(Aryloxyacetylamino)benzoic acid analogues: A new class of hypoxia-inducible factor-1 inhibitors

Article abstract of DOI:10.1021/jm0610292

Structural modification of a compound discovered during screening using an HRE-dependent reporter assay has revealed a novel class of HIF-1 inhibitors, which potently inhibit the HIF-1α protein accumulation and its target gene expression under hypoxic conditions in human hepatocellular carcinoma Hep3B cells.

Full text of DOI:10.1021/jm0610292

J. Med. Chem. 2007, 50, 1675-1684
1675
(Aryloxyacetylamino)benzoic Acid Analogues: A New Class of Hypoxia-Inducible Factor-1
Inhibitors
Kyeong Lee, Jeong Hyung Lee, Shanthaveerappa K. Boovanahalli, Yinglan Jin, Mijeoung Lee, Xuejun Jin, Jin Hwan Kim,
Young-Soo Hong, and Jung Joon Lee*
Molecular Cancer Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea, 305-806
ReceiVed August 28, 2006
Structural modification of a compound discovered during screening using an HRE-dependent reporter assay
has revealed a novel class of HIF-1 inhibitors, which potently inhibit the HIF-1R protein accumulation and
its target gene expression under hypoxic conditions in human hepatocellular carcinoma Hep3B cells.
Development of intratumoral hypoxia is a hallmark of rapidly
growing solid tumors and of their metastases. Hypoxic tumor
cells are resistant to conventional chemotherapy and radio-
therapy1-3 and consequently the presence of hypoxia in tumors
plays a negative role in patient prognosis. A key modulator
expressed in many cancer cells in response to hypoxic stress is
hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcription
factor that consists of an HIF-1R subunit and a HIF-1â subunit,
both of which are members of the basic helix-loop-helix PER/
Figure 1. Compound 1 and its isomers.
Arnt/Sim (bHLH-PAS) transcription family. HIF-1â is also
known as the aryl hydrocarbon nuclear translocator (ARNT).
HIF-1 activity is dependent on the availability of the HIF-1R
subunit, which is regulated by cellular oxygen levels. At normal
oxygen levels, HIF-1R is degraded via the pVHL-mediated
ubiquitin-proteosomal pathway. Under hypoxic conditions,
however, HIF-1R rapidly accumulates in the cell and dimerizes
with HIF-1â, which is constitutively expressed.4 Binding of
HIF-1 with co-activators to a specific DNA sequence within
the target gene promoter, called the hypoxia-responsive elements
(HRE), leads to transcriptional activation of a variety of genes
involved in angiogenesis, glycolysis, growth factor signaling,
tumor invasion, and metastasis.5 In many cancers, the HIF-1
pathway is not only activated by low oxygen tension but is also
induced or amplified by a wide range of growth-promoting
stimuli and oncogenic signals. Clinically, HIF-1R overexpression
has been shown to be a marker of highly aggressive cancers,6
and inhibition of HIF-1 production and function significantly
reduces tumor growth in animal models.7 Accordingly, HIF-1
represents an attractive molecular target for the development
of novel anticancer agents.8
In recent years, a number of anticancer agents have been
identified as inhibitors of HIF-1 activity.9 All of these inhibitors
share in common an ability to decrease HIF-1R protein levels,
inhibit the expression of HIF-1 target genes, such as VEGF and
EPO, and impair tumor growth in animal models. In addition,
a number of inhibitors targeting the HIF regulation pathways10-13
as well as signal-transduction pathways8,14-15 have also been
reported.
As part of our ongoing efforts to identify small-molecule
HIF-1 inhibitors, we have carried out a high-throughput cell-
based reporter assay for our chemical library in human hepa-
tocellular carcinoma Hep3B cells. The activity of HIF-1 was
monitored using a luciferase reporter gene under the control of
HRE from the VEGF gene.16 This resulted in the identification
of several hits. Among these, compound 1 (Figure 1) with an
IC50 value of 5.0 µM in Hep3B cells was chosen as a starting
point for the generation of a new class of HIF-1 inhibitors,
because of its unique structure and its synthetic accessibility.
Herein, we report the discovery of novel class of HIF-1
inhibitors identified by structural modification of 1.
The synthesis of compound 1 and its analogues 8-10 was
accomplished as outlined in Scheme 1. Reaction of appropriate
phenols 4 with ethyl chloroacetate followed by saponification
yielded the required intermediates 5. Compounds 9b,c were
commercially available and synthesis of compounds 9d-i has
been reported elsewhere.17 Coupling of 6 with the appropriate
aryloxyacetic acids 5a,d-i, furnished the corresponding esters
8a,d-i, which upon subsequent alkaline hydrolysis provided the
corresponding acids 1, 9d-i. A similar sequence of reactions
was followed to obtain ortho and para derivatives of 1 (2 and
3 respectively, Figure 1). Compound 1 was further coupled with
appropriate amines to obtain the respective amide derivatives
11-14. A single-step coupling of 7 with the appropriate
aryloxyacetic acids 5a-d,j produced the corresponding amides
10a-d,j, respectively. The Suzuki cross-coupling18 of methyl
3-(2-(4-bromophenoxy)acetamido)benzoate 8h with the ap-
propriate aryl boronic acids followed by subsequent alkaline
hydrolysis afforded cross-coupled products 15-18.
Scheme 2 describes the synthesis of the hydroxylated
analogues 23-30. Compound 19 underwent benzylation, fol-
lowed by hydrolysis to produce 20, which upon subsequent
protection with trimethylsilyl ethanol and hydrogenolysis fur-
nished 22. Coupling of adamantyl phenoxyacetic acid 5a with
amine intermediates 21 or 22 gave the corresponding esters 23
and 24, respectively. The benzoic acid 25 was readily obtained
from the trimethylsilylethyl (TME) ester 24 in higher yields
than from the corresponding methyl ester 23 (79% vs 5.5%).
Reaction of ester 23 with the appropriate amines in the presence
of trimethylaluminum afforded the corresponding amide deriva-
tives 26-28. Compounds 29 and 30 were prepared under usual
coupling conditions from the acid 25.
* Corresponding author. Tel: +82-42-860-4360, fax: +82-42-860-4595,
e-mail: jjlee@kribb.re.kr.
10.1021/jm0610292 CCC: $37.00 © 2007 American Chemical Society
Published on Web 03/01/2007

1676 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7
Lee et al.
Scheme 1a
a Reaction conditions: (a) (i) Ethyl chloroacetate, K2CO3, DMF; (ii) LiOH·H2O, dioxane, H2O; (b) EDCI, HOBT, DIPEA, DMF; (c) LiOH·H2O, dioxane,
H2O; (d) 1, ArNH2, EDCI, HOBT, DIPEA, DMF; (e) (i) 8h, R ) Br, X ) OCH3, (PPh3)4Pd, NaHCO3, H2O/DME, or [bmim][BF4]; (ii) LiOH·H2O, dioxane,
H2O.
Scheme 2a
isomer 1, suggesting that the compound with the carboxylic acid
moiety at the meta position is the best isomer for inhibitory
activity. Subsequently, we investigated the effects of different
aromatic substituents on the adamantyl phenyl ring A, retaining
the carboxyl group at the meta position of ring B. Almost all
derivatives 9b-i, 15-18, with various functionalities, displayed
poor inhibitory activity in both the cell lines, with the exception
of compounds 9h and 9i, which demonstrated considerable
inhibitory potency in the AGS cell line. These results strongly
suggested that the replacement of adamantyl group with a
substituted phenyl ring caused a significant loss of activity and
that the presence of the adamantyl substituent, or an equivalent,
on ring A is essential for effective inhibition of HIF-1 activation
in hypoxia.
The m-aminobenzamide derivative 10a, which was moder-
ately active in Hep3B cell line, demonstrated appreciably more
inhibitory potency relative to 1 in AGS cell line. On the basis
of increased inhibitory potency of 10a, we substituted adamantyl
group with a proton or with different functional groups (10b-
d, j) while retaining the acylamino moiety meta to the carboxyl
group in ring B, but this modification resulted in significantly
diminished inhibitory activity. We then explored the effects of
altering the amide group by preparing the amide derivatives
11-14, in which p-chlorobenzene, 2-naphthyl, furfuryl, or ethyl
pyridine rings attached Via an amide bond. Compounds 13 and
14, linked through one carbon and two carbon chain respec-
tively, demonstrated considerable potency in AGS cells, while
11 and 12 exhibited poor inhibition ability in both the cell lines.
The impact of modification to the B-ring carboxylic acid moiety
is of particular interest in the light of preliminary SAR results,
which suggests that a free acid or amide group at this position
is optimal for HIF-1 inhibition and that further derivatization
results in the significant loss of activity, except in the case of
analogues 9h,i, 13, and 14 which were as active as 1 in AGS
cells. Having established the primary structure-activity relation-
ship of rings A and B, we then introduced hydroxyl group para
to the amide in ring B, while retaining the adamantyl group on
ring A. This modification provided compounds 23 and 25, which
showed significantly enhanced inhibition of HIF-1 activity in
both the cell lines. On the other hand, although 26 and 29 were
active in AGS cells, compounds 27, 28, and 30 showed a marked
decrease in inhibitory activity.
a Reaction conditions: (a) (i) BnBr, K2CO3, acetone; (ii) NaOH, MeOH;
(b) (i) 2-(trimethylsilyl)ethanol, HBTU, DIPEA, DMF; (ii) Pd/C, H2, MeOH;
(c) 5a, oxalyl chloride, THF, DMF, and then 21 in pyridine for 23; 22,
HBTU, DIPEA, DMF, 50 °C for 24; (d) LiOH·H2O, dioxane, H2O; (e)
TBAF, DMF; (f) amine, trimethylaluminum, toluene, 80 °C for 26-28;
(g) EDCI, HOBT, DIPEA, DMF for 29; HATU, DIPEA, DMF for 30.
The newly synthesized compounds were evaluated for their
potential to inhibit HIF-1 activation induced by hypoxia (1%
O2, 94% N2, and 5% CO2) using a HIF-1-mediated cell-based
reporter assay in human hepatocellular carcinoma Hep3B and
human gastric adenocarcinoma AGS cell lines (Table 1 and 2).
All the assays were performed under standard assay conditions
by employing hypoxic condition and following the previously
described assay protocol.19 Cell viability, as measured by the
MTT assay, showed that most of the compounds had no
significant cytotoxicity at their effective concentrations for the
inhibition of HIF-1 activation (data not shown). YC-1,9b a known
small-molecule HIF-1 inhibitor, was used as a reference
compound for a comparison, which showed IC50 13.8 and 2.0
µM in Hep3B and AGS cells, respectively.
In order to define the key structural requirements for HIF-1
inhibition of aryloxyacetylaminobenzoic acid derivatives of 1,
our optimization strategy centered on two discrete areas: (1)
the aminophenyl ring B, which could be derivatized and (2)
the adamantyl phenyl ring A which could be replaced by a
phenyl ring containing various ring activating groups. In view
of the weak inhibitory activity of the ester 8a, we first examined
the significance of the carboxyl group on the N-phenyl ring B.
We synthesized the corresponding ortho and para isomers 2 and
3 (Figure 1), which were found to be less potent than the meta
To confirm their inhibition of HIF-1 activation, compounds
1, 10a, 23, and 25, which showed good inhibitory activity in
both cell lines, were evaluated by Western blot analysis for their

(Aryloxyacetylamino)benzoic Acid Analogues
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7 1677
Table 1. In Vitro Inhibition of HIF-1 Transcriptional Activity in
Table 2. Structure-Activity Relationships of Hydroxybenzoic Acid
Cell-Based HRE Reporter Assaya
Derivatives Based in Cell-Based HRE Reporter Assaya
a Values were obtained as described in the Supporting Information.
Figure 2. Western Blot analysis for the effect of compounds 1 (A),
10a (B), 23 (C) and 25 (D) on the accumulation of HIF-1R and HIF-
1â proteins in Hep3B cells under hypoxic condition. TOPO1 was used
as load control and V is DMSO as a control.
Figure 3. Time course effect of compound 23 on the accumulation of
HIF-1R in Hep3B cells under hypoxic condition.
time course data for the HIF-1R accumulation was determined
in the presence or absence of 30 µM of 23 under hypoxic
condition (Figure 3). The HIF-1R accumulation increased in a
time-dependent manner and reached its highest level at about
12 h incubation in the Hep3B cells. Conversely, HIF-1R
accumulation was inhibited by addition of 23 in a time-
dependent manner; however, TOPO1 expression was not
significantly inhibited by 16 h incubation, indicating that 23 is
not toxic at the concentration of 30 µM.
a Values were obtained as described in the Supporting Information.
effect on hypoxia-induced HIF-1R accumulation. As shown in
Figure 2, all four of these inhibitors blocked HIF-1R accumula-
tion in a dose-dependent manner without affecting the expression
level of HIF-1â protein. Of the four compounds, 23 was the
most potent inhibitor of HIF-1R accumulation. Accordingly,

1678 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7
Lee et al.
ness) unless otherwise indicated. Additionally, thin-layer chroma-
tography on 0.25 mm silica plates (E. Merck, silica gel 60 F254)
was used to monitor reactions. The chromatograms were visualized
using ultraviolet illumination, exposure to iodine vapors, dipping
in PMA, or Hanessian’s solution. The purity of the products was
checked by reversed phase high-pressure liquid chromatography
(RP-HPLC), which was performed either on Dionex Corp. HPLC
system or on Waters Corp. HPLC system equipped with a UV
detector set at 254 nm. The mobile phases used were A: H2O
containing 0.05% TFA, and B: CH3CN. The HPLC employed an
YMC Hydrosphere C18 (HS-302) column (5µ particle size, 12 nM
pore size), 4.6 mm diameter × 150 mm with a flow rate of 1.0
mL/min. The purity of compounds was assessed using the following
methods: Method A: gradient 20% B to 100% B in 30 min;
Method B: gradient 20% B to 100% B in 20 min; Method C:
gradient 40% B to 100% B in 30 min; Method D: gradient 50% B
to 100% B in 20 min; Method E: gradient 60% B to 100% B in
20 min. A table listing HPLC retention times and purities in two
different systems for 1, 8a, 9d-i, 10a-j, 11-18, 23, and 25-30
are shown in Supporting Information.
(4-Adamantan-1-yl-phenoxy)acetic Acid (5a). A suspension of
4-(1-adamantyl)phenol 4a (2.0 g, 8.76 mmol), anhydrous potassium
carbonate (3.63 g, 26.29 mmol), and ethyl chloroacetate (1.289 g,
10.51 mmol) in DMF (10 mL) was stirred overnight at room
temperature. Reaction mixture was diluted with EtOAc and
sequentially washed with aqueous sodium bicarbonate, brine, and
water and dried over anhydrous MgSO4. The solvent was filtered
and evaporated under reduced pressure to afford a crude solid, which
was purified by column chromatography on silica gel (EtOAc:n-
hexane ) 1:9 to 1:3) to afford (4-adamantan-1-yl-phenoxy)acetic
acid ethyl ester as a colorless solid (2.62 g, 94.6% yield). Rf )
0.29 (EtOAc:n-hexane ) 1:9); mp 86.6-88.6 °C; 1H NMR (CDCl3,
300 MHz) δ 7.28 (2H, m, aromatic-H), 6.86 (2H, m, aromatic-H),
4.60 (2H, s, OCH2CO), 4.27 (2H, q, J ) 7.2 Hz, OCH2CH3), 2.08
(3H, brs, adamantyl-H), 1.88 (6H, d, J ) 3.0 Hz, adamantyl-H),
1.76 (6H, m, adamantyl-H), 1.30 (3H, t, J ) 6.9 Hz, OCH2CH3);
MS (ESI) m/z 337 (M + Na)+. To a mixture of (4-adamantan-1-
yl-phenoxy)-acetic acid ethyl ester (1.1 g, 3.50 mmol) in THF/
H2O (1:1, 20 mL) was added lithium hydroxide monohydrate (0.29
g, 7.00 mmol) and stirred overnight at room temperature. Reaction
mixture was neutralized with 10% HCl, diluted with EtOAc,
sequentially washed with aqueous sodium bicarbonate, brine, and
water, and dried over anhydrous MgSO4. The solvent was filtered
and evaporated under reduced pressure to afford a crude solid, which
was purified by column chromatography on silica gel column
chromatography (CH2Cl2:MeOH ) 30:1) to give (4-adamantan-1-
yl-phenoxy)acetic acid as a white solid (0.61 g, 61.3% yield). Rf )
0.16 (CH2Cl2:MeOH ) 15:1); 1H NMR (CD3OD, 300 MHz) δ 7.26
(2H, m, aromatic-H), 6.85 (2H, m, aromatic-H), 4.59 (2H, s, OCH2-
CO), 2.05 (3H, m, adamantyl-H), 1.89 (6H, m, adamantyl-H), 1.75-
1.84 (6H, m, adamantyl-H).
Figure 4. RT PCR analysis for the effect of compounds 1 (A) and 23
(B) on the hypoxia-induced mRNA expression of VEGF and EPO in
Hep3B cells. GAPDH was used as load control and V is DMSO as
control.
To confirm that inhibition of HIF-1R results in decreased
expression of its target genes, compounds 1 and 23 were
analyzed by RT-PCR analysis for their effect on the mRNA
expression of two well-known HIF-1 target genes VEGF and
EPO, both of which are associated with the aggressive tumor
phenotype.20 The hypoxia-induced mRNA expression of VEGF
and EPO was suppressed dose-dependently by 1 or 23 without
any affect on the mRNA expression level of HIF-1R and
GAPDH (Figure 3) in Hep3B cells. Of particular interest,
compound 23 significantly suppressed the hypoxia-induced
mRNA expression of VEGF and EPO at a concentration of
10µM.
On the basis of this preliminary SAR, involving structural
modification, we have defined the structural requirements for
the HIF-1 inhibition of aryloxyacetylaminobenzoic acid ana-
logues and identified several highly potent HIF-1 inhibitors.
Some of these inhibitors, including compound 23, were further
evaluated for their inhibitory effect on the HIF-1R protein
accumulation and mRNA expression of the target genes under
hypoxic conditions. HIF-1 is known to play an important role
in solid tumors, and although the detailed mechanism of its
inhibition is still unclear, the compounds described in this study
could serve as valuable leads for chemotherapeutic intervention
in HIF-1-mediated tumor progression and angiogenesis.
Experimental Section
General. All of the commercial chemicals and solvents are of
reagent grade and were used without further purification. 3-(2-
Phenoxyacetamido)benzoic acid (9b), 3-(2-(p-tolyloxy)acetamido)-
benzoic acid (9c), 3-aminobenzoic acid methyl ester (6), 3-ami-
nobenzamide (7), 4-hydroxy-3-nitrobenzoic acid (19), 3-amino-4-
hydroxy-benzoic acid methyl ester (21), tetrakis(triphenylphosphine)-
palladium [Pd(PPh3)4], O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tet-
ramethyluronium hexafluorophosphate (HATU), diisopropylethyl-
amine (DIPEA), O-(benzotriazol-1-yl)- N,N,N′,N′-tetramethyluro-
nium hexafluorophosphate (HBTU), 1-hydroxybenzotriazole (HOBT),
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), and 1-n-
butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) were
purchased from commercial sources. All reactions were carried out
under an atmosphere of dried argon in flame-dried glassware.
Melting points were determined in open capillary tubes on an
Electrothermal apparatus and are uncorrected. Proton nuclear
magnetic resonance (1H NMR) spectra were determined on a Varian
(300 MHz) spectrometer. Chemical shifts are provided in parts per
million (ppm) downfield from tetramethylsilane (internal standard)
with coupling constants in hertz (Hz). Multiplicity is indicated by
the following abbreviations: singlet (s), doublet (d), doublet of
doublet (dd), triplet (t), pseudo triplet (ps-t), quartet (q), multiplet
(m), broad (br). Mass spectra were recorded on a Finnigan ESI
mass spectrometer, and HRMS (ESI-MS) was obtained on a
Mariner instrument (Perseptive Biosystem). Products from all
reactions were purified to a minimum purity of 96% as determined
by HPLC, either by flash column chromatography using silica gel
60 (230-400 mesh Kieselgel 60) or by preparative thin layer
chromatography using glass-backed silica gel plates (1 mm thick-
4-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-benzoic Acid
(1). EDCI (144.0 mg, 0.75 mmol) and HOBT (101 mg, 0.75 mmol)
were added to a solution of (4-adamantan-1-yl-phenoxy)acetic acid
(5a, 140 mg, 0.5 mmol), 3-aminobenzoic acid methyl ester (6, 110
mg, 0.75 mmol), and DIPEA (0.13 mL, 0.75 mmol) in DMF (5.0
mL), and the mixture was stirred overnight at room temperature. It
was then partitioned between EtOAc and brine, and the organic
layer was separated and concentrated under reduced pressure. The
resulting residue was purified by silica gel column chromatography
(n-hexane:EtOAc:MeOH ) 15:3:1) to give 4-[2-(4-adamantan-1-
yl-phenoxy)-acetylamino]benzoic acid methyl ester (8a) as a white
solid (160 mg, 76% yield). Rf ) 0.48 (n-hexane:EtOAc:MeOH )
1
15:3:1); mp 184.5 °C; H NMR (DMSO-d6, 300 MHz) δ 10.31
(1H, s, NH), 8.34 (1H, m, aromatic-H), 7.89 (1H, m, aromatic-H),
7.67 (1H, m, aromatic-H), 7.47 (1H, ps-t, J ) 7.8 Hz, aromatic-
H), 7.28 (2H, m, aromatic-H), 6.93 (2H, m, aromatic-H), 4.68 (2H,
s, OCH2CO), 3.85 (3H, s, OCH3), 2.03 (3H, m, adamantyl-H),
1.81-1.82 (6H, m, adamantyl-H), 1.71 (6H, m, adamantyl-H); MS
(ESI) m/z 420 (M + H)+, 418 (M - H)-; HRMS (ESI) m/z calcd
for C26H33N2O4 [(M + NH4)+] 437.2435, found: 437.2434). A

(Aryloxyacetylamino)benzoic Acid Analogues
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7 1679
mixture of 8a (306 mg, 0.72 mmol) and lithium hydroxide
monohydrate (60 mg, 1.44 mmol) in THF/H2O/1,4-dioxane (1:1:
1, 300 mL) was stirred overnight at room temperature, acidified to
pH 7 with 10% HCl, and diluted with EtOAc. The organic layer
was separated and concentrated under reduced pressure, and the
resulting residue was purified by silica gel column chromatography
(n-hexane:EtOAc:MeOH ) 15:3:1) to give 1, as a white solid (152
mg, 43% yield). Rf ) 0.45 (n-hexane:EtOAc:MeOH ) 6:3:1); mp
223-224 °C; 1H NMR (DMSO-d6, 300 MHz) δ 10.21 (1H, s, NH),
8.21 (1H, s, aromatic-H), 7.79 (1H, d, J ) 8.7 Hz, aromatic-H),
7.64 (1H, d, J ) 7.2 Hz, aromatic-H), 7.30 (3H, m, aromatic-H),
6.93 (2H, m, aromatic-H), 4.67 (2H, s, OCH2CO), 2.03 (3H, m,
adamantyl-H), 1.82-1.83 (6H, m, adamantyl-H), 1.71 (6H, m,
adamantyl-H); MS (ESI) m/z 428 (M + Na)+, 404 (M - H)-;
HRMS (ESI) m/z calcd for C25H27NO4Na [(M + Na)+] 428.1832,
found: 428.1822.
noxy)-acetylamino]-benzoic acid 3: a white solid (40.7 mg, 53.1%
yield). Rf ) 0.45 (n-hexane:EtOAc:MeOH ) 6:3:1); 1H NMR
(DMSO-d6, 300 MHz) δ 10.34 (1H, s, NH), 7.89 (2H, d, J ) 8.4
Hz, aromatic-H), 7.73 (2H, d, J ) 8.7 Hz, aromatic-H), 7.27-7.30
(2H, m, aromatic-H), 6.90-6.93 (2H, m, aromatic-H), 4.69 (2H, s,
CH2), 2.04 (3H, m, adamantyl-H), 1.82 (6H, m, adamantyl-H), 1.72
(6H, m, adamantyl-H); MS (ESI) m/z 428 (M + Na)+, 404 (M -
H)-; Purity >99% (as determined by RP-HPLC, method A, tR )
14.9 min).
General Procedure for the Preparation of 8d-i. EDCI (1.5-
2.0 equiv) and HOBt (1.5-2.0 equiv) were added to a solution of
appropriate phenoxyacetic acid 5d-i (1.0 equiv), 3-aminobenzoic
acid methyl ester 6 (1.5-2.0 equiv), and DIPEA (1.5-2.0 equiv)
in DMF, and the reaction mixture was stirred at room temperature
until completion as monitored by TLC. The reaction mixture was
diluted with EtOAc or with a mixture of MeOH/CH2Cl2 (10%) and
10% HCl, and the organic layer was separated, sequentially washed
with brine, aqueous sodium bicarbonate, and water, and dried over
anhydrous MgSO4. The solvent was filtered and evaporated under
reduced pressure to afford a crude solid, which was purified by
silica gel column chromatography.
2-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-benzoic Acid
(2). To a mixture of (4-adamantan-1-yl-phenoxy)acetic acid (5a,
85.9 mg, 0.30 mmol), 2-aminobenzoic acid methyl ester (0.07 mL,
0.54 mmol), EDCI (103.5 mg, 0.54 mmol), and HOBt (73.0 mg,
0.54 mmol) in DMF (3.6 mL) was added DIPEA (69.8 mg, 0.10
mL, 0.54 mmol), and it was stirred overnight at room temperature.
The mixture was then partitioned between EtOAc and 10% HCl.
The organic layer was separated, washed with brine, dried over
anhydrous MgSO4, filtered, and concentrated under vacuo. The
residue was purified by silica gel flash column chromatography
(n-hexane:EtOAc:MeOH ) 12:3:1) to give 2-[2-(4-adamantan-1-
yl-phenoxy)-acetylamino]-benzoic acid methyl ester as a white solid
(46.4 mg, 36.9% yield). Rf ) 0.72 (n-hexane:EtOAc:MeOH ) 12:
3-[2-(4-tert-Butyl-phenoxy)-acetylamino-benzoic Acid Methyl
Ester (8d). Obtained as a yellowish solid (185 mg, quantitative
yield) from 5d. Rf ) 0.57 (n-hexane:EtOAc:MeOH ) 9:3:1); mp
1
76.6-77.8 °C; H NMR (CDCl3, 300 MHz) δ 8.40 (1H, s, NH),
7.99-8.08 (2H, m, aromatic-H), 7.82-7.84 (1H, m, aromatic-H),
7.45 (1H, ps-t, J ) 7.8 Hz, aromatic-H), 7.34-7.38 (2H, m,
aromatic-H), 6.9-6.96 (2H, m, aromatic-H), 4.61 (2H, s, CH2),
3.93 (3H, s, CH3), 1.32 (9H, s, CH3); MS (ESI) m/z 364 (M +
Na)+, 340 (M - H)-; Purity >99% (as determined by RP-HPLC,
method B, tR ) 17.6 min).
1
3:1); H NMR (CDCl3, 300 MHz) δ 12.1 (1H, s, NH), 8.79 (1H,
d, J ) 8.7 Hz, aromatic-H), 8.05 (1H, dd, J ) 7.8, 1.8 Hz, aromatic-
H), 7.54-7.60 (1H, m, aromatic-H), 7.31-7.35 (2H, m, aromatic-
H), 7.12-7.16 (2H, m, aromatic-H), 7.03-7.07 (2H, m, aromatic-
H), 4.62 (2H, s, CH2), 3.93 (3H, s, CH3), 2.08 (3H, m, adamantyl-
H), 1.88 (6H, m, adamantyl-H), 1.70-1.80 (6H, m, adamantyl-H);
MS (ESI) m/z 442 (M + Na)+, 418 (M - H)-; Purity >99% (as
determined by RP-HPLC, method A, tR ) 23.7 min). A solution
of 2-[2-(4-adamantan-1-yl-phenoxy)-acetylamino]-benzoic acid meth-
yl ester (30.5 mg, 0.07 mmol) in 1,4-dioxane/H2O (3:1, 3 mL) was
treated with lithium hydroxide monohydrate (8.4 mg, 0.2 mmol)
and stirred at room temperature until the reaction was complete as
judged by TLC. The reaction mixture was then acidified with 10%
HCl to pH 7 and then partitioned between EtOAc and brine. The
organic layer was separated, washed with water, dried over
anhydrous MgSO4, filtered, and concentrated under vacuo. The
residue was purified by silica gel flash column chromatography
(n-hexane:EtOAc:MeOH ) 6:3:1) to give 2-[2-(4-adamantan-1-yl-
phenoxy)-acetylamino]-benzoic acid as a white solid (18.5 mg,
3-[2-(4-Acetyl-phenoxy)-acetylamino]-benzoic Acid Methyl
Ester (8e). Obtained as a white solid (158 mg, 97% yield) from
5e. Rf ) 0.40 (n-hexane:EtOAc:MeOH ) 6:3:1); mp 130.2-130.9
°C; 1H NMR (CDCl3, 300 MHz) δ 8.32 (1H, s, NH), 8.07 (1H, m,
aromatic-H), 7.97-8.01 (3H, m, aromatic-H), 7.83 (1H, d, J ) 7.8
Hz, aromatic-H), 7.45 (1H, ps-t, J ) 7.8 Hz, aromatic-H), 7.05
(2H, m, aromatic-H), 4.69 (2H, s, OCH2CO), 3.92 (3H, s, OCH3),
2.58 (3H, s, COCH3); MS (ESI) m/z 350 (M + Na)+, 326 (M -
H)-; Purity > 99% (as determined by RP-HPLC, method A, tR )
13.5 min).
3-[2-(4-Fluoro-phenoxy)-acetylamino]-benzoic Acid Methyl
Ester (8f). Obtained as a white solid (236.1 mg, 88.5% yield) from
5f. Rf ) 0.49 (n-hexane:EtOAc:MeOH ) 6:3:1); mp 102.6-103.3
°C; 1H NMR (CDCl3, 300 MHz) δ 8.37 (1H, s, NH), 8.07 (1H, m,
aromatic-H), 7.99-8.02 (1H, m, aromatic-H), 7.83 (1H, d, J ) 7.8
Hz, aromatic-H), 7.44 (1H, ps-t, J ) 7.8 Hz, aromatic-H), 7.02-
7.08 (2H, m, aromatic-H), 6.93-6.97 (2H, m, aromatic-H), 4.59
(2H, s, CH2), 3.92 (3H, s, CH3); MS (ESI) m/z 326 (M + Na)+,
302 (M - H)-; purity > 99% (as determined by RP-HPLC, method
C, tR ) 10.8 min).
3-[2-(4-Chloro-phenoxy)-acetylamino]-benzoic Acid Methyl
Ester (8g). Obtained as a white solid (135.2 mg, 84.5% yield) from
5g. Rf ) 0.61 (n-hexane:EtOAc:MeOH ) 6:3:1); mp 105.3-106.1
°C; 1H NMR (CDCl3, 300 MHz) δ 8.32 (1H, s, NH), 8.06 (1H, s,
aromatic-H), 8.00 (1H, d, J ) 8.4 Hz, aromatic-H), 7.83 (1H, d, J
) 7.2 Hz, aromatic-H), 7.45 (1H, ps-t, J ) 7.8 Hz, aromatic-H),
7.29-7.34 (2H, m, aromatic-H), 6.91-6.97 (2H, m, aromatic-H),
4.60 (2H, s, CH2), 3.92 (3H, s, CH3); MS (ESI) m/z 342 (M +
Na)+, 318 (M - H)-; HPLC > 99% (as determined by RP-HPLC,
method A, tR ) 16.4 min).
3-[2-(4-Bromo-phenoxy)-acetylamino]-benzoic Acid Methyl
Ester (8h). Obtained as a white solid (138 mg, 76% yield) from
5h. Rf ) 0.73 (n-hexane:EtOAc:MeOH ) 6:3:1); mp 109.1-109.6
°C; 1H NMR (CDCl3, 300 MHz) δ 8.32 (1H, s, NH), 8.06 (1H, m,
aromatic-H), 7.99 (1H, m, aromatic-H), 7.84 (1H, m, aromatic-H),
7.42-7.47 (3H, m, aromatic-H), 6.89 (2H, m, aromatic-H), 4.59
(2H, s, OCH2CO), 3.92 (3H, s, OCH3); MS (ESI) m/z 386 (M +
Na)+, 362 (M - H)-; Purity >96% (as determined by RP-HPLC,
method D, tR ) 9.52 min).
1
62.5% yield). Rf ) 0.29 (n-hexane:EtOAc:MeOH ) 6:3:1); H
NMR (DMSO-d6, 300 MHz) δ 8.57 (1H, d, J ) 8.4 Hz, aromatic-
H), 8.01-8.04 (1H, m, aromatic-H), 7.32-7.37 (1H, m, aromatic-
H), 7.26 (2H, d, J ) 8.4 Hz, aromatic-H), 7.00-7.05 (3H, m,
aromatic-H), 4.58 (2H, s, CH2), 2.03 (3H, m, adamantyl-H), 1.81
(6H, m, adamantyl-H), 1.71 (6H, m, adamantyl-H); MS (ESI) m/z
428 (M + Na)+, 404 (M - H)-; Purity >99% (as determined by
RP-HPLC, method A, tR ) 17.0 min).
4-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-benzoic Acid
(3). Compound 3 was prepared from 5a and 4-aminobenzoic acid
methyl ester on a 0.5 mmol scale by the same procedure for
compound 2. Purification by silica gel flash column chromatography
(n-hexane:EtOAc:MeOH ) 6:3:1) for 4-[2-(4-adamantan-1-yl-
phenoxy)-acetylamino]-benzoic acid methyl ester: a white solid
(108.3 mg, 51.7% yield). Rf )0.48 (n-hexane:EtoAc:MeOH )12:
1
3:1); H NMR (CDCl3, 300 MHz) δ 8.46 (1H, s, NH), 8.04 (2H,
d, J ) 21.3 Hz, aromatic-H), 7.69 (2H, d, J ) 9.3 Hz, aromatic-
H), 7.34 (2H, d, J ) 8.7 Hz, aromatic-H), 6.94 (2H, d, J ) 8.7 Hz,
aromatic-H), 4.61 (2H, s, CH2), 3.90 (3H, s, CH3), 1.75-2.09 (15H,
m, adamantyl- H); MS (ESI) m/z 420 (M + H)+, 418 (M - H)-;
Purity >99% (as determined by RP-HPLC, method A, tR ) 14.9
min). Purification by silica gel flash column chromatography (n-
hexane:EtOAc:MeOH ) 6:3:1) for 4-[2-(4-adamantan-1-yl-phe-

1680 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7
Lee et al.
3-[2-(4-Iodo-phenoxy)-acetylamino]-benzoic Acid Methyl Es-
ter (8i). Obtained as a white solid (199.0 mg, 97% yield) from 5i.
Rf ) 0.66 (n-hexane:EtOAc:MeOH ) 6:3:1); mp 102.6-103.3 °C;
1H NMR (CDCl3, 300 MHz) δ 8.31 (1H, s, NH), 8.06 (1H, s,
aromatic-H), 8.00 (1H, d, J ) 8.1 Hz, aromatic-H), 7.83 (1H, d, J
) 7.8 Hz, aromatic-H), 7.61-7.66 (2H, m, aromatic-H), 7.44 (1H,
ps-t, J ) 7.8 Hz, aromatic-H), 6.76-6.81 (2H, m, aromatic-H),
4.59 (2H, s, CH2), 3.92 (3H, s, CH3); MS (ESI) m/z 434 (M +
Na)+, 410 (M - H)-; Purity >99% (as determined by RP-HPLC,
method D, tR ) 14.5 min).
General Procedure for the Preparation of 9d-i. A mixture
of appropriate (4-substituted phenoxy)-acetylamino benzoic acid
methyl ester 8d-i (1.0 mmol) and lithium hydroxide monohydrate
(2.0 mmol) in THF/H2O (1:1, 12 mL) was stirred at room
temperature until completion, as monitored by TLC. Then the
mixture was acidified with 10% HCl to pH 7 and partitioned
between EtOAc and brine. The organic layer was separated washed
with water, dried over anhydrous MgSO4, filtered, and concentrated
in vacuo. The residue was purified by silica gel flash column
chromatography.
zamide 7 (1.5-2.0 equiv), and DIPEA (1.5-2.0 equiv) in DMF,
and the resulting mixture was stirred at room temperature until
completion as monitored by TLC. Reaction mixture was diluted
with EtOAc or with a mixture of MeOH/CH2Cl2 (10%), sequentially
washed with aqueous sodium bicarbonate, brine, and water, and
dried over anhydrous MgSO4. The solvent was filtered and
evaporated under reduced pressure to afford a crude solid, which
was purified by silica gel column chromatography (MeOH:CH2-
Cl2 ) 1:9 to 3:9).
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-benzamide
(10a). Obtained as a colorless solid (145.0 mg, 89.6% yield) from
5a. Rf ) 0.32 (n-hexane:EtOAc:MeOH ) 12:3:1); mp 150.6-151.4
1
°C; H NMR (CD3OD, 300 MHz) δ 8.08 (1H, m, aromatic-H),
7.80 (1H, m, aromatic-H), 8.57 (1H, d, J ) 8.4 Hz, aromatic-H),
7.43 (1H, m, aromatic-H), 7.30 - 7.33 (2H, m, aromatic-H), 7.00
(2H, m, aromatic-H), 4.65 (2H, s, CH2), 2.06 (3H, m, adamantyl-
H), 1.90 (6H, m, adamantyl-H), 1.80 (6H, m, adamantyl-H); MS
(ESI) m/z 427 (M + Na)+, 403 (M - H)-; HRMS (ESI) m/z calcd
for C25H32O3N3 [(M + NH4)+] 422.2438, found: 422.2449.
3-(2-Phenoxy-acetylamino)-benzamide (10b). Obtained as a
colorless solid (146 mg, 82.2% yield) from 5b. Rf ) 0.62 (MeOH:
MC ) 1:9); mp 180.4-182.3 °C; 1H NMR (DMSO-d6, 300 MHz)
δ 10.19 (1H, s, CONH), 8.09 (1H, s, aromatic-H), 7.93 (1H, s,
CONH2), 7.80 (1H, m, aromatic-H), 7.56 (1H, d, J ) 7.5 Hz,
aromatic-H), 7.35 (4H, m, aromatic-H, CONH2), 6.98 (3H, m,
aromatic-H), 4.70 (2H, s, OCH2); MS (ESI) m/z 293 (M + Na)+,
269 (M - H)-; HRMS (ESI) m/z calcd for C15H15N2O3 [(M +
H)+] 271.1077, found: 271.1084.
3-[2-(4-tert-Butyl-phenoxy)-acetylamino-benzoic Acid (9d).
Obtained as a white solid (68.7 mg, 65.7% yield) from the
1
corresponding ester 8d. Rf ) 0.35 (CH2Cl2:MeOH ) 10:1); H
NMR (CDCl3, 300 MHz) δ 8.41 (1H, s, NH), 8.03-8.11 (2H, m,
aromatic-H), 7.87 (1H, d, J ) 7.5 Hz, aromatic-H), 7.45 (1H, m,
aromatic-H), 7.36 (2H, d, J ) 8.7 Hz, aromatic-H), 6.92 (2H, m,
aromatic-H), 4.60 (2H, s, CH2), 1.31 (9H, s, CH3); MS (ESI) m/z
350 (M + Na)+, 326 (M - H)-; HRMS (ESI) m/z calcd for
C19H21O4NNa [(M + Na)+] 350.1363, found: 350.1397).
3-(2-p-Tolyloxy-acetylamino)-benzamide (10c). Obtained as a
colorless solid (133 mg, 77.8% yield) from 5c. Rf ) 0.56 (MeOH:
MC ) 1:9); mp 187-189.1 °C; 1H NMR (DMSO-d6, 300 MHz) δ
10.16 (1H, s, CONH), 8.09 (1H, s, aromatic-H), 7.93 (1H, s,
CONH2), 7.80 (1H, d, J ) 8.1 Hz, aromatic-H), 7.56 (1H, d, J )
8.1 Hz, aromatic-H), 7.37 (2H, m, aromatic-H, CONH2), 7.10 (2H,
d, J ) 8.7 Hz, aromatic-H), 6.9 (2H, d, J ) 8.4 Hz, aromatic-H),
4.65 (2H, s, OCH2), 2.23 (3H, s, CH3); MS (ESI) m/z 307 (M +
Na)+, 283 (M - H)-; HRMS (ESI) m/z calcd for C16H20N3O3 [(M
+ NH4)+] 302.1499, found: 302.1502.
3-[2-(4-Acetyl-phenoxy)-acetylamino]-benzoic Acid (9e). Ob-
tained as a white solid (73 mg, 67% yield) from the corresponding
ester 8e. Rf ) 0.41 (CH2Cl2:MeOH ) 15:1); mp 199.4-201.0 °C
1
(dec); H NMR (CD3OD, 300 MHz) δ 8.26 (1H, m, aromatic-H),
8.00 (2H, m, aromatic-H), 7.86 (1H, m, aromatic-H), 7.79 (1H, d,
J ) 8.1 Hz, aromatic-H), 7.43 (1H, ps-t, J ) 8.1 Hz, aromatic-H),
7.14 (2H, m, aromatic-H), 4.79 (2H, s, OCH2CO), 2.55 (3H, s,
COCH3); MS (ESI) m/z 336 (M + Na)+, 312 (M - H)-.
3-[2-(4-Fluoro-phenoxy)-acetylamino]-benzoic Acid (9f). Ob-
tained as a white solid (108.3 mg, 83.24% yield) from the
corresponding ester 8f. Rf ) 0.18 (n-hexane:EtOAc:MeOH ) 6:3:
1); 1H NMR (DMSO-d6, 300 MHz) δ 10.31 (1H, s, NH), 8.27 (1H,
s, aromatic-H), 7.84 (1H, d, J ) 8.7 Hz, aromatic-H), 7.67 (1H, d,
J ) 8.1 Hz, aromatic-H), 7.41 (1H, ps-t, J ) 7.8 Hz, aromatic-H),
7.12-7.18 (2H, m, aromatic-H), 7.01-7.05 (2H, m, aromatic-H),
4.71 (2H, s, CH2); MS (ESI) m/z 312 (M + Na)+, 288 (M - H)-.
3-[2-(4-Chloro-phenoxy)-acetylamino]-benzoic Acid (9g). Ob-
tained as a white solid (70.3 mg, 74.2% yield) from the corre-
sponding ester 8g. Rf ) 0.28 (n-hexane:EtOAc:MeOH ) 6:3:1);
1H NMR (DMSO-d6, 300 MHz) δ 10.30 (1H, s, NH), 8.26 (1H, s,
aromatic-H), 7.83 (1H, d, J ) 7.8 Hz, aromatic-H), 7.66 (1H, d, J
) 7.2 Hz, aromatic-H), 7.44 (1H, ps-t, J ) 7.8 Hz, aromatic-H),
7.33-7.36 (2H, m, aromatic-H), 7.01-7.04 (2H, m, aromatic-H),
4.72 (2H, s, CH2); MS (ESI) m/z 328 (M + Na)+, 304 (M - H)-).
3-[2-(4-Bromo-phenoxy)-acetylamino]-benzoic Acid (9h). Ob-
tained as a white solid (44.6 mg, 51% yield) from the corresponding
ester 8h. Rf ) 0.22 (n-hexane:EtOAc:MeOH ) 6:3:1); mp 226.0-
226.9 °C; 1H NMR (CD3OD, 300 MHz) δ 8.26 (1H, m, aromatic-
H), 7.86 (1H, m, aromatic-H), 7.79 (1H, d, J ) 8.1 Hz, aromatic-
H), 7.41-7.46 (3H, m, aromatic-H), 6.99 (2H, m, aromatic-H), 4.68
(2H, s, OCH2CO); MS (ESI) m/z 372 (M + Na)+, 348 (M - H)-.
3-[2-(4-Iodo-phenoxy)-acetylamino]-benzoic Acid (9i). Ob-
tained as a white solid (64.4 mg, 67.7% yield) from the corre-
sponding ester 8i. Rf ) 0.16 (n-hexane:EtOAc:MeOH ) 6:3:1);
1H NMR (DMSO-d6, 300 MHz) δ 8.25 (1H, s, aromatic-H), 7.85
(1H, d, J ) 8.1 Hz, aromatic-H), 7.60-7.67 (3H, m, aromatic-H),
7.43 (1H, ps-t, J ) 8.1 Hz, aromatic-H), 6.86 (2H, d, J ) 8.7 Hz,
aromatic-H), 4.72 (2H, s, CH2); MS (ESI) m/z 420 (M + Na)+,
396 (M - H)-.
3-[2-(4-tert-butyl-Phenoxy)-acetylamino]-benzamide (10d). Ob-
tained as a colorless solid (168 mg, 85.8% yield) from 5d. Rf )
1
0.55 (MeOH:MC ) 1:9); mp 187-190 °C; H NMR (DMSO-d6,
300 MHz) δ 10.18 (1H, s, CONH), 8.10 (1H, s, aromatic-H), 7.93
(1H, s, CONH2), 7.80 (1H, d, J ) 8.1 Hz, aromatic-H), 7.56 (1H,
d, J ) 8.1 Hz, aromatic-H), 7.35 (4H, m, aromatic-H, CONH2),
6.92 (2H, dd, J ) 3.0, 12.3 Hz, aromatic-H), 4.67 (2H, s, OCH2),
1.25 (9H, s, C(CH3)3); MS (ESI) m/ z 349 (M + Na)+, 325 (M -
H)-.
3-[2-(4-Nitro-phenoxy)-acetylamino]-benzamide (10j). Ob-
tained as a colorless solid (135 mg, 81% yield) from 5j. Rf ) 0.52
1
(MeOH:MC ) 1:9); mp 205.1-207.4 °C; H NMR (CDCl3, 300
MHz) δ10.32 (1H, s, CONH), 8.24 (2H, d, J ) 9.3 Hz, aromatic-
H), 8.08 (1H, s, aromatic-H), 7.94 (1H, s, CONH2), 7.78 (1H, d, J
) 8.1 Hz, aromatic-H), 7.58 (1H, d, J ) 7.2 Hz, aromatic-H), 7.39
(2H, m, aromatic-H, CONH2), 7.21 (2H, d, J ) 9.3 Hz, aromatic-
H), 4.92 (2H, s, OCH2); MS (ESI) m/z 338 (M + Na)+, 314 (M -
H)-; HRMS (ESI) m/z calcd for C15H17N4O5 [(M + NH4)+]
333.1193, found: 333.1166.
General Procedure for the Preparation of 11-14. EDCI (1.5
equiv) and HOBt (1.5 equiv) were added to a solution of 4-[2-(4-
adamantan-1-yl-phenoxyl)-acetylamino]-benzoic acid 1 (1.0 equiv),
appropriate amine (1.5 equiv), and DIPEA (1.5 equiv) in DMF (5
mL), and the resulting mixture was stirred at room temperature
until completion as monitored by TLC. Reaction mixture was
diluted with EtOAc, sequentially washed with aqueous sodium
bicarbonate, brine, and water, and dried over anhydrous MgSO4.
The solvent was filtered and evaporated under reduced pressure to
afford a crude solid, which was purified either by silica gel column
chromatography or by preparative TLC.
General Procedure for the Preparation of 10a-d,j. EDCI
(1.5-2.0 equiv) and HOBt (1.5-2.0 equiv) were added to a solution
of appropriate phenoxyacetic acid 5a-d,j (1.0 equiv), 3-aminoben-
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-N-(4-chloro-
phenyl)-benza mide (11). Obtained as a colorless solid (15 mg,
59% yield). Rf ) 0.29 (EtOAc:n-hexane ) 3:7); mp 247-250 °C;

(Aryloxyacetylamino)benzoic Acid Analogues
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7 1681
1H NMR (DMSO-d6, 300 MHz) δ 10.39 (1H, s, CONH), 10.27
(1H, s, CONH), 8.16 (1H, s, aromatic-H), 7.89 (1H, d, J ) 8.7 Hz,
aromatic-H), 7.80 (2H, d, J ) 9.0 Hz, aromatic-H), 7.66 (1H, d, J
) 7.8 Hz, aromatic-H), 7.45 (3H, m, aromatic-H), 7.28 (2H, d, J
) 8.4 Hz, aromatic-H), 6.93 (2H, d, J ) 8.4 Hz, aromatic-H), 4.69
(2H, s, OCH2CO), 2.03 (3H, s, adamantyl-H), 1.83 (6H, s,
adamantyl-H), 1.71 (6H, s, adamantyl-H); MS (ESI) m/z 513 (M
- H)-; HRMS (ESI) m/z calcd for C31H35N3O3Cl [(M + NH4)+]
532.2361, found: 532.2372.
(dec); 1H NMR (DMSO-d6, 300 MHz) δ 8.38 (1H, s, aromatic-H),
8.29 (1H, s, aromatic-H), 8.10 (2H, m, aromatic-H), 7.86 (1H, d,
J ) 7.8 Hz, aromatic-H), 7.65-7.76 (4H, m, aromatic-H), 7.44
(1H, ps-t, J ) 7.8 Hz, aromatic-H), 7.14 (2H, m, aromatic-H), 4.79
(2H, s, OCH2CO); MS (ESI) m/z 391 (M - H)-; HRMS (ESI) m/z
calcd for C21H20N3O6 [(M + NH4)+] 410.1346, found: 410.1355.
3-[2-(4-Thiophen-2-yl-phenoxy)-acetylamino]-benzoic Acid
(16). To a mixture of 3-[2-(3′-bromo-phenoxy)-acetylamino]-
benzoic acid methyl ester 8h (100 mg, 0.27 mmol) and Pd(PPh3)4
(16.2 mg, 0.014 mmol) in 1,2-dimethoxyethane (7.0 mL) was added
thiophene-2-boronic acid (23.2 mg, 0.19 mmol) followed by the
addition of sodium hydrogen carbonate (42.85 mg, 0.51 mmol) in
H2O (0.68 mL). The reaction mixture was refluxed with vigorous
stirring until completion as monitored by TLC. The organic solvent
was removed under reduced pressure and then partitioned between
EtOAc and brine. The organic layer was separated, dried over
anhydrous MgSO4, filtered, and concentrated under reduced pres-
sure. Purification by silica gel column chromatography (CH2Cl2:
MeOH ) 5:1) gave 3-[2-(4-thiophen-2-yl-phenoxy)-acetylamino]-
benzoic acid as a white solid (19.8 mg, 33% yield). Rf ) 0.25
(CH2Cl2:MeOH ) 10:1); 1H NMR (DMSO-d6, 300 MHz) δ 10.31
(1H, s, NH), 8.23 (1H, s, aromatic-H), 7.85 (1H, d, J ) 8.1 Hz,
aromatic-H), 7.59-7.67 (3H, m, aromatic-H), 7.38-7.47 (3H, m,
aromatic-H), 7.04-7.11 (3H, m, aromatic-H), 4.76 (2H, s, CH2);
MS (ESI) m/z 376 (M + Na)+, 352 (M - H)-; HRMS (ESI) m/z
calcd for C19H15NO4S [(M + NH4)+] 354.07946, found: 354.08151.
3-[2-(4′-Methyl-biphenyl-4-yloxy)- acetylamino]-benzoic acid
(17). 3-[2-(3′-Bromo-phenoxy)-acetylamino]-benzoic acid methyl
ester 8h (150 mg, 0.41 mmol) was added to a suspension of Pd-
(PPh3)4 (23.8 mg, 0.021 mmol) in degassed [bmim][BF4] (0.5 mL)
at ambient temperature. The mixture was stirred overnight at 110
°C. The solution was cooled to ambient temperature and sequentially
added 4-tolyl boronic acid (112 mg, 0.82 mmol) and a solution of
sodium hydrogen carbonate (68.9 mg, 0.82 mmol) in water (1.0
mL). The mixture was reheated overnight at 110 °C with vigorous
stirring and then cooled and extracted with EtOAc. The combined
extracts were washed with brine and water, dried over anhydrous
MgSO4, and concentrated under vacuo. Purification by silica gel
column chromatography (n-hexane:EtOAc:MeOH ) 15:3:1) gave
4-[2-(4′-methy-biphenyl-4-yloxy)- acetylamino]-benzoic acid meth-
yl ester as a white solid (70.2 mg, 45.6% yield). Rf ) 0.45 (n-
hexane:EtOAc:MeOH ) 9:3:1). To a solution of 4-[2-(4′-methy-
biphenyl-4-yloxy)- acetylamino]-benzoic acid methyl ester (60 mg,
0.16 mmol) in THF/H2O (1:1, 10 mL) was added lithium hydroxide
monohydrate (13.4 mg, 0.32 mmol) at room temperature. The
resulting mixture was stirred overnight and then acidified with 10%
HCl to pH 7. EtOAc was added and the organic layer was separated.
After concentration, the residue was purified by crystallization from
CH2Cl2/MeOH/n-hexane to give 3-[2-(4′-methyl-biphenyl-4-yloxy)-
acetylamino]-benzoic acid as a white solid (17.5 mg, 30.3% yield).
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-N-naphtha-
len-2-yl-benzamide (12). Obtained as a colorless solid (16 mg,
61.5% yield). Rf ) 0.30 (EtOAc:n-hexane ) 3:7); mp 201.3-203.7
°C; 1H NMR (CDCl3, 300 MHz) δ 8.47 (1H, s, CONH), 8.32 (1H,
s, CONH), 8.19 (1H, s, aromatic-H), 8.12 (1H, s, aromatic-H), 7.82
(4H, m, aromatic-H), 7.68 (1H, d, J ) 8.1 Hz, aromatic-H), 7.61
(1H, dd, J ) 1.8, 9.0 Hz, aromatic-H), 7.45 (3H, m, aromatic-H),
7.33 (2H, d, J ) 8.7 Hz, aromatic-H), 6.93 (2H, d, J ) 9.3 Hz,
aromatic-H), 4.6 (2H, s, OCH2CO), 2.1 (3H, brs, adamantyl-H),
1.89 (6H, d, J ) 1.8 Hz, adamantyl-H), 1.77 (6H, m, adamantyl-
H); MS (ESI) m/z 553 (M + Na)+, 529 (M - H)-; HRMS (ESI)
m/z calcd for C35H35N2O3 [(M + H)+] 531.2641, found: 531.2611.
3-[2-(4-Adamantan-1-yl-phenoxyl)-acetylamino-N-furan-2-yl-
methyl-benzamide (13). Obtained as a yellowish solid (79 mg,
quantitative yield). Rf ) 0.45 (n-hexane:EtOAc:MeOH ) 6:3:1);
1
mp 188.8-189.7 °C; H NMR (CDCl3, 300 MHz) δ 8.42 (1H, s,
NH), 7.96 (1H, m, aromatic-H), 7.83-7.84 (1H, m, aromatic-H),
7.56 (1H, d, J ) 7.8 Hz, aromatic-H), 7.26-7.44 (4H, m, aromatic-
H), 6.92-6.95 (2H, m, aromatic-H), 6.53 (1H, m, NH), 6.30-6.35
(4H, m, aromatic-H), 4.64 (2H, dd, J ) 5.4 Hz, CH2), 4.60 (2H, s,
CH2), 2.10 (3H, m, adamantyl-H), 1.90 (6H, m, adamantyl-H), 1.77
(6H, m, adamantyl-H); MS (ESI) m/z 507 (M + Na)+, 483 (M -
H)-; HRMS (ESI) m/z calcd for C30H36O4N3 [(M + NH4)+]
502.27003, found: 502.26852.
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-N-(2-pyridin-
4-yl-ethyl)-benzamide (14). Obtained as a colorless solid (25 mg,
1
40% yield). Rf ) 0.52 (MeOH:MC ) 1:9); mp 78.3-80.4 °C; H
NMR (CDCl3, 300 MHz) δ 8.47 (3H, m, 2xCONH, aromatic-H),
7.97 (1H, s, aromatic-H), 7.75 (1H, d, J ) 8.1 Hz, aromatic-H),
7.48 (1H, d, J ) 7.2 Hz, aromatic-H), 7.33 (3H, m, aromatic-H),
7.13 (2H, d, J ) 5.4 Hz, aromatic-H), 6.90 (2H, d, J ) 9.0 Hz,
aromatic-H), 6.78 (1H, brs, aromatic-H), 4.55 (2H, s, OCH2CO),
3.68 (2H, q, J ) 6.75 Hz, NHCH2CH2), 2.91 (2H, t, J ) 6.9 Hz,
NHCH2CH2), 2.08 (3H, s, adamantyl-H), 1.87 (6H, s, adamantyl-
H), 1.75 (6H, m, adamantyl-H); MS (ESI) m/z 510 (M + H)+, 508
(M - H)-; HRMS (ESI) m/z calcd for C32H36N3O3 [(M + H)+]
510.2750, found: 510.2738.
4-[2-(3′-Nitro-biphenyl-4-yl-oxy)-acetylamino]-benzoic Acid
(15). To a mixture of 3-[2-(3′-bromo-phenoxy)-acetylamino]-
benzoic acid methyl ester 8h (100 mg, 0.27 mmol) and Pd(PPh3)4
(16.2 mg, 0.014 mmol) in 1,2-dimethoxyethane (7.0 mL) was added
3-nitrophenylboronic acid (68.4 mg, 0.41 mmol) followed by the
addition of sodium hydrogen carbonate (68.9, 0.82 mmol) in H2O
(3 mL). The reaction mixture was refluxed with vigorous stirring
for 18 h. The organic solvent was removed under reduced pressure
and then partitioned between EtOAc and brine. The organic layer
was separated, dried over anhydrous MgSO4, filtered, and concen-
trated under reduced pressure. Purification by silica gel column
chromatography (n-hexane:EtOAc:MeOH ) 15:3:1) gave 4-[2-(3′-
nitro-biphenyl-4-yl-oxy)-acetylamino]-benzoic acid methyl ester, as
a greenish solid (81 mg, 73.8% yield). Rf ) 0.38 (n-hexane:EtOAc:
MeOH ) 9:3:1); mp 162.8-165.5 °C (dec); MS (ESI) m/z 429 (M
+ Na)+, 405 (M - H)-. To a solution of 4-[2-(3′-nitro-biphenyl-
4-yl-oxy)-acetylamino]-benzoic acid methyl ester (124 mg, 0.31
mmol) in THF/H2O (1:1, 10 mL) was added lithium hydroxide
monohydrate (25.7 mg, 0.61 mmol) at room temperature. The
resulting mixture was stirred overnight and then acidified with 10%
HCl to pH 7. EtOAc was added and the organic layer was separated.
After concentration, the residue was purified by crystallization from
CH2Cl2/MeOH/n-hexane to give 4-[2-(3′-nitro-biphenyl-4-yl-oxy)-
acetylamino]-benzoic acid as a light green solid (55.9 mg, 44.9%
yield). Rf ) 0.26 (CH2Cl2:MeOH ) 15:1); mp 254.8-255.7 °C
1
Rf ) 0.22 (CH2Cl2:MeOH ) 15:1); mp 251-252.4 °C; H NMR
(DMSO-d6, 300 MHz) δ 8.25 (1H, s, aromatic-H), 7.85 (1H, m,
aromatic-H), 7.65 (1H, m, aromatic-H), 7.55 (2H, m, aromatic-H),
7.46 (2H, m, aromatic-H), 7.39 (1H, ps-t, J ) 8.1 Hz, aromatic-
H), 7.19 (2H, m, aromatic-H), 7.06 (2H, m, aromatic-H), 4.71 (2H,
s, OCH2CO), 2.30 (3H, s, CH3); MS (ESI) m/z 384 (M + Na)+,
360 (M - H)-.
3-[2-(3′-Methoxy-biphenyl-4-yl)-acetylamino]-benzoic acid (18).
3-[2-(3′-Bromo-phenoxy)-acetylamino]-benzoic acid methyl ester
8h (100 mg, 0.27 mmol) was added to a suspension of Pd(PPh3)4
(15.9 mg, 0.014 mmol) in degassed [bmim][BF4] (0.1 mL) at
ambient temperature. The mixture was heated overnight at 110 °C.
The solution was cooled to ambient temperature and sequentially
added 3-methoxylphenyl boronic acid (83.4 mg, 0.55 mmol), and
a solution of sodium hydrogen carbonate (46.2 mg, 0.55 mmol) in
H2O (0.5 mL). The mixture was reheated overnight at 110 °C with
vigorous stirring, then cooled and extracted with EtOAc. The
combined extracts were washed by brine. The organic phase was
dried over anhydrous MgSO4, and concentrated under vacuo.
Purification by silica gel column chromatography (n-hexane:EtOAc:
MeOH ) 15:3:1) gave 3-[2-(3’-methoxy-biphenyl-4-yl-xyl)-acetyl-

1682 Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7
Lee et al.
amino]-benzoic acid methyl ester as a white solid (78.1 mg, 73.9%
yield). Rf ) 0.46 (n-hexane:EtOAc:MeOH ) 9:3:1). To a solution
of 3-[2-(3′-methoxy-biphenyl-4-yl-xyl)-acetylamino]-benzoic acid
methyl ester (117 mg, 0.3 mmol) in THF/H2O (1:1, 20 mL) was
added lithium hydroxide monohydrate (25.2 mg, 0.6 mmol) at room
temperature. The resulting mixture was stirred overnight, and then
acidified with 10% HCl to pH 7. EtOAc was added and the organic
layer was separated. After concentration, the residue was purified
by recrystallization from CH2Cl2/MeOH/n-hexane) to give 3-[2-
(3′-methoxy-biphenyl-4-yl)-acetylamino]-benzoic acid as a white
solid (63.7 mg, 56.1% yield). Rf ) 0.38 (CH2Cl2:MeOH ) 15:1);
mp 184.5-187.4 °C; 1H NMR (DMSO-d6, 300 MHz) δ 10.32 (1H,
s, NH), 8.30 (1H, s, aromatic-H), 7.89 (1H, d, J ) 8.4 Hz, aromatic-
H), 7.62-7.68 (3H, m, aromatic-H), 7.46 (1H, ps-t, J ) 8.1 Hz,
aromatic-H), 7.34 (1H, ps-t, J ) 8.1 Hz, aromatic-H), 7.08-7.19
(3H, m, aromatic-H), 6.88 (1H, dd, J ) 8.1, 2.7 Hz, aromatic-H),
4.78 (2H, s, OCH2CO), 3.81 (3H, s, OCH3); MS (ESI) m/z 400 (M
+ Na)+, 376 (M - H)-; HRMS (ESI) m/z calcd for C22H23N2O5
[(M + NH4)+] 395.1601, found: 395.1598.
4-Benzyloxy-3-nitro-benzoic Acid (20). A suspension of 4-hy-
droxy-3-nitrobenzoic acid 19 (1.50 g) and K2CO3 (11.32 g) in
acetone (160 mL) was refluxed overnight under argon. After
filtration, the solution was concentrated in vacuo to give the crude
product as a yellow solid, which was taken up in methanol (350
mL) and treated with an aqueous solution of NaOH (24.57 g, in 80
mL of H2O). The mixture was stirred at room temperature for 3 h,
concentrated under reduced pressure, acidified with 10% HCl to
pH 7, and partitioned between EtOAc and water. The organic layer
was separated, washed with brine and water, dried over anhydrous
MgSO4, filtered, and concentrated in vacuo. The residue was
purified by silica gel flash column chromatography (CH2Cl2:MeOH
) 10:1) to give 4-benzyloxy-3-nitro-benzoic acid as a yellow solid
(2.05 mg, 91.5% yield). Rf ) 0.17 (CH2Cl2:MeOH ) 10:1∼6:1);
1H NMR (CDCl3, 300 MHz) δ 8.58 (1H, d, J ) 2.4 Hz, aromatic-
H), 8.23 (1H, dd, J ) 2.4, 8.7 Hz, aromatic-H), 7.36-7.48 (5H,
m, aromatic-H), 7.20 (1H, d, J ) 9.0 Hz, aromatic-H), 5.34 (2H,
s, CH2); Purity >99% (as determined by RP-HPLC, method A, tR
) 13.3 min).
for 1 h at room temperature. Then, 3-amino-4-hydroxybenzoic acid
methyl ester (125.4 mg, 0.75 mmol) and pyridine (0.05 mL) were
added, and the reaction was stirred overnight at room temperature.
The reaction mixture was diluted with EtOAc and 10% HCl. The
organic layer was sequentially washed with brine and water, dried
over anhydrous MgSO4, filtered, and concentrated under reduced
pressure. The resulting crude solid was purified by flash column
chromatography (n-hexane:EtoAc:MeOH ) 6:3:1) to give 23 as a
white solid (183.2 mg, 84.10% yield). Rf ) 0.68 (n-hexane:EtOAc:
1
MeOH ) 6:3:1). H NMR (DMSO-d6, 300 MHz) δ 11.10 (1H, s,
OH), 9.24 (1H, s, NH), 8.69 (1H, m, aromatic-H), 7.60-7.64 (1H,
m, aromatic-H), 7.30 (2H, d, J ) 8.4 Hz, aromatic-H), 6.94-6.99
(3H, m, aromatic-H), 4.74 (2H, s, CH2), 3.79 (3H, s, CH3), 2.04
(3H, m, adamantyl-H), 1.83 (6H, m, adamantyl-H), 1.72 (6H, m,
adamantyl-H); MS (ESI) m/z 434 (M - H)-; HRMS (ESI) m/z
calcd for C26H29O5NNa [(M + Na)+] 458.1943, found: 458.1942.
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-
benzoic Acid (25): EDCI (500.4 mg, 2.61 mmol) and HOBt (352.6
mg, 2.61 mmol) were added to a mixture of (4-adamantan-1-yl-
phenoxy)acetic acid (5a, 496.5 mg, 1.74 mmol), 3-amino-4-
hydroxy-benzoic acid 2-trimethylsilyl-ethyl ester (22, 527.0 mg,
2.08 mmol), and DIPEA (337.3 mg, 0.45 mL, 2.61mmol) in DMF
(17.5 mL). The resulting reaction mixture was stirred overnight at
50 °C and then partitioned between EtOAc and 10% HCl. The
organic phase was washed with brine, dried over anhydrous MgSO4,
filtered, and concentrated under reduced pressure. The residue was
purified by silica gel flash column chromatography (n-hexane:
EtOAc ) 3:1) to give 3-[2-(4-adamantan-1-yl-phenoxy)acetyl-
amino]-4-hydroxybenzoic acid 2-trimethylsilyl-ethyl ester 24 as a
white solid (521.5 mg, 51.0% yield). Rf ) 0.5 (n-hexane:EtOAc )
1
5:1); H NMR (DMSO-d6, 300 MHz) δ 9.24 (1H, s, NH), 8.67
(1H, m, aromatic-H), 7.57-7.61 (1H, m, aromatic-H), 7.30 (2H,
d, J ) 9.3 Hz, aromatic-H), 6.92-6.96 (3H, m, aromatic-H), 4.73
(2H, s, CH2), 4.32 (2H, t, J ) 8.1 Hz, CH2), 2.04 (3H, m,
adamantyl-H), 1.83 (6H, m, adamantyl-H), 1.72 (6H, m, adamantyl-
H), 1.08-1.13 (2H, t, J ) 7.81 Hz, CH2); MS (ESI) m/z 544 (M
+ Na)+, 520 (M - H)-. To an ice-cooled solution of 24 (516.5
mg, 0.99 mmol) in dry THF (30 mL) was added n-Bu4NF (14.86
mL, 1 M in THF), the mixture was stirred overnight at room
temperature, and then the mixture was partitioned between EtOAc
and 10% HCl. The organic layer was sequentially washed with brine
and water, dried over anhydrous MgSO4, filtered, and concentrated
under reduced pressure. The resulting residue was purified by silica
gel flash column chromatography (CH2Cl2:MeOH ) 10:1) to give
25 as a white solid (330.2 mg, 79.1% yield). Rf ) 0.4 (n-hexane:
3-Amino-4-hydroxy-benzoic acid 2-trimethylsilanyl-ethyl Es-
ter (22). To a mixture of 4-benzyloxy-3-nitro-benzoic acid 20 (1.87
g, 6.86 mmol) and HBTU (3.31 g, 10.30 mmol) in DMF (25 mL)
was added 2-(trimethylsilyl)ethanol (1.22 g, 10.30 mmol) and
DIPEA (1.29 g, 1.73 mL, 10.30 mmol). The reaction mixture was
stirred overnight at room temperature, and then partitioned between
ethyl acetate and 10% HCl. The organic layer was separated,
washed with brine, dried over anhydrous MgSO4, and concentrated
under reduced pressure. The residue was purified by silica gel flash
column chromatography (n-hexane:EtOAc ) 10:1) to give 4-ben-
zyloxy-3-nitro-benzoic acid 2-trimethylsilylethyl ester as a yellow
solid (1.97 g, 96.9% yield). Rf ) 0.3 (n-hexane:EtOAc:MeOH )15:
1
EtOAc ) 10:1); H NMR (DMSO-d6, 300 MHz) δ 9.26 (1H, s,
NH), 8.64 (1H, s, aromatic-H), 7.56 (1H, d, J ) 8.7 Hz, aromatic-
H), 7.29 (2H, d, J ) 8.4 Hz, aromatic-H), 6.90-6.96 (3H, m,
aromatic-H), 4.71 (2H, s, CH2), 2.03 (3H, m, adamantyl-H), 1.72-
1.82 (12H, m, adamantyl-H); MS (ESI) m/ z 420 (M - H)-; HRMS
(ESI) m/z calcd for C25H27O5NNa [(M + Na)+] 444.1784, found:
444.1787.
1
3:1); H NMR (CDCl3, 300 MHz) δ 8.51 (1H, d, J ) 2.7 Hz,
aromatic-H), 8.17 (1H, dd, J ) 1.8, 9.0 Hz, aromatic-H), 7.34-
7.47 (5H, m, aromatic-H), 7.16 (1H, d, J ) 8.4 Hz, aromatic-H),
4.39-4.45 (2H, m, CH2), 1.10-1.16 (2H, m, CH2), 0.08 (9H, s,
CH3). 4-Benzyloxy-3-nitro-benzoic acid 2-trimethylsilyl-ethyl ester
(1.97 g, 5.27 mmol) was taken up in methanol and treated with
5% Pd-carbon (5% w/w), and stirred at room temperature under
1 psi hydrogen gas pressure. After completion of the reaction as
monitored by TLC, the mixture was filtered through a Celite bed
and concentrated under reduced pressure. The residue was purified
by silica gel flash column chromatography (CH2Cl2:EtOAc ) 10:
1) to give 3-amino-4-hydroxy-benzoic acid 2-trimethylsilyl-ethyl
ester as a yellow solid (988.7 mg, 74.1% yield). Rf ) 0.2 (n-hexane:
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-
benzamide (26). A solution of NH4Cl (6.5 mg, 0.12 mmol) in dry
toluene (2 mL) was treated with trimethylaluminium (2.0 M in
hexane) (0.26 mL. 0.51 mmol) and stirred for 0.25 h at room
temperature. To the mixture was added a solution of 3-[2-(4-
adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-benzoic acid meth-
yl ester (50.1 mg, 0.12 mmol) in toluene (4 mL), and it was stirred
at 80 °C for 3 h. Then the reaction mixture was allowed to cool
and was treated with dilute HCl, until no more effervescense was
observed. The reaction mixture was then partitioned between EtOAc
and saturated NaHCO3 solution. The organic phase was washed
with brine, dried over anhydrous MgSO4, filtered, and concentrated
under reduced pressure. The residue was purified by preparative
TLC (CH2Cl2:MeOH ) 15:1) to give 3-[2-(4-adamantan-1-yl-
phenoxy)-acetylamino]-4-hydroxy-benzamide as a white solid (12.9
mg, 25.6% yield). Rf ) 0.16 (n-hexane:EtOAc:MeOH ) 6:3:1);
1H NMR (CDCl3 + CD3OD, 300 MHz) δ 8.26 (1H, d, J ) 2.4 Hz,
aromatic-H), 7.23 (1H, d, J ) 2.1 Hz, aromatic-H), 6.99 (2H, d, J
) 9.3 Hz, aromatic-H), 6.64 (2H, d, J ) 9.3 Hz, aromatic-H), 6.59
1
EtOAc:MeOH )15:3:1); H NMR (CDCl3, 300 MHz) δ 7.39-
7.44 (2H, m, aromatic-H), 6.78 (1H, d, J ) 8.1 Hz, aromatic-H),
4.34-4.39 (2H, m, CH2), 1.08-1.13 (2H, m, CH2), 0.08 (9H, s,
CH3); MS (ESI) m/z 252 (M - H)-.
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-
benzoic Acid methyl Ester (23). Oxalyl chloride (178.5 mg, 0.11
mL, 1.5 mmol) was added to a solution of 5a (143.2 mg, 0.5mmol)
and one drop of DMF in THF (5 mL), and the mixture was stirred

(Aryloxyacetylamino)benzoic Acid Analogues
Journal of Medicinal Chemistry, 2007, Vol. 50, No. 7 1683
(1H, d, J ) 8.7 Hz, aromatic-H), 4.25 (2H, s, CH2), 1.75 (3H, m,
adamantyl-H), 1.56 (6H, m, adamantyl-H), 1.44 (6H, m, adamantyl-
H); MS (ESI) m/z 443 (M + Na)+, 419 (M - H)-; HRMS (ESI)
m/z calcd for C25H28O4N2Na [(M + Na)+] 443.1947, found:
443.1944.
(2H, s, CH2), 3.63 (2H, t, J ) 6.6 Hz, CH2), 2.93 (2H, t, J ) 6.6
Hz, CH2), 2.60 (6H, s, CH3), 2.08 (3H, m, adamantyl-H), 1.91 (6H,
m, adamantyl-H), 1.81 (6H, m, adamantyl-H); MS (ESI) m/z 492
(M + H)+, 490 (M - H)-; HRMS (ESI) m/z calcd for C29H37O4N3-
Na [(M + Na)+] 514.2682, found: 514.2689.
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-
N,N-dimethyl-benzamide (27). A solution of dimethylamine (0.06
mL, 0.12 mmol) in dry toluene (2 mL) was treated with trimethyl-
aluminium (2.0 M in hexane) (0.15 mL. 0.31 mmol) and stirred
for 0.25 h at room temperature. To the mixture was added a solution
of the 3-[2-(4-adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-
benzoic acid methyl ester (30.1 mg, 0.07 mmol) in toluene (8 mL),
and it was stirred at 80 °C for 3 h. The reaction mixture was allowed
to cool and was treated with dilute HCl, until no more effervescense
was observed. The reaction mixture was then partitioned between
EtOAc and water. The organic phase was washed with brine, dried
over anhydrous MgSO4, filtered, and concentrated under reduced
pressure. The residue was purified by preparative TLC (n-hexane:
EtOAc:MeOH ) 15:3:1) to give 3-[2-(4-adamantan-1-yl-phenoxy)-
acetylamino]-4-hydroxy-N,N-dimethyl-benzamide as a white solid
(10.4 mg, 23.2% yield). Rf ) 0.25 (n-hexane:EtOAc:MeOH ) 6:3:
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-N-
(3-morpholin-4-yl-propyl)-benzamide (30). 3-Morpholin-4-yl-
propylamine (0.03 mL, 0.18 mmol) and DIPEA (0.03 mL, 0.18
mmol) were added to a solution of 3-[2-(4-adamantan-1-yl-
phenoxy)-acetylamino]-4-hydroxy-benzoic acid 25 (50 mg, 0.12
mmol) and HATU (68.5 mg, 0.18 mmol) in DMF (3 mL), and the
resulting reaction mixture was stirred overnight at room temperature.
The mixture was partitioned between EtOAc and brine. The organic
layer was separated, dried over anhydrous MgSO4, filtered, and
concentrated under reduced pressure. Purification by preparative
TLC (CH2Cl2:MeOH ) 15:1) gave 3-[2-(4-adamantan-1-yl-phe-
noxy)-acetylamino]-4-hydroxy-N-(3-morpholin-4-yl-propyl)-benz-
amide, as a colorless solid (9.5 mg, 14.5% yield). Rf ) 0.35 (CH2-
1
Cl2:MeOH ) 10:1); H NMR (CD3OD, 300 MHz) δ 8.57 (1H, d,
J ) 2.4 Hz, aromatic-H), 7.51 (1H, dd, J ) 2.4, 8.7 Hz, aromatic-
H), 7.33 (2H, d, J ) 8.7 Hz, aromatic-H), 6.98 (2H, d, J ) 8.7 Hz,
aromatic-H), 6.92 (1H, d, J ) 8.7 Hz, aromatic-H), 4.67 (2H, s,
CH2), 3.76-3.81 (4H, m, aliphatic-H), 6.92 (2H, t, J ) 6.9 Hz,
aliphatic-H), 2.71-2.79 (6H, m, aliphatic-H), 2.07 (3H, m, ada-
mantyl-H), 1.91 (8H, m, adamantyl-H and aliphatic-H), 1.80 (6H,
m, adamantyl-H); MS(ESI) m/z 548 (M + H)+, 546 (M - H)-;
HRMS (ESI) m/z calcd for C32H42O5N3 [(M + H)+] 548.3124,
found: 548.3121.
1
1); H NMR (CDCl3, 300 MHz) δ 8.85 (1H, s, NH), 7.70 (1H, s,
aromatic-H), 7.32 (2H, d, J ) 8.4 Hz, aromatic-H), 7.03-7.05 (1H,
m, aromatic-H), 6.93 (2H, d, J ) 8.7 Hz, aromatic-H), 6.85 (1H,
d, J ) 7.2 Hz, aromatic-H), 4.61 (2H, s, CH2), 3.07 (6H, s, CH3),
2.09 (3H, m, adamantyl-H), 1.89 (6H, m, adamantyl-H), 1.76 (6H,
m, adamantyl-H); MS (ESI) m/z 471 (M + Na)+, 447 (M - H)-;
HRMS (ESI) m/z calcd for C27H32O4N2Na [(M + Na)+] 471.2260,
found: 471.2261.
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-N-furan-2-yl-
methyl-4-hydroxy-benzamide (28). A solution of furfurylamine
(6.8 mg, 0.07 mmol, 0.07 mL) in dry toluene (1 mL) was treated
with trimethylaluminium (2.0 M in hexane) (0.15 mL. 0.31 mmol)
and stirred for 0.25 h at room temperature. To the mixture was
added a solution of the 3-[2-(4-adamantan-1-yl-phenoxy)-acetyl-
amino]-4-hydroxy-benzoic acid methyl ester (30.1 mg, 0.07 mmol)
in toluene (8 mL), and it was stirred at 80 °C for 3 h. The reaction
mixture was allowed to cool and was treated with dilute HCl, until
no more effervescense was observed. The reaction mixture was
then partitioned between EtOAc and water. The organic phase was
washed with brine, dried over anhydrous MgSO4, filtered, and
concentrated under reduced pressure. The residue was purified by
preparative TLC (CH2Cl2:MeOH ) 15:1) to give 3-[2-(4-adaman-
tan-1-yl-phenoxy)-acetylamino]-N-furan-2-ylmethyl-4-hydroxy-
be nzamide as a white solid (15.4 mg, 44.0% yield). Rf ) 0.34
(n-hexane:EtOAc:MeOH ) 6:3:1); 1H NMR (CDCl3, 300 MHz) δ
8.71 (1H, s, NH), 7.76 (1H, s, aromatic-H), 7.48 (1H, d, J ) 9.0
Hz, aromatic-H), 7.33-7.38 (3H, m, aromatic-H), 7.04 (1H, d, J
) 8.1 Hz, aromatic-H), 6.95 (2H, d, J ) 9.0 Hz, aromatic-H), 6.44
(1H, s, NH), 6.32 (2H, d, J ) 8.7 Hz, aromatic-H), 4.62-4.69 (4H,
m, CH2), 2.10 (3H, m, adamantyl-H), 1.90 (6H, m, adamantyl-H),
1.77 (6H, m, adamantyl-H); MS (ESI) m/z 523 (M + Na)+, 499
(M - H)-; HRMS (ESI) m/z calcd for C30H32O5N2Na [(M + Na)+]
523.2209, found: 523.2214.
3-[2-(4-Adamantan-1-yl-phenoxy)-acetylamino]-N-(2-dimeth-
ylamino-ethyl) -4-hydroxy-benzamide (29). A solution of 3-[2-
(4-adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-benzoic acid
25 (70.1 mg, 0.17 mmol), N,N-dimethyl-ethylenediamine (22.1 mg,
0.25 mmol, 0.03 mL), EDCI (48.0 mg, 0.25 mmol), HOBT (34.0
mg, 0.25 mmol), and DIPEA (0.05 mL, 0.25 mmol) in DMF (5
mL) was stirred overnight at 60 °C. The mixture was cooled to
room temperature and partitioned between EtOAc and water. The
organic phase was washed with brine, dried over anhydrous MgSO4,
filtered, and concentrated under reduced pressure. The residue was
purified by preparative TLC (CH2Cl2:MeOH ) 20:1) to give 3-[2-
(4-adamantan-1-yl-phenoxy)-acetylamino]-N-(2-dimethylamino-
ethyl)-4-hydr oxy-benzamide as a colorless solid (9.7 mg, 11.6%
yield). Rf ) 0.16 (CH2Cl2:MeOH ) 10:1); 1H NMR (CD3OD, 300
MHz) δ 8.26 (1H, m, aromatic-H), 7.85 (1H, dd, J ) 1.8 and 9.0
Hz, aromatic-H), 7.45-7.47 (1H, m, aromatic-H), 7.36 (2H, d, J
) 9 Hz, aromatic-H), 7.02 (2H, d, J ) 6.6 Hz, aromatic-H), 4.73
Acknowledgment. This study was supported by a grant from
KRIBB Research Initiative Program, Korea, and the Molecular
and Cellular BioDiscovery Research Program (M10601000155),
Korea.
Supporting Information Available: A table listing HPLC
retention times and purities for 1, 8a, 9d-i, 10a-j, 11-18, 23,
and 25-30, and biological procedures. This material is available
free of charge via the Internet at http://pubs.acs.org.
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