Development of angiotensin II antagonists with equipotent affinity for human AT1 and AT2 receptor subtypes.

Bioorganic & Medicinal ChemistryLetters, Vol. 4. NO. 19, pp. 2337-2342, 1994 Elsevia Science Ltd Printed in Great Britain 0960-894x/94

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0960-894X(94)00336-X

DEVELOPMENT OF ANGIOTENSIN

II ANTAGONISTS

WITH EQUIPOTENT AFFINITY FOR HUMAN ATI AND AT2

RECEPTOR SUBTYPES.

Tomasz W. Glinka’ $, Stephen E. de Laszlo*, Peter K. S. Siegl+, Raymond S. Chang+, Salah D. Kivlighn+, Terry S. &horn+, Kristie A. Faust+, Tsing-Bau Chent, Gloria J. Zingaro +, Victor J. Lotte+, William J. Greenlee. Deparhnent of &xploratoy Chemmisty, Merck Research LRborntories, PO Box 2000, Rnhway, New jersey 07@3, USA tDepurtment of Pharmacology, Merck Research Laboratones, West Point, Pennsylvania 19486, USA

Abstract.

The quinazolinone

(Ang II) to human

sulfonylcarbamate

ATI and AT2 receptors.

L-163,579 (9) is a potent, balanced This antagonist

produces

antagonist

a long-lasting

of the binding of angiotensin

blockade

of Ang II-induced

II

pressor

response in both rats and dogs after oral administration.

The continumg alternatives shown

efficacy

antagonists

in animal

in development

physiological expressed

high level of interest In angiotensin

to the well established models

of hypertension

11 (Ang II) antagomsts

ACE inhibitors.’

and some are currently

stages of development,

has remained

have shown that the plasma concentration

release of renin.l significance

is due to their therapeutic

The potenbal

potential

Several different classes of potent Ang II antagonists undergoing

are selective for the ATI receptor which has been determmed

effects of Ang IL3 The AT2 receptor, of unknown

at defined

antagonist)

antihypertensive

physiological

chnical

trials.2

to be responsible

as have

To date, Ang II for all the known

function, present in many tissues and selectively

unblocked. 3 Chnical trials of losartan

(an AT1 selective Ang II

of Ang II is increased ten fold due to the blocking of feedback inhibition

for increased concentrations

to lead to possible side effects has prompted

of Ang II m the presence of receptor subtypes of unknown the development

of antagonists

clinical

that bind to both the ATI and AT2

L159.689

6-Amino-2-alkyl-3-[(2’-(tetrazold-yl)biphen-4-yl~methylJ-quinazolinones ATI receptor5

and to antagonize

159,689.b Furthermore, affinity of compounds

can be modified to selectively antagonize

this structural

class may be modified

to provide AT2 selective binchng mhibitors.7

such as L-159,689 is largely derived from the presence of two lipophilic substituents

amino group,

and the presence

incorporation

of an acyl aminosulfonyl

absence of a disubstituted

the

the ATI receptor and bind with equal affinity to the AT2 receptor as shown above for L-

of a linear or non-linear

compounds

by L-162,393.8 The binding affmity ratios of angiotensin

to the 6-

three carbon alkyl group at C2. We have shown previously

or carbamoylaminosulfonyl

6-amino group provided

The AT2 binding attached

group m place of the 2’-tetrazole substituent with AT2/ATI

antngomsts 2337

IC50 ratios of approximately

that

and in the

10, as illustrated

were also assessed in rat and human adrenal tissue.9 The

2338

T. W. GLINKAet al.

binding affinity ratios in these tissues were generally class.

functional

response assay existed to determine

less than or equal to 1.0 in human fluoroQ’-acylaminosulfonyl-blphenyl

tissue.

increased although

on the structural

from 10 to 15. Since no in viva

provided

enhancement

class of Ang II antagonists

IC50 ratio was

with the the DuPont Merck group we had learnt that a 2of AT2 binding

group. I* We describe herein the incorporporation

acylaminosulfonyl-biphenyl group into the quinazolinone

increased

the extent of AT2 receptor blockade, our goal for the AT2/ATl

From our collaboration

group

the extent of the increase depended

2 the ratio of the A’Q/ATI I&

In the case of the acylaminosulfonamide

and the identification

affinity

over the 2-unsubstituted

2’.

of the 2-fluoro-2’-acylaminosulfonyl-biphenyl of L-163579 (9) as an antagonist

of the AT1

receptor that binds with equal affinity to the AT2 receptor.

v

R’CONH

v

Synthetic routes: A: a,b,c,d,f,g,h.; B: c,f,e,d,g,h.; C: c,f,e,d,h.; D: c,f,e,d,g,h.;E. c,f,e,d,g,h,i., F: e,d,c,f,h.; G : e,d,h,c,f. a. 4-bromo-2-fluorobenzylbromide/K2CO9/DMF ; b. 2-~SO2NHt-Bu~-Pl~B~OH~2/~Pl~3P~4Pd/toluene/ethanol/aq. H2 10% I’d/C

; d. TFA/anisole

or RlCOCI

or

COCl2

R3COCl/DMAP/pyridine;

; e. 4-bromomethyl-3-fluoro-2’-(t-butylam~nosulfonyl~-bipl~enyl

followed

by

i-Pr(Me)NH

1.heating m R3’OH (neat)

, g. heating

in morphohne

NaOH; c

(V)/K2C03/DMF ; f RINCO or iPr(Me)NH / pyridme, h

Development

The synthetic previously.8

methodology

yields

XIII

intermediate

or XIIIa

intermediates

alkylating

was accompanied

butylsulfonamide quinazolinone

by the O-alkylation

with trifluoracetic ureas by sequential

considerable

improvement

XIIIa was conveniently

Antagonists

treatment

over the previously

were evaluated

for binding

IV (

of the t-

of 6-IPrfMe)NCONH-

and isopropylmethylamine

of XIII was found to be considerably

of XIII leading to the transalkoxylated

to ATI and AT2 receptors

analogs

aorta IC5o AT2/ATt

reported

by comparing

analog

displayed

and shorter C-2 sidechain

in a variety

was a

more reactive

sulfonylcarbamate

with the same R’ but different

previously

(modeling

and NMR studies provided

publication).t2

of the series.

lC5o AT2/ATt

2 and 9,4

RI substituents

2’-N-benzoylaminosulfonyl

acidic function provided

the isobutoxyacetyl

use of a isobutoxyacetyl

antagonists

the most balanced

small

Within a series of 2-ethyl

affinities to the receptors

are found except for the

with improved

antagonist

of a This

ratios.

Introduction

was found to confer more AT2 potency

R3 group provided

(l-

Within the 2-ethyl

affinities were very similar, although

urea present in 16 and 17 and the pyridyl affinity.

was still

affinity Ang II antagonists.

and 16,5 and 14,3 and 10,3 and 20.

(9-13) similar binding

without compromising

improved,

ratios greater than 1.0. Only the combination

a variety of balanced

(7, 8,9) the binding

some

the human

with a 2-butyl or 2-propyl substituents

analog 11, the affinity of 11 for the ATI receptor being substantially The morpholine

Unfortunately,

of L-161,393 (Table 1, entry 11, although

(7-21) provided

the C-2 homologs

R3 groups

of species and tissues as

ratios of 1,3 and 4 (Table 1) were found to

in relative affinities to the receptor subtypes gave rise to changes in IC5o AT2/ATl

variation of R’ that may be introduced

antagonist

during the deprotection

one pot synthesis

= 1 vide supm). In general, antagonists

highly potent towards both receptors,

is illustrated

substituents,

intermediate

In both cases the Nalkylation

effect of the fluorine atom at the Z-position of the biphenyl was found to be

= 8.7 of the fluorinated

(desired value of IC5o AT2/ATl

isobutyloxymethylene members

to 2-(SO2NHt-Bu)-

( Scheme 1 step fJEa Other ureas were ( Scheme 1 step f.) or by transamination at elevated

of this fluorine effect and will be the subject of a separate

series with the same R3 group but differing

analogs

affinity

3-4 fold lower than the desfluoro

fluorine atom substitution

differences

with Suzuki coupling

for L-161,393

isocyanates

functionality

the variable I to biphenyl

I, or the more advanced

VIII with phosgene

reported method described

series. 10 The rat midbrain/rabbit

ratio IC50 AT2/ATl

observation

of the nitro group

III and VI in high yields.

and therefore the alcoholysis

However,

4-bromo-2-fluorotoluene

which was removed by acidolysis

carbamate

II to the Ang II antagonlsts

with 4-bromo-24uorobenzylbromIde

used in some cases ( Scheme 1 step 1.).

insight into the nature

6), although

incompatibility

of nitroquinarolinones

with the corresponding

displacement

effective in the quinazolinone

unsatisfactory

of II

to that described

from 2-alkyl-6-nitroquinazolinones

by coupling

of 6-aminoquinazolinone

in Table 1. The AT2 potency enhancing

be consistently

leading

quinazolinones

by-product,

( Scheme 1 step g.). The sulfonyl

towards such nucleophilic

2-alkyM-nltroquinazolinones

acid ( Scheme 1 step d.). The high yielding,

obtained either by direct condensation temperatures

Alkylation

the respective N-alkylated

was analogous

via Route A into several antagonists.‘l

routes

V was obtained

reagent

acid followed by NBS bromination.

Scheme 1 step e.) furnished

adrenal

of alternative

2339

antagonists

in Scheme 1. Suzuki coupling

which dld not suffer from the apparent

The biphenyl

phenylboronic

are outlined

the development

III or VI

conditions.

illustrated

quinazolinone

III fR3=Bu) which was then converted

of III prompted

product

to the fluorobiphenyl

II antagonists

The synthetic routes A-G leading from the corresponding

of general structure provided

applied

of angiotensin

less than that found for the other

amide in 18 illustrate

the considerable

of a 4-ethyl group into analogs bearing the

binding affinity (cf 13,14 and 15).13 Among R3

relative to ATt than any other type of sidechain.

The

6 in the P-propyl series and the most AT2 selective

in the L-ethyl series 11. It is worth noting that while 2-butyl and 2-propyl

substituted

antagonists

show higher

T. W. GLINKAet al.

2340

AT2/ATl

ratios in human adrenal

The sensitivity

than in rat adrenal,

of relative receptor

binding

analog L-163579 (9) was selected for in-depth ortro activity and receptors

promising

evaluation

pharmacological

were also determined

the situation in the 2-ethyl and 2-methyl substituted

affinity may reflect the known differences due to its balanced

properties

in prehminary

for 9 and the affinities

AT1=1.8nh4, AT2=1.7nMl and aorta (X50 ATr=4.lnM,

series is reversed.

primary

structure.t4

potency in the human adrenal,

in urvo testing.

were found to be balanced

AT2=5.lnM)

m receptor

IC50 values in other human

to both receptors

The

relatively high in

from kidney

tissue fIC50

tissue.

In viva Ach ‘v’15 Preliminary

in vim evaluation

most Interesting representative

of some of the fully balanced antagonists

of the series. It has shown, in its potassium

Ang II induced pressor response m both rats (1.0 mg/kg

US to select

shown in Table 1 allowed

9 as the

salt form, high iv. activity in the inhibition of the

iv. max. inhib. 91 f 3%, 6hr. mhib. 62 f 7%) and in dogs (1.0 mg/kg

iv:

max. inhi. 89 f 2%, 6hr inhib. 48~tl%).1~ 100

7

90 80 70 ._g .= P 2 .2

t+

60 50 40i’

30-

20-

//J

L-163,579

jF VP

lo-

-mm*---

rat

_-___c’-.

dog % inh, 37i9% at 24 hr

% mh,

no inhib at 24 hr

’ *I

0 -,-r-i’ -10.

,

.

0.0

)

,

,

1.0

2.0

.

,

.

30

,

.

4.0

,

.

,

.

60

5.0

,

Fig.1 Inhibition of AI1 challenge by 3 mg/kg dose of potassium salt of L-163,579 m conaous (n=2) and dogs (n=2) administered orally m 0.5 % methocel solution.

The EDso values determined

m rats were 0.29 and 0.76 mg/kg

and dogs L-163579 displayed

by AT1 radiohgand

163,579 bioequivalents

,

Time (hr)

normotensive

I v. and po admmistration

rats

respectively.

In both rats

binding assay).

were determrned

as

was found to be 23% m rats and 17% m dogs (AUC, concentration

In the absence of a functional response for blockade of the AT2 receptor L-

by ATland AT2 receptor bmdmg assay of plasma samples withdrawn

following po and iv dosing m rats and dogs. 16 The study confirmed that throughout

, ’ ’

potent, long lasting Ang II pressor response inhibitory activity when dosed orally at 3mg/kg

shown in Figure 1. At the same dose, 8 hr oral bioavailability measurement

followmg

.

7.0

in vwo

periodically

AT1 and AT2 bmdmg affinity was maintained

the experiment.

Conclusions Structural mcorporates

modification

sulfonylcarbamate

of L-162,393, a prototypical acidic functionahty

the human Ang II receptor subtypes. alkyl substituent

Incorporation

AT1 /AT2 balanced affimty qumazolinone

has led to considerable

improvement

m attaming

Ang II antagonist

balanced affinity towards

of a fluorine atom m the biphenyl moiety and truncation

resulted in a number of balanced Ang II antagomsts

with AT2/ATl

which

ICjo ratios =I or less.

of the 2-position

Development of angiotensin II antagonists

Table 1. In virm activities flC& - of bala&

auinazolinoneantaeonists

in rabbit,

2341

rat and human tissue Ane II -I

Rabbit ATlb

Rat adrenal

I

AT2

nm

nm

Human adrenald AT, AT2 nm nm ATz/ATT, s

1

BU

lPr(Me)N-

n-butoxy-

0.89

2.7

A

2

BU

3

BU

4

Pr

lPr(Me)N-

2-cyclopropylethoxy- 0.13

lPr(Me)N-

3-Me-butoxy-

0.23

O(CH,CH,),N- 3-Me-butoxy-

0.24

A

Pr

6

Pr

IP~NH-

2-F-4-Et-Ph-

0.20

iPrNH-

i-butyl-0-CH,-

0.52

7

Et

a

Et

9

Et

10

Et

EtNH-

2-cyclopropylethoxy- I 0.73

iPrNH-

2-cyclopropylethoxy-IO.92

lPrlMe)N-

2-cyclopropylethoxy- 0.57

IPK IMe)N-

3-Me-butoxy-

I

P

12

Et

2.2

lPr(Me)N-

Me2C=CHCH20-

0.77

P

13

Et

lPr(Me)N-

4-Et-Ph-

14

Et Et

16

Et

17

Et

18

Et

19

Me

20

Me

21

Me

iPrNH-

2-F-4-Et-Ph-

0.19

EtNH-

I-F-Ph-

4.0 2.0

O(CHICH,),N- n-butoxy-

3.8

2-pyrldyl-

3-Me-butoxy-

2.3

lPrNH

3-Me-butoxy-

1.2

lPr(Me)N-

3-Me-butoxy-

2.3

(MelzN-

2-cyclopropylethoxy

2.3

B

C

8.1 10

9.2 0.90

0.18

5.8

0.34

1.6

I 1.3

59 1.1

10 0.58

2.5

33

3.8

35

32 1.0

2.5

37 0.47

0.63 15 1.2

1.05 0.58

11 0.93

0.72 26.5 1.24

6.6

65

0.95 18

2.2

0.70 I 0.5

3.1 2.0

4.5

1.5

1.8

8.9 1.6

1.4

1.3

9.3 0.62

0.93

3.9

1.3

11

1.04 14.7

0.31 0.66

3.3

6.5 0.90

2.5 1.6

0.45

-I

7.2

0.61 65

0.25 0.14

0.59

9.8 0.77

0.80

2.5

0.79

D

3.5 2.3

0.30

0.70 0.38

0.38

0

4.4 5.3

0.30

0.16

B

1.5

2.7

0.46 O(CH2CH,),N- 3-Me-butoxy-

0.84

0.38

0.77

0.75 0.39

1.3

C

0.21

1.1

1.6

C

D

0.92

0.21 2.0

0.54

3.3 4.7

1.83

0.97

C

15

I

0.39 0.50

0.10

C

8.0 4.4

0.88 12

0.20l0.30

1-butyl-0-CH,-

0.71

2.3 0.5610.64

0.33 lPr(Me)N-

0.5C

7.8 7.6

2.1

1.2

P Et

0.17

0.60 I 0.42

0.61

1.9

2.3 1.0

0.87

c

11

0.28 0.11

1.7

C

1.2

0.22

4.3

1.4

C

0.36

1.5 0.48 0.13

2.3

C

a.7

1.5 0.21 0.14

1.3

B 5

0.29 0.23 2.5

A

7.7

3.2

2.3

12.5 0.47

2.4 1.2

12

12 0.96

a. ATI and AT2 potenciesare mean values of the results of severalindependent measurements in fresh preparations of membrane fraction, each run in triplicate. The ATz/ATl ratios were calculated as mean values of ratios obtained when side by sidedetermmations of ATI and AT2 were run each time. b. Determined

in rabbit aorta membrane

preparation.

l7 c. Determined

in rat midbrain membrane preparation. I8 d. Determined in human adrenal membrane preparation stabilized with 2 mg/ml of bovine serum albumin (BSA). For ATI and AT2 potency determination DuP 753 and I’D 121981 (1 Frn) were used to eradicate competing binding to ATIand AT2 respectively. Higher IC50 values obtained in the human adrenal receptors were due to nonspecific binding of antagonists to BSA. Several antagonists were tested in the absence of BSA using cloned AT1 human receptors expressed in CHO cells, and had IC50 values 30-60 fold lower.

T. W. GLINKAet al.

2342

Relatively small structural Ang II antagonist, normotensive

modifications

was shown

rats and dogs.

gave rise to changes in relative receptor

to be a potent,

orally

L-163$79 maintained

active

balanced

inhibitor

binding affinities.

of Ang II-induced

binding affinity following

L-163579, a fully balanced

pressor

response

Iv and po administration

in conscious in rats and

dogs. Acknowedgement : The authors wish to thank D. J. Carini;J. V. Duncia; R. R. Olson; J. R. Pruitt; M. L. Quan and R. R. Wexler of DuPont Merck Research Laboratories for their contributions and collaboration aimed at the discovery of balanced AT1 /AT2 receptor antagonists. REFERENCES

9 10

11 12 13 14

15 16 17 18

Author to whom correspondence should be sent. Present address: Microcide Pharmaceuticals 850 Maude Avenue, Mountain View, CA 94043. Wexler, R. R.; Carini, D. J.; Duncia, J. V.; Johnson, A. L.; Wells, G. J.; Chiu, A. T.; Wong, P. C.; Timmermans, P. B. M. W. M. Am. J. Hypertension 1992,5,2095-2205. Timmermans, P.B.M.W.M., Chiu, A. T., Herblin, W.F., Wong, PC., Smith, R.D., J. Hypertension, 1992, S(6): p. 406-410. Timmermans, P. B. M. W. M.; Benfield, P.; Chiu, A. T.; Herblin, W. F.; Wong, P. C.; Smith, R. D. Am. J. Hypertension 1992,5, 2215-2355. Christen, Y.; Waeber, B.; Nussberger, J.; Porchet, M ; Borland, R. M.; Lee, R. J.; Maggon, K.; Shum, L.; Timmermans, P. B M. W. M.; Brunner, H. R. Circulation 1991,83, 1333-1342 de Laszlo, S. E.; Allen, E. E.; Quagliato, C. S.; Greenlee, W. J.; Patchett, A. A.; Nachbar, R B.; Siegl, P. K. S.; Chang, R S, Kivhahn, S. D.; Schorn, T. S.; Faust, K. A.; Chen, T-B, Zingaro, G J ; Lotte, V. J. Bioorganic and Med. Chem. Lett. 1993,3, 1299-i304. de Laszlo, S. E.; Quagliato, C. S.; Greenlee, W. J.; Patchett, A. A ; Chang, R. S. L.; Lotti, V. J.; Chen, T-B.; Scheck, S. A,, Faust, K. A.; Kivlighn, S. S.; Schorn, T. S.; Zingaro, G. J.; Siegl, P K. S. J. Med. Chem. 1993,X, 3207-3210. Glinka, T. W.; de Laszlo, S. E.; Tran, J.; Chang, R. S., Chen, T-B.; Lotti, V J,; Greenlee, W. J. Biorganicand Med. Chem Lett. in mess. a. Glink’a, T. W.; de Laszlo, S. E.; Siegl, P. K. S.; Chang, R. S.; Kivlighn, S. D.; Schorn, T. S.; Faust, K. A.; Chen, T-B.; Zinaaro, G J., Lotti, V. I.; Greenlee, W. J. Biorzanic and Med. Chem. Lett 1994,4,, 81-86. See also b. Navlor, E, M , ChLkravarty, P. K.; Costello, C. A.;.Chang, R.%; Chen, T-B; Faust, K A.; Lotti, V. J.; Kivlighn, S. D.; Zmgaro, G. J.; Siegl, I’. K. S.; Wong, P. C.; Carini, D. j ; Wexler, R. R ; Patchett, A. A, Greenlee, W. J. Biorganic Med Chem. Lett. 1994,4,, 6974. The choice of tissue reflects the importance of making 1C50 comparisons in a single tissue that expresses both receptor subtypes. Results communicated to us prior to publication through our collaboration with the DuPont Pharmaceutical Corporation. Recently presented: Santella, J. B; Ensinger, C. L., VanAtten, M. K.; Carini, D. J.; Wexler, R. R.; Chlu, A. T.; McCall, D. E.; Wong, P. C.; Timmermans, P. M. W. M.; Duncia, J. V 207th American Chemical Society National Meeting, San Diego, CA. March 13-17th 1994. MEDI 199. Quan, M. L; Olson, R. E.; Carini, D. J.; Ellis, C. D.; Hillyer, G. L.; Lalka, G. K.; LIU, J., VanAtten, M. K.; Chm, A. T.; Wong, P. C.; Wexler, R. R.; Timmermans, P. B. M. W. M. Biorganic Med Chem. Lett. m press.Santella III, J. B; Duncia, J. V , Ensinger, C. L.; VanAtten, M. K.; Carini, D. J.; Wexler, R. R ; Chlu, A T., Wong, P. C.; Timmermans, P. B. M. W. M. Biorganic Med Chem. Lett. in press. Suzuki, A.; Miyaura, N.; Ishiyama, T.; Sasaki, H.; Ishtkawa, M.; Satoh, M. J. Am. Chem. Sot. 1989,112, 3 14 IC50 AT2/ATl=lO, 4.9 and 11 for des-fluoro analogs of 1,3 and 4 respectively (ref Ba) Although not a homologous series, this result has been observed in other heterocyclic series investigated at Merck: unpublished results. Mukoyama, M; Nakajima, M.; Horiuchi, M; Sasamura, H; Pratt, R. E.; Dzau, V. J. J. 8101. Chem. 1993,268, 24539-24542 and Kambayashi, Y; Bardhan, S.; Takahashi, K; Tsuzuki, S.; Inui, H.; Hamakubo, T.; Inagami, T J. Biol. Chem. 1993,268, 24543-24546. Chang, R. S. L.; Siegl, P. K. S.; Clineshmidt, B. V.; Mantlo, N. B.; Chakravarty, P. K.; Greenlee, W. J.; Patchett, A. A.; Lotti, V. J. J. of Pharm. Exp. Ther. 1992,262,133-138. Radioreceptor binding assay utilizing rat midbrain tissues in the absence of BSA and presence of 5.0 mM dithiothreitol to block residual AT1 receptors as in reference 19 Siegl, P. K. S., Chang, R. S. L.; Mantlo, N. B., Chakravarty, P. K.; Ondcyka, D. L.; Greenlee, W. J,; Sweet, C. S.; Lotti, V J, J. Pharm. Exp. Ther. 1992,262,139-144. For the protocol see reference 21 in reference 6 of this manuscript.

(Received in USA 12 July 1994; accepted 31 August 1994)