Identification of 2-oxatriazines as highly potent pan-PI3K/mTOR dual inhibitors

Article abstract of DOI:10.1016/j.bmcl.2011.06.063

We recently described several highly potent, triazine (1) and triazolopyrimidine (2) scaffold-based, dual PI3K/mTOR-inhibitors (e.g., 1, PKI-587) that were efficacious in both in vitro and in vivo models. In order to further optimize these compounds we devised a novel series, the 2-oxatriazines, which also exhibited excellent potency and good metabolic stability. Some 2-oxatriazines showed promising in vivo biomarker suppression and induced apoptosis in the MDA-MB-361 breast cancer xenograft model.

Full text of DOI:10.1016/j.bmcl.2011.06.063

Bioorganic & Medicinal Chemistry Letters 21 (2011) 4773–4778
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Identification of 2-oxatriazines as highly potent pan-PI3K/mTOR dual inhibitors
Christoph M. Dehnhardt a, , Aranapakam M. Venkatesan a, Zecheng Chen a, Efren Delos-Santos a,
⇑
Semiramis Ayral-Kaloustian a, Natasja Brooijmans b, Ker Yu c, Irwin Hollander c, Larry Feldberg c,
Judy Lucas c, Robert Mallon c
a Medicinal Chemistry, Pfizer, 401 N. Middletown Rd., Pearl River, NY 10965, USA
b Computational Chemistry, Pfizer, 401 N. Middletown Rd., Pearl River, NY 10965, USA
c Oncology, Pfizer, 401 N. Middletown Rd., Pearl River, NY 10965, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
We recently described several highly potent, triazine (1) and triazolopyrimidine (2) scaffold-based, dual
PI3K/mTOR-inhibitors (e.g., 1, PKI-587) that were efficacious in both in vitro and in vivo models. In order
to further optimize these compounds we devised a novel series, the 2-oxatriazines, which also exhibited
excellent potency and good metabolic stability. Some 2-oxatriazines showed promising in vivo biomarker
suppression and induced apoptosis in the MDA-MB-361 breast cancer xenograft model.
Ó 2011 Elsevier Ltd. All rights reserved.
Received 20 April 2011
Revised 12 June 2011
Accepted 14 June 2011
Available online 21 June 2011
Keywords:
Oxatriazine scaffold
PI3K
mTOR
Akt
PKI-587
PKI-402
Class I phosphatidylinositol 3-kinases (PI3Ks) play a key role in
the biology of human cancer.1 PI3Ks are divided into three classes
(I–III) based on their structures, mode of regulation, and substrate
the development of inflammatory and autoimmune diseases. More
than 50% of all solid tumors have gene mutations, deletions, or
amplifications that lead to upregulated PI3K/Akt/mTOR signaling.1
Therefore, blocking the PI3K/Akt/mTOR signaling pathway by
inhibiting both PI3K lipid and mTOR serine/threonine kinase activ-
ity provides an innovative strategy for cancer therapy. Dual PI3K/
mTOR inhibitors such as PKI-4025 and PKI-5874 inhibit all p110
isoforms, as well as mTORC1 and mTORC2.2 These molecules effec-
tively block PI3K/Akt/mTOR signaling in cancers with mutations in
PIK3CA and PIK3R1, PTEN loss, and RTK-dependent activation.2
Dual PI3K/mTOR inhibitors also mitigate the feedback activation
of PI3K signaling caused by selective mTORC1 inhibitors (i.e., rap-
amycin and its analogs), and because of this they may yield greater
therapeutic benefit in cancer patients.2 The strong antiproliferative
activities of dual PI3K/mTOR inhibitors have already been demon-
strated by the highly efficacious compounds, PKI-402 and PKI-587,
shown in Figure 1, and others.3 Here we describe a novel series, the
2-oxatriazines, which exhibited similar potency to PKI-402 and
PKI-587 and good metabolic stability.
preference.1 Class IA PI3Ks are comprised of three isoforms (p110
a,
p110b and p110d) that have a common regulatory subunit (p85),
and are primarily activated by signals from receptor tyrosine ki-
nases (RTKs). The class IB PI3K (p110c) is structurally similar,
but it has a different regulatory subunit (p101), and it is exclusively
activated by G-protein coupled receptors.
PI3Ks phosphorylate the 30-OH position of the inositol ring of the
membrane phospholipid, phosphatidylinositol-bisphosphate(4,5)
(PIP2), to form the phosphatidylinositol-triphosphate(4,5,6) PIP3.
PIP3 recruits pleckstrin homology domain containing proteins, such
as PDK1 and Akt, to the inner cell surface where PDK1 phosphory-
lates and actiavtes Akt,1 which in turn leads to mTOR activation.
mTOR, a PI3K related kinase (PIKK) family member, is a component
of the mTORC1 and mTORC2 serine/threonine kinase complexes,
which play key roles in cell homeostasis and growth, and are abnor-
mally regulated in tumor cells.
Aberrant activation of the PI3K signaling cascade stimulates cell
growth, survival, proliferation, and migration. These events not
only promote the formation of malignant tumors, but also enhance
Compounds14 and 25 are recently reported dual pan-PI3K /mTOR
inhibitors that utilize the morpholine oxygen for the key hinge re-
gion hydrogen bonding interaction in the ATP pocket of both class
I PI3Ks and mTOR. Analog 1 is a bismorpholinotriazine, and since
only one morpholino group is needed for binding to the PI3K hinge
region, the second morpholine of 1 can be replaced with other
groups to further optimize compound properties and biological
⇑
Corresponding author.
E-mail addresses: christoph.dehnhardt@pfizer.com, christophd@me.com (C.M.
Dehnhardt).
0960-894X/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.06.063

4774
C. M. Dehnhardt et al. / Bioorg. Med. Chem. Lett. 21 (2011) 4773–4778
O
N
O
N
N
N
O
N
N
N
O
N
N
N
O
N
N
O
N
O
N
N
H
N
H
N
N
H
N
H
1(PKI-587)
2(PKI-402)
O
N
N
N
O
O
N
O
N
O
N
N
H
N
H
3
Figure 1. 1(PKI-587) and 2(PKI-402) are recently reported dual PI3K/mTOR inhibitors. Compound 3 is a novel dual pan-PI3K/mTOR inhibitor which has an efficacy profile
comparable to that of 1 and 2.
profiles. Many triazine inhibitors have been disclosed in the recent
literature,6 while 2-oxatriazine-based PI3K inhibitors provided nov-
elty due to their rare use as kinase-inhibitors. Thus, we synthesized7
2-oxatriazines to generate a back-up series for 1. First, we wanted to
enhance the potency of this scaffold utilizing previously known SAR
information, such as the introduction of benzamido ureas. This effort
culminated in the discovery of 3, a compound which showed an
in vitro and in vivo potency profile similar to that of 2, particularly
in regard to in vivo biomarkersuppression. In this publicationwe de-
scribe the SAR studies leading to 3.
tion, compounds 8–13 showed good microsomal stability in
various species, except for 9 and 12 which showed only moderate
stability in rat microsomes. Tumor cell growth inhibition by the
methoxy analogues 8–13 was not as potent as that found for com-
pounds 1 or 2. Analogue 9, the best compound in this subset, still
showed a more than twofold lower potency against MDA-MB-
361 and PC3-cells compared to compound 1.
Replacing the methoxy group with an isopropoxy group led to
compounds 15–18, which in general exhibited good potency
against PI3K
ative to methoxy analogues 8–13. For example, compound 17
exhibited no selectivity for PI3K /mTOR, while compound 9
showed 19-fold selectivity. Compound 9 also showed better PI3K
a and mTOR, but lower selectivity for PI3Ka/mTOR rel-
The synthesis of oxatriazines 8–24 is shown in Scheme 1. Cyan-
uric chloride 4 was aminated with morpholine at 0 °C to give the
1,3-dichloro-5-morpholino triazine 5, which was reacted with
the appropriate lithiumalkanolate to give 6a–e.
a
a
potency than 17. However, compound 17 showed better tumor cell
growth inhibition then 9. Analogue 17 was overall the most potent
i-PrO substituted derivative in enzyme and tumor growth inhibi-
tion, and showed moderate solubility at physiological pH as well
as good stability against rat, nude mouse, and human microsomes.
Introducing the more bulky O-tropinyl group in 24 led to good en-
Subsequently, 6a–e were converted to anilines 7a–e by reaction
with 4-aminophenylboronic acid pinacolester under Suzuki condi-
tions. Compounds 7a–e were condensed with the appropriate 4-
aminobenzamide analogues 9a–d under triphosgene activation to
obtain ureidobenzamides 3, 8–24. For SAR purposes, we were also
interested in keto tautomers of 2-oxatriazines, such as 27. The syn-
thesis of 27 is shown in Scheme 2. Dichlorotriazine 5 was treated
with 1 N NaOH at room temperature to give 25, which was coupled
with 26 under Suzuki conditions to give 27. The structure of 27 was
determined by 2D NMR indicating that 28 is the major tautomer in
DMSO solution.
zyme potency against PI3Ka and mTOR but low cell potency. It is
not clear if this result has to do with the physical properties such
as the high tPSA (=146) of 24. However, in other series10,11we also
observed relatively low cell potency for compounds carrying a ba-
sic nitrogen in a similar region of the molecule.
The unsubstituted oxatriazine 27 showed moderate potency
against PI3Ka, strong selectivity for PI3Ka/mTOR (>100-fold), and
All final compounds were tested for inhibition5 of PI3K
a, PI3Kc,
and mTOR kinase activity. Due to the compelling efficacy profile of
14,8,9 and the fact that compounds 1 and 2 show no oral bioavail-
ability, we were interested in an iv administered compound.
Hence, we limited our pharmaceutical profiling to relevant data
such as solubility at pH 7.4, and to stability studies in rat, nude
mouse, and human liver microsomes to mimic hepatic clearance.
The physical properties and biological data for analogues 3, 8–24
and 27 are shown in Table 1.
weak cell potency. Following 2D NMR studies we could show that
27 predominantly exist as triazine-one tautomer carrying the H at
N-5. The steric clash of the 5-H with the morpholine 3-CH2 could
lead to a slight rotation of the morpholine out of plane which could
lower its ability to bind to Val851 in the hinge region, resulting in
lower potency against PI3Ka. The mTOR selectivity may be ex-
plained by a similar phenomenon with regard to the 6-aryl-
appendage. Here, the 5-H could lead to a slight rotation around
the aryl group. Rotation around the C-2 aryl C–C bond has already
Initially the effect of a small substituent such as the methoxy
group (8–13) at the 2-position of the triazine core was evaluated.
been reported to give a rise in selectivity for PI3K
ies. For example, Sutherlin et al.12 showed that 2-methyl-5amino-
pyrimidines show 100-fold selectivity of PI3K /mTOR compared
the non methyl-substituted analog. In their case this observation
was rationalized based on X-ray co-crystal with PI3K and docking
in a mTOR homology models showing that the methyl group
a over mTOR ser-
These analogues showed good potency (IC50 <3 nM) against PI3K
with moderate selectivity over PI3K and mTOR. In fact, some
methoxy substituted compounds (9–13) showed between 9- and
29-fold selectivity between PI3K and mTOR. Furthermore, deriv-
atives 8–13 exhibited good aqueous solubility at pH 7.4. In addi-
a,
c
a
a
c

C. M. Dehnhardt et al. / Bioorg. Med. Chem. Lett. 21 (2011) 4773–4778
4775
O
N
O
N
O
N
Cl
a)
c)
b)
N
N
N
N
N
N
N
N
R1
R1
Cl
N
Cl
Cl
N
Cl
O
N
Cl
O
N
4
6a-e
5
7a-e
NH2
O
O
d)
H2N
NR2
9a-d
N
N
N
O
R1
O
N
O
NR2
8-24
N
H
N
H
a) NEt3, morpholine, 0 oC, 92%, b) R1OH, BuLi, THF c) (Ph3P)4Pd, 4-aminophenylboronic acid pinacol ester, Na2CO3,
9a-d
DME, 140 oC,1h, µW; d) triphosgene, NEt3,
.
17, R1 = Oi-Pr, NR2 = -NMe-(CH2)2-NMe2
8, R1 = OMe, NR2 = -NH-(CH2)2-1-piperidine
9, R1 = OMe, NR2 = -NMe-(CH2)2-NMe2
10,R1 = OMe, NR2 = -NH-(CH2)2-NMe2
11, R1= OMe, NR2 = -NMe-(CH2)2-NHMe
12, R1= OMe, NR2 = 4-methylpiperazine
13, R1 = OMe, NR2 = 3,3-dimethylpiperazine
18, R1 = O Pr, NR2 = -NH-(CH2)2-NMe2
i-
3, R1 = O-3-(S)-tetrahydrofuranyl, NR2 = -NMe-(CH2)2-NMe2
19, R1 = O-3-(S)-tetrahydrofuranyl, NR2 = 4-Me2N-piperidine
20, R1 = O-3-(S)-tetrahydrofuranyl, NR2 = -NH-(CH2)2-1-piperidine
21, R1 = O-3-(S)-tetrahydrofuranyl, NR2 = -NH-(CH2)2-1-pyrrolidine
22, R1= O-3-(S)-tetrahydrofuranyl, NR2
= 4-methylpiperazine
14, R1 = 3-oxetanyloxy, NR2 = 4-methylpiperazine
15, R1 = Oi-Pr, NR2 = 4-methylpiperazine
23, R1 = O-3-(S)-tetrahydrofuranyl, NR2 = 4-Me2N-piperidine
24, R1 = O-tropinyl, NR2 = NH2
16, R1 = Oi-Pr, NR2 = 4-NH-1-methylpiperidine
Scheme 1. General synthetic route to 2-oxatriazines 3, 8–24.
O
B
O
O
O
N
O
N
O
O
N
N
N
N
H
N
H
N
NH
O
a)
b)
26
N
N
N
NH
Cl
O
N
O
N
Cl
N
Cl
O
N
25
N
N
H
N
H
27
5
a) 1N NaOH/THF(1:1), rt (64%); b) Na2CO3, DME, 140 oC, 1h µW (23%).
Scheme 2.
twisted the the aryl group out of plane due to a steric clash of the
methyl group with Tyr867 in mTOR. Now, the methyl is oriented
toward a region where residue differences between PI3K and
mTOR exist. A similar phenomen could play a role for compound
24 just that here it is a steric clash between H–N and CH.
Introduction, of a 3-oxyoxetanyl group in 2-position led to com-
pound 14. Analogue 14 and the i-Pr analogue 15 exhibited very
similar profiles in cell proliferation assays. However, 14 showed
also showed excellent potency against PI3Ka 4
best knowledge this effect is not caused by an interaction with
amino acid residues in the ATP- binding pocket of PI3K . Hence,
we decided to use ligand based design to look for groups that mi-
mic the molecular shape of the 2-position morpholine group of 1 as
the second triazine substituent. Several analogues with 2-substitu-
ents were modeled and overlayed with compound 1. In this study,
the 2-(S)-oxytetrathydofuryl group of 3 showed an almost perfect
overlap with the second morpholine in 1. Figure 2 shows an over-
. However, to our
a
better potency against PI3K
relative to 15. The introduction of hydrogen bond acceptors such
as the O in the oxetane led to increased potency against PI3K
a, and lower potency against mTOR,
lay of 1 and 3 docked in a PI3K
a homology model. As modeling
a
.
suggests, the morpholine and 3-oxy-THF group occupy the same
space, thus allowing identical binding of the morpholine oxygen
to Val851, the urea O with Lys802, and the NH with Asp810, which
In addition, other compounds such as 1 carrying an O-containing
morpholine, where the oxygen roughly occupies the same region,

4776
C. M. Dehnhardt et al. / Bioorg. Med. Chem. Lett. 21 (2011) 4773–4778
Table 1
Biological data and physical properties for 2-oxatriazine analogues 3, 8–24, and 27
a
c
Compound
IC50 (nM)
mTOR
Solubilityb @pH 7.4
t1/2 (min)
PI3K
a
PI3K
c
MDA-361d
PC3e
Human
N. Mouse
Rat
8
9
2.0
0.4
0.6
0.8
1.2
1.4
0.6
3.0
1.4
1.0
3.0
0.2
1.0
1.4
1.4
1.7
1.4
3.2
15
20.5
7.0
10.5
9.5
13.5
4.0
9.5
49.5
22.0
18.0
24.5
4.8
6.5
8.0
6.0
14.3
7.2
72.5
96.5
11
8.2
7.7
5.6
14.5
22.5
18.5
3.0
1.3
1.3
0.3
0.4
0.7
1.1
0.4
0.3
1.7
1.2
5.3
1200
0.4
2
<31
15
<31
110
35
30
4
5
<30
5
11
3
4
5
8
69
34
71
374
91
111
32
33
52
13
41
9
24
18
27
21
11
>100
>100
>100
>100
3
61
4
0
4
15
3
>100
>100
1
23
1
>30
>30
>30
>30
>30
>30
ND
>30
>30
>30
>30
>30
18
>30
>30
>30
>30
>30
>30
ND
>30
>30
23
>30
>30
>30
>30
>30
>30
>30
ND
>30
15
>30
>30
16
29
>30
17
10
11
12
13
14
15
16
17
18
3
19
20
21
22
23
24
27
1
19
>30
>30
27
>30
27
28
20
16
4
>30
>30
15
6
4
10
29
2917
>1000
3
4453
>1000
11
62
ND
15
0
ND
ND
>30
>30
ND
>30
>30
>30
>30
15
0.4
1
2
9
8
21
a
b
c
The values are an average of at least two separate determinations with a typical variation of less than 30%.
g/mL].
Half-life of drug when incubated for 30 min with liver microsomes of the species shown.
Breast cancer cell line.
Prostate cancer cell line.
[l
d
e
profile (IC50 values: PI3Ka, enzyme, 0.2 nM; MDA-MB-361 and
PC3 tumor cell lines, 3 and 9 nM, respectively), paired with high
solubility and good stability in rat, nude, mouse, and human micro-
somes. Hence, compound 3 was chosen for an in vivo side by side
comparison with our clinical candidate 1.
Compounds 1 and 3 were administered at 10 and 25 mg/kg in
mice bearing MDA-MB-361 xenografts. Figure 3 shows that both
compounds 1 and 3, given at 25 mg/kg (iv), suppressed phosphor-
ylated p-Akt-T308, p-Akt-S473, p-p70S6K, and p-S6 (p-Akt-S473,
p-p70S6K, and p-S6 are mTOR specific biomarkers5 and p-Akt-
T308 is consistent with their in vitro profiles. Both 1 and 3 not
only suppressed these PI3K/mTOR biomarkers for at least 8 h,
but they also induced cleaved poly-adenosine-diphosphate-ribose
polymerase (cPARP), a marker for cells undergoing apoptosis.14
However, this study showed that 3 had a somewhat less profound
biological effect on PI3K and mTOR specific biomarkers than our
clinical candidate 1. In fact, compound
3 administered at
25 mg/kg, achieved similar biomarker suppression to that ob-
served with analog 1 given at 10 mg/kg. Furthermore, compound
3 displayed a much stronger biomarker response than previously
reported for our first preclinical candidate 2.9 For example, com-
pound 3 showed 8 h activation of cPARP when 25 pmk were
dosed, while 2 showed cPARP induction only at higher dose
(50 mpk). Clearly further investigation of 3 needs to be conducted
to discover the full potential of this compound.
Figure 2. Overlay of compound
(magenta carbons, ball-and-stick representation) docked in a PI3K
model. Residues that form critical hydrogen bonding interactions are shown with
orange carbons such as binding of morpholine to the hinge region Val851 and the
urea oxygen to Lys802 and urea hydrogen to Asp810.
1
(cyan carbons, stick representation) and
3
a
homology
In summary, we introduced a novel 2-oxatriazine scaffold that
was optimized using ligand based design and modeling. Novel
analogues based on this 2-oxatriazine scaffold showed good po-
tency against PI3Ka and mTOR, and good potency in tumor cell
(MDA-MB-361[breast], PC3 [prostate]) growth inhibition assays.
Compound 3 showed an in vitro profile superior to that of pre-
clinical candidate 2 and comparable to clinical candidate 1. Fur-
thermore, in vivo biomarker studies showed that compound 3
was more potent than compound 2, but not quite as potent as
1. More result from our ongoing optimization effort of 3 will be
reported in due course.
is consistent with their very similar enzyme potencies. Based on
this modeling13 we designed and synthesized novel analogues,
where binding features to the hinge region as well as the aryl ure-
ido-group interactions remained unchanged.
Indeed, compounds 3, 19–23 showed good potency against
PI3Ka and excellent potency in tumor cell growth inhibition as-
says. Among these analogues, 3 showed the best in vitro potency

C. M. Dehnhardt et al. / Bioorg. Med. Chem. Lett. 21 (2011) 4773–4778
4777
Figure 3. In vivo biomarker analysis at 8 h after compounds 1 and 3 were administered at 10 and 25 mg/kg (iv) to MDA-MB-361 tumor bearing nude mice.
was quenched with sat. NH4Cl solution and extracted with ether (3 ꢁ 20 mL).
The combined fractions were dried over MgSO4. After filtration of MgSO4, the
mixture was concentrated and purified by flash chromatography using Isco-
combiflash eluting with EtOAc:Hex (1:1). The combined product fractions were
distilled to dryness to give 2.8 g (46%) of the product as a white solid.
1H NMR (CDCl3) d 5.51 (m, 1H), 4.06 (m, 1H), 4.00–3.81 (m, 7H), 3.73 (m, 4H),
2.19 (m, 2H) ppm. MS (ESI) m/z 287.1.
Acknowledgments
The authors thank Dr. Joseph Ashcroft for advanced 2D NMR
experiments and the Pearl River Chemical Technologies group for
their support.
To a microwave vial was added 6d (S)-4-(4-chloro-6-(tetrahydrofuran-3-yloxy)-
1,3,5-triazin-2-yl)morpholine (1 g, 3.49 mmol), 4-(4,4,5,5-tetramethyl-1,3,2-
dioxaborolan-2-yl)aniline (1.146 g, 5.23 mmol), Na2CO3 aq 2 M (3.49 ml,
6.98 mmol), Pd(Ph3P)4 (0.403 g, 0.349 mmol) and DME (10 ml) and the
mixture was heated for 1 h to 140 °C in a microwave oven. After completion,
the reaction mixture was filtered. The filtrate was evaporated and purified by
flash chromatography using Isco-combiflash eluting with EtOAc:Hex (1:1). The
combined product fractions were distilled to dryness to give 665 mg (of the
product. as beige solid.
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1H NMR (CDCl3) d: 8.24 (d, J = 8.6 Hz, 2H), 6.90 (d, J = 8.6 Hz, 2H), 5.61 (m, 1H),
4.30 (m, 1H), 4.04–3.73 (m, 11H), 2.26 (m, 2H), 1.57 (m, 2H) ppm.
MS (ESI) m/z 344.2.
To a stirred solution of triphosgene (0.373 mg, 1.258
(20 ml) was added 7d (S)-4-(4-morpholino-6-(tetrahydrofuran-3-yloxy)-1,3,5-
triazin-2-yl)aniline (1.200 mg, 2.097 mol) at 25 °C. The reaction mixture was
lmol) in anhydr. THF
l
stirred for 5 min and NEt3 (45 mL, 0.33 mmol) were added and the reaction
mixture was stirred for additional 1 h. Then 9a 4-amino-N-(2-
(dimethylamino)ethyl)-N-methylbenzamide (1.392 mg, 6.29 lmol) was added
and stirred for another 0.5 h and NEt3 (406 mL, 2.91 mmol) was added and the
mixture was stirred over night. The solvents were removed in a N2 stream and
the crude mixture was purified by semi-prep-HPLC to obtain 3 as an off white
solid (665 mg, 53%). 1H NMR (DMSO) d: 9.11 (s, 1H), 8.97 (s, 1H), 8.29 (d,
J = 8.9 Hz, 2H), 7.59 (d, J = 8.9 Hz, 2H), 7.51 (d, J = 8.6 Hz, 2H), 7.33 (d, J = 8.6 Hz,
2H), 5.59 (m, 1H), 4.00–3.68 (m, 12H), 3.40 (m, 2H), 2.95 (s, 3H0, 2.40 9 m, 2H),
2.30–2.07 (m, 8H) ppm.
MS (ESI) m/z 591.3 Analytical LC using Prodigy ODS3 column, ACN/H2O eluent at
1 mL/min flow (containing 0.05% TFA), 20 min. gradient 5% ACN to 95% ACN,
monitored by UV absorption at 215 nm showed 99.4% purity.
8. Mallon, R. G.; Feldberg, L. R.; Lucas, J.; Chaudhary, I.; Dehnhardt, C.; Delos
Santos, E.; Chen, Z.; dos Santos, O.; Ayral-Kaloustian, S.; Venkatesan, A.;
Hollander, I. Clin. Cancer Res. 2011, 17, 3193.
9. Mallon, R.; Hollander, I.; Feldberg, L. L.; Lucas, J.; Gibbons, J.; Venkatesan, A. M.;
Dehnhardt, C. M.; Delos Santos, E.; Chen, Z.; dos Santos, O.; Ayral-Kaloustian, S.;
Brooijmanns, S.; Soloveva, V. Mol. Cancer Ther. 2010, 9, 976.
10. Dehnhardt, C. M.; Venkatesan, A. M.; Chen, Z.; Delos Santos, E.; Santos, O.;
Bursavich, M.; Brooijmans, B.; Mallon, R.; Hollander, I.; Feldberg, L. Lucas, J.; Yu,
K. Ayral-Kaloustian, S.; Gibbons, J.; Abraham, R.; Mansour T. S. Novel
Imidazolopyrimidines as Dual PI3-Kinase/mTor Inhibitors Proceedings of the
100th Annual Meeting of the American Association for Cancer Research; 2009
Apr 18–22; Denver, CO; AACR; 2009; Abstract nr 2017.
11. Venkatesan, A. M.; Dehnhardt, C. M.; Chen, Z.; Delos Santos, E.; Dos Santos, O.;
Bursavich, M.; Gilbert, A. M.; Ellingboe, J. W.; Ayral-Kaloustian, S.; Khafizova,
G.; Brooijmans, N.; Mallon, R.; Hollander, I.; Feldberg, L.; Lucas, J.; Yu, K.;
Gibbons, J.; Abraham, R.; Mansour, T. S. Bioorg. Med. Chem. Lett. 2010, 20, 653.
12. Sutherlin, D. P.; Sampath, D.; Berry, M.; Castanedo, G.; Chang, Z.; Chuckowree,
I.; Dotson, J.; Folkes, A.; Friedman, L.; Goldsmith, R.; Heffron, T.; Lee, L.; Lesnick,
J.; Lewis, C.; Mathieu, S.; Nonomiya, J.; Olivero, A.; Pang, J.; Prior, W. W.;
4. Venkatesan, A. M.; Dehnhardt, C. M.; Delos Santos, E.; Dos Santos, O.; Ayral-
Kaloustian, S.; Khafizova, G.; Brooijmans, N.; Mallon, R.; Hollander, I.; Feldberg,
L.; Lucas, J.; Yu, K.; Gibbons, J.; Abraham, R. T.; Chaudhary, I.; Mansour, T. S. J.
Med. Chem. 2010, 53, 2636.
5. Dehnhardt, C. M.; Venkatesan, A. M.; Delos Santos, E.; Chen, Z.; Santos, O.;
Ayral-Kaloustian, S.; Brooijmans, N.; Mallon, R.; Hollander, I.; Feldberg, L.;
Lucas, J.; Chaudhary, I.; Yu, K.; Gibbons, J.; Abraham, R.; Mansour, T. S. J. Med.
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I.; Mansour, T. S. Bioorg Med. Chem. Lett. 2010, 20, 5869.
7. Synthesis
of
(S)-N-(2-(dimethylamino)ethyl)-N-methyl-4-(3-(4-(4-
morpholino-6-((tetrahydrofuran-3-yl)oxy)-1,3,5-triazin-2-
yl)phenyl)ureido)benzamide 3: A solution of (S)-tetrahydrofuran-3-ol (1.874 g,
21.27 mmol) in THF (32 mL) was cooled to ꢀ78 °C and n-butyl lithium in
hexanes (11.06 ml, 27.7 mmol) was slowly added. The mixture was stirred for
0.5 h and a solution of 5 4-(4,6-dichloro-1,3,5-triazin-2-yl)morpholine (5 g,
21.27 mmol) in THF (16 mL) was added. Stirring was continued for 2 h at
ꢀ78 °C and the mixture was allowed to warm to 22 °C overnight. The reaction

4778
C. M. Dehnhardt et al. / Bioorg. Med. Chem. Lett. 21 (2011) 4773–4778
Salphati, L.; Sideris, S.; Tian, Q.; Tsui, V.; Wan, N. C.; Wang, S.; Wiesmann, C.;
Wong, S.; Zhu, B.-Y. J. Med. Chem. 2010, 53, 1086.
Zhang, W.; Hollander, I.; gibbons, J. J.; Abraham, R. T.; Ayral-Kaloustian, S.;
Mansour, T. S.; Yu, K. J. Med. Chem. 2009, 52, 5013.
13. Zask, A.; Verheijen, J. C.; Curran, K.; Kaplan, J.; Richard, D. J.; Nowak, P.;
Malwitz, D. J.; Brooijmans, N.; Bard, J.; Svenson, K.; Lucas, J.; Toral-Barza, L.;
14. Golas, J. M.; Arndt, K.; Etienne, C.; Lucas, J.; Nardin, D.; Gibbons, J.; Frost, P.; Ye,
F.; Boschelli, D. H.; Boschelli, F. Cancer Res. 2003, 63, 375.