Discovery of Potent and Selective A2A Antagonists with Efficacy in Animal Models of Parkinson's Disease and Depression

Article abstract of DOI:10.1021/acsmedchemlett.7b00175

Adenosine A_2A receptor (A_2AAdoR) antagonism is a nondopaminergic approach to Parkinson's disease treatment that is under development. Earlier we had reported the therapeutic potential of 7-methoxy-4-morpholino-benzothiazole derivativ

Full text of DOI:10.1021/acsmedchemlett.7b00175

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Letter
Discovery of Potent and Selective A2A Antagonists with Efficacy
in Animal Models of Parkinson’s Disease and Depression.
Sujay Basu, Dinesh Barawkar, Vidya Ramdas, Minakshi Naykodi, Yogesh Shejul, Meena
Patel, Sachin Thorat, Anil Panmand, K. Kashinath, Rajesh Bonagiri, Vandna Prasad,
Ganesh Bhat, Azfar Quraishi, Sumit Chaudhary, Amol Magdum, Ashwinkumar V Meru,
Indraneel Ghosh, Ravi Bhamidipati, Amol Raje, Vamsi Madgula, Siddhartha De, Sreekanth
Rouduri, Venkata Palle, Anita Chugh, NARAYANAN HARIHARAN, and Kasim A Mookhtiar
ACS Med. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acsmedchemlett.7b00175 • Publication Date (Web): 05 Jul 2017
Downloaded from http://pubs.acs.org on July 6, 2017
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Discovery of Potent and Selective A2A Antagonists with Efficacy in
Animal Models of Parkinson’s Disease and Depression.
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Sujay Basu*, Dinesh A. Barawkar, Vidya Ramdas, Minakshi Naykodi, Yogesh D. Shejul, Meena Patel,
Sachin Thorat, Anil Panmand, K. Kashinath, Rajesh Bonagiri, Vandna Prasad, Ganesh Bhat, Azfar
Quraishi, Sumit Chaudhary, Amol Magdum, Ashwinkumar V. Meru, Indraneel Ghosh, Ravi K. Bhaꢀ
midipati, Amol A. Raje, Vamsi L. M. Madgula, Siddhartha De, Sreekanth R. Rouduri, Venkata P. Palle,
Anita Chugh, Narayanan Hariharan, Kasim A. Mookhtiar.
Advinus Therapeutics Ltd., Drug Discovery Facility, Quantum Towers, Plotꢀ9, PhaseꢀI, Rajiv Gandhi Infotech Park, Hinꢀ
jawadi, Pune 411 057, India
KEYWORDS: Parkinson’s disease; Adenosine receptors; Rat liver microsomes; Pharmacokinetics.
ABSTRACT: Adenosine A2A receptor (A2AAdoR) antagonism is a nondopaminergic approach to Parkinson’s disease treatment
that is under development. Earlier we had reported the therapeutic potential of 7ꢀmethoxyꢀ4ꢀmorpholinoꢀbenzothiazole derivatives
as A2AAdoR antagonist. We herein described a novel series of [1,2,4]triazolo[5,1ꢀf]purinꢀ2ꢀone derivatives that display functional
antagonism of the A2A receptor with high degree of selectivity over A1, A2B and A3 receptors. Compounds from this new scaffold
resulted to discovery of highly potent, selective, stable and moderate brain penetrating compound 33. Compound 33 endowed with
satisfactory in vitro and in vivo pharmacokinetics properties. Compound 33 demonstrated robust oral efficacies in two commonly
used models of Parkinson’s disease (haloperidolꢀinduced catalepsy and 6ꢀOHDA lesioned rat models) and depression (TST and
FST
mice
model).
Parkinson’s disease (PD) is a progressive neurodegenerative
trials and beyond. A2AAdoR antagonists are classified as xanꢀ
thine and nonꢀxanthine derivatives. Among xanthine derivaꢀ
tives, Istradefylline (KWꢀ6002, Kyowa Hakko Kirin Co Ltd.),
with moderate receptor selectivity was launched in Japan for
PD.8 Several classes of nonꢀxanthine A2AAdoR antagonists
have been known in the literature and they are either monocyꢀ
clic, bicyclic or tricyclic coreꢀbased antagonists.9ꢀ16 In our preꢀ
ceding publication we have reported a series of novel nonꢀ
xanthine compounds with moderate oral in vivo efficacy in 6ꢀ
OHDA lesioned rat model of PD.17 Based on these data, we
have focused on identifying a new scaffold with high affinity,
selective and robust orally efficacious antagonist of the
A2AAdoR. Here, we report discovery and structureꢀactivity
relationship (SAR) studies on a novel structural class of 5ꢀ
aminoꢀ[1,2,4]triazolo[5,1ꢀf]purinꢀ2ꢀone (9ꢀ33, scheme 1) deꢀ
rivatives of high affinity, potency and selective A2AAdoR anꢀ
tagonist with robust oral efficacy in an in vivo model of PD
and depression without dyskinesia.
movement disorder affecting approximately 1% population
over the age of 65.1 The number of patients affected by PD is
expected to double by 2030 due to an aging population and
increased life expectancy.2 Adenosine A2A receptor
(A2AAdoR) is a highly distributed receptor in the central nervꢀ
ous system and is expressed at high levels in the nigrostriatum.
A2AAdoR are predominantly located in the spiny neurons of
striatum3, where they are coꢀexpressed with dopamine D2
receptors on GABAergic neurons on the indirect striatopallidal
pathway.4ꢀ5 Inhibition of the striatopallidal neurons by
A2AAdoR antagonism likely reduces motor deficits caused by
dopamine deficiency in PD. Unfortunately, current dopamine
replacement therapies for PD suffer from poor long term conꢀ
trol and undesirable side effects, mainly dyskinesia (involunꢀ
tary movements). Positive findings with A2AAdoR antagonists
have been observed in animal models of PD, ranging from the
reversal of haloperidolꢀinduced catalepsy in rodent and more
disease relevant models like 6ꢀhydroxydopamine (6ꢀOHDA)
lesioned rats models, MPTPꢀlesioned primates.6 PD patients
also have high prevalence of depression and current PD theraꢀ
pies do not treat depressive symptoms. A2AAdoR knockout
mice displayed reduction of immobility in functional assays in
vivo, such as tail suspension and (TST) forced swim tests
(FST) which are predictive of clinical antidepressant activity.7
Thus interest in the use of A2AAdoR antagonists in PD has
increased because it might improve over existing PD agents in
the treatment of nonmotor PD symptoms like depression as
well as improves motor function without causing dyskinesia.
Numerous A2AAdoR antagonists have reached phase I clinical
Synthesis of the fused tricyclic core 7 began with the comꢀ
mercially
available
4,6ꢀdichloropyrimidineꢀ2,5ꢀdiamine
(Scheme 1). The compound 1 treated with ethanol amine and
followed by cyclisation and Nꢀ1 methylation afforded comꢀ
pound 4. Reaction of 4 with hydrazine gave intermediate 5
which on reaction with appropriate acid derivatives provided
6aꢀb. Dehydrative cyclization of 6aꢀb with N,Oꢀ
bis(trimethylsilyl)acetamide (BSA) gave compound 7aꢀb.
Reaction of compound 7aꢀb with pꢀtoluene sulphonyl chloride
yielded compound 8aꢀb. Amination of 8aꢀb with appropriate
aryl piperazine yielded compounds 9ꢀ33.
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Scheme 1. Synthesis of 9ꢀ33a
ed subꢀnanomolar functional potency in human with Ki 0.27
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3
4
5
6
7
8
nM. Replacement of phenyl with other heterocyles like pyriꢀ
dine (28ꢀ29), thiazole (30) and benzoxazole (31) retained
binding affinity (Ki in the range of 0.4ꢀ4.5 nM) and functional
potency (hKi in the range of 0.4ꢀ0.9 nM) for A2AAdoR and
selectivity over A1AdoR. In general, the compounds described
here were found to be metabolically stable (data given in supꢀ
plementary information, Table S1) in rat liver microsoms
(RLM) and human liver microsoms (HLM).
iii
i
ii
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2
3
4
Next, we focused our attention towards replacement of Cꢀ8
furanyl moiety with thiazole (32ꢀ33) and both compounds
retained binding affinity (hA2A Ki = 6.4 and 1.5 nM, respecꢀ
tively) and functional potency (hA2A Ki = 1.2 and 0.4 nM, reꢀ
spectively; rA2A Ki = 11.1 and 4.4 nM, respectively). Gratifyꢀ
ingly, compound 33 was >1100ꢀfold selective for A2AAdoR
over A1AdoR and >3000ꢀfold selective over A2B and A3AdoR
(Tableꢀ2). It also possessed high aqueous solubility at acidic
pH and good solubility at pH 7.4 (>2000 µM, 486 µM and 17
µM at pH 2.1, 4 and 7.4, respectively).
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6a-b
5
7a-b
R2
vii
viii
9-31
8a-b
9-33
32-33
To identify a lead, compound 33 was shortlisted for further
profiling as it achieved our predetermined targets for affinity,
potency, selectivity, metabolic stability and solubility.
a
o
Reagents and conditions: (i) Ethanol amine, EtOH, 100ꢀ110 C,
28 h; (ii) 4ꢀnitrophenyl chloro formate, K2CO3, CH3CN, rt, 24 h;
(iii) MeI, CH3CN, K2CO3, 60 °C, 16 h; (iv) NH2NH2.H2O, EtOH,
100ꢀ110 °C, 16 h; (v) R2ꢀCOOH, EDCI, HOBt, NMM, DMF, rt, 3
h; (vi) BSA, HMDS, 140ꢀ150 °C, 14 h; (vii) pꢀToluenesulfonyl
chloride, pyridine, rt, 24 h; (viii) R1 = aryl piperazine, DIPEA,
DMF, 80 °C, 16 h.
In vitro pharmacology and in vitro DMPK (drug metabolism
and pharmacokinetics)17 profiles of compound 33 have been
summarized in Table 2 and 3. Compounds 33 exhibited high
binding and functional selectivity in human A2AAdoR over A1,
A2B and A3AdoR in in vitro assays (Table 2). Compound 33
(Table 3) displayed good metabolic stability in mouse, rat, dog
and human liver microsomes and no significant inhibition of
the major CYP450 enzymes, 3A4,1A2, 2C9, 2C19, 2D6 (IC50:
>10 µM), and no blocking of hERG channel was observed at
the concentrations tested. No potential induction was observed
in cytochrome P450 assay. In addition, it was not cytototoxic
to HepG2 cells. It was moderately bound in mouse, rat, dog
and human plasma. It demonstrated high Cacoꢀ2 permeability
(both active and passive) and was not a substrate for PGP drug
efflux transporter. The in vivo pharmacokinetic (PK) properꢀ
ties of 33 was evaluated in rat, is summarized in Table 3.
Compound 33 exhibited high systemic plasma clearance in rat
with elimination halfꢀlife 1.0 h. Moderate volume of distribuꢀ
tion was observed. In oral PK, it exhibited rapid absorption
(Tmax: ≤1 h). Moderate plasma concentration (AUC (0ꢀt h)
(µM.h) = 2.2) was observed for this compound. Compound 33
displayed 32% oral bioavailability in suspension formulation.
When tested for brain distribution study in rat, (IV, 3 mpk) 33
showed moderate brain penetration with brain to plasma AUC
(0ꢀ4h) ratio of 0.38.
A series of substituted aryl piperazines (9ꢀ33, Tableꢀ1) were
synthesized and evaluated in in vitro assay as described in our
earlier communication.17ꢀ18 Our initial SAR study was focused
on to impart high affinity to A2AAdoR on to this novel scafꢀ
fold. The majority of aryl piperazine derivatives, 9ꢀ33 exhibitꢀ
ed high human A2AAdoR (hA2A) binding affinity (Ki = 0.2ꢀ6.4
nM) with moderate to high selectivity over A1AdoR. All these
aryl piperazine derivatives showed extremely high selectivity
over A2BAdoR and A3AdoR. Irrespective of the nature of the
substitution most of the compounds retained A2AAdoR binding
affinity. Compounds featuring electron releasing groups such
as ꢀOMe, ꢀMe, cyclopropyloxy, and extended ether on phenyl
ring (9ꢀ22) showed subꢀnanomolar binding affinity with Ki in
the range of 0.2ꢀ2.0 nM for A2AAdoR. When tested in funcꢀ
tional assay, compound 9ꢀ22 exhibited subꢀnanomolar funcꢀ
tional potency for both in human (Ki = 0.06ꢀ1.5 nM) and rat
(rKi = 0.06ꢀ3.9 nM) A2AAdoR cAMP assay. Compound 13,
having extended ether at para position, showed excellent bindꢀ
ing selectivity over A1 (A1/A2A = 850 fold), A2B (A2B/A2A
>
3000 fold) and A3AdoR (A3/A2A > 2000 fold; A2B and A3 seꢀ
lectivity data given in supplementary information, Table S1).
It also showed excellent functional potency, both in human (Ki
= 0.42 nM) and rat (Ki = 0.28 nM) A2AAdoR cAMP assay.
Compound 13 showed moderate solubility at pH 7.4 (<6 µM).
Compounds 23ꢀ25 containing small electron withdrawing
groups like ꢀF, ꢀCN, on phenyl ring exhibited subꢀnanomolar
to single digit nanomolar binding affinity with Ki in the range
of 0.5ꢀ1.0 nM for A2AAdoR and retained excellent selectivity
over A1, A2B and A3AdoR. Compounds, 23ꢀ24 showed excelꢀ
lent functional potency in human (Ki = 0.07, 0.3 nM, respecꢀ
tively) A2AAdoR. To our delight, compound 24 was more than
8000ꢀfold selective for human A2AAdoR over A1, A2B and
A3AdoR but it showed poor solubility at pH 7.4 (<2 µM).
Compounds, 26ꢀ27 with larger electron withdrawing groups
such as ꢀOCHF2,ꢀCF3, retained binding affinity with Ki 1.9
and 3.1 nM respectively, for A2AAdoR. Compound 26 exhibitꢀ
In vivo Efficacy Study: Compound 33 was tested for efficaꢀ
cy in two in vivo rat models of PD i.e. haloperidolꢀinduced
catalepsy in rat and potentiation of levodopaꢀinduced contralaꢀ
teral rotations in 6ꢀOHDA (6ꢀhydroxydopamine) lesioned rats.
In haloperidolꢀinduced catalepsy in rat model (Figure 1A), 33
doseꢀdependently attenuated the cataleptic effects of haloperiꢀ
dol in 1, 2 and 4 h. Compound 33 (3 & 10 mg/kg, PO) showed
significant effect on 1, 2 & 4h in catalepsy model. These data
also suggest that, in this primary model the duration of action
for in vivo efficacy of 33 is at least 4 h following oral adminꢀ
istration (3 and 10 mg/kg) and ED50 is 4.49 mg/kg. Compound
33 was then evaluated for their ability to potentiate Lꢀdopa
induced rotational behavior in the 6ꢀOHDA lesioned rat (Figꢀ
ure 1B).17 Compound 33 dose dependently potentiated Lꢀ
DOPA induced contralateral rotations with ED50: 1.2 mg/kg,
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ACS Medicinal Chemistry Letters
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PO. Compound 33 (10 & 30 mg/kg, PO) post 60 min showed
1
2
3
4
5
6
7
8
significant effect on potentiation of LꢀDOPA induced contraꢀ
lateral rotations measured up to 2hr in 6ꢀOHDA lesioned rats
as compared with LꢀDOPA (4mg/kg, IP) alone (Figure1B).
Given the high prevalence of depression in PD patients, the
positive results in the FST and TST models of behavioral desꢀ
pair suggest the potential of A2AAdoR antagonists to dramatiꢀ
cally improve over existing PD agents in the treatment of
nonmotor PD symptoms. When compound 33 tested in mouse
model of FST (Figure 1C) and TST (Figure 1D), it significantꢀ
ly decreased immobility time. Compound 33 (0.3, 1, 3 & 10
mg/kg, PO) significantly decreased immobility time in FST
with ED50 5.29 mg/kg. In TST model, 33 (1, 3 & 10 mg/kg,
PO) significantly decreased immobility time with ED50 0.70
mg/kg. In animal models of Parkinson’s disease, compound 33
improves motor function without causing dyskinesia and, as
an adjunct to levodopa, it improves motor function without
worsening dyskinesia. Compound 33 (0.3ꢀ3 mg/kg) inhibited
LꢀDopaꢀinduced behavioral sensitization after repeated daily
administration, which suggests a reduced risk of the developꢀ
ment of dyskinesias (Figure 1E).
3.
4.
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In summary, substantial SAR was developed in a series of
5ꢀaminoꢀ[1,2,4]triazoloꢀ[5,1ꢀf]purinꢀ2ꢀone, A2AAdoR antagoꢀ
nists leading to identification of a lead compound 33. Comꢀ
pound 33 exhibited promising affinity, potency and high selecꢀ
tivity. It also demonstrated a number of positive attributes with
respect to in vitro DMPK perspectives. Compound 33 had
acceptable PK properties with 32% oral bioavailability in rats.
33 displayed oral efficacy in two in vivo models of Parkinson
diseases and depression. In 6ꢀOHDA lesioned rats, 33 disꢀ
played robust oral efficacy with ED50: 1.2 mg/kg, without dysꢀ
kinesia. Further development around this series is in progress.
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ASSOCIATED CONTENT
Supporting Information
Experimental procedures, analytical data for compounds 2ꢀ33,
selectivity data (for A1, A2B and A3AdoR), metabolic stability data
in HLM and RLM, protocol for catalepsy model, FST, TST.
AUTHOR INFORMATION
Corresponding Author
13. Zhou, G.; Aslanian, R.; Gallo, G.; Khan, T.; Kuang, R.; Puꢀ
rakkattle, B.; De, Ruiz M.; Stamford, A.; Ting, P.; Wu,
*Phone: +91 20 66539600; fax: +91 20 66539620.
Eꢀmail address: sujay.basu@advinus.com
H.; Wang, H.; Xiao, D.; Yu, T.; Zhang, Y.;
Mullins,
D.; Hodgson, R.; Discovery of aminoquinazoline derivatives as
human A(2A) adenosine receptor antagonists. Bioorg. Med.
Chem. Lett. 2016, 26, 1348ꢀ1354.
ACKNOWLEDGMENT
14. Burbiel, J. C.; Ghattas, W.; Küppers, P.; Köse, M.; Lacher, S.;
Herzner, A. M.; Kombu, R. S.; Akkinepally, R. R.; Hockemeyꢀ
er, J.; Müller, C.E. 2ꢀAmino[1,2,4]triazolo[1,5ꢀc]quinazolines
and Derived Novel Heterocycles: Syntheses and Structureꢀ
Activity Relationships of Potent Adenosine Receptor Antagoꢀ
nists. ChemMedChem 2016, 11, 1–16.
15. Baraldi, P. G.; Saponaro, G.; Aghazadeh, T. M.; Baraldi, S.;
Romagnoli, R.; Moorman, A. R.; Varani, K.; Borea, P. A.;
Preti, D. Pyrroloꢀ and pyrazoloꢀ[3,4ꢀe][1,2,4]triazolo[1,5ꢀ
c]pyrimidines as adenosine receptor antagonists. Bioorg. Med.
Chem. 2012, 20, 1046ꢀ59.
Authors are grateful to the senior management of the Advinus
Group for its support and encouragement. Analytical departments
are being acknowledged for their help during this work. Advinus
publication no. ADVꢀAꢀ041.
ABBREVIATIONS
EDCI, 1ꢀEthylꢀ3ꢀ(3ꢀdimethylaminopropyl)carbodiimide; HOBT,
Hydroxybenzotriazole; NMM, NꢀMethylmorpholine; HMDS,
Hexamethyldisilazane, (1ꢀmethylꢀ4ꢀphenylꢀ1,2,3,6ꢀ
tetrahydropyridine)
16.
Schering Corp (Neustadt, B.R.; Hao, J.; Liu, H.; Boyle, C.D.;
Chackalamannil, S.; Shah, U.G.; Stamford, A.; Harris, J.M.).
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tive, Orally Bioavailable Adenosine A2A Receptor Antagonists
and Their Biological Evaluation. J. Med. Chem. 2017, 60, 681ꢀ
694.
Shejul, Y.; Thorat, S.; Panmand. A. Fused Tricyclic Comꢀ
pounds as Adenosine Receptor Antagonist. USꢀ9006177B2,
April 14, 2015.
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2
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8
Table 1. In vitro profile of compounds 9ꢀ33
R2
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
9-31
9-33
32-33
% Inhibiꢀ
Functionꢀ
% Inhiꢀ
Functionꢀ
Binding
Ki (nM)
hA2A a
tion at 1
µM or
Ki (nM)
hA1a
Binding
Ki (nM)
hA2A a
bition at
1 µM or
Ki (nM)
hA1a
al
al
Cmpd
9
R1
Cmpd
22
R1
Ki (nM)
Ki (nM)
A2Ab
A2Ab
0. 21 (h)
0.58 (r)
1
58
0.3
56
0.26 (h)
0.07 (h)
1.1 (h)
0.74 (r)
1.4
0.4
0.3
2.0
45
45
1
32
5000 nM
50
10
11
12
13
23
24
25
26
0.06 (h)
0.06 (r)
0.3 (h)
1.15 (r)
0.6
0.5
1.9
F
N
50
0.25 (h)
0.4(h)
N
N
0.42 (h)
0.28 (r)
0.27 (h)
1.07 (r)
1700 nM
34
0.5 (h)
3.9 (r)
0.5
2.0
0.7
63
66
68
3.1
1.7
4.5
57
61
61
ND
14
15
16
27
28
29
0.4(h)
0.65(r)
ND
ND
ND
0.9
0.6
0.4
0.5
58
65
56
36
1.2 (h)
ND
1.2
0.4
6.4
1.5
58
48
0.9 (h)
17
18
19
20
30
31
32
33
0.15 (h)
0.05 (r)
1.5 (h)
0.42 (r)
1.2 ( h)
11.1 (r)
19
2.1 (h)
0.72 (r)
0.4 (h)
4.4 (r)
1700 nM
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0.22 (h)
21
1
2
3
4
5
NDꢀ not determind. NRꢀ no response at highest tested concentration 10 µM. aBinding affinities were determined by using membrane prepꢀ
arations from HEKꢀ293 cells overexpressing the relevant human AdoR isoform.17 All data points were evaluated in triplicates. For Ki deꢀ
termination, 8 concentrations IC50 curves were plotted. The functional activity of test compounds were determined using HTRF based
cAMP assay. Each compound was evaluated in triplicates at 12 concentrations. The mean Ki from two independent experiments (n=2) has
b
6
7
been reported.17
8
9
Table 2. Binding and functional selectivity profile of lead compound 33.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Binding Ki (nM)
Functional Ki (nM)b
Cmpd
33
hA2A
hA1
hA2B
hA3
hA2A
hA1
NR
hA2B
1.5
1700
5000
NR
0.4
<50% inhibition at 10µM
NRꢀ No inhibition observed at highest concentration 10 µM. b Evaluated at 12 concentrations, each data point in triplicates (n =
2). The mean Ki from two independent experiments has been reported.
Table 3: DMPK properties of lead compound 33a.
33 ( inꢀvitro Parameters)
33 ( inꢀvivo Parameters in Male Wistar Rats)
MR (nmol/min/mg) (MLM, RLM,
0.08, 0.00, 0.04, 0.14
Route of administration
iv
Po
DLM, HLM) @ 0.125 mg/mL protein
Solubility (µM) at pH 2.0, 4.0, 7.4
Cacoꢀ2 Permeability
>2000, 486, 17
Dose (mg/kg)
Cmax (µM)
3
10
AꢀB: 193, BꢀA:423
NA
0.6 ± 0.3
PPB (Mouse, Rat, Dog, Human)
CYP: 3A4,1A2, 2C9, 2C19, 2D6
51, 82, 78, 85
IC50: >10 µM
Tmax (h)
NA
0.8 ± 0.3
2.2 ± 0.7
NA
AUC0ꢀt (µM.h)
Vss (L/Kg)
3.6 ± 0.7
3.6 ± 0.7
45 ± 8
Cytotoxicity in HepG2 cell line
PXR induction
IC50: >30 µM
EC50: >60 µM
28%, 38%
CL (mL/min/Kg)
NA
hERG binding inhibition at 3, 10 µM
t
1/2(h)
1.0 ± 0.1
NA
NA
32
F (%)
aValues indicate mean for n = 4(rat) and vehicle: IVꢀ NMPꢀ10%, CrELꢀ10%, acetate buffer (pH 4.2) q.s; POꢀTween 80ꢀ1%, 0.5% w/v
NaCMC.17 NA: Not applicable
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D
1
150
125
100
75
2
3
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7
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9
*
50
*
*
25
*
*
0
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59
60
Naive
Vehicle
Compound 33 (0.3 mg/kg, PO)
Compound 33 (1 mg/kg, PO)
Compound 33 (3 mg/kg, PO)
Compound 33 (10 mg/kg, PO)
Preladenant (1 mg/kg, PO)
Desipramine (30mg/kg,PO)
Figure 1: (A) Effect of compound 33 on Haloperidol induced catalepsy in rats; (B) Effect of compound 33 on Potentiation of Levodopaꢀ
Induced contralateral Rotations in 6ꢀOHDA Lesioned Rats. *Significantly different as compared to LꢀDOPA, 4 mg/kg, IP alone group; (C)
Effect of compound 33 in Forced Swim Test (FST); (D) Effect of compound 33 Tail Suspension Test (TST) in mice; (E) Chronic effect of
Compound 33 in combination with LꢀDOPA or LꢀDOPA on Abnormal Involuntary Movements (AIMs; dyskinesia) in 6ꢀOHDA Lesioned
Rats. All data represent Mean ± SEM (n=6ꢀ7), * Significantly different as compared to Vehicle (* P<0.05); Vehicle: 0.5 % Tweenꢀ
80+0.5% CMC,q.s.).
For Table of Contents Use Only
Discovery of Potent and Selective A2A Antagonists with Efficacy in Animal Models of Parkinson’s
Disease and Depression.
Sujay Basu*, Dinesh A. Barawkar, Vidya Ramdas, Minakshi Naykodi, Yogesh D. Shejul, Meena Patel,
Sachin Thorat, Anil Panmand, K. Kashinath, Rajesh Bonagiri, Vandna Prasad, Ganesh Bhat, Azfar
Quraishi, Sumit Chaudhary, Amol Magdum, Ashwinkumar V. Meru, Indraneel Ghosh, Ravi K. Bhaꢀ
midipati, Amol A. Raje, Vamsi L. M. Madgula, Siddhartha De, Sreekanth R. Rouduri, Venkata P. Palle,
Anita Chugh, Narayanan Hariharan, Kasim A. Mookhtiar.
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1
2
NH2
N
N
S
N
3
4
5
6
7
8
9
N
N
O
N
N
O
O
N
N
F
33
= 1.5 nM
hA2A functional K = 0.4 nM
rA2A functional K = 0.44 nM
Binding Selectivity
/A2A = > 1100 fold
2B/A2A = >3000 fold
/A2A = >3000
Showed high functional selectivity over A
hA2A binding K
i
i
i
10
11
12
13
14
15
16
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A
A
A3
1
1
and A2BAdoR
ED50 (in 6-OHDA lesioned rat, po) = 1.2 mg/kg
Showed efficacy in depression model (FST and TST)
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