-1,3,5-triazine (4c). The
title compound wasprepared according to Method B to
8-(Cyclopentyl)-4-(2,4-dichlorophenyl)-7-ethyl-2-methyl-
pyrazolo[1,5-a]-1,3,5-triazine (4i). The title compound
wasprepared according to Method B to give a yellow
amorphousoslid. 1H NMR (300 MHz, CDCl3) d 7.60
(d, J=8.0 Hz, 1H), 7.57 (d, J=1.9 Hz, 1H), 7.43 (dd,
J=8.4, 1.8 Hz, 1H), 3.20–2.10 (m, 1H), 2.80 (q, J=7.7
Hz, 2H), 2.69 (s, 3H), 1.95–1.85 (m, 6H), 1.75–1.65 (m,
2H), 1.25 (t, J=7.7 Hz, 3H).
give a yellow amorphousoslid.
1H NMR (300 MHz,
CDCl3) d 7.66 (d, J=8.1 Hz, 1H), 7.58 (d, J=2.2 Hz,
1H), 7.4 (dd, J=8.4, 1.8 Hz, 1H), 3.29–3.23 (m, 1H),
3.24 (s, 3H), 3.15–3.07 (m, 1H), 2.98–2.88 (m, 2H), 2.80
(q, J=7.7 Hz, 2H), 2.69 (s, 3H), 2.21–2.14 (m, 1H),
2.13–1.93 (m, 2H), 1.86–1.71 (m, 4H), 1.59–1.45 (m,
1H), 1.27 (t, J=7.7 Hz, 3H). CI-HRMS m/e 433.1583
[(M+H)+; calcd for C22H27N4OCl2: 433.1562]. Anal.
calcd for C22H26N4OCl2: C, 60.97; H, 6.06; N, 12.93.
Found: C, 60.84; H, 5.84; N, 12.66.
4-(2-Choro-4,5-dimethoxyphenyl)-7-ethyl-8-(4-heptyl)-2-
methyl-pyrazolo[1,5-a]-1,3,5-triazine (4j). The title com-
pound wasprepared according to Method C to give a
1
8-(2-Pentyl)-4-(2,4-dichlorophenyl)-7-ethyl-2-methyl-pyr-
azolo[1,5-a]-1,3,5-triazine (4d). The title compound was
prepared according to Method B to give a yellow
amorphousoslid, mp 80–82 ꢂC. 1H NMR (300 MHz,
CDCl3) d 7.62 (d, J=8.4 Hz, 1H), 7.57 (d, J=1.9 Hz,
1H), 7.43 (dd, J=8.4, 1.9 Hz, 1H), 3.08–2.88 (m, 1H),
2.78 (q, J=7.7 Hz, 2H), 2.70 (s, 3H), 1.95–1.85 (m, 1H),
1.76–1.71 (m, 1H), 1.40 (d, J=7.0 Hz, 3H), 1.25 (t,
J=7.7 Hz, 3H), 1.30–1.20 (m, 2H), 0.90 (t, J=7.3 Hz,
3H). CI-HRMS m/e 377.1326 [M+; calcd for
C19H23N4Cl2: 377.1300].
yellow oil. H NMR (300 MHz, CDCl3) d 7.23 (s, 1H),
7.01 (s, 1H), 3.95 (s, 3H), 3.91 (s, 3H), 2.88–2.83 (m,
1H), 2.79 (q, J=7.7 Hz, 2H), 2.70 (s, 3H), 1.96–1.83 (m,
2H), 1.77–1.66 (m, 2H), 1.32–1.13 (m, 4H), 1.27 (t,
J=7.3 Hz, 3H), 0.88 (t, J=7.3 Hz, 6H). Cl-HRMS m/e
431.2213 [(M+H)+; calcd for C23H32N4O2Cl:
431.2214].
4-(2-Chloro-4,5-dimethoxyphenyl)-7-ethyl-8-(1-methoxy-
methylbutyl)-2-methyl-pyrazolo[1,5-a]-1,3,5-triazine (4k).
The title compound wasprepared according to Method
1
C to give a yellow oil. H NMR (300 MHz, CDCl3) d
4-(2,4-Dichlorophenyl)-7-ethyl-8-[3-methoxy-1-(tetrahy-
drofuran-3-yl)-propyl]-2-methyl-pyrazolo[1,5-a]-1,3,5-tri-
azine (4f and 4g). The title compound wasprepared
according to Method B to give a mixture of diaster-
eomerswhich were esparated by HPLC (35% ethyl
acetate in hexanes, 21 mm silica column, 15 mL/min
flow rate).
7.22 (s, 1H), 7.01 (s, 1H), 3.95 (s, 3H), 3.90 (s, 3H), 3.76
(dd, J=7.3, 1.8 Hz, 2H), 3.36 (s, 3H), 3.21–3.10 (m,
1H), 2.81 (q, J=7.7 Hz, 2H), 2.70 (s, 3H), 1.97–1.77 (m,
2H), 1.30–1.18 (m, 2H), 1.28 (t, J=7.7 Hz, 3H), 0.90 (t,
J=7.3 Hz, 3H). Cl-HRMS m/e 433.2027 [(M+H)+;
calcd for C22H30N4O3Cl: 433.2006]. Anal. calcd for
C22H30N4O3Cl: C, 61.03; H, 6.75; N, 12.94. Found: C,
61.10; H, 6.75; N, 12.98.
Data for 4f: tR=24.4 min; yellow oil. 1H NMR
(300 MHz, CDCl3) d 7.67 (d, J=8.1 Hz, 1H), 7.58 (d,
J=2.2 Hz, 1H), 7.45 (dd, J=8.3, 2.0 Hz, 1H), 3.98–3.91
(m, 1H), 3.86–3.78 (m, 1H), 3.55 (t, J=8.0 Hz, 1H),
3.29–3.25 (m, 1H), 3.23 (s, 3H), 3.12–3.01 (m, 2H),
2.92–2.84 (m, 1H), 2.78 (q, J=7.5 Hz, 2H), 2.69 (s, 3H),
2.29–2.13 (m, 3H), 1.79–1.69 (m, 2H), 1.26 (t, J=7.7
Hz, 3H). Cl-HRMS m/e 449.1523 [(M+H)+; calcd for
C22H27N4O2Cl2: 449.1511].
4-(2-Chloro-4,5-dimethoxyphenyl)-7-ethyl-2-methyl-8-(1-
methylbutyl)-pyrazolo[1,5-a]-1,3,5-triazine (4l). The title
compound wasprepared according to Method C to give
an amorphousoslid.
1H NMR (300 MHz, CDCl3) d
7.21 (s, 1H), 7.01 (s, 1H), 3.95 (s, 3H), 3.90 (s, 3H),
3.04–2.96 (m, 1H), 2.80 (q, J=7.6 Hz, 2H), 2.70 (s, 3H),
1.94–1.67 (m, 2H), 1.41 (d, J=7.0 Hz, 3H), 1.41–1.12
(m, 2H), 1.27 (t, J=7.5 Hz, 3H), 0.91 (t, J=7.4 Hz, 3H).
Cl-HRMS m/e 403.1894 [(M+H)+; calcd for
C21H28N4O2Cl: 403.1901]. Anal. calcd for C21H27N4O2Cl:
C, 62.60; H, 6.75; N, 13.91. Found: C, 62.36; H, 6.89; N,
13.68.
Data for 4g: tR=27.8 min; yellow oil. 1H NMR
(300 MHz, CDCl3) d 7.67 (d, J=8.1 Hz, 1H), 7.58 (d,
J=1.8 Hz, 1H), 7.45 (dd, J=8.5, 2.2 Hz, 1H), 4.12 (t,
J=8.0 Hz, 1H), 3.83–3.78 (m, 1H), 3.70 (q, J=6.9 Hz,
1H), 3.58 (t, J=8.0 Hz, 1H), 3.25–3.20 (m, 1H), 3.22 (s,
3H), 3.08–3.00 (m, 2H), 2.94–2.86 (m, 1H), 2.79 (q,
J=7.7 Hz, 2H), 2.70 (s, 3H), 2.33–2.21 (m, 1H), 1.98–
1.87 (m, 1H), 1.75–1.65 (m, 1H), 1.50–1.40 (m, 1H), 1.27
(t, J=7.7 Hz, 3H). Cl-HRMS m/e 449.1529 [(M+H)+;
calcd for C22H27N4O2Cl2: 449.1511].
4-(2-Chloro-4,5-dimethoxyphenyl) - 8 - (1 - cyclobutyl - 3 -
methoxypropyl)-7-ethyl-2-methyl-pyrazolo[1,5-a]-1,3,5-
triazine (4m). The title compound wasprepared accord-
ing to Method B to give a yellow amorphoussolid. 1H
NMR (300 MHz, CDCl3) d 7.24 (s, 1H), 7.01 (s, 1H),
3.95 (s, 3H), 3.91 (s, 3H), 3.29–3.23 (m, 1H), 3.25 (s,

P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
4099
3H), 3.16–3.08 (m, 1H), 3.01–2.89 (m, 2H), 2.80 (q,
J=7.7 Hz, 2H), 2.69 (s, 3H), 2.22–2.15 (m, 1H), 2.13–
1.94 (m, 2H), 1.87–1.67 (m, 4H), 1.63–1.48 (m, 1H), 1.29
(t, J=7.3 Hz, 3H). Cl-HRMS m/e 459.2172 [(M+H)+;
calcd for C24H32N4O3Cl: 459.2163]. Anal. calcd for
C24H31N4O3Cl: C, 62.80; H, 6.82; N, 12.21. Found: C,
62.80; H, 6.73; N, 11.53.
4-(2-Chloro-4,5-dimethoxyphenyl)-7-ethyl-2-methyl-8-
(tetrahydro-4-pyranyl)-pyrazolo[1,5-a]-1,3,5-triazine (4r).
The title compound wasprepared according to Method
B to give a yellow amorphouosslid.
1H NMR
(300 MHz, CDCl3) d 7.19 (s, 1H), 7.00 (s, 1H), 4.15–4.07
(m, 1H), 3.95 (s, 3H), 3.90 (s, 3H), 3.61–3.53 (m, 2H),
3.07-2.97 (m, 1H), 2.84 (q, J=7.7 Hz, 2H), 2.71 (s, 3H),
2.45–2.41 (m, 2H), 1.75–1.63 (m, 2H), 1.28 (t, J=7.5
Hz, 3H). CI-HRMS m/e 417.1695 [(M+H)+; calcd for
C21H26N4O3Cl: 417.1693].
4-(2-Chloro-4,5-dimethoxyphenyl)-7-ethyl-2-methyl-8-(3-
pentyl)-pyrazolo[1,5-a]-1,3,5-triazine (4n). The title com-
pound wasprepared according to Method B to give a
solid, mp 103.5–105 ꢂC. H NMR (300 MHz, CDCl3) d
4-(2-Chloro-4-methoxyphenyl)-7-ethyl-8-(1-methoxyme-
thylbutyl)-2-methyl-pyrazolo[1,5-a]-1,3,5-triazine (4t).
The title compound wasprepared according to Method
1
7.23 (s, 1H), 7.01 (s, 1H), 3.95 (s, 3H), 3.91 (s, 3H), 2.79
(q, J=7.6 Hz, 2H), 2.70 (s, 3H), 2.71–2.60 (m, 1H),
2.00–1.77 (m, 4H), 1.27 (t, J=7.7 Hz, 3H), 0.83 (t,
J=7.4 Hz, 6H). Cl-HRMS m/e 403.1902 [(M+H)+;
calcd for C21H28N4O2Cl: 403.1901].
1
C to give a yellow oil. H NMR (300 MHz, CDCl3) d
7.66 (d, J=8.8 Hz, 1H), 7.07 (d, J=2.2 Hz, 1H), 6.96
(dd, J=8.8, 2.2 Hz, 1H), 3.88 (s, 3H), 3.75 (d, J=7.3
Hz, 2H), 3.35 (s, 3H), 3.19–3.09 (m, 1H), 2.79 (q, J=7.3
Hz, 2H), 2.68 (s, 3H), 1.96–1.77 (m, 2H), 1.29–1.17 (m,
2H), 1.26 (t, J=7.7 Hz, 3H), 0.89 (t, J=6.9 Hz, 3H). Cl-
HRMS m/e 402.1818 [M+; calcd for C21H27N4O2Cl:
402.1823]. Anal. calcd for C21H26N4O2Cl: C, 62.60; H,
6.75; N, 13.91. Found: C, 62.43; H, 6.81; N, 13.77.
4-(2-Chloro-4,5-dimethoxyphenyl)-8-(cyclopentyl)-7-ethyl
-2-methyl-pyrazolo[1,5-a]-1,3,5-triazine (4o). The title
compound wasprepared according to Method B to give
a yellow amorphoussolid. 1H NMR (300 MHz, CDCl3)
d 7.19 (s, 1H), 7.01 (s, 1H), 3.95 (s, 3H), 3.89 (s, 3H),
3.17 (m, 1H), 2.81 (q, J=7.7 Hz, 2H), 2.70 (s, 3H),
2.05–1.95 (m, 4H), 1.75–1.65 (m, 4H), 1.27 (t, J=7.5
Hz, 3H). CI-HRMS m/e 401.1746 [(M+H)+; calcd for
C21H26N4O2Cl: 401.1744].
4-(2-Chloro-4-ethoxyphenyl) - 7 - ethyl - 8 - (4 - heptyl) - 2 -
methyl-pyrazolo[1,5-a]-1,3,5-triazine (4u). The title com-
pound wasprepared according to Method C to give a
yellow solid, mp 86–87 ꢂC. 1H NMR (300 MHz, CDCl3)
d 7.65 (d, J=8.8 Hz, 1H), 7.06 (d, J=2.5 Hz, 1H), 6.94
(dd, J=8.8, 2.5 Hz, 1H), 4.10 (q, J=7.0 Hz, 2H), 2.89–
2.81 (m, 1H), 2.77 (q, J=7.7 Hz, 2H), 2.69 (s, 3H),
1.95–1.83 (m, 2H), 1.77–1.72 (m, 2H), 1.45 (t, J=6.9
Hz, 3H), 1.31–1.12 (m, 4H), 1.26 (t, J=7.7 Hz, 3H),
0.88 (t, J=7.4 Hz, 6H). Cl-HRMS m/e 415.2277
[(M+H)+; calcd for C23H32N4OCl: 415.2256]. Anal.
calcd for C23H31N4OCl: C, 66.57; H, 7.54; N, 13.50.
Found: C, 66.73; H, 7.66; N, 13.44.
4-(2-Chloro-4,5-dimethoxyphenyl)-7-ethyl-8-[3-methoxy-
1-(tetrahydrofuran-3-yl)-propyl]-2-methyl-pyrazolo[1,5-
a]-1,3,5-triazine (4p). The title compound wasprepared
according to Method B asa mixture of diatesr-
eomerswhich wasoislated by HPLC (50% ethyl
acetate in hexanes, 21 mm silica column, 15 mL/min
flow rate).
Data for 4p: tR=29.7 min; 1H NMR (300 MHz, CDCl3)
d 7.25 (s, 1H), 7.02 (s, 1H), 3.95 (s, 3H), 3.52 (s, 3H),
3.82 (q, J=6.9 Hz, 1H), 3.56 (t, J=8.0 Hz, 1H), 3.46–
3.42 (m, 1H), 3.33–3.24 (m, 1H), 3.24 (s, 3H), 3.10–3.03
(m, 2H), 2.93–2.84 (m, 1H), 2.79 (q, J=7.7 Hz, 2H),
2.70 (s, 3H), 2.27–2.10 (m, 4H), 1.73 (dd, J=12.1, 8.4
Hz, 1H), 1.28 (t, J=7.7 Hz, 3H). tR=31.2 min; 1H
NMR (300 MHz, CDCl3) d 7.25 (s, 1H), 7.02 (s, 1H),
4.12 (t, J=8.0 Hz, 1H), 3.96 (s, 3H), 3.92 (s, 3H), 3.83–
3.80 (m, 1H), 3.70 (q, J=8.1 Hz, 1H), 3.58–3.55 (m,
1H), 3.22 (s, 3H), 3.09–3.03 (m, 2H), 2.94–2.86 (m, 1H),
2.81 (q, J=7.7 Hz, 2H), 2.70 (s, 3H), 2.30–2.22 (m, 1H),
1.96–1.88 (m, 1H), 1.78–1.69 (m, 2H), 1.49–1.42 (m,
1H), 1.30–1.25 (m, 3H). Cl-HRMS m/e 475.2093
[(M+H)+; calcd for C24H32N4O4Cl: 475.2112]. Anal.
calcd for C24H31N4O4Cl: C, 60.69; H, 6.59; N, 11.80.
Found: C, 60.50; H, 6.33; N, 11.55.
4-(2-Chloro-5-fluoro - 4 - methoxyphenyl) - 7 - ethyl - 8 - (1 -
methoxymethylbutyl)-2-methyl-pyrazolo[1,5-a]-1,3,5-tria-
zine (4v). The title compound wasprepared according
to Method C to give a yellow solid, mp 122–123 ꢂC.
1H NMR (300 MHz, CDCl3) d 7.49 (d, J=11.0 Hz,
1H), 7.11 (d, J=7.3 Hz, 1H), 3.96 (s, 3H), 3.75 (d,
J=7.4 Hz, 2H), 3.35 (s, 3H), 3.19–3.09 (m, 1H),
2.80 (q, J=7.7 Hz, 2H), 2.69 (s, 3H), 1.97–1.77 (m, 2H),
1.30–1.17 (m, 2H), 1.27 (t, J=7.7 Hz, 3H), 0.90 (t,
J=7.4 Hz, 3H). Cl-HRMS m/e 421.1798 [(M+H)+;
calcd for C21H27N4O2ClF: 412.1806]. Anal. calcd for
C21H26N4O2ClF: C, 59.92; H, 6.24; N, 13.31. Found: C,
59.84; H, 6.20; N, 13.28.
4-(2-Chloro-5-fluoro-4-methoxyphenyl)-8-(1-cyclobutyl-
3-methoxypropyl)-7-ethyl-2-methyl-pyrazolo[1,5-a]-1,3,5-
triazine (4w). The title compound wasprepared accord-
ing to Method B to give a yellow amorphoussolid. 1H
NMR (300 MHz, CDCl3) d 7.52 (d, J=10.6 Hz, 1H),
7.12 (d, J=7.3 Hz, 1H), 3.97 (s, 3H), 3.29–3.23 (m, 1H),
3.25 (s, 3H), 3.15–3.06 (m, 1H), 3.00–2.89 (m, 2H), 2.82
(q, J=7.7 Hz, 2H), 2.69 (s, 3H), 2.22–2.15 (m, 1H),
2.14–1.92 (m, 2H), 1.60–1.46 (m, 1H), 1.86-1.65 (m,
4H), 1.29 (t, J=7.3 Hz, 3H). Cl-HRMS m/e 447.1957
[(M+H)+; calcd for C23H29N4O2ClF: 447.1963]. Anal.
4-(2-Chloro-4,5-dimethoxyphenyl)-8-(cyclobutyl)-7-ethyl-
2-methyl-pyrazolo[1,5-a]-1,3,5-triazine (4q). The title
compound wasprepared according to Method B to give
a yellow amorphoussolid. 1H NMR (300 MHz, CDCl3)
d 7.17 (s, 1H), 7.00 (s, 1H), 3.95 (s, 3H), 3.89 (s, 3H),
3.71–3.61 (m, 1H), 2.80 (q, J=7.7 Hz, 2H), 2.72 (s, 3H),
2.75–2.65 (m, 2H), 2.35–2.25 (m, 2H), 2.05–1.95 (m,
2H), 1.25 (t, J=7.5 Hz, 3H). CI-HRMS m/e 387.1600
[(M+H)+; calcd for C20H24N4O2Cl: 387.1588].

4100
P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
calcd for C23H28N4O2ClF: C, 61.81; H, 6.31; N, 12.54.
Found: C, 61.55; H, 6.12; N, 11.96.
(200 mL). The mixture was transferred to a separatory
funnel and the layerswere separated. The aqueouslayer
wasextracted with ether (3 ꢃ150 mL). The organic lay-
erswere combined, wahsed with brine (50 mL), dried
over MgSO4, filtered and concentrated to afford 1-
methoxypentan-2-one 7 (6.45 g, 93% yield) asa color-
less oil. 1H NMR (CDCl3, 300 MHz) d 4.02 (s, 2H), 3.42
(s, 3H), 2.42 (t, J=7.3 Hz, 2H), 1.63 (sextet, J=7.4 Hz,
2H), 0.94 (t, J=7.3 Hz, 3H). GC/MS m/e 116.0 [M+;
calcd for C6H12O2: 134.1].
4-(2-Chloro-5-fluoro - 4 - methoxyphenyl) - 7 - ethyl - 8 - [3 -
methoxy-1-(tetrahydrofuran-3-yl)-propyl]-2-methyl-pyra-
zolo[1,5-a]-1,3,5-triazine (4x). The title compound was
prepared according to Method B to give a mixture of
diasteriomers which were separated by HPLC (40%
ethyl acetate in hexanes, 21 mm silica column, 15 mL/
min flow rate, tR=19.9 min and 22.2 min).
Data for 4x: tR=19.9 min; yellow oil; 1H NMR
(300 MHz, CDCl3) d 7.52 (d, J=10.9 Hz, 1H), 7.12 (d,
J=7.4 Hz, 1H), 3.97 (s, 3H), 3.95–3.86 (m, 1H), 3.84–
3.78 (m, 1H), 3.56 (t, J=7.9 Hz, 1H), 3.29–3.25 (m, 1H),
3.23 (s, 3H), 3.12–3.01 (m, 2H), 2.92–2.84 (m, 1H), 2.79
(q, J=7.5 Hz, 2H), 2.69 (s, 3H), 2.29–2.11 (m, 3H),
1.79–1.66 (m, 2H), 1.28 (t, J=7.6 Hz, 3H). Cl-HRMS
m/e 463.1937 [(M+H)+; calcd for C23H29N4O3ClF:
463.1912].
NaH (3.37 g, 83.4 mmol, 60% in mineral oil) wasadded
to a three-necked round-bottom flask equipped with an
addition funnel. THF wasadded to the flaks and the
suspension was cooled to 0 ꢂC. Diethyl cyanomethyl-
phosphonate (15.8 mL, 89 mmol) was added dropwise
while maintaining the temperature between 0 and 5 ꢂC.
After the addition wascomplete (reaction mixture
turned colorless), the mixture was stirred at 0 ꢂC for 1 h.
1-Methoxypentan-2-one (6.45 g, 55.6 mmol) in THF
(100 mL) wasadded slowly via an addition funnel and
the reaction mixture washeated at reflux for 3 h. The
reaction mixture wascooled to room temperature and
was poured into a separatory funnel containing satu-
rated NH4Cl (150 mL). The aqueouslayer wasextracted
with EtOAc (3ꢃ150 mL). The combined organic layers
were washed with brine (100 mL), dried over MgSO4,
filtered and concentrated. The residue was purified by
column chromatography on silica gel (10% EtOAc in
hexanes) to furnish 3-methoxymethyl-hex-2-enenitrile 8
(7.10 g, 92% yield) asa mixture of E and Z isomersasa
colorless oil. 1H NMR (CDCl3, 300 MHz) d 5.48 (t,
J=2.0 Hz, 1H, major), 5.26 (s, 1H, minor), 4.20 (s, 2H,
minor), 3.96 (d, J=1.8 Hz, 2H, major), 3.39 (s, 3H,
major), 3.37 (s, 3H, minor), 2.35 (t, J=7.7 Hz, 2H,
major), 2.25 (t, J=7.7 Hz, 2H, minor), 1.59–1.45 (m, 2H),
0.98 (t, J=7.4 Hz, major), 0.95 (t, J=7.4 Hz, 3H, minor).
GC/MS m/e 139.0 [M+; calcd for C8H13NO: 139.1].
4-(2,4-dimethoxyphenyl)-7-ethyl-8-(4-heptyl)-2-methyl-
pyrazolo[1,5-a]-1,3,5-triazine (4y). The title compound
wasprepared according to Method C to give a yellow
solid, mp=87–88 ꢂC. 1H NMR (300 MHz, CDCl3) d
7.62 (d, J=8.4 Hz, 1H), 6.63 (dd, J=8.4, 2.2 Hz, 1H),
6.60 (d, J=2.6 Hz, 1H), 3.88 (s, 3H), 3.80 (s, 3H), 2.87–
2.79 (m, 1H), 2.76 (q, J=7.7 Hz, 2H), 2.67 (s, 3H),
1.95–1.82 (m, 2H), 1.76–1.65 (m, 2H), 1.31–1.13 (m,
4H), 1.25 (t, J=7.7 Hz, 3H), 0.87 (t, J=7.3 Hz, 6H). Cl-
HRMS m/e 397.2608 [(M+H)+; calcd for C23H33N4O2:
397.2604]. Anal. calcd for C23H32N4O2: C, 69.67; H,
8.13; N, 14.13. Found: C, 69.47; H, 8.33; N, 13.96.
5-Ethyl-4-(1-methoxymethylbutyl)-2H-pyrazol-3-ylamine
(11). A solution of methoxyacetic acid (14.0 g, 155
mmol) in CH2Cl2 (400 mL) wastreated with triethyl-
amine (40 mL) and N,O-dimethoxyhydroxylamine
(18.20 g, 187 mmol). After stirring 5 min, the solution
ꢂ
wascooled to 0 C. EDC (32.80 g, 171 mmol) wasadded
A solution of 3-methoxymethyl-hex-2-enenitrile (7.0 g,
50.3 mmol) in methanol (310 mL) wastreated with 10%
Pd/C asa lsurry in cold ( ꢁ78 ꢂC) isopropanol with a
stream of nitrogen passing over the reaction mixture.
and the reaction mixture wastsirred overnight while
allowing the reaction mixture to warm to room tem-
perature. The mixture wasdiluted with CH 2Cl2 (400
mL) and wastranfserred to a esparatory funnel. The
organic layer waswahsed with 1 N HCl (2 ꢃ200 mL),
saturated NaHCO3 (2ꢃ200 mL), water (1ꢃ200 mL),
brine (200 mL), dried over MgSO4, filtered and con-
centrated to afford 2,N-dimethoxy-N-methylacetamide
The reaction mixture wasevacuated and filled with N
2
(3ꢃ) and then H2 (3ꢃ) and wastsirred overnight at
room temperature. The reaction mixture wasplaced
under a N2 atmosphere and was filtered through a pad
of Celite. The filtrate wasconcentrated to give 3-meth-
oxymethyl-hexanenitrile 9 (4.85 g, 68% yield) asa col-
6 (12.85 g, 62% yield) asa colorlessoil.
1H NMR
1
(CDCl3, 300 MHz) d 4.23 (s, 2H), 3.70 (s, 3H), 3.47 (s,
3H), 3.20 (s, 3H). MS (NH3-CI) m/e 134.1 [(M+H)+;
calcd for C5H12NO3: 134.1].
orless oil which was used directly in the next step. H
NMR (CDCl3, 300 MHz) d 3.42 (1/2 ABX, JAB=9.6
Hz, JAX=4.4 Hz, 1H), 3.35 (s, 3H), 3.27 (1/2 ABX
JBA=9.5 Hz, JBX=7.7 Hz, 1H), 2.45 (d, J=5.9 Hz,
2H), 2.03–1.93 (m, 1H), 1.43–1.33 (m, 4H), 0.93 (t,
J=6.9 Hz, 3H).
Propylmagnesium chloride (36.0 mL, 72.1 mmol, 2 M)
was added dropwise to a solution of 2,N-dimethoxy-N-
methylacetamide (8.0 g, 60.08 mmol) in diethyl ether
(440 mL) while maintaining the temperature below 8 ꢂC.
After the addition wascomplete, the reaction mixture
wastsirred at 0 ꢂC for 30 min. The cooling bath was
removed and the reaction mixture wastsirred for an
additional 45 min while allowing it to warm to room
temperature. The reaction mixture wasthen cooled to
0 ꢂC and wasquenched by the slow addition of 1 N HCl
To a dried 200 mL round bottom flask containing a
solution of THF (36 mL) and i-Pr2NH (10.5 mL, 75.2
mmol) at ꢁ78 ꢂC wasadded dropwise n-BuLi (28.7 mL,
71.8 mmol, 2.5 M in hexanes). The mixture was warmed
to 0 ꢂC and stirred at 0 ꢂC for 30 min then cooled to
ꢁ78 ꢂC. 3-Methoxymethylhexanenitrile (4.85 g, 34.2
mmol) in THF (10 mL) wasadded dropwise via cannula.

P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
4101
The mixture wasstirred at ꢁ78 ꢂC for 30 min then ethyl
propionate (3.92 mL, 34.2 mmol) in THF (3 mL) was
added dropwise via cannula. The cooling bath was
removed and the reaction mixture wasallowed to warm
to room temperature and wasstirred for 4 h. The reac-
tion mixture wastranfserred to a esparatory funnel
containing H2O (100 mL). The layerswere esparated
silica gel (10% EtOAc in hexanes) to furnish 3,3-dicy-
clopropylacrylonitrile 8 (6.83 g, 95% yield) asa color-
less oil. H NMR (CDCl3, 300 MHz) d 4.79 (d, J=0.70
Hz, 1H), 2.24–2.15 (m, 1H), 1.03–0.94 (m, 5H), 0.85–
0.79 (m, 2H), 0.58–0.52 (m, 2H). GC/MS m/e 134.0
[M+; calcd for C9H12N: 134.0].
1
and the organic layer wasextracted with H O (4ꢃ50
A solution of 3,3-dicyclopropylacrylonitrile (4.90 g, 36.8
mmol) in methanol (230 mL) wastreated with 10% Pd/
C asa slurry in cold ( ꢁ78 ꢂC) isopropanol with a stream
of nitrogen passing over the reaction mixture. The
2
mL). The combined aqueouslayerswere placed in an ice
bath and acidified to pH 4 with concentrated HCl. The
aqueouslayer wastranfserred to a esparatory funnel
and wasextracted with ether (4 ꢃ10 mL). The combined
organic layerswere wahsed with brine, dried over
MgSO4, filtered and concentrated to afford 3-methoxy-
methyl-2-propionylhexanenitrile 10 (5.85 g, 87% yield)
as a colorless oil which was used directly in the next step.
1H NMR (CDCl3, 300 MHz) d 4.21–4.15 (m, 1H, major),
3.84 (d, J=4.4 Hz, 1H, minor), 3.52–3.20 (m, 2H), 3.33
(s, 3H, minor), 3.25 (s, 3H, major), 2.88–2.44 (m, 3H),
1.44–1.18 (m, 4H), 1.12 (t, J=7.3 Hz, 3H, minor), 1.09 (t,
J=7.3 Hz, 3H, major), 0.96–0.88 (m, 3H). GC/MS m/e
197.0 [M+; calcd for C11H19NO2: 197.1].
reaction mixture wasevacuated and filled with N (3ꢃ)
2
and then H2 (3ꢃ) and wastsirred overnight at room
temperature. The reaction mixture wasplaced under a
N2 atmosphere and was filtered through a pad of Celite.
The filtrate wasconcentrated to give 3-propylhexaneni-
trile 9 (4.23 g, 85% yield) asa colorlesoil which was
used directly in the next step. 1H NMR (CDCl3,
300 MHz) d 2.32 (d, J=5.9 Hz, 2H), 1.74–1.68 (m,1H),
1.44–1.23 (m, 8H), 0.94–0.87 (m, 6H).
1-Cyclobutyl-3-methoxypropan-1-one. To a solution of
cyclobutanecarboxylic acid N-methoxy-N-methyl amide
(10.02 g, 70.0 mmol) in THF (200 mL) at ꢁ78 ꢂC was
added vinylmagnesium bromide (73.5 mL, 73.5 mmol,
1 M in THF) dropwise. The reaction mixture was stirred
at ꢁ78 ꢂC for 45 min and was subsequently treated with
anhydrousmethanol (130 mL) followed by concd
H2SO4 (10.1 mL, 189 mmol). The cooling bath was
removed and the reaction mixture wastsirred at room
temperature overnight. Saturated NaHCO3 (170 mL)
wasadded lsowly and the precipitate wasremoved by
filtration through a pad of Celite. The organic solvents
were removed under reduced pressure. The aqueous
Acetic acid (6.52 mL) wasadded to a oslution of 3-
methoxymethyl-2-propionylhexanenitrile (5.61 g, 28.7
.
mmol) and NH2NH2 H2O (3.17 mL, 65.3 mmol) in tol-
uene (170 mL) in a flask equipped with a Dean–Stark
trap. The solution was heated at reflux overnight. The
mixture wascooled to room temperature and con-
centrated. The residue was dissolved in 1 N HCl (100
mL) and waswashed with ether–hexane (1:1, 2 ꢃ80 mL)
then brought to pH 11 with concd NH4OH (some cool-
ing wasrequired). The oslution wasextracted with
EtOAc (3ꢃ80 mL) and the combined organic layerswere
washed with brine (50 mL), dried over MgSO4, filtered
and concentrated to furnish 5-ethyl-4-(1-methoxy-
methylbutyl)-2H-pyrazol-3-ylamine 11 (4.30 g, 72%
portion wasdiluted with additional saturated NaHCO
3
(200 mL) and wasextracted with CH Cl2 (3ꢃ200 mL).
2
The combined organic layerswere wahsed with brine,
dried over Na2SO4, filtered and concentrated. The resi-
due waspurified by column chromatography on islica
gel (20% ether in hexanes) to afford 1-cyclobutyl-3-
methoxypropan-1-one 7 (3.22 g, 32% yield) asa color-
1
yield) asa tan oil. H NMR (CDCl3, 300 MHz) d 3.56 (1/
2 ABX, JAB=8.8 Hz, JAX=4.4 Hz, 1H), 3.49 (1/2 ABX,
JBA=8.8 Hz, JBX=4.4 Hz, 1H), 3.34 (s, 3H), 3.0 (br s,
2H), 2.67–2.58 (m, 1H), 2.53 (q, J=7.3 Hz, 2H), 1.90
(br s, 1H), 1.75–1.60 (m,2H), 1.31–1.17 (m, 2H), 1.19 (t,
J=7.7 Hz, 3H), 0.89 (t, J=7.3 Hz, 3H). MS (NH3-CI)
m/e 212.2 [(M+H)+; calcd for C11H22N3O: 212.2].
1
less oil. H NMR (CDCl3, 300 MHz) d 3.64 (t, J=6.2
Hz, 2H), 3.33 (s, 3H), 3.28 (t, J=7.7 Hz, 1H), 2.61 (t,
J=6.2 Hz, 2H), 2.28–2.10 (m, 4H), 2.08–1.73 (m, 2H).
3-Propylhexanenitrile. NaH (3.26 g, 81.5 mmol, 60% in
mineral oil) wasadded to a three-necked round-bottom
flask equipped with an addition funnel. THF was added
to the flask and the suspension was cooled to 0 ꢂC.
Diethyl cyanomethylphosphonate (14.2 mL, 87.3 mmol)
wasadded dropwise while maintaining the temperature
between 0 and 5 ꢂC. After the addition wascomplete
(reaction mixture turned colorless), the mixture was
stirred at 0 ꢂC for 1 h. 1-Dicyclopropylketone (6.14 g,
54.5 mmol) in THF (120 mL) wasadded slowly via an
addition funnel and the reaction mixture washeated at
reflux for 2.5 h. The reaction mixture wascooled to
room temperature and waspoured into a esparatory
funnel containing saturated NH4Cl (150 mL). The aqu-
eouslayer wasextracted with EtOAc (3 ꢃ150 mL). The
combined organic layerswere wahsed with brine (100
mL), dried over MgSO4, filtered and concentrated. The
residue was purified by column chromatography on
Tetrahydrofuran-3-carboxylic acid. A solution of 3-
furoic acid (2.0 g, 17.8 mmol) in 3% NaOH solution (25
mL) was treated with Raney–Ni (4.0 g, 50% dispersion
in H2O) and subjected to hydrogenation at room tem-
perature for 78 h at 50 psi. After removal of the catalyst,
the solution was acidified with 1 N HCl and was
extracted with ether (4ꢃ50 mL). The combined organic
extractswere dried over MgSO 4, filtered and con-
centrated to provide tetrahydrofuran-3-carboxylic acid
1
5 (1.2 g, 58% yield) a colorless oil. H NMR (CDCl3,
300 MHz) d 4.00 (d, J=6.9 Hz, 2H), 3.99–3.80 (m, 2H),
3.22–3.09 (m, 1H), 2.31–2.11 (m, 2H).
Acknowledgements
We thank Susan Keim, Anne Marshall and Carol Krause
for expert technical assistance in the binding assay.

4102
P. J. Gilligan et al. / Bioorg. Med. Chem. 11 (2003) 4093–4102
P. J.; Wilde, R. G.; Cocuzza, A.; Hobbs, F. W.; Cheeseman,
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