Design, synthesis, and discovery of a novel CCR1 antagonist

Article abstract of DOI:10.1021/jm0004244

The CC chemokines may play an important role in the pathogenesis of chronic inflammatory diseases including rheumatoid arthritis, and their effects are thought to be mediated through CCR1 receptors. Several nonpeptide CCR1 receptor antagonists that showed

Full text of DOI:10.1021/jm0004244

J . Med. Chem. 2001, 44, 1429-1435
1429
Design , Syn th esis, a n d Discover y of a Novel CCR1 An ta gon ist
Akira Naya,* Yufu Sagara, Kenji Ohwaki, Toshihiko Saeki, Daisuke Ichikawa, Yoshikazu Iwasawa,
Kazuhito Noguchi, and Norikazu Ohtake*
Banyu Tsukuba Research Institute in collaboration with Merck Research Laboratories,
Okubo-3, Tsukuba 300-2611, Ibaraki, J apan
Received October 2, 2000
The CC chemokines may play an important role in the pathogenesis of chronic inflammatory
diseases including rheumatoid arthritis, and their effects are thought to be mediated through
CCR1 receptors. Several nonpeptide CCR1 receptor antagonists that showed high affinity for
human CCR1 receptors have been identified; however, their effectiveness in animal models of
inflammatory diseases has been scarcely demonstrated, probably due to species selectivity of
the antagonists. To elucidate the pathophysiological role of CCR1 receptors in murine models
of disease, we looked for a potent antagonist for both murine and human CCR1 receptors.
Screening of our chemical collection for inhibition of 125I-MIP-1R binding to human CCR1
receptors transfected in CHO cells led to the identification of xanthene-9-carboxamide 1a as
the lead compound. Derivatization of 1a by quaternarizing the piperidine nitrogen with various
alkyl groups and by installing substituents into the xanthene moiety dramatically improved
the inhibitory activity against both human and murine CCR1 receptors. As a result, 2q -1
showing IC50 values of 0.9 and 5.8 nM for human and murine CCR1 receptors, respectively,
was discovered. This compound is the first murine CCR1 receptor antagonist and may be a
useful tool for clarifying the role of CCR1 receptors in murine models of disease.
In tr od u ction
been identified by pharmaceutical companies such as
Berlex8 and Takeda.9 Recently, species selectivity of the
CCR1 antagonist was reported, especially between
humans and mice.10 This species selectivity may com-
plicate the demonstration of efficacy of a CCR1 antago-
nist in animal models of disease. Therefore, we decided
to seek a potent antagonist for both mouse and human
CCR1 receptors, to determine the pathophysiological
role(s) of CCR1 receptors in murine models of disease.
Chemokines, constituting a large family of chemo-
tactic cytokines, are thought to be proinflammatory
molecules implicated in the recruitment and activation
of leukocytes in various diseases such as rheumatoid
arthritis, multiple sclerosis, and asthma.1,2 Chemokines
are largely classified into two subfamilies, CXC or
R-chemokines and CC or â-chemokines, based on the
position of the first cysteine pair of their four conserved
cysteines.3 The specific effects of chemokines are medi-
ated by their receptor which belongs to a family of the
seven transmembrane G-protein-coupled receptors
(GPCR). A total of 18 chemokine receptors including
CCR1-11, CXCR1-5, XCR1, and CX3CR1 receptors are
known to date.
Among the chemokines, MIP-1R (macrophage inflam-
matory protein-1R) and RANTES (regulated on activa-
tion normal T-cell expressed and secreted), known as
ligands for CCR1 receptors, may play an important role
in chronic inflammatory diseases such as rheumatoid
arthritis4 and multiple sclerosis.5 For example, it was
reported that treatment of antibodies to RANTES
resulted in a great reduction in clinical scores compared
to the scores of untreated animals in a rat adjuvant-
induced arthritis model.6 Furthermore, RANTES pro-
tein and mRNA were reported to be upregulated in the
synovial fibroblasts of patients with rheumatoid arthri-
tis.7 Taken together, these findings suggested that
selective antagonists for CCR1 receptors may be an
attractive therapeutic target for chronic inflammatory
diseases.
A screening of our chemical collection of compounds
for percent inhibition at 1 µM for 125I-MIP-1R binding
to human CCR1 receptors transfected in CHO led to the
discovery of xanthenecarboxamide 1a with an IC50 value
of 510 nM as a lead compound. In this paper, we
describe the design, synthesis, and structure-activity
relationship (SAR) of xanthenecarboxamide derivatives
on the binding affinity for mouse and human CCR1
receptors, based on the structure of the lead compound
1a .
Resu lts a n d Discu ssion
Ch em istr y. General methods for the synthesis of
compounds 1a -n and 2a -r are outlined in Scheme 1.
Acylation of the 4-aminopiperidine derivative 3 with an
acid using the WSC-HOBT method, followed by depro-
tection of the Boc group under acidic conditions and
Several nonpeptide CCR1 receptor antagonists that
showed high affinity for human CCR1 receptors have
* To whom correspondence should be addressed. Tel: 81-298-77-
2000. Fax: 81-298-77-2029. E-mail: nayaak@banyu.co.jp.
10.1021/jm0004244 CCC: $20.00 © 2001 American Chemical Society
Published on Web 03/31/2001

1430 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Naya et al.
Sch em e 1a
a
Reagents: Method A - (1) R1CO2H, WSC-HCl, HOBt, Et3N; (2) HCl-MeOH; (3) R2CHO, NaBH(OAc)3; Method B - R1CO2H, WSC-
HCl, HOBt, Et3N; Method C - R1CO2H, CDI; Method D - R3X.
Sch em e 2a
by substituting the n-hexyl group on the piperidine
nitrogen with cycloalkyl or arylmethyl groups. Replace-
ment with a cyclohexyl (1b), cyclooctyl (1c), or cyclode-
canyl (1d ) group resulted in improvement in the binding
affinity for human CCR1 receptors, especially in the
case of 1c, which showed approximately 3-fold higher
binding affinity compared with 1a . By contrast, replace-
ment with aromatic groups, such as benzyl (1e) and
2-naphthylmethyl (1f) led to a substantial loss of affin-
ity. Unfortunately, binding affinity of the compounds
for mouse CCR1 receptors was not detected, indicating
that there is high species selectivity of this xanthen-
ecarboxamide class of compounds between human and
mouse CCR1 receptors. Next, the cyclooctyl moiety on
the piperidinyl side chain of 1c being fixed, replacement
of the xanthene moiety was performed to explore an
alternative pharmacophore. When the xanthen-9-yl
moiety of 1c was replaced with an anthracen-9-yl one,
the resulting compound 1g lost potency. Substitution
of this moiety with a diphenylmethyl (1h ) or diphenyl-
methyl(hydroxy)methyl (1i) group resulted in an ap-
proximately 10-fold reduction of binding affinity for
human CCR1 receptors. Interestingly, a 2,7-dichrolo-
(1j) or 2,7-dibromoxanthen-9-yl (1k ) group significantly
reduced potency. These results indicated that the xan-
then-9-yl moiety was optimal as the acid segment of 1c.
a
Reagents: (1) RCHO, NaBH(OAc)3; (2) HCl-MeOH.
Sch em e 3a
a
Reagents: (a) (1) p-TsNHNH2, (2) n-BuLi, DMF; (b) (1) n-BuLi,
(EtO)2POCH2NC, (2) HCl.
subsequent reductive N-alkylation with an appropriate
aldehyde, gave compound 1 in a 60-70% yield (method
A). Alternatively, compound 1 was also synthesized from
amine 4 that was commercially available or easily
prepared as shown in Scheme 2 (method B or C). Most
of the aldehydes used for the preparation of compound
1 were commercially available. Cycloalkylcarboxalde-
hydes such as 1-cyclooctenyl- and cyclodecanylcarbox-
aldehyde were prepared as shown in Scheme 3. Cyclo-
octanone tosylhydrazone was treated with n-BuLi and
subsequently reacted with DMF to afford 8 in 53% yield.
Cyclodecanylcarboxaldehyde was obtained from cyclo-
decanone by reaction with lithium diethyl (isocyano-
methyl)phosphonate and subsequent acidic hydrolysis.
Compound 1 was quaternarized with an appropriate
alkyl halide to provide the quaternary ammonium
derivative 2 (method D) as a mixture of two isomers (cis
and trans) attributed to the 4-substituted piperidinium
structure in a ratio of ∼2:1, which was evaluated in the
binding assay without separation. Compound 2q, the
most potent compound, was separated by silica gel
column chromatography to give a major isomer (2q-1,
59%) and a minor isomer (2q-2, 32%).
Comparison of the binding affinity of 1c with that of
the Berlex compound in our binding assay system
revealed that the Berlex compound was more active
than 1c and that both compounds still possessed species
selectivity between humans and mice.
We hypothesized that the piperidine nitrogen in this
series of compounds was recognized as a cation binding
site that was close to the hydrophobic site recognizing
the cycloalkyl moiety in the CCR1 receptor antagonist
binding pocket.8,11 Therefore, a quaternary ammonium
group could be used to replace the tertiary piperidine
nitrogen. Following up this hypothesis, the quaternary
ammonium compound 2a was prepared and evaluated
in the binding assay. Interestingly, 2a showed greatly
enhanced binding affinity not only to human CCR1 but
also to mouse CCR1 receptors, with IC50 values of 14
and 2100 nM, respectively. Further investigation of the
substitution of the methyl group with other alkyl groups
on the quaternary ammonium nitrogen in 2a was
performed to optimize this moiety. Replacement of the
methyl group of 2a with an ethyl (2b), n-propyl (2c),
n-butyl (2d ), or 2-propenyl (2e) group suggested that
2c was optimal for binding affinity to both human and
mouse CCR1 receptors. Substitution with a benzyl
group led to a 26-fold decrease in binding affinity to
human receptors while maintaining the binding to
Biologica l P r op er ties. Compounds 1a -n and 2a -r
were screened for their inhibitory activity against 125I-
MIP-1R binding to both human and mouse CCR1
receptors. The selected compound was examined for its
functional antagonist activity in U937 cells transfected
with mouse and human CCR1 receptors, respectively.
Optimization of the lead compound 1a was initiated

A Novel CCR1 Antagonist
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1431
Ta ble 1. Binding Affinity to Human and Mouse CCR1 Receptorsa
binding affinity: IC50 (nM)
compd
R1
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-anthracenyl
diphenylmethyl
diphenylhydroxymethyl
2,7-dichloro-9-xanthenyl
2,7-dibromo-9-xanthenyl
9-xanthenyl
R2
% yield (method)
hCCR1
mCCR1
1a
1b
1c
1d
1e
1f
1g
1h
1i
1j
1k
1l
1m
1n
n-pentyl
cyclohexyl
cyclooctyl
cyclodecanyl
phenyl
2-naphthyl
cyclooctyl
cyclooctyl
cyclooctyl
cyclooctyl
cyclooctyl
81 (A)
76 (A)
50 (B)
93 (A)
94 (B)
51 (A)
49 (B)
78 (B)
45 (C)
83 (C)
68 (C)
73 (B)
82 (C)
83 (C)
510
200
140
>10000
>10000
>10000
>10000
>10000
>10000
>10000
>10000
>10000
>10000
>10000
590
800
>10000
>10000
>10000
1100
1600
>10000
5100
51
1-cyclooctenyl
1-cyclooctenyl
1-cyclooctenyl
2,7-dichloro-9-xanthenyl
2,7-dibromo-9-xanthenyl
240
150
1900
2500
Berlex compound
48
5000
a
The IC50 value of each compound is the mean of three assays.
Ta ble 2. Binding Affinity to Human and Mouse CCR1
mide class of compounds revealed that the cyclooctyl
moiety also played an important role in increasing the
binding potency to human CCR1 receptors and that the
putative hydrophobic site close to the cationic recogni-
tion site in the binding pocket of CCR1 receptors seemed
stringent. To further explore an alternative substituent
to the cyclooctyl moiety, a 1-cyclooctenyl group was
designed. The resulting compounds 1l-n exhibited
unexpectedly enhanced binding affinity to mouse recep-
tors, compared with 1c. Particularly, 1l was found to
be most potent in the tertiary amine series. Quaterna-
rization of 1l by a methyl (2n ), ethyl (2o), or n-propyl
(2p ) group revealed that an ethyl group appeared
optimal on the piperidinium nitrogen. Quaternarization
of 1m ,n by an ethyl group led to compounds 2q,r , which
showed high binding affinity for both human and mouse
receptors. In paticular, 2q seemed most attractive,
showing IC50 values of 1.2 and 12 nM for human and
mouse CCR1 receptors, respectively. Since the quater-
nary ammonium derivatives were a mixure of the two
isomers attributed to the 4-substituted piperidinium
structure, 2q was separated chromatographically to
provide 2q-112 and 2q-2, which were evaluated for their
binding affinity. The more active isomer 2q-1 showed
IC50 values of 0.9 and 5.8 nM for human and mouse
CCR1 receptors, respectively, while another isomer 2q-2
was 50- and 120-fold less active than 2q-1 for these
receptors, respectively.
Receptorsa
binding
affinity:
IC50 (nM)
%
compd
R1
9-xanthenyl
R3
yield hCCR1 mCCR1
2a
2b
2c
2d
2eb
2fb
2g
2h
2i
2j
2k
2l
2m
2n
2o
2p
2q
methyl
ethyl
n-propyl 62
n-butyl
allyl
benzyl
methyl
methyl
50
50
14
5.2
3.6
5.0
9.7
2100
660
270
380
670
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-xanthenyl
9-anthracenyl
diphenylmethyl
diphenylhydroxymethyl methyl
2,7-dichloro-9-xanthenyl methyl
2,7-dibromo-9-xanthenyl methyl
2,7-dibromo-9-xanthenyl ethyl
2,7-dibromo-9-xanthenyl n-propyl
6
21
80
370
1300
>10000
>10000
>10000
710
65 1800
70 800
55 2100
57
80
75
9
17
3.9
240
140
140
350
63
270
12
5.8
3.3
3.1
2.5
2.0
2.8
1.2
0.9
9-xanthenyl
9-xanthenyl
9-xanthenyl
methyl
ethyl
n-propyl 10
75
39
2,7-dichloro-9-xanthenyl ethyl
91
53
29
52
2q-1 2,7-dichloro-9-xanthenyl ethyl
2q-2 2,7-dichloro-9-xanthenyl ethyl
2r
47
1.9
740
12
2,7-dibromo-9-xanthenyl ethyl
a
The IC50 value of each compound is the mean of three assays.
The counteranion of the compound was Br-.
b
To determine whether the compound 2q-1 is also a
functional antagonist for CCR1 receptors, we measured
its ability to inhibit the MIP-1R-induced Ca2+ response
in U937 cells expressing human or mouse CCR1 recep-
tors. The IC50 values of 2q-1 were 0.73 and 21 nM for
inhibiting the MIP-1R-induced Ca2+ response in these
cells expressing human and mouse CCR1 receptors,
respectively, indicating that 2q-1 is a potent functional
CCR1 receptor antagonist.
mouse receptors. The substituents on the quaternary
ammonium nitrogen of 2a being fixed, the xanthene
moiety was again replaced with an anthracen-9-yl (2g),
diphenylmethyl (2h ), or diphenyl(hydroxy)methyl (2i).
This derivatization considerably lowered the binding
affinities. Unlike the tertiary amine 1n , a 2,7-dibro-
moxanathen-9-yl group (2k ) enhanced the binding af-
finity to both human and mouse CCR1 receptors. As the
substituent on the quaternary ammonium nitrogen of
2k , an n-propyl group (2m ) seemed optimal for human
receptors. Although 2m possessed highly potent binding
affinity for human receptors, its affinity for mouse CCR1
receptors was insufficient.
Finally, the selectivity of 2q-1 over some other
chemokine receptors was examined. Interestingly, 2q-1
was found to be a potent human CCR3 receptor antago-
nist because it inhibited 125I-Eotaxin binding to human
CCR3 receptors with an IC50 value of 0.58 nM. However,
2q-1 showed high selectivity for other CCR receptors
As described above, the SAR of the xanthenecarboxa-

1432 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Naya et al.
Ta ble 3. In Vitro Selectivity of 2q-1 against Some Chemokine
Receptors
carboxamide (510 mg, 1.25 mmol) in 10% HCl-MeOH (10 mL)
was stirred at room temperature for 20 h. The mixture was
concentrated in vacuo, and the residue was adjusted to pH 9
with saturated NaHCO3 and extracted with CHCl3. The
organic layer was dried (MgSO4) and concentrated in vacuo
to give N-(piperidin-4-yl)xanthene-9-carboxamide (546 mg,
76%) as a colorless solid: 1H NMR (CDCl3) δ 0.98-1.15 (m,
2H), 1.66-1.80 (m, 2H), 2.51-2.65 (m, 2H), 2.80-2.95 (m, 2H),
3.66-3.82 (m, 1H), 4.86 (s, 1H), 5.12 (d, J ) 8.0 Hz, 1H), 7.05-
7.16 (m, 4H), 7.25-7.45 (m, 4H); HRMS calcd for C19H21N2O2
(M + H)+ 309.1603, found 309.1597.
(iii) To a solution of N-(piperidin-4-yl)xanthene-9-carbox-
amide (100 mg, 0.32 mol) in CH2Cl2 (5.0 mL) were added
n-hexanal (60 mL, 0.50 mmol) and NaBH(OAc)3 (100 mg, 0.47
mmol) at room temperature, and the mixture was stirred for
20 h. After the addition of saturated NaHCO3 solution, the
mixture was extracted with CHCl3. The organic layer was
washed with brine, dried (MgSO4), and concentrated in vacuo.
The residue was purified by silica gel column chromatography
(3-5% MeOH in CHCl3) and triturated with i-PrOH to give
1a (103 mg, 81%) as a colorless solid: mp 213-214 °C; 1H NMR
(CDCl3) δ 0.85 (t, J ) 7.0 Hz, 3H), 1.15-1.90 (m, 12H), 1.95-
2.75 (m, 6H), 3.60-3.77 (m, 1H), 4.82 (s, 1H), 5.15 (d, J ) 5.7
Hz, 1H), 7.05-7.40 (m, 8H); HRMS calcd for C25H33N2O2 (M
+ H)+ 393.2542, found 393.2530. Anal. (C25H32N2O2‚0.33H2O)
C, H, N.
receptor
hCCR1
IC50 (nM)
receptor
hCCR2b
IC50 (nM)
0.90
>1000
0.73 (Ca2+ response)
5.8
mCCR1
hCCR3
mCCR3
hCCR4a
>10000
>1000
>1000
>10000
21 (Ca2+ response)
0.58
hCCR5
6.1 (Ca2+ response)
460
hCXCR1,2b
350 (Ca2+ response)
hCX3CR1c
a
Tarc-induced increases in intracellular Ca2+ concentrations
in KU812 cells. 125I-Interleukin-8 binding to human neutrophil
b
membranes. c Fractalkine-induced increases in Ca2+ concentra-
tions in HEL cells.
as shown in Table 3. These results suggested a high
degree of sequence homology between the binding sites
of human CCR1 and CCR3 receptors.13
Con clu sion
The initial screening of our compound libraries for
inhibitory activity against 125I-MIP-1R binding to hu-
man CCR1 receptors led to the identification of 1a as a
lead compound. Derivatization of 1a focusing on sub-
stitution on the piperidine nitrogen and installment of
substituents into the xanthene group resulted in the
discovery of 2q-1 showing potent antagonist activity
against not only human but also mouse CCR1 receptors.
Therefore, 2q-1 may be a useful tool for clarifying the
involvement of CCR1 receptors in mouse disease mod-
els.
The following compounds were prepared in a manner similar
to the procedure described for 1a using N-(piperidin-4-yl)-
xanthene-9-carboxamide and an appropriate aldehyde.
N-[1-(Cycloh exylm eth yl)piper idin -4-yl]xan th en e-9-car -
boxa m id e (1b). This was prepared from cyclohexylcarboxal-
dehyde (76%): mp 219-222 °C; 1H NMR (CDCl3) δ 0.77-0.84
(m, 2H), 1.12-1.26 (m, 4H), 1.34-1.39 (m, 1H), 1.57-1.75 (m,
10H), 1.89-1.96 (m, 2H), 2.51-2.56 (m, 2H), 3.63-3.68 (m,
1H), 4.84 (s, 1H), 5.08 (d, J ) 5.9 Hz, 1H), 7.08-7.14 (m, 4H),
7.25-7.31 (m, 2H), 7.36-7.40 (m, 2H); HRMS calcd for
C
26H33N2O2 (M + H)+ 405.2542, found 405.2526. Anal.
Exp er im en ta l Section
(C26H32N2O2‚0.5H2O) C, H, N.
Ma ter ia ls a n d Meth od s. All reagents and solvents were
of commercial quality and were used without further purifica-
tion unless otherwise noted. Melting points were determined
with a Yanaco MP micromelting point apparatus and were not
corrected. 1H NMR spectra were recorded on a Varian VXR
300 spectrometer with tetramethylsilane as an internal stan-
dard. Mass spectrometry was performed with a J EOL J MS-
SX102A spectrometer. Elemental analyses were performed on
an EA-1108 FISONS Instruments CHNSO analyzer and the
results were within 0.4% of calculated values. TLC was done
with Merck Kieselgel F254 precoated plates. Silica gel column
chromatography was carried out on Merck silica gel 60 (mesh
63-200 nm). Carboxylic acid fragments used for preparation
of the compounds shown in Tables 1 and 2 were commercially
available or were prepared using standard literature proce-
dures.
Gen er a l Meth od A. N-(1-n -Hexylp ip er id in -4-yl)xa n -
th en e-9-ca r boxa m id e (1a ). (i) N-(1-ter t-Bu tyloxyca r bo-
n ylp ip er id in -4-yl)xa n th en e-9-ca r boxa m id e. To a stirred
solution of xanthene-9-carboxylic acid (400 mg, 1.77 mmol) and
4-amino-1-tert-butoxycarbonylpiperidine14 (350 mg, 1.75 mmol)
in CHCl3 (20 mL) were added 1-hydroxybenzotriazole (350 mg,
2.59 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiim-
ide (500 mg, 2.61 mmol) at room temperature. After stirring
for 20 h, the reaction mixture was diluted with EtOAc, washed
with saturated NaHCO3 solution, 10% citric acid solution, and
brine, dried over MgSO4, and concentrated in vacuo. The
residue was purified by silica gel column chromatography (3%
MeOH in CHCl3) to give N-(1-tert-butyloxycarbonylpiperidin-
4-yl)xanthene-9-carboxamide (546 mg, 76%) as a colorless
solid: 1H NMR (CDCl3) δ 0.99-1.15 (m, 2H), 1.40 (s, 9H),
1.65-1.76 (m, 2H), 2.70-2.86 (m, 2H), 3.67-3.94 (m, 3H), 4.87
(s, 1H), 5.09 (d, J ) 7.8 Hz, 1H), 7.03-7.17 (m, 4H), 7.26-
7.41 (m, 4H); HRMS calcd for C24H29N2O4 (M + H)+ 409.2127,
found 409.2122.
N-[1-(Cyclod eca n ylm eth yl)p ip er id in -4-yl]xa n th en e-9-
ca r boxa m id e (1d ). This was prepared from cyclodecanylcar-
boxaldehyde (10) (93%): mp 191-193 °C; 1H NMR (CDCl3) δ
1.11-1.80 (m, 23H), 1.85-2.08 (m, 4H), 2.46-2.65 (m, 2H),
3.56-3.73 (m, 1H), 4.84 (s, 1H), 5.09 (d, J ) 7.2 Hz, 1H), 7.05-
7.16 (m, 4H), 7.24-7.33 (m, 2H), 7.35-7.42 (m, 2H); HRMS
calcd for C30H41N2O2 (M + H)+ 461.3168, found 461.3173. Anal.
(C30H40N2O2‚0.1iPrOH) C, H, N.
N-[1-(2-Naph th ylm eth yl)piper idin -4-yl]xan th en e-9-car -
boxa m id e (1f). This was prepared from 2-naphthaldehyde
(51%): mp 218-220 °C; 1H NMR (CDCl3) δ 1.12-1.32 (m, 2H),
1.67-1.80 (m, 2H), 1.98-2.16 (m, 2H), 2.50-2.72 (m, 2H), 3.55
(s, 2H), 3.59-3.80 (m, 1H), 4.84 (s, 1H), 5.10 (d, J ) 7.7 Hz,
1H), 7.00-7.85 (m, 15H); HRMS calcd for C30H29N2O2 (M +
H)+ 449.2229, found 449.2227. Anal. (C30H28N2O2) C, H, N.
Gen er al Meth od B. N-(1-Ben zylpiper idin -4-yl)xan th en e-
9-ca r boxa m id e (1e). To a stirred solution of xanthene-9-
carboxylic acid (3.0 g, 13.3 mmol) and 4-amino-1-benzyl-
piperidine (2.7 mL, 13.2 mmol) in DMF (60 mL) were added
1-hydroxybenzotriazole (3.0 mg, 19.6 mmol), 1-(3-dimeth-
ylaminopropyl)-3-ethylcarbodiimide (3.8 g, 19.8 mmol) and
triethylamine (3.7 mL, 34.1 mmol), and the mixture was
stirred at room temperature for 20 h. The solvent was removed
in vacuo, and the residue was diluted with EtOAc. The organic
layer was washed with saturated NaHCO3 solution and water,
dried (MgSO4), and concentrated in vacuo. The residue was
triturated with i-PrOH to give 1e (5.0 g, 94%) as a colorless
solid: mp 212-214 °C; 1H NMR (CDCl3) δ 1.12-1.28 (m, 2H),
1.67-1.79 (m, 2H), 1.94-2.09 (m, 2H), 2.50-2.68 (m, 2H), 3.39
(s, 2H), 3.59-3.76 (m, 1H), 4.84 (s, 1H), 5.08 (d, J ) 7.6 Hz,
1H), 7.00-7.41 (m, 13H); HRMS calcd for C26H27N2O2 (M +
H)+ 399.2073, found 399.2079. Anal. (C26H26N2O2‚0.5H2O) C,
H, N.
The following compounds were prepared in a manner similar
to general method B using the amine 4a or 4b and an
appropriate acid.
(ii) N-(P ip er id in -4-yl)xa n th en e-9-ca r boxa m id e. A solu-
tion of N-(1-tert-butyloxycarbonylpiperidin-4-yl)xanthene-9-

A Novel CCR1 Antagonist
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1433
N-[1-(Cyclooctylm eth yl)p ip er id in -4-yl]xa n th en e-9-ca r -
boxa m id e (1c). This was prepared from xanthene-9-carboxylic
acid and 4a (50%): mp 212-215 °C; 1H NMR (CDCl3) δ 1.11-
1.74 (m, 19H), 1.89-1.97 (m, 4H), 2.54-2.58 (m, 2H), 3.64-
3.66 (m, 1H), 4.84 (s, 1H), 5.10 (d, J ) 8.1 Hz, 1H), 7.08-7.14
(m, 4H), 7.26-7.33 (m, 2H), 7.37-7.40 (m, 2H); HRMS calcd
for C28H37N2O2 (M + H)+ 433.2855, found 433.2839. Anal.
(C28H36N2O2‚0.33H2O) C, H, N.
N-[1-(Cyclooct ylm et h yl)p ip er id in -4-yl]a n t h r a cen e-9-
ca r b oxa m id e (1g). This was prepared from anthracene-9-
carboxylic acid and 4a (49%): mp 186-189 °C; 1H NMR
(CDCl3) δ 1.12-1.95 (m, 17H), 2.02-2.40 (m, 6H), 2.75-3.00
(m, 2H), 4.25-4.45 (m, 1H), 5.96 (d, J ) 7.1 Hz, 1H), 7.35-
7.65 (m, 4H), 7.88-8.18 (m, 4H), 8.48 (s, 1H); HRMS calcd for
C29H37N2O (M +H)+ 429.2906,found 429.2906.Anal.(C29H36N2O‚
0.5H2O) C, H, N.
N-[1-(Cyclooct ylm et h yl)p ip er id in -4-yl]-2,2-d ip h en yl-
a ceta m id e (1h ). This was prepared from 2,2-diphenylacetic
acid and 4a (78%): mp 136-137 °C; 1H NMR (CDCl3) δ 1.11-
1.98 (m, 19H), 1.98-2.15 (m, 4H), 2.63-2.79 (m, 2H), 3.78-
3.95 (m, 1H), 4.90 (s, 1H), 5.44 (d, J ) 8.0 Hz, 1H), 7.18-7.35
(m, 10H); HRMS calcd for C28H39N2O (M + H)+ 419.3062, found
419.3060. Anal. (C28H38N2O) C, H, N.
(m, 10H), 1.85-2.03 (m, 2H), 2.05-2.17 (m, 4H), 2.50-2.68
(m, 2H), 2.75 (s, 2H), 3.60-3.77 (m, 1H), 4.74 (s, 1H), 5.12 (d,
J ) 8.6 Hz, 1H), 5.43 (t, J ) 7.5 Hz, 1H), 7.07 (d, J ) 8.7 Hz,
2H), 7.27 (dd, J ) 2.6, 8.7 Hz, 2H), 7.36 (d, J ) 2.6 Hz, 2H);
HRMS calcd for C28H33N2O235Cl2 (M + H)+ 499.1919, found
499.1917. Anal. (C28H32N2O2Cl2) C, H, N.
N-[1-(1-Cycloocten ylm eth yl)p ip er id in -4-yl]-2,7-d ibr o-
m oxa n th en e-9-ca r boxa m id e (1n ). This was prepared from
2,7-dibromoxanthene-9-carboxylic acid and 4b (83%): mp 220-
1
223 °C; H NMR (CDCl3) δ 1.15-1.35 (m, 2H), 1.35-1.52 (m,
8H), 1.70-1.84 (m, 2H), 1.86-2.02 (m, 2H), 2.03-2.20 (m, 4H),
2.49-2.68 (m, 2H), 2.74 (s, 2H), 3.60-3.75 (m, 1H), 4.73 (s,
1H), 5.11 (d, J ) 7.9 Hz, 1H), 5.43 (t, J ) 8.8 Hz, 1H), 7.01 (d,
J ) 8.8 Hz, 2H), 7.41 (dd, J ) 2.5, 8.8 Hz, 2H), 7.49 (d, J )
2.5 Hz, 2H); HRMS calcd for C28H33N2O279Br2 (M + H)+
587.0909, found 587.0914. Anal. (C28H32N2O2Br2) C, H, N.
Gen er a l Meth od D. 1-Cyclooctylm eth yl-1-m eth yl-4-
(xa n t h en e-9-ca r b oxa m id o)p ip er id in iu m Iod id e (2a ). A
mixture of 1c (167 mg, 386 mmol) and iodomethane (5.0 mL)
was stirred at room temperature for 20 h. The solvent was
removed in vacuo, and the residue was purified by silica gel
column chromatography (3-10% MeOH in CHCl3), and tritu-
ated with i-PrOH to give 2a (110 mg, 50%) as a colorless
solid: 1H NMR (CDCl3) δ 1.37-1.81 (m, 19H), 1.86-2.04 (m,
2H), 2.14-2.49 (m, 2H), 3.23 (s, 3H), 3.40-3.69 (m, 2H), 3.98-
4.26 (m, 1H), 5.17 & 5.41 (s, 1H), 6.90-7.60 (m, 8H), 8.25-
8.52 (m, 1H); HRMS calcd for C29H39N2O2 (M - I)+ 447.3012,
found 447.3001. Anal. (C29H39N2O2I‚0.33H2O) C, H, N.
The following compounds were prepared in a manner similar
to the procedure described for 2a .
N-[1-(1-Cycloocten ylm eth yl)p ip er id in -4-yl]xa n th en e-
9-ca r boxa m id e (1l). This was prepared from xanthene-9-
carboxylic acid and 4b (73%): mp 196-198 °C; 1H NMR
(CDCl3) δ 1.08-1.27 (m, 2H), 1.33-1.52 (m, 8H), 1.62-1.78
(m, 2H), 1.82-1.99 (m, 2H), 2.00-2.20 (m, 4H), 2.44-2.65 (m,
2H), 2.71 (s, 2H), 3.58-3.75 (m, 1H), 4.84 (s, 1H), 5.10 (d, J )
8.1 Hz, 1H), 5.40 (t, J ) 8.2 Hz, 1H), 7.10 (t, J ) 7.4 Hz, 2H),
7.13 (d, J ) 7.4 Hz, 2H), 7.29 (dd, J ) 7.4, 7.8 Hz, 2H), 7.38
(d, J ) 7.8 Hz, 2H); HRMS calcd for C28H35N2O2 (M + H)+
431.2699, found 431.2678. Anal. (C28H34N2O2) C, H, N.
Gen er a l Meth od C. N-[1-(Cyclooctylm eth yl)p ip er id in -
4-yl]-2,7-d ich lor oxa n th en e-9-ca r boxa m id e (1j). A solution
of 2,7-dichloroxanthene-9-carboxylic acid15 (500 mg, 1.69 mmol)
and 1,1′-carbonyldiimidazole (330 mg, 2.04 mmol) in THF (20
mL) were stirred at room temperature for 1 h. To this mixture
was added 4a (500 mg, 1.69 mmol), and the mixture was
stirred for 12 h. The mixture was diluted with EtOAc and
washed with saturated NaHCO3 solution and brine, dried
(MgSO4), and concentrated in vacuo. The residue was purified
by silica gel column chromatography (3% MeOH in CHCl3),
and triturated with i-PrOH to give 1j (700 mg, 83%) as a
colorless solid: mp 217-220 °C; 1H NMR (CDCl3) δ 1.15-2.13
(m, 23H), 2.52-2.70 (m, 2H), 3.69-3.75 (m, 1H), 4.73 (s, 1H),
5.11 (d, J ) 8.8 Hz, 1H), 7.07 (d, J ) 8.6 Hz, 2H), 7.27 (dd, J
) 2.7, 8.6 Hz, 2H), 7.35 (d, J ) 2.7 Hz, 2H); HRMS calcd for
1-Cyclooctylm eth yl-1-eth yl-4-(xa n th en e-9-ca r boxa m i-
d o)p ip er id in iu m Iod id e (2b). This was prepared from 1c
and iodoethane (50%, colorless solid): 1H NMR (CDCl3) δ
1.18-2.03 (m, 24H), 2.15-2.51 (m, 2H), 3.05-3.79 (m, 4H),
3.85-4.30 (m, 1H), 5.18 & 5.42 (s, 1H), 6.80-7.60 (m, 8H),
8.33 & 8.55 (d, J ) 7.7 Hz, 1H); HRMS calcd for C30H41N2O2
(M - I)+ 461.3168, found 461.3172. Anal. (C30
H41N2O2I) C, H,
N.
1-Cyclooctylm eth yl-1-n -p r op yl-4-(xa n th en e-9-ca r box-
a m id o)p ip er id in iu m Iod id e (2c). This was prepared from
1c and 1-iodopropane (62%, colorless solid): 1H NMR (CD3-
OD) δ 1.03 & 1.05 (t, J ) 7.3 Hz, 3H), 1.30-2.20 (m, 21H),
3.05-3.65 (m, 8H), 3.85-3.98 (m, 1H), 4.56 (s, 1H), 7.06-7.45
(m, 8H); HRMS calcd for C31H43N2O2 (M - I)+ 475.3325, found
475.3329. Anal. (C31H43N2O2I) C, H, N.
1-n -Bu t yl-1-cyclooct ylm et h yl-4-(xa n t h en e-9-ca r b ox-
a m id o)p ip er id in iu m Iod id e (2d ). This was prepared from
1c and 1-iodobutane (6%, colorless solid): 1H NMR (CD3OD)
δ 1.01 & 1.03 (t, J ) 7.3 Hz, 3H), 1.09-2.09 (m, 23H), 3.14-
3.68 (m, 8H), 3.85-4.00 (m, 1H), 4.94 & 4.97 (s, 1H), 7.15-
7.40 (m, 8H); HRMS calcd for C32H45N2O2 (M - I)+ 489.3481,
found 489.3493. Anal. (C32H45N2O2I‚0.33H2O) C, H, N.
1-Allyl-1-cyclooct ylm et h yl-4-(xa n t h en e-9-ca r b oxa m i-
d o)p ip er id in iu m Br om id e (2e). This was prepared from 1c
and 3-bromopropene (21%, colorless solid): 1H NMR (CDCl3)
δ 1.22-2.41 (m, 19H), 3.00-4.05 (m, 9H), 5.29 & 5.47 (s, 1H),
5.65-6.10 (m, 3H), 6.80-7.80 (m, 8H), 9.15 & 9.52 (d, J ) 8.5
Hz, 1H); HRMS calcd for C31H41N2O2 (M - Br)+ 473.3168,
found 473.3171. Anal. (C31H41N2O2Br) C, H, N.
C
28H35N2O235Cl2 (M + H)+ 501.2076, found 501.2074. Anal.
(C28H34N2O2Cl2) C, H, N.
The following compounds were prepared in a manner similar
to the procedure described for 1j using the amine 4a or 4b
and appropriate acid.
N-[1-(Cyclooctylm eth yl)p ip er id in -4-yl]-2,2-d ip h en yl-2-
h yd r oxya ceta m id e (1i). This was prepared from 2,2-diphe-
1
nyl-2-hydroxyacetic acid and 4a (45%): mp 146-148 °C; H
NMR (CDCl3) δ 1.10-1.99 (m, 19H), 1.99-2.22 (m, 4H), 2.63-
2.78 (m, 2H), 3.75-3.92 (m, 1H), 3.82-4.15 (m, 1H), 6.18 (d,
J
C
) 7.9 Hz, 1H), 7.26-7.49 (m, 10H); HRMS calcd for
28H39N2O2 (M + H)+ 435.3012, found 435.3010. Anal.
1-Be n zyl-1-cyclooct ylm e t h yl-4-(xa n t h e n e -9-ca r b ox-
a m id o)p ip er id in iu m Br om id e(2f). This was prepared from
1c and benzyl bromide (80%, colorless solid): 1H NMR (CD3-
OD) δ 1.25-1.42 (m, 19H), 3.00-4.05 (m, 7H), 4.59 & 4.74 (s,
2H), 5.00 (s, 1H), 7.00-7.38 (m, 8H), 7.43-7.65 (m, 5H):
(C28H38N2O2) C, H, N.
N-(1-Cyclooctylm eth ylp ip er id in -4-yl)-2,7-d ibr om oxa n -
th en e-9-ca r boxa m id e (1k ). This was prepared from 2,7-
dibromoxanthene-9-carboxylic acid16 and 4a (68%): mp 237-
240 °C; 1H NMR (CDCl3) δ 1.09-1.95 (m, 19H), 1.95-2.07 (m,
4H), 2.55-2.69 (m, 2H), 3.60-3.78 (m, 1H), 4.73 (s, 1H), 5.12
(d, J ) 8.0 Hz, 1H), 7.01 (d, J ) 8.6 Hz, 2H), 7.41 (dd, J ) 2.3,
8.6 Hz, 2H), 7.50 (d, J ) 2.3 Hz, 2H); HRMS calcd for
HRMS calcd for
523.3315. Anal. (C35H43N2O2Br‚0.5H2O) C, H, N.
C
35H43N2O2 (M - Br)+ 523.3325, found
1-Cyclooctylm eth yl-1-m eth yl-4-(a n th r a cen e-9-ca r box-
a m id o)p ip er id in iu m Iod id e (2g). This was prepared from
1g and iodomethane (65%, colorless solid): 1H NMR (DMSO-
d6) δ 1.30-2.40 (m, 19H), 3.01 & 3.11 (s, 3H), 3.13-3.35 (m,
2H), 3.45-3.52 (m, 4H), 4.30-4.50 (m, 1H), 7.50-7.64 (m, 4H),
7.90-8.19 (m, 4H), 8.69 (s, 1H), 8.80-8.90 (m, 1H); HRMS
calcd for C30H39N2O (M - I)+ 443.3062, found 443.3066. Anal.
(C30H39N2OI) C, H, N.
C
28H35N2O279Br2 (M + H)+ 589.1065, found 589.1081. Anal.
(C28H34N2O2Br2) C, H, N.
N -[1-(1-Cyclooct e n ylm e t h yl)p ip e r id in -4-yl]-2,7-d i-
ch lor oxa n th en e-9-ca r boxa m id e (1m ). This was prepared
from 2,7-dichloroxanthene-9-carboxylic acid and 4b (82%): mp
212-213 °C; 1H NMR (CDCl3) δ 1.15-1.35 (m, 2H), 1.35-1.85

1434 J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9
Naya et al.
1-Cyclooctylm eth yl-1-m eth yl-4-(2,2-d ip h en yla ceta m i-
d o)p ip er id in iu m Iod id e (2h ). This was prepared from 1h
and iodomethane (70%, colorless solid): 1H NMR (DMSO-d6)
δ 1.31-2.19 (m, 19H), 2.99 & 3.03 (s, 3H), 3.15-3.52 (m, 6H),
3.75-3.95 (m, 1H), 4.93 & 4.95 (s, 1H), 7.15-7.36 (m, 10H),
8.27 & 8.33 (d, J ) 7.4 Hz, 1H); HRMS calcd for C29H41N2O
(M - I)+ 433.3219, found 433.3215. Anal. (C29H41N2OI) C, H,
N.
8.72 (d, J ) 8.4 Hz, 1H); HRMS calcd for C31H41N2O2 (M - I)+
473.3168, found 473.3183. Anal. (C31H41N2O2I) C, H, N.
1-(1-Cyclooct en ylm et h yl)-1-et h yl-4-(2,7-d ich lor oxa n -
th en e-9-ca r boxa m id o)p ip er id in iu m Iod id e (2q). This was
prepared from 1m and iodoethane (91%, colorless solid): 1H
NMR (CDCl3) δ 1.35 & 1.40 (t, J ) 7.3 Hz, 3H), 1.25-1.74 (m,
8H), 1.96-2.60 (m, 8H), 3.22-3.86 (m, 6H), 3.82 & 4.24 (s,
2H), 4.15-4.40 (m, 1H), 5.28 & 5.69 (s, 1H), 6.07 & 6.26 (t, J
) 8.2 Hz, 1H), 6.96 & 7.00 (d, J ) 8.7 Hz, 2H), 7.16 (dd, J )
2.4, 8.7 Hz, 2H), 7.39 & 7.51 (d, J ) 2.4 Hz, 2H), 8.80 & 9.08
(d, J ) 7.8 Hz, 1H); HRMS calcd for C30H37N2O235Cl2 (M - I)+
527.2232, found 527.2234. Anal. (C30H37N2O2Cl2I‚0.5H2O) C,
H, N.
Sep a r a tion of Ma jor Isom er 2q-1 a n d Min or Isom er
2q-2. 2q (5.9 g) was separated by silica gel column chroma-
tography (30-50% acetone in CHCl3) and triturated with
i-PrOH to give major isomer 2q-1 (3.5 g, 59%) and minor
isomer 2q-2 (1.9 g, 32%), respectively, as a colorless solid. 2q-
1: mp 148-150 °C; 1H NMR (CDCl3) δ 1.40 (t, J ) 7.3 Hz,
3H), 1.25-1.67 (m, 8H), 1.96-2.60 (m, 8H), 3.55-3.86 (m, 6H),
3.82 (s, 2H), 4.15-4.30 (m, 1H), 5.28 (s, 1H), 6.07 (t, J ) 8.2
Hz, 1H), 6.96 (d, J ) 8.7 Hz, 2H), 7.16 (dd, J ) 2.4, 8.7 Hz,
2H), 7.39 (d, J ) 2.4 Hz, 2H), 8.80 (d, J ) 7.8 Hz, 1H); HRMS
calcd for C30H37N2O235Cl2 (M - I)+ 527.2232, found 527.2234.
Anal. (C30H37N2O2Cl2I‚0.5H2O) C, H, N. 2q-2: mp 146-148
°C; 1H NMR (CDCl3) δ 1.35 (t, J ) 7.1 Hz, 3H), 1.38-1.74 (m,
8H), 1.98-2.45 (m, 8H), 3.22-3.40 (m, 4H), 4.24 (s, 2H), 4.38-
4.40 (m, 1H), 4.41-4.60 (m, 2H), 5.69 (s, 1H), 6.26 (t, J ) 8.2
Hz, 1H), 7.00 (d, J ) 8.7 Hz, 2H), 7.17 (dd, J ) 2.5, 8.7 Hz,
2H), 7.51 (d, J ) 2.5 Hz, 2H), 9.08 (d, J ) 8.6 Hz, 1H); HRMS
calcd for C30H37N2O235Cl2 (M - I)+ 527.2232, found 527.2234.
Anal. (C30H37N2O2Cl2I‚0.5H2O) C, H, N.
1-Cyclooctylm eth yl-1-m eth yl-4-(2,2-diph en yl-2-h ydr oxy-
a cet a m id o)p ip er id in iu m Iod id e (2i). This was prepared
from 1i and iodomethane (55%, colorless solid): 1H NMR
(DMSO-d6) δ 1.20-2.20 (m, 19H), 3.03 (s, 3H), 3.10-3.54 (m,
6H), 3.85-4.05 (m, 1H), 6.81 & 6.82 (s, 1H), 7.20-7.48 (m,
10H), 8.20 & 8.29 (d, J ) 8.9 Hz, 1H); HRMS calcd for
C
29H41N2O2 (M - I)+ 449.3168, found 449.3165. Anal. (C29H41
-
N2O2I) C, H, N.
1-Cyclooctylm eth yl-1-m eth yl-4-(2,7-d ich lor oxa n th en e-
9-ca r boxa m id o)p ip er id in iu m Iod id e (2j). This was pre-
pared from 1j and iodomethane (57%, colorless solid): 1H NMR
(DMSO-d6) δ 1.20-2.18 (m, 19H), 3.02 (s, 3H), 3.11-3.53 (m,
6H), 3.65-3.83 (m, 1H), 4.91 (s, 1H), 7.16-7.47 (m, 6H), 8.41
(d, J ) 5.9 Hz, 1H); HRMS calcd for C29H37N2O235Cl2 (M - I)+
515.2232, found 515.2236. Anal. (C29H37N2O2Cl2I‚1.0H2O‚1.0i-
PrOH) C, H, N.
1-Cyclooctylm eth yl-1-m eth yl-4-(2,7-d ibr om oxa n th en e-
9-ca r boxa m id o)p ip er id in iu m Iod id e (2k ). This was pre-
pared from 1k and iodomethane (80%, colorless solid): 1H
NMR (CD3OD) δ 1.24-2.25 (m, 19H), 3.10 & 3.12 (s, 3H),
3.20-3.65 (m, 6H), 3.80-3.96 (m, 1H), 4.88 (s, 1H), 7.05-7.55
(m, 6H); HRMS calcd for C29H37N2O279Br2 (M - I)+ 603.1222,
found 603.1218. Anal. (C29H37N2O2Br2I) C, H, N.
1-Cyclooctylm eth yl-1-eth yl-4-(2,7-d ibr om oxa n th en e-9-
ca r boxa m id o)p ip er id in iu m Iod id e (2l). This was prepared
from 1k and iodoethane (75%, colorless solid): 1H NMR
(CDCl3) δ 1.29 & 1.36 (t, J ) 7.1 Hz, 3H), 1.38-2.50 (m, 19H),
3.21 & 3.58 (d, J ) 4.3 Hz, 2H), 3.36-3.69 (m, 2H), 3.43 &
3.82 (q, J ) 7.1 Hz, 2H), 3.88-4.41 (m, 3H), 5.39 & 5.57 (s,
1H), 6.91 & 6.92 (d, J ) 8.7 Hz, 2H), 7.30 & 7.31 (dd, J ) 2.4,
8.7 Hz, 2H), 7.55 & 7.61 (d, J ) 2.4 Hz, 2H), 8.88 & 9.12 (d, J
) 8.6 Hz, 1H); HRMS calcd for C30H39N2O279Br2 (M - I)+
617.1378, found 613.1384. Anal. (C30H39N2O2Br2I) C, H, N.
1-(1-Cyclooct en ylm et h yl)-1-et h yl-4-(2,7-d ib r om oxa n -
th en e-9-ca r boxa m id o)p ip er id in iu m Iod id e (2r ). This was
prepared from 1n and iodoethane (52%, colorless solid): 1H
NMR (CDCl3) δ 1.09-1.78 (m, 11H), 1.89-2.55 (m, 8H), 3.29-
4.35 (m, 7H), 3.86 & 4.17 (s, 2H), 5.18 & 5.65 (s, 1H), 6.04 &
6.19 (t, J ) 8.3 Hz, 1H), 6.86 & 6.89 (d, J ) 8.7 Hz, 2H), 7.29
(dd, J ) 2.3, 8.7 Hz, 2H), 7.47 & 7.62 (d, J ) 2.3 Hz, 2H), 8.70
& 8.98 (d, J ) 7.9 Hz, 1H); HRMS calcd for C30H37N2O279Br2
(M - I)+ 615.1222, found 615.1221. Anal. (C30H37N2O2Br2I) C,
H, N.
1-Cyclooctylm eth yl-1-n -pr opyl-4-(2,7-dibr om oxan th en e-
9-ca r boxa m id o)p ip er id in iu m Iod id e (2m ). This was pre-
pared from 1k and 1-iodopropane (9%, colorless solid): 1H
NMR (CDCl3) δ 1.07 &1.13 (t, J ) 7.1 Hz, 3H), 0.90-2.53 (m,
21H), 3.10-4.46 (m, 9H), 5.36 & 5.67 (s, 1H), 6.90 & 6.93 (d,
J ) 8.7 Hz, 2H), 7.29 & 7.31 (dd, J ) 2.4, 8.7 Hz, 2H), 7.56 &
7.63 (d, J ) 2.4 Hz, 2H), 8.84 & 9.04 (d, J ) 8.4 Hz, 1H); HRMS
calcd for C31H41N2O279Br2 (M - I)+ 631.1535, found 631.1539.
Anal. (C31H41N2O2Br2I) C, H, N.
1-(1-Cycloocten ylm eth yl)-1-m eth yl-4-(xa n th en e-9-ca r -
boxa m id o)p ip er id in iu m Iod id e (2n ). This was prepared
from 1l and iodomethane (75%, colorless solid): 1H NMR
(CDCl3) δ 1.30-2.49 (m, 16H), 2.90 & 3.13 (s, 3H), 3.31-3.68
(m, 4H), 3.82 & 4.18 (s, 2H), 3.92-4.30 (m, 1H), 5.14 & 5.42
(s, 1H), 5.99 & 6.12 (t, J ) 8.3 Hz, 1H), 6.80-7.60 (m, 8H),
8.26 & 8.52 (d, J ) 8.3 Hz, 1H); HRMS calcd for C29H37N2O2
(M - I)+ 445.2855, found 445.2858. Anal. (C29H37N2O2I‚
0.33H2O) C, H, N.
1-(1-Cyclooct en ylm et h yl)-1-et h yl-4-(xa n t h en e-9-ca r -
boxa m id o)p ip er id in iu m iod id e (2o). This was prepared
from 1l and iodoethane (39%, colorless solid): 1H NMR (CDCl3)
δ 1.23 & 1.24 (t, J ) 7.3 Hz, 3H), 1.35-2.50 (m, 16H), 3.23-
4.32 (m, 7H), 3.70 & 4.08 (s, 2H), 5.11 & 5.44 (s, 1H), 5.96 &
6.15 (t, J ) 8.2 Hz, 1H), 6.80-7.60 (m, 8H), 8.34 & 8.75 (d, J
) 7.8 Hz, 1H); HRMS calcd for C30H39N2O2 (M - I)+ 459.3012,
found 459.3012. Anal. (C30H39N2O2I) C, H, N.
1-(1-Cyclooct en ylm et h yl)-1-n -p r op yl-4-(xa n t h en e-9-
ca r boxa m id o)p ip er id in iu m Iod id e (2p ). This was prepared
from 1l and 1-iodopropane (10%, colorless solid): 1H NMR
(CDCl3) δ 1.02 & 1.08 (t, J ) 6.7 Hz, 3H), 1.29-2.68 (m, 18H),
2.99-4.38 (m, 7H), 3.71 & 4.16 (m, 2H), 5.10 & 5.51 (s, 1H),
5.96 & 6.15 (t, J ) 8.3 Hz, 1H), 6.92-7.58 (m, 8H), 8.31 &
4-ter t-Bu toxyca r bon yla m in o-1-(cyclooctylm eth yl)p ip -
er id in e (6a ). This was prepared in a manner similar to the
procedure described for 1a using 4-tert-butoxycarbonylami-
nopiperidine17 and cyclooctanecarboxaldehyde (95%, colorless
solid): 1H NMR (CDCl3) δ 0.92-1.70 (m, 19H), 1.44 (s, 9H),
1.75-2.10 (m, 4H), 2.62-2.80 (m, 2H), 3.28-3.52 (m, 1H),
4.30-4.55 (m, 1H); HRMS calcd for C19H37N2O2 (M + H)+
325.2855, found 325.2853.
4-Am in o-1-(cyclooctylm eth yl)p ip er id in e (4a ). This was
prepared in a manner similar to the procedure described for
N-(piperidin-4-yl)xanthene-9-carboxamide using 6a (88%, col-
orless oil): 1H NMR (CDCl3) δ 1.09-1.82 (m, 21H), 1.85-2.01
(m, 2H), 2.03-2.12 (m, 2H), 2.55-2.70 (m, 1H), 2.72-2.85 (m,
2H); HRMS calcd for C14H29N2 (M + H)+ 225.2331, found
225.2328.
4-ter t-Bu toxyca r bon yla m in o-1-(1-cycloocten ylm eth yl)-
p ip er id in e (6b). This was prepared in a manner similar to
the procedure described for 1a using 4-tert-butoxycarbonyl-
aminopiperidine and 9 (88%, colorless solid): 1H NMR (CDCl3)
δ 1.30-1.58 (m, 10H), 1.44 (s, 9H), 1.80-2.25 (m, 8H), 2.66-
2.85 (m, 2H), 2.79 (s, 2H), 3.34-3.55 (m, 1H), 4.33-4.54 (m,
1H), 5.46 (t, J ) 8.1 Hz, 1H); HRMS calcd for C19H35N2O2 (M
+ H)+ 323.2699, found 323.2698.
4-Am in o-1-(1-cycloocten ylm eth yl)p ip er id in e (4b). This
was prepared in a manner similar to the procedure described
for N-(piperidin-4-yl)xanthene-9-carboxamide using 6b (96%,
colorless oil): 1H NMR (CDCl3) δ 1.20-1.61 (m, 10H), 1.65-
1.98 (m, 4H), 2.00-2.28 (m, 4H), 2.50-2.70 (m, 1H), 2.70-
2.90 (m, 2H), 2.80 (s, 2H), 5.46 (t, J ) 7.7 Hz, 1H); HRMS
calcd for C14H27N2 (M + H)+ 223.2174, found 223.2175.
1-Cycloocten ylca r boxa ld eh yd e (9). To a stirred suspen-
sion of cyclooctanone p-tolylsulfonylhydrazone18 (12 g, 40.8

A Novel CCR1 Antagonist
J ournal of Medicinal Chemistry, 2001, Vol. 44, No. 9 1435
mmol) in N,N,N′,N′-tetramethylethylenediamine (120 mL) was
added 1.6 M of n-BuLi in hexane (100 mL, 160 mmol) at -55
to -45 °C under N2. The resulting deep red solution was
stirred at -45 °C for 0.5 h, and then allowed to warm to room
temperature over a period of 1 h. When N2 evolution had
ceased, the mixture was cooled at 0 °C, and DMF (15 mL, 204
mmol) was added. After the mixture was stirred for 1 h, the
reaction was quenched by adding water. The mixture was
extracted with EtOAc, and the organic layer was washed with
2 N HCl and brine, dried (MgSO4), and concentrated in vacuo.
The residue was purified by silica gel column chromatography
(3% EtOAc in hexane) to give 9 (3.0 g, 53%) as a colorless oil:
1H NMR (CDCl3) δ 1.39-1.74 (m, 8H), 2.38-2.51 (m, 4H), 6.72
(t, J ) 8.2 Hz, 1H), 9.41 (s, 1H).
1-Cyclod eca n ylca r boxa ld eh yd e (10). To a stirred solu-
tion of diethyl (isocyanomethyl)phosphonate (320 µL, 2.00
mmol) in THF (5.0 mL) was added 2.5 M n-BuLi in hexane
(0.75 mL, 1.88 mmol) at -70 °C under N2, and the resulting
solution was stirred at the same temperature for 30 min. To
this solution was added cyclodecanone (250 µL, 1.55 mmol),
and the mixture was stirred for 30 min. The reaction was
quenched by adding 1 N HCl, and the mixture was extracted
with EtOAc. The organic layer was washed with brine, dried
(MgSO4), and concentrated in vacuo. To the residue in Et2O
(10 mL) was added concentrated HCl (10 mL), and the mixture
was stirred for 12 h. The mixture was extracted with Et2O,
and the organic layer was washed with water and brine, dried
(MgSO4), and concentrated in vacuo. The residue was purified
by silica gel column chromatography (3% EtOAc in hexane)
to give 10 (150 mg, 58%) as a yellow oil: 1H NMR (CDCl3) δ
1.39-2.00 (m, 18H), 2.41-2.70 (m, 1H), 9.59-9.63 (m, 1H).
125I-Ch em ok in e Bin d in g Stu d y. The cell-based binding
assays were performed in 96-well microplates in a total volume
of 400 µL. CHO cells transfected with CCR receptors were
detached by PBS (-) containing 2 mM EDTA and resuspended
in binding buffer (Krebs-Linger phosphate buffer containing
0.1% BSA and 0.1% glucose). CHO cells (1 × 105 cells) were
incubated with 50 pM 125I-chemokine and an antagonist or an
unlabeled chemokine for 1 h at 37 °C in the binding buffer to
reach equilibrium. Nonspecific binding was determined in the
presence of 100 nM of unlabeled chemokine. After incubation,
the ice-cold binding buffer was added to the binding reaction.
Then, the binding reaction was filtered by GF/C glass fiber
filter (Whatman International Ltd., Maidstone, U.K.) pre-
soaked with 1% polyethylenimine to reduce nonspecific binding
to the glass filter. The radioactivity on the glass filter was
determined with a gamma counter (COBRA 5002, Packard,
Downers Grove, IL).
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Ack n ow led gm en t. We are grateful to Ms. A. Dob-
bins, Merck & Co. Inc., for her critical reading of this
manuscript.
J M0004244