Design, synthesis and evaluation of novel hydroxyamides as orally available anticonvulsants

Article abstract of DOI:10.1016/j.bmc.2003.12.011

Themisone, also known as Atrolactamide, was found, in the 1950s, to be a very potent anticonvulsant. It was hypothesized that the -CF₃ substitution would maintain the anticonvulsant activity. Anticonvulsant testing of our novel compounds by the

Full text of DOI:10.1016/j.bmc.2003.12.011

Bioorganic & Medicinal Chemistry 12 (2004) 979–993
Design, synthesis and evaluation of novel hydroxyamides as
orally available anticonvulsants
Hilary A. Schenck,a Paul W. Lenkowski,a Indrani Choudhury-Mukherjee,a
Seong-Hoon Ko,b James P. Stables,c Manoj K. Patelb and Milton L. Browna,*
aDepartments of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
bDepartment of Anesthesiology, University of Virginia, Charlottesville, VA 22908, USA
cNational Institute of Health, Division of Neurological Disease and Stroke, Bethesda, MD 20824, USA
Received 15 August 2003; revised 11 December 2003; accepted 12 December 2003
Abstract—Themisone, also known as Atrolactamide, was found, in the 1950s, to be a very potent anticonvulsant. It was hypo-
thesized that the -CF3 substitution would maintain the anticonvulsant activity. Anticonvulsant testing of our novel compounds by
the National Institute of Health’s Anticonvulsant Screening Project of the Antiepileptic Drug Discovery Program identified ana-
logue 1, 3,3,3-trifluoro-2-hydroxy-2-phenyl-propionamide, to have potent anticonvulsant activity (MES ED50 of 9.9 mg/kg,
ScMET ED50 of 34 mg/kg and TD50 of 100 mg/kg). Therefore, a diverse range of analogues were synthesized utilizing multiple
synthetic pathways to explore the structure–activity relationship. Patch clamp electrophysiology experiments demonstrate that
compound 1 is an effective T-type calcium channel blocker. Altogether, these results suggest these compounds as a class of orally
available anticonvulsants.
# 2003 Published by Elsevier Ltd.
neuronal voltage-dependent sodium channels (NVSC),2
1. Introduction
g-aminobutyric acid (GABA),3 voltage-dependent cal-
Epilepsy is a neurological disorder of brain function
seen by the periodic and unpredictable occurrence of
seizures. There have already been 40 types of epilepsy
characterized in patients. Numerous types of epileptic
seizures occur, with frequency and type differing in each
patient, often making it difficult for one drug to help all
patients. Approximately 30% of the medicated epileptic
patients do not have complete control of their seizures
and may require medication for the duration of their
life. There are also numerous side effects associated with
even the most common anticonvulsant drugs available.1
Specifically, there is a need for new medications that are
devoid of side effects.
cium channels (VDCC), especially the T-type current,1
and N-methyl-d-aspartate (NMDA) receptors. Recent
evidence has also lead to the application of ligands
competing with glutamate binding on alpha-amino-3-
hydroxy-5-methyl-4-isoxazole propionate (AMPA) and
kianic acid (KA) to minimize symptoms of epilepsy.4
Calcium channels are the primary route for translating
electrical signals into the biochemical events underlying
key processes such as neurotransmitter release, cell
excitability, and gene expression. In addition to the
neuronal voltage gated sodium channel, T-type or low
voltage activated (LVA) calcium channels such as
Cav3.2 are thought to contribute to neuronal excit-
ability and are important targets for the treatment of
epilepsy.5 These channels are thought to contribute to
the oscillatory firing of neurons in the thalamus and
dysrhythmias in this region can lead to epilepsy.6 Fur-
thermore, calcium channels enhance postsynaptic
responses in somatodendrites and re-excitation follow-
ing periods of bursting which is believed to be related to
epilepsy.7,8 There has also been evidence of activation of
VDCC’s triggering changes in gene expression.9 Thus,
The drug treatment of epilepsy is accomplished with the
use of anticonvulsants. Common mechanisms, which
can be exploited in the treatment of epilepsy, include
Keywords: Amides; Alcohols; Ion channel; Calcium channel.
* Corresponding author. Department of Chemistry, University of
Virginia, McCormick Road, PO Box 400319, Charlottesville, VA
22904, USA.
0968-0896/$ - see front matter # 2003 Published by Elsevier Ltd.
doi:10.1016/j.bmc.2003.12.011

980
H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
Scheme 1.
we sought to examine the ability of these novel anti-
convulsants to block T-type calcium channels.
minimal clonic phase was observed, followed by stereo-
typed, automatistic behavior. The model examines the
compounds’ ability to stop the spread of seizures. The
petite mal model was conducted with a subcutaneous
pentylenetetrazol seizure threshold (scMet) test. The
animals were injected with a convulsant dose of penty-
lenetetrazol at the peak effect time of the compound.
This model measured the compounds’ threshold for sei-
zures. Results were expressed as the number of animals
protected out of the number of animals tested at differ-
ent time intervals. A neuronal toxicity test (TOX) was
performed where the animals walk on a spinning rod (6
rpm) for varying lengths of time to check for the loss of
righting reflex or other toxic effects. Normal mice can
remain on a rod rotating at this speed indefinitely.
Neurotoxicity was noted when the animal failed to
remain on the rod for one min. Phase I of each com-
pound occurs at 30, 100 and 300 mg/kg of the test
compounds when challenged by each model at 15 to 30
min intervals up to 4 h. Compounds which demon-
strated profound activity were evaluated in Phase II for
ED50 and TD50 quantification in mice, which required
an additional 1000 mg of the compound.12
The development of our lead compound 1 was based
upon the toxicity found in Themisone. Fluorination of
this compound was originally designed by us in an effort
to avoid the potential formation of the toxin phenyl-
acylamide.10,11 Utilizing traditional medicinal chemistry
transformations, we designed a series of compounds to
explore the SAR of stepwise changes in electronic and
conformational properties of 1 on anticonvulsant activity.
2. Results
All compounds were synthesized and 300 mg of each
were sent to the National Institute of Health’s Anti-
convulsant Screening Project of the Antiepileptic Drug
Discovery Program (NINDS ADD program). NIH
performs anticonvulsant testing (oral and intraperi-
toneal, ip) on both mice and rats in phase I trials. The
grand mal model was conducted with a maximal elec-
troshock (MES) test, where corneal electrode implants
are primed with a drop of electrolyte solution and an
electrical stimulus was delivered for 0.2 s to elicit a psy-
chomotor seizure. Typically, a seizure was noted when a
Anticonvulsant evaluation of compound 1 administered
intraperitoneally in mice demonstrated complete (3/3
Table 1. Phase I rat anticonvulsant activity (po.)
MES
30 mg/kg drug
Rotorod
30 mg/kg drug
Compd
0.25 h
0.50 h
1.0 h
2 h
4 h
0.25 h
0.50 h
1 h
2 h
4.0 h
1
8
4/4
3/4
0/4
1/4
0/4
0/4
1/4
0/3
1/4
4/4
1/4
2/4
2/4
4/4
0/4
1/4
2/4
1/4
0/4
1/4
2/3
2/4
3/4
1/4
2/4
1/4
4/4
3/4
0/4
3/4
1/4
0/4
1/4
2/3
1/4
3/4
0/4
3/4
2/4
4/4
1/4
2/4
1/4
1/4
1/4
1/4
2/3
4/4
3/4
0/4
2/4
2/4
4/4
0/4
2/4
1/4
1/4
0/4
1/4
3/3
3/4
4/4
2/4
4/4
2/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/3
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/3
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/3
0/4
0/4
0/4
2/4a
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/3
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/3
0/4
0/4
0/4
0/4
0/4
10
12
40
44
45
46
47
48
53
54
55
a Wild running.

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
981
Scheme 2.
Scheme 3.
mice) protection at a dose of 100 mg/kg up to 4 h when
challenged with MES (Table 2). Compound 1 also
demonstrated effectiveness against scMet (5/5 mice pro-
tected) for 0.5 h at the same dose. At a 100 mg/kg dose,
50% of the mice were unable to grasp the rotating rod
and exhibited the loss of the righting reflex upon falling
off the rod. Phase II trials evaluated the compound for
the ED50’s in both models and the TD50 with the com-
pound administrated orally (po). The MES ED50 was
found to be 9.9 mg/kg, the ScMET ED50 was 34 mg/kg
and the TD50 noted at 100 mg/kg, yielding a therapeutic
index of 10 for the MES model and 2.6 for the ScMET
model (Table 4). Analogue 53’s MES ED50 was also
determined to be 62.4 mg/kg but has notably longer
lasting effects (up to 6 h, see Table 3) and a TD50 over
100 mg/kg. Analogue 1 was notably able to provide
protection of up to 4 h at 100 mg/kg. Comparisons with
phenytoin demonstrated significantly improved broad
spectrum coverage in the model with little change in
MES protection.13 Serendipitously, anesthesia was
noted as a toxicity at the 300 mg/kg dose at 4 h in 2 out
of 2 animals. Compound 1 was then tested indepen-
dently for general anesthesic activity and was found to
lower the minimum alveolar concentration of isoflurane
by 33% at 60 mg/kg.13
uated for their anticonvulsant activity. The general syn-
thetic methods are shown in Schemes 1–7. Final
products 1, 7–10, 18, 38–48, 50, and 58 were synthesized
by converting the corresponding ketones to the tri-
methylsilyl ether with trimethylsilyl cyanide (TMSCN).
Subsequent hydrolysis with 15% HCl generated the
cyanohydrin. Conversion of the corresponding cyano-
hydrin to the hydroxyamide was accomplished under
acidic conditions, by saturating with HCl gas and
allowing the mixtures to stand at room temperature for
16 h.14 The trifluoromethyl ketones 20–26 were
obtained from formation of the corresponding Grignard
reagent from their aromatic bromide and adding 2,2,2-
Trifluro-1-piperidin-1-yl-ethanone 19 to introduce the
fluorine (Scheme 3).15 Analogue 1 was heated at 100 ꢀC
for 24 h in concentrated HCl to obtain 13, the acid of
the lead compound (Scheme 1). Analogue 12 was syn-
thesized from the reduction of compound 2 with
LiAlH4.16 Compound 18 was synthesized by reacting
dimethylhydrazine with benzaldehyde to give the N0-
Benzylidene-N,N-dimethyl-hydrazone 14. Addition of
the anhydride generated the methyl-(3,3,3-trifluoro-1-
phenyl-propenyl)-diazene 15. Intermediate 15 was con-
verted to the 3,3,3-Trifluoro-1-phenyl-propan-1-one 16
under acidic conditions (Scheme 2).17 TMSCN was
added to the ketone 16 to produce the cyanohydrin and
finally to the hydroxyamide using the method discussed
above. Compound 50 was synthesized using the
With the emergent anticonvulsant activity of compound
1 other analogues were designed, synthesized and eval-

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H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
Table 2. Phase I mouse anticonvulsant activity (ip)
MES
30 mg/kg drug
ScMET
30 mg/kg drug
Rotorod
30 mg/kg drug
Compd
Dosage
(mg/kg)
0.50 h
4 h
0.50 h
4 h
0.5 h
4 h
1
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
0/1
3/3
1/1
0/1
1/1
n/a
0/1
0/3
1/1
0/1
0/3
0/1
0/1
1/3
1/1
0/1
1/3
1/1
0/1
3/3
1/1
0/1
0/3
0/1
0/1
1/3
1/1
0/1
3/3
n/a
0/1
0/3
1/1
0/1
1/3
1/1
0/1
0/3
n/a
0/1
0/3
n/a
0/1
1/3
n/a
0/1
0/3
1/1
0/1
0/3
n/a
0/1
3/3
0/0
0/1
0/3
1/1
0/1
3/3
1/1
0/1
2/3
n/a
0/1
2/3
1/1
0/1
0/1
3/3
1/1
0/1
0/0
n/a
0/1
0/3
0/1
0/1
0/3
0/0
0/1
0/3
0/1
0/1
0/3
0/0
0/1
0/3
1/1
0/1
0/3
0/1
0/1
1/3
1/1
0/1
3/3
n/a
0/1
0/3
0/1
0/1
0/3
0/1
0/1
0/3
n/a
0/1
0/3
n/a
0/1
0/3
n/a
0/1
2/3
1/1
0/1
1/3
n/a
0/1
3/3
1/1
0/2
0/3
n/a
0/1
2/3
1/1
0/1
1/3
n/a
0/1
3/3
1/1
0/1
0/1
5/5
1/1
0/1
n/a
n/a
0/1
0/1
1/1
0/1
0/1
1/1
0/1
0/1
1/1
0/1
4/5
1/1
0/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
1/1
n/a
0/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
n/a
0/1
0/1
0/1
0/1
0/1
n/a
0/1
0/1
1/1
0/1
4/4e
0/0
2/5
1/1
n/a
0/1
5/5
n/a
0/1
0/1
1/1
0/1
1/1
n/a
0/1
0/1
1/1
2/5
0/1
0/1
1/1
2/5
n/a
n/a
0/1
0/1
0/1
0/1
0/1
0/0
0/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
3/5
n/a
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
n/a
0/1
0/1
n/a
0/1
0/1
n/a
0/1
1/1
1/1
0/1
1/1
1/1
0/1
1/1
n/a
0/1
1/1
n/a
0/1
0/1
1/1
0/1
0/1
n/a
0/1
0/1
1/1
0/1
0/4
4/8
4/4b
0/4
8/8
4/4d
0/4
2/8
4/4a
0/4
5/8
4/4
0/4
0/8
2/4
0/4
4/8
4/4b
0/4
1/8
4/4a
0/4
0/8
0/4
0/4
2/8
4/4a
1/4
6/8a
4/4d
0/4
0/8
4/4
0/4
0/8
4/4b
0/4
0/8
4/4d
0/4
0/8
4/4
0/4
1/8
4/4d
0/4
4/8
4/4a
0/4
6/8
4/4d
0/4
6/8
4/4
0/4
7/8a
4/4
0/4
4/8a
4/4a
0/4
6/8
4/4
0/4
0/8
4/4a
0/4
0/2
2/4a
2/2c
0/2
n/a
n/a
0/2
0/4
0/2
0/2
0/4
1/1d
0/2
0/4
0/2
0/2
0/4
2/2d
0/2
0/4
0/2
0/2
0/4
1/2
0/2
0/4
2/2
0/2
2/4
n/a
0/2
0/4
0/2
0/2
0/4
0/2
0/2
0/4
n/a
0/2
0/4
n/a
0/2
0/4
n/a
0/2
1/4
2/2a
0/2
3/4
1/1a
0/2
0/4
1/1a
0/2
3/4a
n/a
0/2
1/4
2/2b
0/2
0/4
n/a
0/2
0/4
2/2a
0/2
7
8
9
10
11
12
13
18
38
39
40
41
42
43
44
45
46
47
48
50
53
54
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
100
300
30
(continued on next page)

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
983
Table 2 (continued)
MES
30 mg/kg drug
ScMET
30 mg/kg drug
Rotorod
30 mg/kg drug
Compd
Dosage
(mg/kg)
0.50 h
4 h
0.50 h
4 h
0.5 h
4 h
100
300
30
100
300
30
3/3
1/1
0/1
3/3
1/1
0/1
0/3
0/1
2/3
1/1
0/1
0/3
1/1
0/1
0/3
0/1
1/1
1/1
1/5
0/1
1/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
1/1
0/1
0/1
0/1
8/8a
4/4b
0/4
0/4
2/2b
0/2
0/4
1/2
0/2
0/4
0/2
55
58
1/8
4/4a
0/4
100
300
0/8
0/4
a Unable to grasp rotorod.
b Loss of righting reflex.
c Anesthesia.
d Death.
e 1/5 died during test without having a seizure.
Scheme 4.
Scheme 5.
Our previous demonstration that phenylhydroxyamides
bind to the hydantoin-anesthetic binding site in the
NVSC,21 led us to evaluate this mechanism for
these similar compounds. We evaluated the effects
of 10 and 100 mM of analogue 1 on rNaV 1.3
expressed in xenopus oocytes. The results of this
study suggested that analogue 1 did not block voltage
gated Na+ channels. The specific binding of labeled
batrachotoxinin-A 20-a-benzoate ([3H]BTX-B)22 to
voltage-sensitive sodium channels was also tested and it
was found that compound 1 inhibited BTX at 6.78% at
40 mM.
Scheme 6.
standard conditions for formation of an a-hydroxyamide
from the commercially available ketone (Scheme 4).
Compound 1’s tertiary alcohol was silylated to allow for
methylation of the amide with NaH and methyl iodide.
Removal of the silyl protecting group with TBAF
resulted in analogue 53 (Scheme 5). Compound 54 was
obtained from the direct methylation of 1 with NaH
and methyl iodide.18 The synthesis of analogue 55 was
accomplished by treating methyl-isatin with trimethyl
(trifluoromethyl)silane (TMSCF3) to generate the TMS
ether (Scheme 6) and the TMS ethers were hydrolyzed
with acid to obtain the final products.19 Ketone 56
resulted from the palladium-catalyzed cross coupling of
phenyl trifluoroacetate and 2-Naphthaleneboronic
acid,20 followed by formation of the cyanohydrin and
finally the hydroxyamide (Scheme 7).
Other mechanisms of action thus far include several
subtypes of K+ channels. Compound 1 did not activate
or inhibit rat TASK-1 and TASK-3 leak K+ channels
expressed in HEK293 cells at 100 mM.
Several anticonvulsant agents enhance GABAA receptor
currents. It was therefore important to evaluate effects
of compound 1 on GABAA receptors in rat hippo-
campal neurons. Hippocampal neurons in culture for
10–14 days were studied with whole-cell patch clamp
recording technique. Application of 1 mM of compound
1 was found to accentuate the GABA current elicited by
GABA at 10 mM.23

984
H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
Scheme 7.
Table 3. Phase I administration of compound 53 in rats at 100 mg/kg
(po)
4.0 h
6.0 h
MES
TOX
4/4
0/4
4/4
0/4
Table 4. Phase II administration of drugs in rats (p.o.)
Compd
MES ED50
ScMET ED50 Rotorod TD50
T.I.b
1
9.92 mg/kg
(6.9–13.4)a
62.39 mg/kg
(44.56–80.62)a
38.57 mg/kg
(24.6–51.9)
N/A
100 mg/kg
MES 10.0
ScMET 2.6
>100 mg/kg MES >1.6
53
a ( )95% confidence level.
b T.I.=therapeutic index.
Figure 1. Use dependent blockade of hCav3.2 channels by compounds
1, 53 and 54. Cells were held at ꢂ110 mV and a step to ꢂ20 mV for
150 ms was applied, this was repeated at a 1 Hz stimulation frequency.
Under control conditions, there is a distinctive use dependent decrease
in calcium current that reached steady state within the first 10 seconds.
In the presence 1 mM of compounds 1 or 53 the inactivation fails to
stabilize, and current continues to decrease with subsequent stimula-
tions due to channel blockade. This blockade was partially reversible
on washout (data not shown). Compound 54 did not induce a sig-
nificant use dependent blockade.
In order to examine the effects of compounds 1, 53 and
54 on T-type calcium channels, a use dependent proto-
col was utilized as described in the biology section. In
the absence of compound, there was a 33.8ꢁ3.4%
decrease in current as a result of the protocol. This
decrease in current amplitude stabilized within 10 s
under control conditions. Upon application of com-
pound 1 or compound 53, a further decrease in current
was observed. In the presence of 200 mM and 1 mM of
compound 1, an additional 20.0ꢁ9.0% and 34.3ꢁ7.4%
decrease in current was observed by the last pulse in the
protocol respectively in comparison to control (Fig. 1).
This use dependent block could be partially removed
upon washout, with 84.1ꢁ4.0% of the blocked current
returning. In the presence of 200 mM and 1 mM of
compound 53, an additional 5.1ꢁ6.5% and 11.1ꢁ1.1%
decrease in current was observed by the last pulse in the
protocol respectively in comparison to control. How-
ever, compound 1 induced significantly more block at
both 200 mM and 1 mM in comparison to compound 53
(P=0.002 and P=0.01, respectively). Upon application
of 1mM of compound 54, no further decrease in current
amplitude was observed in comparison to control (Fig.
1). To examine tonic block, the first pulse recorded
during the use dependent protocol was compared in the
absence and in the presence of compound. At 1 mM
compounds 1, 53 and 54 decreased current amplitudes
by 44.2ꢁ2.7%, 61.1ꢁ8.2% and 43.5ꢁ3.5% respec-
tively and were not significantly different from each
other.
3. Discussion
The compounds presented here provide a first genera-
tion structure–activity relationship (SAR) of compound
1 analogues. Below we provide a brief summary of the
medicinal chemistry transformations. Analogue
7
represents other haloform saturation and analogue 11
introduces steric bulk into the hydroxy functionality.
Analogues 9 and 18 represent methylene inserted ana-
logues of compound 1 and begin to explore the steric
tolerance of the amide, hydroxy group, aromatic and
aliphatic binding regions. Analogue 10 does not contain
an alpha hydrogen (instead contains an alkyne func-
tionality), to determine if the trifluoromethyl group or
absence of the alpha hydrogen increases activity. Ana-
logue 12 and 13 represent homologous transformations
introducing charge into the amide region. Analogues
38–48 explore the electron donating and withdrawing
effects at the ortho, meta, and para positions of
the phenyl ring. Analogue 50 fluorinates the methylene
insertion of analogue 18. Compounds 53 and 54 are

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
985
methylated versions of compound 1 at the amide and
alcohol, respectively. Analogue 55 is a closed ring ana-
logue of the lead compound and allow us to evaluate
ring conformation and activity. Finally, analogue 58
introduces an additional phenyl ring fused to compound
1 to explore the steric bulk of the phenyl region.
tected at 4 h. Toxicity of wild running was only noted at
the 1 h time point in 2 out of the 4 animals. Compound
53 also noted protection in the MES model at 100 mg/
kg, with no toxicity reported at that dose. Interestingly,
this compound was also tested at the 4 and 6 h-intervals
in rats and it was found to protect 4/4 animals as both
time intervals in the MES model at 100 mg/kg, thus
noting its protection at later time points. There was also
no toxicity noted in any of the animals. Therefore, the
methylated alcohol and amide will represent new leads
from this class and will allow for future development.
Although already noted steric bulk is not tolerated in
the alcohol region. The closed ring analogue 55 pro-
tected 3/3 animals at 100 mg/kg in the MES model
where no protection was seen in the ScMET model, as
well as minimal toxicity noted (1/8 animals). Analogue
58 did not possess any anticonvulsant activity, thus dis-
playing the steric tolerance of compound 10s aromatic
region.
Tables 1 and 2 summarize Phase I rat and mouse antic-
onvulsant evaluation, respectively. Saturation of the
trifluoromethyl group with a chlorine (compound 7)
decreased activity and the only protection was noted at
100 mg/kg for 0.5 h. The methylene inserted analogues 9
and 18 showed reduced activity, indicating that the tri-
fluromethyl and phenyl regions do not tolerate a probe
depth greater than a methylene group in this region.
The alkyne substitution in compound 10 also reduced
activity and toxicity, therefore acknowledging the tri-
fluoromethyl group is responsible for activity, instead of
the absence of an alpha hydrogen. Obviously steric bulk
is not tolerated as seen by the protection of 1/3 animals
at 100 mg/kg in the MES model for compound 11. The
primary amine (compound 12) offered protection of all
3 animals at 100 mg/kg in the MES model but its dura-
tion of action was only 0.5 h. The acid 13 of the lead
compound did not protect any animals in either model
as well as in a 6 Hz mouse evaluation. Compounds in
the 6 Hz test are evaluated for their ability to block sei-
zures induced by a low frequency (6 Hz) long-duration
(3 s) stimulus delivered through corneal electrodes.12
Phase I rat data showed that several compounds were
selective for the two seizure models. As noted, complete
protection was noted for compound 1 in MES at 30 mg/
kg. No protection was noted for any of the compounds
in the ScMET model in the rats. Compounds 10 and 47
had increased activity at 2 and 4 h intervals, whereas 12
offered protection but only up to 2 h.
Patch clamp electrophysiology studies demonstrated
significant tonic blockade of T-type calcium current by
compounds 1, 53 and 54 at 1 mM. Furthermore, com-
pounds 1 and 53 induced a significant use dependent
blockade of T-type calcium currents. These results sug-
gest that the mechanism of anticonvulsant activity may
include blockade of T-type calcium currents.
The meta-substituted chlorine 38 provided protection
up to 4 h at 100 mg/kg but resulted in increased toxicity
and even death of the mice at 300 mg/kg. The para-
substituted chlorine 45 was inactive against both seizure
models, as well as the para-methoxy 41. The 3,4-
dichloro analogue 44 only protected at a dose of 300
mg/kg, where toxicity was also prevalent. The ortho-
and meta-substituted methoxy groups (compounds 39
and 40, respectively) offered little protection and activity
was only seen at 100 mg/kg in 1/3 animals in the MES
model for compound 39. The same pattern was noticed
for the methyl substituted analogues. The meta-fluoro
analogue 46 offered protection of all the animals at 100
mg/kg in both models and similar toxicity to compound
1 with the animals unable to grasp the rotorod. The
para-fluoro analogue 47 is selective against the ScMET
model protecting 5/5 animals at 100 mg/kg with a
duration of up to 4 h. Although, there was no separa-
tion between activity and toxicity noted. The meta-sub-
stituted trifluoromethyl 48 was found to protect at 100
mg/kg in the MES model in mice. In rats, it offered
protection in 4 of the 4 animals tested up to 4 h at 30
mg/kg, with no noted toxicity at that dosage. All toge-
ther, no substantial SAR was noted for the aromatic
substitutions.
4. Conclusion
A series of hydroxyamides were synthesized and sub-
mitted to the NINDS ADD Program for anticonvulsant
screening. We have demonstrated that compound 1 is
an active orally available anticonvulsant with similar
activity to phenytoin. Compounds 53 and 54, which are
the methylated alcohol and amide, showed similar
activity. However, compound 53 offered increased
duration of action (up to 6 h) with no observed toxicity.
This study provides evidence for the first time that the
anticonvulsant activity of these compounds may be due
to use dependent blockade of T-type calcium channels.
5. Experimental
5.1. Chemistry
Compound 50 showed protection against seizures in
both models. Phase I mouse data revealed that com-
pound 54 was similarily active to compound 1. Protec-
tion at 100 mg/kg was observed for 3/3 mice at 0.5 h in
the MES model and 1/1 mice were protected at the same
dose and time interval in the ScMET model. The rat
evaluation revealed that 4 out of 4 animals were pro-
All reactions requiring anhydrous conditions were per-
formed in flame-dried glassware under an atmosphere
of argon or nitrogen. Melting points were determined
with an Electrothermal Mel-Temp melting point appa-
1
ratus and are uncorrected. H and 13C NMR spectra
were measured on a General Electric 300 MHz or Var-
ian 300 or 500 MHz. Chemical shifts are reported in

986
H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
ppm relative to resonances of the solvent, CDCl3 (unless
1
concentrated to yield the crude a-hydroxyamide. Pur-
ification was performed on a flash column (1:1 hexanes–
EtOAc), collecting all fractions with a component of
Rf=0.28 to yield the pure a-hydroxyamide.
specified otherwise): 7.25 ppm (s) in the H spectra and
77.08 ppm (t) in the 13C spectra. 19F NMR spectra were
measured on a Varian 300 MHz instrument, externally
referenced with TFA (ꢂ76.6 ppm). IR spectra were
recorded on either a Perkin–Elmer 1310 or FT-IR
Impact 400D. High-resolution mass spectrometry was
performed at the University of Illinois at Urbana-
Champaign School of Chemical Science. Elemental
analyses were performed by Atlantic Microlabs. Con-
centration in vacuo refers to high vacuum (0.35 mmHg).
Concentration refers to a rotary evaporator with a
water aspirator. Anhydrous THF, diethyl ether, and di-
chloromethane were purified by pressure filtration
through activated alumina. Flash chromoatography was
performed on silica gel (Merck grade 9385, 230–400
mesh, 60 A). Hydrogen chloride gas was purchased
from Aldrich or produced by dropwise addition of sul-
furic acid to ammonium chloride.
5.1.4. 3,3,3-Trifluoro-2-hydroxy-2-phenyl-propionamide
(1).24 General Procedure C was employed with 2 (8.0 g,
40 mmol) and concd HCl (8.0 mL). The hydroxyamide
was obtained as a white solid (8.6 g, 99%): mp=83–
85 ꢀC. 1H NMR: d (CDCl3, 300 MHz) 7.65–7.68 (m,
2H), 7.41–7.46 (m, 3H), 6.17 (s, 2H), 4.78 (s, 1H). 13C
NMR: d (CD3OD, 125 MHz) 173.0, 136.5, 130.1, 129.2,
1
2
127.7, 125.5 (q, JCF=473 Hz), 79.4 (q, JCF=46 Hz).
19F NMR: d ꢂ73.14. IR (KBr): 3360, 1697 cmꢂ1. APCI
MS m/z: 219.9 (M+H+). HRMS (EI): calcd for
C9H8F3NO2, 219.0507; found, 219.0507. Anal. calcd for
C9H8F3NO2: C, 49.32; H, 3.68; N, 6.39. Found: C,
49.62; H, 3.63; N, 6.45.
5.1.5. 3,3,3-Trifluoro-2-hydroxy-2-phenyl-propionitrile
(2). 2,2,2-Trifluoro-1-phenyl-ethanone (7.0 g, 40.0
mmol) in a minimal amount of dry CH2Cl2 was cooled
to 0 ꢀC and TiCl4 (5.3 mL, 48.0 mmol) was added
dropwise. After 30 min, TMSCN (5.4 mL, 40.0 mmol)
was added. The mixture was brought to room temper-
ature and allowed to stir for 6 h. The reaction was quen-
ched with water (30 mL) and the organic layer was
washed with saturated NaHCO3 (30 mL), dried over
MgSO4, filtered, and concentrated to yield a colorless
5.1.1. General Procedure A: preparation of ketones from
2,2,2-trifluoro-1-piperidin-1-yl-ethanone. Crushed Mg
(1.4 equiv), 2-3 I2 crystals and a small portion of the
ketone was heated until the reaction began to occur.
The remaining ketone (1.2 equiv) in dry THF (25 mL)
was added dropwise over 30 min. The mixture was
refluxed for 2 h and then allowed to cool to room
temperature. The mixture was cooled to 0 ꢀC and 2,2,2-
Trifluoro-1-piperidin-1-yl-ethanone (19, 1.0 equiv) in
dry THF (5 mL) was added dropwise over 30 min. The
mixture was brought to room temperature and allowed
to stir for 2 h. The reaction was quenched with satu-
rated NH4Cl (5 mL), filtered, dried over MgSO4, fil-
tered, and concentrated to yield the crude product.
Purification was performed on a flash column (8:1 hex-
anes–EtOAc), collecting all fractions with a component
of Rf=0.38 to yield the pure ketone.
oil (8.0 g, 99%). IR (neat): 3389, 3071, 2358 cmꢂ1
.
5.1.6. 3-Chloro-3,3-difluoro-2-hydroxy-2-phenyl-propio-
nitrile (3). General Procedure B was employed with 2
chloro-2,2-difluoro-1-phenyl-ethanone (3.0 g, 15.7
mmol), TMSCN (3.1 g, 31.2 mmol), KCN (100 mg) and
18-crown-6 (100 mg). The cyanohydrin was obtained as
a yellow oil (3.3 g, 96%). IR (neat): 3383, 2246 cmꢂ1
.
5.1.2. General Procedure B: preparation of cyanohydrins
from ketones.14 The ketone (1.0 equiv) was dissolved in
a minimal amount of dry CH2Cl2. Trimethylsilyl cya-
nide (TMSCN, 2.2 equiv) and ZnI2 (1.0 equiv), (or
KCN and 18-crown-6, 10 mg each for every 1.0 mmole
of ketone) were added. The mixture was stirred at room
temperature overnight (16 h). The CH2Cl2 was evapo-
rated in vacuo and a minimal amount of dry THF was
added. The mixture was cooled to 0 ꢀC and 15% HCl (5
mL) was added and then stirred at room temperature
for 2 h. The solution was combined with H2O and
extracted with Et2O (3ꢃ25 mL), dried over MgSO4, fil-
tered, and concentrated to yield the cyanohydrin. The
cyanohydrins were used in General Procedure C with-
out further purification.
5.1.7. 2-Hydroxy-2-phenyl-propionitrile (4). General
Procedure B was employed with acetophenone (5.0 g,
41.6 mmol), TMSCN (12.2 mL, 91.6 mmol), KCN (400
mg) and 18-crown-6 (400 mg). The hydroxyamide was
obtained as a colorless oil (6.2 g, 100%). IR (neat):
3400, 2220 cmꢂ1
.
5.1.8. 2-Benzyl-3,3,3-trifluoro-2-hydroxy-propionitrile (5).
General Procedure B was employed with 1,1,1-tri-
fluoro-3-phenyl-propan-2-one (1.0 g, 5.3 mmol),
TMSCN (1.6 mL, 11.7 mmol), KCN (60 mg) and
18-crown-6 (60 mg). The cyanohydrin was obtained
as an orange oil (1.0 g, 91%). IR (neat): 3627, 2963,
2217 cmꢂ1
.
5.1.9. 2-Hydroxy-2-phenyl-but-3-yne nitrile (6).25 Gen-
eral Procedure B was employed with 1-phenyl-propy-
none (2.2 g, 16.9 mmol), TMSCN (3.3 g, 33.3 mmol),
KCN (80 mg) and 18-crown-6 (80 mg). The cyanohy-
drin was obtained as a dark brown oil (2.0 g, 75%). IR
5.1.3. General Procedure C: preparation of ꢀ-hydroxy-
amides from cyanohydrins. The cyanohydrin was dis-
solved in 1,4-dioxane (2 mL). The mixture was cooled to
0 ꢀC, and previously cooled concd HCl (0.2 mL for
every 1 mmole of cyanohydrin) was added. HCl gas was
then passed through the reaction mixture for 45 min at
0 ꢀC. The mixture was allowed to stand at room temp-
erature overnight (16 h). The mixture was extracted
with EtOAc (3ꢃ25 mL), dried over MgSO4, filtered, and
(neat): 3400, 2246 cmꢂ1
.
5.1.10. 3-Chloro-3,3-difluoro-2-hydroxy-2-phenyl-propio-
namide (7). General Procedure C was employed with 3
(3.3 g, 15.2 mmol) and concd HCl (3.0 mL). The

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
987
hydroxyamide was obtained as a white solid (1.8 g,
50%): mp 79–81 ꢀC. H NMR (CD3OD, 300 MHz) d
on a flash column (3:1 hexanes–EtOAc), collecting all
fractions with a component of Rf=0.35. The product
was recrystallized from hot toluene to yield a white solid
(605 mg, 68%): mp 70–72ꢀC. 1H NMR: d (CDCl3,
300 MHz) 7.64–7.34 (m, 10H), 6.68 (d, 2H), 4.61 (m,
2H). 13C NMR: d (CD3OD, 125 MHz) 169.4, 136.7,
132.4, 129.7, 129.0, 128.9, 128.7, 128.2, 127.7, 126.7,
125.4 (q, JCF=287 Hz), 109.3, 85.5 (q, JCF=26 Hz),
69.3. 19F: d ꢂ67.92. IR (KBr): 3227, 1700 cmꢂ1. ESI MS
m/z: 308.5 (M-Hꢂ). HRMS (EI): calcd for
C16H14F3NO2, 309.0977; found, 309.0979. Anal. calcd
for C16H14F3NO2: C, 62.13; H, 4.56; N, 4.53. Found: C,
62.20; H, 4.63; N, 4.59.
1
7.31–7.76 (m, 5H). 13C NMR (CD3OD, 125 MHz)
d 173.0, 136.4, 134.7, 134.7, 130.7, 130.0, 129.0, 127.8,
1
2
126.7 (q, JCF=450 Hz), 82.4 (q, JCF=50 Hz). IR
(KBr): 3510, 3340, 3224, 1700 cmꢂ1. APCI MS m/z:
236.0 (M+H+). HRMS (EI): calcd for C9H8ClF2NO2,
235.0212; found, 235.0214. Anal. calcd for
C9H8ClF2NO2: C, 45.88; H, 3.42; N, 5.94. Found: C,
45.88; H, 3.44; N, 6.01.
1
2
5.1.11. 2-Hydroxy-2-phenyl-propionamide (8).26 General
Procedure C was employed with 4 (850 mg, 5.8 mmol)
and conc HCl (2.0 mL). The hydroxyamide was
obtained as a white solid (290 mg, 30%): mp 97–99 ꢀC.
1H NMR: d (CDCl3, 300 MHz) 7.10–7.71 (m, 5H), 6.61
(d, J=7.7 Hz, 2H), 2.15 (s, 1H). 13C NMR: d (CDCl3,
75 MHz) 173.7, 141.3, 129.9, 128.5, 128.4, 72.0, 29.8. IR
(KBr): 3371, 3193, 1733 cmꢂ1. APCI MS m/z: 148.1,
loss of H2O, (M+H+).
5.1.15.
3-Amino-1,1,1-trifluoro-2-phenyl-propan-2-ol
(12).16 Compound 2 (2.0 g, 10.0 mmol) was dissolved
in dry Et2O (5 mL) and added to cold (0 ꢀC) LiAlH4 (0.4
g, 10.9 mmol) dissolved in dry Et2O (10 mL). The reac-
tion mixture was stirred at room temperature for 2 h,
then cooled to 0 ꢀC. After allowing the reaction mixture
to warm to room temperature, H2O (2.0 mL) and 15%
NaOH (1.0 mL) were added dropwise. The precipitate
was filtered, washed with Et2O, and concentrated. Pur-
ification was performed on a flash column (3:2 hexanes–
EtOAc), collecting all fractions with a component of
Rf=0.14. The product was recrystallized from 1:1 hex-
anes–EtOAc to yield a white solid (1.6 g, 78%): mp 57–
59 ꢀC. 1H NMR: d (CDCl3, 500 MHz) 7.60–7.38 (m,
5H), 3.52 (d, J=13.2 Hz, 1H), 3.04 (d, J=13.5 Hz, 1H).
13C NMR: d (CDCl3, 125 MHz) 36.9, 128.4, 128.3,
5.1.12. 2-Benzyl-3,3,3-trifluoro-2-hydroxy-propionamide
(9). General Procedure C was employed with 5 (1.0 g,
4.8 mmol) and concd HCl (1.0 mL). The hydroxyamide
wasꢀobtained as a white solid (1.0 g, 89%): mp=115–
1
116 C. H NMR: d (CDCl3, 300 MHz) 7.25–7.34 (m,
5H), 6.02 (d, J=171.3, 2H), 3.59 (s, 1H), 3.36 (d,
J=13.8 Hz, 1H), 2.94 (d, J=13.5 Hz, 1H). 13C NMR: d
(CD3OD, 125 MHz) 171.4, 134.5, 131.2, 128.5, 128.2,
1
127.6, 127.4, 127.3, 125.9 (q, JCF=285 Hz), 123.5,
110.3, 79.4 (q, 2JCF=27 Hz), 38.4; 19F NMR: d ꢂ76.60.
IR (KBr): 3503, 3385, 3210, 1700 cmꢂ1. ESI MS m/z:
232.2 (MꢂHꢂ). HRMS (EI): calcd for C10H10F3NO2,
233.0664; found, 233.0665. Anal. calcd for
C10H10F3NO2: C, 51.51; H, 4.32; N, 6.01. Found: C,
51.27; H, 4.36; N, 5.99.
126.2, 125.7 (q, JCF=284 Hz), 74.5 (q, JCF=27 Hz),
1
2
45.4;. 19F NMR: d ꢂ77.52. IR (KBr): 2973, 3349 cmꢂ1
.
APCI MS m/z: 206.1 (M+H+). HRMS (EI): calcd for
C9H10F3NO, 206.0793; found, 206.0789. Anal. calcd
for C9H10F3NO: C, 52.68; H, 4.91; N, 6.83. Found: C,
52.87; H, 5.02; N, 6.78.
5.1.13. 2-Hydroxy-2-phenyl-but-3-ynoic acid amide (10).
General Procedure C was employed with 6 (2.0 g, 12.7
mmol) and concd HCl (2.5 mL). The hydroxyamide was
obtained as a white solid (0.7 g, 31%): mp 79–81 ꢀC. 1H
NMR: d (CDCl3, 300 MHz) 7.70–7.35 (m, 5H), 6.07 (d,
2H), 4.60 (s, 1H), 2.81 (s, 1H). 13C NMR: d (CDCl3,
75 MHz) 173.7, 140.1, 129.5, 129.2, 126.4, 82.8, 76.3,
73.6. IR (KBr): 3453, 3409, 3274, 3170, 2100, 1696
cmꢂ1. CI MS m/z: 175.15 (MꢂHꢂ). HRMS (FAB
M+H+): calcd for C10H10NO2, 176.1919; found
176.0718. HPLC mBondapak C18 column (A: 0.1%
TFA in H2O, B: 0.1% TFA in 1:1 CH3CN:H2O, B
increased from 5 to 10% over 30 min, one peak at 10.54
mins.) (B: 0.1% TFA in H2O, B: 0.1% TFA in MeOH,
B increased from 5 to 10% over 30 mins, one peak at
2.79 mins.)
5.1.16. 3,3,3-Trifluoro-2-hydroxy-2-phenyl-propionic acid
(13). Compound 1 (1.0 g, 4.6 mmol) was dissolved in
1,4-dioxane (1.5 mL). Conc. HCl (2.5 mL) was added to
the reaction mixture dropwise at 0 ꢀC. The mixture was
heated at 100 ꢀC for 24 h. After cooling, the solution
was washed with H2O (4ꢃ20 mL) and concentrated.
Purification was performed on a flash column (1:1 hex-
anes–EtOAc), collecting all fractions with a component
of Rf=0.20 to yield a white solid (700 mg, 70%): mp
96–97 ꢀC. H NMR: d (CD3OD, 300 MHz) 7.69–7.32
1
(m, 5H). 13C NMR: d (CD3OD, 75 MHz) 170.2, 134.9,
129.7, 129.3, 128.3, 126.8, 126.0, 122.3 (q, JCF=465
1
2
Hz), 109.9, 78.4 (q, JCF=45 Hz). 19F NMR: d ꢂ75.45.
IR (KBr): 3403, 1735 cmꢂ1. EI MS m/z: 220.0. HRMS
(EI): calcd for C9H7F3O3, 220.0344; found, 220.0343.
Anal. calcd for C9H7F3O3: C, 49.10; H, 3.20. Found: C,
48.99; H, 3.21.
5.1.14. 2-Benzyloxy-3,3,3-trifluoro-2-phenyl-propiona-
mide (11).27 Compound 1 (0.63 g, 2.9 mmol) was dis-
solved in dry CH2Cl2 (14 mL) and 5% NaOH (7 mL)
was added. Benzyl bromide (0.5 g, 2.9 mmol) was added
and the mixture was allowed to stir for 10 min. Bu4NBr
(0.1 g, 0.3 mmol) was added to the reaction mixture and
stirred for 16 h at room temperature. The organic layer
was washed with H2O (3ꢃ10 mL), dried over Na2SO4,
filtered, and concentrated. Purification was performed
5.1.17. N0-Benzylidene-N,N-dimethyl-hydrazine (14).28
Benzaldehyde (0.5 g, 4.7 mmol) and ethanol (24 mL)
were cooled to 10 ꢀC and a solution containing N,N-
dimethylhydrazine (0.54 mL, 7.1 mmol) and ethanol (5
mL) were added dropwise. The resulting mixture was
allowed to warm to room temperature, followed by
stirring for 30 min, and then heated to reflux for 24 h.
After cooling, the reaction mixture was concentrated in

988
H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
vacuo and the resulting mixture diluted with H2O and
extracted with Et2O (3ꢃ20 mL). The organic layer was
washed with brine, dried over Na2SO4, filtered, and
The ether layer was concentrated and distilled in vacuo
(53 ꢀC, 2.6 torr) to obtain a colorless oil (18.0 g, 95%).
1H NMR: d (CDCl3, 500 MHz) 3.20 (d, J=17.7 Hz,
4H), 1.26 (m, 5H). 13C NMR: d (CDCl3, 125 MHz)
155.0 (q, 2JCF=35.0 Hz), 116.9 (q, 1JCF=286 Hz), 46.7,
44.4, 26.3, 25.4, 24.0. 19F NMR: d ꢂ68.02. IR (neat):
2946, 2864, 1695 cmꢂ1. APCI MS m/z: 182.2 (M+H+).
1
concentrated to yield a colorless oil (636 mg, 91%). H
NMR: d (CDCl3, 300 MHz) 7.16–7.86 (m, 5H), 3.02 (s,
6H). 13C NMR: d (CDCl3, 75 MHz) 137.6, 133.2, 129.1,
128.8, 127.9, 126.2, 43.4. The product was used without
further purification.
5.1.23. 1-(3-Chloro-phenyl)-2,2,2-trifluoro-ethanone (20).
General Procedure A was employed with magnesium
(0.75 g, 31 mmol), 1-bromo-3-chloro-benzene (3.1 mL,
27 mmol), and 19 (4.0 g, 22 mmol) in dry THF (25 mL).
The ketone was obtained as a colorless oil (2.65 g, 58%)
purified by vacuum distillation (74 ꢀC, 15 torr). 1H
NMR: d (CDCl3, 300 MHz) 7.96 (s, 1H), 7.90 (d, J=6.9
Hz, 1H), 7.62 (d, J=6.9 Hz, 1H), 7.46 (t, J=7.3 Hz,
5.1.18.
Methyl-(3,3,3-trifluoro-1-phenyl-propenyl)-dia-
zene (15). To a solution of 14 (2.0 g, 13.5 mmol) in
pyridine (40 mL) at 0 ꢀC was added trifluoroacetic
anhydride (18 mL, 130 mmol) dropwise with stirring.
After stirring for 5 h at room temperature, the solution
was concentrated in vacuo and CH2Cl2 was added to
the residue. The mixture was washed with 1 N HCl (100
mL), H2O (100 mL) and saturated Na2CO3 (100 mL).
The organic layer was dried over MgSO4, filtered, and
concentrated to yield a colorless oil (2.1 g, 76%). The
product was used without further purification. All
spectral data matched the literature.17
2
1H). 13C NMR: d (CDCl3, 75 MHz) 179.8 (q, JCF=36
Hz), 136.0, 135.8, 131.8, 130.8, 130.2, 128.5, 116.9 (q,
1JCF=289 Hz). IR (neat): 3074, 1726 cmꢂ1. EI MS m/z:
206.1.
5.1.24.
2,2,2-Trifluoro-1-(2-methoxy-phenyl)-ethanone
5.1.19. Preparation of 3,3,3-trifluoro-1-phenyl-propan-1-
one (16). A solution of 15 (2.1 g, 9.8 mmol) in CH3CN
(20 mL) and 6N HCl (20 mL) was allowed to stir for 24
h at room temperature. The mixture was concentrated
in vacuo, extracted with CH2Cl2 (4ꢃ20 mL), dried over
Na2SO4, filtered, and concentrated to yield an oil (450
(21). General Procedure A was employed with magne-
sium (0.7 g, 29 mmol), 1-bromo-2-methoxy-benzene (3.1
mL, 25 mmol), and 19 (3.8 g, 21 mmol) in dry THF (30
mL). The ketone was obtained as a colorless oil (2.5 g,
58%). 1H NMR: d (CDCl3, 300 MHz) 7.53–7.65 (m,
2H), 6.99–7.04 (m, 2H), 3.87 (s, 3H). 13C NMR: d
1
2
mg, 13%). H NMR: d (CDCl3, 300 MHz) 8.05–7.20
(CDCl3, 75 MHz) 183.5 (q, JCF=36.8 Hz), 160.3,
(m, 5H), 3.79 (q, J=9.9 Hz, 2H). 13C NMR: d (CDCl3,
75 MHz) 190.2, 136.3, 134.7, 129.4, 128.8, 124.6 (q,
1JCF=274 Hz), 42.6 (q, 2JCF=28.2 Hz). IR (neat): 3200,
136.4, 131.7, 122.2, 121.2, 116.7 (q, JCF=289.2 Hz),
112.6, 56.2. IR (neat): 2949, 2845, 1713 cmꢂ1. APCI MS
1
m/z: 205.1 (M+H+).
1700 cmꢂ1
.
5.1.25.
2,2,2-Trifluoro-1-(3-methoxy-phenyl)-ethanone
5.1.20. 4,4,4-Trifluoro-2-hydroxy-2-phenyl-butyronitrile
(17). General Procedure B was employed with 16 (1.5
g, 8.0 mmol), TMSCN (2.3 mL, 17.6 mmol), KCN (80
mg) and 18-crown-6 (80 mg). The cyanohydrin was
obtained as a brown oil (1.8 g, 97%). IR (neat): 3403,
(22). General Procedure A was employed with magne-
sium (0.7 g, 29 mmol), 1-bromo-3-methoxy-benzene (3.2
mL, 25 mmol), and 19 (3.8 g, 21 mmol) in dry THF (25
mL). The ketone was obtained as a colorless oil (2.8 g,
66%) purified by vacuum distillation (93 ꢀC, 15 torr).
1H NMR: d (CDCl3, 300 MHz) 7.17–7.56 (m, 4H), 3.78
(s, 3H). 13C NMR: d (CDCl3, 75 MHz) 180.6 (q,
2JCF=34.7 Hz), 160.5, 131.5, 130.4, 122.9, 122.3, 117.2
2248 cmꢂ1
.
5.1.21.
4,4,4-Trifluoro-2-hydroxy-2-phenyl-butyramide
1
(18). General Procedure C was employed with 17 (1.8
g, 8.4 mmol) and concd HCl (2.5 mL). The hydroxy-
amide was obtained as white solid (1.6 g, 82%): mp 75–
76 ꢀC. 1H NMR: d (CDCl3, 300 MHz) 7.48–7.33 (m,
5H), 6.77 (s, 1H), 5.62 (s, 1H), 4.02 (bs, 1H), 3.30 (m,
1H), 2.70 (m, 1H). 13C NMR: d (CD3OD, 125 MHz)
(q, JCF=289.2 Hz), 114.5, 55.5. IR (neat): 3012, 2947,
2841, 1721 cmꢂ1. EI MS m/z: 204.1.
5.1.26.
2,2,2-Trifluoro-1-(4-methoxy-phenyl)-ethanone
(23). General Procedure A was employed with magne-
sium (0.7 g, 29 mmol), 1-bromo-4-methoxy-benzene (3.1
mL, 25 mmol) and 19 (3.8 g, 21 mmol) in dry THF (25
mL). The ketone was obtained as a colorless oil (3.4 g,
81%). 1H NMR: d (CDCl3, 300 MHz) 8.03–8.06 (m,
2H), 6.97–7.02 (m, 2H), 3.90 (s, 3H). 13C NMR: d
1
174.9, 140.8, 128.6, 128.4, 124.7, 123.6 (q, JCF=370
2
Hz), 109.3, 41.8 (q, JCF=26 Hz). 19F NMR: d ꢂ59.12.
IR (KBr): 3426, 1675 cmꢂ1. ESI MS m/z: 232.3 (MꢂHꢂ).
HRMS (EI): calcd for C10H10F3NO2, 233.0664; found,
233.0665. Anal. calcd for C10H10F3NO2: C, 51.51; H,
4.32; N, 6.01. Found: C, 51.62; H, 4.27; N, 6.03.
2
(CDCl3, 75 MHz) 179.4 (q, JCF=34.7 Hz), 165.9,
1
133.2, 128.2, 123.3, 117.4 (q, JCF=289.2 Hz), 114.9,
114.7, 56.2. IR (neat): 3392, 2941, 2845, 1707 cmꢂ1
.
5.1.22. 2,2,2-Trifluoro-1-piperidin-1-yl-ethanone (19).18
Trifluoroacetic anhydride (14.8 mL, 105 mmol) was
added via an additional funnel over 3 h to triethylamine
(14.6 mL, 105 mmol), piperdine (12.5 mL, 126 mmol)
and ethyl ether (6 mL). The mixture was cooled to 0 ꢀC
and allowed to stir for 30 min. The mixture was brought
to room temperature and allowed to stir vigorously for
1 h. The mixture was washed with 1M HCl (20 mL).
APCI MS m/z: 205.1 (M+H+).
5.1.27. 2,2,2-Trifluoro-1-m-tolyl-ethanone (24). General
Procedure A was employed with magnesium (0.75 g, 31
mmol), 1-bromo-3-methyl-benzene (3.2 mL, 26.5 mmol)
and 19 (3.5 g, 19.3 mmol) in dry THF (25 mL). The
ketone was obtained as a yellow oil (2.3 g, 63%), pur-
ified by vacuum distillation (75–77 ꢀC, 15 torr). 1H

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
989
NMR: d (CDCl3, 300 MHz) 7.81 (s, 2H), 7.32–7.44 (m,
2H), 2.36 (s, 3H). 13C NMR: d (CDCl3, 75 MHz) 180.2
(q, JCF=30.3 Hz), 139.0, 136.0, 130.1, 129.8, 128.7,
127.0, 116.8 (q, JCF=290.1 Hz), 20.5. IR (neat): 2929,
1719 cmꢂ1. EI MS m/z: 188.1.
was obtained as a yellow oil (2.2 g, 96%). IR (neat):
3386, 2981, 2883, 2246 cmꢂ1
.
2
1
5.1.35. 3,3,3-Trifluoro-2-hydroxy-2-p-tolyl-propionitrile
(32). General Procedure B was employed with 25 (2.2
g, 11.7 mmol), TMSCN (3.4 mL, 25.7 mmol), KCN
(120 mg) and 18-crown-6 (120 mg). The cyanohydrin
was obtained as a yellow oil (2.5 g, 100%). IR (neat):
5.1.28. 2,2,2-Trifluoro-1-p-tolyl-ethanone (25). General
Procedure A was employed with magnesium (0.75 g, 31
mmol), 1-bromo-4-methyl-benzene (3.3 mL, 26.5 mmol)
and 19 (4.0 g, 22 mmol) in dry THF (30 mL). The
ketone was obtained as a yellow oil (2.9 g, 71%), pur-
ified by vacuum distillation (70–71 ꢀC, 15 torr). 1H
NMR: d (CDCl3, 300 MHz) 7.87 (t, J=6.5 Hz, 2H),
7.22 (t, J=7.3 Hz, 2H), 2.36 (s, 3H). 13C NMR: d
3407, 3037, 2964, 2928, 2246 cmꢂ1
.
5.1.36. 2-(3,4-Dichloro-phenyl)-3,3,3-trifluoro-2-hydroxy-
propionitrile (33). General Procedure B was employed
with 26 (2.0 g, 8.2 mmol), TMSCN (2.4 mL, 18.1
mmol), KCN (90 mg) and 18-crown-6 (90 mg). The
cyanohydrin was obtained as a orange oil (2.1 g, 95%).
2
(CDCl3, 75 MHz) 180.2 (q, JCF=31.4 Hz), 147.5,
1
130.4, 130.1, 127.8, 117.3 (q, JCF=290.3 Hz), 21.6. IR
(neat): 2927, 1716 cmꢂ1
(M+H+).
IR (neat): 3378, 3099, 2982, 2883, 2247 cmꢂ1
.
. APCI MS m/z: 189.0
5.1.37. 2-(4-Chloro-phenyl)-3,3,3-trifluoro-2-hydroxy-
propionitrile (34). General Procedure B was employed
with 1-(4-chloro-phenyl)-2,2,2-trifluoro-ethanone (3.0 g,
14.4 mmol), TMSCN (4.2 mL, 32 mmol), KCN (140
mg) and 18-crown-6 (140 mg). The cyanohydrin was
obtained as a dark oil (3.4 g, 100%). IR (neat): 3383,
5.1.29. 1-(3,4-Dichloro-phenyl)-2,2,2-trifluoro-ethanone
(26). General Procedure A was employed with magne-
sium (0.75 g, 31 mmol), 4-bromo-1,2-dichloro-benzene
(3.4 mL, 26.5 mmol) and 19 (4.0 g, 22 mmol) in dry
THF (30 mL). The ketone was obtained as a orange oil
2884, 2216 cmꢂ1
.
1
(3.84 g, 72%). H NMR: d (CDCl3, 300 MHz) 7.98 (s,
1H), 7.79 (dd, J=1.2 Hz, J=7.3 Hz, 1H), 7.53 (d,
5.1.38. 3,3,3-Trifluoro-2-(3-fluoro-phenyl)-2-hydroxy-
J=8.5 Hz, 1H). 13C NMR: d (CDCl3, 75 MHz) 178.7
(q, JCF=35.8 Hz), 140.9, 134.4, 131.9, 131.5, 129.7,
propionitrile (35). General Procedure B was employed
with 2,2,2-trifluoro-1-(3-fluoro-phenyl)-ethanone (650
mg, 3.4 mmol), TMSCN (0.5 mL, 4.1 mmol), KCN (30
mg) and 18-crown-6 (30 mg). The cyanohydrin was
obtained as a dark oil (0.74 g, 100%). IR (neat): 3383,
2
1
129.1, 116.7 (q, JCF=289.2 Hz). IR (neat): 3098, 2769,
1725 cmꢂ1. EI MS m/z: 242.0.
5.1.30.
2-(3-Chloro-phenyl)-3,3,3-trifluoro-2-hydroxy-
3087, 2981, 2884, 2247, 2884 cmꢂ1
.
propionitrile (27). General Procedure B was employed
with 20 (1.1 g, 5.3 mmol), TMSCN (1.6 mL, 11.6
mmol), KCN (60 mg) and 18-crown-6 (60 mg). The
cyanohydrin was obtained as a brown oil (1.25 g,
5.1.39. 3,3,3-Trifluoro-2-(4-fluoro-phenyl)-2-hydroxy-
propionitrile (36). General Procedure B was employed
with 2,2,2-trifluoro-1-(4-fluoro-phenyl)-ethanone (3.0 g,
15.6 mmol), TMSCN (4.6 mL, 34.3 mmol), KCN (160
mg) and 18-crown-6 (160 mg). The cyanohydrin was
obtained as a yellow oil (3.2 g, 94%). IR (neat): 3379,
100%). IR (neat): 3398, 3075, 2964, 2247 cmꢂ1
.
5.1.31. 3,3,3-Trifluoro-2-hydroxy-2-(2-methoxy-phenyl)-
propionitrile (28). General Procedure B was employed
with 21 (2.5 g, 12.2 mmol), TMSCN (3.6 mL, 27 mmol),
KCN (120 mg) and 18-crown-6 (120 mg). The cyano-
hydrin was obtained as a brown oil (2.70 g, 95%). IR
3124, 2968, 2882, 2247 cmꢂ1
.
5.1.40. 3,3,3-Trifluoro-2-hydroxy-2-(3-trifluoromethyl-
phenyl)-propionitrile (37). General Procedure B was
employed with 2,2,2-trifluoro-1-(3-trifluoromethyl-
phenyl)-ethanone (1.0 g, 4.1 mmol), TMSCN (1.2 mL,
9.1 mmol), KCN (50 mg) and 18-crown-6 (50 mg). The
cyanohydrin was obtained as a yellow oil (1.11 g,
(neat): 3379, 3082, 2964, 2843, 2244 cmꢂ1
.
5.1.32. 3,3,3-Trifluoro-2-hydroxy-2-(3-methoxy-phenyl)-
propionitrile (29). General Procedure B was employed
with 22 (2.8 g, 13.7 mmol), TMSCN (4.0 mL, 30.2
mmol), KCN (140 mg) and 18-crown-6 (140 mg). The
cyanohydrin was obtained as a brown oil (2.75 g, 87%).
100%). IR (neat): 3389, 2967, 2248 cmꢂ1
.
5.1.41. 2-(3-Chloro-phenyl)-3,3,3-trifluoro-2-hydroxy-
IR (neat): 3377, 2965, 2840, 2219 cmꢂ1
.
propionamide (38). General Procedure C was employed
with 27 (1.25 g, 5.3 mmol) and concd HCl (1.0 mL). The
hydroxyamide was obtained as a white solid (1.30 g,
5.1.33. 3,3,3-Trifluoro-2-hydroxy-2-(4-methoxy-phenyl)-
propionitrile (30). General Procedure B was employed
with 23 (3.4 g, 16.7 mmol), TMSCN (4.9 mL, 36.6
mmol), KCN (170 mg) and 18-crown-6 (170 mg). The
cyanohydrin was obtained as a brown oil (3.70 g, 96%).
97%): mp=61–64 ꢀC. H NMR: d (CDCl3, 300 MHz)
1
7.68 (s, 1H), 7.57 (d, J=6.9 Hz, 1H), 7.36–7.40 (m, 2H),
6.32 (d, J=19.6 Hz, 2H) 4.90 (s, 1H). 13C NMR: d
(CD3OD, 125 MHz) 169.4, 136.3, 135.5, 130.7, 130.5,
127.2, 125.8, 125.2 (q, 1JCF=282 Hz), 125.0, 122.0, 79.1
IR (neat): 3402, 2966, 2842, 2245 cmꢂ1
.
2
(q, JCF=27 Hz). 19F NMR: d ꢂ73.33. IR (KBr): 3385,
5.1.34. 3,3,3-Trifluoro-2-hydroxy-2-m-tolyl-propionitrile
(31). General Procedure B was employed with 24 (2.0
g, 10.6 mmol), TMSCN (3.2 mL, 23.3 mmol), KCN
(110 mg) and 18-crown-6 (110 mg). The cyanohydrin
1676 cmꢂ1. APCI MS m/z: 236.1 (M-OH). HRMS (EI):
calcd for C9H7ClF3NO2, 253.0117; found, 253.0123.
Anal. calcd for C9H7ClF3NO2: C, 42.62; H, 2.78; N,
5.52. Found: C, 42.70; H, 2.71; N, 5.57.

990
H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
mp=102–104 ꢀC. H NMR: d (CDCl3, 300 MHz) 7.54
(d, J=7.7 Hz, 2H), 7.24 (d, J=8.1 Hz, 2H), 6.05 (d,
J=29.3 Hz, 2H), 4.68 (s, 1H), 2.37 (s, 3H). 13C NMR: d
(CD3OD, 125 MHz) 170.0, 139.4, 134.5, 130.9, 129.3,
127.4, 125.5 (q, 1JCF=284 Hz), 123.6, 79.4 (q, 2JCF=27
Hz), 22.0. 19F NMR: d ꢂ73.25. IR (KBr): 3275, 1683
cmꢂ1. APCI MS m/z: 216.1 (M-OH). HRMS (EI): calcd
for C10H10F3NO2, 233.0664; found, 233.0668. Anal.
calcd for C10H10F3NO2: C, 51.51; H, 4.32; N, 6.01.
Found: C, 51.62; H, 4.24; N, 6.10.
1
5.1.42. 3,3,3-Trifluoro-2-hydroxy-2-(2-methoxy-phenyl)-
propionamide (39). General Procedure C was employed
with 28 (1.5 g, 6.5 mmol) and concd HCl (3.0 mL). The
hydroxyamide was obtained as a white solid (1.25 g,
78%): mp=101–102 ꢀC. 1H NMR: d (CDCl3, 300 MHz)
7.77 (d, J=7.8 Hz, 1H), 7.37–7.44 (m, 1H), 6.99–7.06
(m, 2H), 6.67 (s, 1H), 6.34 (s, 1H), 6.03 (s, 1H), 3.92 (s,
3H). 13C NMR: d (CD3OD, 125 MHz) 172.5, 158.6,
1
130.9, 128.7, 126.6, 125.7 (q, JCF=287 Hz), 124.1,
2
19
122.8, 120.6, 112.8, 79.4 (q, JCF=22 Hz), 55.2.
F
.
NMR: d ꢂ74.22. IR (KBr): 3342, 2359, 1700 cmꢂ1
APCI MS m/z: 249.9 (M+H+). HRMS (EI): calcd for
C10H10F3NO3, 249.0613; found, 249.0608. Anal. calcd
for C10H10F3NO3: C, 48.20; H, 4.04; N, 5.62. Found: C,
48.47; H, 4.13; N, 5.47.
5.1.47. 2-(3,4-Dichloro-phenyl)-3,3,3-trifluoro-2-hydroxy-
propionamide (44). General Procedure C was employed
with 33 (2.1 g, 7.8 mmol) and concd HCl (1.6 mL). The
hydroxyamide was obtained as a white solid (2.0 g,
89%): mp=105–106 ꢀC. 1H NMR: d (CDCl3, 300 MHz)
7.78 (s, 1H), 7.50 (d, J=2.1 Hz, 2H), 6.01 (d, J=81.6
Hz, 2H), 4.65 (s, 1H). 13C NMR: d (CD3OD, 125 MHz)
168.3, 133.9, 130.8, 128.6, 125.7, 125.1,125.0 (q,
1JCF=271 Hz), 121.3, 78.5 (q, 2JCF=27 Hz). 19F NMR:
d ꢂ73.46. IR (KBr): 3331, 2963, 1717 cmꢂ1. APCI MS
m/z: 270.1 (M-OH). HRMS (EI): calcd for
C9H6Cl2F3NO2, 286.9728; found, 286.9731. Anal. calcd
for C9H6Cl2F3NO2: C, 37.53; H, 2.10; N, 4.86. Found:
C, 37.77; H, 2.10; N, 4.81.
5.1.43. 3,3,3-Trifluoro-2-hydroxy-2-(3-methoxy-phenyl)-
propionamide (40). General Procedure C was employed
with 29 (2.0 g, 8.7 mmol) and concd HCl (2.8 mL). The
hydroxyamide was obtained as a white solid (1.60 g,
75%): mp=148–149 ꢀC. 1H NMR: d (CDCl3, 300 MHz)
7.22–7.38 (m, 3H), 6.94–6.98 (m, 1H), 5.92 (d, J=98
Hz, 2H), 4.74 (s, 1H), 3.83 (s, 3H). 13C NMR: d
(CD3OD, 125 MHz), 171.9, 160.0, 136.9, 129.2, 126.4,
125.4 (q, 1JCF=284 Hz), 122.6, 118.9, 114.5, 112.7, 79.3
2
(q, JCF=27 Hz), 54.8. 19F NMR: d ꢂ73.12. IR (KBr):
3440, 1690 cmꢂ1. APCI MS m/z: 248.4 (MꢂH+).
HRMS (EI): calcd for C10H10F3NO3, 249.0613; found,
249.0614. Anal. calcd for C10H10F3NO3: C, 48.20; H,
4.04; N, 5.62. Found: C, 48.05; H, 4.10; N, 5.61.
5.1.48.
2-(4-Chloro-phenyl)-3,3,3-trifluoro-2-hydroxy-
propionamide (45). General Procedure C was employed
with 34 (3.4 g, 14.4 mmol) and concd HCl (5.2 mL). The
hydroxyamide was obtained as a white solid (3.4 g,
93%): mp=65–68 ꢀC. H NMR: d (CDCl3, 300 MHz)
1
5.1.44. 3,3,3-Trifluoro-2-hydroxy-2-(4-methoxy-phenyl)-
propionamide (41). General Procedure C was employed
with 30 (1.0 g, 4.3 mmol) and concd HCl (3.5 mL). The
hydroxyamide was obtained as a white solid (1.10 g,
7.60 (d, J=8.1 Hz, 2H), 7.39 (d, J=8.5 Hz, 2H), 6.35
(d, J=27.7 Hz, 2H), 4.88 (s, 1H). 13C NMR: d
(CD3OD, 125 MHz) 172.6, 136.2, 135.2, 129.5, 129.3,
129.2, 125.3 (q, JCF=285 Hz), 79.0 (q, JCF=27 Hz).
19F NMR: ꢂ73.40. IR (KBr): 3457, 1654 cmꢂ1. APCI
MS m/z: 253.9 (M+H+). HRMS (EI): calcd for
C9H7ClF3NO2, 253.0117; found, 253.0119. Anal. calcd
for: C9H7ClF3NO2: C, 42.62; H, 2.78; N, 5.52. Found:
C, 42.57; H, 2.64; N, 5.60.
1
2
ꢀ
1
99%): mp=77–79 C. H NMR: d (CDCl3, 300 MHz)
7.59 (d, J=8.0 Hz, 2H), 6.87 (d, J=8.5 Hz, 2H), 4.79 (s,
1H), 3.73 (s, 3H). 13C NMR: d (CD3OD, 125 MHz)
1
172.3, 160.7, 128.1, 127.4, 126.5, 125.6 (q, JCF=285
Hz), 122.6, 113.6, 79.2 (q, 2JCF=29 Hz), 54.8. IR (KBr):
3446, 1684 cmꢂ1. APCI MS m/z: 248.0 (MꢂH+).
HRMS (EI): calcd for C10H10F3NO3, 249.0613; found,
249.0615. Anal. calcd for C10H10F3NO3: C, 48.20; H,
4.04; N, 5.62. Found: C, 48.20; H, 4.12; N, 5.56.
5.1.49.
3,3,3-Trifluoro-2-(3-fluoro-phenyl)-2-hydroxy-
propionamide (46). General Procedure C was employed
with 35 (740 mg, 3.4 mmol) and concd HCl (1.5 mL).
The hydroxyamide was obtained as a white solid (0.85
g, 98%): mp=101–103 ꢀC. 1H NMR: d (CDCl3,
300 MHz) 7.11–7.48 (m, 4H), 6.06 (d, J=49 Hz, 2H),
4.75 (s, 1H). 13C NMR: d (CD3OD, 75 MHz) 170.1,
5.1.45. 3,3,3-Trifluoro-2-hydroxy-2-m-tolyl-propionamide
(42). General Procedure C was employed with 31 (2.2 g,
10.2 mmol) and concd HCl (2.0 mL). The hydro-
xyamide was obtained as a white solid (2.25 g, 94%):
1
4
162.7 (d, JCF=242 Hz), 138.8 (d, JCF=6.4 Hz), 131.0
mp=71–74 ꢀC. H NMR: d (CDCl3, 300 MHz) 7.22–
(d, JCF=7.6 Hz), 124.9, (q, JCF=285 Hz), 123.5,
116.7 (d, 2JCF=20.5 Hz), 114.4 (d, 2JCF=23.8 Hz), 78.1
1
3
1
7.46 (m, 4H), 6.16 (s, 2H), 4.76 (s, 1H), 2.38 (s, 3H). 13C
2
NMR: d (CD3OD, 125 MHz) 170.0, 139.4, 134.5, 130.9,
(q, JCF=27.1 Hz). 19F NMR: d ꢂ73.42, ꢂ109.72. IR
1
129.3, 127.4, 125.5 (q, JCF=284 Hz), 123.6, 79.4 (q,
(KBr): 3501, 3270, 1699 cmꢂ1. APCI MS m/z: 220.3
(M+H+). HRMS (EI): calcd for C9H7F4NO2,
237.0413; found, 237.0417. Anal. calcd for C9H7F4NO2:
C, 45.58; H, 2.98; N, 5.91. Found: C, 45.43; H, 3.00; N,
5.91.
2JCF=27 Hz), 22.0. 19F NMR: d ꢂ73.10. IR (KBr):
3401, 1651 cmꢂ1. APCI MS m/z: 216.1 (M-OH). HRMS
(EI): calcd for C10H10F3NO2, 233.0664; found.
233.0673. Anal. calcd for C10H10F3NO2: C, 51.51; H,
4.32; N, 6.01. Found: C, 51.90; H, 4.20; N, 6.06.
5.1.50.
3,3,3-Trifluoro-2-(4-fluoro-phenyl)-2-hydroxy-
5.1.46. 3,3,3-Trifluoro-2-hydroxy-2-p-tolyl-propionamide
(43). General Procedure C was employed with 32 (2.0
g, 9.3 mmol) and concd HCl (2.0 mL). The hydroxy-
amide was obtained as a white solid (2.1 g, 97%):
propionamide (47). General Procedure C was employed
with 36 (3.2 g, 14.6 mmol) and concd HCl (2.0 mL). The
hydroxyamide was obtained as a white solid (3.2 g,
93%): mp=83–84 ꢀC. H NMR: d (CDCl3, 300 MHz)
1

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
991
7.63–7.67 (m, 2H), 7.08–7.13 (m, 2H), 5.95 (d, J=88.5
Hz, 2H), 4.64 (s, 1H). 13C NMR: d (CDCl3, 75 MHz)
169.1, 163.3 (d, JCF=248 Hz), 143.2, 128.5, 128.3 (d,
min, 2,6-lutidine (1.9 mL, 16.5 mmol) was added.
After 10 min, tert-butyldimethylsilyltrifluoromethane-
sulfonate (2.8 mL, 12.0 mmol) was added dropwise. The
reaction mixture was allowed to stir at room temper-
ature for 2 h and then quenched with saturated NH4Cl.
The mixture was extracted with CH2Cl2, dried over
MgSO4, filtered, and concentrated. Purification was
performed on a flash column (4:1 hexanes–EtOAc),
collecting all fractions with a component of Rf=0.71 to
yield the product as a white solid (3.6 g, 99%): mp=91–
93 ꢀC. 1H NMR: d (CDCl3, 300 MHz) 7.55–7.56 (m,
2H), 7.39–7.41 (m, 3H), 7.17 (s, 1H), 6.76 (s, 1H), 0.94
(s, 9H), ꢂ0.74 (d, J=32 Hz, 6H). 13C NMR: d
(CD3OD, 125 MHz) 171.5, 135.3, 129.5, 128.5, 127.4,
125.5, 125.1 (q, 1JCF=285 Hz), 121.6, 83.0 (q, 2JCF=33
Hz), 25.8, 18.6, ꢂ3.8, ꢂ4.1. IR (KBr): 3438, 3285, 2956,
2931, 2860, 2887, 1708 cmꢂ1. APCI MS m/z: 334.1
(M+H+).
1
2JCF=223 Hz), 123.5 (q, JCF=284 Hz), 115.9 (d,
1
2
3JCF=116 Hz), 79.1 (q, JCF=23 Hz). 19F NMR: d
ꢂ73.64, ꢂ110.37. IR (KBr): 3409, 1710 cmꢂ1. APCI MS
m/z: 236.0 (M-Hꢂ). HRMS (FAB M+H+): calcd for
C9H8F4NO2, 238.1519; found, 238.0503. Anal. calcd
for C9H7F4NO2: C, 45.58; H, 2.98; N, 5.91. Found: C,
45.73; H, 2.98; N, 6.01.
5.1.51.
3,3,3-Trifluoro-2-hydroxy-2-(3-trifluoromethyl-
phenyl)-propionamide (48). General Procedure C was
employed with 37 (1.11 g, 4.1 mmol) and concd HCl
(0.8 mL). The hydroxyamide was obtained as a white
ꢀ
1
solid (.90 g, 76%): mp=56–59 C. H NMR: d (CDCl3,
300 MHz) 7.96 (s, 1H), 7.90 (d, J=8.1 Hz, 1H), 7.69 (d,
J=7.5 Hz, 1H), 7.55 (t, J=7.5 Hz, 1H), 6.43 (s, 2H),
5.06 (s, 1H). 13C NMR: d (CDCl3, 75 MHz) 169.8, 160.4
(q, 2JCF=164 Hz), 134.6, 131.4 (q, 3JCF=132 Hz), 129.6
(q, 4JCF=28 Hz), 126.7, 123.6 (q, 1JCF=271 Hz), 123.3,
5.1.55. 2-(tert-Butyl-dimethyl-silanyloxy)-3,3,3-trifluoro-
N-methyl-2-phenyl-propionamide (52).18 To a solution
of 51 (3.0 g, 9.0 mmol) in dry DMF (60 mL) was added
NaH (432 mg, 10.8 mmol, 60% dispersion in mineral
oil). The mixture was allowed to stir for 20 min or the
conclusion of the evolution of H2 gas. The reaction
mixture was cooled to 0 ꢀC and methyl iodide (0.56 mL,
9.0 mmol) was added dropwise. The mixture was
allowed to slowly warm to room temperature and stir
for 4 h. The mixture was diluted with Et2O, washed with
H2O, dried over MgSO4, filtered, and concentrated.
Purification was performed on a flash column (3:1 hex-
anes–EtOAc), collecting all fractions with a component
of Rf=0.40 to yield the product as a white solid (2.75 g,
1
2
123.2 (q, JCF=285 Hz), 81.1 (q, JCF=24 Hz). 19F
NMR: d ꢂ61.63, ꢂ73.44. IR (KBr): 3491, 3335, 1699
cmꢂ1. APCI MS m/z: 288.0 (M+H+). HRMS (EI):
calcd for C10H8F6NO3, 288.0459; found, 288.0460.
Anal. calcd for C10H7F6NO2: C, 41.83; H, 2.46; N, 4.88.
Found: C, 41.92; H, 2.35; N, 4.95.
5.1.52. 3,3,4,4,4-Pentafluoro-2-hydroxy-2-phenyl-butyro-
nitrile (49). 2,2,2-,2,3,3,3-Pentafluoro-1-phenyl propan-
1-one (2.0 g, 8.9 mmol) in a minimal amount of dry
CH2Cl2 was cooled to 0 ꢀC and TiCl4 (1.2 mL, 10.7
mmol) was added dropwise. After 30 min, TMSCN (1.2
mL, 8.9 mmol) was added. The mixture was brought to
room temperature and allowed to stir for 6 h. The
reaction was quenched with water (30 mL) and the
organic layer was washed with saturated NaHCO3 (30
mL), dried over MgSO4, filtered, and concentrated to
yield a yellow oil (1.8 g, 80%). IR (neat): 3363, 2965,
88%): mp=71–74 ꢀC. H NMR: d (CDCl3, 300 MHz)
1
7.49–7.52 (m, 2H), 7.35–7.40 (m, 3H), 6.69 (s, 1H), 2.90
(d, J=5.1 Hz, 3H), 0.96 (s, 9H), 0.05 (d, J=25.5 Hz,
6H). 13C NMR: d (CDCl3, 125 MHz) 168.5, 135.6,
129.3, 128.4, 127.3, 123.6 (1JCF=287 Hz), 81.7
(2JCF=27 Hz), 26.2, 25.8, 18.6, ꢂ3.9, ꢂ4.2. IR (KBr):
3445, 2956, 2859, 1683 cmꢂ1. APCI MS m/z: 348.0
(M+H+).
2883, 2220 cmꢂ1
.
5.1.53. 3,3,4,4,4-Pentafluoro-2-hydroxy-2-phenyl-butyra-
mide (50). General Procedure C was employed with 49
(1.8 g, 7.2 mmol) and concd HCl (3.0 mL). The
hydroxyamide was obtained as a white solid (1.1 g,
5.1.56.
3,3,3-Trifluoro-2-hydroxy-N-methyl-2-phenyl-
propionamide (53). A solution of 52 (2.75 g, 7.9 mmol)
in dry THF (80 mL) was cooled to 0 ꢀC, followed by the
addition of tetrabutylammonium fluoride (1.0M in
THF, 9.5 mL, 9.5 mmol). The reaction mixture was
allowed to warm to room temperature and stir for 16 h.
The reaction was quenched with saturated NH4Cl,
extracted with Et2O, dried over MgSO4, filtered, and
concentrated. Purification was performed on a flash
column (1:1 hexanes–EtOAc), collecting all fractions
with a component of Rf=0.50 to yield the product as a
ꢀ
1
57%): mp=98–99 C. H NMR: d (CDCl3, 300 MHz)
7.71–7.73 (m, 2H), 7.41–7.45 (m, 3H), 6.15 (d, J=39.3
Hz, 2H), 5.00 (s, 1H). 13C NMR: d (CD3OD, 125 MHz)
172.9, 136.5, 130.7, 130.0, 129.1, 127.7, 120.7 (q of t,
1
1JCF=60 and 477 Hz), 115.2 (t of q, JCF=57 and 444
2
Hz), 78.3 (t, JCF=37 Hz). 19F NMR: d ꢂ76.84,
ꢂ115.26 (dd, J=281 and 543 Hz). IR (KBr): 3373, 1683
cmꢂ1. EI+ MS m/z: 270.1 (M+H+). HRMS (EI): calcd
for C10H8F5NO2, 269.0475; found, 269.0469. HPLC
mBondapak C18 column (A: 0.1% TFA in H2O, B:
0.1% TFA in 1:1 CH3CN:H2O, B increased from 5 to
10% over 30 min, one peak at 10.59 min) (B: 0.1% TFA
in H2O, B: 0.1% TFA in MeOH, B increased from 5 to
10% over 30 min, one peak at 12.39 min).
white solid (1.7 g, 93%). mp=139–140 ꢀC. H NMR: d
1
(CDCl3, 300 MHz) 7.60–7.63 (m, 2H), 7.40–7.43 (m,
3H), 6.05 (s, 1H), 4.85 (s, 1H), 2.88 (d, J=2.7 Hz, 3H).
13C NMR: d (CD3OD, 125 MHz) 167.8, 134.4, 129.5,
128.9, 126.3, 125.6 (q, 1JCF=284 Hz), 79.4 (q, 2JCF=27
Hz), 27.3. 19F NMR: d ꢂ73.05. IR (KBr): 3436, 2357,
1675 cmꢂ1 APCI MS m/z: 234.0 (M+H+). HRMS (EI):
calcd for C10H10F3NO2, 233.0664; found, 233.0667.
Anal. calcd for C10H10F3NO2: C, 51.51; H, 4.32; N,
6.01. Found: C, 51.77; H, 4.48; N, 5.94.
5.1.54. 2-(tert-Butyl-dimethyl-silanyloxy)-3,3,3-trifluoro-
2-phenyl-propionamide (51). A 0.1M solution of 1 (2.4g,
11.0 mmole) in dry CH2Cl2 was cooled to 0 ꢀC. After 30

992
H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
5.1.57. 3,3,3-Trifluoro-2-methoxy-2-phenyl-propionamide
(54).18 To a solution of 1 (500 mg, 2.28 mmol) in dry
DMF (20 mL) was added NaH (110 mg, 2.74 mmol,
60% dispersion in mineral oil). The mixture was
allowed to stir for 20 min or the conclusion of the evo-
lution of H2 gas. The reaction mixture was cooled to
0 ꢀC and methyl iodide (0.14 mL, 2.28 mmol) was added
dropwise. The mixture was allowed to slowly warm to
room temperature and stir for 2 h. The mixture was
diluted with Et2O, washed with H2O, dried over
MgSO4, filtered, and concentrated. Purification was
performed on a flash column (1:1 hexanes–EtOAc),
collecting all fractions with a component of Rf=0.40 to
yield the product as a white solid (470 mg, 89%):
ture, Et2O and H2O were added and the aqueous layer
was extracted with Et2O. The combined Et2O layers
were dried over MgSO4, filtered, and concentrated.
Purification was performed on a flash column (9:1 hex-
anes–Et2O), collecting all fractions with a component of
Rf=0.80 to yield the product as a yellow solid. (2.0 g,
77%): mp=35–37 ꢀC. H NMR: d (CDCl3, 300 MHz)
1
8.59 (s, 1H), 8.04 (d, J=8.4 Hz, 1H), 7.96 (d, J=8.1 Hz,
1H), 7.88 (t, J=8.4 Hz, 2H), 7.67 (t, J=7.8 Hz, 1H),
7.58 (t, J=7.2 Hz, 1H). 13C NMR: d (CDCl3, 125 MHz)
180.2 (q, 2JCF=35 Hz), 136.3, 132.9, 132.0, 129.9, 129.8,
1
128.8, 127.7, 127.2, 123.9, 116.9 (q, JCF=290 Hz). IR
(KBr): 3052, 2958, 2929, 2872 cmꢂ1. EI MS m/z: 228.2.
mp=67–69 ꢀC. H NMR: d (CDCl3, 300 MHz) 7.55–
5.1.60. 3,3,3-Trifluoro-2-hydroxy-2-naphthalen-2-yl-pro-
pionitrile (57). General Procedure B was employed with
56 (610 mg, 2.7 mmol), TMSCN (4.0 mL, 30 mmol),
KCN (30 mg) and 18-crown-6 (30 mg). The cyanohy-
drin was obtained as a white solid (620 mg, 91%). IR
1
7.56 (m, 2H), 7.38–7.40 (m, 3H), 6.53 (d, J=87.3 Hz,
2H), 3.42 (s, 3H). 13C NMR: d (CD3OD, 125 MHz)
169.2, 129.6, 128.6, 127.6, 125.6, 125.4 (q, JCF=288
1
2
19
Hz), 85.4 (q, JCF=26 Hz) 55.0. F NMR: d ꢂ67.94.
IR (KBr): 3477, 2953, 2849, 1699 cmꢂ1. APCI MS m/z:
234.1 (M+H+). HRMS (EI): calcd for C10H10F3NO2,
234.0742; found, 234.0736. Anal. calcd for
C10H10F3NO2: C, 51.51; H, 4.32; N, 6.01. Found: C,
51.63; H, 4.25; N, 6.04.
(neat): 3370, 2960, 2875, 2141 cmꢂ1
.
5.1.61. 3,3,3-Trifluoro-2-hydroxy-2-naphthalen-2-yl-pro-
pionamide (58). General Procedure C was employed
with 57 (620 mg, 2.5 mmol) and concd HCl (3.0 mL).
The hydroxyamide was obtained as a white solid (470
5.1.58. 3-Hydroxy-1-methyl-3-trifluoromethyl-1,3-dihy-
dro-indol-2-one (55).19 Anhydrous KF (0.47 g, 5.0
mmol) and a solution of methyl-isatin (4.0 g, 24.8
mmol) in dry THF (100 mL) was added dropwise via
syringe, followed by trimethyl(trifuoromethyl)silyl
(TMSCF3, 5.5 mL, 37.2 mmol). A saturated solution of
t-BuOK in dry THF (30 mL) was added until the reac-
tion began to reflux. The mixture was brought to room
temperature and allowed to stir for 2 h. The mixture
was extracted with hexanes (3ꢃ40 mL), dried over
MgSO4, filtered and concentrated. The crude product
was dissolved in dry THF (5 mL), cooled to 0 ꢀC, and
15% HCl (6 mL) was added and allowed to stir for 15
min. The mixture was extracted with hexanes (3ꢃ40
mL), dried over MgSO4, filtered, and concentrated.
Purification was performed on a flash column (10:1
CH2Cl2–acetone), collecting all fractions containing a
component of Rf=0.81 to yield the product as a yellow
solid (2.0 g, 35%): mp=168–170 ꢀC. 1H NMR: d
(CDCl3, 300 MHz) 7.0–7.5 (m, 5H), 4.75 (s, 1H), 3.18 (s,
3H). 13C NMR: d (CD3OD, 125 MHz) 171.8, 144.8,
mg, 71%): mp=94–96 ꢀC. 1H NMR:
d (CDCl3,
300 MHz) 8.15 (s, 1H), 7.83–7.91 (m, 3H), 7.67 (d,
J=8.7 Hz, 1H), 7.50–7.55 (m, 2H), 5.99 (d, J=72.3 Hz,
2H), 4.86 (s, 1H). 13C NMR: d (CDCl3, 125 MHz)
169.0, 133.1, 132.4, 130.9, 128.6, 128.2, 127.3, 127.0,
1
126.5, 125.7, 123.4 (q, JCF=280 Hz), 122.9, 78.2 (q,
2JCF=28 Hz). 19F NMR: d ꢂ73.04. IR (KBr): 3387,
2961, 2359, 1695 cmꢂ1. APCI MS m/z: 252.2 (M-OH-).
HRMS (EI): calcd for C13H10F3NO2, 269.0664; found,
269.0658. HPLC mBondapak C18 column (A: 0.1%
TFA in H2O, B: 0.1% TFA in 1:1 CH3CN:H2O, B
increased from 5 to 10% over 30 min, one peak at 27.06
min) (B: 0.1% TFA in H2O, B: 0.1% TFA in MeOH, B
increased from 5 to 10% over 30 min, one peak at 29.95
min).
6. Biology
6.1. Cell culture
1
131.8, 125.8, 125.7, 124.8 (q, JCF=284 Hz), 124.5,
HEK-293 cells stably expressing a human T-type cal-
cium channel, (hCav3.2) a1H,29 were a kind gift from
Dr. Edward Perez-Reyes, at the University of Virginia.
Cells were maintained in DMEM containing 10% fetal
bovine serum with 1mg/mL G418. Cells were enzymati-
cally dissociated with 0.05% trypsin plus 1mM EDTA
for 1 min. Cells were then diluted with DMEM and
plated on glass coverslips or poly-l-lysine coated cover-
slips and were incubated for 1–4 h prior to electro-
physiological studies.
2
123.6, 123.5, 109.4, 76.3 (q, JCF=30 Hz), 25.8. 19F
NMR: d ꢂ78.55. IR (KBr): 3302, 1717 cmꢂ1. APCI MS
m/z: 232.0 (M+H+). HRMS (EI): calcd for
C10H8F3NO2, 231.0507; found, 231.0509. Anal. calcd
for C10H8F3NO2: C, 51.96; H, 3.49; N, 6.06. Found: C,
52.22; H, 3.45; N, 6.01.
5.1.59. 2,2,2-Trifluoro-1-naphthalen-2-yl-ethanone (56).20
NMP (85 mL) and phenyl trifluoroacetate (distilled
under reduced pressure, 15 mmHg, 51 ꢀC, 2.17 mL,
14.53 mmol) were degassed overnight with argon. 2-
Naphthaleneboronic acid (3.0 g, 17.44 mmol), tributyl-
phosphine (distilled under reduced pressure, 15 mmHg,
115 ꢀC, 0.54 mL, 2.18 mmol) and Pd(OAc)2 (166 mg,
0.74 mmol) were added and the reaction mixture was
heated at 80 ꢀC for 4 h. After cooling the reaction mix-
6.2. Patch clamp electrophysiology
Calcium currents were recorded from HEK-293 cells
stably expressing the Cav3.2a1H channels using the
whole-cell configuration of the patch clamp recording
technique with an Axopatch 200B amplifier (Axon

H. A. Schenck et al. / Bioorg. Med. Chem. 12 (2004) 979–993
6. Perez-Reyes, E. Physiol. Rev. 2003, 83, 117.
993
Instruments, Foster City, CA). All voltage protocols
were applied using pCLAMP 8 software (Axon, USA)
and a Digidata 1322A (Axon). Currents were amplified
and low pass filtered (2 kHz) and sampled at 10 kHz.
Borosilicate glass pipettes were pulled using a Brown-
Flaming puller (model -P87, Sutter Instruments Co,
Novato, CA) and heat polished to produce electrode
resistances of 0.7–1.7 Mꢀ when filled with the following
electrode solution (in mM) CsCl 135, MgATP 4,
Na3GTP 0.3, EGTA 10, HEPES 10 (pH adjusted to 7.3
with CsOH). Cells were superfused at 1 mL/min with
the following solution (in mM) CaCl2 5, tetra-
ethylammonium (TEA) chloride 155, HEPES 10, (pH
adjusted to 7.4 with TEA-OH). The compound was
prepared as 100 mM stock solution in DMSO and
diluted to desired concentrations in perfusion solution.
All experiments were performed at room temperature
(20–22 ꢀC) with continuous perfusion. Cells were held at
ꢂ110 mV and a step to ꢂ20 mV for 150 ms was applied,
this was repeated a total of 100 times at a frequency of 1
Hz. Compound was applied at increasing concentra-
tions followed by washout and use dependent blocking
data were acquired in this manner.
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Acknowledgements
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The authors would like to thank the Department of
Chemistry and the Burger Center for Drug Discovery
for financial support. PL would like to thank the Car-
diovascular Training Grant for support and Dr.
Edward Perez-Reyes for the T-type calcium channels
and HEK 293 cells.
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