Discovery of dihydrothieno- and dihydrofuropyrimidines as potent pan Akt inhibitors

Article abstract of DOI:10.1016/j.bmcl.2010.09.112

Herein we report the discovery and synthesis of a novel series of dihydrothieno- and dihydrofuropyrimidines (2 and 3) as potent pan Akt inhibitors. Utilizing previous SAR and analysis of the amino acid sequences in the binding site we have designed inhibi

Full text of DOI:10.1016/j.bmcl.2010.09.112

Bioorganic & Medicinal Chemistry Letters 20 (2010) 7037–7041
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Discovery of dihydrothieno- and dihydrofuropyrimidines as potent pan
Akt inhibitors
Josef R. Bencsik a, , Dengming Xiao a, James F. Blake a, Nicholas C. Kallan a, Ian S. Mitchell a, Keith L. Spencer a,
⇑
Rui Xu a, Susan L. Gloor a, Matthew Martinson a, Tyler Risom a, Richard D. Woessner a, Faith Dizon a,
Wen-I Wu a, Guy P. A. Vigers a, Barbara J. Brandhuber a, Nicholas J. Skelton b, Wei Wei Prior b,
Lesley J. Murray b
a Array BioPharma Inc., 3200 Walnut Street, Boulder, CO 80301, USA
b Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080-4990, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Herein we report the discovery and synthesis of a novel series of dihydrothieno- and dihydrofuropyrim-
idines (2 and 3) as potent pan Akt inhibitors. Utilizing previous SAR and analysis of the amino acid
sequences in the binding site we have designed inhibitors displaying increased PKA and general kinase
selectivity with improved tolerability compared to the progenitor pyrrolopyrimidine (1). A representative
dihydrothieno compound (34) was advanced into a PC3-NCI prostate mouse tumor model in which it
demonstrated a dose-dependent reduction in tumor growth and stasis when dosed orally daily at
200 mg/kg.
Received 25 August 2010
Revised 20 September 2010
Accepted 22 September 2010
Available online 29 September 2010
Keywords:
Akt
Kinase
Selectivity
Oral
Ó 2010 Elsevier Ltd. All rights reserved.
PKA
There is a growing wealth of evidence implicating the PI3K
pathway in the progression of various forms of cancer.1 A central
player within this pathway is the serine/threonine kinase Akt also
known as Protein Kinase B (PKB), which is a member of the AGC
family of kinases and shares high homology with PKA and PKC.
There are three closely related Akt isoforms, Akt1, Akt2 and Akt3,
all of which share greater than 80% sequence identity in the kinase
domain.2 Up-regulation of Akt activity has been shown to be an
important mechanism in the development, maintenance and
growth of various forms of cancer.3 As Akt has emerged as an
attractive anticancer target, several small molecule Akt inhibitors
have recently been reported.4
tivity over this closely related kinase would likely improve the
overall kinase selectivity. Our earlier efforts identified a trend that
led to improved PKA selectivity, namely increased substitution
near the gatekeeper residue.5 Examination of published8 and inter-
nally generated co-crystal structures of PKA indicated that PKA
possesses a smaller, more lipophilic pocket in the hinge region, rel-
ative to Akt1 (cf. Fig. 2). We hypothesized that selectivity over PKA
could be obtained either by increasing the size of the hinge binding
core in this region, or by modulating the polarity. Herein we
describe the identification and development of a novel series of
In a previous report we described the discovery of a novel class
of pyrrolopyrimidine pan Akt inhibitors (1, Fig. 1).5 Although these
compounds exhibited excellent potency against Akt, their progres-
sion was impaired due to a lack of tolerability in rodents, which
was thought to arise from their overall kinase inhibition profile.
Of particular concern were the closely related kinases PKA6 and
Rho-associated kinase (ROCK)7 both of which are implicated in var-
ious cardiovascular processes. In order to address the selectivity
profile of compounds such as 1, we chose to target PKA, since selec-
NH
F
NH
NH2
O
O
N
O
N
N
N
N
N
N
Cl
Cl
N
N
O
S
N
H
N
N
N
1
2
3
⇑
Corresponding author.
E-mail address: jbencsik@arraybiopharma.com (J.R. Bencsik).
Figure 1. Pan Akt inhibitors featuring the pyrrolo-, dihydrothieno-, and dihydrof-
uro-pyrimidine cores.
0960-894X/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2010.09.112

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J. R. Bencsik et al. / Bioorg. Med. Chem. Lett. 20 (2010) 7037–7041
15. Hydrolysis of the lactam revealed the desired c-amino acids 16
in good yield. Subsequent amide coupling of core 11 with the de-
sired amino acid under standard conditions, followed by Boc
deprotection under acid conditions afforded the final compounds
in excellent yield.
As previously described, compounds were evaluated in several
primary in vitro assays: enzyme inhibition of Akt (all three iso-
forms), PKA (IMAP format), and the cellular inhibition of p-PRAS40
formation in LNCaP cells.5 Early research focused on the unsubsti-
tuted dihydrothieno-pyrimidine 17 containing the 4-Cl phenylala-
nine amino amide. In accordance with our design hypothesis, 17
showed moderate enzyme and cellular Akt activity and improved
PKA selectivity (10-fold) compared to 1 (Table 1). Replacing the
sulfur of 17 with a sulfone 189 enhanced the template’s selectivity
over PKA to 25-fold but lost cellular potency, presumably due to
poor cell permeability.
Substitution at the R2-position (Table 1) of the core with either
methyl 19 or ethyl 20 increased potency, with little effect on selec-
tivity, consistent with earlier reported SAR trends in this region of
the molecule.5 Interestingly, the 5-position of the saturated dihy-
drothieno core affords stereospecific access to the lipophilic pock-
et. The (S)-methyl stereoisomer 21, by virtue of being able to access
this lipophilic pocket, was found to be significantly more potent
than the (R) isomer 22 with no loss of selectivity over PKA.
Various phenyl ring substitutions 23–25 were investigated at
the 3- and 4-positions. As in the pyrrolopyridine series, increased
lipophilicity afforded only slight improvements in potency. Despite
losing both enzyme and cellular potency, incorporation of an in-
dole 26 demonstrated enhanced PKA selectivity of greater than
35-fold suggesting that the amino amide region also contributes
towards selectivity.
In order to address concerns of the possible oxidative liabilities
inherent to the dihydrothieno core as well as probe the effects of
an oxygen heteroatom on potency and selectivity, several dihy-
drofuropyrimidine analogs were evaluated. Generally the dihy-
drofuropyrimidine analogs (27 vs 21) were found to be less
potent while maintaining PKA selectivity relative to their dihydro-
thieno counterparts.
Figure 2. Comparison of the X-ray structures of 26 bound to Akt1 (orange) and PKA
(grey). Solvent accessible surfaces depicted, Akt1 numbering used. (PDB code:
Akt1—3OW4 and PKA—3OW3)10
potent Akt inhibitors with improved selectivity based on the dihy-
drothieno- (2) and dihydrofuropyrimidine scaffolds (3).
Synthesis of the requisite pyrimidine cores originated from Mi-
chael addition of the corresponding methyl 2-hydroxyacetate or
mercaptoacetate 4 with a suitable crotonate ester 5 under mild
conditions furnishing bis-ester
6 in near quantitative yield
(Scheme 1). Subsequent Dieckmann cyclization to keto-ester 7, fol-
lowed by condensation with formamidine in the presence of so-
dium ethoxide, led to pyrimidinol 8. Smooth conversion of 8 to
chloride 9 was carried out with POCl3 in acetonitrile. Incorporation
of the piperazine linker 10 by heating in NMP or tert-butyl alcohol,
followed by liberation of the protecting group, cleanly afforded 11
as the bis-HCl salt in excellent yield. Enantiomerically pure mate-
rial was obtained from the racemic mixture via chiral HPLC or SFC
separation.
X-ray crystallography of the kinase domains of Akt1 and PKA
indicates that the dihydrothieno pyrimidine core binds to both
enzymes in a similar fashion (Fig. 2). Our strategy for achieving
selectivity exploited key differences in the binding pocket between
Akt1 and PKA. These subtle changes include a Thr211 (Akt1) to Val
(PKA), Met281 (Akt1) to Leu, and Ala230 (Akt1) to Val. These
differences produce a narrower cavity in PKA, and should be less
forgiving of larger substitutions.11 Therefore the dihydrothieno-
pyrimidine 17 by virtue of a saturated ring and bulkier sulfur atom
near the gatekeeper displays PKA selectivity upwards of 10-fold
The
either derived from commercial sources or synthesized as previ-
ously described.5 Synthesis of the
-amino acids was achieved as
described in Scheme 2. Hydromethylation of the appropriately
substituted phenyl acetic esters 12 followed by mesylate activation
and elimination afforded acrylates 13 in excellent yields. Introduc-
tion of the desired nitroalkane to acrylates 13 in a Michael fashion
afforded adducts 14. Reduction of the nitro group in the presence
of excess zinc dust and hydrochloric acid followed by concomitant
cyclization and protection to the tert-butyl carbamate gave lactams
a- and b-amino acid components reported herein were
c
O
O
O
CO2Me
b
a
+
RH
R
OMe
R
MeO
OMe
MeO
O
R = O,S
O
R= S, 93%
R= O, 74% for
6
7
4
5
2 steps
R = S, 98%
c
H
N
Cl
OH
N
Boc
N
2 HCl
d
e-f
+
N
N
N
N
R
R
R
N
H
10
N
N
R = S, 76%
R = O, 75%
R = S, 38%
R = O, 29%
R = S, 94%
R = O, 89%
11
9
8
Scheme 1. Reagents and conditions: (a) 1.2 equiv 4, 0.05 equiv piperidine, neat, rt, 12 h; (b) 1.2 equiv NaOMe, toluene, reflux, 6 h; (c) 1.1 equiv formamidine, 1.0 equiv NaOEt,
EtOH, reflux, 12 h; (d) 10 equiv POCl3, CH3CN, reflux, 2 h; (e) 1.2 equiv 10, NMP or tert-BuOH, 90 °C, 12 h; (f) 5 equiv 4 N HCl in dioxane, DCM, 4 h.

J. R. Bencsik et al. / Bioorg. Med. Chem. Lett. 20 (2010) 7037–7041
7039
NO2
R1
R2
a-b
c
CO2Me
CO2Me
CO2Me
R
R
R
14
12
13
d,e
R1
NHBoc
R2
R1
R2
f
NBoc
CO2H
R
R
O
16
15
Scheme 2. Reagents and conditions: (a) paraformaldehyde, 10% NaOMe, DMSO, rt, 12 h, 98%; (b) MsCl, 2.5 equiv TEA, DCM, 0 °C to rt, 12 h, 95%; (c) 1.2 equiv NO2CHR1R2,
1.2 equiv DBU, CH3CN, 0 °C to rt, 12 h, 80–95%; (d) 10 equiv Zn dust, 4 equiv concd HCl, EtOH, reflux, 6 h, 80%. (e) 1.1 equiv LHMDS, 1.2 equiv Boc2O, À78 °C to rt, 3 h, 95%; (f)
3 equiv LiOH–H2O, THF/MeOH/H2O (3:1:1), 0 °C to rt, 4 h, 89%.
Table 1
a
-Amino amide series SAR
NH2
R3
O
N
N
R2
R1
N
N
a
a
Compound
R1
R2
R3
Akt1 Enz IC50 (nM)
PKA Enz IC50 (nM)
Akt cell IC50 LNCaPb (nM)
160
3846 100
21,010 1100
310 20
1201 150
184 89
18,469 1198
176 15
1592 22
602 35
3629 248
615 119
1
—
S
SO2
S
S
S
S
S
S
S
—
H
H
Me
—
3.0
22
2
6
6
2
2
17
18
19
20
21
22
23
24
25
26
27
4-Cl-Ph
4-Cl-Ph
4-Cl-Ph
4-Cl-Ph
4-Cl-Ph
4-Cl-Ph
3-F, 4-Cl-Ph
4-F-Ph
223 41
1300 499
52 19
4
7
1
1
2
0
31
52
13
5
8
1
Et
(S)-Me
(R)-Me
(S)-Me
(S)-Me
(S)-Me
(S)-Me
(S)-Me
260 61
1710 93
2
11
4
22
7
0
4
0
3
3
8
2
104 25
30
742 69
61
3,4-DiF-Ph
3-Indole
4-Cl-Ph
4
S
O
6
Akt2 potency was generally 5–10-fold less than Akt1, while Akt3 potency was generally 3–6-fold less than Akt1 (data not shown).
a
Values are means of three or more experiments, standard deviation is given.
Values are means of two or more experiments, standard deviation is given.
b
over Akt1 compared to 3-fold for pyrrolopyrimidine (1). Oxidation
of the sulfide to the sulfone 18 would place an oxygen atom of the
sulfone near the hydroxyl side chain of Thr211 in Akt1. By contrast
the Val of PKA at this position would place the sulfone oxygen in an
unfavorable lipophilic environment, resulting in both a loss of PKA
potency and enhanced selectivity to 25-fold. In order to capitalize
on the amino amide contribution towards selectivity, several
substituted b-amino amides were prepared (Table 2). In contrast
to the cyclopropyl primary amine 28, the secondary 29 and tertiary
30 amines demonstrated excellent enzyme and cellular potency,
with greater than 25-fold PKA selectivity.
Only modest changes in potency were observed through differ-
ent phenyl substituent with the 4-methyl 31 and 4-Cl 29 found to
be nearly equipotent. The 3-F, 4-Cl 32 substituent exhibited a slight
improvement in the cellular potency at the expense of selectivity,
the less lipophilic 3,4-diF 33 lost potency, while retaining selectivity.
Similar to our earlier report5 the (S)-b amino stereochemistry of 34
was found to be significantly more potent than the (R) isomer 35.12
Further carbon extension of the b-amino amides to provide the
-amino amide analogs were also investigated. The most potent
analogs were found to contain substitution alpha to the primary
amine such as the cyclopropyl 36 or the gem dimethyl (37 and
c
38). However, the best c-amino amide analogs were found to be
generally 2–3-fold less potent on Akt1 and less selective than the
corresponding b-amino amides. Several dihydrofuropyrimidine
analogs covering both the b- (39 vs 31, 40 vs 32, 41 vs 34) and
c
-amino amides (42 vs 38) were synthesized and similar to that
observed in the -amino amide series, were found to be less potent
a
and PKA selective relative to their dihydrothieno counterparts.
Having identified several potent compounds with modest selec-
tivity over PKA, representatives from the dihydrothieno- 2913 and
dihydrofuropyrimidine 41 series were screened against a panel of
40 related protein kinases at 1
improvement in overall kinase selectivity, inhibiting only three
enzymes at greater than 50% (PKA, p70S6K and PKC ), and com-
pared to earlier analogs bearing the pyrrolopyrimidine core (1)
lM. Both compounds exhibited an
g

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J. R. Bencsik et al. / Bioorg. Med. Chem. Lett. 20 (2010) 7037–7041
Table 2
b- and
a-Amino amide series SAR
R2
O
R3
N
N
N
R1
N
a
a
Compound
R1
R2
R3
Akt1 Enz IC50 (nM)
PKA Enz IC50 (nM)
Akt Cell IC50 LNCaPb (nM)
28
29
S
S
4-Cl
4-Cl
42
3
5
1
308 89
80 24
2468 111
159 30
NH2
–CH2NHisopropyl
N
30
S
4-Cl
3
0
75 16
178 11
-
31
32
33
34
35
S
S
S
S
S
–CH2NHisopropyl
–CH2NHisopropyl
–CH2NHisopropyl
(S)-CH2NHisopropyl
(R)-CH2NHisopropyl
4-Me
3-F,4-Cl
3,4-diF
4-Cl
3
2
10
1
0
0
1
0
101 11
216 69
92 22
759 67
30
285
35
3
9
3
137
ND
9
4-Cl
127 34
5620 635
36
S
3-F,4-Cl
3
1
30
8
250 17
NH2
37
38
39
40
41
42
S
S
O
O
O
O
–CH2C(CH3)2NH2
–CH2C(CH3)2NH2
–CH2NHisopropyl
–CH2NHisopropyl
(S)-CH2NHisopropyl
–CH2C(CH3)2NH2
4-Cl
3-F,4-Cl
4-Me
3-F,4-Cl
4-Cl
3-F,4-Cl
6
7
16
6
2
3
0
1
1
73 10
63 12
315 61
88 10
438 55
587 100
995 248
315 11
3
52
91
9
9
125
6
18 10
592 141
a
Values are means of three or more experiments, standard deviation is given.
Values are means of two or more experiments, standard deviation is given.
b
which showed greater than 50% inhibition in 23 of the 40 kinases
tested at a similar 1 M concentration.
a dose escalation PK/PD study in nude mice bearing subcutaneous
U87 human glioblastoma xenografts (Fig. 3).
l
Representative dihydrothieno- 34 and dihydrofuropyrimidine
41 analogs were evaluated in various in vitro ADME assays. Both
34 and 41 gave similar predicted clearance across species in hepa-
tocytes14 and liver microsomes. Metabolism studies identified that
amine de-alkylation, and not sulfur oxidation, as the major meta-
bolic reaction. Next, 34 was evaluated in rat PK and although the
clearance of 34 was high (Cl = 94 mL/min/kg) at 5 mg/kg iv, a sur-
prisingly high bioavailability (F >100%) with reasonable plasma
At the 1 and 4 h time points the plasma levels of 34 increased in
a linear fashion as the dose was increased from 50 to 100 mg/kg,
with little increase in exposure at the 200 mg/kg dose (possibly
as a result of solubility limited exposure). The corresponding p-
PRAS40 knockdown at 1 h was observed to be 85–90% starting at
the 50 mg/kg dose. At the 4 h time point p-PRAS40 knockdown
ranging from 60% (50 mg/kg) to 83% (200 mg/kg) was achieved.
At 12 h only the 200 mg/kg dose group demonstrated significant
(65%) p-PRAS40 knockdown. Based upon these results compound
levels (56.2 lg h/mL) was achieved when dosed at 50 mg/kg. Based
upon its selectivity, overall physiochemical properties, in vivo PK
profile and low plasma protein binding (compounds typically
range between 70% and 80% bound) we elected to advance 34 into
Vehicle (H2O)
Vehicle (H2O)
1000
800
600
400
200
0
2255mmg/gk/gkg
5500mmg/gk/gkg
110000mmg/gkg/kg
Tumor Inhibition
15 %
200mg/kg
200mg/kg
42
%
61 %
84 %
-2
0
2
4
6
8
10
12
14
Days on Treatment
Figure 4. Evaluation of 34 dosed QD at 25, 50, 100, and 200 mg/kg PO for 14 days in
Figure 3. Oral dose PK/PD of 34 in nude mice bearing U87 tumor xenografts. Four
mice per group. Compound dosed as a 10 mL/kg solution in water up to 100 mg/kg
and as a suspension at 200 mg/kg.
PC3-NCI prostate tumor bearing mice. Ten mice per group. Compound dosed as a
10 mL/kg solution in water up to 50 mg/kg and as
200 mg/kg.
a suspension at 100 and

J. R. Bencsik et al. / Bioorg. Med. Chem. Lett. 20 (2010) 7037–7041
7041
4. (a) Li, Q. Expert Opin. Ther. Targets 2007, 17, 1077; (b) Lindsley, C. W.; Barnett, S.
F.; Yaroschak, M.; Bilodeau, M. T.; Layton, M. E. Curr. Top. Med. Chem. 2007, 7,
1349; (c) Lindsley, C. W.; Barnett, S. F.; Layton, M. E.; Bilodeau, M. T. Curr.
Cancer Drug Targets 2008, 8, 7; (d) Lindsley, C. W. Curr. Top. Med. Chem. 2010,
10, 458.
5. Blake, J. F.; Kallan, N. C.; Xiao, D.; Xu, R.; Bencsik, J. R.; Skelton, N. J.; Spencer, K.
L.; Mitchell, I. S.; Woessner, R. D.; Gloor, S. L.; Risom, T.; Gross, S. D.; Martinson,
M.; Morales, T. H.; Vigers, P. A. G.; Brandhuber, B. J. Bioorg. Med. Chem. Lett.
2010, 20, 5607.
6. PKA is known to be an important mediator in the polarization of calcium
channels within the heart which when modulated could cause heart
arrhythmias. (a) Reiken, S.; Lacampagne, A.; Zhou, H.; Kherani, A.; Lehnart, S.
E.; Ward, C.; Haung, F.; Gaburjakova, M.; Gaburjakova, N.; Rosemblit, N.;
Warren, M. S.; He, K.; Yi, G.; Wang, J.; Burkhoff, D.; Vassort, G.; Marks, A. R. J.
Cell Biol. 2003, 160, 919; (b) Saucerman, J. J.; Zhang, J.; Martin, J. C.; Peng, L. X.;
Stenbit, A. E.; Tsien, R. Y.; McCulloch, A. D. Proc. Natl. Acad. Sci. U.S.A. 2006, 103,
2923; (c) Zakhary, D. R.; Moravec, C. S.; Bond, M. Circulation 2000, 101, 1459.
7. Rho-associated (ROCK) kinase has been shown to mediate vascular smooth
muscle cell contraction and stimulate vascular smooth muscle proliferation. (a)
Hu, E.; Lee, D. Expert Opin. Ther. Targets 2005, 9, 715; (b) Shimokawa, H.;
Takeshita, A. Arterioscler. Thromb. Vasc. Biol. 2005, 25, 1767; In addition there is
literature evidence suggesting that inhibition of ROCK would result in the
counterproductive activation of the PI3K/Akt1 pathway. Wolfrum, S.;
Dendorder, A.; Tikitake, Y.; Stalker, T. J.; Gong, Y.; Scalia, R.; Domaniak, P.;
Liao, J. K. Arterioscler. Thromb. Vasc. Biol. 2004, 24, 1842.
34 was progressed into a proof-of-concept tumor growth inhibi-
tion (TGI) study. Female nude mice were subcutaneously im-
planted with PC3-NCI prostate tumor cells and once established
to a tumor size of 150À200 mm3, 34 was dosed daily at 25, 50,
100 and 200 mg/kg PO for 14 days (Fig. 4). Compound 34 was
found to be well tolerated for the duration of the study and dem-
onstrated a dose-dependent reduction in tumor growth (P = 0.008
comparing 200 mg/kg dose with vehicle-dosed controls on day
14) with stasis observed at the highest dose. The observed TGI cor-
related well with the 14 day end of study 1 h and 4 h post dose PD
knockdown (data not shown).
In summary, we have described a novel class of oral pan Akt
inhibitors based upon the dihydrothieno- and dihydrofuropyrimi-
dine scaffolds. Integration of these cores with various amino acids,
led to the identification of several analogs displaying enhanced
PKA selectivity which was used as a surrogate for general kinase
selectivity. Compound 34 was found to be well tolerated in a
14 day PC3-NCI prostate cancer xenograft model, demonstrating
a
dose-dependent tumor reduction with stasis observed at
8. (a) Breitenlechner, C. B.; Wegge, T.; Berillon, L.; Graul, K.; Marzenell, K.; Friebe,
W.-G.; Thomas, U.; Schumacher, R.; Huber, R.; Engh, R. A.; Masjost, B. J. Med.
Chem. 2004, 47, 1375; (b) Breitenlechner, C. B.; Friebe, W.-G.; Brunet, E.;
Werner, G.; Graul, K.; Thomas, U.; Kuenkele, K.-P.; Schaefer, W.; Gassel, M.;
Bossemeyer, D.; Huber, R.; Engh, R. A.; Masjost, B. J. Med. Chem. 2005, 48, 163;
(c) Rouse, M. B.; Seefeld, M. A.; Leber, J. D.; McNulty, K. C.; Sun, L.; Miller, W. H.;
Zhang, S.; Minthorn, E. A.; Concha, N. O.; Choudhry, A. E.; Schaber, M. D.;
Heerding, D. A. Bioorg. Med. Chem. Lett. 2009, 19, 1508.
200 mg/kg oral daily dosing. Further refinements to improve po-
tency, kinase selectivity and overall ADME properties are currently
underway, the results of which will be reported in future
communications.
Acknowledgements
9. Oxidation of the dihydrothienopyrimidine 17 to the sulfone 18 was carried out
using 5 equiv of m-CPBA in 86% yield.
10. Atomic coordinates for structure 26 bound to Akt1 and PKA were deposited
with the RCSB Protien Data Bank (PDB) under the accession codes 3OW4 for
Akt1 and 3OW3 for the PKA.
The authors thank James M. Graham and Dr. Francis X. Sullivan
for helpful insight and discussion in the preparation of this Letter.
11. A similar observation and strategy was recently published by researchers in
their efforts to obtain Akt selectivity over ROCK1. Lin, H.; Yamashita, D. S.;
Zeng, J.; Xie, R.; Wang, W.; Nidarmarthy, S.; Luengo, J. I.; Rhodes, N.; Knick, V.
B.; Choudhry, A. E.; Lai, Z.; Minithorn, E. A.; Strum, S. L.; Wood, E. R.; Elkins, P.
A.; Concha, N. O.; Heerding, D. A. Bioorg. Med. Chem. Lett. 2010, 20, 673.
12. This stereochemical assignment is consistent with maintaining the same
Reference and notes
1. (a) Osaki, M.; Oshimura, M.; Ito, H. Apoptosis 2004, 9, 667; (b) Murillo, H.;
Huang, H.; Schmidt, L. J.; Smith, D. I.; Tindall, D. J. Endocrinology 2001, 142,
4795; (c) Sun, M.; Paciga, J. E.; Feldman, R. I.; Yuan, Z.; Coppola, D.; Lu, Y. Y.;
Shelley, S. A.; Nicosia, S. V.; Cheng, J. Q. Cancer Res. 2001, 61, 5985.
overall amine and phenyl orientation as observed in the (R)
a-amino amide
2. (a) Barnett, S. F.; Defeo-Jones, D.; Fu, S.; Hancock, P. J.; Haskell, K. M.; Jones, R.
E.; Kahana, J. A.; Kral, A. M.; Leander, K.; Lee, L. L.; Malinowski, J.; McAvoy, E.
M.; Nahas, D. D.; Robinson, R. G.; Huber, H. E. J. Biochem. 2005, 385, 399; (b)
Masure, S.; Haefner, B.; Wesselink, J. J.; Hoefnagel, E.; Mortier, E.; Verhasselt, P.;
Tuytelaars, A.; Gordon, R.; Richardson, A. Eur. J. Biochem. 1999, 265, 353.
3. (a) Yap, T. A.; Garrett, M. D.; Walton, M. I.; Raynaud, F.; de Bono, J. S.; Workman,
P. Curr. Opin. Pharm. 2008, 8, 393; (b) Datta, S. R.; Brunet, A.; Greenberg, M. E.
Genes Dev. 1999, 13, 2905; (c) Graff, J. R. Expert Opin. Ther. Targets 2002, 6, 103;
(d) Steelman, L. S.; Kristin, M. S.; Chappell, W. H.; Horn, S.; Basecke, J.; Cervello,
M.; Nicoletti, F.; Libra, M.; Stivala, F.; Martelli, A. M.; McCubrey, J. A. Expert
Opin. Ther. Targets 2008, 12, 1139.
series.
13. Historically the selectivity profiles obtained for both the racemic and
enantiopure analogs were found to be essentially identical within this series
and therefore the enantiopure data was not deemed critical in our decision to
progress 34.
14. The measured in vitro clearance of 34 in hepatocytes was found to be; mice
Cl = 23 mL/min/kg, rat Cl = 25 mL/min/kg and human Cl = 14 mL/min/kg. The
measured in vitro clearance of 41 in hepatocytes was found to be; mice
Cl = 22.8 mL/min/kg and human Cl = 13.8 mL/min/kg.