Discovery of imidazo[1,2-b]pyridazines as IKKβ inhibitors. Part 2: Improvement of potency in vitro and in vivo

Article abstract of DOI:10.1016/j.bmcl.2010.12.078

We have increased the potency of imidazo[1,2-b]pyridazine derivatives as IKKβ inhibitors with two strategies. One is to enhance the activity in cell-based assay by adjusting the polarity of molecules to improve permeability. Another is to increase the affinity for IKKβ by the introduction of additional substituents based on the hypothesis derived from an interaction model study. These improved compounds showed inhibitory activity of TNFα production in mice.

Full text of DOI:10.1016/j.bmcl.2010.12.078

Bioorganic & Medicinal Chemistry Letters 21 (2011) 904–908
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Discovery of imidazo[1,2-b]pyridazines as IKKb inhibitors.
Part 2: Improvement of potency in vitro and in vivo
⇑
Hiroki Shimizu , Isao Yasumatsu, Tomoaki Hamada, Yoshiyuki Yoneda, Tomonori Yamasaki, Shinji Tanaka,
Tadashi Toki, Mika Yokoyama, Kaoru Morishita, Shin Iimura
R&D Division, Daiichi Sankyo Co., Ltd, 1-16-13 Kitakasai, Edogawa-ku, Tokyo 134-8630, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
We have increased the potency of imidazo[1,2-b]pyridazine derivatives as IKKb inhibitors with two
strategies. One is to enhance the activity in cell-based assay by adjusting the polarity of molecules to
improve permeability. Another is to increase the affinity for IKKb by the introduction of additional
substituents based on the hypothesis derived from an interaction model study. These improved
Received 30 September 2010
Revised 12 December 2010
Accepted 16 December 2010
Available online 21 December 2010
compounds showed inhibitory activity of TNF
a
production in mice.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
IKK
NF-jB
TNFa
Inhibitor
Interaction model
Nuclear factor-
j
B (NF-
j
B) is a transcription factor that has a
lead compounds that showed potent IKKb inhibitory activities
and high selectivity against other kinases13,14 (Fig. 1). In the follow-
ing step, it becomes important to find the compounds that show
strong activity in vivo to develop an anti-inflammatory agent.
crucial part in the immune system.1,2 NF-
jB plays a number of
important roles such as immune-response, inflammation, cell pro-
liferation, survival and cell death by regulating the expression of a
variety of genes of proteins including pro-inflammatory cytokines
Therefore, we started inhibition assay of TNF
a production by
(e.g., TNF
sion molecules, osteoclastogenesis-related factors and inducible
proteins.3–7 NF-
B is implicated in the pathogenesis of multiple
inflammatory diseases and autoimmune diseases including rheu-
a
, IL-1, IL-6), chemokines, anti-apoptotic proteins, adhe-
mouse whole blood cell as a cell-based assay to connect cell-free
assay and in vivo assay in mice. The results are shown in Table 1.
j
matoid arthritis. It is observed that NF-
jB is highly active in the
site of inflammation.3–5,8
H
H
N
N
There are some signal transduction cascades for the activation of
NF-
B.6d,9 In the classical (canonical) pathway, known as one of the
major pathways, IKK complex (IKK /IKKb/NEMO) plays an impor-
tant role in activating NF-
B (RelA/p50).9,10 RelA/p50 exists in an
inactive complex associated with I B. The phosphorylation of I
by the IKK complex and subsequent K48-linked polyubiquitination
lead to the degradation of I B. The released RelA/p50 promotes tran-
N
N
j
N
N
N
N
a
R1
N
j
H
(
)
j
jB
N
n
CH3
O
N
O
N
H
j
H3C
scription of genes of pro-inflammatory cytokines and other induc-
ible proteins in nucleus. Of the IKK components, IKKb is essential
1 (n=1)
IKKβ: IC50 = 0.055 μM
TNFα: IC50 = 0.69 μM (THP-1 cell)
3 (R1= H)
IKKβ IC50 = 0.20 μM
TNFα: IC50 = 0.69 μM
in phosphorylation of IjB. It is anticipated that a potent IKKb inhib-
itor could be a promising anti-inflammatory agent.2a,11,12
Hence, we continued our effort to acquire orally available small
molecules that would be potent IKKb inhibitory agents. We have
reported imidazo[1,2-b]pyridazine derivatives 1, 2 and 3 as the
2 (n=2)
IKKβ: IC50 = 0.047 μM
TNFα: IC50 = 1.5 μM
4 (R1= Me)
IKKβ IC50 = 0.33 μM
TNFα: IC50 = 2.4 μM
Figure 1. Imidazo[1,2-b]pyridazine derivatives that were discovered as the lead
compounds for the development of IKKb inhibitors.13
⇑
Corresponding author. Tel.: +81 3 3680 0151; fax: +81 3 5696 8609.
E-mail address: shimizu.hiroki.hu@daiichisankyo.co.jp (H. Shimizu).
0960-894X/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2010.12.078

H. Shimizu et al. / Bioorg. Med. Chem. Lett. 21 (2011) 904–908
905
Table 1
In vitro activity, in vivo activity and physicochemical data of imidazo[1,2-b]pyridazine derivatives
H
N
N
N
N
R2 R3
R4
N
N
H
O
Compds
R2
H
R3
H
R4
H
IKKba IC50
(l
M)
TNF
a
PAMPAc
Inhibition of
TNF (%)
Plasma levele
at 30 mg/kg
po (lg/ml)
Metabolic
productionb
(Pe  10À6 cm/s)
(pH7.4)
a
stabilityf
(%)
IC50
(l
M)
at 30 mg/kg
po in miced
1
3
0.055
0.20
6.8
0.80
2.1
2.7
1.2
0.57
1.9
0.48
0.23
0.17
0.40
<2
No inhibition
10
0.0075
0.39
—
—
—
—
—
0.34
0.15
0.16
—
77
71
—
—
—
—
—
50
33
33
—
Structure, see Figure 1.
OMe
H
F
H
H
H
H
H
>50
6.5
<2
—
36
6.1
>50
42
>50
>50
g
5a
5b
5c
5d
6
7a
7b
7c
7d
H
OMe
H
F
H
F
F
F
F
H
H
H
H
Me
Me
Et
n-Pr
Bn
0.023
0.071
0.021
0.022
0.097
0.042
0.018
0.016
0.012
—
—
—
—
—
26
32
52
—
H
7e
H
F
0.017
0.59
>50
40
0.12
7
*
Cl
Cl
7f
H
F
0.017
1.2
39
61
0.45
28
*
7g
7h
7i
H
H
H
H
F
F
F
F
Cinnamyl
Ph
CH2CO2H
CH2CH2OH
0.013
7.3
0.11
0.015
0.95
—
3.9
0.68
>50
—
14
15
—
—
—
—
—
—
—
—
—
—
—
—
7j
O
7k
7l
H
H
F
F
0.017
0.015
>10
2.7
<2
<2
—
—
—
—
—
—
OH
*
*
H
N
O
a
b
c
d
e
f
The method is described in Ref. 13.
Mouse whole blood cell. The method is described in Ref. 17.
Parallel artificial membrane permeability assay. Median of three tests.
The method is described in Ref. 18.
Plasma concentrations of test compounds at 90 min after oral administration.
Remaining rate of test compounds (1
Not tested.
lM) after 30 min of incubation with mouse liver microsomes (0.1 mg/ml).
g
It was revealed that 1 showed decreased activity in this assay.
Furthermore, a plasma level of 1 was found to be very low after
oral administration in mice.
To overcome these problems and further enhancement of po-
tency, we developed two strategies. One is to adjust the polarity
of cyclic secondary amines to improve permeability. Another is
to enhance affinity of the compounds for IKKb by the introduction
of additional substituents.
The latter strategy came from the hypothesis that the introduc-
tion of an appropriate moiety to the amide nitrogen on the substi-
tuent of the 3-position of imidazo[1,2-b]pyridazine could increase
affinity for IKKb from the interaction model study.13
To begin with, we put the first strategy into practice. We intro-
duced electron-withdrawing substituents such as the methoxy
group or fluorine on the pyrrolidine ring to decrease the basicity
and adjust the polarity.
About the former strategy, we considered the permeability of 1 to
be too low to penetrate the cellular membrane of mouse whole
blood cell. The poor permeability made it difficult to show oral
absorption. In our previous paper, we have reported that the PAMPA
values of the compounds with pyrrolidine substructure are low.13
The high polarity of the pyrrolidine unit seemed to cause poor per-
meability. On the other hand, we have found that the secondary
amine moiety is important in showing strong IKKb inhibitory activ-
ity and the interaction model study followed these results.13 Based
on these findings, we decided to decrease polarity by maintaining
the secondary amine structure.
In compounds 5a, 5c and 5d, inhibitory activities in cell-free as-
say were twofold more potent than that of 1.15 Also, these com-
pounds showed over threefold more active in cell-based TNF
a
inhibitory assay. In particular, cell-based activity of 5d was en-
hanced more than 10-fold compared with 1. These results could
be explained by the improvement of permeability. As indicated
in the PAMPA value, the permeability of 5d was improved by the
adjustment of polarity by the introduction of fluorine to the appro-
priate site on pyrrolidine16 (Table 1).
About the latter strategy, it was hypothesized that a hydrophobic
pocket emerges as a result of the conformational shift of the

906
H. Shimizu et al. / Bioorg. Med. Chem. Lett. 21 (2011) 904–908
Lys44
N
a
Glu97
Helix C
Hinge
O
H
NH3+
O
O
Glu61
N
O
Cys99
N
O
H
N
O
O
H
N
Asp166
N
Leu167
O
O
Activation loop
Glu97
H
N
b
N
O
Glu61
O
O
Cys99
N
Lys44
N
N+H
H
H
H
O
N
O
O
N
N
N
O
NH3+
O
HN
O
Asp166
N
Val29
Leu21
NH
O
Leu167
Figure 2. 2D representations of the ATP binding site of IKKb. (a) Before the
interaction with inhibitors. Side chain of Leu167 occupies the hydrophobic pocket
(represented as a red line). (b) The predicted binding mode of compound 1 with
IKKb. The hydrogen bondings are represented as orange dotted lines. Van der Waals
interactions are represented as yellow lines. The pocket that is revealed by the
movement of the activation loop is located in the direction of amide nitrogen to
hydrogen (shown by a magenta arrow).
activation loop.13 Before the interaction with inhibitors, the pocket
is occupied by the side chain of Leu167 on the activation loop
(Fig. 2a). The revealed pocket is considered to exist in the direction
of the N–H bond of amide on the substituent of the 3-position of
imidazo[1,2-b]pyridazine (Fig. 2b). There are only a few investiga-
tions about the conformational shift of the activation loop including
the DLG motif, but not DFG19; therefore, we approached this hypoth-
esis by synthesizing the compounds. We observed that compound 4
in which the amide nitrogen was methylated, shows IKKb inhibitory
activity.13 We began searching for the substituents that suit the
pocket and increase affinity for IKKb.
Figure 3. Predictive binding mode of 7g with IKKb. (a) Top view (from the
N-terminated domain). Cinnamyl moiety on the amide nitrogen in the 3-position is
directed to the hydrophobic pocket. Imidazo[1,2-b]pyridazine moiety interacts with
the hinge region. Ammonium salt of pyrrolidine interacts with Glu61 and Asp166.
(b) Side view. The pocket is suited with cinnamyl moiety. There is permissibility in
the back of the pocket. Cyclopropylmethyl moiety is caught among Leu21, Val29
and Leu167.13
We evaluated 6, 7a–7l, the combination of the amide N-alkyl/
aryl moiety and pyrrolidine/(4R)-fluoropyrrolidine unit.
The results are shown in Table 1. The inhibitory potencies of 6
for 1 and 7a20 for 5d in cell-free assay were decreased to about half,
whereas those in cell-based assays were increased because the
permeability of 6 and that of 7a were improved.
maintains interactions in the hinge region and with carboxylate
residues.
The compounds with hydrophobic substituents on the amide
In the inhibition assay of LPS-induced TNF
a production in mice,
nitrogen 7b–7g showed potent IKKb inhibitory activity and TNF
a
7f showed 61% inhibition of TNF production and 7c showed 52%
a
production inhibitory activity, while the compound with polar
substituent 7i exhibited decreased potency.
inhibition by an oral dose of 30 mg/kg, whereas 7a showed 26%
inhibition and 3 showed 10% inhibition (Table 1). These results
indicate that the modifications from the two strategies are effec-
tive for exhibiting inhibitory activity in vivo. Compound 7f showed
potent inhibitory activity in vivo despite moderate levels of inhib-
itory activity in cell-based assay. This could be explained in part by
the high level in plasma.
The test compounds were synthesized as shown in Scheme 1
and Scheme 2. (3S)-Fluoropyrrolidine 11c was prepared from
3-hydroxyproline derivative 8. The reduction of methyl ester gave
primary alcohol, which was protected as benzyloxymethyl (BOM)
ether. The (3S)-hydroxyl group on the pyrrolidine ring was
converted to (3R)-isomer 9 by Mitsunobu reaction. Compound 9
led to (3S)-fluoride 1021 followed by cleavage of the BOM group
to afford 11c. The hydroxyl groups of 11a–11d22 were converted
Compounds 7k and 7l showed strong IKKb inhibitory activity,
but cell-based activities were reduced because of poor permeabil-
ity as indicated in the PAMPA values. N-Phenyl derivative 7h also
showed decreased IKKb inhibitory activity. It is assumed that the
phenyl group crashes into the entrance of the pocket. At minimum
ethyl group, which is about the size of the substituent on the amide
nitrogen, seems to be required for the interaction with the en-
trance of the pocket. For the back of the pocket, various (small or
large, hydrophobic or hydrophilic) substituents were allowed.
Compound 7j that has a hydroxyethyl group also showed potent
IKKb inhibitory activity.
The considered binding mode is shown in Figure 3. The pocket
is occupied by the additional substituent, and the compound also

H. Shimizu et al. / Bioorg. Med. Chem. Lett. 21 (2011) 904–908
907
a-c
Boc
N
HO
O
HO
BOMO
N
N
Boc
H
Boc
N
N
O
N
a,b
N
9
N
8
N
N
Br
17
d
F
e
F
OH
N
Boc
N
O
18
BOMO
HO
Boc
11c
10
H
N
c,d
or
e,f
f,g
or
h-j
R3
N
R3
N
N
R2
H2N
N
R2
HO
R2 R3
R4
N
Boc
Boc
N
12a R2:OMe, R3:H
12b R2:H, R3:OMe
12c R2:F, R3:H
11a R2:OMe, R3:H
11b R2:H, R3:OMe
11c R2:F, R3:H
N
H
O
5a-5d, 6
12d R2:H, R3:F
11d R2:H, R3 :F
Boc
N
H
N
g,i
k-m
H3C
N
or
h,i
N
N
N
N
Boc
N
H2N
Boc
N
N
N
H
14
13
R4
F
F
H
N
CH3
NH
N
CH3
O
O
N
N
O
O
NH
H
Boc
n
19
7a-7k
+
12d
F
N
H
CHO
H
N
Boc
H
N
N
15
16
N
j,k
N
N
N
H
N
N
N
CH3
Scheme 1. Syntheses of pyrrolidine derivatives. Reagents and conditions: (a) LiBH4,
THF 0 °C to rt, 94%; (b) BOMCl, DIPEA, 0 °C to rt, CH2Cl2 79%; (c) HCO2H, DIAD, Ph3P,
THF, reflux then 1 N NaOH aq, THF-MeOH, rt, 75%; (d) Deoxo-FluorÒ, CH2Cl2, À78 °C
to rt, 35%; (e) H2, Pd/C, MeOH; (f) DPPA, DIAD, Ph3P, THF; (g) Ph3P, THF, H2O (quant.
2 steps for 12a, 46% 2 steps from 12b); (h) MsCl, Et3N, CH2Cl2; (i) NaN3, DMF,
50–60 °C; (j) H2, 5% Pd/C, EtOH (43% 4 steps for 12c, 62% 3 steps for 12d); (k) TFAA,
Et3N, CH2Cl2, 81%; (l) MeI, NaH, DMF, 79%; (m) K2CO3, MeOH, 88%; (n) NaBH3CN,
AcOH, MeOH, 36%. Boc: tert-Butyloxycarbonyl, BOM: Benzyloxymethyl.
O
F
OH
N
O
O
N
H
20
7l
Scheme 2. The combination of imidazo[1,2-b]pyridazine scaffold and pyrrolidine
units. Reagents and conditions: (a) (Boc)2O, DMAP, CH2Cl2, 93%; (b)
4-(dihydroxyboryl)benzoic acid, Pd(PPh3)2Cl2, K2CO3, 1,4-dioxane-water (3:2),
77%; (c) 12a, 12b, 12c, 12d or 14 DMT-MM, DMF; (d) TFA, CH2Cl2 (74% 2 steps
for 5a, 23% 2 steps for 5b, 20% 2 steps for 5c, 94% 2 steps for 5d via 19); (e) 14,
EDCÁHCl, HOBt, Et3N, 92%; (f) 4 N HCl in dioxane, 96%.; (g) R4X (MeI, EtI, n-PrI, BnBr,
1-chloro-3-(chloromethyl)benzene, 1-chloro-4-(chloromethyl)benzene, cinnamyl
bromide, t-butyl chloroacetate, 4-chloromethylbenzoic acid or 1-[(2-iodoeth-
oxy)methyl]-4-methoxybenzene), NaH, DMF; (h) PhI, CuI, K2CO3, DMF, 150 °C; (i)
TFA, CH2Cl2, 71% 2 steps for 7a, 39% 2 steps for 7b, 35% 2 steps for 7c, 69% 2 steps for
7d, 43% 2 steps for 7e, 44% 2 steps for 7f, 18% 2 steps for 7g, 14% 2 steps for 7h, 32%
2 steps for 7i (to cleave Boc groups and t-Bu ester), 40% 2 steps for 7j (to cleave Boc
groups and the PMB group), 18% 2 steps for 7k; (j) 16, DMT-MM, DMAP, Et3N, DMF
71%; (k) TFA, CH2Cl2, 76%. PMB: p-methoxybenzyl.
to primary amines 12a–12d via the azide moiety. Pyrrolidine
derivative 14 was synthesized by methylation of 13 by way of
trifluoroacetamide. Benzylamine derivative 16 was prepared by
reductive amination of aldehyde 15 with 12d (Scheme 1).
Compounds 5a–5d, 6 and 7l were synthesized by the condensa-
tion reaction of carboxylic acid 18 or 2013 and amines 12a, 12b,
12c, 12d or 16 followed by the cleavage of the Boc group.23
Compounds 7a–7k were prepared by alkylation of amide
nitrogen of compound 19 by various alkyl halides followed by
the cleavage of protective groups. 1-[(2-Iodoethoxy)methyl]-4-
methoxybenzene was prepared as indicated in a previous report.24
N-Phenyl derivative 7h was formed by coupling with iodobenzene
(Scheme 2).
In conclusion, we have discovered potent compounds by the
modification of the substituents in the 3-position of imidazo[1,2-
b]pyridazine derivatives based on two strategies.
One strategy is the introduction of an electron-withdrawing
group on the pyrrolidine ring to adjust polarity for better perme-
ability. Another is the introduction of hydrophobic substituents
to the amide nitrogen to improve affinity for IKKb. We believe that
these substituents interact with the pocket which is newly made
after the activation loop moving out.
Acknowledgements
We are grateful to the member of Drug Metabolism & Pharma-
cokinetics Research Laboratories for the measurement and valida-
tion of physicochemical data.
References and notes
1. Sen, R.; Baltimore, D. Cell 1986, 47, 921.
2. (a) Li, Q.; Verma, I. M. Nat. Rev. Immunol. 2002, 2, 725; (b) Hayden, M. S.; Ghosh,
S. Cell 2008, 132, 344.
3. Brown, K. D.; Claudio, E.; Siebenlist, U. Arthritis Res. Ther. 2008, 10, 1.
4. Viatour, P.; Merville, M. P.; Bours, V.; Chariot, A. Trends Biochem. Sci. 2005, 30,
43.
5. Senftleben, U.; Karin, M. Crit. Care Med. 2002, 30, S18.
6. (a) Karin, M.; Lin, A. Nat. Immunol. 2002, 3, 221; (b) Coussens, L. M.; Werb,
Z. Nature 2002, 420, 860; (c) Kim, H. J.; Hawke, N.; Baldwin, A. S. Cell Death
Differ. 2006, 13, 738; (d) Perkins, N. D.; Gilmore, T. D. Cell Death Differ.
2006, 13, 759.
We have acquired orally active compounds such as 7c and 7f
that showed increased IKKb inhibitory activities and TNFa produc-
tion inhibitory activities in mice. Further investigation of IKKb
inhibitors will be reported in the near future.

908
H. Shimizu et al. / Bioorg. Med. Chem. Lett. 21 (2011) 904–908
7. (a) Asagiri, M.; Takayanagi, H. Bone 2007, 40, 251; (b) Ruocco, M. G.; Maeda, S.;
leukocyte density of 2.5 Â 105 cells/ml. Test compounds at various
Park, J.-M.; Lawrence, T.; Hsu, L.-C.; Cao, Y.; Schett, G.; Wagner, E. F.; Karin, M. J.
Exp. Med. 2005, 201, 1677.
8. Tak, P. P.; Firestein, G. S. J. Clin. Invest. 2001, 107, 7.
9. (a) Hayden, M. S.; Ghosh, S. Genes Dev. 2004, 18, 2195; (b) Häcker, H.; Karin, M.
Sci. STKE 2006, 357, re13.
10. (a) DiDonato, J. A.; Hayakawa, M.; Rothwarf, D. M.; Zandi, E.; Karin, M. Nature
1997, 388, 548; (b) Mercurio, F.; Zhu, H.; Murray, B. W.; Shevchenko, A.;
Bennett, B. L.; Li, J.; Young, D. B.; Barbosa, M.; Mann, M.; Manning, A.; Rao, A.
Science 1997, 278, 860; (c) Woronicz, J. D.; Gao, X.; Cao, Z.; Rothe, M.; Goeddel,
D. V. Science 1997, 278, 866.
11. Karin, M.; Yamamoto, Y.; Wang, Q. M. Nat. Rev. Drug Discovery 2004, 3, 17.
12. (a) Blake, S. M.; Swift, B. A. Curr. Opin. Pharmacol. 2004, 4, 276; (b) Burke, J. R.;
Strnad, J. Trends Pharmacol. Sci. 2007, 28, 142.
concentrations or 5% DMSO were predispensed as 20 ll aliquots into 96-well
plates. After the addition of 160
10 g/ml LPS or RPMI-1640 medium was added. After incubation for 4 h at
37 °C in 5% CO2, plasma was obtained by centrifugation (2000 rpm, 5 min,
4 °C). TNF concentration in the plasma was measured by ELISA assay as
described by the manufacturer’s instructions (BD Bioscience).
18. Inhibition assay of LPS-induced TNF production in mice.
ll of cell suspension to the plate, 20 ll of
l
a
a
Male BALB/c mice (7–12 weeks old) were orally given a test compound or 0.5%
methyl cellulose. Thirty min after treatment, 0.02 mg/kg of LPS in saline was
administrated intravenously. One hour after the injection of LPS solution, blood
was collected from inferior vena cava with heparin as an anticoagulant under
ether anesthesia. Plasma was obtained by centrifugation (3000 rpm, 30 min,
4 °C) and immediately stored at À20 °C. TNF
a concentration in the plasma was
measured by ELISA assay as described by the manufacturer’s instructions (R&D
Systems).
13. Shimizu, H.; Tanaka, S.; Toki, T.; Yasumatsu, I.; Akimoto, T.; Morishita, K.;
Yamasaki, T.; Yasukochi, T.; Iimura, S. Bioorg. Med. Chem. Lett. 2010, 20, 5113.
14. Compound 1 showed more than 90% inhibition against three kinases (ALK,
19. Degterev, A.; Hitomi, J.; Germscheid, M.; Ch’en, I. L.; Korkina, O.; Teng, X.;
Abbott, D.; Cuny, G. D.; Yuan, C.; Wagner, G.; Hedrick, S. M.; Gerber, S. A.;
Lugovskoy, A.; Yuan, J. Nat. Chem. Biol. 2008, 4, 313.
JAK2 and PKD2), and showed 80–90% inhibition against 6 kinases at 10
of 250 kinases.
lM out
15. Compound 5d showed 80% inhibition against PKD3 at 0.2
l
M out of 19 kinases
20. Compound 7a showed 61% inhibition against PKD3 at 0.2 lM out of 19 kinases
in which compound 1 showed relatively strong inhibitory activity.
16. The difference between the PSA values of 5c (88.3 Å2) and 5d (82.6 Å2) was
noted. The 3D structures were generated using CORINA (Molecular Networks
GmbH) and optimized using MacroModel and PM3 method in the MOPAC 7
program. PSA values were calculated using VEGA.
in which compound 1 showed relatively strong inhibitory activity.
21. Lal, G. S.; Pez, G. P.; Pesaresi, R. J.; Prozonic, F. M.; Cheng, H. J. Org. Chem. 1999,
64, 7048.
22. Machinaga, N.; Chiba, J.; Hoh, H.; Nakayama, A.; Muro, F.; Yoneda, Y.; Iimura, S.
WO2007069635, 2007.
17. Inhibition assay of LPS-induced TNF production by mouse whole blood cell.
Whole blood was collected from the inferior vena cava of BALB/c mice and
23. Kunishima, M.; Kawachi, C.; Iwasaki, F.; Terao, K.; Tani, S. Tetrahedron Lett.
1999, 40, 5327.
heparinized. The blood was suspended in RPMI-1640 medium to
a
final
24. Herb, C.; Bayer, A.; Maier, M. E. Chem. Eur. J. 2004, 10, 5649.