Tetrahydro-isoquinoline-based factor Xa inhibitors

Article abstract of DOI:10.1021/jm9800402

Derivatives of (2-amidino-1,2,3,4-tetrahydro-isoquinolin-7- yloxy)phenylacetic acid (TIPAC) were developed as inhibitors of factor Xa (fXa). The compounds are prepared using 15 synthetic steps on average. The most potent compounds (14, 17, 22-26) display inhibition constants of K(i) = 21-55 nM but do not inhibit thrombin (K(i) = 5-> 100 μM) and only weakly inhibit trypsin (K(i) = 0.08-5 μM). They bear a second basic moiety, e.g., substituted 1-(iminomethyl)piperidines, which is linked to C-4 of the phenyl group of TIPAC via an oxygen atom. The inhibition constants of these compounds are almost independent of the size of the (iminomethyl)piperidine substituent. Due to the fact that fXa displays two cation binding sites, namely, the S1 and S4 sites, in principle two binding modes are conceivable for the novel dibasic fXa inhibitors. Molecular modeling experiments based on the X-ray structures of uninhibited fXa and the DX-9065a/fXa complex were carried out. The results taken together with the inhibition constants clearly favor one binding mode: the tetrahydro-isoquinoline fills the S1 pocket even better than the naphthalene moiety of DX-9065a, and the (iminomethyl)piperidine residues occupy the S4 site.

Full text of DOI:10.1021/jm9800402

J . Med. Chem. 1998, 41, 4983-4994
4983
Tetr a h yd r o-isoqu in olin e-Ba sed F a ctor Xa In h ibitor s
Ralf Kucznierz,*,‡ Frank Grams,‡ Herbert Leinert,‡ Klaus Marzenell,‡ Richard A. Engh,§ and
Wolfgang von der Saal‡
Chemical Research Department, Boehringer Mannheim GmbH, D-68298 Mannheim, Germany, and Max-Planck-Institut
fu¨r Biochemie, D-82152 Martinsried, Germany
Received J anuary 21, 1998
Derivatives of (2-amidino-1,2,3,4-tetrahydro-isoquinolin-7-yloxy)phenylacetic acid (TIPAC) were
developed as inhibitors of factor Xa (fXa). The compounds are prepared using 15 synthetic
steps on average. The most potent compounds (14, 17, 22-26) display inhibition constants of
Ki ) 21-55 nM but do not inhibit thrombin (Ki ) 5->100 µM) and only weakly inhibit trypsin
(Ki ) 0.08-5 µM). They bear a second basic moiety, e.g., substituted 1-(iminomethyl)piperidines,
which is linked to C-4 of the phenyl group of TIPAC via an oxygen atom. The inhibition
constants of these compounds are almost independent of the size of the (iminomethyl)piperidine
substituent. Due to the fact that fXa displays two cation binding sites, namely, the S1 and S4
sites, in principle two binding modes are conceivable for the novel dibasic fXa inhibitors.
Molecular modeling experiments based on the X-ray structures of uninhibited fXa and the
DX-9065a/fXa complex were carried out. The results taken together with the inhibition
constants clearly favor one binding mode: the tetrahydro-isoquinoline fills the S1 pocket even
better than the naphthalene moiety of DX-9065a, and the (iminomethyl)piperidine residues
occupy the S4 site.
In tr od u ction
anti-fXa activity with a satisfactory selectivity profile
(Ki ) 0.041 µM, Ki > 2000 µM, Ki ) 0.62 µM,
fXa
thrombin
trypsin
Factor Xa (fXa), a trypsin-like serine protease, plays
a pivotal role in the coagulation process. It is produced
from its zymogen factor X1 by cleavage of the Arg194-
Ile195 peptide bond upon activation of either the
intrinsic or extrinsic pathway of the coagulation cas-
cade.2 Released fXa participates in the prothrombinase
complex, which includes cofactor Va and calcium ions
assembled on a phospholipid membrane. This complex
generates thrombin from prothrombin, which ultimately
activates platelets and causes fibrin deposition.
Ki
) 23 µM).11c However, the favorable profile of
plasmin
The two branches of the coagulation cascade converge
on fXa which has therefore become a major target in
the field of anticoagulant drug research.3 A variety of
fXa inhibitors have been isolated from natural sources:
e.g., tick anticoagulant peptide from extracts of Orni-
thodorus mubata,4 antistasin from the salivary glands
of the Mexican leech Haementeria officinalis,5 the
anclystoma caninum anticoagulant peptide from soluble
protein extracts of canine hookworms,6 and ecotin from
the periplasm of Escherichia coli.7
Considerable efforts are being focused on synthetic,
low-molecular-weight fXa inhibitors. Benzamidine mod-
erately inhibits diverse serine proteases including fXa
this compound has to be paid for with a toilsome
synthesis. DX-9065a has been prepared in a sequence
comprising more than 20 reaction steps,11b of which the
main effort is attributed to the poor accessibility of the
2,7-di-C,C-substituted naphthamidine precursor.12
Hence, our idea was to design novel P1 building blocks
suitable for fXa inhibition. Initially, modeling studies
based on the X-ray structure of fXa13 and on the
structure of fXa complexed with DX-9065a14 were car-
ried out in order to scan the enzymes’ S1 site. This
approach resulted in the assumption that a bioisosteric
substitution, of the 2,7-di-C,C-substituted naphthami-
by occupation of the enzymes’ S1 subsites (Ki ) 410
fXa
µM, Ki
) 220 µM, Ki
) 35 µM, Ki
) 350
thrombin
trypsin
plasmin
µM).8 The lack of selectivity is due to the similarity of
the S1 sites of the enzymes. The selectivity is improved
by the introduction of a second basic moiety. Various
arylbisamidine derivatives such as DABE9a or BABCH9b
have therefore been prepared in order to improve anti-
fXa activity as well as selectivity.10 Daiichi’s naphtha-
midine-derived dibasic DX-9065a11 combines reasonable
‡ Boehringer Mannheim GmbH.
§ Max-Planck-Institut fu¨r Biochemie.
10.1021/jm9800402 CCC: $15.00 © 1998 American Chemical Society
Published on Web 11/12/1998

4984 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25
Kucznierz et al.
piperidine derivative 20 as well. The enamine 35
results from condensation of released 30 with excess
dimedone.20 Modification of the deprotection conditions
by replacing dimedone with tributyltin hydride21 finally
afforded 30 in good yields. 20 and 30 were reacted with
various ethyl imidates to give 22-24 and 32. The
carboxylic acid derivatives 17-19, 21, 25, 26, 29, 31,
33, and 36 were obtained upon conventional alkaline
hydrolysis of the corresponding ethyl esters 14-16, 20,
22, 23, 28, 30, 32, and 35.
Resu lts a n d Discu ssion
F igu r e 1. Bioisosteric transformation of the amidino-naph-
The inhibition constants of 13-36 toward fXa and the
structurally related serine proteases thrombin, trypsin,
and plasmin are summarized in Table 1. The dibasic
compounds 14, 17, and 22-26 are the most potent
derivatives with Ki values toward fXa in the lower
nanomolar range. A closer inspection of the inhibition
constants led to a better understanding of the binding
mode of the new inhibitors. It has been suggested
earlier that the S122 and S4 pockets of fXa are very
similar.14 Both consist of hydrophobic walls and a
negatively charged bottom. Hence, two binding modes
are possible for the dibasic inhibitors. In the first one,
the amidino-tetrahydro-isoquinoline is the P1 residue
and the second basic group, e.g., the amidino-piperidine
of 14 or 17, occupies the S4 site. This binding mode
resembles that of DX-9065a in fXa.14 In the second
binding mode, the positions of the basic groups are
inverted; i.e., the amidino-piperidine is the P1 residue.
This mode is also conceivable, since amidino-piperidines
are P1 residues of potent inhibitors of thrombin,23 which
has an almost identical S1 pocket. To solve this
dichotomy, we took advantage of the small structural
differences of the S1 and S4 pockets of fXa: The S1
pocket is accessible only from the top, while one wall of
the S4 site is open to the solvent, and thus it can
potentially accommodate bulkier groups which will not
be able to enter the S1 site. Hence, we prepared the
compounds 22-26 which bear bulkier substituents at
the piperidine moiety. The inhibition constants turned
out to be independent of the size of the substituents and
very similar to those of the amidino-piperidines (Table
1). Therefore, the piperidines are most likely the P4
residues (first binding mode).
To further corroborate this interpretation, we under-
took a simple molecular dynamics simulation of the S1
pocket residues and inhibitor docking experiments.24
This was thought to be important to exclude the
possibility of bulky groups entering the S1 site of fXa,
since it had been observed previously that the S1 site
is flexible: its rim moved by almost 2 Å toward the
naphthalene moiety upon binding of DX-9065a.14 More-
over, the temperature factors of the corresponding
atoms in the fXa/DX-9065a structure are remarkably
high compared to those of several thrombin/inhibitor
structures. The molecular dynamics simulation of the
S1 pocket residues revealed a high degree of flexibility
also on the bottom of the S1 site which is most
pronounced in the orientations of the side chain of
Asp189 and the carbonyl group of Ala190. These
residues are involved in the binding of the amidino
group of DX-9065a in the fXa/DX-9065a14 and of the
guanidino group of the C-terminal Arg138 side chain
thylmethyl residue.
dine moiety with the 2-carbamimidoyl-1,2,3,4-tetrahy-
dro-isoquinolin-7-yloxy template (Figure 1) would pro-
vide a novel P1 residue suitable for fXa inhibition.
Herein we report on the synthesis and activity of
(1,2,3,4-tetrahydro-isoquinolin-7-yloxy)phenylacetic acid
derivatives (“TIPAC derivatives”), a novel class of low-
molecular-weight inhibitors of factor Xa.
Ch em istr y
The synthesis of the central building block 6, which
provides the common scaffold for the tetrahydro-iso-
quinoline-based compounds, is depicted in Scheme 1.
3-(Benzyloxy)benzaldehyde is reacted with amino-
acetaldehyde diethyl acetal to give the corresponding
Schiff base 1. Pomeranz-Fritsch type cyclization medi-
ated by boron trifluoride and trifluoroacetic anhydride15
and simultaneous cleavage of the O-benzyl group afford
2, which is subsequently hydrogenated to give 1,2,3,4-
tetrahydro-isoquinolin-7-ol (3). This four-step synthesis
is performed in a convenient one-pot procedure without
purification of the intermediates in an overall yield of
more than 60%. Boc protection of the crude product
followed by alkylation of the phenolic hydroxy group
with the chloromandelate derivative 9 and subsequent
O-debenzylation provide the key intermediate 6 in good
yields.
Scheme 2 pictures the preparation of 9 via its cyano-
hydrin precursor 7, which is obtained from 4-(benzyl-
oxy)benzaldehyde and potassium cyanide in the pres-
ence of ammonium chloride. Pinner reaction followed
by acid-catalyzed alcoholysis releases the mandelic acid
derivative 8, which is subsequently chlorinated by
phosphorus pentachloride.
As outlined in Schemes 3 and 4, the key intermediate
6 is condensed with 10a -f under Mitsunobu condi-
tions16 to give 11a -f. Acid-catalyzed removal of the Boc
groups yields the tetrahydro-isoquinolines 12a -f, which
afford the corresponding guanidines 13-16, 27, and 28
after treatment with 1H-pyrazole-1-carboxamidine hy-
drochloride.17 Palladium-catalyzed cleavage of the allyl
carbamate 13 in the presence of dimedone18 releases the
piperidine derivative 20.
Attempts to deprotect the pyrrolidine moiety of 27 in
the same manner did not afford the desired amine 30
but yielded a mixture of the enamine 35 and the allyl-
substituted pyrrolidine 34 (Scheme 5). The latter is
being formed due to retro allyl migration after carbon
dioxide elimination. Hence, the intermediate pyrroli-
dine 30 is a more effective allyl scavenger than dime-
done19 and a more effective one than the corresponding

Tetrahydro-isoquinoline-Based fXa Inhibitors
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25 4985
Sch em e 1a
a
Reagents and conditions: (i) H2N-CH2-CH-(OCH3)2, toluene, reflux; (ii) (CF3CO)2O, BF3-OEt2, toluene, rt; (iii) PtO2, H2, glacial acetic
acid, rt; (iv) Boc2O, NEt3, CH2Cl2, 5 °C; (v) K2CO3, CH3CN, reflux; (vi) Pd/C, H2, ethyl acetate, rt.
Sch em e 2a
overall binding energy. Substitution of the second
nitrogen atom by a hydrophobic methyl group (22, 25)
illuminates specificity features between the different
enzymes. While this modification is unfavorable for
thrombin and trypsin inhibition, there is almost no
effect on the activity versus fXa. However, the equiva-
lent transformation in the corresponding pyrrolidine
series (28, 29) results in a slight increase of potency on
a generally lower level (32, 33). An enlargement of the
methyl group does not effect considerable changes in
potency toward fXa (compare 22/23/24 and 25/26). A
conspicuous difference is observed only toward trypsin,
where a 10-fold increase in potency occurs when the
methyl group of compound 25 is replaced with the
p-methoxyphenyl substituent (26). Obviously this hy-
drophobic substitution does not cause an essential
contribution to the overall binding energy on fXa. Two
slightly different binding modes of the piperidine moi-
eties in the S4 site can be considered, depending on the
nature of the terminal residue. Compounds substituted
with a small terminal group on the piperidine nitrogen
atom, such as the amidino-piperidine derivative 17,
arrange in a DX-9065a-like manner, whereas the bulky
substituted piperidine nitrogen atom of 26 shifts slightly
to the line formed by Glu97 and Phe174 due to the
linear alignment of the methoxyphenyl substituent
between Glu97, Thr98, and Phe174. Replacing the basic
hydrogen donor substituent on the P4 residue with a
neutral hydrogen acceptor fragment, for instance, imi-
noethyl (22) versus acetyl (15), results in a dramatic
loss of potency toward fXa by a factor of 100. This effect
is caused by the lack of the ionic interaction in the S4
site and demonstrates the importance of the correct
pharmacophore in this position. Finally the elimination
of substituent on the P4 heterocycle (Table 1, X ) NH)
also results in less potent compounds. Although the P4
residue of 20, for instance, still provides the piperidine
NH as hydrogen donor functionality, the observed
activity is poor. Moreover, the replacement of the
hydrogen donor group >NH- with the hydrogen accep-
tor group -O- does not considerably influence the
affinity. Apparently in this position a hydrogen bond
does not play an important role. This is in agreement
with modeling data and the structure of DX-9065a in
fXa.14 The appropriate position is too far away from any
hydrogen donor or hydrogen acceptor site.
a
Reagents and conditions: (i) NaCN, NH4Cl, H2O, 5 °C; (ii) HCl,
EtOH, 5 °C; (iii) PCl5, CH2Cl2, rt.
of the EGF2 domain of a neighboring symmetry equiva-
lent fXa molecule in the inhibitor-free X-ray structure
of fXa.13 In the docking experiments it became evident
that the amidino-tetrahydro-isoquinoline residue fills
the S1 site even slightly better than the naphthamidine
of DX-9065a. The bulky substituted piperidine moiety
of 23 and 26 cannot enter this site, despite its flexibility,
but it fits into the S4 pocket with the methoxyphenyl
group exposed to the bulk solvent. In the S1 site, the
tetrahydro-isoquinoline moiety can arrange in such a
way that one C-1 hydrogen atom occupies the same
position as the C-1 hydrogen atom of the naphthalene
ring of DX-9065a, while the second C-1 hydrogen atom
occupies a spatial gap which appears in the fXa/DX-
9065a structure at the interface between enzyme and
inhibitor (Figure 2).
As in the fXa/DX-9065a complex the second main
interaction site is presented by the fXa-specific aryl-
binding site (S4). The pyrrolidine ring of DX-9065a is
completely buried by the aromatic moieties of Phe174
and Tyr99. The aromatic residues align almost parallel
to the ring (stacking interaction), while the aliphatic
part of the Glu97 side chain and Trp215 arrange in a
perpendicular orientation. In our series the iminoalkyl-
and amidino-substituted piperidine moieties of 14, 17,
and 22-26 bind in a more effective way (Ki ) 0.021-
0.055 µM) compared with the corresponding pyrrolidine
residues of 28, 29, 32, and 33 (Ki ) 0.08-0.2 µM) due
to a more favorable alignment of the positively charged
group in the aryl-binding site (S4). A similar trend is
observed when comparing the pyrrolidine-based DX-
9065a with its piperidine analogue.25 As confirmed by
modeling, one of the amidino nitrogen atoms of the
amidino-piperidine moiety of compound 14sand the
appropriate one of 17sforms a hydrogen bond to Glu97.
This ionic interaction contributes considerably to the
The nature of the carboxylate moieties of the TIPAC
derivatives does not influence their inhibitory activity
toward fXa. In any case the Ki value of a particular

4986 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25
Kucznierz et al.
Sch em e 3a
a
Reagents and conditions: (i) DEAD, PPh3, THF, rt; (ii) HCl, Et2O, 5 °C; (iii) 1H-pyrazole-1-carboxamidine hydrochloride, DIPEA,
DMF, 5 °C; (iv) EtOH, NaOH aq, 5 °C; (v) Pd(PPh3)4, dimedone, THF, rt; (vi) R(dNH)OEt, NEt3, EtOH, rt.
acid derivative is similar to that of the corresponding
ethyl ester (e.g., the couples 14/17, 22/25, and 23/26).
This demonstrates that the carboxylate moieties are
involved neither in direct ionic interaction nor in donor-
acceptor interactions with fXa. They are exposed to the
solvent as suggested by modeling studies and in analogy
to the binding of DX-9065a in fXa. However, regarding
the selectivity a distinct difference between acid and
ester derivatives emerges. The ester derivatives, for
instance, 14, 22, and 23, show moderate inhibitory
activity toward thrombin (Ki ) 8-15 µM), trypsin (Ki
) 0.2-0.4 µM), and plasmin (Ki ≈ 25 µM) similar to
the observed selectivity profile of the ethyl ester of DX-
9065a.26 The corresponding acids (17, 25, 26) also
moderately inhibit trypsin and plasmin, but in analogy
to DX-9065a, they do not inhibit thrombin. The struc-
tural reasons for the observed selectivity profiles become
clear upon contemplation of the X-ray structure of BM
12.1700, a precursor of DX-9065a in thrombin (PDB
code: luvu).27 In this structure the binding of the
naphthamidine moiety (P1) is accompanied by a main
chain transformation which results in a constriction of
the S1 site. The energy required to alter the thrombin
structure is (over)compensated by the interaction of the
ester group of the inhibitor with the hydrophobic S2 site.
An analogous binding mode is assumed for the ester
derivatives of this work: interaction of the amidino-
tetrahydro-isoquinoline group with a constricted S1 site
along with the extension of the ester groups into the
hydrophobic S2 site results in moderate thrombin
inhibition. Removal of the ester groups eliminates the
essential S2 site interaction and thus withdraws the
basis for a reasonable occupation of the S1 site. In other
words: thrombin is not inhibited by the acid derivatives.
In trypsin the situation is different. The S1 site is less
pronounced as in thrombin and does not require a
movement of its rim toward the amidino-tetrahydro-
isoquinoline residue, as previously shown in the X-ray
structures of naphthamidine-bound trypsin.25 A par-
ticular S2 pocket is not present in trypsin, and further
interactions are only of minor importance. This results
in a moderate inhibition of both ester- and acid-derived
compounds of this series. Plasmin inhibition is assumed
to follow similar principles, although the inhibition
constants are significantly lower (by about 2 orders of
magnitude compared to those found for trypsin).

Tetrahydro-isoquinoline-Based fXa Inhibitors
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25 4987
Sch em e 4a
a
Reagents and conditions: (i) DEAD, PPh3, THF, rt; (ii) HCl, Et2O, 5 °C; (iii) 1H-pyrazole-1-carboxamidine hydrochloride, DIPEA,
DMF, 5 °C; (iv) EtOH, NaOH aq, 5 °C; (v) Pd(PPh3)4, Bu3SnH, CH2Cl2, 5 °C; (vi) R(dNH)OEt, NEt3, EtOH, rt.
Sch em e 5a
assay. The ED200 values of the aPPT and TT assays
are listed in Table 1.
Con clu sion
We have introduced the amidino-tetrahydro-isoquino-
lin-7-yloxy template as a novel P1 residue for the
inhibition of the blood coagulation factor Xa. On the
basis of this moiety, we-have developed (2-amidino-
1,2,3,4-tetrahydro-isoquinolin-7-yloxy)phenylacetic acid
derivatives (TIPAC derivatives) as a novel class of low-
molecular-weight fXa inhibitors. They were prepared
in 15 reaction steps on average. Substituted iminoalkyl-
or amidino-piperidine moieties proved to be the most
effective P4 residues in this series. The best compounds
(17, 25, and 26) inhibit fXa with Ki values in the lower
nanomolar range and display a reasonable selectivity
profile.
Exp er im en ta l Section
Gen er a l. Starting materials and reagents were purchased
from commercial sources (Aldrich or Lancaster) and used
without further purification, unless otherwise noted. Dry
solvents: acetone and dichloromethane distilled from P2O5
distilled using a mirrored Vigreux column; DMF distilled from
calcium hydride; methanol distilled from sodium methanolate
(10 g of sodium/L of methanol); tetrahydrofuran distilled from
LiAlH4; toluene distilled from sodium hydride; distilled sol-
vents stored over molecular sieves (3 Å; Merck Darmstadt);
diethyl ether kept over Al2O3 (alumina N, activity grade I; ICN
Biomedicals). Air- and moisture-sensitive reactions were
carried out under inert gas atmosphere (argon or nitrogen)
using oven-dried (110 °C) glassware. 1H NMR: DMSO-d6
(unless otherwise stated), Bruker AC 250 spectrometer, TMS
as internal standard, chemical shifts in δ ppm. 13C NMR:
DMSO-d6 (unless otherwise stated), Bruker AC 250 spectrom-
eter at 63 MHz, TMS as internal standard, chemical shifts in
δ ppm. Mass spectra: Finnigan MAT 312, Micro PDP-11
computer, Finnigan program SS300. Melting points: Bu¨chi
a
Reagents and conditions: (i) Pd(PPh3)4, dimedone, THF, rt;
(ii) EtOH, NaOH aq, 5 °C.
The anticoagulant activity and the selectivity profile
of the compounds 14, 17, and 22-26 are also demon-
strated by the results of the plasma coagulation assays.
The influence of the inhibitors on the activated partial
thromboplastin time (aPTT) mirrors both the fXa and
thrombin inhibition, while the thrombin time (TT) is
sensitive to thrombin inhibition, but not for fXa inhibi-
tion. The inhibitors prolongate the aPTT considerably.
This is expressed by the values of the aPTT doubling
time concentration (ED200(aPTT): 3-11 µM). The
selectivity profile is confirmed by the results of the TT

4988 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25
Kucznierz et al.
Ta ble 1. Inhibition Constants and Anticoagulant Activity of Compounds 13-36
a
Kia
ED200
compd
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
formula
X
R1
fXa
thrombin
trypsin
plasmin
aPTT
TT
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
B
N-Aloc
Et
Et
Et
Et
H
3
4
8
ndb
0.2
10
3
0.2
5
12
3
6
0.4
0.2
0.08
2
0.2
9
2
1
6
10
2
10
10
10
10
2e
14
25
10
26
260
3
100
250
9
150
>500
26
190
3
6
10
11
7
200
10
40
26
50
>500
54
200
N-C(dNH)NH2
N-acetyl
0.028
3
>100
O
2
8
500
N-C(dNH)NH2
N-acetyl
0.044
0.4
>100
>100
>100
16
44
>500
>500
>500
71
H
H
ndb
25
O
N-H
N-H
3
2
2
Et
H
Et
Et
Et
H
25
25
>100
>500
N-C(dNH)Me
N-C(dNH)Arc
N-C(dNH)Et
N-C(dNH)Me
N-C(dNH)Arc
N-Aloc
N-C(dNH)NH2
N-C(dNH)NH2
N-H
0.030
0.021
0.030
0.055
0.026
0.2
0.2
0.2
0.4
15
5
20
25
53
32
70
ndb
ndb
52
>100
>100
>100
13
>100
>100
>100
>100
>100
>100
>100
>100
>100e
>500
>500
500
300
>500
140
>500
100
>500
240
90
>500
H
ndb
10
Et
Et
H
Et
H
Et
H
Et
Et
H
45
ndb
40
N-H
1
10
N-C(dNH)Me
N-C(dNH)Me
N-allyl
0.1
0.080
1
ndb
ndb
50
10
30
27
24
N-dmoched
N-dmoched
0.2
50
36
0.2
50
200
DX-9065a
0.040e
11e
a
b
d
In µM. nd, not determined. c Ar ) 4-MeO-C6H4-. dmoche ) 5,5-dimethyl-3-oxocyclohex-l-enyl. e As determined according to the
procedures described in the Experimental Section (for original data, see ref 11c).
F igu r e 2. Proposed binding of the isoquinoline moiety of TIPAC derivative 25 to the S1 site of factor Xa (left) in comparison
with the binding of the naphthamidine moiety of DX-9065a (right) as determined in the X-ray structure.14
model 530 apparatus, uncorrected. TLC: TLC plates 0.25-
mm silica gel 60 F254 (Merck Darmstadt); detection achieved
under UV light (254 nm) or by spraying with ninhydrin or
phosphomolybdic acid or Awe’s reagent (sodium azide/iodine).
Column chromatography: Merck silica gel 60 (70-230 mesh).
Analytical HPLC: reverse-phase LiChrospher 60 RP-Select-B
column, 5 µm, size 4 × 125 mm (Merck Darmstadt); eluents
acetonitrile/water (10/90-30/70) or methanol/water (10/90-

Tetrahydro-isoquinoline-Based fXa Inhibitors
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25 4989
30/70). Preparative HPLC: reverse-phase LiChroprep RP-18
column, 15-25 µm, size 4 × 25 cm (Merck Darmstadt).
Microanalytical results indicated by the symbols of the ele-
ments were within (0.4% of the theoretical values; if only
mass spectral data are given, the purity of these compounds
has been assessed to be >98% by TLC or HPLC. Compounds
were named following IUPAC rules as applied by AUTONOM,
Beilstein Informationssysteme GmbH, Frankfurt/Main, Ger-
many. Modeling studies have been carried out with the
Insight II/Discover program package (MSI, San Diego, CA).
DX-9065a was sythesized according to published procedures.11b,12
Isoqu in olin -7-ol (2). Aminoacetaldehyde dimethyl acetal
(79 g, 0.750 mol) was added to 3-(benzyloxy)benzaldehyde
(0.500 mol, 106 g) in 1100 mL of toluene and the mixture
refluxed for 6 h using a Dean-Stark trap. After cooling to 5
°C trifluoracetic acid anhydride (212 mL, 1.500 mol) and boron
trifluoride etherate (185 mL, 1.500 mol) were added under
Filtration followed by concentration in vacuo afforded 7.8 g
(91%) of the title compound as a white solid: mp 152-155 °C.
(+)-FAB-MS: 428 (MH+). 1H NMR: δ ) 1.11 (t, 3H), 1.42 (s,
9H), 2.68 (t, 2H), 3.50 (t, 2H), 4.11 (m, 2H), 4.43 (s, 2H), 5.75
(s, 1H), 6.76 (m, 4H), 7.02 (d, 1H), 7.31 (d, 2H), 9.60 (s, 1H).
13C NMR: δ ) 14.0, 27.4, 28.1, 41.4, 44.8, 60.9, 77.1, 78.9,
112.6, 113.7, 115.4, 125.8, 127.2, 128.9, 129.6, 134.7, 153.9,
155.4, 158.0, 169.8. Anal. Calcd (C24H29NO6) C, H, N.
(4-(Ben zyloxy)p h en yl)h yd r oxya ceton itr ile (7). 4-(Ben-
zyloxy)benzaldehyde (42.6 g, 0.200 mol) was dissolved in 500
mL of ether, and 32.0 g (0.600 mol) of ammonium chloride in
90 mL of water and 29.4 g (0.600 mol) of sodium cyanide in
80 mL of water were added in succession at 5 °C. The reaction
mixture was allowed to stir for 24 h at 5 °C. Organic and
aqueous layers were separated, the latter was extracted with
ethyl acetate, the combined organic extracts were washed with
water and brine and dried, and the solvent was removed in
vacuo. The remaining white solid [47.6 g, 99%; EI-MS 240
(M+)] was used in the next step without further purification.
(4-(Ben zyloxy)p h en yl)h yd r oxya cetic Acid Eth yl Ester
(8). 7 (47.6 g, 0.198 mol) was dissolved in 200 mL of diethyl
ether; 12.8 mL (0.260 mol) of ethanol and 8.0 g (0.220 mol) of
dry hydrogen chloride were added at 5 °C. The reaction
mixture was allowed to stand for 24 h at 5 °C. The precipi-
tated material was collected by filtration and suspended in a
mixture of 300 mL of ethanol and 600 mL of water. After
stirring for 72 h at ambient temperature the precipitated white
solid was collected, washed with water, and dried: yield 50.0
g (88%); mp 89-92 °C. (+)-FAB-MS: 287 (MH+). 1H NMR:
δ ) 1.15 (t, 3H), 4.07 (m, 2H), 5.00 (d, 1H), 5.05 (s, 2H), 5.88
(d, 1H), 6.95 (d, 2H), 7.27-7.47 (m, 7H). Anal. Calcd
(C17H18O4) C, H.
(4-(Ben zyloxy)p h en yl)ch lor oa cetic Acid Eth yl Ester
(9). PCl5 (10.4 g, 0.050 mol) was added to a solution of 8 (14.3
g, 0.050 mol) in 250 mL of dichloromethane at 5 °C and the
reaction mixture stirred for 24 h at room temperature.
Concentration in vacuo followed by column chromatography
(isohexane/ethyl acetate, 9:1) yielded 13.0 g (85%) of the title
compound as a yellow, crystalline solid: mp 45-47 °C. EI-
MS: 304 (M+). 1H NMR: δ ) 1.18 (t, 3H), 4.16 (m, 2H), 5.11
(s, 2H), 5.81 (d, 1H), 7.04 (d, 2H), 7.30-7.46 (m, 7H). 13C
NMR: δ ) 13.8, 58.4, 62.0, 69.4, 115.0, 127.7, 127.9, 128.3,
128.5, 129.5, 136.8, 159.0, 168.1. Anal. Calcd (C17H17ClO3)
C, H, Cl.
4-Hyd r oxyp ip er id in e-1-ca r boxylic Acid Allyl Ester
(10a ). A solution of 11.7 mL of allyl chloroformate (0.11 mol)
in 20 mL dichloromethane was added dropwise to a mixture
of 10.1 g (0.10 mol) of 4-hydroxypiperidine and 18.0 mL (0.12
mol) of DBU in 200 mL of dichloromethane at 5 °C. The
organic layer was extracted with aqueous acetic acid and
saturated sodium hydrogen carbonate solution and dried (Na2-
SO4). Removal of the solvent in vacuo gave pure 10a as a
colorless oil: yield 18.4 g (99%). EI-MS: 185 (M+). 1H NMR:
δ ) 1.18-1.36 (m, 2H), 1.60-1.78 (m, 2H), 3.05, (m, 2H), 3.57-
3.78 (m, 3H), 4.48 (d, 2H), 4.72 (d, 1H), 5.25 (dd, 2H), 5.91 (m,
1H). 13C NMR: δ ) 33.9, 41.1, 65.1, 65.3, 116.7, 133.6, 154.2.
4-Hyd r oxyp ip er id in e-l-ca r boxylic Acid ter t-Bu tyl Es-
t er (10b ). To a solution of 20.2 g (0.20 mol) of 4-hydroxy-
piperidine and 56.0 mL (0.40 mol) of triethylamine in 200 mL
of dichloromethane was added 50.0 g (0.22 mol) of di-tert-butyl
dicarbonate in portions at 5 °C. After stirring at room
temperature for 16 h the mixture was worked up following
the procedure used for 10a : yield 37.8 g (94%); white crystals;
mp 68 °C. EI-MS: 201 (M+). 1H NMR: δ ) 1.13-1.31 (m,
2H), 1.39 (s, 9H), 1.61-1.72 (m, 2H), 2.94, (t, 2H), 3.61-3.70
(m, 3H), 4.66 (s, 1H). 13C NMR: δ ) 28.0, 34.0, 43.8, 65.6,
78.3, 153.8. Anal. Calcd (C10H19NO3) C, H, N.
nitrogen in succession at such
a rate that the internal
temperature was kept below 10 °C. After stirring for 5 days
at room temperature the precipitated material was separated
by filtration, washed with diethyl ether several times, and
dissolved in 750 mL of water. The pH value was adjusted to
pH 9 by adding concentrated aqueous ammonia and the
precipitated product separated by filtration, followed by wash-
ing with diethyl ether and drying in vacuo: yield 53.2 g (73%);
light yellow solid; mp 228-230 °C. EI-MS: 145 (M+). 1H
NMR: δ ) 7.35 (s, 1H), 7.37 (m, 1H), 7.72 (d, 1H), 7.83 (d,
1H), 8.30 (d, 1H), 9.12 (s, 1H), 10.25 (s, 1H). 13C NMR: δ )
107.8, 120.0, 123.2, 128.1, 129.7, 129.9, 139.9, 150.4, 156.3.
Anal. Calcd (C9H7NO) C, H, N.
1,2,3,4-Tetr a h yd r o-isoqu in olin -7-ol Hyd r oa ceta te (3).
2 (53.2 g, 0.365 mol) was dissolved in 1000 mL of glacial acetic
acid and hydrogenated for 48 h at room temperature using
prehydrogenated platinum dioxide (3.5 g) as catalyst. Filtra-
tion followed by concentration and addition of 50 mL of acetone
gave a clear solution. Addition of diethyl ether resulted in
precipitation of pure 1,2,3,4-tetrahydro-isoquinolin-7-ol hy-
droacetate: yield 44.9 g (83%); white solid; mp 179-182 °C.
EI-MS: 149 (M+). 13C NMR: δ ) 20.8, 26.2, 42.4, 46.0, 112.3,
113.8, 123.6, 129.5, 134.1, 155.3, 171.9. Anal. Calcd (C11H15
NO3) C, H, N.
-
7-H yd r oxy-3,4-d ih yd r o-1H -isoq u in olin e-2-ca r b oxylic
Acid ter t-Bu tyl Ester (4). A mixture of 17.1 g (0.079 mol)
of di-tert-butyl dicarbonate in 170 mL of dichloromethane was
added dropwise to a stirred suspension of 16.4 g (0.079 mol)
of 3 and 32.6 mL (0.235 mol) of triethylamine in 164 mL of
dichloromethane at 5 °C. Stirring was continued at 5 °C for
1 h, followed by evaporation of the volatiles. The residue was
redissolved in ethyl acetate and this solution washed in
succession with aqueous acetic acid, saturated sodium hydro-
gen carbonate solution, and brine and dried (Na2SO4). Re-
moval of the solvent in vacuo gave pure 4 as a white solid:
yield 17.5 g (89%); mp 140-142.5 °C; EI-MS: 249 (M+). 1H
NMR: δ ) 1.44 (s, 9H), 2.64 (t, 2H), 3.50 (t, 2H), 4.37 (s, 2H),
6.55 (m, 2H), 6.92 (d, 1H), 9.17 (s, 1H). 13C NMR: δ ) 27.3,
28.0, 41.5, 45.1, 78.1, 112.2, 113.7, 124.3, 129.3, 134.2, 153.9,
155.5. Anal. Calcd (C14H19NO3) C, H, N.
7-[(4-(Ben zyloxy)p h en yl)(et h oxyca r b on yl)m et h oxy]-
3,4-d ih yd r o-1H-isoqu in olin e-2-ca r boxylic Acid ter t-Bu tyl
Ester (5). A mixture of 7.5 g (0.030 mol) of 4, 11.4 g (0.037
mol) of 9, and 8.4 g (0.060 mol) of K2CO3 in 150 mL of
acetonitrile was refluxed for 24 h. Filtration followed by
concentration in vacuo and column chromatography (isohex-
ane/ethyl acetate, 9:1, 8:2, 7:3) yielded 15.2 g (98%) of the title
compound as a white solid: mp 85-87 °C. (+)-FAB-MS: 518
(MH+). 13C NMR: δ ) 13.8, 27.3, 28.0, 41.3, 45.0, 60.8, 69.2,
76.7, 78.8, 112.5, 113.6, 114.7, 127.2, 127.5, 127.6, 127.7, 127.8,
128.3, 128.7, 129.5, 136.8, 153.8, 155.1, 158.7, 169.5. Anal.
Calcd (C31H35NO6) C, H, N.
1-(4-Hyd r oxyp ip er id in -1-yl)eth a n on e (10c). To a solu-
tion of 5.60 g (0.050 mol) of 4-hydroxypiperidine in 100 mL of
methanol was added 18.8 mL (0.200 mol) of acetic acid
anhydride dropwise at 5 °C. After stirring for 72 h at room
temperature the volatiles were removed in vacuo and the
residue was recrystallized from diethyl ether to give 4.10 g
(0.029 mol; 58.0%) of pure 10c as a white solid: mp 70-73
7-[(E t h oxyca r b on yl)(4-h yd r oxyp h en yl)m et h oxy]-3,4-
d ih yd r o-1H -isoqu in olin e-2-ca r b oxylic Acid ter t-Bu t yl
Ester (6). 5 (10.8 g, 0.020 mol) was dissolved in 200 mL of
ethyl acetate and hydrogenated for 3 h at room temperature
using 2.0 g of palladium on charcoal (10%) as catalyst.

4990 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25
Kucznierz et al.
°C. El-MS: 143 (M+). 1H NMR: δ ) 1.13-1.42 (m, 2H), 1.71
(m, 2H), 2.00 (s, 3H), 2.97 (t, 1H), 3.12 (t, 1H), 3.67 (m, 2H),
3.88 (m, 1H), 4.72 (d, 1H). 13C NMR: δ ) 21.2, 33.9, 34.6,
38.4, 43.3, 65.6, 167.9. Anal. Calcd (C7H13NO2) C, H, N.
3(R)-Hyd r oxyp yr r olid in e-1-ca r boxylic Acid Allyl Ester
(10e). Prepared according to the procedure used for 10a : yield
88%; colorless oil. EI-MS: 171 (M+). 1H NMR: δ ) 1.82 (m,
2H), 3.13-3.41 (m, 4H), 4.23 (m, 1H), 4.51 (d, 2H), 4.90 (s,
1H), 5.21 (dd, 2H), 5.92 (m, 1H). 13C NMR: δ ) 32.8, 33.6,
43.5, 44.0, 53.7, 54.3, 64.6, 68.7, 69.2, 116.6, 133.6, 153.9.
Anal. Calcd (C8H13NO3) C, H, N.
3(R)-Hyd r oxyp yr r olid in e-1-ca r boxylic Acid ter t-Bu tyl
E st er (10f). Prepared according to the procedure used for
10b: yield 99%; colorless oil. El-MS: 187 (M+). 1H NMR: δ
) 1.40 (s, 9H), 1.78 (m, 2H), 3.20 (m, 4H), 4.20 (m, 1H), 4.84
(s, 1H). 13C NMR: δ ) 28.2, 32.9, 33.6, 43.5, 43.7, 53.8, 54.0,
68.4, 69.2, 78.0, 153.6. Anal. Calcd (C9H17NO3) C, H, N.
Gen er a l P r oced u r e A. Mitsu n obu Rea ction Affor d in g
Com p ou n d s 11a -f fr om 10a -f a n d 6. Under nitrogen a
solution of 0.025 mol of diethyl azodicarboxylate in 20 mL of
tetrahydrofuran was added at 5 °C to a mixture of 0.020 mol
of phenol 6, 0.025 mol of alcohol 10, and 0.025 mol of
triphenylphosphine in 150 mL of tetrahydrofuran. After
stirring for 72 h at room temperature the volatiles were
removed in vacuo, and the residue was chromatographed on
silica gel.
7-{[4-(1-(Allyloxyca r bon yl)p ip er id in -4-yloxy)p h en yl]-
(eth oxyca r bon yl)m eth oxy}-3,4-d ih yd r o-1H-isoqu in olin e-
2-ca r boxylic Acid ter t-Bu tyl Ester (11a ). Colorless oil;
yield 90%. (+)-FAB-MS: 595 (MH+). 1H NMR: δ ) 1.14 (t,
3H), 1.40 (s, 9H), 1.55 (m, 2H), 1.92 (m, 2H), 2.68 (t, 2H), 3.25
(m, 2H), 3.50 (t, 2H), 3.70 (m, 2H), 4.11 (m, 2H), 4.41 (s, 2H),
4.52 (d, 2H), 4.61 (m, 1H), 5.23 (dd, 2H), 5.83 (s, 1H), 5.90 (m,
1H), 6.75 (m, 2H), 7.01 (m, 3H), 7.43 (m, 2H). 13C NMR: δ )
13.9, 27.9, 28.0, 30.1, 40.5, 41.4, 44.8, 60.8, 65.1, 71.5, 76.6,
78.8, 112.4, 113.6, 115.6, 116.8, 127.2, 127.5, 128.8, 129.6,
133.4, 134.7, 153.9, 154.1; 155.1, 157.2, 169.5. Anal. Calcd
(C33H42N2O8) C, H, N.
133.4, 134.7, 153.8, 155.1, 156.5, 157.1, 169.5. Anal. Calcd
(C32H40N2O8) C, H, N.
7-([4-(1-(ter t-Bu t oxyca r b on yl)p yr r olid in -3(S)-yloxy)-
p h en yl](et h oxyca r b on yl)m et h oxy}-3,4-d ih yd r o-1H -iso-
qu in olin e-2-ca r boxylic Acid ter t-Bu tyl Ester (11f). Col-
orless oil; yield 41%. EI-MS: 596 (M+).
Gen er a l P r oced u r e B. N-Boc Dep r otection Affor d in g
Com p ou n d s 12a -f fr om 11a -f. At 5 °C 50 mL of a
saturated solution of hydrogen chloride in diethyl ether was
added dropwise to a mixture of 0.010 mol of N-Boc-protected
compound 11 in 50 mL of diethyl ether and the reaction
mixture stirred for 5 h at 5 °C. The precipitated product
(hydrochloride) was separated by filtration, washed with
diethyl ether several times, and dried in vacuo.
4-{4-[(Eth oxyca r bon yl)(1,2,3,4-tetr a h yd r o-isoqu in olin -
7-yloxy)m eth yl]p h en oxy}p ip er id in e-1-ca r boxylic Acid
Allyl Ester Hyd r och lor id e (12a ). White solid; yield 70%;
mp 132 °C. (+)-FAB-MS: 495 (MH+). 1H NMR: δ ) 1.15 (t,
3H), 1.60 (m, 2H), 1.95 (m, 2H), 2.98 (t, 2H), 3.33 (m, 4H),
3.72 (m, 2H), 4.16 (m, 4H), 4.55 (m, 3H), 5.23 (dd, 2H), 5.82
(s, 1H), 5.90 (m, 1H), 6.85 (m, 2H), 7.02 (m, 3H), 7.39 (m, 2H),
9.70 (s, 2H). 13C NMR: δ ) 13.9, 23.9, 30.3, 40.7, 43.4, 43.5,
61.0, 65.2, 71.6, 76.7, 113.2, 114.7, 115.8, 116.9, 124.9, 127.5,
128.9, 129.9, 130.1, 133.5, 154.2; 155.4, 157.4, 169.5. Anal.
Calcd (C28H35ClN2O6) C, H, Cl, N.
[4-(P ip er id in -4-yloxy)p h en yl](1,2,3,4-t et r a h yd r o-iso-
qu in olin -7-yloxy)a cetic Acid Eth yl Ester Dih yd r och lo-
r id e (12b). White solid; yield 72%; mp 215-222 °C. EI-MS:
410 (M+). 1H NMR: δ ) 1.13 (t, 3H), 1.89 (m, 2H), 2.11 (m,
2H), 2.92 (t, 2H), 3.06 (m, 2H), 3.18 (m, 2H), 3.30 (t, 2H), 4.11
(m, 4H), 4.68 (m, 1H), 5.88 (s, 1H), 6.86 (m, 2H), 7.02 (d, 2H),
7.10 (d, 1H), 7.42 (d, 2H), 9.40 (s, 2H), 9.80 (s, 2H). 13C NMR:
δ ) 13.8, 23.7, 26.9, 39.5, 40.2, 43.3, 61.0, 69.0, 76.6, 113.0,
114.5, 115.7, 124.8, 127.7, 128.8, 129.7, 129.9, 155.2; 157.0,
169.3. Anal. Calcd (C24H32Cl2N2O4) C, H, Cl, N.
[4-(1-Acetylp ip er id in -4-yloxy)p h en yl](1,2,3,4-tetr a h y-
d r o-isoqu in olin -7-yloxy)a cetic Acid Eth yl Ester Hyd r o-
ch lor id e (12c). Yellow oil; yield 97%. (+)-FAB-MS: 453
(MH+).
(1,2,3,4-Tetr ah ydr o-isoqu in olin -7-yloxy)[4-(tetr ah ydr o-
p yr a n -4-yloxy)p h en yl]a cetic Acid Eth yl Ester Hyd r o-
ch lor id e (12d ). Yellow solid; yield 99%. (+)-FAB-MS: 412
(MH+). 1H NMR: δ ) 1.16 (t, 3H), 1.59 (m, 2H), 1.98 (m, 2H),
2.91 (t, 2H), 3.38 (m, 4H), 3.85 (m, 2H), 4.11 (m, 4H), 4.58 (m,
1H), 5.85 (s, 1H), 6.82 (m, 2H), 6.99 (d, 2H), 7.09 (d, 1H), 7.42
(d, 2H), 9.61 (s, 2H). 13C NMR: δ ) 14.0, 24.0, 31.7, 40.6,
43.5, 61.1, 64.6, 71.3, 76.8, 113.2, 114.7, 115.8, 124.9, 127.4,
7-{[4-(1-(ter t-Bu toxycar bon yl)piper idin -4-yloxy)ph en yl]-
(eth oxyca r bon yl)m eth oxy}-3,4-d ih yd r o-1H-isoqu in olin e-
2-ca r boxylic Acid ter t-Bu tyl Ester (11b). Light yellow oil;
yield 75%. EI-MS: 610 (M+).
7-{[4-(1-Acetylp ip er id in -4-yloxy)p h en yl](eth oxyca r bo-
n yl)m et h oxy}-3,4-d ih yd r o-1H -isoq u in olin e-2-ca r b oxyl-
ic Acid ter t-Bu tyl Ester (11c). White solid; yield 91%. (+)-
FAB-MS: 553 (MH+). 1H NMR: δ ) 1.13 (t, 3H), 1.41 (s, 9H),
1.42-1.69 (m, 2H), 1.89 (m, 2H), 2.02 (s, 3H), 2.68 (t, 2H), 3.21
(m, 1H), 3.31 (m, 1H), 3.50 (t, 2H), 3.62 (m, 1H), 3.80 (m, 1H),
4.11 (m, 2H), 4.42 (s, 2H), 4.62 (m, 1H), 5.84 (s, 1H), 6.77 (m,
2H), 7.01 (m, 3H), 7.42 (d, 2H). 13C NMR: δ ) 13.9, 21.2, 27.3,
28.0, 30.1, 30.8, 37.9, 42.0, 42.8, 45.5, 60.9, 71.7, 76.7, 78.8,
112.5, 114.5, 115.7, 127.2, 127.5, 128.8, 129.5, 133.2, 153.8,
155.1; 157.3, 167.9, 169.5. Anal. Calcd (C31H40N2O7) C, H,
N.
7-{(Eth oxyca r bon yl)[4-(tetr a h yd r o-p yr a n -4-yloxy)p h e-
n yl]m et h oxy}-3,4-d ih yd r o-1H -isoq u in olin e-2-ca r b oxyl-
ic Acid ter t-Bu tyl Ester (11d ). Colorless oil; yield 58%. EI-
MS: 511 (M+). 1H NMR: δ ) 1.12 (t, 3H), 1.41 (s, 9H), 1.59
(m, 2H), 1.99 (m, 2H), 2.66 (t, 2H), 3.49 (m, 4H), 3.84 (m, 2H),
4.11 (m, 2H), 4.43 (s, 2H), 4.59 (m, 1H), 5.82 (s, 1H), 6.75 (m,
2H), 7.01 (m, 3H), 7.42 (d, 2H). 13C NMR: δ ) 14.0, 28.0, 28.1,
31.7, 40.6, 43.6, 61.0, 64.5, 71.3, 76.8, 79.0, 112.8, 113.8, 115.8,
127.4, 127.6, 128.9, 129.6, 129.7, 153.9, 155.3; 157.4, 169.7.
Anal. Calcd (C29H37NO7) C, H, N.
7-{[4-(1-(Allyloxyca r bon yl)p yr r olid in -3(S)-yloxy)p h e-
n yl](eth oxyca r bon yl)m eth oxy}-3,4-d ih yd r o-1H-isoqu in o-
lin e-2-ca r boxylic Acid ter t-Bu tyl Ester (11e). Colorless
oil; yield 91%. (+)-LSIMS: 579.9 (MH+). 1H NMR: δ ) 1.12
(m, 3H), 1.42 (s, 9H), 2.12 (m, 2H), 2.68 (t, 2H), 3.50 (m, 6H),
4.12 (m, 2H), 4.43 (s, 2H), 4.52 (d, 2H), 5.02 (m, 1H), 5.22 (dd,
2H), 5.85 (s, 1H), 5.92 (m, 1H), 6.76 (m, 2H), 7.02 (m, 3H),
7.45 (d, 2H). 13C NMR: δ ) 13.9, 14.6, 27.3, 28.0, 29.8, 30.8,
41.4, 43.5, 44.1, 44.8, 50.8, 51.4, 60.3, 60.9, 64.8, 75.1, 76.0,
77.0, 78.8, 112.6, 113.7, 115.4, 116.8, 127.3, 127.9, 128.8, 129.5,
129.0, 129.9, 130.1, 155.4; 157.4, 169.5. Anal. Calcd (C24H30
ClNO5) C, H, Cl, N.
-
3(S)-{4-[(Eth oxyca r bon yl)(1,2,3,4-tetr a h yd r o-isoqu in o-
lin -7-yloxy)m eth yl]ph en oxy}pyr r olidin e-1-car boxylic Acid
Allyl Ester Hyd r och lor id e (12e). Colorless oil; yield 99%.
EI-MS: 480 (M+). 1H NMR: δ ) 1.15 (m, 3H), 2.10 (m, 2H),
2.90 (t, 2H), 3.20-3.70 (m, 6H), 4.05 (m, 2H), 4.15 (d, 2H),
4.50 (s, 2H), 5.05 (m, 1H), 5.20 (dd, 2H), 5.83 (s, 1H), 5.91 (m,
1H), 6.82 (m, 2H), 6.98 (d, 2H), 7.11 (d, 1H), 7.44 (d, 2H), 9.68
(s, 2H). 13C NMR: δ ) 13.9, 14.5, 23.8, 29.9, 30.7, 43.4, 43.5,
44.1, 46.0, 51.0, 51.6, 60.3, 60.9, 64.8, 75.1, 76.0, 76.6, 113.1,
114.6, 115.4, 116.8, 124.8, 127.7, 128.9, 129.8, 130.0, 133.4,
153.7, 155.3, 157.2, 169.3.
[4-(P yr r olid in -3(S)-yloxy)p h en yl](1,2,3,4-t et r a h yd r o-
isoqu in olin -7-yloxy)a cetic Acid Eth yl Ester Dih yd r o-
ch lor id e (12f). Light brownish solid; yield 46%; mp 50 °C.
(+)-FAB-MS: 397 (MH+). 1H NMR: δ ) 1.12 (t, 3H), 2.18 (m,
2H), 2.92 (t, 2H), 3.30-3.60 (m, 6H), 4.11 (m, 4H), 5.12 (m,
1H), 5.90 (s, 1H), 6.88 (m, 2H), 7.01 (d, 2H), 7.12 (d, 1H), 7.47
(d, 2H), 9.71 (s, 2H), 9.82 (s, 2H). 13C NMR: δ 13.8, 23.8, 30.6,
40.7, 43.1, 43.3, 49.3, 61.0, 75.4, 76.5, 113.1, 114.9, 115.6, 124.7,
128.1, 128.9, 129.7, 129.9, 155.2; 156.7, 169.3.
Gen er a l P r oced u r e C. Gu a n yla tion of Tetr a h yd r o-
isoqu in olin es. To a stirred mixture of the appropriate
tetrahydro-isoquinoline hydrochloride (0.005 mol) and 1H-
pyrazole-1-carboxamidine hydrochloride (0.010 mol) in 5 mL
of N,N-dimethylformamide was added 5.2 mL (0.030 mol) of

Tetrahydro-isoquinoline-Based fXa Inhibitors
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25 4991
diisopropylethylamnine under nitrogen at 5 °C. Stirring was
continued at room temperature for 24 h. Diethyl ether was
added to afford precipitation of the crude product which was
collected, washed with ether, and dissolved in water and the
aqueous solution adjusted to pH 3. Preparative HPLC chro-
matography (H2O, pH 3; H2O/CH3OH, 7:3, pH 3) afforded pure
guanidine hydrochloride.
4-{4-[(2-Ca r ba m im idoyl-1,2,3,4-tetr a h yd r o-isoqu in olin -
7-yloxy)(eth oxyca r bon yl)m eth yl]p h en oxy}p ip er id in e-1-
ca r boxylic Acid Allyl Ester Hyd r och lor id e (13). Colorless
oil; yield 94%. (+)-FAB-MS: 537 (MH+). 1H NMR: δ ) 1.17
(t, 3H), 1.60 (m, 2H), 1.92 (m, 2H), 2.82 (t, 2H), 3.30 (m, 2H),
3.58 (t, 2H), 3.69 (m, 2H), 4.15 (m, 2H), 4.58 (m, 5H), 5.20 (dd,
2H), 5.85 (s, 1H), 5.92 (m, 1H), 6.75 (s, 1H), 6.85 (d, 2H), 7.00
(d, 2H), 7.13 (d, 1H), 7.47 (d, 2H), 7.70 (4, 2H). 13C NMR: δ
) 13.9, 26.9, 30.3, 40.7, 43.2, 46.6, 61.1, 65.2, 71.6, 76.9, 112.8,
114.2, 115.8, 116.9, 127.2, 127.6, 129.0, 129.4, 133.2, 133.5,
154.2; 155.5, 156.4, 157.4, 169.6. Anal. Calcd (C29H37ClN4O6)
C, H, Cl, N.
[4-(1-Ca r ba m im id oyl-p ip er id in -4-yloxy)p h en yl](2-ca r -
ba m im id oyl-1,2,3,4-tetr a h yd r o-isoqu in olin -7-yloxy)a ce-
tic Acid Eth yl Ester Dih yd r och lor id e (14). White solid;
yield 78%; mp 120 °C. (+)-FAB-MS: 495 (MH+). 1H NMR: δ
) 1.15 (t, 3H), 1.66 (m, 2H), 2.03 (m, 2H), 2.86 (t, 2H), 3.41
(m, 2H), 3.63 (t, 2H), 3.70 (m, 2H), 4.15 (m, 2H), 4.59 (s, 2H),
4.70 (m, 1H), 5.83 (s, 1H), 6.75 (s, 1H), 6.85 (d, 1H), 7.06 (d,
2H), 7.17 (d, 1H), 7.49 (d, 2H), 7.74 (s, 4H), 7.79 (s, 4H). 13C
NMR: δ ) 13.9, 26.7, 29.8, 42.3, 43.0, 46.5, 61.0, 70.6, 76.8,
112.6, 114.0; 115.7, 127.0, 127.6, 128.8, 129.3, 133.0, 155.3;
156.1, 156.3, 157.2, 169.5. Anal. Calcd (C26H36Cl2N6O4) C, H,
Cl, N.
[4-(1-Acetylpiper idin -4-yloxy)ph en yl](2-car bam im idoyl-
1,2,3,4-tetr a h yd r o-isoqu in olin -7-yloxy)a cetic Acid Eth yl
Ester Hyd r och lor id e (15). Yellow solid; yield 43%; mp 103
°C. (+)-FAB-MS: 495 (MH+). 1H NMR: δ ) 1.13 (t, 3H), 1.50
(m, 1H), 1.61 (m, 1H), 1.86 (m, 1H), 1.92 (m, 1H), 2.02 (s, 3H),
2.82 (t, 2H), 3.23 (m, 1H), 3.48 (m, 1H), 3.61 (t, 2H), 3.69 (m,
1H), 3.82 (m, 1H), 4.12 (m, 2H), 4.56 (s, 2H), 4.61 (m, 1H),
5.83 (s, 1H), 6.72 (s, 1H), 6.82 (d, 1H), 7.00 (d, 2H), 7.11 (d,
1H), 7.45 (d, 2H), 7.72 (s, 4H). 13C NMR: δ ) 14.0, 21.3, 26.9,
30.2, 30.9, 38.1, 43.0, 43.2, 46.6, 61.1, 71.8, 76.9, 112.7, 114.2,
115.9, 127.2, 127.5, 129.0, 129.4, 133.2, 155.4, 156.4; 157.4,
168.1, 169.6. Anal. Calcd (C27H35ClN4O5) C, H, N.
d r och lor id e (18). Prepared from 15 using the procedure
described for 17: white solid; yield 53%; mp 102 °C. (+)-FAB-
MS: 467 (MH+). 1H NMR: δ ) 1.55 (m, 2H), 1.89 (m, 2H),
2.02 (s, 3H), 2.81 (t, 2H), 3.28 (m, 2H), 3.58 (t, 2H), 3.64 (m,
1H), 3.79 (m, 1H), 4.52 (s, 2H), 4.60 (m, 1H), 5.71 (s, 1H), 6.70
(s, 1H), 6.81 (d, 1H), 6.99 (d, 2H), 7.11 (d, 1H), 7.45 (d, 2H),
7.72 (s, 4H). 13C NMR: δ ) 21.2, 26.7, 30.1, 30.8, 37.9, 42.8,
43.0, 46.5, 71.7, 76.8, 112.4, 114.0, 115.7, 126.8, 128.1, 128.8,
129.2, 133.0, 155.6, 156.3; 157.2, 168.0, 170.8. Anal. Calcd
(C25H31ClN4O5) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)[4-(tetr a h yd r o-p yr a n -4-yloxy)p h en yl]a cetic Acid
Hyd r och lor id e (19). Prepared from 16 using the procedure
described for 17: pale yellow solid; yield 25%; mp 112 °C. (+)-
FAB-MS: 426 (MH+). 1H NMR: δ ) 1.59 (m, 2H), 1.97 (m,
2H), 2.82 (t, 2H), 3.48 (m, 2H), 3.58 (t, 2H), 3.84 (m, 2H), 4.52
(s, 2H), 4.59 (m, 1H), 5.70 (s, 1H), 6.72 (s, 1H), 6.84 (d, 1H),
6.99 (d, 2H), 7.13 (d, 1H), 7.42 (d, 2H), 7.71 (s, 4H). 13C NMR:
δ ) 26.9, 31.7, 43.2, 46.6, 64.5, 71.3, 77.0, 112.5, 114.1, 115.7,
126.9, 128.1, 128.9, 129.4, 133.0, 155.7; 156.4, 157.2, 171.1.
Anal. Calcd (C23H28ClN3O5) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)[4-(p ip er id in -4-yloxy)p h en yl]a cetic Acid Eth yl Es-
t er Dih yd r och lor id e (20). Under nitrogen 720 mg of
tetrakis(triphenylphosphine)palladium was added at 5 °C to
a solution of 1.90 g (3.32 mmol) of 13 and 4.20 g (33.20 mmol)
of dimedone in 160 mL of tetrahydrofuran, and the mixture
was stirred for 48 h at room temperature. The solvent was
pumped off, and 75 mL of 0.1 N aqueous hydrogen chloride
solution was added followed by filtration in order to remove
the precipitated material. The aqueous solution was washed
with ethyl acetate and diethyl ether, concentrated, and
adjusted to pH 3. Preparative HPLC chromatography (H2O,
pH 3; H2O/CH3CN, 75:25, pH 3) afforded 1.70 g (97%) of the
title compound as a yellow solid: mp 130 °C. (+)-FAB-MS:
453 (MH+). 1H NMR: δ ) 1.11 (t, 3H), 1.90 (m, 2H), 2.11 (m,
2H), 2.81 (t, 2H), 3.07 (m, 2H), 3.19 (m, 2H), 3.57 (t, 2H), 4.12
(m, 2H), 4.52 (s, 2H), 4.70 (m, 1H), 5.85 (s, 1H), 6.72 (s, 1H),
6.83 (d, 1H), 7.04 (d, 2H), 7.12 (d, 1H), 7.46 (d, 2H), 7.71 (s,
4H), 9.33 (s, 2H). 13C NMR: δ ) 14.0, 27.0, 30.7, 40.6, 43.2,
46.6, 61.1, 69.0, 76.9, 112.7, 114.2, 115.8, 127.2, 127.8, 129.0,
129.4, 133.2, 155.4, 156.4, 157.1, 169.6. Anal. Calcd (C25H34
Cl2N4O4) C, H, Cl, N.
-
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)[4-(tetr a h yd r o-p yr a n -4-yloxy)p h en yl]a cetic Acid
Eth yl Ester Hyd r och lor id e (16). Light yellow solid; yield
42%; mp 95 °C. (+)-FAB-MS: 454 (MH+); 1H NMR: δ ) 1.12
(t, 3H), 1.58 (m, 2H), 1.97 (m, 2H), 2.82 (t, 2H), 3.48 (m, 2H),
3.59 (t, 2H), 3.85 (m, 2H), 4.11 (m, 2H), 4.52 (s, 2H), 4.59 (m,
1H), 5.85 (s, 1H), 6.74 (s, 1H), 6.85 (d, 1H), 7.01 (d, 2H), 7.14
(d, 1H), 7.42 (d, 2H), 7.73 (s, 4H). 13C NMR: δ ) 14.0, 26.8,
31.7, 43.1, 46.6, 61.1, 64.6, 71.3, 76.9, 112.7, 114.2, 115.8, 127.2,
127.5, 129.0, 129.4, 133.2, 155.5; 156.4, 157.4, 169.6. Anal.
Calcd (C25H32ClN3O5) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)[4-(p ip er id in -4-yloxy)p h en yl]a cetic Acid Dih yd r o-
ch lor id e (21). Prepared from 20 using the procedure de-
scribed for 17: light yellow solid; yield 89%; mp 157 °C. (+)-
FAB-MS: 425 (MH+). 1H NMR: δ ) 1.81 (m, 2H), 2.08 (m,
2H), 2.80 (t, 2H), 3.03 (m, 2H), 3.13 (m, 2H), 3.57 (t, 2H), 4.49
(s, 2H), 4.61 (m, 1H), 5.46 (s, 1H), 6.69 (s, 1H), 6.80 (d, 1H),
7.00 (d, 2H), 7.09 (d, 1H), 7.43 (d, 2H), 7.87 (s, 4H), 9.50 (s,
2H). 13C NMR: δ ) 26.9, 30.6, 43.1, 43.8, 46.6, 69.0, 78.9,
112.8, 114.2, 115.5, 126.2, 128.7, 129.1, 130.0, 132.8, 156.0,
156.1, 156.3, 172.0. Anal. Calcd (C23H30Cl2N4O4) C, H, Cl, N.
[4-(1-Ca r ba m im id oyl-p ip er id in -4-yloxy)p h en yl](2-ca r -
ba m im id oyl-1,2,3,4-tetr a h yd r o-isoqu in olin -7-yloxy]a ce-
tic Acid Dih yd r och lor id e (17). 14 (567 mg, 1.0 mmol) was
dissolved in a mixture of 20 mL of water and 20 mL of ethanol
and 1 N aqueous sodium hydroxide solution (4 mL) added at
5 °C while stirring. After stirring for another hour at room
temperature the solution was adjusted to pH 3 by adding 2 N
aqueous hydrochloric acid and concentrated. The crude prod-
uct was purified using reverse-phase HPLC chromatography
(H2O, pH 3; H2O/CH3CN, 7:3, pH 3) to give 400 mg (74%) of
the title acid as a white solid: mp 95 °C. (+)-FAB-MS: 467
(MH+). 1H NMR: δ ) 1.60 (m, 2H), 1.95 (m, 2H), 2.78 (t, 2H),
3.40 (m, 2H), 3.61 (t, 2H), 3.67 (m, 2H), 4.54 (s, 2H), 4.63 (m,
1H), 5.40 (s, 1H), 6.70 (s, 1H), 6.79 (d, 1H), 6.96 (d, 2H), 7.08
(d, 1H), 7.44 (d, 2H), 7.89 (s, 8H). 13C NMR: δ ) 26.9, 30.0,
42.4, 43.1, 46.6, 70.7, 78.5, 112.4, 113.8, 115.5, 126.0, 128.7,
128.9, 130.4, 132.8, 155.5; 156.3, 156.5, 157.6, 172.6. Anal.
Calcd (C24H32Cl2N6O4) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy){4-[1-(1-im in oe t h yl)p ip e r id in -4-yloxy]p h e n yl}-
a cetic Acid Eth yl Ester Dih yd r och lor id e (22). Under
nitrogen triethylamine (2.2 mL, 0.016 mol) was added at 5 °C
to a stirred mixture of 1.05 g (0.002 mol) of 20 and 0.50 g (0.004
mol) of acetimidic acid ethyl ester hydrochloride in 50 mL of
ethanol. Stirring was continued for 48 h at room temperature
followed by evaporation of the solvent. The residue was
dissolved in water (20 mL) and the solution adjusted to pH 3
and chromatographed (HPLC: H2O, pH 3; H2O/CH3CN, 8:2,
pH 3) to give 0.60 g (53%) of the title compound as a colorless
oil. (+)-FAB-MS: 494 (MH+). 1H NMR: δ ) 1.17 (t, 3H), 1.75
(m, 2H), 2.08 (m, 2H), 2.36 (s, 3H), 2.85 (t, 2H), 3.46-3.96 (m,
6H), 4.13 (m, 2H), 4.58 (s, 2H), 4.77 (m, 1H), 5.85 (s, 1H), 6.75
(s, 1H), 6.84 (d, 1H), 7.06 (d, 2H), 7.15 (d, 1H), 7.48 (d, 2H),
7.79 (s, 4H), 9.00 (s, 1H), 9.56 (s, 1H). 13C NMR: δ ) 13.9,
18.3, 26.7, 29.2, 30.0, 42.5, 43.0, 44.7, 46.5, 61.0, 70.0, 76.7,
112.6, 114.0, 115.7, 127.0, 127.6, 128.9, 129.3, 133.1, 155.3;
156.3, 157.1, 162.8, 169.4. Anal. Calcd (C27H37Cl2N5O4) C, H,
Cl, N.
[4-(1-Acetylpiper idin -4-yloxy)ph en yl](2-car bam im idoyl-
1,2,3,4-tetr a h yd r o-isoqu in olin -7-yloxy)a cetic Acid Hy-

4992 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25
Kucznierz et al.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)(4-{1-[im in o(4-m eth oxyp h en yl)m eth yl]p ip er id in -
4-yloxy}p h en yl)a cetic Acid Eth yl Ester Dih yd r och lor id e
(23). Prepared from 4-methoxybenzimidic acid ethyl ester
hydrochloride (obtained from 4-methoxybenzonitrile, ethanol,
and gaseous HCl) and 20 according to the procedure described
for compound 22: white solid; mp 165 °C; yield 58%. (+)-FAB-
MS: 586 (MH+). 1H NMR: δ ) 1.11 (t, 3H), 1.71 (m, 1H),
1.88 (m, 1H), 2.00 (m, 1H), 2.20 (m, 1H), 2.82 (t, 2H), 3.40 (m,
1H), 3.53 (m, 1H), 3.58 (t, 2H), 3.78 (m, 1H), 3.87 (s, 3H), 3.99
(m, 1H), 4.10 (m, 2H), 4.57 (s, 2H), 4.78 (m, 1H), 5.82 (s, 1H),
6.72 (s, 1H), 6.82 (d, 1H), 7.03 (d, 2H), 7.12 (m, 3H), 7.45 (d,
2H), 7.57 (d, 2H), 7.78 (s, 4H), 9.43 (s, 1H), 9.58 (s, 1H). 13C
NMR: δ ) 13.6, 26.7, 29.3, 30.2, 43.0, 43.8, 46.4, 46.9, 55.5,
61.0, 70.2, 76.7, 112.6, 114.0, 114.3, 115.8, 121.0, 127.0, 127.7,
128.9, 129.3, 130.4, 133.1, 155.3; 156.3, 157.1, 162.0, 163.6,
169.5. Anal. Calcd (C33H41Cl2N5O5) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy){4-[1-(1-im in op r op yl)p ip er id in -4-yloxy]p h en yl}-
a cetic Acid Eth yl Ester Dih yd r och lor id e (24). Prepared
from propionimidic acid ethyl ester hydrochloride (obtained
from propionitrile, ethanol, and gaseous HCl) and 20 according
to the procedure described for compound 22: white solid; mp
64-66 °C; yield 53%. (+)-FAB-MS: 508 (MH+). 1H NMR: δ
) 1.14 (t, 3H), 1.17 (t, 3H), 1.76 (m, 2H), 2.07 (m, 2H), 2.67 (q,
2H), 2.84 (t, 2H), 3.50-3.99 (m, 6H), 4.12 (m, 2H), 4.60 (s, 2H),
4.78 (m, 1H), 5.88 (s, 1H), 6.78 (s, 1H), 6.87 (d, 1H), 7.04 (d,
2H), 7.13 (d, 1H), 7.49 (d, 2H), 7.87 (s, 4H), 9.09 (s, 1H), 9.51
(s, 1H). 13C NMR: δ ) 11.1, 13.9, 24.5, 26.7, 29.3, 30.5, 42.8,
43.0, 44.4, 46.5, 61.0, 70.0, 76.7, 112.6, 114.0, 115.8, 127.0,
127.7, 128.9, 129.3, 133.1, 155.3; 156.3, 157.1, 166.7, 169.5.
Anal. Calcd (C28H39Cl2N5O4) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy){4-[1-(1-im in oe t h yl)p ip e r id in -4-yloxy]p h e n yl}-
a cetic Acid Dih yd r och lor id e (25). Prepared from 22 using
the procedure described for 17: white solid; yield 74%; mp 162
°C. (+)-FAB-MS: 466 (MH+). 1H NMR: δ ) 1.73 (m, 2H),
2.02 (m, 2H), 2.31 (s, 3H), 2.78 (t, 2H), 3.58 (t, 2H), 3.67 (m,
2H), 3.81 (m, 2H), 4.53 (s, 2H), 4.68 (m, 1H), 5.48 (s, 1H), 6.70
(s, 1H), 6.80 (d, 1H), 6.95 (d, 2H), 7.06 (d, 1H), 7.46 (d, 2H),
7.89 (s, 4H), 9.00 (s, 1H), 9.50 (s, 1H). 13C NMR: δ ) 18.4,
26.9, 29.3, 30.1, 42.6, 43.2, 44.8, 46.9, 70.1, 78.5, 112.5, 113.9,
115.6, 126.1, 128.8, 128.9, 129.3, 132.9, 156.3; 156.5, 156.6,
162.9, 172.1. Anal. Calcd (C25H33Cl2N5O4) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)(4-{1-[im in o(4-m eth oxyp h en yl)m eth yl]p ip er id in -
4-yloxy}p h en yl)a cetic Acid Dih yd r och lor id e (26). Pre-
pared from 23 using the procedure described for 17: white
solid; yield 72%; mp 223 °C. (+)-LSIMS: 558.2 (MH+). 1H
NMR: δ ) 1.72 (m, 1H), 1.89 (m, 1H), 2.00 (m, 1H), 2.18 (m,
1H), 2.80 (t, 2H), 3.40 (m, 1H), 3.55 (m, 1H), 3.60 (t, 2H), 3.79
(m, 1H), 3.83 (s, 3H), 3.99 (m, 1H), 4.55 (s, 2H), 4.78 (m, 1H),
5.82 (s, 1H), 6.71 (s, 1H), 6.82 (d, 1H), 7.03 (d, 2H), 7.12 (m,
3H), 7.48 (d, 2H), 7.59 (d, 2H), 7.82 (s, 4H), 9.45 (s, 1H), 9.60
(s, 1H). 13C NMR: δ ) 26.7, 29.3, 30.2, 43.0, 43.8, 46.5, 46.9,
55.5, 70.1, 76.7, 112.4, 114.0,.114.3, 115.7, 121.0, 126.7, 128.3,
128.8, 129.3, 130.4, 133.0, 155.5; 156.3, 156.9, 162.0, 163.6,
170.7. Anal. Calcd (C31H37Cl2N5O5) C, H, Cl, N.
from 12f according to general procedure C: pale yellow solid;
yield 53%; mp 90 °C. (+)-FAB-MS: 481 (MH+). 1H NMR: δ
) 1.14 (t, 3H), 2.23 (m, 2H), 2.85 (t, 2H), 3.60 (m, 6H), 4.16
(m, 2H), 4.51 (s, 2H), 5.20 (m, 1H), 5.88 (s, 1H), 6.75 (s, 1H),
6.85 (d, 1H), 7.02 (d, 2H), 7.15 (d, 1H), 7.49 (d, 2H), 7.59 (s,
4H), 7.82 (s, 4H). 13C NMR: δ ) 13.9, 26.7, 30.0, 43.0, 45.2,
46.5, 52.4, 61.0, 75.3, 76.7, 112.6, 114.0, 115.5, 127.1, 128.0,
128.9, 129.3, 133.1, 154.9, 155.2; 156.3, 156.9, 169.4. Anal.
Calcd (C25H34Cl2N6O4) C, H, Cl, N.
[4-(1-Ca r ba m im id oyl-p yr r olid in -3(S)-yloxy)p h en yl](2-
ca r ba m im id oyl-1,2,3,4-tetr a h yd r o-isoqu in olin -7-yloxy)-
a cetic Acid Dih yd r och lor id e (29). Prepared from 28 using
the procedure described for 17: light brownish solid; yield 69%;
mp >155 °C dec. (+)-FAB-MS: 453 (MH+). 1H NMR: δ )
2.27 (m, 2H), 2.85 (t, 2H), 3.59 (m, 6H), 4.58 (s, 2H), 5.20 (m,
1H), 5.78 (s, 1H), 6.73 (s, 1H), 6.85 (d, 1H), 7.02 (d, 2H), 7.14
(d, 1H), 7.49 (d, 2H), 7.51 (s, 4H), 7.74 (s, 4H). 13C NMR: δ )
26.7, 30.0, 43.0, 45.1, 46.5, 52.3, 75.2, 76.7, 112.4, 114.0, 115.4,
126.8, 128.6, 128.8, 129.2, 133.0, 154.8, 155.5; 156.3, 156.7,
170.7. Anal. Calcd (C23H30Cl2N6O4) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)[4-(p yr r olid in -3(S)-yloxy)p h en yl]a cetic Acid Eth yl
Ester Dih yd r och lor id e (30). Tetrakis(triphenylphosphine)-
palladium (333 mg, 0.0003 mol) was added to a stirred mixture
of 27 (1.50 g, 0.0029 mol) and tributyltin hydride (1.56 mL,
0.0058 mol) in 300 mL of dichloromethane at 5 °C. Stirring
was continued at 5 °C for 3 h followed by extraction with
aqueous hydrochloric acid (0.1 N), separation of precipitated
material by filtration, and concentration of the combined
aqueous extracts affording 1.37 g (0.0027 mol, 93%) of 30 as a
white solid: mp >170 °C dec. (+)-FAB-MS: 439 (MH+). 1H
NMR: δ ) 1.15 (t, 3H), 2.15 (m, 2H), 2.83 (t, 2H), 3.32 (m,
4H), 3.60 (t, 2H), 4.15 (m, 2H), 4.56 (s, 2H), 5.13 (m, 1H), 5.87
(s, 1H), 6.76 (s, 1H), 6.87 (d, 1H), 7.02 (d, 2H), 7.14 (d, 1H),
7.49 (d, 2H), 7.74 (s, 4H), 9.70 (s, 1H), 10.00 (s, 1H). 13C
NMR: δ ) 14.0, 26.8, 30.6, 43.2, 43.3, 46.6, 49.5, 61.1, 75.6,
76.8, 112.8, 114.2, 115.8, 127.2, 128.3, 129.0, 129.4, 133.2,
155.4, 156.4, 156.9, 169.6. Anal. Calcd (C24H32Cl2N4O4) C, H,
Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)[4-(p yr r olid in -3(S)-yloxy)p h en yl]a cetic Acid Di-
h yd r och lor id e (31). Prepared from 30 using the procedure
described for 17: pale yellow solid; yield 31%; mp 100-105
°C. (+)-FAB-MS: 411 (MH+). 1H NMR: δ ) 2.16 (m, 2H),
2.83 (t, 2H), 3.38 (m, 4H), 3.60 (t, 2H), 4.53 (s, 2H), 5.16 (m,
1H), 5.73 (s, 1H), 6.71 (s, 1H), 6.82 (d, 1H), 7.00 (d, 2H), 7.13
(d, 1H), 7.49 (d, 2H), 7.66 (s, 4H), 9.56 (s, 1H), 9.81 (s, 1H).
13C NMR: δ ) 26.7, 30.4, 43.0, 43.2, 46.5, 49.5, 75.4, 76.7,
112.4, 114.0, 115.6, 126.8, 128.7, 128.8, 129.2, 132.9, 155.5,
156.2, 156.5, 170.8. Anal. Calcd (C22H28Cl2N4O4) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy){4-[1-(1-im in oeth yl)p yr r olid in -3(S)-yloxy]p h en yl}-
a cetic Acid Eth yl Ester Dih yd r och lor id e (32). Prepared
from 30 using the procedure described for 22: yellowish solid;
yield 77%; mp >130 °C dec. (+)-FAB-MS: 480 (MH+). 1H
NMR: δ ) 1.16 (t, 3H), 2.23 (m, 2H), 2.30 (d, 3H), 2.82 (t,
2H), 3.60 (m, 6H), 4.14 (m, 2H), 4.56 (s, 2H), 5.21 (m, 1H),
5.88 (s, 1H), 6.72 (s, 1H), 6.84 (d, 1H), 7.01 (d, 2H), 7.13 (d,
1H), 7.48 (d, 2H), 7.79 (s, 4H), 8.67 (d, 1H), 9.52 (d, 1H). 13C
NMR: δ ) 14.0, 18.5, 26.8, 30.0, 43.2, 43.3, 46.6, 47.3, 61.1,
75.4, 76.8, 112.8, 114.2, 115.7, 127.2, 128.2, 129.1, 129.4, 133.2,
155.4, 156.5, 156.9, 162.9, 169.6. Anal. Calcd (C26H35Cl2N5O4)
C, H, Cl, N.
3(S)-{4-[(2-Ca r ba m im id oyl-1,2,3,4-tetr a h yd r o-isoqu in -
o l i n -7 -y l o x y )(e t h o x y c a r b o n y l )m e t h y l ]p h e n o x y }-
p yr r olid in e-1-ca r boxylic Acid Allyl Ester Hyd r och lor id e
(27). Prepared from 12e according to general procedure C:
white solid; yield 74%; mp 80-83 °C. (+)-FAB-MS: 523
(MH+). 1H NMR: δ ) 1.15 (m, 3H), 2.10 (m, 2H), 2.84 (t, 2H),
3.30-3.70 (m, 6H), 4.13 (m, 2H), 4.54 (m, 4H), 5.06 (m, 1H),
5.22 (dd, 2H), 5.84 (s, 1H), 5.92 (m, 1H), 6.72 (s, 1H), 6.84 (d,
1H), 6.99 (d, 2H), 7.12 (d, 1H), 7.47 (d, 2H), 7.71 (s, 4H). 13C
NMR: δ ) 14.0, 26.9, 29.9, 30.7, 43.1, 43.7, 44.2, 46.6, 51.0,
51.6, 61.1, 64.9, 75.2, 76.1, 76.9, 112.8, 114.2, 115.5, 116.9,
127.2, 127.8, 129.0, 129.4, 133.2, 133.6, 154.0, 155.4, 156.4,
157.3, 169.6. Anal. Calcd (C28H35ClN4O6) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy)-{4-[1-(1-im in oeth yl)p yr r olidin -3(S)-yloxy]p h en yl}-
a cetic Acid Dih yd r och lor id e (33). Prepared from 32 using
the procedure described for 17: pale yellow solid; yield 96%;
mp >180 °C dec. (+)-FAB-MS: 452 (MH+). 1H NMR: δ )
2.12 (m, 2H), 2.25 (d, 3H), 2.79 (t, 2H), 3.62 (m, 6H), 4.51 (s,
2H), 5.11 (m, 1H), 5.43 (s, 1H), 6.69 (s, 1H), 6.78 (d, 1H), 6.90
(d, 2H), 7.05 (d, 1H), 7.48 (d, 2H), 7.94 (s, 4H), 8.74 (d, 1H),
9.58 (d, 1H). 13C NMR: δ ) 18.5, 26.9, 30.0, 43.2, 43.3, 46.7,
47.1, 75.3, 78.9, 112.4, 114.1, 115.3, 126.1, 128.8, 129.2, 130.9,
[4-(1-Ca r ba m im id oyl-p yr r olid in -3(S)-yloxy)p h en yl](2-
ca r ba m im id oyl-1,2,3,4-tetr a h yd r o-isoqu in olin -7-yloxy)-
a cetic Acid Eth yl Ester Dih yd r och lor id e (28). Prepared

Tetrahydro-isoquinoline-Based fXa Inhibitors
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 25 4993
132.9, 156.1, 156.3, 156.5, 162.9, 172.3. Anal. Calcd (C24H31
Cl2N5O4) C, H, Cl, N.
-
(aPTT doubling concentrations) were determined using the
equation y ) a + b × xc, where y is the experimental
coagulation time (s), x is the concentration of the inhibitor
(µM), a is the coagulation time in the absence of the inhibitor,
and b and c are parameters which determine the shape and
the location on the x-axis of the coagulation time/concentration
curve. These parameters were determined from the experi-
mental coagulation times using a nonlinear regression with
the starting values b ) 10 and c ) 0.65. The resulting ED200
values (from quadruplicate determinations) were within (20%
of the values given in Table 1.
Th r om bin clottin g tim e (TT): citrated plasma (190 µL)
and dimethyl sulfoxide (10 µL, control sample) or the test
compound in dimethyl sulfoxide (10 µL) were incubated in a
KC10 coagulometer (Amelung, Lemgo, Germany) for 2 min at
37 °C. Coagulation was started by addition of thrombin
reagent (200 µL STA thrombin, contains 3 U/mL equine
thrombin and 0.0125 mol Ca2+/L; Diagnostica Stago/
Boehringer Mannheim GmbH, Germany). The addition of this
reagent started a stop watch, which stopped when the plasma
had coagulated. Quadruplicate determinations were per-
formed for each individual assay. The TT was 24 ( 2 s in the
control experiments; samples containing a test compound
exhibited prolonged clotting times. The TT increase (i.e., the
difference to the control experiment) in seconds was deter-
mined at concentrations of the test compound in the citrated
plasma of 500, 100, 50, 5, and 0.5 µM. ED200 values (TT
doubling concentrations) were determined using the equation
y ) a + b × xc, where y is the experimental coagulation time
(s), x is the concentration of the inhibitor (µM), a is the
coagulation time in the absence of the inhibitor, and b and c
are parameters which determine the shape and the location
on the x-axis of the coagulation time/concentration curve.
These parameters were determined from the experimental
coagulation times using a nonlinear regression with the
starting values b ) 10 and c ) 0.65. The resulting ED200
values (from quadruplicate determinations) were within (20%
of the values given in Table 1.
[4-(1-Allylp yr r olid in -3(S )-yloxy)p h e n yl](2-ca r b a m -
im idoyl-1,2,3,4-tetr ah ydr o-isoqu in olin -7-yloxy)acetic Acid
Eth yl Ester Hyd r och lor id e (34) a n d (2-Ca r ba m im id oyl-
1,2,3,4-tetr ah ydr o-isoqu in olin -7-yloxy)(4-[1-(5,5-dim eth yl-
3-oxocycloh e x-1-e n yl)p yr r olid in -3(S )-yloxy]p h e n yl}-
a cet ic Acid E t h yl E st er Hyd r och lor id e (35). Under
nitrogen 240 mg (0.0002 mol) of tetrakis(triphenylphosphine)-
palladium was added at 5 °C to 0.56 g (0.001 mmol) of 27 and
1.40 g (0.010 mmol) of dimedone in 50 mL of tetrahydrofuran
and the mixture stirred for 48 h at room temperature. The
solvent was pumped off, and 50 mL of 0.1 N aqueous hydrogen
chloride solution was added followed by filtration in order to
remove the precipitated material. The aqueous solution
washed with ethyl acetate and diethyl ether, concentrated,
adjusted to pH 3, and chromatographed (HPLC: H2O, pH 3;
H2O/CH3CN, 8:2, pH 3; H2O/CH3CN, 7:3, pH 3) yielding 98
mg (20%) of 34 as a yellow oil. EI-MS: 478 (M+). 1H NMR:
δ ) 1.14 (t, 3H), 2.12 (m, 2H), 2.82 (t, 2H), 3.26 (m, 4H), 3.60
(t, 2H), 3.82 (d, 2H), 4.12 (m, 2H), 4.54 (s, 2H), 5.17 (m, 1H),
5.48 (dd, 2H), 5.88 (s, 1H), 5.99 (m, 1H), 6.73 (s, 1H), 6.83 (d,
1H), 7.01 (d, 2H), 7.14 (d, 1H), 7.49 (d, 2H), 7.63 (s, 4H). 13C
NMR: δ ) 13.8, 26.7, 30.6, 43.2, 43.8, 46.2, 50.9, 51.0, 61.0,
74.8, 76.7, 112.7, 114.0, 115.5, 115.6, 123.8, 127.1, 128.2, 128.9,
129.3, 133.0, 155.3, 156.2, 156.7, 169.4. Anal. Calcd (C27H35
-
ClN4O4) C, H, Cl, N. Also yielded was 230 mg (40%) of 35 as
1
a white solid: mp >160 °C dec. (+)-FAB-MS: 561 (MH+). H
NMR: δ ) 1.10 (m, 9H), 2.20-2.72 (m, 6H), 2.81 (t, 2H), 3.59
(t, 2H), 3.61-4.02 (m, 4H), 4.09 (m, 2H), 4.55 (s, 2H), 5.24 (m,
1H), 5.86 (m, 2H), 6.73 (s, 1H), 6.86 (d, 1H), 7.03 (d, 2H), 7.15
(d, 1H), 7.50 (d, 2H), 7.72 (s, 4H). 13C NMR: δ ) 13.9, 26.7,
27.2, 27.9, 29.7, 32.2, 40.4, 42.8, 43.0, 43.7, 46.5, 55.9, 61.0,
74.9, 76.7, 95.4, 112.6, 114.0, 115.5, 127.0, 128.1, 128.9, 129.3,
133.1, 155.3, 156.3, 156.8, 169.4, 171.4, 186.1. Anal. Calcd
(C32H41ClN4O5) C, H, Cl, N.
(2-Ca r b a m im id oyl-1,2,3,4-t et r a h yd r o-isoq u in olin -7-
yloxy){4-[1-(5,5-d im et h yl-3-oxocycloh ex-1-en yl)p yr r oli-
d in -3(S)-yloxy]p h en yl}a cetic Acid Hyd r och lor id e (36).
Prepared from 35 using the procedure described for 17: pale
yellow solid; yield 42%; mp 175-178 °C. (+)-FAB-MS: 533
(MH+). 1H NMR: δ ) 1.07 (s, 6H), 2.26 (m, 2H), 2.30-2.75
(m, 4H), 2.82 (t, 2H), 3.60 (t, 2H), 3.65-4.25 (m, 4H), 4.57 (s,
2H), 5.22 (m, 1H), 5.74 (m, 2H), 6.74 (s, 1H), 6.86 (d, 1H), 7.02
(d, 2H), 7.15 (d, 1H), 7.51 (d, 2H), 7.67 (s, 4H). 13C NMR: δ )
26.7, 27.2, 27.9, 29.7, 32.2, 40.4, 43.0, 43.1, 46.4, 48.8, 56.0,
74.8, 76.6, 95.5, 112.4, 114.0, 115.4, 126.8, 128.7, 128.9, 129.2,
133.0, 155.5; 156.2, 156.6, 170.6, 170.8, 186.3. Anal. Calcd
(C30H37ClN4O5) C, H, Cl, N.
Ack n ow led gm en t. We are grateful to Dr. H. Hin-
dermayr, Dr. U. Anders, and S. Laukenmann for mass
and NMR spectroscopic determinations. We also thank
S. Braun for combustion analyses, B. Gebhardt for
kinetic measurements, W. Neuert for aPTT and TT
determinations, and Dr. J . Rewinkel, Dr. A. Adang, and
Dr. S. van Aelst, NV Organon, Oss (The Netherlands),
for helpful discussions.
En zym e Kin etics. Inhibition constants were, determined
by means of chromogenic assays as previously described.8 For
results, see Table 1.
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solution (100 µL STA Calcium Chloride; Diagnostica Stago/
Boehringer Mannheim GmbH, Germany). The addition of this
reagent started a stop watch, which stopped when the plasma
had coagulated. Quadruplicate determinations were per-
formed for each individual assay. The aPTT was 28-35 s in
the control experiments; samples containing a test compound
exhibited prolonged clotting times. The aPTT increase (i.e.,
the difference to the control experiment) in seconds was
determined at concentrations of the test compound in the
citrated plasma of 1000, 200, 100, 10, and 1 µM. ED200 values
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the Factor Xa Inhibitor DX-9065a Using Palladium-Catalyzed
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(18) Kunz, H.; Unverzagt, C. Der Allyloxycarbonyl(Aloc)-Rest - die
Verwandlung einer untauglichen in eine wertvolle Amino-
schutzgruppe fu¨r die Peptidsynthese. Angew. Chem. 1984, 96,
426-427.
(19) The application of pyrrolidine as an allyl scavenger in the
palladium-catalyzed cleavage of allyl carbamates has been
reported recently: (a) Howard, P. W.; Thurston, D. E. The Use
of Carbamate Protecting Groups in the Synthesis of Monomeric
and Dimeric Pyrrolo[2,1-c]benzodiazepines. J . Pharm. Pharma-
col. 1995, 1078. (b) See also: Roos, E. C.; Bernabe´, P.; Hiemstra,
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tion of Amides and Dipeptides. J . Org. Chem. 1995, 60, 1733-
1740.
(20) The enamine derivative of 20 has not been detected under these
conditions, not even in traces. This is attributed to the generally
enhanced tendency of pyrrolidines to form enamines.
(21) Dangles, O.; Guibe´, F.; Balavoine, G.; Lavielle, S.; Marquet, A.
Selective Cleavage of the Allyl and Allyloxycarbonyl Groups
through Palladium-Catalyzed Hydrostannolysis with Tributyltin
Hydride: Application to the Selective Protection-Deprotection
of Amino Acid Derivatives and in Peptide Synthesis. J . Org.
Chem. 1987, 52, 4984-4993.
(22) Concerning the nomenclature of the subsites of fXa, see ref 14.
(23) Hilpert, K.; Ackermann, J .; Banner, D. W.; Gast, A.; Gubernator,
K.; Hadva´ry, P.; Labler, L.; Mu¨ller, K.; Schmid, G.; Tschopp, T.
B.; van de Waterbeemd, H. Design and Synthesis of Potent and
Highly Selective Thrombin Inhibitors. J . Med. Chem. 1994, 37,
3889-3901.
(24) For the MD all residues of the S1 pocket were allowed to move
freely. All other residues were kept fixed. Solvents have not been
used. Trajectories were not written out, but the movement of
the residues was followed on the screen. For docking experiments
the inhibitors were manually adjusted and minimized to con-
vergence using the CVFF force field of the Insight II/Discover
(MSI, San Diego, CA) program package. The protein atoms were
fixed for this purpose, and a constraint was given from the
exocyclic amino nitrogen atoms to Asp189 in the S1 pocket.
(25) Stubbs, M. T.; Huber, R.; Bode, W. Crystal Structures of Factor
Xa Specific Inhibitors in Complex with Trypsin: Structural
Grounds for Inhibition of Factor Xa and Selectivity Against
Thrombin. FEBS Lett. 1995, 375, 103-107.
(26) Inhibition constants of the ethyl ester of DX-9065a (unpublished
results): Ki ) 0.040 µM, Ki
plasmin
) 16 µM, Ki
) 0.28 µM,
fXa
thrombin
trypsin
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