Synthesis and evaluation of novologues as C-terminal Hsp90 inhibitors with cytoprotective activity against sensory neuron glucotoxicity

Article abstract of DOI:10.1021/jm300544c

Compound 2 (KU-32) is a first-generation novologue (a novobiocin-based, C-terminal, heat shock protein 90 (Hsp90) inhibitor) that decreases glucose-induced death of primary sensory neurons and reverses numerous clinical indices of diabetic peripheral neuropathy in mice. The current study sought to exploit the C-terminal binding site of Hsp90 to determine whether the optimization of hydrogen bonding and hydrophobic interactions of second-generation novologues could enhance neuroprotective activity. Using a series of substituted phenylboronic acids to replace the coumarin lactone of 2, we identified that electronegative atoms placed at the meta-position of the B-ring exhibit improved cytoprotective activity, which is believed to result from favorable interactions with Lys539 in the Hsp90 C-terminal binding pocket. Consistent with these results, a meta-3-fluorophenyl substituted novologue (13b) exhibited a 14-fold lower ED₅₀ for protection against glucose-induced toxicity of primary sensory neurons compared to 2.

Full text of DOI:10.1021/jm300544c

Article
pubs.acs.org/jmc
Synthesis and Evaluation of Novologues as C-Terminal Hsp90
Inhibitors with Cytoprotective Activity against Sensory Neuron
Glucotoxicity
Bhaskar Reddy Kusuma,† Liang Zhang,‡ Teather Sundstrom,† Laura B. Peterson,† Rick T. Dobrowsky,‡
and Brian S. J. Blagg†,*
†Department of Medicinal Chemistry, The University of Kansas, 1251 Wescoe Hall Drive, Malott Hall 4070, Lawrence, Kansas
66045-7563, United States
‡Pharmacology and Toxicology Department, The University of Kansas, Lawrence, Kansas 66045, United States
S
* Supporting Information
ABSTRACT: Compound 2 (KU-32) is a first-generation
novologue (a novobiocin-based, C-terminal, heat shock
protein 90 (Hsp90) inhibitor) that decreases glucose-induced
death of primary sensory neurons and reverses numerous
clinical indices of diabetic peripheral neuropathy in mice. The
current study sought to exploit the C-terminal binding site of
Hsp90 to determine whether the optimization of hydrogen
bonding and hydrophobic interactions of second-generation
novologues could enhance neuroprotective activity. Using a
series of substituted phenylboronic acids to replace the
coumarin lactone of 2, we identified that electronegative
atoms placed at the meta-position of the B-ring exhibit improved cytoprotective activity, which is believed to result from favorable
interactions with Lys539 in the Hsp90 C-terminal binding pocket. Consistent with these results, a meta-3-fluorophenyl
substituted novologue (13b) exhibited a 14-fold lower ED50 for protection against glucose-induced toxicity of primary sensory
neurons compared to 2.
Hsp70. Importantly, small molecule inhibition of Hsp90 is
sufficient to induce the HSR. Compound 2 (KU-32)5,6 is a
small molecule Hsp90 C-terminal inhibitor that is based on
novobiocin 1, a naturally occurring antimicrobial agent that
inhibits DNA gyrase (Figure1). Although the etiology of DPN
INTRODUCTION
■
Approximately 26 million Americans are afflicted with either
type 1 or type 2 diabetes. Despite the use of insulin and oral
antidiabetic medications to help maintain euglycemia, about
60−70% of these individuals develop diabetic peripheral
neuropathy (DPN).1 To date, approaches toward the treatment
of DPN have centered on pathways/targets directly linked to
hyperglycemia (i.e., polyol and hexosamine pathways, advanced
glycation end products (AGEs), enhanced oxidative stress, and
PKC activation).2 Unfortunately, the contribution of these
targets/pathways to the progression of DPN differs between
individuals and does not occur with biochemical uniformity,
and consequently, these approaches have resulted in little
success for the management of DPN. As an alternative
approach, we have explored the pharmacologic modulation of
molecular chaperones to promote a broad cytoprotective
response that may enhance a patient’s ability to tolerate
hyperglycemic insults and improve the symptoms of DPN.
Molecular chaperones, such as heat shock proteins 90 and 70
(Hsp90, Hsp70), are essential for folding nascent polypeptides
into their biologically active structures and for the refolding of
aggregated and denatured proteins that occur upon cellular
stress.3,4 Numerous conditions that cause cell stress can also
induce the “heat shock response” (HSR): the transcriptional
upregulation of antioxidant genes and chaperones such as
Figure 1. Chemical structures of novobiocin 1 and 2 (KU-32).
is unrelated to the accumulation of one specific misfolded or
aggregated protein, hyperglycemia can increase oxidative stress
and the oxidative modification of amino acids7 that impair
Received: February 16, 2012
Published: June 15, 2012
© 2012 American Chemical Society
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Figure 2. (A) Compound 2 docked to Hsp90 C-terminal binding site. (B) Novologue docked to Hsp90 C-terminal binding site. (C) Overlay of 2
and novologue docked to Hsp90 C-terminal binding site. All structures docked into Hsp90α open homology model. (D) Structure of novologue and
its attributes.
protein folding,8 decrease mitochondrial protein import,9 and
promote mitochondrial dysfunction.2,7a Even in the absence of
a single, disease-specific protein aggregate, we have shown that
pharmacologic induction of cytoprotective molecular chaper-
ones can improve myelinated and unmyelinated fiber function
in cellular models of glucotoxic stress and animal models of
DPN.10 Mechanistically, compound 2 was ineffective at
preventing neuregulin-induced demyelination of myelinated
cultures of sensory neurons prepared from Hsp70.1 and 70.3
double knockout mice, indicating that Hsp70 is necessary for
the neuroprotective activity manifested by compound 2.
Similarly, weekly treatment with 2 restored normal sensory
and motor nerve function in diabetic wild type mice but was
unable to reverse multiple clinical indices of DPN in the
diabetic Hsp70 knockout mice.10 Collectively, these studies
provide the biological and clinical rationale to support the
modulation of molecular chaperones as a viable approach
toward treating.
An enviable aspect of 2 is that it induces Hsp70 at
concentrations well below those needed to inhibit Hsp90's
protein folding ability, thus, it possesses a rather broad
therapeutic window that dissociates cytoprotective properties
from potentially cytotoxic effects resulting from the degradation
of Hsp90-dependent client proteins.4 We have previously
shown that molecules containing a benzamide, as found in
novobiocin, exhibit antiproliferative activities, whereas mole-
cules such as 2, containing an acetamide, manifest neuro-
protective properties. However, these prior studies sought to
evaluate structure−activity relationships for novobiocin ana-
logues as anticancer agents11,12 rather than exploring chemical
attributes that enhance the neuroprotective properties of
novobiocin-based analogues. Therefore, the goal of this work
was to determine whether diversification of the scaffold of
compound 2 could identify structure−activity relationships
(SAR) for novobiocin analogues (novologues) that enhance the
neuroprotective properties manifested by Hsp90 C-terminal
inhibitors.
Recently, we used molecular modeling and azide-containing
novobiocin derivatives as photoaffinity probes to elucidate, for
the first time, the Hsp90 C-terminal binding site.13 As shown in
Figure 2A−C, compound 2 docks to this region and appears to
exhibit binding interactions with both the protein backbone and
the amino acid side chains similar to those manifested by
novobiocin. Interestingly, the coumarin lactone of 2 appears
too distant from Lys539 to provide complementary interactions
with this residue. In addition, the 3-amido side chain appears to
project into a large hydrophobic pocket that could accom-
modate more flexible linkers. As a consequence of these
observations, the novologue scaffold (Figure 2D) was designed
to project the B-ring into the pocket wherein Lys539 resides
and to serve as a lead compound for further diversification. In
addition, the flexible ethyl amide projecting from the A-ring
could accommodate a number of orientations that could better
occupy the large hydrophobic pocket that remains vacant in the
presence of 2.
On the basis of the novologue design, we envisioned
construction of a parallel library to validate this scaffold for use
as a neuroprotective agent. The library was designed so that the
3′-carbamate on noviose was omitted, on the basis of prior
studies that showed this group to be detrimental to Hsp90
inhibitory activity.5 In contrast, additional hydrophobic and
hydrogen bonding interactions could be provided by the
incorporation of functionalities onto the 3-aryl substituent (B-
ring), which was designed to provide complementary
interactions with Lys539. The 4-ethyl acetamide was included
to occupy the binding pocket about the coumarin ring system.
Consistent with data obtained from prior studies, the 7-noviosyl
linkage was maintained as well as the requisite 2′,3′-diol. In this
article, we report the parallel synthesis of rationally designed
novologues as Hsp90 C-terminal inhibitors and assessment of
their neuroprotective activities.
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ether 6,14 and the 2-phenol converted to triflate 7 using
trifluoromethanesulfonic anhydride and triethylamine (Scheme
2). Compound 7 was subsequently coupled with commercially
available aryl boronic acids (4a−p) under standard Suzuki
conditions15,16 to give biaryl ring systems 8a−p in good yields.
Benzaldehydes 8a−p were converted to the corresponding
nitrostyrenes (9a−p), following a Henry reaction with
nitromethane and ammonium acetate.17,18 Reduction of the
nitro and olefin functionalities with lithium aluminum hydride
was followed by acylation of the resulting amines to afford
acetamides 10a−p in good yields. The benzyl ether of
compounds 10a−p was cleaved under hydrogenolysis con-
ditions to afford phenols 11a−p, which were coupled with the
tricloroacetimidate of noviose carbonate 125,19 in the presence
of a catalytic amount of boron trifluoride etherate. The
resulting noviosylated biaryl systems were exposed to
methanolic ammonia to solvolyze the cyclic carbonate and
give the desired novologues (13a−p) in good to moderate
yields.
RESULTS AND DISCUSSION
Retrosynthetically, a library of novologues was envisioned for
construction via four components (Scheme 1): a resorcinolic
■
Scheme 1. Retrosynthetic Analysis for the Construction of
Novologues
In addition, two cyclohexene analogues 22a−b were pursued
to test our hypothesis regarding the region surrounding the
flexible side chain (Scheme 3). Although these molecules
contain the same linker length, these analogues contain a bulky
cyclohexane tether between the biaryl ring system and the
acetamide.
benzaldehyde (3), a variety of commercially available boronic
acids (4a−p), noviose (5), and the acetamide side chain
(Scheme 1). Prior work from our laboratory demonstrated that
the trichloroacetimidate of noviose carbonate undergoes rapid
coupling with phenols to give the desired α-anomer in high
yield.
The boronic acids chosen for this study contain both
electronic and steric moieties that could aid in elucidation of
structure−activity relationships and provide crucial interactions
with Lys539 and the surrounding pocket. Toward this goal,
phenylboronic acids (Figure 3) containing electronegative
Synthesis of cyclohexene analogues 22a−b began with the
previously described phenol 6, which was protected as the
methoxymethyl (MOM) ether 1420 before the aldehyde of
which was converted to nitrostyrene 15 under Henry
conditions.16 The electron deficient nitrostyrene (15) was
subjected to a Diels−Alder cycloaddition with excess butadiene
to give an enantiomeric mixture of cyclohexene derivative 16 in
excellent yield.21 The nitro group of 16 was selectively reduced
to the amine via zinc dust and acidic isopropyl alcohol,22
followed by acetylation to afford acetamide 17 in 71% yield
over two steps. To construct the biaryl ring system, the MOM-
ether was cleaved to give the phenol, which was then converted
to the corresponding triflate, 19. A Suzuki reaction between 19
and 3-fluorophenylboronic acid (4b) or 3-(trifluoromethyl)
phenylboronic acid (4f) yielded biaryl compounds 20a or 20b,
respectively. Finally, boron trifluoride etherate promoted
removal of the benzyl ether23 on compounds 20a−b and
gave phenols 21a−b. Lewis acid-catalyzed noviosylation of
21a−b, with activated noviose carbonate (10), followed by
methanolysis, afforded an inseparable mixture of diastereomeric
products, 22a−b.
Evaluation of Neuroprotective Efficacy. Upon synthesis
of ethyl acetamide side chain novologues 13a−p that contain
various substitutions on the B-ring (hydrogen bond acceptors,
hydrogen bond donors, hydrophobic groups, and a tertiary
amine), their neuroprotective efficacy against glucose-induced
toxicity of embryonic dorsal root ganglion (DRG) sensory
neuron cultures was evaluated. As shown in Table 1, meta-
substituted acetamide novologues (13b, 13e, and 13f) showed
significant protection against glucotoxicity and were compara-
ble to that observed with compound 2. Although the
corresponding ortho- and para- substituted (13c, 13d, and
13g) derivatives showed significant protection against glucose-
induced cell death, they were modestly less effective than
novologues 13b, 13e, and 13f. However, in the case of
analogues 13i (ortho-OMe) and 13j (meta-OMe), the opposite
trend was observed. Electronegative atoms at the meta-position
(F, Cl, CF3) exhibited greater cytoprotective activity, which is
Figure 3. Boronic acids selected for incorporation into novologue X
scaffold.
atoms at the meta- and para-positions were explored. In
addition, hydrogen bond acceptors were included at these
locations to provide potential hydrogen bonding interactions
with the protonated form of Lys539. To serve as controls,
hydrophobic groups (4j, 4k) and a tertiary amine (4l) were
included in this series.
The synthesis of ethyl acetamide side chain containing
novologues 13a−p began with commercially available 2,4-
dihydroxybenzaldehyde, 3. The 4-phenol of resorcinolic
benzaldehyde 3 was protected as the corresponding benzyl
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a
Scheme 2. Synthesis of Ethyl Acetamide Side Chain Containing Novologues
a
Reagents and conditions: (a) NaHCO3, BnBr, CH3CN, rt, 75%; (b) Tf2O, Et3N, CH2Cl2, 60%; (c) 4a−p, Pd(PPh3)4, K2CO3, DMF, 65−92%; (d)
TBSCl, imid, CH2Cl2; (e) CH3NO2, NH4OAc, 90−98%; (f) LiAlH4, THF, 0 °C-rt, 30 min; (g) Ac2O, Et3N, 61−72% over 2 steps; (h) H2, Pd/C,
MeOH, 69−81%; (i) 12, BF3.OEt2, CH2Cl2, rt; (j) Et3N, MeOH, rt, overnight, 55−88% over 2 steps; (k) TBAF, THF, rt, 30 min.
a
Scheme 3. Synthesis of Cyclohexene Containing Novologues
a
Reagents and conditions: (a) MOMCl, DIPEA, CH2Cl2, rt, 84%; (b) CH3NO2, NH4OAc, 84%; (c) 1,4-butadiene, toluene 120 °C, 95%; (d) Zn
dust, 1N HCl; (e) Ac2O, Et3N, 71% over 2 steps; (f) HCl, MeOH; (g) phenyl triflimide, Et3N, 85%; (h) 4b or 4f, Pd(PPh3)4, K2CO3, DMF; (i)
HSEtSH, BF3·OEt2,CH2Cl2; (j) 12, BF3·OEt2, CH2Cl2; (k) Et3N, MeOH, rt, overnight.
believed to result from favorable interactions with Lys539 in the
Hsp90 C-terminal binding pocket. Consistent with this
hypothesis, increasing the size of the electronegative atom at
the meta-position (F to Cl to CF3) resulted in a decrease in
neuroprotective activity. Analogue 13b (meta-F) was among
the most cytoprotective (95% 14) compounds evaluated.
Electronegative atoms at the ortho- or para-position on ring
B (13c, 13d, and 13g) manifested activities comparable to the
unsubstituted analogue (13a) and were less active than the
corresponding meta-substituted analogues (13b, 13e, and 13f).
Although novologues 13d and 13g manifested protection
against neuronal glucotoxicity, they were less effective than our
previous compound 2 and 13b. Hydrogen bond donors at the
para-position (13m) appeared to be undesired as 13m (para-
OH) was unable to provide significant protection against
glucotoxicity. It was also somewhat, but not significantly less
protective than the unsubstituted analogue (13a).
On the other hand, hydrogen bond acceptors at the para-
position (13c and 13g) protected against glucose-induced
neuronal death but did not display significantly increased
protection compared to the novologue containing a para-
position hydrogen bond donor (13m).
Pyridine-containing analogues (13o−p) were also synthe-
sized and evaluated for neuroprotective activity. The 3-pyridine
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Neuroprotective activity was also determined for the
cyclohexene-containing novologues (22a−b) that contain the
fluoro or trifluoromethane substituent at the meta-position of
ring B. In general, cyclohexene-containing analogues 22a−b
were less efficacious than the corresponding derivatives that
contain a flexible side chain (13b versus 22a, and 13f versus
22b). Although not statistically different, novologue 22a (meta-
F) exhibited slightly better cytoprotective activity than analogue
22b (meta-CF3), which follows the same trend observed for
flexible acetamide-containing compounds (13b versus 13f).
Although these data are inconsistent with our hypothesis that
accommodation of the hydrophobic pocket would improve
efficacy, the cyclohexene ring may exceed the space allowed in
this binding cleft.
The data in Table 1 clearly support that the majority of
novologues synthesized decrease neuronal toxicity induced by
hyperglycemic stress. Although some of these compounds
appear more effective than compound 2 at 1 μM, the
differences were relatively minor. Therefore, to further
scrutinize their efficacy, compounds exhibiting high neuro-
protective activity were further evaluated for determination of
EC50 values. Because the difference in efficacy for novologues
with meta-F and meta-CF3 substitutions on 13b and 13f were
not significantly different from 2 or each other at 1 μM, the
EC50 values for these compounds were determined alongside
13h, 13l, 13n, and 13o. As shown in parts A and B of Figure 4,
EC50 values were significantly improved upon closer inspection
and clear distinctions were obtained. Novologue 13b yielded an
Table 1. Cell Viability Data of Ethyl Acetamide Side Chain
Containing Novologues
a
entry
R1
R2
R3
X
Y
% of cell viability
86
76 11#
2
2
b
13a
13b
13c
13d
13e
13f
13g
13h
13i
13j
13k
13l
H
H
H
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
b
H
F
H
F
95 14#
75 27#
b
H
H
bc
,
Cl
H
H
H
H
H
CF3
H
H
H
H
H
71 21#,*
b
Cl
CF3
H
90 23#
b
H
83 16#
bc
,
H
74 19#,*
b
SMe
OMe
H
H
83 40#
b
H
92 10#
b
OMe
Me
78 34#
b
H
82 30#
b
H
CH2-N-
morpholine
83 26#
c
13m
13n
13o
13p
H
H
H
H
H
OH
C
C
N
C
C
C
C
N
67 10*
b
−OCH2O−
83 18#
c
H
H
H
61 7*
b
H
81 12#
a
In the presence of 1 μM of each novologue +20 mM excess glucose.
Viability in the presence of 20 mM excess glucose + DMSO was 54%
EC50 value (13.0
3.6 nM) that was approximately 14-fold
lower than compound 2 (240.2 42.5 nM) or 13f (187.7
43.5 nM). Similar results were also observed for novologue
b
c
2. #, p < 0.05 versus glucose + DMSO. *, p < 0.05 versus glucose
+ compound 2 (n = 6−24) per novologue.
13n, which exhibited an EC50 value of 18.4
3.2 nM. In
contrast, novologue 13h which manifested similar efficacy to
compound 2 at 1 μM, exhibited an EC50 of 384 108 nM,
approximately 1.6-fold greater than 2.
The data in Figure 4 demonstrate that novologues 13b, 13i,
and 13n are more cytoprotective than the initial lead
compound 2. Since we have previously shown that the
cytoprotective activity manifested by compound 2 requires
Hsp70,10 we determined the ability of the novologues to induce
Hsp70 relative to 2. To this end, a luciferase reporter assay was
analogue (13o) was unable to protect against glucose-induced
toxicity and was also significantly less protective than the
corresponding 4-pyridine analogue, 13p, 2, and the unsub-
stituted phenyl analogue, 13a. Although the 4-pyridine-
containing analogue (13p) demonstrated a modestly improved
neuroprotective activity when compared to the simple phenyl
analogue 13a, this difference in efficacy was not significant.
Figure 4. Determination of EC50 of select novologues. (Left Panel) DRG sensory neurons were incubated in the absence or presence of 0.1−1000
nM of the indicated novologue overnight and then subjected to 4 h of hyperglycemia. Cell viability was measured as described in General
Experimental Methods and the data expressed as percent of normoglycemic controls. Under hyperglycemic conditions and in the absence of any
novologues, cell viability was 20% 7. (Right Panel) The EC50 was determined using the ECanything function of GraphPad Prism 5.0, and the mean
SEM (n = 3−8) is shown. #, p < 0.05 versus compound 2.
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developed in which the expression of luciferase is driven by the
human Hsp70 promoter containing two heat shock binding
elements.24 Because primary sensory neurons transfect poorly,
an immortalized sensory neuron cell line (50B11 cells) was
used for transfection.25 Importantly, 50B11 cells have a very
low basal level of Hsp70 expression, similar to primary sensory
neurons.26 Twenty-four hours after transfection with the
reporter, cells were reseeded into 12-well plates and incubated
for an additional 6 h. The cells were then treated for 16 h with
10−1000 nM of the indicated novologues, cell lysates were
prepared, luciferase activity assessed, and luminescence
normalized to total protein per well. Consistent with its
increased efficacy in protecting against glucotoxicity, 13b was
more effective than 2 at activation of the Hsp70 promoter
(Figure 5A) and also increased expression of Hsp70 protein at
lower concentrations relative to compound 2 (Figure 5B).
Although 13i had a similar EC50 as 13b in preventing
glucotoxicity, it only activated the Hsp70 promoter at 1 μM,
and the magnitude of this effect was no better than either 2 or
13b. However, it was surprising that despite the low EC50 of
13n in protecting against glucotoxicity, 13n did not increase
luciferase activity at any concentration tested nor did it increase
Hsp70 protein expression as effectively as 2 or 13b. These
results suggest that 13n likely affects Hsp70 levels indirectly
and that the mechanism for neuroprotection may be distinct
from that of related novologues.
Lastly, we mentioned that an attractive property of the
modified novobiocin scaffold of 2 is that it induces Hsp70 at
concentrations well below those needed to inhibit Hsp90's
protein folding ability.10 Therefore, to confirm that this new
scaffold manifests similar activity, 13b was evaluated against
MCF-7 breast cancer cells that are highly reliant upon the
Hsp90 protein folding machinery. As can be observed, no client
protein degradation occurred at concentrations up to 5 μM,
indicating the potential for a large therapeutic window for this
scaffold as well.
Figure 5. Induction of Hsp70 by select novologues in the absence of
client protein degradation. (A) 50B11 cells were transfected with a
luciferase reporter whose expression was drive by the human Hsp70
promoter. The cells were treated with the indicated concentration of
select novologues for 16 h and luciferase activity assessed. **, p < 0.01
and ***, p < 0.001 versus control; ∧ p < 0.05 and ∧∧∧, p < 0.001 versus
compound 2 at same concentration. (B) DRG sensory neurons were
incubated in the presence of DMSO (Cntrl) or 10−1000 nM of the
indicated novologue overnight and then subjected to 4 h of
hyperglycemia. The neurons were harvested and Hsp70, and β-actin
levels were determined by immunoblot analysis. Band intensity was
quantified using Image J, Hsp70 expression was normalized to the level
of β-actin and expressed as a fold control. (C) MCF7 cells were
treated with the indicated concentrations of 13b for 24 h, cell lysates
were prepared, and the levels of the Hsp90 client proteins, Her2, Raf,
and Akt determined by immunoblot analysis. As a positive control,
some cells were treated with 500 nM geldanamycin (GDA) to induce
client protein degradation. The level of β-actin verified equivalent
protein loading.
CONCLUSION
■
Using the recently reported model for the Hsp90 C-terminal
binding site, a novologue scaffold was designed to afford
putative interactions with previously unoccupied regions of the
binding pocket, including Lys539. Through systematic
replacement of substituents on the novologue B-ring (see
Table 2), compound 13b was identified as a neuroprotective
agent that exhibited ∼14-fold greater efficacy against glucose-
induced toxicity than the lead compound 2. The concentration
of 13b needed to manifest neuroprotective activity correlated
well with its ability to induce Hsp70 levels, therefore linking
cytoprotection to Hsp70 induction. When combined, these
data demonstrate the rationally designed novologue scaffold
provides a promising platform on which diversification of the B-
ring can lead to compounds that exhibit better neuroprotective
activities than first generation analogues.
100 U/mL penicillin, and 100 μg/mL streptomycin) and triturated
with a fire-polished glass pipet. The cells were cultured on collagen-
coated (0.1 mg/mL collagen followed by overnight air drying in a
laminar flow hood) black-walled 96-well plates (Corning Incorporated
Corning, NY) at a seeding density of (2−3) × 104 cells per well. DRG
neurons were refed the next day with fresh growth media containing
40 μM fluorodeoxyuridine and 10 μM cytosine β-D-arabinoside (both
from Sigma Aldrich, St. Louis, MO) for 2 days to remove proliferating
cells. Experiments were performed on DRG neurons on the third day
in culture after placing the cells in fresh growth medium.
Glucotoxicity Assay. As immature DRG are susceptible to
hyperglycemia-induced death,27 an additional 20 mM glucose was
added to the growth medium (yielding a total of 45 mM glucose) for 4
h. Preliminary experiments found that 20 mM excess glucose for 4 h
was sufficient to induce a reproducible 40−50% loss in neuronal
viability. As a result, the toxicity induced by the acute change in
GENERAL EXPERIMENTAL METHODS
■
Preparation of Embryonic Dorsal Root Ganglion (DRG)
Neuron Cultures. DRG from embryonic day 15−18 Sprague−
Dawley rat pups were harvested into Leibovitz’s L15 medium (L15)
and dissociated with 0.25% trypsin for 30 min at 37 °C. The ganglia
were sedimented at 1000g for 5 min, resuspended in growth media
(phenol red free Neurobasal medium (Gibco, Grand Island, NY)
containing 25 mM glucose, 1× B-27 additive, 50 ng/mL nerve growth
factor (NGF) (Harlan Bioscience, Indianapolis, IN), 4 mM glutamine,
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then docked with 10 different starting conformations while rotation of
rotatable bonds was unrestricted. Visual interpretation and figure
preparation were then carried out in Pymol.
Table 2. Cell Viability Data of Cyclohexene Containing
Analogues
1
Chemistry General. H NMR were recorded at 400 or 500 MHz
(Bruker DRX-400 Bruker with a H/C/P/F QNP gradient probe)
spectrometer and 13C NMR spectra were recorded at 125 MHz
(Bruker DRX 500 with broadband, inverse triple resonance, and high
resolution magic angle spinning HR-MA probe spectrometer);
chemical shifts are reported in δ (ppm) relative to the internal
reference chloroform-d (CDCl3, 7.27 ppm). FAB (HRMS) spectra
were recorded with a LCT Premier (Waters Corp., Milford, MA). The
purity of all compounds was determined to be >95% as determined by
1H NMR and 13C NMR spectra, unless otherwise noted. The most
active five compounds were verified for >95% purity by HPLC
analyses. TLC was performed on glass backed silica gel plates
(Uniplate) with spots visualized by UV light. All solvents were reagent
grade and, when necessary, were purified and dried by standard
methods. Concentration of solutions after reactions and extractions
involved the use of a rotary evaporator operating at reduced pressure.
5-(Benzyloxy)-2-formylphenyl trifluoromethanesulfonate
(7). Triethylamine (1.02 mL, 7.35 mmol) followed by triflic anhydride
(1.38 mL, 6.35 mmol) were added simultaneously to a phenol 6 (1.12
g, 4.91 mmol) in anhydrous CH2Cl2 (10 mL) at 0 °C. Upon
completion of the reaction, quenched by the addition of water (50
mL), extracted with CH2Cl2 (3 × 15 mL), washed with saturated
aqueous sodium chloride solution, dried over anhydrous Na2SO4,
filtered, and concentrated. The residue was purified by column
chromatography (SiO2, 4:1, Hex:EtOAc) to afford triflate 7 as a yellow
oil (1.06 g, 60%).
a
entry
R
% of cell viability
86
78 18#
2
2
b
22a
22b
F
b,c
CF3
69 15#,*
a
In the presence of 1 μM novologue +20 mM excess glucose. Viability
in the presence of 20 mM excess glucose + DMSO was 54% 2. #, p
< 0.05 versus glucose + DMSO. *, p < 0.05 versus glucose + 2 (n = 8)
b
c
per novologue.
glucose concentration makes it a useful model for drug screening.10,28
Given the short time frame that the neurons are grown in vitro, they
are not pure neuronal cultures but instead highly enriched.
Importantly, the contaminating SCs that remain in the culture are
resistant to glucose-induced death as we and others have reported
previously.6 Unfortunately, the use of highly purified cultures is
problematic because the cells extend neurites and establish
connections with each other, thus becoming resistant to hyper-
glycemia-induced death.6a
General Procedure for Suzuki Coupling Reaction of Triflate
3 and Boronic Acids 4a−p. 5-(Benzyloxy)-[1,1′-biphenyl]-2-
carbaldehyde (8a). Tetrakis(triphenylphosphine)palladium(0) (70.4
mg, 0.068 mmol) was added to a mixture of triflate 7 (0.246 g, 0.68
mmol), phenylboronic acid 4a (92 mg, 0.75 mmol), and K2CO3
(0.169 g, 1.2 mmol) in DMF (6.8 mL) under argon atmosphere in a
sealed tube. The resulting reaction mixture was sealed and heated to
reflux for 16 h. The reaction was cooled to room temperature,
quenched with saturated sodium bicarbonate, extracted with EtOAc (3
× 5 mL), washed with saturated aqueous sodium chloride, dried over
anhydrous Na2SO4, filtered, and concentrated. The crude product was
purified by column chromatography (SiO2, 3:1, Hex:EtOAc) to afford
DRG neurons were incubated overnight with the novologues in the
presence of Neurobasal medium, 50 ng/mL NGF, and antibiotics only.
To monitor the efficiency of the novologues in protecting DRG
neurons against glucotoxicity, we made use of Calcein AM (Invitrogen,
Carlsbad, CA) to measure cell viability. Hydrolysis of calcein AM to a
fluorescent product can only occur in live cells. Excess glucose was
added to the cultures for 4 h, and cell viability was measured by
incubating the cells with 2 μM calcein AM for 30 min in the dark at 37
°C. Fluorescence was then measured using a plate reader with
excitation and emission wavelengths set to 485 nm and 520 nm,
respectively. The arbitrary fluorescence readings were normalized to
the total amount of protein from each respective well of the neuronal
cultures. The protein concentrations in each well were determined
using the DC protein assay (Bio-Rad). Significant differences in the
efficacy of the novologues for increasing cell viability were determined
using a Kruskal−Wallis nonparametric ANOVA and Dunn’s post-test.
Luciferase Reporter Assay and Client Protein Degradation.
A 1.5 kb region upstream of the start codon of the human HSPA1A
gene was synthesized by GeneArt (Life Technologies, Grand Island,
NY) and 5′ KpnI and 3′ SacI sites added to direct cloning into the
pGL3 basic luciferase reporter plasmid. DNA sequencing verified the
integrity of the promoter sequence and the presence of two heat shock
elements. 50B11 cells25 were grown in 10 cm dishes in DMEM
containing 25 mM glucose, 10% FCS, and 5 μg/mL blasticidin. The
cells were transfected using lipofectamine and after 24 h were reseeded
into 24 well plates at a density of 2 × 105 cells per well. The cells were
permitted to attach to the plate for 6 h in growth medium and treated
with the indicated concentrations of the various novologues for 16 h.
Luciferase activity was assessed and normalized to the total protein
concentration of each well. Results shown are from triplicate wells
obtained in at least three separate experiments. Preliminary experi-
ments validated that the reporter was strongly activated as expected by
either heat shock (∼10-fold) or 250 nM geldanamycin (∼4−5-fold).
Client protein degradation in MCF7 cells was performed as we have
previously described.10
1
8a (0.16 g, 0.56 mmol, 82%) as an amorphous solid. H NMR (400
MHz, CDCl3) δ 9.90 (s, 1H), 8.08 (d, J = 8.7 Hz, 1H), 7.55−7.34 (m,
10H), 7.11 (d, J = 8.7 Hz, 1H), 7.0 3 (d, J = 2.4 Hz, 1H), 5.19 (s, 2H).
13C NMR (100 MHz, CDCl3) δ 191.2, 162.8, 148.6, 137.8, 136.0,
130.0, 128.8, 128.4, 127.6, 116.3, 114.7, 70.4. HRMS (FAB) m/z [M +
Na+] for C20H16O2Na: calcd, 311.1042; found, 311.1046.
5-(Benzyloxy)-3′-fluoro-[1,1′-biphenyl]-2-carbaldehyde (8b).
1
Using 3-flourophenylboronic acid. H NMR (500 MHz, CDCl3) δ
9.85 (d, J = 0.7 Hz, 1H), 8.03 (d, J = 8.7 Hz, 1H), 7.49−7.33 (m, 6H),
7.20−7.13 (m, 2H), 7.13−7.08 (m, 2H), 7.03 (d, J = 2.5 Hz, 1H), 5.15
(s, 2H). 13C NMR (125 MHz, CDCl3) δ 190.7, 162.9, 161.7, 147.2,
140.1, 136.0, 130.5, 129.0, 128.6, 127.8, 126.0, 117.1, 116.9, 116.4,
115.5, 115.1, 70.6. HRMS m/z [M + Na+] for C20H15FO2Na: calcd,
329.0948; found, 329.0952.
5-(Benzyloxy)-4′-fluoro-[1,1′-biphenyl]-2-carbaldehyde (8c).
1
Using 4-flourophenylboronic acid. H NMR (400 MHz, CDCl3) δ
9.84 (s, 1H), 8.06 (dd, J = 8.7, 1.0 Hz, 1H), 7.49−7.40 (m, 4H), 7.40−
7.32 (m, 3H), 7.21−7.13 (m, 2H), 7.12−7.06 (dd, J = 8.0, 2.5 Hz,
1H), 7.03 (d, J = 2.2 Hz, 1H), 5.17 (s, 2H). 13C NMR (100 MHz,
CDCl3) δ 190.9, 162.8, 147.4, 136.0, 131.7, 131.6, 130.5, 128.8, 128.5,
127.7, 127.6, 116.5, 115.6, 115.4, 114.7, 70.4. HRMS m/z [M + Na+]
for C20H15FO2Na: calcd, 329.0948; found, 329.0944.
5-(Benzyloxy)-2′-chloro-[1,1′-biphenyl]-2-carbaldehyde (8d).
1
Using 2-chlorophenylboronic acid. H NMR (500 MHz, CDCl3) δ
Molecular Modeling. Surflex-Dock in Sybyl v8.0 was used for
molecular modeling and docking studies. A homology model of
Hsp90α based on the open HtpG SAXS structure was used as the
receptor, while the protomol was generated using docked Novobiocin
as described in reference.13 The energy minimized molecules were
9.70 (s, 1H), 8.08 (d, J = 8.7 Hz, 1H), 7.55−7.49 (m, 1H), 7.49−7.32
(m, 8H), 7.17−7.12 (dd, J = 8.6, 2.5 Hz, 1H), 6.99 (d, J = 2.6 Hz, 1H),
5.16 (s, 2H). 13C NMR (125 MHz, CDCl3) δ 190.3, 162.9, 145.1,
136.8, 135.9, 133.5, 131.6, 130.0, 129.8, 129.6, 128.8, 128.4, 127.6,
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Journal of Medicinal Chemistry
Article
127.6, 126.9, 116.7, 115.1, 70.4. HRMS m/z [M + Na+] for
C20H15ClO2Na, calcd, 345.0658; found, 345.0653.
5-(Benzyloxy)-4′-hydroxy-[1,1′-biphenyl]-2-carbaldehyde (8m).
Used 4-hydroxyphenylboronic acid. Partially purified biaryl phenol
was treated with TBSCl (1.2 equiv) and imidazole (3 equiv) in
CH2Cl2 and stirred for 2 h at room temperature. After reaction was
completed by TLC, the resulting reaction mixture was concentrated.
The crude product was purified by column chromatography (SiO2,
4:1, Hex:EtOAc) to afford 8m (94%) as an amorphous solid. 1H NMR
(500 MHz, CDCl3) δ 9.89 (s, 1H), 8.03 (d, J = 8.7 Hz, 1H), 7.52−
7.33 (m, 5H), 7.26 (dd, J = 6.6, 1.8 Hz, 2H), 7.05 (dd, J = 8.7, 2.3 Hz,
1H), 7.02−6.93 (m, 3H), 5.17 (s, 2H), 1.05 (s, 9H), 0.29 (s, 6H). 13C
NMR (125 MHz, CDCl3) δ 191.2, 162.7, 156.0, 148.4, 136.1, 131.2,
130.6, 130.0, 128.7, 128.3, 127.6, 127.5, 120.0, 116.1, 114.3, 70.3, 25.7,
18.3, 4.3. ESI-HRMS m/z [M + Na]+ for C26H30NaO3Si: calcd,
441.5899, found 441.5896.
5-(Benzyloxy)-3′-chloro-[1,1′-biphenyl]-2-carbaldehyde (8e).
1
Using 3-chlorophenylboronic acid. H NMR (400 MHz, CDCl3) δ
9.85 (s, 1H), 8.04 (d, J = 8.7 Hz, 1H), 7.49−7.33 (m, 8H), 7.26 (m,
1H), 7.13−7.07 (dd, J = 8.3, 2.8 Hz, 1H), 6.96 (d, J = 2.5 Hz, 1H),
5.17 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 190.4, 162.8, 146.8,
139.7, 135.9, 134.5, 130.5, 129.8, 129.7, 128.8, 128.5, 128.4, 128.3,
127.6, 127.5, 116.3, 115.0, 70.4. HRMS m/z [M + Cl−] for
C20H15Cl2O2: calcd, 341.0505; found, 341.0508.
5-(Benzyloxy)-3′-(trifluoromethyl)-[1,1′-biphenyl]-2-carbalde-
hyde (8f). Using 3-(trifluoromethyl)phenylboronic acid. 1H NMR
(400 MHz, CDCl3) δ 9.82 (s, 1H), 8.05 (m, 1H), 7.72 (m, 1H), 7.67−
7.64 (td, J = 1.6, 0.8 Hz, 1H), 7.64−7.53 (m, 2H), 7.50−7.35 (m, 5H),
7.15−7.11 (dd, J = 8.7, 2.2 Hz, 1H), 6.96 (d, J = 2.5 Hz, 1H), 5.19 (s,
2H). 13C NMR (100 MHz, CDCl3) δ 190.4, 163.0, 146.8, 138.8, 135.9,
133.4, 131.0, 130.9, 129.0, 129.0, 128.6, 127.8, 127.6, 126.6, 126.5,
125.2, 116.7, 115.2, 70.6. HRMS m/z [M + Na+] for C21H15F3O2Na:
calcd, 379.0922; found, 379.0926.
5-(Benzyloxy)-4′-(trifluoromethyl)-[1,1′-biphenyl]-2-carbalde-
hyde (8g). Using 4-(trifluoromethyl)phenylboronic acid. 1H NMR
(400 MHz, CDCl3) δ 9.84 (s, 1H), 8.06 (d, J = 8.7 Hz, 1H), 7.75 (d, J
= 8.0 Hz, 2H), 7.55−7.49 (m, 2H), 7.49−7.34 (m, 6H), 7.17−7.12
(dd, J = 9.1, 2.2 Hz, 1H), 6.98 (d, J = 2.5 Hz, 1H), 5.19 (s, 2H). 13C
NMR (100 MHz, CDCl3) δ 190.2, 162.9, 146.7, 141.7, 135.9, 130.8,
130.3, 128.9, 128.6, 127.7, 127.5, 125.5, 125.4, 122.8, 116.6, 115.1,
70.5. HRMS m/z [M + H+] for C21H16F3O2: calcd, 357.1097; found,
357.1096.
2-(Benzo[d][1,3]dioxol-5-yl)-4-(benzyloxy)benzaldehyde (8n).
Using 3,4-(methylenedioxy)phenylboronic acid. 1H NMR (500
MHz, CDCl3) δ 9.90 (s, 1H), 8.08 (d, J = 8.7 Hz, 1H), 7.48−7.39
(m, 4H), 7.39−7.35 (m, 1H), 7.06 (d, J = 8.6 Hz, 1H), 6.97 (d, J = 2.5
Hz, 1H), 6.91−6.86 (m, 2H), 6.83−6.79 (m, 1H), 6.03 (s, 2H), 5.15
(s, 2H). 13C NMR (125 MHz, CDCl3) δ 191.2, 162.8, 148.2, 147.9,
147.9, 136.1, 131.6, 130.2, 128.8, 128.4, 127.7, 127.6, 124.0, 116.2,
114.5, 110.3, 108.3, 101.5, 70.4. HRMS (FAB) m/z [M + Na+] for
C21H16O4Na: calcd, 355.0941; found, 355.0935.
1
4-(Benzyloxy)-2-(pyridin-3-yl)benzaldehyde (8o). H NMR (400
MHz, CDCl3) δ 9.79 (s, 1H), 8.65 (dd, 2H, J = 5.1, 8.3 Hz), 8.01 (d,
1H, J = 8.8 Hz), 7.67 (m, 1H), 7.48−7.26 (m, 6H), 7.09 (dd, 1H, J =
2.4, 8.7 Hz), 6.93 (d, 1H, J = 2.4 Hz), 5.14 (s, 2H). 13C NMR (125
MHz, CDCl3) δ 187.8, 165.3, 160.5, 135.8, 131.2, 129.0, 128.7, 127.8,
120.0, 109.5, 102.1, 91.0, 70.8. HRMS (FAB) m/z [M + H+] for
C19H16NO2: calcd, 290.1181; found, 290.1177.
5-(Benzyloxy)-2′-(methylthio)-[1,1′-biphenyl]-2-carbaldehyde
1
(8h). Using 2-(methylthio)phenylboronic acid. H NMR (400 MHz,
1
CDCl3) δ 9.62 (s, 1H), 8.05 (d, J = 8.7 Hz, 1H), 7.47−7.32 (m, 6H),
7.30−7.23 (m, 2H), 7.24−7.20 (m, 1H), 7.13−7.09 (m, 1H), 6.93−
6.90 (m, 1H), 5.17 (s, 2H), 2.36 (d, J = 1.1 Hz, 3H). 13C NMR (100
MHz, CDCl3) δ 190.8, 163., 146.3, 138.4, 136.2, 136.1, 130.4, 129.5,
129.1, 128.8, 128.4, 127.8, 127.7, 124.7, 124.6, 116.4, 115.3, 70.4, 15.6.
HRMS m/z [M + H+] for C21H18O2SNa: calcd, 357.0920; found,
357.0923.
4-(Benzyloxy)-2-(pyridin-4-yl)benzaldehyde (8p). H NMR (500
MHz, CDCl3) δ 9.82 (s, 1H), 8.67 (d, J = 5.9 Hz, 2H), 8.02 (d, J = 8.7
Hz, 1H), 7.49−7.33 (m, 6H), 7.30 (d, J = 6.0 Hz, 1H), 7.15−7.10 (dd,
J = 8.6, 2.6 Hz, 1H), 6.95 (d, J = 2.6 Hz, 1H), 5.15 (s, 2H). 13C NMR
(125 MHz, CDCl3) δ 189.7, 162.9, 149.8, 145.8, 145.2, 135.7, 131.0,
128.8, 128.5, 127.6, 127.1, 124.6, 116.3, 115.4, 70.5. HRMS (FAB) m/
z [M + H+] for C19H16NO2: calcd, 290.1181; found, 290.1183.
General Procedure for Henry Reaction of Compounds 8a−p.
(E)-5-(Benzyloxy)-2-(2-nitrovinyl)-1,1′-biphenyl (9a). Nitromethane
(1.4 mL) was added to a mixture of aldehyde 8a (0.16 g, 0.56 mmol)
and ammonium acetate (77 mg, 1.0 mmol) and heated to 50 °C. Upon
completion (∼15−30 min), the reaction mixture was cooled to RT
and purified without workup by column chromatography (SiO2, 3:1,
Hex:EtOAc) to afford nitrostyrene 9a as a yellow oil (182 mg, 0.55
5-(Benzyloxy)-2′-methoxy-[1,1′-biphenyl]-2-carbaldehyde (8i).
1
Using 2-methoxyphenylboronic acid. H NMR (500 MHz, CDCl3)
δ 9.73 (s, 1H), 8.07 (d, J = 8.7 Hz, 1H), 7.48−7.39 (m, 5H), 7.37 (d, J
= 6.5 Hz, 1H), 7.32−7.27 (m, 1H), 7.13−7.07 (m, 2H), 7.02 (d, J =
8.3 Hz, 1H), 6.98−6.95 (dd, J = 2.4, 1.1 Hz, 1H), 5.15 (s, 2H), 3.75 (s,
3H). 13C NMR (125 MHz, CDCl3) δ 191.5, 163.1, 156.6, 144.5, 136.2,
131.4, 130.1, 129.2, 128.8, 128.4, 127.9, 127.7, 126.8, 121.0, 116.9,
114.5, 110.8, 70.3, 55.5. HRMS m/z [M + H+] for C21H19O3: calcd,
319.1329; found, 319.1333.
1
mmol, 98%). H NMR (400 MHz, CDCl3) δ 8.02 (d, J = 13.6 Hz,
1H), 7.64 (d, J = 9.5 Hz, 1H), 7.50−7.35 (m, 10H), 7.31(d, J = 2.1 Hz,
2H), 7.04 (d, J = 2.5 Hz, 1H), 5.15 (s, 2H). 13C NMR (100 MHz,
CDCl3) δ 161.8, 146.1, 138.1, 136.4, 136.3, 135.5, 131.8 131.7, 129.9,
129.2, 128.8, 128.0, 121.3, 117.3, 116.3, 116.0, 115.6, 70.7. HRMS
(FAB) m/z [M + Na+] for C21H18NO3: calcd, 332.1281; found,
332.1290.
5-(Benzyloxy)-3′-methoxy-[1,1′-biphenyl]-2-carbaldehyde (8j).
1
Using 3-methoxyphenylboronic acid. H NMR (400 MHz, CDCl3)
δ 9.93 (s, 1H), 8.06 (d, J = 9.0 Hz, 1H), 7.52−7.35 (m, 6H), 7.10 (d, J
= 8.6 Hz, 1H), 7.05−6.93 (m, 4H), 5.20 (s, 2H), 3.89 (s, 3H). HRMS
m/z [M + Na+] for C21H18O3Na: calcd, 341.1154; found, 341.1150.
5-(Benzyloxy)-3′-methyl-[1,1′-biphenyl]-2-carbaldehyde (8k).
1
(E)-5-(Benzyloxy)-3′-fluoro-2-(2-nitrovinyl)-1,1′-biphenyl (9b). H
1
NMR (400 MHz, CDCl3) δ 8.07 (d, J = 13.5 Hz, 1H), 7.65 (d, J = 8.7
Hz, 1H), 7.49−7.35 (m, 7H), 7.20−7.13 (ddd, J = 9.3, 7.9, 2.6 Hz,
1H), 7.09−7.03 (m, 2H), 7.02 (d, J = 2.8 Hz, 2H), 5.16 (s, 2H). 13C
NMR (100 MHz, CDCl3) δ 164.0, 161.5, 145.4, 141.4, 137.6, 136.1,
136.0, 130.5, 130.4, 129.6, 128.6, 127.7, 125.7, 121.0, 116.9, 116.6,
115.6, 115.4, 70.5. HRMS m/z [M + H+] for C21H17FNO3: calcd,
350.1187; found, 350.1185.
Using 3-methylphenylboronic acid. H NMR (500 MHz, CDCl3) δ
9.85 (d, J = 0.9 Hz, 1H), 8.03 (d, J = 8.6 Hz, 1H), 7.49−7.39 (m, 3H),
7.39−7.32 (m, 2H), 7.27 (d, J = 8.1 Hz, 1H), 7.22−7.16 (m, 2H),
7.09−7.05 (ddd, J = 8.8, 2.6, 0.9 Hz, 1H), 6.98 (d, J = 2.5 Hz, 1H),
5.15 (s, 2H), 2.43 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 191.4,
162.8, 148.9, 138.3, 137.9, 136.2, 130.9, 130.1, 129.2, 128.9, 128.5,
128.5, 127.8, 127.3, 116.3, 114.8, 70.5, 21.7. HRMS m/z [M + H+] for
C21H18O2Na: calcd, 325.1205; found, 325.1217.
1
(E)-5-(Benzyloxy)-4′-fluoro-2-(2-nitrovinyl)-1,1′-biphenyl (9c). H
NMR (400 MHz, CDCl3) δ 8.08 (d, J = 13.6 Hz, 1H), 7.64 (d, J = 8.7
Hz, 1H), 7.50−7.34 (m, 6H), 7.32−7.24 (m, 2H), 7.23−7.14 (t, J =
8.3 Hz, 2H), 7.10−7.00 (m, 2H), 5.17 (s, 2H). 13C NMR (100 MHz,
CDCl3) δ 161.5, 145.7, 137.8, 136.1, 136.0, 131.5, 131.4, 129.6, 128.9,
128.5, 127.7, 121.0, 117.0, 115.9, 115.7, 115.3, 70.4. HRMS m/z [M +
Na+] for C21H16FNO3Na: calcd, 372.1006; found, 372.1011.
5-(Benzyloxy)-3′-(morpholinomethyl)-[1,1′-biphenyl]-2-carbalde-
hyde (8l). Using 3-(4-morpholinomethyl)phenylboronic acid pinacol
ester. 1H NMR (400 MHz, CDCl3) δ 9.87 (s, 1H), 8.83 (d, J = 8.7 Hz,
1H), 7.47−7.31 (m, 7H), 7.32−7.24 (m, 1H), 7.12−7.04 (dd, J = 8.7,
2.5 Hz, 1H), 7.05 (d, J = 2.5 Hz, 1H), 5.17 (s, 2H), 3.79−3.68 (t, J =
4.6 Hz, 4H), 3.56 (s, 3H), 2.49 (d, J = 6.5 Hz, 4H). 13C NMR (100
MHz, CDCl3) δ 191.0, 162.7, 148.5, 138.3, 137.8, 136.0, 130.7, 130.2,
129.1, 128.8, 128.4, 127.6, 127.6, 116.4, 114.5, 70.4, 67.1, 63.2, 53.7.
HRMS m/z [M + Na+] for C25H25NO3Na, calcd: 410.1726; found,
410.1730.
(E)-5-(Benzyloxy)-2′-chloro-2-(2-nitrovinyl)-1,1′-biphenyl (9d). 1H
NMR (500 MHz, CDCl3) δ 7.85−7.75 (m, 1H), 7.74−7.66 (m, 1H),
7.55 (m, 1H), 7.53−7.34 (m, 8H), 7.31 (d, J = 5.3 Hz, 1H), 7.17 (d, J
= 8.3 Hz, 1H), 7.01 (t, J = 2.0 Hz, 1H), 5.20−5.11 (m, 2H). 13C NMR
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(125 MHz, CDCl3) δ 161.4, 143.8, 137.7, 137.0, 135.9, 133.2, 131.4,
130.0, 130.0, 129.3, 128.7, 128.3, 127.6, 127.1, 123.4, 121.5, 117.1,
115.6, 70.3. HRMS m/z [M + H+] for C21H17ClNO3: calcd, 366.0892;
found, 366.0895.
63.3, 53.8. HRMS m/z [M + H+] for C26H27N2O4: calcd, 431.1971;
found, 431.1974.
(E)-((5′-(Benzyloxy)-2′-(2-nitrovinyl)-[1,1′-biphenyl]-4-yl)oxy)-
(tert-butyl)dimethylsilane (9m). 1H NMR (400 MHz, CDCl3) δ 8.03
(d, J = 13.7 Hz, 1H), 7.61 (d, J = 8.3 Hz, 1H), 7.49−7.33 (m, 6H),
7.17 (d, J = 8.4 Hz, 2H), 7.02 (s, 2H), 6.95 (d, J = 8.5 Hz, 2H), 5.15
(s, 2H), 1.04 (s, 9H), 0.30 (s, 6H). 13C NMR (100 MHz, CDCl3) δ
161.5, 156.2, 146.8, 138.5, 136.2, 135.8, 132.2, 131.0, 129.6, 128.9,
128.5, 127.7, 121.1, 120.4, 116.8, 115.0, 70.4, 25.9, 18.4, −4.1. HRMS
(FAB) m/z [M + Na+] for C27H31NO4SiNa: calcd, 484.1914; found,
484.1936.
5-(Benzyloxy)-3′-chloro-2-(2-nitrovinyl)-1,1′-biphenyl (9e). 1H
NMR (400 MHz, CDCl3) δ 7.95 (d, J = 13.5 Hz, 1H), 7.64 (d, J =
8.8 Hz, 1H), 7.50−7.36 (m, 8H), 7.33 (s, 1H), 7.18 (d, J = 7.0 Hz,
1H), 7.09−7.04 (m, 1H), 7.00 (d, J = 2.6 Hz, 1H), 5.17 (s, 2H). 13C
NMR (125 MHz, CDCl3) δ 145.1, 141.1, 140.9, 137.4, 136.1, 134.7,
129.9, 129.6, 129.6, 129.5, 129.0, 128.8, 128.5, 128.4, 128,0, 127.6,
120.9, 116.9, 115.5, 109.9, 70.4. HRMS m/z [M + Cl−] for
C21H16Cl2NO3: calcd, 400.0513; found, 400.0505.
(E)-5-(5-(Benzyloxy)-2-(2-nitrovinyl)phenyl)benzo[d][1,3]dioxole
1
(9n). H NMR (400 MHz, CDCl3) δ 8.03 (d, J = 13.6 Hz, 1H), 7.59
(E)-5-(Benzyloxy)-2-(2-nitrovinyl)-3′-(trifluoromethyl)-1,1′-bi-
phenyl (9f). 1H NMR (400 MHz, CDCl3) δ 7.90 (d, J = 13.5 Hz, 1H),
7.78−7.70 (m, 1H), 7.69−7.55 (m, 3H), 7.51−7.34 (m, 7H), 7.13−
7.05 (dd, J = 8.8, 2.6 Hz, 1H), 7.02 (d, J = 2.6 Hz, 1H), 5.17 (s, 2H).
13C NMR (100 MHz, CDCl3) δ 161.6, 155.7, 152.1, 145.1, 140.6,
140.0, 137.2, 136.4, 136.0, 133.2, 129.7, 129.3, 129.0, 128.6, 127.7,
121.0, 117.1, 115.8, 70.6. HRMS m/z [M + H+] for C22H17F3NO3:
calcd, 400.1161; found, 400.1157.
(d, J = 8.0 Hz, 1H), 7.50−7.33 (m, 6H), 7.05−6.98 (m, 2H), 6.92−
6.85 (m, 1H), 6.79 (s, 1H), 6.71(d, J = 7.9 Hz, 1H), 6.03 (s, 2H), 5.17
(s, 2H). 13C NMR (100 MHz, CDCl3) δ 161.4, 148.0, 147.9, 146.5,
138.1, 136.1, 135.7, 132.9, 129.5, 128.8, 128.4, 127.6, 123.6, 121.0,
116.7, 115.0, 109.9, 108.5, 101.5, 70.3. HRMS (FAB) m/z [M + H+]
for C22H18NO5: calcd, 376.1185; found, 376.1160.
(E)-3-(5-(Benzyloxy)-2-(2-nitrovinyl)phenyl)pyridine (9o). 1H
NMR (400 MHz, CDCl3) δ 8.70 (dd, J = 4.8, 1.6 Hz, 1H), 8.59 (d,
J = 1.6 Hz, 1H), 7.89 (d, J = 13.5 Hz, 1H), 7.68−7.60 (m, 2H), 7.47−
7.32 (m, 8H), 7.12−7.06 (dd, J = 8.7, 2.5 Hz, 1H), 7.00 (d, J = 2.6 Hz,
1H), 5.15 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 161.5, 149.9,
149.6, 142.8, 136.9, 136.8, 136.3, 135.8, 134.8, 129.7, 128.8, 128.5,
127.6, 123.4, 121.1, 117.1, 115.8, 70.4. HRMS (FAB) m/z [M + Na+]
for C20H17N2O3: 333.1239; found, 333.1234.
(E)-5-(Benzyloxy)-2-(2-nitrovinyl)-4′-(trifluoromethyl)-1,1′-bi-
1
phenyl (9g). Pushed through plug of SiO2. TS1−189: H NMR (400
MHz, CDCl3) δ 7.98−7.90 (m, 1H), 7.80 (d, J = 8.0 Hz, 2H), 7.68 (d,
J = 8.8 Hz, 1H), 7.52−7.37 (m, 8H), 7.11 (d, J = 8.8 Hz, 1H), 7.04 (s,
1H), 5.19 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 161.4, 147.8,
144.9, 144.3, 139.8, 138.6, 137.1, 136.4, 135.8, 133.5, 131.2, 129.5,
129.1, 128.8, 128.5, 127.6, 124.2, 120.8, 120.4, 117.0, 115.6, 70.4.
HRMS m/z [M + H+] for C22H17F3NO3: calcd, 400.1155; found,
400.1151.
(E)-4-(5-(Benzyloxy)-2-(2-nitrovinyl)phenyl)pyridine (9p). 1H
NMR (500 MHz, CDCl3) δ 8.74 (dd, 2H, J = 1.6, 4.4 Hz), 7.91 (d,
1H, J = 13.6 Hz), 7.67 (d, 1H, J = 8.8 Hz), 7.48 (d, 1H, J = 13.4 Hz),
7.41 (m, 5H), 7.25 (dd, 2H, J = 1.6, 4.4 Hz), 7.11 (dd, 1H, J = 2.6, 8.7
Hz), 7.01 (d, 1H, J = 2.5 Hz), 5.17 (s, 2H). 13C NMR (125 MHz,
CDCl3) δ 161.2, 150.2, 147.0, 143.7, 136.7, 136.6, 135.8, 128.9, 127.6,
124.5, 120.7, 116.8, 116.1, 70.6. ESI-HRMS m/z [M + H]+calcd for
C20H17N2O3: 333.1239, found 333.1249.
(E)-(5′-(Benzyloxy)-2′-(2-nitrovinyl)-[1,1′-biphenyl]-2-yl)(methyl)-
1
sulfane (9h). H NMR (400 MHz, CDCl3) δ 7.71 (d, J = 13.6 Hz,
1H), 7.62 (d, J = 8.6 Hz, 1H), 7.45−7.31 (m, 7H), 7.31−7.29 (m,
1H), 7.25−7.19 (t, J = 7.2 Hz, 1H), 7.13−6.99 (m, 2H), 6.95 (d, J =
2.8 Hz, 1H), 5.09 (s, 2H), 2.35 (s, 3H). 13C NMR (100 MHz, CDCl3)
δ 161.5, 144.9, 138.0, 137.5, 137.2, 136.1, 135.7, 130.0, 129.4, 129.3,
128.8, 128.4, 127.7, 125.0, 124.9, 121.6, 117.0, 115.8, 70.3, 15.6.
HRMS m/z [M + K+] for C22H19NO3SK: calcd, 416.0718; found,
416.0756.
(E)-5-(Benzyloxy)-2′-methoxy-2-(2-nitrovinyl)-1,1′-biphenyl (9i).
1H NMR (500 MHz, CDCl3) δ 7.86 (d, J = 13.8 Hz, 1H), 7.65 (d,
J = 8.7 Hz, 1H), 7.57−7.34 (m, 7H), 7.24−7.17 (m, 1H), 7.16−6.99
(m, 4H), 5.15 (s, 2H), 3.74 (s, 3H). 13C NMR (125 MHz, CDCl3) δ
161.6, 156.4, 143.7, 138.8, 136.3, 135.3, 131.4, 130.4, 128.9, 128.4,
127.7, 122.0, 121.1, 117.5, 115.1, 111.4, 70.4, 55.6. HRMS m/z [M +
H+] for C22H19NO4: calcd, 362.1387; found, 362.1389.
(E)-5-(Benzyloxy)-3′-methoxy-2-(2-nitrovinyl)-1,1′-biphenyl (9j).
1H NMR (500 MHz, CDCl3) δ 8.04 (d, J = 13.6 Hz, 1H), 7.62 (d,
J = 9.5 Hz, 1H), 7.46−7.37 (m, 6H), 7.07−7.02 (m, 3H), 7.02−6.97
(ddd, J = 8.2, 2.6, 0.9 Hz, 1H), 6.88−6.84 (m, 1H), 6.84−6.80 (dd, J =
2.6, 1.6 Hz, 1H), 5.15 (s, 2H), 3.85 (s, 3H). 13C NMR (125 MHz,
CDCl3) δ 161.5, 159.8, 146.8, 140.6, 138.2, 136.2, 135.9, 129.9, 129.5,
129.0, 128.6, 127.7, 122.3, 121.1, 116.8, 115.4, 115.4, 114.1, 70.5, 55.6.
HRMS m/z [M + Na+] for C22H19NO4Na: 384.1212; found,
384.1218.
General Procedure for Preparation of 10a−p from 9a−p. N-
(2-(5-(Benzyloxy)-[1,1′-biphenyl]-2-yl)ethyl)acetamide (10a). Nitro-
styrene 9a (182 mg, 0.55 mmol) in THF (0.7 mL) was added
dropwise to a solution of lithiumaluminium hydride (42 mg, 1.12
mmol) in THF (2 mL) under argon atmosphere at RT. Upon
completion (nearly immediately), the reaction was quenched by the
addition of water (42 μL), 3 M NaOH (42 μL), and water (84 μL).
The resulted mixture was filtered through a plug of Celite, washed with
CH2Cl2, and dried over K2CO3. Upon filtration, the mixture was
concentrated to oil and used without further purification. Acetic
anhydride (58 μL, 0.62 mmol) and triethylamine (93 μL, 0.67 mmol)
were added to a solution of the crude amine in CH2Cl2 (5.6 mL)
under an organ atmosphere at RT. After 3 h, the reaction was
quenched with saturated aqueous ammonium chloride and extracted
with CH2Cl2 (3 × 10 mL); combined organic fractions were washed
with saturated aqueous sodium chloride, dried over Na2SO4, filtered,
and concentrated. The residue was purified by column chromatog-
raphy (SiO2; 3:1, Hex:EtOAc) to afford acetamide 10a (0.12 g, 0.35
1
mmol, 64%). H NMR (400 MHz, CDCl3) δ 7.50−7.38 (m, 8H),
(E)-5-(Benzyloxy)-3′-methyl-2-(2-nitrovinyl)-1,1′-biphenyl (9k).
7.38−7.30 (m, 2H), 7.23 (d, J = 8.4 Hz, 1H), 7.01−6.95 (dd, J = 8.4,
2.7 Hz, 1H), 6.93 (d, J = 2.7 Hz, 1H), 5.71 (br s, NH), 5.08 (s, 2H),
3.42−3.16 (q, J = 7.0 Hz, 2H), 2.89−2.64 (t, J = 7.2 Hz, 2H), 1.85 (s,
3H). 13C NMR (100 MHz, CDCl3) δ 170.2, 157.2, 143.4, 141.4, 137.0,
130.8, 129.1, 128.7, 128.6, 128.4, 128.0, 127.6, 127.2, 116.6, 114.2,
70.1, 40.7, 31.9, 23.2. HRMS m/z [M + K+] for C23H23NO2K: calcd,
384.1361; found, 384.1359.
1H NMR (500 MHz, CDCl3) δ 8.01 (d, J = 13.6 Hz, 1H), 7.62 (m,
1H), 7.48−7.39 (m, 7H), 7.39−7.33 (t, J = 7.7 Hz, 1H), 7.14−7.07
(m, 2H), 7.05−6.99 (m, 2H), 5.15 (s, 2H), 2.43 (s, 3H). 13C NMR
(125 MHz, CDCl3) δ 138.4, 135.8, 130.4, 129.5, 129.3, 128.9, 128.7,
128.5, 127.8, 127.8, 126.9, 121.1, 116.8, 115.3, 77.5, 77.4, 77.2, 77.0,
70.5 21.7. HRMS m/z [M + Na+] for C22H19NO3N: calcd, 368.1263;
found, 368.1257.
(E)-4-((5′-(Benzyloxy)-2′-(2-nitrovinyl)-[1,1′-biphenyl]-3-yl)-
methyl)morpholine (9l). 1H NMR (400 MHz, CDCl3) δ 7.98 (d, J =
13.6 Hz, 1H), 7.63 (d, J = 9.5 Hz, 1H), 7.48−7.33 (m, 8H), 7.33 (d, J
= 1.7 Hz, 1H), 7.23−7.20 (dd, J = 6.7, 1.8 Hz, 1H), 7.08−6.99 (m,
2H), 5.15 (d, J = 1.6 Hz, 2H), 3.79−3.67 (t, J = 4.1 Hz, 4H), 3.56 (s,
2H), 2.55−2.40 (dd, J = 5.7, 3.4 Hz, 4H). 13C NMR (100 MHz,
CDCl3) δ 161.5, 146.9, 139.2, 138.5, 138.1, 136.1, 135.8, 130.6, 129.5,
129.3, 128.9, 128.8, 128.5, 128.4, 127.7, 121.0, 116.9, 115.1, 70.4, 67.1,
N-(2-(5-(Benzyloxy)-3′-fluoro-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10b). 1H NMR (400 MHz, CDCl3) δ 7.48−7.30 (m, 6H),
7.24−7.18 (d, J = 8.4 Hz, 1H), 7.12−7.04 (m, 2H), 7.04−6.92 (ddd, J
= 18.6, 8.2, 2.5 Hz, 2H), 6.85 (d, J = 2.7 Hz, 1H), 5.34 (br s, NH),
5.05 (s, 2H), 3.32−3.21 (q, J = 6.4, 5.9 Hz, 2H), 2.79−2.68 (t, J = 7.1
Hz, 2H), 1.86 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 170.3, 157.3,
143.7, 142.2, 136.9, 131.0, 130.1, 123.0, 128.8, 128.6, 128.2, 127.7,
125.0, 116.5, 116.4, 114.6, 114.4, 70.2, 40.8, 32.0, 23.3. HRMS m/z [M
+ H+] for C23H23FNO2: calcd, 364.1713; found, 364.1705.
5805
dx.doi.org/10.1021/jm300544c | J. Med. Chem. 2012, 55, 5797−5812

Journal of Medicinal Chemistry
Article
N-(2-(5-(Benzyloxy)-4′-fluoro-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10c). 1H NMR (400 MHz, CDCl3) δ 7.44−7.31 (m, 6H),
7.27−7.22 (dd, J = 8.4, 5.5 Hz, 1H), 7.21−7.17 (d, J = 8.4 Hz, 1H),
7.12−7.05 (m, 3H), 6.96−6.91 (dd, J = 8.3, 3.0 Hz, 1H), 5.83 (br s,
NH), 5.05 (s, 2H), 3.33−3.15 (q, J = 6.7 Hz, 2H), 2.78−2.66 (t, J =
7.2 Hz, 2H), 1.87 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 170.5,
157.3, 142.4, 137.0, 130.9, 130.8, 130.7, 128.7, 128.7, 128.2, 127.7,
116.8, 115.5, 115.3, 114.3, 70.2, 40.8, 32.0, 23.1. HRMS m/z [M +
Na+] for C23H22FNO2Na: calcd, 386.1527; found, 386.1529.
N-(2-(5-(Benzyloxy)-2′-chloro-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10d). 1H NMR (500 MHz, CDCl3) δ 7.52−7.45 (m, 1H),
7.45−7.40 (m, 2H), 7.40−7.35 (m, 3H), 7.35−7.29 (m, 3H), 7.25−
7.21 (m, 1H), 7.05−6.95 (dd, J = 8.5, 2.8 Hz, 1H), 6.82 (d, J = 2.7 Hz,
1H), 5.93 (d, J = 5.4 Hz, 1H), 5.05 (s, 2H), 3.36−3.19 (ddq, J = 19.3,
13.0, 6.1 Hz, 2H), 2.67−2.49 (m, 2H), 1.93 (s, 3H). 13C NMR (125
MHz, CDCl3) δ 175.7, 171.0, 157.1, 140.4, 139.8, 136.9, 133.1, 131.3,
130.4, 129.6, 129.0, 128.6, 128.0, 127.6, 126.8, 116.4, 114.9, 70.1, 40.3,
31.8, 22.9. HRMS m/z [M + H+] for C23H23ClNO2: calcd, 380.1417;
found, 380.1415.
N-(2-(5-(Benzyloxy)-3′-chloro-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10e). 1H NMR (500 MHz, CDCl3) δ 7.47−7.28 (m, 8H),
7.25−7.17 (m, 2H), 6.99−6.92 (dd, J = 8.5, 2.7 Hz, 1H), 6.84 (d, J =
2.8 Hz, 1H), 5.46 (br s, NH), 5.06 (s, 2H), 3.34−3.25 (m, 2H), 2.83−
2.68 (t, J = 7.3 Hz, 2H), 2.03 (s, 3H). 13C NMR (125 MHz, CDCl3) δ
171.6, 157.5, 143.2, 142.1, 136.9, 134.3, 131.1, 129.9 129.3, 128.8,
128.3, 127.7, 127.6, 127.5, 116.7, 114.8, 70.3, 46.1, 41.3, 31.7, 22.5, 8.8.
HRMS m/z [M + H+] for C23H23ClNO2: calcd, 380.1412; found,
380.1414.
3H). 13C NMR (100 MHz, CDCl3) δ 170.1, 159.5, 157.2, 143.3, 142.9,
137.0, 130.8, 129.5, 128.7, 128.1, 128.1, 127.7, 121.6, 116.5, 114.9,
114.3, 112.7, 70.17, 55.4, 40.8, 32.0, 23.3. HRMS m/z [M + H+] for
C24H25NO3Na: calcd, 398.1732; found, 398.1725.
N-(2-(5-(Benzyloxy)-3′-methyl-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10k). 1H NMR (400 MHz, CDCl3) δ 7.45 (m, 3H), 7.40
(m, 3H), 7.37−7.30 (q, J = 7.7, 7.1 Hz, 1H), 7.21 (d, J = 1.4 Hz, 1H),
7.15−7.10 (m, 2H), 6.96 (d, J = 8.1 Hz, 1H), 6.90 (s, 1H), 5.51 (br s,
NH), 5.08 (s, 2H), 3.34−3.24 (q, J = 6.5 Hz, 2H), 2.83−2.71 (t, J =
7.0 Hz, 2H), 2.41 (s, 3H), 1.84 (s, 3H). 13C NMR (100 MHz, CDCl3)
δ 170.0, 157.2, 143.5, 141.4, 138.0, 137.0, 130.7, 129.9, 128.7, 128.7,
128.3, 128.1, 128.0, 127.6, 126.2, 116.5, 114.2, 70.1, 40.8, 31.9, 23.3,
21.6. ESI-HRMS m/z [M + Na]+ calcd for C24H25NO2Na: 382.1777,
found 382.1770.
N-(2-(5-(Benzyloxy)-3′-(morpholinomethyl)-[1,1′-biphenyl]-2-yl)-
ethyl)acetamide (10l). 1H NMR (400 MHz, CDCl3) δ 7.47−7.30 (m,
7H), 7.28 (s, 1H), 7.24−7.18 (m, 2H), 6.98−6.93 (dd, J = 8.4, 2.8 Hz,
1H), 6.89 (d, J = 2.7 Hz, 1H), 5.40 (s, 1H), 5.05 (s, 2H), 3.75−3.69 (t,
J = 4.7 Hz, 4H), 3.55 (s, 2H), 3.36−3.22 (q, J = 6.9 Hz, 2H), 2.80−
2.68 (t, J = 7.1 Hz, 2H), 2.47 (m, 4H), 1.85 (s, 3H). 13C NMR (100
MHz, CDCl3) δ 170.0, 157.3, 143.4, 141.5, 138.0, 137.1, 130.9, 123.0,
128.7, 128.7, 128.4, 128.2, 128.2, 128.0, 127.7, 116.8, 114.1, 70.2, 67.1,
63.5, 53.8, 40.6, 32.1, 23.4. HRMS m/z [M + H+] for C28H33N2O3:
calcd, 445.2491; found, 445.2494.
N-(2-(5-(Benzyloxy)-4′-((tert-butyldimethylsilyl)oxy)-[1,1′-biphen-
1
yl]-2-yl)ethyl)acetamide (10m). H NMR (500 MHz, CDCl3) δ 7.44
(d, J = 7.5 Hz, 3H), 7.42−7.36 (dt, J = 10.5, 5.7 Hz, 3H), 7.36−7.31
(m, 1H), 7.21−7.14 (m, 3H), 6.94−6.86 (m, 2H), 5.08 (s, 2H), 3.34−
3.23 (q, J = 6.7 Hz, 2H), 2.75 (t, J = 7.1 Hz, 2H), 1.74 (s, 3H), 1.97 (s,
9H), 0.25 (s, 6H). 13C NMR (125 MHz, CDCl3) δ 169.9, 157.3,
155.0, 143.3, 137.2, 134.5, 130.8, 130.2, 128.7, 128.1, 127.7, 120.0,
116.8, 114.0, 70.2, 53.6, 40.7, 32.1, 25.8, 23.4, 18.4, −4.2. HRMS
(FAB) m/z [M + Na+] for C29H37NO3SiNa: calcd, 498.2440; found,
498.2447.
N-(2-(Benzo[d][1,3]dioxol-5-yl)-4-(benzyloxy)phenethyl)-
acetamide (10n). 1H NMR (400 MHz, CDCl3) δ 7.49−7.36 (m, 5H),
7.34 (d, J = 4.4 Hz, 1H), 7.20 (d, J = 8.3 Hz, 1H), 6.96−6.89 (dd, J =
8.4, 2.8 Hz, 1H), 6.90−6.84 (m, 2H), 6.81−6.73 (m, 1H), 6.00 (s,
2H), 5.69−5.60 (t, J = 5.8 Hz, 1H), 5.06 (s, 2H), 3.42−3.16 (m, 2H),
2.93−2.68 (t, J = 7.3 Hz, 2H), 1.87 (s, 3H). 13C NMR (100 MHz,
CDCl3) δ 170.4, 157.2, 147.5, 146.8, 143.0, 137.0, 135.2, 130.8, 129.3,
128.8, 128.1, 127.6, 123.2, 122.4, 116.7, 114.1, 109.7, 108.3, 101.2,
70.1, 40.7, 31.9, 23.2. HRMS (FAB) m/z [M + Na+] for
C24H23NO4Na: 412.1519; found, 412.1524.
N-(2-(5-(Benzyloxy)-3′-(trifluoromethyl)-[1,1′-biphenyl]-2-yl)-
1
ethyl)acetamide (10f). H NMR (400 MHz, CDCl3) δ 7.64 (d, J =
7.7 Hz, 1H), 7.59−7.54 (m, 2H), 7.55−7.49 (t, J = 7.3 Hz, 1H), 7.47−
7.32 (m, 5H), 7.24 (d, J = 8.5 Hz, 1H), 7.01−6.96 (dd, J = 8.5, 2.7 Hz,
1H), 6.87 (d, J = 2.7 Hz, 1H), 5.90 (br s, NH), 5.06 (s, 2H), 3.34−
3.23 (q, J = 6.9 Hz, 2H), 2.79−2.68 (t, J = 7.3 Hz, 2H), 1.99 (s, 3H).
13C NMR (100 MHz, CDCl3) δ 170.7, 157.4, 142.2, 141.9, 136.9,
132.6, 131.1, 129.0, 128.8, 128.5, 128.2, 127.7, 124.2, 116.7, 114.8,
70.3, 40.8 31.9, 23.0. HRMS m/z [M + H+] for C24H23F3NO2: calcd,
414.1676; found, 414.1681.
N-(2-(5-(Benzyloxy)-4′-(trifluoromethyl)-[1,1′-biphenyl]-2-yl)-
1
ethyl)acetamide (10g). H NMR (400 MHz, CDCl3) δ 7.66 (d, J =
8.1 Hz, 2H), 7.46−7.23 (m, 8H), 6.99−6.94 (dd, J = 8.5, 2.7 Hz, 1H),
6.84 (d, J = 2.7 Hz, 1H), 6.03 (t, J = 5.5 Hz, 1H), 5.06 (s, 2H), 3.33−
3.19 (dd, J = 14.3, 6.4 Hz, 2H), 2.76−2.68 (dd, J = 8.3, 6.6 Hz, 2H),
1.85 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 170.3, 157.1, 145.1,
141.8, 136.8, 130.9, 129.5, 129.1, 128.6, 128.6, 127.5, 125.6, 125.2,
125.2, 122.9, 116.4, 114.6, 70.1, 40.6, 31.9. HRMS m/z: [M + Na+] for
C24H22F3NO2Na: calcd, 436.1495; found, 436.1489.
N-(2-(5-(Benzyloxy)-2′-(methylthio)-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10h). 1H NMR (400 MHz, CDCl3) δ 7.48−7.30 (m, 7H),
7.28−7.18 (m, 2H), 7.14 (s, 1H), 7.03−6.98 (ddd, J = 8.5, 2.8, 1.0 Hz,
1H), 6.87−6.83 (m, 1H), 5.63 (br s, NH), 5.05 (s, 2H), 3.43−3.16
(ddt, J = 42.5, 13.3, 6.6 Hz, 2H), 2.66−2.52 (t, J = 6.7 Hz, 2H), 2.39
(d, J = 1.0 Hz, 3H), 1.84 (d, J = 1.0 Hz, 3H). 13C NMR (100 MHz,
CDCl3) δ 170.3, 157.3, 141.1, 139.1, 137.6, 137.0, 130.6, 129.8, 129.4,
128.7, 128.4, 128.1, 127.7, 124.5, 124.0, 116.5, 115.2, 70.2, 40.1, 31.7,
23.3, 15.2. HRMS m/z [M + Na+] for C24H25NO2SNa: calcd,
414.1504; found, 414.1509.
N-(2-(5-(Benzyloxy)-2′-methoxy-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10i). 1H NMR (400 MHz, CDCl3) δ 7.47−7.30 (m, 5H),
7.22 (d, J = 8.5 Hz, 1H), 7.17−7.13 (dd, J = 7.4, 1.9 Hz, 1H), 7.07−
6.95 (m, 4H), 6.85 (d, J = 2.7 Hz, 1H), 5.51 (br s, NH), 5.07 (s, 2H),
3.77 (s, 3H), 3.44−3.18 (m, 2H), 2.68−2.56 (td, J = 6.8, 3.7 Hz, 2H),
1.86 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 170.0, 157.2, 156.4,
139.9, 137.1, 131.2, 130.1, 129.2, 128.7, 128.1, 127.8, 120.9, 116.8,
114.4, 111.2, 70.1, 55.8, 40.4, 31.9, 23.5; .HRMS m/z [M + H+] for
C24H26NO3: calcd, 376.1913; found, 376.1902.
N-(2-(5-(Benzyloxy)-3′-methoxy-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (10j). 1H NMR (400 MHz, CDCl3) δ 7.48−7.36 (m, 4H),
7.36−7.30 (m, 3H), 7.21 (d, J = 8.4 Hz, 1H), 6.98−6.92 (m, 1H),
6.92−6.82 (m, 3H), 5.49 (br s, NH), 5.06 (s, 2H), 3.85 (s, 3H), 3.34−
3.22 (q, J = 6.6, 6.2 Hz, 2H), 2.85−2.68 (t, J = 7.2 Hz, 2H), 1.85 (s,
N-(4-(Benzyloxy)-2-(pyridin-3-yl)phenethyl)acetamide (10o). 1H
NMR (400 MHz, CDCl3) δ 8.69−8.52 (dd, J = 18.2, 4.0 Hz, 2H),
7.71−7.63 (dt, J = 7.8, 2.0 Hz, 1H), 7.49−7.31 (m, 7H), 7.06−6.97
(dd, J = 8.5, 2.8 Hz, 1H), 6.84 (d, J = 2.8 Hz, 1H), 5.06 (s, 2H), 3.36−
3.20 (q, J = 6.5 Hz, 2H), 2.78−2.67 (dd, J = 8.1, 6.6 Hz, 2H), 1.90 (s,
3H). 13C NMR (125 MHz, CDCl3) δ 170.1, 157.5, 149.6, 148.5, 139.5,
136.9, 131.2, 129.0, 128.8, 128.3, 127.7, 123.5, 116.9, 115.0, 70.3, 40.7,
32.2, 23.5. HRMS (FAB) m/z: [M + H+] for C22H23N2O2: calcd,
347.1759; found, 347.1754.
N-(4-(Benzyloxy)-2-(pyridin-4-yl)phenethyl)acetamide (10p). 1H
NMR (400 MHz, CDCl3) δ 8.66 (d, J = 5.1 Hz, 2H), 7.46−7.39 (m,
5H), 7.36 (s, 1H), 7.30 (s, 2H), 7.06−7.01 (m, 1H), 6.84 (d, J = 2.7
Hz, 1H), 5.94 (d, J = 4.8 Hz, 1H), 5.09 (s, 2H), 3.35−3.23 (dd, J =
14.5, 6.4 Hz, 2H), 2.74 (t, J = 7.5 Hz, 2H), 1.90 (s, 3H). 13C NMR
(100 MHz, CDCl3) δ 171.4, 158.1, 156.3, 137.2, 132.3, 132.2, 130.8,
128.7, 128.5, 129.7, 127.5, 117.9, 106.2, 103.0, 69.9, 41.1, 29.7, 29.6,
23.1. HRMS (FAB) m/z [M + Na+] for C22H22N2O2Na: calcd,
369.1579; found, 369.1573.
General Hydrogenolysis Procedure for Compounds 10a−p.
N-(2-(5-Hydroxy-[1,1′-biphenyl]-2-yl)ethyl)acetamide (11a). Palladi-
um on carbon (10%, 5 mg) was added to 10a (120 mg, 0.35 mmol) in
degassed MeOH (3.5 mL), and the solution was placed under an
atmosphere of H2. After 12 h, the solution was diluted with CH2Cl2
and filtered through Celite. The eluent was concentrated to afford a
yellow solid, which was purified by column chromatography (SiO2,
100:5, CH2Cl2:MeOH) to afford phenol 11a (64 mg, 0.25 mmol,
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79%) as a pale-yellow amorphous solid. 1H NMR (400 MHz, CDCl3)
δ 7.25−7.14 (m, 5H), 7.11−7.05 (m, 1H), 6.90 (d, J = 8.3 Hz, 1H),
6.64 (d, J = 8.3 Hz, 1H), 6.59 (d, J = 2.5 Hz, 1H), 5.61 (t, J = 5.5 Hz,
1H), 3.12−3.02 (m, 2H), 2.55 (t, J = 7.1 Hz, 2H), 1.66 (s, 3H). 13C
NMR (100 MHz, CDCl3) δ 171.2, 155.2, 143.4, 141.6, 130.8, 129.1,
128.4, 127.2, 127.2, 117.4, 115.0, 41.1, 31.8, 23.2. HRMS m/z [M +
Na+] for C16H17NO2Na: calcd, 278.1151; found, 278.1155.
N-(2-(5-Hydroxy-3′-methoxy-[1,1′-biphenyl]-2-yl)ethyl)-
1
acetamide (11j). H NMR (400 MHz, CDCl3) δ 7.83 (br s, OH),
7.30−7.24 (m, 1H), 7.06 (d, J = 8.2 Hz, 1H), 6.90−6.70 (m, 5H), 5.59
(t, J = 5.7 Hz, 1H), 3.79 (s, 3H), 3.33−3.19 (q, J = 6.9 Hz, 2H), 2.69
(t, J = 7.1 Hz, 2H), 1.85 (s, 3H). 13C NMR (100 MHz, CDCl3) δ
171.1, 159.4, 155.1, 143.3, 143.0, 130.9, 129.5, 127.3, 121.7, 117.2,
115.1, 115.0, 112.6, 55.4, 41.1, 31.8, 23.3. HRMS m/z [M + H+] for
C17H20NO3: calcd, 286.1443; found, 286.1436.
N-(2-(3′-Fluoro-5-hydroxy-[1,1′-biphenyl]-2-yl)ethyl)acetamide
1
(11b). H NMR (500 MHz, MeOD) δ 7.88 (s, 1H), 7.39 (d, J = 7.5
N-(2-(5-Hydroxy-3′-methyl-[1,1′-biphenyl]-2-yl)ethyl)acetamide
(11k). 1H NMR (400 MHz, CDCl3) δ 7.50 (br s, OH), 7.30−7.24 (m,
1H), 7.15 (d, J = 7.6 Hz, 1H), 7.09−7.03 (m, 3H), 6.80 (d, J = 7.6 Hz,
1H), 6.73 (s, 1H), 5.53 (br s, NH), 3.31−3.21 (q, J = 6.7 Hz, 2H),
2.71 (t, J = 7.0 Hz, 2H), 2.37 (s, 3H), 1.85 (s, 3H). 13C NMR (1001
MHz, CDCl3) δ 170.9, 155.0, 143.6, 141.6, 138.1, 130.8, 1230.0, 128.3,
128.0, 127.4, 126.3, 117.4, 114.9, 41.1, 31.8, 23.3, 21.7. HRMS m/z [M
+ Na+] for C17H19NO2Na: calcd, 292.1308; found, 292.1314.
N-(2-(5-Hydroxy-3′-(morpholinomethyl)-[1,1′-biphenyl]-2-yl)-
ethyl)acetamide (11l). 1H NMR (500 MHz, CDCl3) δ 7.36−7.23 (m,
4H), 7.16 (d, J = 7.2 Hz, 1H), 7.07 (d, J = 8.2 Hz, 1H), 6.74−6.69 (dd,
J = 8.2, 2.7 Hz, 1H), 6.62 (d, J = 2.6 Hz, 1H), 5.50 (br s, NH), 3.74
(m, 4H), 3.53 (s, 3H), 3.29−3.20 (q, J = 6.7 Hz, 2H), 2.69 (t, J = 7.0
Hz, 2H), 2.49 (t, J = 4.8 Hz, 4H), 1.87 (s, 3H). 13C NMR (125 MHz,
CDCl3) δ 170.5, 155.0, 143.4, 141.7, 130.9, 130.2, 128.4, 128.2, 117.5,
115.0, 66.9, 63.4, 53.8, 40.8, 32.0, 23.4. HRMS m/z [M + H+] for
C21H27N2O3: calcd, 355.2022; found, 355.2024.
Hz, 1H), 7.16−6.99 (m, 4H), 6.77 (d, J = 8.1 Hz, 1H), 6.62 (d, J = 2.6
Hz, 1H), 3.15 (t, J = 6.6 Hz, 2H), 2.66 (t, J = 7.4 Hz, 2H), 1.80 (s,
3H). 13C NMR (125 MHz, MeOD) δ 173.1, 164.8, 162.9, 156.7,
145.5, 143.3, 132.0, 131.0, 128.3, 126.1, 117.6, 115.9, 114.7, 41.8, 32.8,
22.5. HRMS m/z [M + Na+] for C16H16FNO2Na: calcd, 296.1063;
found, 296.1059.
N-(2-(4′-Fluoro-5-hydroxy-[1,1′-biphenyl]-2-yl)ethyl)acetamide
(11c). 1H NMR (400 MHz, MeOD) δ 7.26−7.20 (m, 2H), 7.11−7.03
(m, 3H), 6.71 (dd, J = 8.3, 2.5 Hz, 1H), 6.56 (d, J = 2.5 Hz, 1H), 3.07
(t, J = 7.6 Hz, 2H), 2.60 (t, J = 7.6 Hz, 2H), 1.78 (s, 3H). 13C NMR
(100 MHz, MeOD) δ 173.0, 156.7, 143.5, 139.2, 131.9, 131.9, 131.8,
128.5, 117.8, 116.0, 115.8, 115.7, 41.8, 32.9, 22.5. HRMS m/z [M +
Na+] for C16H16FNO2Na: calcd, 296.1063; found, 296.1065.
N-(2-(2′-Chloro-5-hydroxy-[1,1′-biphenyl]-2-yl)ethyl)acetamide
(11d). 1H NMR (400 MHz, CDCl3) δ 8.37 (br s, OH), 7.45−7.39 (m,
1H), 7.32−7.24 (m, 2H), 7.21−7.15 (m, 1H), 7.09 (d, J = 8.3 Hz,
1H), 6.85 (dd, J = 8.3, 2.5 Hz, 1H), 6.68 (d, J = 2.6 Hz, 1H), 5.62 (s,
1H), 3.40−3.14 (m, 2H), 2.63−2.44 (dd, J = 7.1, 5.1 Hz, 2H), 1.86 (s,
3H). 13C NMR (125 MHz, CDCl3) δ 171.1, 155.1, 140.5, 140.0, 133.2,
131.4, 130.5, 129.7, 129.0, 127.7, 126.9, 117.3, 115.7, 40.5, 31.8, 23.3.
HRMS m/z [M + H+] for C16H17ClNO2: calcd, 290.0948; found,
290.0941.
N-(2-(3′-Chloro-5-hydroxy-[1,1′-biphenyl]-2-yl)ethyl)acetamide
(11e). 1H NMR (500 MHz, CDCl3) δ 7.40−7.09 (m, 5H), 6.83−6.76
(dq, J = 8.1, 4.9, 3.8 Hz, 1H), 6.76−6.67 (dd, J = 18.3, 2.7 Hz, 1H),
3.34−3.23 (p, J = 6.6 Hz, 2H), 2.77−2.64 (dt, J = 14.3, 7.2 Hz, 2H),
1.76 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 170.8, 154.9, 143.6,
141.6, 131.0, 130.9, 129.7, 129.2, 128.5, 127.5, 117.4, 115.5, 115.0,
41.0, 32.0, 23.4. HRMS m/z [M + Na+] for C16H16ClNO2Na: calcd,
312.0762; found, 312.0788.
N-(2-(5-Hydroxy-3′-(trifluoromethyl)-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (11f). 1H NMR (400 MHz, CDCl3) δ 7.64−7.39 (m, 4H),
7.07 (s, 1H), 6.82 (s, 1H), 6.73 (s, 1H), 6.00 (s, 1H), 3.34−3.18 (q, J
= 6.8 Hz, 2H), 2.66 (t, J = 7.0 Hz, 2H), 1.87 (s, 3H). 13C NMR (100
MHz, CDCl3) δ 171.3, 155.4, 142.4, 141.8, 132.6, 131.0, 130.8, 128.9,
126.9, 125.8, 125.8, 124.0, 117.3, 115.6, 60.7, 41.0, 21.2. HRMS m/z
[M + Na+] for C17H16F3NO2Na: calcd, 346.1031; found, 346.1040.
N-(2-(5-Hydroxy-4′-(trifluoromethyl)-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (11g). 1H NMR (400 MHz, CDCl3) δ 7.54 (d, 2H, J = 8.0
Hz), 7.31 (d, 2H, J = 8.0 Hz), 7.03 (d, 1H, J = 8.3 Hz), 6.72 (dd, 1H, J
= 2.5, 8.3 Hz), 6.59 (d, 1H, J = 2.5 Hz), 4.09 (br s, 2H), 3.10 (t, J = 7.5
Hz, 2H), 2.56 (t, 2H, J = 7.5 Hz), 1.76 (s, 3H). 13C NMR (100 MHz,
CDCl3) δ 170.5, 155.1, 146.3, 141.7, 130.8, 129.5, 127.1, 125.1 (q, J =
4.2 Hz), 116.9, 116.5, 115.3, 45.6, 40.6, 23.0. HRMS m/z [M + H+] for
C17H16F3NO2Na: calcd, 346.1031; found, 346.1025.
N-(2-(4′-((tert-Butyldimethylsilyl)oxy)-5-hydroxy-[1,1′-biphenyl]-
1
2-yl)ethyl)acetamide (11m). H NMR (500 MHz, CDCl3) δ 7.16−
7.10 (d, J = 6.7 Hz, 2H), 7.10−7.06 (d, J = 8.2 Hz, 1H), 7.00 (br s,
OH), 6.91−6.84 (d, J = 8.4 Hz, 2H), 6.79−6.72 (m, 2H), 5.38 (s, 1H),
3.34−3.21 (q, J = 6.6 Hz, 2H), 2.78−2.64 (t, J = 6.9 Hz, 2H), 1.93−
1.81 (s, 3H), 1.00 (s, 9H), 0.24 (s, 6H). 13C NMR (125 MHz, CDCl3)
δ 170.7, 155.0, 154.9, 143.3, 134.6, 130.9, 130.3, 127.8, 120.0, 117.5,
114.7, 41.0, 32.0, 26.0, 23.4, 18.4, −4.1. HRMS (FAB) m/z [M + Na+]
for C22H31NO3SiNa: calcd, 408.1965; found, 408.1960.
N-(2-(Benzo[d][1,3]dioxol-5-yl)-4-hydroxyphenethyl)acetamide
(11n). 1H NMR (500 MHz, CDCl3) δ 8.00 (br s, OH), 7.08−6.98 (d,
J = 8.3 Hz, 1H), 6.81−6.73 (m, 2H), 6.73−6.68 (m, 2H), 6.68−6.64
(dd, J = 7.9, 1.7 Hz, 1H), 5.97−5.92 (s, 2H), 5.70−5.63 (t, J = 5.7 Hz,
1H), 3.29−3.21 (td, J = 7.1, 5.6 Hz, 2H), 2.75−2.63 (t, J = 7.2 Hz,
2H), 1.89−1.81 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 171.1, 155.1,
147.5, 146.8, 143.0, 135.4, 130.8, 127.4, 122.4, 117.5, 114.9, 109.8,
108.3, 101.2, 41.1, 31.9, 23.3. HRMS (FAB) m/z [M + Na+] for
C17H17NO4Na: calcd, 322.1050; found, 322.1022.
N-(4-Hydroxy-2-(pyridin-3-yl)phenethyl)acetamide (11o). 1H
NMR (400 MHz, CDCl3) δ 8.54 (s, 2H), 7.72 (d, J = 7.9 Hz, 1H),
7.42−7.34 (dd, J = 8.0, 4.8 Hz, 1H), 7.14 (d, J = 8.4 Hz, 1H), 6.90−
6.84 (dd, J = 8.3, 2.7 Hz, 1H), 6.73 (d, J = 2.7 Hz, 1H), 5.82 (t, J = 5.9
Hz, 2H), 3.33−3.19 (q, J = 6.8 Hz, 2H), 2.69 (t, J = 7.2 Hz, 2H), 1.85
(s, 3H). 13C NMR (100 MHz, CDCl3) δ 170.7, 156.1, 149.1, 147.7,
138.8, 138.0, 131.4, 127.3, 123.7, 117.5, 116.4, 100.2, 40.9, 32.0, 23.4.
HRMS (FAB) m/z [M + H+] for C15H17N2O2: calcd, 257.1290; found,
257.1297.
N-(4-Hydroxy-2-(pyridin-4-yl)phenethyl)acetamide (11p). 1H
NMR (400 MHz, CDCl3) δ 8.69−8.60 (m, 2H), 7.25 (d, J = 1.5
Hz, 2H), 7.17 (d, J = 8.4 Hz, 1H), 6.90−6.83 (dd, J = 8.4, 2.7 Hz, 1H),
6.70 (d, J = 2.7 Hz, 1H), 6.02 (br s, OH), 5.47 (s, 1H), 3.33−3.24 (q, J
= 7.0 Hz, 2H), 2.71 (t, J = 7.4 Hz, 2H), 1.90 (s, 3H). 13C NMR (125
MHz, CDCl3) δ 173.0, 157.1, 152.8, 149.7, 149.6, 141.3, 132.4, 128.0,
126.2, 117.2, 117.1, 116.9, 41.8, 32.8, 22.5. HRMS (FAB) m/z [M +
Na+] for C15H16N2O2Na: calcd, 279.1104; found, 279.1109.
General Procedure for Activated Noviose Carbamate
Coupling and Followed by Methanolysis of Compounds
11a−p. Borontrifluoride etherate (6.2 μL, 0.05 mmol) was added to
11a (0.25 mmol) and activated noviose (0.2 mmol) in 2.5 mL
anhydrous CH2Cl2. After stirring at room temperature for 2 h,
triethylamine (150 μL) was added and concentrated. The residue was
partially purified via column chromatography (SiO2, 100:8
CH2Cl2:acetone) to give noviose coupled product as a colorless
foam, which was used directly for next step.
N-(2-(5-Hydroxy-2′-(methylthio)-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (11h). 1H NMR (500 MHz, CDCl3) δ 7.40−7.34 (m, 1H),
7.25−7.14 (m, 3H), 7.12−7.07 (m, 1H), 6.86−6.82 (dd, J = 8.4, 2.7
Hz, 1H), 6.68 (d, J = 2.7 Hz, 1H), 5.51 (br s, NH), 3.42−3.16 (m,
2H), 2.55 (t, J = 6.8 Hz, 2H), 2.37 (s, 3H), 1.85 (s, 3H). 13C NMR
(125 MHz, CDCl3) δ 170.5, 154.5, 141.2, 139.1, 137.6, 130.7, 123.0,
128.8, 128.5, 124.6, 124.0, 117.3, 115.6, 40.2, 31.6, 23.4, 15.2. HRMS
m/z [M + Na+] for C17H19NO2SNa: calcd, 324.1034; found, 324.1035.
N-(2-(5-Hydroxy-2′-methoxy-[1,1′-biphenyl]-2-yl)ethyl)-
1
acetamide (11i). H NMR (400 MHz, CDCl3) δ 7.52 (br s, OH),
7.41−7.31 (m, 1H), 7.14−7.07 (dd, J = 8.4, 6.4 Hz, 1H), 7.05−6.94
(m, 3H), 6.83−6.76 (dd, J = 8.3, 2.7 Hz, 1H), 6.70 (d, J = 2.7 Hz, 1H),
5.55 (s, 1H), 3.76 (s, 3H), 3.41−3.17 (ddt, J = 34.4, 13.1, 6.5 Hz, 2H),
2.57 (t, J = 6.9 Hz, 2H), 1.85 (s, 3H). 13C NMR (125 MHz, CDCl3) δ
171.0, 156.4, 155.1, 139.9, 131.3, 130.5, 130.1, 129.1, 128.5, 121.0,
117.7, 115.2, 111.4, 55.9, 40.7, 31.7, 23.3. HRMS m/z [M + Na+] for
C17H19NO3Na: calcd, 308.1263; found, 308.1264.
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Triethylamine (0.22 mL, 10%) was added to the cyclic carbonate
(100 mg, 0.22 mmol) in MeOH (2.2 mL). After 12 h, the solvent was
concentrated and the residue was purified via column chromatography
(SiO2, 10:1, CH2Cl2:acetone) to afford inseparable diastereomers 13a
(see following experimental section for diastereoselectivities) as a
colorless amorphous solids. Compounds 13b−m were synthesized
using this procedure.
1H), 3.60 (s, 3H), 3.34 (dd, 1H, J = 1.9, 9.1 Hz), 3.28 (m, 2H), 2.75
(dt, 4H, J = 7.3, 14.5 Hz), 1.88 (s, 3H), 1.37 (s, 3H), 1.22 (s, 3H). 13
C
NMR (125 MHz, CDCl3) δ 170.1, 155.4, 143.5, 142.0, 134.3, 131.0,
130.9, 129.8, 129.4, 128.5, 127.6, 127.4, 118.2, 115.7, 97.9, 84.6, 78.4,
71.5, 68.7, 62.1, 40.8, 32.1, 29.2, 23.6, 23.1. HRMS m/z [M + Na+] for
C24H30ClNO6Na: calcd, 486.1659; found, 486.1642.
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-3′-(trifluoromethyl)-[1,1′-biphenyl]-2-yl)-
ethyl)acetamide (13f). Colorless amorphous solid (52% yield over 2
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-[1,1′-biphenyl]-2-yl)ethyl)acetamide
1
1
steps). H NMR (500 MHz, CDCl3) δ 7.64 (d, 1H, J = 7.7 Hz), 7.55
(13a). Colorless amorphous solid (63% yield over 2 steps). H NMR
(t, 2H, J = 7.6 Hz), 7.49 (m, 1H), 7.23 (d, 1H, J = 8.5 Hz), 7.06 (dd,
1H, J = 2.7, 8.4 Hz), 6.89 (d, 1H, J = 2.7 Hz), 5.56 (d, 1H, J = 2.2 Hz),
5.31 (s, 1H), 4.19 (m, 2H), 3.60 (s, 3H), 3.34 (d, 1H, J = 9.1 Hz), 3.29
(dd, 2H, J = 7.0, 13.3 Hz), 2.72 (t, 2H, J = 7.3 Hz), 2.69 (s, 1H), 2.64
(s, 1H), 1.87 (s, 3H), 1.37 (s, 3H), 1.22 (s, 3H). 13C NMR (125 MHz,
CDCl3) δ 170.1, 155.4, 142.1, 141.9, 132.6, 131.0, 130.7 (q, J = 31.5
Hz), 129.4, 129.0, 125.9 (q, J = 3.6, 7.2 Hz), 125.3, 124.2 (q, J = 3.6,
7.2 Hz), 123.1, 118.0, 115.8, 97.9, 84.4, 77.4, 71.4, 68.7, 62.0, 40.6,
32.1, 29.8, 29.2, 23.4, 23.0. HRMS m/z [M + Na+] for
C25H30F3NO6Na: 520.1923; found, 520.1932. This material was
determined to be 97.2% pure (retention time = 7.631) by HPLC
(Phenomenex Luna C-18, 5 μm, 10 mm × 250 mm column eluting
with 30% CH3CN, 70% H2O, flow rate 5.0 mL/min).
(500 MHz, CDCl3) δ 7.41−7.28 (m, 3H), 7.28−7.18 (dt, J = 5.9, 3.2
Hz, 2H), 7.13 (m, 1H), 6.97 (m, 1H), 6.92−6.78 (dd, J = 7.6, 2.7 Hz,
1H), 5.55−5.47 (dd, J = 7.7, 2.7 Hz, 1H), 5.39 (m, 1H), 4.14 (m, 2H),
3.58−3.46 (m, 3H), 3.34−3.15 (m, 4H), 3.03 (d, J = 5.5 Hz, 1H),
2.77−2.65 (m, 2H), 1.84−1.76 (m, 3H), 1.31 (d, J = 4.9 Hz, 3H),
1.21−1.10 (m, 3H). 13C NMR (125 MHz, CDCl3) δ 170.3, 155.4,
143.5, 141.4, 130.8, 129.5, 129.2, 128.5, 127.4, 118.2, 115.2, 98.1, 84.5,
78.4, 71.5, 68.8, 62.0, 40.8, 32.1, 29.2, 23.4, 23.1. HRMS m/z [M +
H+] for C24H32NO6: calcd, 430.2224; found, 430.2227.
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-3′-fluoro-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13b). Colorless amorphous solid (51% yield over 2 steps).
1H NMR (500 MHz, CDCl3) δ 7.39 (dd, 1H, J = 7.9, 13.9 Hz), 7.22
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-4′-(trifluoromethyl)-[1,1′-biphenyl]-2-yl)-
ethyl)acetamide (13g). Colorless amorphous solid (49% yield over 2
(d, 1H, J = 8.5 Hz), 7.07 (dd, 2H, J = 7.5, 10.5 Hz), 7.02 (dd, 1H, J =
2.8, 8.4 Hz), 6.99 (m, 1H), 6.91 (d, 1H, J = 2.7 Hz), 5.34 (d, 1H, J =
1.3 Hz), 5.28 (s, 1H), 4.20 (d, 1H, J = 2.2 Hz), 3.80 (m, 1H), 3.63 (s,
3H), 3.30 (d, 1H), 3.28 (m, 2H), 2.75 (t, 2H, J = 7.2 Hz), 2.63 (m,
2H, J = 15.9 Hz), 1.87 (s, 3H), 1.41 (s, 3H), 1.28 (s, 3H). 13C NMR
(125 MHz, CDCl3) δ 169.9, 163.5−161.6 (d, J = 251 Hz) 155.0, 143.2
(d, J = 7.8 Hz), 142.1 (d, J = 1.8 Hz), 130.9, 130.1, 130.0 (d, J = 8.8
Hz), 124.8 (d, J = 2.8 Hz), 118.0, 116.0 (d, J = 8.8 Hz), 115.4, 114.3
(d, J = 21.6 Hz), 93.8, 84.2, 76.0, 71.3, 71.1, 62.0, 40.4, 32.0, 28.6, 23.3,
18.5. HRMS m/z: [M + H+] for C24H31FNO6: calcd, 448.2180; found,
448.2174. This material was determined to be 95.6% pure (retention
time = 6.401) by HPLC (Phenomenex Luna C-18, 5 μm, 10 mm ×
250 mm column eluting with 30% CH3CN, 70% H2O, flow rate 5.0
mL/min).
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-4′-fluoro-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13c). Colorless amorphous solid (57% yield over 2 steps).
1H NMR (500 MHz, CDCl3) δ 7.25 (dd, 2H, J = 5.4, 8.6 Hz), 7.18 (d,
1H, J = 8.5 Hz), 7.10 (t, 2H, J = 8.7 Hz), 7.01 (dd, 1H, J = 2.7, 8.5
Hz), 6.87 (d, 1H, J = 2.7 Hz), 5.54 (d, 1H, J = 2.2 Hz), 5.37 (t, 1H, J =
5.2 Hz), 4.20 (dd, 1H, J = 3.3, 9.1 Hz), 4.15 (m, 1H), 3.59 (s, 3H),
3.33 (d, 1H, J = 9.1 Hz), 3.26 (q, 2H, J = 6.9 Hz), 2.97 (s, 1H), 2.81
(s, 1H), 2.72 (t, 2H, J = 7.3), 1.87 (s, 3H), 1.36 (s, 3H), 1.22 (s, 3H).
13C NMR (125 MHz, CDCl3) δ 170.2, 163.2−161.3 (d, J = 250 Hz),
155.3, 142.3, 137.2 (d, J = 3.2 Hz), 130.8, 130.8, 130.7, 129.5, 118.1,
115.4, 115.3, 115.3, 97.9, 84.4, 78.3, 71.4, 68.7, 62.0, 40.6, 32.1, 29.1,
23.4, 23.1. HRMS m/z [M + Na+] for C24H30FNO6: calcd, 470.1955;
found, 470.1958.
N-(2-(2′-Chloro-5-(((3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-di-
methyltetrahydro-2H-pyran-2-yl)oxy)-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13d). Colorless amorphous solid (62% yield over 2 steps).
1H NMR (500 MHz, CDCl3) δ 7.46 (m, 1H), 7.31 (m, 2H), 7.21 (m,
2H), 7.03 (m, 1H), 6.86 (dd, 1H, J = 2.7, 13.2 Hz), 5.55 (m, 1H), 5.42
(s, 1H), 4.20 (dt, 1H, J = 3.0, 9.1 Hz), 4.14 (m, 1H), 3.59 (s, 3H), 3.33
(dd, 1H, J = 2.5, 9.1 Hz), 3.26 (ddt, 2H, J = 4.8, 6.8, 9.3 Hz), 3.11 (s,
1H), 2.93 (s, 1H), 2.58 (tq, 2H, J = 7.1, 14.2 Hz), 1.86 (s, 3H), 1.35
(d, 3H, J = 2.4 Hz), 1.20 (t, 3H, J = 5.8 Hz). 13C NMR (125 MHz,
CDCl3) δ 170.2, 155.2, 140.6, 140.5, 139.8, 133.4, 131.4, 130.5, 129.8,
126.9, 118.1, 117.9, 116.05, 97.9, 84.5, 78.4, 71.5, 71.4, 68.7, 62.1, 62.0,
40.2, 40.2, 32.1, 32.1, 29.3, 29.2, 23.5, 23.1, 23.0. HRMS m/z [M +
Na+] for C24H30ClNO6Na: 486.1659; found, 486.1652.
N-(2-(3′-Chloro-5-(((3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-di-
methyltetrahydro-2H-pyran-2-yl)oxy)-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13e). Colorless amorphous solid (55% yield over 2 steps).
1H NMR (500 MHz, CDCl3) δ 7.35 (m, 2H), 7.28 (m, 1H), 7.18 (m,
1
steps). H NMR (400 MHz, CDCl3) δ 7.70 (d, J = 7.6 Hz, 2H), 7.43
(d, J = 7.9 Hz, 2H), 7.24 (d, J = 8.4 Hz, 1H), 7.09−7.03 (dd, J = 8.6,
2.7 Hz, 1H), 6.90 (d, J = 2.7 Hz, 1H), 5.55 (d, J = 2.3 Hz, 1H), 5.33
(m, 1H), 4.26−4.11 (m, 2H), 3.60 (s, 3H), 3.36−3.25 (m, 3H), 2.74
(t, J = 7.4 Hz, 2H), 2.56 (br s, 2OH), 1.88 (s, 3H), 1.37 (s, 3H), 1.22
(s, 3H). 13C NMR (125 MHz, MeOD) δ 173.1, 156.8, 146.9, 143.2,
132.1, 130.9, 130.7, 130.5, 130.2, 126.3, 126.2, 124.7, 118.5, 116.8,
100.1, 85.3, 79.5, 72.8, 69.5, 62.1, 41.7, 32.9, 29.2, 23.6, 22.5. HRMS
m/z [M + Na+] for C25H30F3NO6Na: 520.1923; found, 520.1934.
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-2′-(methylthio)-[1,1′-biphenyl]-2-yl)-
ethyl)acetamide (13h). Colorless amorphous solid (63% yield over 2
1
steps). H NMR (400 MHz, CDCl3) δ 7.36 (t, 1H, J = 7.0 Hz), 7.27
(m, 3H), 7.09 (m, 1H), 7.01 (m, 1H), 6.87 (s, 1H), 5.64 (s, 1H), 5.54
(m, 1H), 4.16 (m, 2H), 3.32 (d, 2H, J = 8.8 Hz), 3.27 (m, 2H), 3.06
(s, 1H), 2.56 (t, 2H, J = 6.2 Hz), 2.36 (d, 3H, J = 7.6 Hz), 1.83 (s,
3H), 1.33 (s, 3H), 1.20 (s, 3H). 13C NMR (100 MHz, CDCl3) δ
170.3, 155.1, 155.0, 141.0, 138.9, 130.5, 130.1, 129.8, 128.4, 124.6,
124.2, 118.3, 116.2, 115.9, 97.9, 84.5, 78.3, 71.5, 68.7, 62.0, 53.6, 40.1,
31.7, 29.3, 23.3, 15.3, 15.2. HRMS m/z [M + Na+] for
C25H33NO6SNa: calcd, 498.1926; found, 498.1925. This material
was determined to be 95% pure (retention time = 7.465) by HPLC
(Phenomenex Luna C-18, 5 μm, 10 mm × 250 mm column eluting
with 30% CH3CN, 70% H2O, flow rate 5.0 mL/min).
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-2′-methoxy-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13i). Colorless amorphous solid (41% yield over 2 steps).
1H NMR (500 MHz, CDCl3) δ 7.36 (ddd, 1H, J = 1.8, 7.6, 8.2 Hz),
7.18 (d, 1H, J = 8.3 Hz), 7.12 (t, 1H, J = 5.8 Hz), 7.02 (m, 3H), 6.87
(dd, 1H, J = 2.3, 11.3 Hz), 5.54 (s, 1H), 5.39 (s, 1H), 4.21 (dt, 1H, J =
3.3, 9.0 Hz), 4.15 (m, 1H), 3.77 (d, 3H, J = 6.9 Hz), 3.60 (s, 3H), 3.33
(d, 1H, J = 8.7 Hz), 3.29 (m, 2H), 2.73 (s, 1H), 2.66 (s, 1H), 2.60 (dd,
2H, J = 6.5, 12.8 Hz), 1.84 (s, 3H), 1.37 (s, 3H), 1.24 (s, 3H). 13C
NMR (125 MHz, CDCl3) δ 170.0, 156.4, 155.2, 139.9, 131.2, 130.8,
130.2, 130.0, 129.2, 120.9, 118.6, 118.3, 115.7, 115.2, 111.4, 111.2,
98.0, 97.9, 84.5, 78.2, 71.4, 68.7, 62.0, 55.9, 55.9, 40.3, 31.9, 30.2, 29.3,
29.2, 23.4, 23.1. HRMS m/z [M + H+] for C25H34NO7: calcd,
460.2335; found, 460.2336. This material was determined to be 96.1%
pure (retention time = 5.057) by HPLC (Phenomenex Luna C-18, 5
μm, 10 mm × 250 mm column eluting with 30% CH3CN, 70% H2O,
flow rate 5.0 mL/min).
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-3′-methoxy-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13j). Colorless amorphous solid (53% yield over 2 steps).
1H NMR (400 MHz, CDCl3) δ 7.31 (t, J = 7.9 Hz, 1H), 7.17 (d, J =
2H), 7.03 (dd, 1H, J = 2.7, 8.5 Hz), 6.87 (d, 1H, J = 2.7 Hz), 5.55 (t,
1H, J = 2.5 Hz), 5.34 (m, 1H), 4.21 (dd, 1H, J = 3.1, 9.1 Hz), 4.16 (m,
5808
dx.doi.org/10.1021/jm300544c | J. Med. Chem. 2012, 55, 5797−5812

Journal of Medicinal Chemistry
Article
8.5 Hz, 1H), 7.02−6.96 (dd, J = 8.5, 2.7 Hz, 1H), 6.92−6.83 (m, 4H),
6.81 (d, J = 1.5 Hz, 2H), 5.54 (d, J = 2.2 Hz, 1H), 5.45 (s, 1H), 4.25−
4.16 (dd, J = 9.1, 3.2 Hz, 1H), 4.17−4.10 (dd, J = 3.3, 2.2 Hz, 1H),
3.82 (s, 3H), 3.58 (s, 3H), 3.39−3.20 (m, 3H), 3.24 (br s, OH), 2.97
(br s, OH), 2.75 (t, J = 7.1 Hz, 2H), 1.85 (s, 3H), 1.35 (s, 3H), 1.20 (s,
3H). 13C NMR (125 MHz, CDCl3) δ 170.4, 159.5, 155.3, 143.3, 142.8,
130.8, 129.5, 129.5, 121.7, 118.0, 115.3, 115.1, 112.7, 98.1, 84.5, 78.4,
71.5, 68.7, 62.0, 55.4, 40.9, 32.0, 29.1, 23.4, 23.1. HRMS m/z [M +
H+] for C25H34NO7: calcd, 460.2335; found, 460.2322.
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-3′-methyl-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13k). Colorless amorphous solid (44% yield over 2 steps).
1H NMR (400 MHz, CDCl3) δ 7.32−7.27 (m, 1H), 7.16 (d, J = 6.6
Hz, 2H), 7.10−7.04 (m, 2H), 6.99 (d, J = 8.5 Hz, 1H), 6.88 (s, 1H),
5.55 (s, 1H), 5.41 (s, 1H), 4.25−4.08 (m, 2H), 3.57 (s, 3H), 3.37−
3.20 (m, 5H), 2.75 (t, J = 7.0 Hz, 2H), 2.39 (s, 3H), 1.83 (s, 3H), 1.35
(s, 3H), 1.20 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 170.4, 155.3,
143.6, 141.3, 138.1, 130.8, 130.0, 129.5, 128.3, 128.1, 126.3, 118.1,
115.1, 98.1, 84.5, 78.4, 71.5, 68.7, 62.0, 40.9, 32.0, 29.2, 23.4, 23.1,
21.7. HRMS m/z [M + H+] for C25H33NO6Na: calcd, 466.2206;
found, 466.2203.
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-3′-(morpholinomethyl)-[1,1′-biphenyl]-2-
yl)ethyl)acetamide (13l). Colorless amorphous solid (47% yield over
2 steps). 1H NMR (500 MHz, CDCl3) δ 7.41−7.29 (m, 2H), 7.27 (m,
1H), 7.19 (d, J = 8.1 Hz, 2H), 7.04−6.99 (dd, J = 8.5, 2.7 Hz, 1H),
6.91 (d, J = 2.7 Hz, 1H), 5.55 (d, J = 2.4 Hz, 1H), 5.35 (s, 1H), 4.26−
4.18 (dd, J = 9.0, 3.3 Hz, 1H), 4.15 (t, J = 2.8 Hz, 1H), 3.72 (t, J = 4.7
Hz, 4H), 3.59 (s, 3H), 3.56 (s, 2H), 3.34 (d, J = 9.0 Hz, 1H), 3.30−
3.21 (q, J = 6.7 Hz, 2H), 2.75 (t, J = 7.1 Hz, 2H), 2.58−2.41 (m, 6H),
1.85 (s, 3H), 1.36 (s, 3H), 1.23 (s, 3H). 13C NMR (125 MHz, CDCl3)
δ 155.4, 143.4, 141.5, 137.8, 130.9, 130.1, 129.6, 128.5, 128.3, 128.2,
118.2, 115.3, 98.1, 84.6, 78.4, 71.5, 68.8, 67.1, 63.5, 62.0, 53.8, 40.7,
32.2, 29.2, 23.5, 23.2. HRMS (FAB) m/z [M + Na+] for
C29H40N2O7Na: calcd, 551.2728; found, 551.2734.
determined to be 98.4% pure (retention time = 4.384) by HPLC
(Phenomenex Luna C-18, 5 μm, 10 mm × 250 mm column eluting
with 40% CH3CN, 60% H2O, flow rate 5.0 mL/min).
N-(4-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetrahy-
dro-2H-pyran-2-yl)oxy)-2-(pyridin-3-yl)phenethyl)acetamide (13o).
1
Colorless amorphous solid (37% yield over 2 steps). H NMR (500
MHz, CDCl3) δ 8.55 (d, J = 3.9 Hz, 1H), 8.49 (s, 1H), 7.60 (m, 1H),
7.35 (dd, J = 7.8, 4.5 Hz, 1H), 7.20 (d, J = 8.5 Hz, 1H), 7.05−6.99 (dd,
J = 8.4, 2.7 Hz, 1H), 6.85 (d, J = 2.6 Hz, 1H), 5.52 (d, J = 2.4 Hz, 1H),
5.36 (s, 1H), 4.14 (dd, J = 3.4, 9.1 Hz, 1H), 4.10 (t, J = 2.7 Hz, 1H),
3.59 (s, 3H), 3.31 (d, J = 9.0 Hz, 1H), 3.27−3.20 (m, 2H), 2.68 (t, J =
7.3 Hz, 2H), 1.86 (s, 3H), 1.33 (s, 3H), 1.17 (s, 3H). 13C NMR (125
MHz, CDCl3) δ 170.2, 155.5, 149.8, 148.7, 139.5, 136.8, 131.1, 131.0,
130.6, 129.8, 123.4, 118.3, 118.2, 116.1, 98.0, 84.5, 78.5, 71.4, 68.7,
62.1, 40.7, 32.2, 29.2, 23.5, 23.1. HRMS (FAB) m/z [M + Na+] for
C23H31N2O6: calcd, 431.2182; found, 431.2194.
N-(4-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetrahy-
dro-2H-pyran-2-yl)oxy)-2-(pyridin-4-yl)phenethyl)acetamide (13p).
1
Colorless amorphous solid (42% yield over 2 steps). H NMR (400
MHz, CDCl3) δ 8.73−8.63 (dd, J = 5.7, 3.9 Hz, 2H), 7.27−7.23 (m,
3H), 7.11−7.03 (m, 1H), 6.86 (t, J = 2.8 Hz, 1H), 5.55 (d, J = 2.3 Hz,
1H), 5.41−5.31 (m, 2H), 4.26−4.13 (m, 2H), 4.05 (d, J = 6.9 Hz,
1H), 3.61 (s, 3H), 3.36−3.25 (m, 2H), 2.78−2.71 (dd, J = 8.3, 6.8 Hz,
2H), 1.90 (s, 3H), 1.39 (s, 3H), 1.24 (s, 3H). 13C NMR (125 MHz,
CDCl3) δ 170.1, 155.5, 149.8, 140.5, 131.4, 129.1, 124.4, 117.9, 116.3,
98.0, 94.1, 84.5, 71.5, 71.4, 68.7, 62.1, 40.7, 32.2, 29.2, 28.8, 23.5, 23.1,
18.7. HRMS (FAB) m/z [M + Na+] for C23H30N2O6Na: calcd,
453.2001; found, 453.1972.
(Z)-4-(Benzyloxy)-2-(methoxymethoxy)-1-(2-nitrovinyl)benzene
(15). Nitromethane (11.5 mL) was added to a mixture of aldehyde 14
(1.24 g, 4.6 mmol) and ammonium acetate (0.63 g, 8.2 mmol) and
heated to 50 °C. Upon completion (∼20 min), the reaction mixture
was cooled to room temperature and purified without workup by
column chromatography (SiO2, 4:1, Hex:EtOAc) to afford nitro-
1
styrene 15 as a colorless oil (1.22 g, 84%). H NMR (400 MHz,
CDCl3) δ 8.17 (d, J = 13.4 Hz, 1H), 7.80 (d, J = 13.6 Hz, 1H), 7.50−
7.32 (m, 6H), 6.88 (d, J = 2.5 Hz, 1H), 6.67 (m, 1H), 5.30 (s, 2H),
5.12 (s, 2H), 3.52 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 163.4,
159.0, 136.1, 136.0, 135.6, 133.5, 128.8, 128.5, 127.7, 127.7, 113.0,
108.6, 102.2, 94.7, 70.5, 56.6. HRMS (FAB) m/z [M + Na+] for
C17H17NO5Na: calcd, 338.1004; found, 338.1007.
N-(2-(5-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetra-
hydro-2H-pyran-2-yl)oxy)-4′-hydroxy-[1,1′-biphenyl]-2-yl)ethyl)-
acetamide (13m). After cyclic carbonate hydrolysis following the
same procedure as compound 13a, the crude TBS protected
compound was dissolved in THF (2 mL) and tertrabutylammonium
fluoride (1.5 equiv) was added dropwise at 0 °C under argon
atmosphere. After 1 h, the reaction was quenched with water and
extracted with EtOAc (3 × 10 mL); combined organic fractions were
washed with saturated aqueous sodium chloride, dried over anhydrous
Na2SO4, filtered, and concentrated. The residue was purified by
column chromatography (SiO2; 10:1, CH2Cl2:acetone) to afford
4′-(Benzyloxy)-2′-(methoxymethoxy)-2-nitro-1,2,3,6-tetrahydro-
1,1′-biphenyl (16). Nitrostyrene 15 (0.65 g, 2.06 mmol) was dissolved
in toluene (0.6 mL) in a 2 mL sealed tube and cooled to −78 °C.
Butadiene was bubbled into the solution to double the volume, and
then the tube was sealed and heated to reflux for 48 h. To prevent
bumping of the butadiene gas, the tube was cooled again to −78 °C
and used directly in purification by column chromatography (SiO2;
1
acetamide 13m as a amorphous solid (40% yield over 3 steps). H
NMR (500 MHz, MeOD) δ 7.20 (d, J = 8.4 Hz, 1H), 7.15−7.08 (d, J
= 8.4 Hz, 2H), 6.96 (dd, J = 8.4, 2.6 Hz, 1H), 6.85−6.79 (m, 3H), 5.45
(d, J = 2.4 Hz, 1H), 4.12 (dd, J = 9.3, 3.3 Hz, 1H), 3.96 (t, J = 2.8 Hz,
1H), 3.59 (s, 3H), 3.21 (d, J = 9.3, Hz, 1H), 3.16 (dd, J = 8.5, 6.5 Hz,
2H), 2.70 (dd, J = 8.5, 6.5 Hz, 2H), 1.84 (s, 3H), 1.32 (s, 3H), 1.18 (s,
3H). 13C NMR (125 MHz, MeOD) δ 173.1, 157.7, 156.6, 144.7,
134.0, 131.7, 131.2, 131.1, 118.9, 116.0, 115.7, 100.1, 85.4, 79.4, 72.8,
69.5, 62.1, 41.8, 33.0, 29.2, 23.6, 22.5. HRMS (FAB) m/z [M + Na+]
for C24H31NO7Na: calcd, 468.1998; found, 468.1999.
N-(2-(Benzo[d][1,3]dioxol-5-yl)-4-(((3R,4S,5R)-3,4-dihydroxy-5-
methoxy-6,6-dimethyltetrahydro-2H-pyran-2-yl)oxy)phenethyl)-
acetamide (13n). Colorless amorphous solid (51% yield over 2 steps).
1H NMR (500 MHz, CDCl3) δ 7.15 (d, J = 8.5 Hz, 1H), 7.00−6.96
(dd, J = 8.5, 2.7 Hz, 1H), 6.88 (d, J = 2.6 Hz, 1H), 6.84 (d, J = 7.9 Hz,
1H), 6.76 (d, J = 1.6 Hz, 1H), 6.74−6.69 (m, 1H), 6.01 (s, 2H), 5.54
(d, J = 2.4 Hz, 1H), 5.40 (s, 1H), 4.21 (dd, J = 9.1, 3.3 Hz, 1H), 4.14
(t, J = 2.7 Hz, 2H), 3.58 (s, 3H), 3.33 (d, J = 9.1 Hz, 1H), 3.30−3.23
(q, J = 6.9 Hz, 2H), 3.11 (br s, OH), 2.92 (br s, OH), 2.74 (t, J = 7.2
Hz, 2H), 1.86 (s, 3H), 1.34 (s, 3H), 1.20 (s, 3H). 13C NMR (125
MHz, CDCl3) δ 170.2, 155.4, 147.7, 147.0, 143.1, 135.3, 130.8, 129.7,
122.6, 118.3, 115.2, 109.9, 108.4, 101.3, 98.1, 84.6, 78.4, 71.5, 68.8,
62.0, 40.8, 32.1, 29.2, 23.4, 23.2. HRMS (FAB) m/z [M + Na+] for
C25H31NO8Na: calcd, 496.1947; found, 496.1940. This material was
1
3:1, Hex:EtOAc) to afford cyclohexene adduct 16 (0.72 g, 95%). H
NMR (500 MHz, CDCl3) δ 7.40 (m, 4H), 7.36−7.28 (m, 1H), 7.06
(d, J = 8.4 Hz, 1H), 6.80 (d, J = 2.4 Hz, 1H), 6.56 (dd, J = 8.4, 2.5 Hz,
1H), 5.86−5.77 (m, 1H), 5.71 (ddd, J = 9.8, 5.1, 2.3 Hz, 1H), 5.27−
5.20 (m, 1H), 5.20 (s, 2H), 5.00 (s, 2H), 3.70 (dt, J = 17.0, 8.7 Hz,
1H), 3.49 (s, J = 12.7 Hz, 3H), 2.84−2.74 (m, 1H), 2.71 (ddd, J =
13.2, 8.4, 1.5 Hz, 1H), 2.45 (m, 2H). 13C NMR (125 MHz, CDCl3) δ
159.2, 156.1, 136.9, 129.3, 128.6, 127.0, 122.5, 120.9, 107.8, 120.6,
94.6, 85.6, 70.1, 31.5, 31.3, 29.7.
N-(4′-(Benzyloxy)-2′-(methoxymethoxy)-1,2,3,6-tetrahydro-[1,1′-
biphenyl]-2-yl)acetamide (17). Nitro compound 16 (0.23 g, 0.62
mmol) was dissolved in isopropyl alcohol (12.4 mL) and aqueous 1 M
HCl (6.2 mL). Zinc dust (811 mg, 12.4 mmol) was added sequentially,
and the mixture was stirred vigorously at 50 °C for 1.5 h. After cooling
to room temperature, saturated NaHCO3 (8 mL) was added and the
resulting mixture was stirred for an additional 20 min. The solids were
removed by filtration, and the remaining solution was extracted with
CH2Cl2 (3 × 20 mL). The organic layers were combined and washed
with aqueous saturated sodium chloride solution, dried over Na2SO4,
filtered, and concentrated to afford amine as a colorless oil (0.20 g,
0.59 mmol, 95%), which was used for next reaction without further
purification.
5809
dx.doi.org/10.1021/jm300544c | J. Med. Chem. 2012, 55, 5797−5812

Journal of Medicinal Chemistry
Article
Acetic anhydride (62 μL, 0.65 mmol) and triethylamine (95 μL,
0.68 mmol) were added to a solution of the amine (0.62 mmol) in
CH2Cl2 (6.2 mL) at room temperature. After 3 h, the reaction was
quenched with saturated aqueous ammonium chloride and extracted
with CH2Cl2 (3 × 10 mL); combined organic fractions were washed
with saturated aqueous NaCl, dried over anhydrous Na2SO4, filtered,
and concentrated. The residue was purified by column chromatog-
raphy (SiO2; 3:1, Hex:EtOAc) to afford acetamide 17 (0.17 g, 74%).
1H NMR (500 MHz, CDCl3) δ 7.42 (d, J = 7.8 Hz, 2H), 7.39−7.33 (t,
J = 7.2 Hz, 2H), 7.33−7.28 (m, 1H), 7.12 (d, J = 8.5 Hz, 1H), 6.77 (s,
1H), 6.63 (d, J = 8.5 Hz, 1H), 5.90 (d, J = 8.4 Hz, 1H), 5.71 (d, J =
36.2 Hz, 2H), 5.17 (s, 2H), 5.02 (s, 2H), 4.36−4.23 (dtd, J = 13.8,
10.4, 9.9, 7.2 Hz, 1H), 3.50 (s, 3H), 3.31−3.22 (dd, J = 18.6, 7.9 Hz,
1H), 2.59 (d, J = 17.3 Hz, 1H), 2.33 (s, 2H), 2.02−1.93 (m, 1H), 1.74
(s, 3H). 13C NMR (125 MHz, CDCl3) δ 169.8, 158.3, 156.1, 136.9,
128.5, 128.3, 127.9, 127.6, 126.7, 125.0, 124.4, 108.0, 102.9, 95.6, 70.0,
56.2, 48.8, 37.4, 33.0, 32.6, 23.1. HRMS (FAB) m/z [M + Na+] for
C23H27NO4Na: calcd, 404.1832; found, 404.1827.
MHz, CDCl3) δ 169.7, 156.9, 142.4, 141.9, 136.9, 132.6, 131.1, 130.8,
129.1, 128.7, 128.6, 128.2, 127.7, 126.6, 126.0, 125.9, 125.0, 124.3,
124.2, 116.3, 115.3, 70.2, 49.4, 40.6, 35.2, 33.1, 23.4. HRMS (FAB) m/
z [M + Na+] for C28H26F3NO2Na: calcd, 488.1813; found, 488.1812.
N-(3″-Fluoro-4′-hydroxy-1,2,3,6-tetrahydro-[1,1′:2′,1″-terphen-
yl]-2-yl)acetamide (21a). 1,2-Ethanedithiol (0.22 mL, 2.66 mmol)
and BF3.OEt2 (0.176 mL, 1.4 mmol) were added to benzyl ether 20a
(64 mg, 0.14 mmol) in CH2Cl2 (1.8 mL). After 8 h at room
temperature, reaction mixture was concentrated and purified by
column chromatography (SiO2, 1:10, MeOH:CH2Cl2) to afford
1
phenol 21a as an amorphous solid (45 mg, 0.12 mmol, 86%). H
NMR (500 MHz, CDCl3) δ 8.98 (s, 1H), 7.40−7.34 (q, J = 7.1, 6.2
Hz, 1H), 7.27 (d, J = 7.6 Hz, 1H), 7.10−7.01 (m, 2H), 6.96 (d, J = 9.4
Hz, 1H), 6.84−6.79 (dd, J = 8.5, 2.6 Hz, 1H), 6.68 (d, J = 2.6 Hz, 1H),
5.73−5.52 (m, 2H), 4.51−4.38 (dt, J = 9.9, 5.0 Hz, 1H), 2.88−2.77 (q,
J = 9.5, 7.9 Hz, 1H), 2.43 (d, J = 17.3 Hz, 1H), 2.34 (m, 2H), 2.18 (s,
1H), 1.77 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 170.5, 163.6−
161.7 (d, J = 244.0 Hz), 155.2, 144.2 (d, J = 7.6 Hz), 142.3, 130.8,
130.1 (d, J = 8.4 Hz), 128.2, 127.0, 125.0 (d, J = 2.2 Hz), 124.7, 116.5,
116.3 (d, J = 20.3 Hz), 115.9, 114.2 (d, J = 20.3 Hz, 49.6, 40.8, 35.5,
33.5, 23.2. HRMS (FAB) m/z [M + Na+] for C21H25FNO2Na:
348.1376; found, 348.1379.
N-(4′-Hydroxy-3″-(trifluoromethyl)-1,2,3,6-tetrahydro-[1,1′:2′,1″-
terphenyl]-2-yl)acetamide (21b). Followed same procedure as for
21a. 1H NMR (400 MHz, CDCl3) δ 9.20 (s, 1H), 7.66−7.56 (m, 4H),
7.29 (d, J = 8.5 Hz, 1H), 6.82−6.72 (d, J = 10.5 Hz, 1H), 6.65 (s, 1H),
5.65 (m, 1H), 5.54 (m, 1H), 5.21 (d, J = 9.7 Hz, 2H), 4.56−4.33 (m,
1H), 2.76−2.61 (m, 1H), 2.46−2.24 (m, 3H), 1.75 (s, 3H). 13C NMR
(100 MHz, CDCl3) δ 170.5, 155.3, 142.7, 142.0, 132.6, 130.8, 130 (q, J
= 32.5 Hz), 128.8, 128.4, 126.9, 126.0 (m), 124.7, 124.0 (m), 116.7,
116.0, 49.6, 40.9, 35.6, 33.5, 23.2. HRMS (FAB) m/z [M + Na+] for
C21H20F3NO2Na: calcd, 398.1344; found, 398.1346.
N-(4′-(Benzyloxy)-2′-hydroxy-1,2,3,6-tetrahydro-[1,1′-biphenyl]-
2-yl)acetamide (18). Catalytic amount of concd HCl (few drops) was
added to MOM protected phenol 17 (0.27 g, 0.71 mmol) in methanol
(7.1 mL) and stirred vigorously at 50 °C for overnight. Upon
completion the reaction, mixture was concentrated and residue was
purified by column chromatography (SiO2; 5:100, MeOH: CH2Cl2) to
1
afford phenol 18 (0.19 g, 81%). H NMR (400 MHz, CDCl3) δ 8.86
(s, 1H), 7.41−7.25 (m, 5H), 7.01 (d, J = 8.5 Hz, 1H), 6.73 (d, J = 2.4
Hz, 1H), 6.48 (d, J = 6.0 Hz, 1H), 5.73 (m, 1H), 5.65 (m, 1H), 4.96
(s, 2H), 4.26 (m, 1H), 3.42 (m, 1H), 2.55−2.12 (m, 4H), 1.98 (s, 3H).
13C NMR (100 MHz, CDCl3) δ 173.2, 158.3, 155.4, 136.9, 128.5,
128.0, 127.9, 127.6, 127.0, 123.9, 121.1, 107.2, 103.4, 69.9, 51.9, 50.0,
36.6, 31.6, 21.0. HRMS (FAB) m/z [M + Na+] for C21H23NO3Na:
calcd, 360.1576; found, 360.1571.
N-(4′-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetrahy-
dro-2H-pyran-2-yl)oxy)-3″-fluoro-1,2,3,6-tetrahydro-[1,1′:2′,1″-ter-
phenyl]-2-yl)acetamide: (22a). Followed the same noviose coupling
procedure as described above for 13a to afford 22a as a inseparable
2′-Acetamido-4-(benzyloxy)-1′,2′,3′,6′-tetrahydro-[1,1′-biphen-
yl]-2-yl trifluoromethanesulfonate (19). A solution of phenol (0.19 g,
0.58 mmol) in anhydrous CH2Cl2 (5.8 mL) and triethylamine (0.12
m L , 0 . 8 7 m m o l ) f o l l o w e d b y N - p h e n y l - b i s -
(trifluoromethanesulfonimide) (0.31 g, 0.87 mmol) were added at 0
°C. Upon completion, the reaction was quenched by addition of water
(50 mL), washed with saturated aqueous NaCl solution, dried
(Na2SO4), filtered, and concentrated. The residue was purified by
column chromatography (SiO2, 3:1, Hex:EtOAc) to afford triflate 19
1
mixture of diastereomers. H NMR (500 MHz, CDCl3) δ 7.32 (ddd,
1H, J = 6.0, 7.9, 13.9 Hz), 7.22 (dd, 1H, J = 2.8, 8.7 Hz), 7.00 (m, 2H),
6.94 (d, 1H, J = 7.6 Hz), 6.87 (m, 1H), 6.77 (dd, 1H, J = 2.7, 8.7 Hz),
5.59 (m, 1H), 5.52 (m, 1H), 5.49 (d, 1/2H, J = 2.4 Hz), 5.45 (d, 1/
2H, J = 2.4 Hz), 4.81 (dd, 1H, J = 2.5, 8.8 Hz), 4.21 (m, 1H), 4.12 (m,
1H), 4.07 (m, 1H), 3.52 (s, 3H), 3.25 (dd, 1H, J = 0.9, 9.0 Hz), 2.89
(br s, 1H), 2.76 (m, 1H), 2.67 (s, 1H), 2.26 (m, 2H), 1.69 (m, 1H),
1.65 (s, 3/2H), 1.64 (s, 3/2H), 1.29 (s, 3/2H), 1.28 (s, 3/2H), 1.13 (s,
3/2H), 1.12 (s, 3/2H). 13C NMR (125 MHz, CDCl3) δ 169.4, 169.4,
163.7−161.7 (d, J = 249.0 Hz), 154.9, 154.7, 143.0 (dd, J = 1.7, 8.5
Hz), 142.2 (d, J = 1.7 Hz), 133.4, 133.3, 130.2 (dd, J = 1.7, 8.5 Hz),
128.4 (d, J = 5.0 Hz), 126.6 (d, J = 3.2 Hz), 125.1 (d, J = 3.6 Hz),
125.0 (m), 117.2, 116.9, 116.6, 116.3 (dd, J = 13.4, 20.9 Hz), 116.2,
114.3 (dd, J = 1.5, 20.9 Hz), 98.0, 97.7, 84.5, 84.4, 78.3, 78.3, 77.4,
71.5, 71.4, 68.8, 62.0, 61.9, 49.6, 49.6, 40.5, 40.5, 35.2, 35.1, 33.4, 29.2,
23.6, 23.5, 23.2, 23.1. HRMS (FAB) m/z [M + Na+] for
C28H34FNO6Na: 522.2262; found, 522.2267.
1
as a pale-yellow oil (0.23 g, 0.49 mmol, 85%). H NMR (400 MHz,
CDCl3) δ 7.45−7.31 (m, 6H), 7.00 (d, J = 11.2 Hz, 1H), 6.84 (d, J =
2.4 Hz, 1H), 5.70 (m, 2H), 5.60 (d, J = 9.3 Hz, 1H), 5.04 (s, 2H),
4.53−4.38 (dt, J = 15.2, 10.2 Hz, 1H), 3.18−3.03 (td, J = 11.2, 5.2 Hz,
1H), 2.63−2.50 (dd, J = 16.2, 4.2 Hz, 1H), 2.42−2.32 (m, 1H), 2.28−
2.15 (m, 1H), 2.11−1.97 (t, J = 14.5 Hz, 1H), 1.71 (s, 3H). 13C NMR
(100 MHz, CDCl3) δ 169.7, 158.2, 147.6, 136.0, 129.9, 128.8, 128.5,
128.1, 127.7, 126.1, 125.4, 115.8, 108.2, 70.7, 48.3, 38.5, 34.8, 33.7,
23.2. HRMS (FAB) m/z [M + Na+] for C22H22F3NO5SNa: calcd,
492.106318; found, 492.1067.
N-(4′-(Benzyloxy)-3″-fluoro-1,2,3,6-tetrahydro-[1,1′:2′,1″-ter-
phenyl]-2-yl)acetamide (20a). Followed same Suzuki coupling
1
procedure as described above for 8a. H NMR (400 MHz, CDCl3)
N-(4′-(((3R,4S,5R)-3,4-Dihydroxy-5-methoxy-6,6-dimethyltetrahy-
dro-2H-pyran-2-yl)oxy)-3″-(trifluoromethyl)-1,2,3,6-tetrahydro-
[1,1′:2′,1″-terphenyl]-2-yl)acetamide (22b). Followed the same
noviose coupling procedure as described above for 13a to afford
δ 7.47−7.30 (m, 7H), 7.13−7.05 (t, J = 8.9 Hz, 1H), 7.05−7.00 (t, J =
7.2 Hz, 2H), 6.97 (d, J = 10.9 Hz, 1H), 6.80 (d, J = 2.7 Hz, 1H), 5.72−
5.53 (m, 2H), 5.06 (s, 2H), 4.91 (d, J = 8.7 Hz, 1H), 4.36−4.24 (m,
1H), 2.90−2.75 (dd, J = 19.2, 8.2 Hz, 1H), 2.59−2.45 (dt, J = 16.3, 4.4
Hz, 1H), 2.36 (m, 2H), 1.75 (s, 3H). 13C NMR (100 MHz, CDCl3) δ
169.3, 156.8, 143.9, 142.3, 137.0, 132.6, 130.2, 130.2, 128.8, 128.5,
128.2, 127.8, 126.7, 125.2, 125.0, 116.4, 116.2, 116.0, 115.2, 114.5,
114.3, 70.2, 49.4, 40.5, 35.3, 33.4, 23.5. HRMS (FAB) m/z [M + Na+]
for C27H26FNO2Na: calcd, 438.1840; found, 438.1818.
1
22b as a inseparable mixture of diastereomers. H NMR (500 MHz,
CDCl3) δ 7.65 (d, 1H, J = 8.2 Hz), 7.56 (t, 1H, J = 7.7 Hz), 7.49 (s,
1H), 7.45 (d, 1H, J = 7.6 Hz), 7.32 (dd, 1H, J = 3.0, 8.7 Hz), 7.08 (td,
1H, J = 2.7, 8.6 Hz), 6.85 (dd, 1H, J = 2.7, 8.5 Hz), 5.65 (m, 1H), 5.59
(m, 1H), 5.57 (d, 1/2H, J = 2.4 Hz), 5.53 (d, 1/2H, J = 2.3 Hz), 4.90
(t, 1H, J = 8.2 Hz), 4.30 (m, 1H), 4.19 (dd, 1H, J = 4.3, 8.2 Hz), 4.14
(m, 1H), 3.59 (s, 3/2H), 3.59 (s, 3/2H), 3.33 (d, 1H, J = 9.0 Hz), 3.17
(s, 1H), 2.95 (s, 1H), 2.76 (m, 1H), 2.49 (m, 1H), 2.33 (m, 1H), 1.74
(m, 1H), 1.73 (s, 3/2H), 1.72 (s, 3/2H), 1.36 (s, 3/2H), 1.35 (s, 3/
2H), 1.21 (s, 3/2H), 1.20 (s, 3/2H). 13C NMR (100 MHz, CDCl3) δ
169.4, 169.4, 155.0, 154.8, 142.3, 141.8, 133.4, 133.3, 132.8, 132.6,
131.8 (dq, J = 2.2, 32.5 Hz), 129.1, 128.6, 126.5, 125.9 (q, J = 3.2, 7.0
Hz), 125.0, 124.2, 117.6, 117.0, 116.8, 98.1, 97.8, 84.5, 84.4, 78.4, 78.3,
N-(4′-(Benzyloxy)-3″-(trifluoromethyl)-1,2,3,6-tetrahydro-
[1,1′:2′,1″-terphenyl]-2-yl)acetamide (20b). Followed same Suzuki
1
coupling procedure as described above for 8a. H NMR (400 MHz,
CDCl3) δ 7.73−7.30 (m, 10H), 7.05 (d, J = 8.7 Hz, 1H), 6.85 (s, 1H),
5.66 (m, 2H), 5.16 (d, J = 8.5 Hz, 1H), 5.08 (s, 2H), 4.43−4.29 (m,
1H), 2.90−2.74 (q, J = 10.0, 9.0 Hz, 1H), 2.50 (d, J = 17.7 Hz, 1H),
2.40−2.28 (dd, J = 6.9, 3.9 Hz, 2H), 1.75 (s, 3H). 13C NMR (101
5810
dx.doi.org/10.1021/jm300544c | J. Med. Chem. 2012, 55, 5797−5812

Journal of Medicinal Chemistry
Article
71.3, 71.3, 68.7, 68.7, 61.9, 61.9, 49.4, 49.3, 40.5, 40.5, 35.1, 35.0, 33.1,
29.0, 29.0, 23.4, 23.4, 23.1, 23.0. HRMS (FAB) m/z [M + Na+] for
C29H34F3NO6Na: Calcd, 572.2230; found, 572.2227.
(10) Urban, M. J.; Li, C.; Yu, C.; Lu, Y.; Krise, J. M.; McIntosh, M. P.;
Rajewski, R. A.; Blagg, B. S. J.; Dobrowsky, R. T. Inhibiting Heat
Shock Protein 90 Reverses Sensory Hypoalgesia in Diabetic Mice.
ASN Neuro 2010, 2, 189−199.
(11) Burlison, J. A.; Avila, C.; Vielhauer, G.; Lubbers, D. J.;
Holzbeierlein, J.; Blagg, B. S. Development of novobiocin analogues
that manifest anti-proliferative activity against several cancer cell lines.
J. Org. Chem. 2008, 73 (6), 2130−2137.
(12) Donnelly, A. C.; Mays, J. R.; Burlison, J. A.; Nelson, J. T.;
Vielhauer, G.; Holzbeierlein, J.; Blagg, B. S. J. The Design, Synthesis,
and Evaluation of Coumarin Ring Derivatives of the Novobiocin
Scaffold that Exhibit Antiproliferative Activity. J. Org. Chem. 2008, 73
(22), 8901−8920.
(13) Matts, R. L.; Dixit, A.; Peterson, L. B.; Sun, L.; Voruganti, S.;
Kalyanaraman, P.; Hartson, S. D.; Verkhivker, G. M.; Blagg, B. S. J.
Elucidation of the Hsp90 C-Terminal Inhibitor Binding Site. ACS
Chem. Biol. 2011, 6, 800−807.
(14) Lee, M.; Gubernator, N. G.; Sulzer, D.; Sames, D. Development
of pH-Responsive Fluorescent False Neurotransmitters. J. Am. Chem.
Soc. 2010, 132 (26), 8828−8830.
(15) Grasa, G. A.; Viciu, M. S.; Huang, J.; Zhang, C.; Trudell, M. L.;
Nolan, S. P. Suzuki−Miyaura Cross-Coupling Reactions Mediated by
Palladium/Imidazolium Salt Systems. Organometallics 2002, 21 (14),
2866−2873.
(16) Olson, J. P.; Gichinga, M. G.; Butala, E.; Navarro, H. A.;
Gilmour, B. P.; Carroll, F. I. Synthesis and evaluation of 1,2,4-
methyltriazines as mGluR5 antagonists. Org. Biomol. Chem. 2011, 9
(11), 4276−4286.
(17) Fuganti, C.; Sacchetti, A. Biocatalytic enantioselective approach
to 3-aryl-2-nitropropanols: synthesis of enantioenriched (R)-5-
methoxy-3-aminochroman, a key precursor to the antidepressant
drug Robalzotan. J. Mol. Catal. B: Enzym. 2010, 66 (3−4), 276−284.
(18) Wood, K.; Black, D. S.; Kumar, N. Ring closing metathesis
strategies towards functionalised 1,7-annulated 4,6-dimethoxyindoles.
Tetrahedron 2011, 67 (22), 4093−4102.
(19) Kusuma, B. R.; Peterson, L. B.; Zhao, H.; Vielhauer, G.;
Holzbeierlein, J.; Blagg, B. S. J. Targeting the Heat Shock Protein 90
Dimer with Dimeric Inhibitors. J. Med. Chem. 2011, 54 (18), 6234−
6253.
(20) Oozeki, H.; Tajima, R.; Nihei, K-I. Molecular design of potent
tyrosinase inhibitors having the bibenzyl skeleton. Bioorg. Med. Chem.
Lett. 2008, 18, 5252−5254.
(21) Bryce, M. R.; Gardiner, J. M. Functionalised ( )-cephalotaxine
analogues. J. Chem. Soc., Chem. Commun. 1989, 16, 1162−1164.
(22) Pei, Z.; Li, X.; von Geldern, T. W.; Madar, D. J.; Longenecker,
K.; Yong, H.; Lubben, T. H.; Stewart, K. D.; Zinker, B. A.; Backes, B.
J.; Judd, A. S.; Mulhern, M.; Ballaron, S. J.; Stashko, M. A.; Mika, A. K.;
Beno, D. W. A.; Reinhart, G. A.; Fryer, R. M.; Preusser, L. C.; Kempf-
Grote, A. J.; Sham, H. L.; Trevillyan, J. M. Discovery of ((4R,5S)-5-
Amino-4-(2,4,5-trifluorophenyl)cyclohex-1-enyl)-(3- (trifluorometh-
yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone
(ABT-341), a Highly Potent, Selective, Orally Efficacious, and Safe
Dipeptidyl Peptidase IV Inhibitor for the Treatment of Type 2
Diabetes. J. Med. Chem. 2006, 49 (22), 6439−6442.
(23) Andrieux, C. P.; Farriol, M.; Gallardo, I.; Marquet, J.
Thermodynamics and kinetics of homolytic cleavage of carbon−
oxygen bonds in radical anions obtained by electrochemical reduction
of alkyl aryl ethers. J. Chem. Soc., Perkin Trans. 2 2002, No. 5, 985−
990.
ASSOCIATED CONTENT
■
S
* Supporting Information
1H and 13C NMR spectra for all new compounds and HPLC
traces for most active compounds. This material is available free
of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
■
*Phone: (785) 864-2288. Fax: (785) 864-5326. E-mail:
bblagg@ku.edu..
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by grants from The National
Institutes of Health to B.S.J.B. [CA120458, CA109265],
R.T.D. [NS054847, DK073594] and B.S.J.B. and R.T.D.
[NS075311] and by the Juvenile Diabetes Research Foundation
(R.T.D.).
ABBREVIATIONS USED
■
DPN, diabetic peripheral neuropathy; DNA, deoxyribonucleic
acid; SAR, structure−activity relationships; AGEs, advanced
glycation end products enhanced oxidative stress; Hsp90 and
Hsp70, heat shock protein 90 and 70
REFERENCES
■
(1) Veves, A.; Backonja, M.; Malik, R. A. Painful diabetic neuropathy:
epidemiology, natural history, early diagnosis, and treatment options.
Pain Med. 2008, 9, 660−674.
(2) Tomlinson, D. R.; Gardiner, N. J. Glucose neurotoxicity. Nature
Rev. Neurosci. 2008, 9 (1), 36−45.
(3) Mayer, M. P.; Bukau, B. Hsp70 chaperones: cellular functions and
molecular mechanism. Cell. Mol. Life Sci. 2005, 62 (6), 670−84.
(4) Peterson, L. B.; Blagg, B. S. To fold or not to fold: modulation
and consequences of Hsp90 inhibition. Future Med. Chem. 2009, 1 (2),
267−283.
(5) Burlison, J. A.; Neckers, L.; Smith, A. B.; Maxwell, A.; Blagg, B. S.
J. Novobiocin: Redesigning a DNA Gyrase Inhibitor for Selective
Inhibition of Hsp90. J. Am. Chem. Soc. 2006, 128, 15529−15536.
(6) (a) Zhang, L.; Yu, C.; Vasquez, F. E.; Galeva, N.; Onyango, I.;
Swerdlow, R. H.; Dobrowsky, R. T. Hyperglycemia alters the schwann
cell mitochondrial proteome and decreases coupled respiration in the
absence of superoxide production. J. Proteome Res. 2010, 9 (1), 458−
471. (b) Zhang, L.; Zhao, H.; Blagg, B. S.; Dobrowsky, R. T.; C-
Terminal, A Heat Shock Protein 90 Inhibitor Decreases Hyper-
glycemia-induced Oxidative Stress and Improves Mitochondrial
Bioenergetics in Sensory Neurons. J. Proteome Res. 2012, 11, 129−137.
(7) (a) Obrosova, I. G. Diabetes and the peripheral nerve. Biochim.
Biophys. Acta 2009, 10, 931−940. (b) Akude, E.; Zherebitskaya, E.;
Roy Chowdhury, S. K.; Girling, K.; Fernyhough, P. 4-Hydroxy-2-
Nonenal Induces Mitochondrial Dysfunction and Aberrant Axonal
Outgrowth in Adult Sensory Neurons that Mimics Features of
Diabetic Neuropathy. Neurotox. Res. 2009, 1, 28−38.
(8) Muchowski, P. J.; Wacker, J. L. Modulation of neurodegeneration
by molecular chaperones. Nature Rev. Neurosci. 2005, 6 (1), 11−22.
(9) Baseler, W. A.; Dabkowski, E. R.; Williamson, C. L.; Croston, T.
L.; Thapa, D.; Powell, M. J.; Razunguzwa, T. T.; Hollander, J. M.
Proteomic alterations of distinct mitochondrial subpopulations in the
type 1 diabetic heart: contribution of protein import dysfunction. Am.
J. Physiol.: Regul. Integr. Comp. Physiol. 2011, 300 (2), R186−200.
(24) Calamini, B.; Silva, M. C.; Madoux, F.; Hutt, D. M.; Khanna, S.;
Chalfant, M. A.; Saldanha, S. A.; Hodder, P.; Tait, B. D.; Garza, D.;
Balch, W. E.; Morimoto, R. I. Small-molecule proteostasis regulators
for protein conformational diseases. Nature Chem. Biol. 2012, 8 (2),
185−196.
(25) Chen, W.; Mi, R.; Haughey, N.; Oz, M.; Hoke, A.
̈
Immortalization and characterization of a nociceptive dorsal root
ganglion sensory neuronal line. J. Peripher. Nerv. Syst. 2007, 12 (2),
121−130.
5811
dx.doi.org/10.1021/jm300544c | J. Med. Chem. 2012, 55, 5797−5812

Journal of Medicinal Chemistry
Article
(26) Zhang, L.; Zhao, H.; Blagg, B. S. J.; Dobrowsky, R. T. C-
Terminal Heat Shock Protein 90 Inhibitor Decreases Hyperglycemia-
Induced Oxidative Stress and Improves Mitochondrial Bioenergetics in
Sensory Neurons. J. Proteome Res. 2012, 11, 2581−2593.
(27) Vincent, A. M.; Kato, K.; McLean, L. L.; Soules, M. E.; Feldman,
E. L. Sensory Neurons and Schwann Cells Respond to Oxidative Stress
by Increasing Antioxidant Defense Mechanisms. Antioxid. Redox
Signaling 2009, 11, 425−438.
(28) Vincent, A. M.; Stevens, M. J.; Backus, C.; McLean, L. L.;
Feldman, E. L. Cell culture modeling to test therapies against
hyperglycemia-mediated oxidative stress and injury. Antioxid. Redox
Signaling 2005, 7 (11−12), 1494−1506.
5812
dx.doi.org/10.1021/jm300544c | J. Med. Chem. 2012, 55, 5797−5812