Design, synthesis and biological activity of YM-60828 derivatives: Potent and orally-bioavailable factor Xa inhibitors based on naphthoanilide and naphthalensulfonanilide templates

Article abstract of DOI:10.1016/S0968-0896(02)00106-2

Factor Xa (FXa) is a serine protease which plays a pivotal role in the coagulation cascade. The inhibition of FXa has received great interest as a potential target for the development of new antithrombotic drug. Herein we describe a series of novel 7-amidino-2-naphthoanilide and 7-amidino-2-naphthalensulfonanilide derivatives which are potent FXa inhibitors. These scaffolds are rigid and are allowed to adopt an L-shape conformation which was estimated as the active conformation based on a docking study of YM-60828 with FXa. Optimization of the side chain at the central aniline nitrogen of 7-amidino-2-naphthoanilide has led to several potent and orally active FXa inhibitors. 5h (YM-169964), the best compound of these series, showed potent FXa inhibitory activity (IC₅₀=3.9 nM) and effectively prolonged prothrombin time by 9.6-fold ex vivo at an oral dose of 3 mg/kg in squirrel monkeys.

Full text of DOI:10.1016/S0968-0896(02)00106-2

Bioorganic & Medicinal Chemistry 10 (2002) 2597–2610
Design, Synthesis and Biological Activity of YM-60828
Derivatives: Potent and Orally-Bioavailable Factor Xa Inhibitors
Based on Naphthoanilide and Naphthalensulfonanilide Templates
Fukushi Hirayama,a,* Hiroyuki Koshio,a Tsukasa Ishihara,a Susumu Watanuki,a
Shunichiro Hachiya,a Hiroyuki Kaizawa,a Takahiro Kuramochi,a Naoko Katayama,a
Hiroyuki Kurihara,a Yuta Taniuchi,b Kazuo Sato,c Yumiko Sakai-Moritani,a Seiji Kaku,a
a
Tomihisa Kawasaki,a Yuzo Matsumoto,a Shuichi Sakamotoa andShin-ichi Tsukamoto
aInstitute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan
bClinical Development Department, Yamanouchi Pharmaceutical Co., Ltd., 3-17-1 Hasune, Itabashi, Tokyo 174-8612, Japan
cProject Coordination Department, Yamanouchi Pharmaceutical Co., Ltd., 3-17-1 Hasune, Itabashi, Tokyo 174-8612, Japan
Received31 January 2002; accepted16 March 2002
Abstract—Factor Xa (FXa) is a serine protease which plays a pivotal role in the coagulation cascade. The inhibition of FXa has
received great interest as a potential target for the development of new antithrombotic drug. Herein we describe a series of novel
7-amidino-2-naphthoanilide and 7-amidino-2-naphthalensulfonanilide derivatives which are potent FXa inhibitors. These scaffolds
are rigidandare allowedto adopt an L-shape conformation which was estimatedas the active conformation basedon a docking
study of YM-60828 with FXa. Optimization of the side chain at the central aniline nitrogen of 7-amidino-2-naphthoanilide has led
to several potent andorally active FXa inhibitors. 5h (YM-169964), the best compoundof these series, showedpotent FXa inhi-
bitory activity (IC50=3.9 nM) andeffectively prolongedprothrombin time by 9.6-foldex vivo at an oral dose of 3 mg/kg in squirrel
monkeys. # 2002 Elsevier Science Ltd. All rights reserved.
Introduction
Factor Xa (FXa) is a trypsin-like serine protease that
links the intrinsic andextrinsic coagulation cascade. The
primary role of FXa is the proteolytic activation of
prothrombin to generate thrombin after forming a pro-
thrombinase complex composedof FXa, factor Va, and
calcium on the phospholipidmembrane. Bloodclotting
occurs through conversion of fibrinogen to insoluble
fibrin andactivating platelets by the generatedthrom-
bin. Although thrombin inhibitors have been exten-
sively studied as an anticoagulant,2 only argatroban3
has been marketedas a parenteral drug andnone of the
oral thrombin inhibitors has been launchedyet. More
recently numerous efforts have been made to discover
FXa inhibitors.4 A FXa inhibitor efficiently interrupts
both the intrinsic andextrinsic activation cascaed.
Moreover, since it affects coagulation specifically but
not platelet function in contrast to a thrombin inhibitor,
these mechanisms shouldhave a reudcedeffect on
abnormal bleeding. Actually, FXa inhibitors have
shown goodantithrombotic efficacy in animal models of
thrombosis.5À8 Further, in direct comparisons between
Factor Xa inhibitors andthrombin inhibitors, the for-
mer were shown to be superior antithrombotic agents.6,7
Intravascular clot formation is an essential factor in a
number of cardiovascular diseases such as myocardial
infarction, unstable angina, deep vein thrombosis, pul-
monary embolism, andischemic stroke. The interrup-
tion of the coagulation cascade is one of the most
important strategies for inhibition of clot formation
which is, in turn, for prevention andtreatment of these
thrombotic disorders. Warfarin, an inhibitor of the
biosynthesis of the vitamin K-dependent coagulation
factor, is currently the only marketedoral anticoagulant
agent. However due to its mode of action, warfarin has
many clinical problems such as slow onset of action,
adverse effect on bleeding and interaction with many
drugs and foods; hence, it requires individual dose
1
titration andperiodic monitoring. Therefore, there is a
serious needto develop orally active anticoagulants that
are clinically safe andwhich require less monitoring.
*Corresponding author. Tel.: +81-298-54-1563; fax: +81-298-52-
2971; e-mail: hirayaf@yamanouchi.co.jp
0968-0896/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S0968-0896(02)00106-2

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F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
At present, FXa inhibitors are regarded as potentially
ideal anticoagulants.
under acidic conditions (HCl/H2O) gave carboxyl deri-
vatives 5g–5j in goodyield.
In our laboratory, we have also made a continuous
study of FXa inhibitors and have reported a potent and
orally bioavailable FXa inhibitor YM-60828.9,10 Fur-
thermore, the utility of a FXa inhibitor was confirmed
The preparative route to naphthalensulfonanilide deri-
vatives 5k and 5l is shown in Scheme 2. Curtius rear-
rangement of 7-cyanonaphthalene-2-carboxylic acid( 2)
in tert-butyl alcohol gave N-(tert-butoxycarbonyl)amino
naphthalene derivative 6. Deprotection of the BOC
group in 6 under acidic conditions, subsequent diazoti-
zation with sodium nitrite in concentrated hydrochloric
acidgeneratedthe diazonium salt, which was then trea-
ted with sulfur dioxide and cuprous chloride to give 7-
cyanonaphthalen-2-sulfonyl chloride. Condensation of
aniline 1 with the sulfonyl chloride afforded naphtha-
lensulfonanilide intermediate 4g. Subsequent conversion
of 4g to bis-amidine 5k was accomplishedby the same
conditions described above. N-Ethyl analogue 5l was
preparedfrom 5k with ethanol under Mitsunobu con-
densation conditions (PPh3, DEAD, THF).
in a number of thrombosis animal models using YM-
7,8
60828 andits mesylate salt YM-75466.
In this paper,
we describe the results of our work on the synthesis and
SAR of YM-60828 derivatives containing carboxamide
andsulfonamide linkers.
Chemistry
The synthesis of naphthoanilide derivatives 5a–5j is
shown in Scheme 1. Key naphthoanilide intermediate 4a
was obtainedfrom conednsation of aniline
110 and
7-cyanonaphthalene-2-carboxylic acid( 2), which was
preparedby oxidation of 7-formylnaphthalene-2-carbo-
nitrile.10 Alkylation of 4a with various alkyl halides
Phenethylsulfonanilide derivative 5m was also synthe-
sizedas shown in Scheme 3 via similar route as naph-
thalensulfonanilide derivative 5k. Known phenyl
acetaldehyde 711 was reduced by using NaBH4 to phe-
nethyl alchol, which was treatedwith thionyl chloride to
affordphenethyl chloride 8. It was then reactedwith
sodium sulfite in water at reflux, followed by treatment
with thionyl chloride to provide phenethylsulfonyl
chloride. Phenethylsulfonanilide intermediate 9 was
obtained by condensation of the sulfonyl chloride and
aniline 1 followedby deprotection of the BOC group.
Intermediate 9 was carriedon following the same
methods described above to give bis-amidine 5m.
gave N-substitutednaphthoanilieds
4b, 4c, 4e and 4f.
Because the condensation of 4a andethyl 3-chloro-
propionate or ethyl acrylate was not successful, another
preparative route to 4d was employed. Aniline 1 was
first coupledwith ethyl acrylate to afford N-substituted
aniline 3 in rather low yieldandthe nitrogen of piper-
idine was reprotected by di-tert-butyl dicarbonate. This
was then condensed with 7-cyanonaphthalene-2-carbonyl
chloride to give 4d. Treatment of the intermediates 4a–
4f under Pinner conditions (HCl/MeOH or EtOH)
afforded the imidates which were immediately reacted
with excess ammonium acetate to give the correspond-
ing mono-amidine derivatives. The tert-butoxycarbonyl
(BOC) protecting group was simultaneously depro-
tected to yield a secondary amine under these conditions
and then these mono-amidine derivatives were con-
vertedto bis-amidines 5a–5f by the reaction with ethyl
acetimidate and triethylamine. Hydrolysis of 5c–5f
Styrensulfonanilide derivatives 5n and 5o were prepared
via another methodology outlined in Scheme 4. Aniline
1 was treatedwith 2-chloro-1-ethanesulfonyl chloride to
give unstable vinylsulfonanilide 10, which was immedi-
ately reacted with 3-bromobenzonitrile under standard
Heck reaction by heating (140 ꢀC) with palladium(II)
Scheme 1. Synthesis of naphthoanilide derivatives: (a) 7-cyanonaphthalene-2-carboxylic acid (2), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide
hydrochloride, 1-hydroxybenzotriazole, Et3N, DMF; (b) ethyl acrylate, AcOH; (c) di-tert-butyl dicarbonate, CHCl3; (d) EtI for 4b, RBr for 4c, 4e,
4f, NaH, DMF; (e) 2, SOCl2, then 3, pyridine, 4-dimethylaminopyridine, CH2Cl2; (f) HCl, EtOH or MeOH; (g) NH4OAc, EtOH or MeOH; (h) ethyl
acetimidate hydrochloride, Et3N, EtOH or MeOH; (i) HCl, H2O.

F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
2599
Scheme 2. Synthesis of naphthalensulfonanilide derivatives: (a) diphenylphosphoryl azide, tert-butanol, Et3N; (b) HCl, 1,4-dioxane, EtOAc; (c)
NaNO2, HCl, AcOH, H2O, then SO2, CuCl; (d) 1, pyridine, 1,2-dichloroethane; (e) HCl, EtOH; (f) NH4OAc, EtOH; (g) ethyl acetimidate hydro-
chloride, Et3N, EtOH; (h) EtOH, PPh3, DEAD, THF.
Scheme 3. Synthesis of phenethylsulfonanilide derivative: (a) NaBH4, EtOH (b) SOCl2, CH2Cl2; (c) Na2SO3, H2O; (d) SOCl2, benzene; (e) 1, pyri-
dine, 1,2-dichloroethane; (f) 4 N HCl/EtOAc; (g) HCl, EtOH; (h) NH4OAc, EtOH; (i) ethyl acetimidate hydrochloride, Et3N, EtOH.
Scheme 4. Synthesis of styrylsulfonanilide derivatives: (a) 2-chloro-1-ethanesulfonyl chloride, pyridine, DMAP, CH2Cl2; (b) PPh3, Pd(OAc)2, DMF
then 3-bromobenzonitrile, 10, Et3N; (c) MeI, DMF, K2CO3; (d) HCl, EtOH; (e) NH4OAc, EtOH; (f) ethyl acetimidate hydrochloride, Et3N, EtOH.
acetate, triphenylphosphine andtriethylamine in DMF
to yield styrensulfonanilide intermediate 4h. This was
readily N-alkylatedby methyl ioided andpotassium
carbonate to give N-methylstyrensulfonanilide 4i. Bis-
amidine derivatives 5n, 5o were obtainedfrom 4h and
4i, respectively, by the same manner described above.
the carbonyl oxygen of Ile-227. Second, the piperidine
group sits in the aryl-binding pocket defined by the
three aromatic amino acids Phe-174, Tyr-99 and Trp-
215. Third, the acetimidoyl group forms a water-medi-
atedhydrogen bondto the carbonyl oxygen atoms of
Thr-98 andIle-175. On the other hand, little binding
contribution was observedfor the side chain sulfonyla-
cetic acidmoiety which is near the solvent accessible
surface at the outer ridge of the active site and is weakly
hydrogen bonded to Gln-192. We designed to shift the
side chain carboxamide or sulfonamide bond in the ser-
ies of YM-60828 derivatives10 to the central anilino-
methylnaphthalene linkage (Fig. 2). These transformations
afforded naphthoanilide and naphthalensulfonanilide
templates as the rigidscaffoldthat wouldbe able to
adopt the L-shape conformation predominantly. Then
the structural modification of these two templates was
performedto discover some novel, potent andorally
bioavailable FXa inhibitors.
Results and Discussion
At the initiation of this program, the docking study of
YM-60828 andFXa was performedbasedon the X-ray
crystal structure of it complexedto a relatedenzyme,
trypsin (Fig. 1). This study revealed that YM-60828
takes an L-shape conformation by binding to the FXa
active site with three key interactions. First, the naph-
thamidine moiety is in the S1 specificity pocket and
forms a hydrogen bond network to Asp-189 and Gly-
218. There is also a water-mediated hydrogen bond to

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F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
Figure 1. Binding model of YM-60828 to factor Xa.
Table 1. Effect of the ethyl substituent in carboxamide, sulfonamide
andaminomethylene derivatives
CompdR
X
IC
50 (nM)a
Factor Xa
Thrombin
Trypsin
5a
5b
5k
5l
5r
5s
H
Et
H
Et
H
CO
CO
SO2
SO2
CH2
CH2
2242.5
9.1
11.7
181.1
19.5b
25.1
>100,000
>100,000
>100,000
>100,000
>100,000
>100,000
26,390
210
230
5248
278b
235
Figure 2.
Table 1 shows evaluations of the templates which con-
tain three types of linkers such as carboxamide (5a and
5b), sulfonamide (5k and 5l) andaminomethylene ( 5r10
and 5s). It was noteworthy that the effects of the N-ethyl
substituent (R) on central aniline nitrogen were quite
different depending on the structure of its linkers. In the
naphthylmethylaniline derivatives 5r and 5s, FXa inhi-
bitory activities were not greatly affectedby existence of
the ethyl substituent. This result was considered to be
reasonable because the modeling experiments of YM-
60828 boundwith FXa (Fig. 1) suggestedthat the N-
alkyl moiety was directed to the solution and made little
contact with the enzyme. On the other hand, the ethyl
substituent strongly influencedthe FXa inhibitory
activities of the naphthoanilide and naphthalensulfona-
nilide derivatives. Unsubstituted naphthoanilide deriva-
tive 5a showeda markeddecrease in FXa inhibitory
activity comparedto that of the ethyl substitutedana-
logue 5b. In contrast, unsubstitutednaphthalensulfona-
nilide derivative 5k posessedmore potent FXa
inhibitory activity than that of the ethyl substituted
analogue 5l. Based on the modeling study of YM-60828
boundwith FXa (Fig. 1), naphthalene andbenzene ring
orientedwith syn geometry in the active site (L-form).
On the other hand, it has been known that N-methyl-
benzanilide exists in the cis-amide conformation while
unsubstitutedbenzanilide exists in the trans-amide con-
Et
aHuman purifiedenzymes were used. IC 50 values represent the average
of three determinations with the average standard error of the mean
<20%.
bDeterminedby duplicated( n=1).
12
formation in both crystal andsolvent.
From these
findings, it was considered that N-ethylnaphthoanilide
5b existedpredominantly in the cis-amide conformation
that resultedin its taking the active conformation. But
the unsubstitutedanalogue 5a was almost lockedinto
the inactive trans-amide conformation. The quite differ-
ent potencies observedbetween 5a and 5b were prob-
ably due to switching between these two different
conformations. This discussion was supported by the
NMR study of 5a and 5b in D2O, in which NOE was
observedbetween protons on naphthalene andbenzene
in 5b, but was not observedin 5a (Fig. 3). Similarly,
unsubstitutednaphthalensulfonanilied
5k couldexist
predominantly in the active cis conformation andthe
ethyl-substitutedanalogue 5l took another inactive
trans conformation in contrast to carboxamide deriva-
tives 5a and 5b. Actually, X-ray crystallographic analy-
sis of some benzensulfonanilide derivatives has reported
them to exsist as not in a planar conformation.13

F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
2601
Potent FXa inhibitors 5b and 5k showedhigh selectivity
retainedthe in vitro FXa inhibitory activity and
(>5000-fold) over thrombin while the selectivity over
trypsin was moderate (ca. 20-fold). These two com-
pounds were identified as novel leads for optimization.
The data in Table 2 summarize the derivatives of naph-
thalensulfonanilide 5k. In addition to the IC50 values,
CT2 values of the human plasma prothrombin time (PT)
were also tabulated. The CT2 value is defined as the
concentration requiredto double clotting time. More-
over oral efficacy was also evaluatedby prolongation of
PT ex vivo after oral administration in mice. Although
the potency observedwith 5k in vitro IC50 of FXa was
well translatedinto potent activity in vitro PT assays, ex
vivo activity following oral dosing was poor. Replace-
ment of the naphthalene in 5k with a styrene (5n)
increasedthe selectivity against trypsin (72-fold), but
phenethyl derivative 5m decreased the FXa inhibitory
activity. Following the same trendas for the naphtha-
lensulfonanilide derivatives, the N-alkylation of styr-
ensulfonanilide (5o) causeda decrease in the activity.
Regioisomers of 5n were also evaluatedandthe para-
substituted amidinostyryl derivative 5p showedpoor
FXa inhibitory activity, in contrast, the meta-sub-
stitutedcentral benzene derivative 5q hadcomparable
FXa inhibitory activity andselectivity over trypsin
comparedwith that of 5n. Although these two styr-
ensulfonanilide derivatives 5n and 5q showedpotent
andselective FXa inhibitory activities andalso have
potent PT CT2 values, the efficacies after oral adminis-
Figure 3.
Table 2. SAR of sulfonamide derivatives
CompdR
IC
50 (nM)a
Thrombin
>100,000
CT2 (mM)b PTc
PT/control PTd mice
Factor Xa
11.7
Trypsin
230
5k
5m
5n
5o
5p
5q
0.23
0.49
0.23
NTe
NTe
0.20
0.21f
1.2
1.2
48.7
12.0
>100,000
>100,000
>100,000
>100,000
>100,000
>100,000
1496
865
1.7
137.3
1764.1
19.6
5421
17,508
1861
216
NTe
NTe
1.3
YM-60828
2.3
2.6
aRefer to Table 1.
bValues represent the concentration required to double clotting time and represent the average of four determinations with the average standard
error of the mean <20%.
cProthrombin time using human plasma.
dThe relative prothrombin time comparedwith that measuredusing normal mice plasma at 0.5 h after oral administration (100 mg/kg, n=3).
eNot tested.
fn=3.

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F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
tration were not good. Among them 5n demonstrated
modest oral efficacy ex vivo (prolong PT by 1.7-fold).
Replacement of naphthalene in 5g with benzofuran (5t)
causeda large decrease in potency andreplacement with
styrene (5u) was also not well toleratedin contrast to the
sulfonamide derivative (5k vs 5n). Extension of the
acetic acidmoiety in 5g with methylene (5h and 5i) and
phenylene (5j) maintainedthe inhibitory activity against
FXa. These SAR may indicate that there is a wide space
in this area and naphthoanilide derivatives have the
same binding conformation as that of YM-60828. All
strong FXa inhibitory potencies of this series of com-
pounds were well translated into submicromolar anti-
coagulant activities in vitro PT assay (CT2). The
potencies were the same or slightly less than that of
YM-60828. The efficacy after oral administration of
these compounds was evaluated by prolongation of PT
ex vivo in mice andsquirrel monkeys. In mice, all com-
pounds (5g–5j) showedquite potent activity, which
prolongedPT more than 2-foldboth at 0.5 h and2.0 h.
In contrast, there was wide variation in efficacy of the
test in squirrel monkeys (Fig. 4). Compounds 5g and 5i
hadsame or slightly higher efficacy than that of YM-
75466 (methanesulfonate salt of YM-60828), but the
phenylene insertion compound 5j showedpoor efficacy.
The results of SAR studies for the derivatives of 5b are
shown in Table 3. Unfortunately, ex vivo evaluation of
5b after oral administration in mice failed because six of
the 12 mice were dead within 10 min after dosing at
100 mg/kg. This acute lethal toxicity, probably caused
by hypotension, has been known as a side effect for
strong basic amidine and guanidine compounds such as
a thrombin inhibitor14 andthrombin receptor antago-
nist.15 To reduce the basicity of the compound, the ethyl
moiety (R) in 5b was replacedwith the acetic acidmoi-
ety. The resulting compound 5g slightly increase the
inhibitory activity for FXa andreduce the toxicity, with
none of the lethal adverse reaction after oral adminis-
tration (100 mg/kg) in mice. Furthermore, the previous
study on YM-60828 demonstrated that the compounds
which contain a carboxyl group hada tendency to have
potent ex vivo activity after oral administration in
mice.10 Because of these two desirable effects of a car-
boxyl group, derivatives bearing the carboxyl moiety
were synthesizedandevaluated.
Table 3. SAR of carboxamide derivatives
CompdR
IC
50 (nM)a
Thrombin
>100,000
CT2 (mM)b PTc
PT/control PTd
Factor Xa
9.1
Trypsin
210
0.5 h
2.0 h
NDg
5b
5g
5h
5i
0.35
NDg
3.7
4.2
3.9
>100,000
>100,000
>100,000
>100,000
>100,000
>100,000
>100,000
391
291
0.22
2.7
2.5
0.29
3.1
3.5
314
0.27
2.9
2.6
5j
2.7
194
0.26
3.2
2.6
5t
5u
1626.8
101.6
2.3
48,144
9099
216
NTe
NTe
NTe
2.6
NTe
NTe
1.7
NTe
YM-60828
0.21f
aRefer to Table 1.
bValues represent the concentration required to double clotting time and represent the average of four determinations with the average standard
error of the mean <20%.
cProthrombin time using human plasma.
dThe relative prothrombin time comparedwith that measuredusing normal mice plasma at 0.5 h and2 h after oral administration in mice (100 mg/
kg, n=3).
eNot tested.
fn=3.
gNot determined.

F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
2603
(10.00 g, 55.2 mmol) in acetonitrile (250 mL) andH O
2
(250 mL) at ambient temperature was added sodium
chlorite (purity 80%, 31.20 g, 276 mmol). After stirring
under reflux for 20 h, the reaction mixture was allowed
to reach ambient temperature and0.7 N aqueous NaOH
(700 mL) was added. The mixture was washed with
ethyl acetate andthe aqueous solution was acidified
with 12 N HCl. The resulting precipitate was filtered,
washedwith H O anddriedin vacuo to give 2 (10.08 g,
2
92%) as a white solid: mp 276–278 ꢀC; 1H NMR
(DMSO-d6) d 7.91 (1H, dd, J=1.5, 8.3 Hz), 8.10–8.22
(3H, m), 8.72 (1H, s), 8.79 (1H, s); FAB MS m/e
(MÀ1)À 196.
Ethyl 3-{4-[(1-tert-butoxycarbonyl-4-piperidyl)oxy]anili-
no}propionate (3). A solution of tert-butyl 4-(4-amino-
phenoxy)piperidine-1-carboxylate (1) (4.07g, 13.9 mmol)10
andethyl acrylate (1.39 g,ꢀ 13.9 mmol) in acetic acid
(28 mL) was stirredat 100 C for 12 h. After the reaction
mixture was concentratedin vacuo, to the resulting
residue was added CHCl3, which was washedwith 10%
aqueous K2CO3, dried over Na2SO4 andconcentrated
Figure 4. Anticoagulant activity of selectedcarboxamide derivatives
andYM-75466 (methanesulfonate salt of YM-60828) after oral
administration at 3 mg/kg in squirrel monkeys. The relative pro-
thrombin time comparedwith that measuredusing normal plasma
were determined in blood samples taken at the indicated time points
after administration (ÆSEM, n=3).
Among them, the best compoundwas 5h (YM-169964),
which remarkably prolongedPT by 9.6-foldat 1.0 h. 5h
was further evaluatedin pharmacokinetic study follow-
ing oral administration in dogs (10 mg/kg, n=3). It
demonstrated good profiles with Cmax (2429 ng/mL),
AUC (10246 ng h/mL) and Tmax (0.8 h).
in vacuo. To a stirredsolution of the residue in CHCl
3
(28 mL) at ambient temperature was added di-tert-butyl
dicarbonate (1.53 g, 7.0 mmol). After the reaction mix-
ture was concentratedin vacuo, the resulting residue
was chromatographedon silica gel eluting with ethyl
acetate (EtOAc)/n-hexane(Hex) (17:83) to give
3
1
(700 mg, 13%) as a pale brown viscous oil: H NMR
(CDCl3) d 1.23 (3H, t, J=6.9 Hz), 1.43 (9H, s), 1.61–
1.71 (2H, m), 1.79–1.89 (2H, m), 2.56 (2H, t, J=6.3 Hz),
3.19–3.28 (2H, m), 3.36 (2H, t, J=6.3 Hz), 3.63–3.72
(2H, m), 4.12 (2H, q, J=6.9 Hz), 4.18–4.26 (1H, m),
6.54 (2H, d, J=4.0 Hz), 6.76 (2H, d, J=9.0 Hz); FAB
MS m/e (M+1)+ 393.
Conclusion
We have designed and synthesized a series of naph-
thoanilide and naphthalensulfonanilide series of com-
pounds as FXa inhibitors. Among these compounds,
naphthoanilide derivatives (5g–j) showedlow nanomo-
lar potency in FXa inhibitory activities, andpotent ex
vivo activities after oral administration in mice. The
best compoundwas 5h (YM-169964) which hadexcel-
lent ex vivo activity following oral dosing in mice and
squirrel monkeys andgoodpharmacokinetic profiles in
dogs. Subsequent communications from our labora-
tories will describe further results of the investigation of
relatedscaffolds.
N-{4-[(1-tert-Butoxycarbonyl-4-piperidyl)oxy]phenyl}-7-
cyano-2-naphthamide (4a). To a stirredsolution of 7-
cyanonaphthalene-2-carboxylic acid( 2) (1.5g, 7.6 mmol)
and tert-butyl 4-(4-aminophenoxy)piperidine-1-carboxy-
late (1) (2.2 g, 7.6 mmol) in N,N-dimethylformamide
(DMF) (30 mL) at ambient temperature was added
1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydro-
chloride (1.75 g, 9.1 mmol), 1-hydroxybenzotriazole
(1.03 g, 9.1 mmol) andtriethylamine (Et 3N) (1.26 mL,
9.1 mmol). After stirring at ambient temperature for
24 h, the reaction mixture was filteredandconcentrated
in vacuo. The resulting residue was crystallized from
ethanol (EtOH) to give 4a (2.78 g, 78%) as a white solid:
Experimental
Chemistry
mp 199–201 ꢀC; H NMR (CDCl3) d 1.48 (9H, s), 1.70–
1
1H NMR spectra were measuredwith a JEOL EX90,
EX400 or GX500 spectrometer; chemical shifts are
expressedin d units using tetramethylsilane as the stan-
dard (in NMR description, s=singlet, d=doublet, t=
triplet, q=quartet, m=multiplet, andbr=broadpeak).
Mass spectra were recorded with a Hitachi M-80 or
JEOL JMS-DX300 spectrometer. Melting points were
measuredwith a Yanaco MP-500D melting point appa-
ratus without correction. ODS column chromatography
was performedon YMC gel (ODS-A 120–230/70).
1.80 (2H, m), 1.85–1.98 (2H, m), 3.28–3.40 (2H, m),
3.65–3.70 (2H, m), 4.41–4.50 (1H, m), 6.94 (2H, d,
J=8.8 Hz), 7.59 (2H, d, J=8.8 Hz), 7.71 (1H, d,
J=9.0 Hz), 7.94–8.03 (2H, m), 8.06–8.15 (2H, m), 8.29
(1H, s), 8.41 (1H, s); FAB MS m/e (M)+ 471.
N-{4-[(1-tert-Butoxycarbonyl-4-piperidyl)oxy]phenyl}-7-
cyano-N-ethyl-2-naphthamide (4b). To a stirredsolution
of 4a (707 mg, 1.5 mmol) in DMF (10 mL) at ambient
temperature was added 60% NaH in paraffin liquid
(120 mg, 3.0 mmol). After 20 min ethyl iodide (0.36 mL,
4.5 mmol) was added to the reaction mixture and
stirredfor 1 h at ambient temperature. The reaction was
7-Cyanonaphthalene-2-carboxylic acid (2). To a stirred
suspension of 7-formylnaphthalene-2-carbonitrile10

2604
F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
quenchedby the addition of aqueous NH 4Cl andcon-
centrated in vacuo. To the resulting residue was added
H2O followedby extracting with CHCl . The organic
J=7.5 Hz), 3.21–3.33 (2H, m), 3.58–3.71 (2H, m), 3.97
(2H, t, J=7.2 Hz), 4.13 (2H, q, J=7.2 Hz), 4.29–4.37
(1H, m), 6.72 (2H, d, J=8.6 Hz), 6.98 (2H, d,
J=8.6 Hz), 7.47 (1H, d, J=8.4 Hz), 7.59 (1H, dd,
J=1.8, 8.4 Hz), 7.65 (1H, d, J=9.0 Hz), 7.81 (1H, d,
J=8.4 Hz), 7.88 (1H, s), 8.01 (1H, s); FAB MS m/e
(M)+ 585.
3
extracts were dried over Na2SO4 andconcentratedin
vacuo. The resulting residue was chromatographed on
silica gel eluting with EtOAc/Hex (30:70) to give 4b
(663 mg, 89%) as a white amorphous powder: 1H NMR
(CDCl3) d 1.26 (3H, t, J=6.8 Hz), 1.45 (9H, s), 1.59–
1.73 (2H, m), 1.78–1.89 (2H, m), 3.21–3.31 (2H, m),
3.60–3.70 (2H, m), 3.99 (2H, q, J=6.8 Hz), 4.29–4.37
(1H, m), 6.73 (2H, d, J=8.8 Hz), 6.97 (2H, d,
J=8.8 Hz), 7.49 (1H, d, J=8.3 Hz), 7.59 (1H, dd,
J=1.4, 8.3 Hz), 7.65 (1H, d, J=8.3 Hz), 7.81 (1H, d,
J=8.3 Hz), 7.89 (1H, s), 8.09 (1H, s); FAB MS m/e
(M+1)+ 500.
Methyl 4-[(N-{4-[(1-tert-butoxycarbonyl-4-piperidyl)oxy]
phenyl}-N-(7-cyano-2-naphthoyl)amino)methyl]benzoate
(4f). Compound 4f was synthesizedfrom 4a andmethyl
4-(bromomethyl)benzoate according to the same proce-
dure as that for 4b. Compound 4e was obtainedas a
white amorphous powder (95% yield): 1H NMR
(CDCl3) d 1.45 (9H, s), 1.55–1.68 (2H, m), 1.77–1.86
(2H, m), 3.19–3.31 (2H, m), 3.58–3.71 (2H, m), 3.89
(3H, s), 4.25–4.35 (1H, m), 5.19 (2H, s), 6.66 (2H, d,
J=8.7 Hz), 6.85 (2H, d, J=8.7 Hz), 7.43 (2H, d,
J=8.7 Hz) 7.53 (1H, d, J=8.4 Hz), 7.57 (1H, dd,
J=1.5, 8.4 Hz), 7.66 (1H, d, J=8.4 Hz), 7.80 (1H, d,
J=8.4 Hz), 7.94 (1H, s), 8.00 (2H, d, J=8.7 Hz), 8.08
(1H, s); FAB MS m/e (M)+ 620.
Ethyl N-{4-[(1-tert-butoxycarbonyl-4-piperidyl)oxy]phe-
nyl}-N-(7-cyano-2-naphthoyl)glycinate (4c). Compound
4c was synthesizedfrom 4a andethyl bromoacetate
according to the same procedure as that for 4b. Com-
pound 4c was obtainedas a white amorphous powder
(98% yield): 1H NMR (CDCl3) d 1.32 (3H, t,
J=6.9 Hz), 1.45 (9H, s), 1.57–1.72 (2H, m), 1.76–1.89
(2H, m), 3.20–3.32 (2H, m), 3.57–3.71 (2H, m), 4.26
(2H, q, J=6.9 Hz), 4.28–4.38 (1H, m), 4.60 (2H, s), 6.72
(2H, d, J=9.0 Hz), 7.10 (2H, d, J=9.0 Hz), 7.53 (1H, d,
J=8.4 Hz), 7.60 (1H, dd, J=1.5, 8.4 Hz), 7.67 (1H, d,
J=8.7 Hz), 7.82 (1H, d, J=8.4 Hz), 7.95 (1H, s), 8.10
(1H, s); FAB MS m/e (M+1)+ 558.
General procedure for conversion to bis-amidine deriv-
atives. N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-7-
amidino-N-ethyl-2-naphthamide (5b). HCl gas was bub-
bledthrough a solution of 4b (606 mg, 1.2 mmol) in
EtOH (10 mL) under À20 ꢀC for 20 min. The mixture
was allowedto stir for 24 h at 5 ꢀC, andthen con-
centrated in vacuo. To the crude imidate dissolved in
EtOH (10 mL) at ambient temperature was added
ammonium acetate (931 mg, 12.1 mmol). The reaction
mixture was stirredat ambient temperature for 24 h and
concentratedin vacuo. The resulting residue was chro-
matographedon ODS-gel eluting with methanol
(MeOH)/H2O (0:100–10:90). MeOH was removedin
vacuo, andthe aqueous solution was lyophilizedafter
being acidified with 1 N HCl to give 7-amidino-N-ethyl-
N-[4-(4-piperidyloxy)phenyl]-2-naphthamide as a white
Ethyl 3-(N-{4-[(1-tert-butoxycarbonyl-4-piperidyl)oxy]-
phenyl}-N-(7-cyano-2-naphthoyl)amino)propionate (4d).
A
suspended solution of 7-cyano-2-naphthalene-
carboxylic acid( 1) (246 mg, 1.2 mmol) in thionyl chlo-
ride (2.5 mL) was stirred at 90 ꢀC for 4 h. The reaction
mixture was concentratedin vacuo, andto a suspended
solution of the resulting residue in CH2Cl2 (1.3 mL) was
added a solution of 3 (540 mg, 1.4 mmol) in pyridine
(14 mL) and 4-dimethylaminopyridine (17 mg). The
reaction mixture was stirredat 60 ꢀC for 12 h andcon-
centrated in vacuo. The resulting residue was dissolved
in CHCl3 andwashedwith 10% aqueous K 2CO3. The
organic layer was dried over Na2SO4 andconcentrated
in vacuo. The residue was chromatographed on silica
gel eluting with EtOAc/Hex (40:60) to give 4d (450 mg,
66%) as a white solid: mp 115–116 ꢀC; 1H NMR
(CDCl3) d 1.24 (3H, t, J=7.2 Hz), 1.45 (9H, s), 1.59–
1.74 (2H, m), 1.78–1.90 (2H, m), 2.72 (2H, t, J=7.2 Hz),
3.22–3.31 (2H, m), 3.58–3.72 (2H, m), 4.10 (2H, q,
J=7.2 Hz), 4.23 (2H, t, J=7.2 Hz), 4.29–4.39 (1H, m),
6.73 (2H, d, J=8.7 Hz), 7.00 (2H, d, J=8.7 Hz), 7.47
(1H, dd, J=1.5, 8.4 Hz), 7.59 (1H, dd, J=1.5, 8.4 Hz),
7.65 (1H, d, J=8.4 Hz), 7.81 (1H, d, J=8.4 Hz), 7.89
(1H, s), 8.09 (1H, s); FAB MS m/e (M+1)+ 572.
1
amorphous powder (527 mg): H NMR (DMSO-d6) d
1.14 (3H, t, J=7.4 Hz), 1.63–1.80 (2H, m), 1.93–2.08
(2H, m), 2.88–3.05 (2H, m), 3.05–3.20 (2H, m), 3.73–
3.98 (2H, m), 4.45–4.60 (1H, m), 6.86 (2H, d,
J=8.3 Hz), 7.13 (2H, d, J=8.3 Hz), 7.48 (1H, d,
J=7.3 Hz), 7.79–7.90 (2H, m), 8.00–8.10 (2H, m), 8.43
(1H, s), 9.09 (2H, br-s), 9.30 (2H, s), 9.54 (2H, s); FAB
MS m/e (M+1)+ 417.
To a stirred solution of the mono-amidine intermediate
(481 mg) in EtOH (10 mL) andMeOH (10 mL) at
ambient temperature was added ethyl acetimidate
hydrochloride (847 mg, 6.9 mmol) and Et3N (893 mg,
8.8 mmol). The mixture was allowedto stir for 24 h at
ambient temperature, andthen concentratedin vacuo.
The resulting residue was chromatographed on ODS-gel
eluting with MeOH/H2O (0:100–5:95). MeOH was
removedin vacuo, andthe aqueous solution was lyo-
philizedafter being acidifiedwith 1N HCl. 5b (430 mg,
67%) was obtainedas a white amorphous powder: 1H
NMR (DMSO-d6) d 1.15 (3H, t, J=7.2 Hz), 1.55–1.72
(2H, m), 1.89–2.03 (2H, m), 2.27 (3H, s), 3.38–3.55 (2H,
m), 3.61–3.81 (2H, m), 3.81–3.95 (2H, m), 4.53–4.63
(1H, m), 6.86 (2H, d, J=7.8 Hz), 7.14 (2H, d,
Ethyl 4-(N-{4-[(1-tert-butoxycarbonyl-4-piperidyl)oxy]-
phenyl}-N-(7-cyano-2-naphthoyl)amino)buthylate
(4e).
Compound 4e was synthesizedfrom 4a andethyl 4-
bromobutylate according to the same procedure as that
for 4b. Compound 4e was obtainedas a pale yellow
viscous oil (17% yield): 1H NMR (CDCl3) d 1.25 (3H, t,
J=7.2 Hz), 1.45 (9H, s), 1.59–1.73 (2H, m), 1.77–1.88
(2H, m), 2.03 (2H, quintet, J=7.2 Hz), 2.43 (2H, t,

F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
2605
J=7.8 Hz), 7.42–7.54 (1H, m), 7.80–7.90 (2H, m), 8.03–
8.10 (2H, m), 8.43 (1H, s), 8.75 (1H, s), 9.27 (3H, s), 9.52
(2H, s); FAB MS m/e (M+1)+ 458. Anal. calcdfor
3.84 (1H, m), 4.01 (2H, q, J=7.3 Hz), 4.11 (2H, t,
J=6.8 Hz), 4.56–4.63 (1H, m), 6.87 (2H, d, J=8.3 Hz),
7.16 (2H, d, J=8.6 Hz), 7.46 (1H, d, J=7.3 Hz), 7.85–
7.89 (2H, m), 8.02–8.08 (2H, m), 8.49 (1H, s), 8.91 (1H,
s), 9.45 (3H, s), 9.63 (2H, s); FAB MS m/e (M+1)+
ꢁ
C27H31N5O2 2.1HClꢁ 2.5H2O: C, 55.99; H, 6.63; N,
12.09; Cl, 12.85. Found: C, 56.07; H, 6.64; N, 12.22; Cl,
13.02.
ꢁ
530. Anal. calcdfor C 30H35N5O4 2.1HClꢁ 2.5H2O: C,
55.33; H, 6.52; N, 10.75; Cl, 11.43. Found: C, 55.65; H,
6.30; N, 10.46; Cl, 11.26.
N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-7-amidino-
2-naphthamide (5a). Compound 5a was synthesized
from 4a according to the same procedure as that for 5b.
Compound 5a was obtainedas a white amorphous
3-(N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-N-(7-
amidino-2-naphthoyl)amino)propionic acid (5h). A solu-
tion of 5d (705 mg, 1.1 mmol) in 12 N HCl (30 mL) was
stirredat ambient temperature for 5 h. The reaction
mixture was concentratedin vacuo andthe residue was
chromatographedon ODS-gel eluting with CH 3CN/
H2O (0:100–10:90). CH3CN was removedin vacuo, and
the aqueous solution was lyophilizedafter being acid-
ifiedwith 1 N HCl. 5h (592 mg, 87%) was obtainedas a
white amorphous powder: 1H NMR (DMSO-d6) d 1.55–
1.70 (2H, m), 1.89–2.00 (2H, m), 2.28 (3H, s), 2.54–2.61
(2H, m), 3.39–3.55 (2H, m), 3.63–3.70 (1H, m), 3.76–
3.83 (1H, m), 4.03–4.08 (2H, m), 4.55–4.62 (1H, m), 6.86
(2H, d, J=7.8 Hz), 7.17 (2H, d, J=7.8 Hz), 7.44–7.50
(1H, m), 7.84–7.88 (2H, m), 8.02–8.08 (2H, m), 8.47
(1H, s), 8.87 (1H, s), 9.41 (3H, s), 9.60 (2H, s); FAB MS
1
powder (41% yield): H NMR (DMSO-d6) d 1.70–1.85
(2H, m), 2.00–2.14 (2H, m), 2.30 (3H, s), 3.48–3.62 (2H,
m), 3.70–3.85 (2H, m), 4.65–4.73 (1H, m), 7.05 (2H, d,
J=9.2 Hz), 7.76 (2H, d, J=9.2 Hz), 7.94 (1H, dd,
J=8.4, 1.6 Hz), 8.18–8.28 (3H, m), 8.60–8.70 (2H, m),
8.72 (1H, s), 9.20 (3H, s), 9.55 (2H, s), 10.48 (1H, s);
FAB MS m/e (M+1)+ 430. Anal. calcdfor C 25H27N5O2
.
2.1HClꢁ 3.3H2O: C, 53.10; H, 6.36; N, 12.38; Cl, 13.16.
Found: C, 53.07; H, 6.12; N, 12.36; Cl, 13.45.
Ethyl N-{4-[(1-acetimidoyl-4-piperidyl)oxy]phenyl}-N-(7-
amidino-2-naphthoyl)glycinate (5c). Compound 5c was
synthesizedfrom 4c according to the same procedure as
that for 5b. Compound 5c was obtainedas a white
1
ꢁ
amorphous powder (40% yield): H NMR (DMSO-d6)
m/e (M+1)+ 502. Anal. calcdfor C 28H31N5O4 2.4HClꢁ
d 1.24 (3H, t, J=7.2 Hz), 1.53–1.71 (2H, m), 1.88–2.02
(2H, m), 2.27 (3H, s), 3.38–3.55 (2H, m), 3.62–3.82 (2H,
m), 4.17 (2H, q, J=7.2 Hz), 4.53–4.63 (3H, m), 6.86
(2H, d, J=8.4 Hz), 7.17 (2H, d, J=8.4 Hz), 7.45 (1H, d,
J=8.4 Hz), 7.82–7.92 (2H, m), 8.05–8.12 (2H, m), 8.48
(1H, s), 8.78 (1H, s), 9.31 (3H, s), 9.54 (2H, s); FAB MS
1.5H2O: C, 54.59; H, 5.95; N, 11.37; Cl, 13.81. Found:
C, 54.68; H, 6.03; N, 11.15; Cl, 13.86.
4-(N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-N-(7-
amidino-2-naphthoyl)amino)butyric acid (5i). Compound
5i was synthesizedfrom 4e according to the same pro-
cedure as that for 5h. Compound 5i was obtainedas a
white amorphous powder (55% yield): 1H NMR
(DMSO-d6) d 1.53–1.71 (2H, m), 1.72–1.83 (2H, m), 1.88–
2.02 (2H, m), 2.27 (3H, s), 2.27–2.37 (2H, m), 3.37–3.54
(2H, m), 3.60–3.94 (4H, m), 4.52–4.63 (1H, m), 6.86 (2H,
d, J=8.3 Hz), 7.15 (2H, d, J=8.3 Hz), 7.48 (1H, d,
J=6.8 Hz), 7.80–7.89 (2H, m), 8.01–8.10 (2H, m), 8.44
(1H, s), 8.81 (1H, s), 9.34 (3H, s), 9.55 (2H, s); FAB MS
m/e (M+1)+ 516. Anal. calcdfor C 29H33N5O4
ꢁ
1.6HClꢁ 3.0H2O: C, 55.47; H, 6.52; N, 11.15; Cl, 9.03.
Found: C, 55.29; H, 6.43; N, 11.13; Cl, 9.05.
N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-N-(7-ami-
dino-2-naphthoyl)glycine (5g). A solution of 5c (170 mg,
0.27 mmol) in 3 N HCl (50 mL) was stirredat 80 ꢀC for
2 h. The reaction mixture was concentratedin vacuo
andthe resiude was chromatographedon ODS-gel
eluting with MeOH/H2O (0:100–10:90). MeOH was
removedin vacuo, andthe aqueous solution was lyo-
philizedafter being acidifiedwith 1 N HCl. 5g (135 mg,
81%) was obtainedas a white amorphous powder: 1H
NMR (DMSO-d6) d 1.55–1.73 (2H, m), 1.88–2.05 (2H,
m), 2.26 (3H, s), 3.40–3.55 (2H, m), 3.61–3.78 (2H, m),
4.49–4.62 (3H, m), 6.85 (2H, d, J=7.8 Hz), 7.16 (2H, d,
J=7.8 Hz), 7.40–7.49 (1H, m), 7.81–7.90 (2H, m), 8.05–
8.12 (2H, m), 8.46 (1H, s), 8.69 (1H, s), 9.17–9.25 (3H,
m), 9.49 (2H, s), 12.75–13.00 (1H, br); FAB MS m/e
m/e (M+1)+ 516. Anal. calcdfor C 29H33N5O4 2.0HClꢁ
ꢁ
3.0H2O: C, 54.21; H, 6.43; N, 10.90; Cl, 11.03. Found: C,
53.92; H, 6.20; N, 10.90; Cl, 11.41.
4-[(N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-N-(7-
amidino-2-naphthoyl)amino)methyl]benzoic acid (5j).
Compound 5j was synthesizedfrom 4f according to the
same procedure as that for 5h. Compound 5j was
obtainedas a white solid(41% yiel)d:
1H NMR
(DMSO-d6) d 1.46–1.68 (2H, m), 1.84–2.02 (2H, m),
2.14 (3H, s), 3.35–3.55 (2H, m), 3.61–3.84 (2H, m),
4.46–4.59 (1H, m), 5.19 (2H, s), 6.78 (2H, d, J=8.8 Hz),
7.06 (2H, d, J=8.8 Hz), 7.48 (2H, d, J=8.0 Hz), 7.55
(1H, d, J=8.0 Hz), 7.84 (1H, dd, J=2.0, 8.8 Hz), 7.88
(1H, d, J=8.0 Hz), 7.91 (2H, d, J=8.0 Hz), 8.08 (1H, d,
J=8.8 Hz), 8.18 (1H, s), 8.44 (1H, s), 8.56–8.76 (1H, br),
9.09–9.65 (5H, m), 12.70–13.15 (1H, br); FAB MS m/e
(M+1)+ 488. Anal. calcdfor C 27H29N5O4 2.4HClꢁ
ꢁ
2.2H2O: C, 52.76; H, 5.87; N, 11.36; Cl, 13.84. Found:
C, 53.09; H, 6.13; N, 11.60; Cl, 13.88.
Ethyl 3-(N-{4-[(1-acetimidoyl-4-piperidyl)oxy]phenyl}-N-
(7-amidino-2-naphthoyl)amino)propionate (5d). Com-
pound 5d was synthesizedfrom 4d according to the
same procedure as that for 5b. Compound 5d was
obtained as a white amorphous powder (59% yield): 1H
NMR (DMSO-d6) d 1.15 (3H, t, J=7.3 Hz), 1.55–1.70
(2H, m), 1.89–2.01 (2H, m), 2.25 (3H, s), 2.63 (2H, t,
J=6.8 Hz), 3.47–3.55 (2H, m), 3.63–3.70 (1H, m), 3.76–
(M+1)+ 564 . Anal. calcdfor C 33H33N5O4 2.0HClꢁ
ꢁ
3.6H2O: C, 56.51; H, 6.06; N, 9.98; Cl, 10.11. Found: C,
56.29; H, 5.96; N, 10.01; Cl, 9.96.
7-[N-(tert-Butoxycarbonyl)amino]naphthalene-2-carboni-
trile (6). To a stirredsolution of Et 3N (5.58 mL,

2606
F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
40 mmol) in tert-butanol was added 4 A molecular
sieves (ca. 40 mL) andrefluxedfor 30 min. Then
8.47 (1H, s), 8.79 (1H, s), 10.15 (1H, s); FAB MS m/e
(M)+ 507.
2
(5.91 g, 30 mmol) and diphenylphosphoryl azide
(8.09 mL, 37.5 mmol) was added and refluxed for 3.5 h.
The reaction mixture was allowedto cool to ambient
temperature, filteredandconcentratedin vacuo. The
resulting residue was suspended in ether and washed
7-Amidino-N-{4-[(1-acetimidoyl-4-piperidyl)oxy]phenyl}-
naphthalene-2-sulfonamide (5k). Compound 5k was syn-
thesizedfrom 4g according to the same procedure as
that for 5b. Compound 5k was obtainedas a white
1
with H2O, saturatedaqueous NaHCO , 10% aqueous
3
amorphous powder (68% yield): H NMR (DMSO-d6)
citric acid, brine, dried over Na2SO4 andconcentrated
in vacuo to provide 6 (8.42 g) as a white amorphous
powder which was used without further purification: 1H
NMR (CDCl3) d 1.56 (9H, s), 6.77 (1H, s), 7.42–7.52
(2H, m), 7.74–7.85 (2H, m), 8.02–8.13 (2H, m); FAB
MS m/e (M+1)+ 269.
d 1.57–1.72 (2H, m), 1.90–2.20 (2H, m), 2.27 (3H, s),
3.40–3.53 (2H, m), 3.63–3.83 (2H, m), 4.50–4.58 (1H,
m), 6.85 (2H, d, J=9.0 Hz), 7.02 (2H, d, J=9.0 Hz),
7.95 (1H, dd, J=1.2, 8.8 Hz), 7.99 (1H, dd, J=1.6,
8.8 Hz), 8.20–8.28 (2H, m), 8.47 (1H, s), 8.68 (1H, s),
9.20–9.80 (6H, m), 10.30 (1H, br-s); FAB MS m/e
(M+1)+ 466. Anal. calcdfor C 24H27N5O3 2.1HClꢁ
ꢁ
N-{4-[(1-tert-Butoxycarbonyl-4-piperidyl)oxy]phenyl}-7-
cyanonaphthalene-2-sulfonamide (4g). To a stirredsolu-
tion of 6 (8.10 g) in 1,4-dioxane at ambient temperature
was added 4 N HCl–EtOAc (10 mL). The reaction mix-
ture was stirredat ambient temperature for 12 h and
concentrated in vacuo. The residue was suspended in
Et2O, filtered and dried in vacuo. The crude 7-amino-
naphthalene-2-carbonitrile hydrochloride (4.72 g) was
usedin the next step without purification: 1H NMR
(DMSO-d6) d 7.61 (1H, d, J=8.7 Hz), 7.74 (1H, d,
J=8.7 Hz), 7.83 (1H, s), 8.04–8.15 (2H, m), 8.59 (1H, s),
9.50 (3H, br-s); GC MS m/e (M)+ 168.
2.5H2O: C, 49.09; H, 5.85; N, 11.93; S, 5.46; Cl, 12.68.
Found: C, 48.80; H, 5.69; N, 11.93; S, 5.56; Cl, 12.47.
7-Amidino-N-{4-[(1-acetimidoyl-4-piperidyl)oxy]phenyl}-
a stirred
N-ethylnaphthalene-2-sulfonamide (5l). To
solution of 5k (100 mg, 0.17 mmol) in tetrahydrofuran
(2 mL) andEtOH (5 mL) at ambient temperature was
added triphenylphosphine (PPh3) (67 mg, 0.25 mmol)
and diethyl azodicarboxylate (DEAD) (40 mL,
0.25 mmol). After stirring at ambient temperature for
30 h, PPh3 (223 mg, 0.85 mmol) andDEAD (133 mL,
0.85 mmol) was added again and stirred at ambient
temperature for 20 h. The reaction mixture was diluted
with 0.5 N HCl andEtOAc andthe aqueous layer was
concentratedin vacuo. The resulting residue was chro-
To a stirredsolution of the aniline (1.0 g) in acetic acid
(3 mL) andconcdHCl (10 mL) at À10 ꢀC was added
dropwise a solution of NaNO2 in H2O (373 mg/0.5 mL).
The reaction mixture was stirredat À5 ꢀC for 45 min
(diazotization reaction mixture). SO2 gas was bubbled
through acetic acid(30 mL) with stirring at ambient
temperature for 30 min, then to the solution was added
CuCl (1.5 g) andintroduction of SO 2 gas was continued
for a further 30 min. The reaction mixture was cooledto
10 ꢀC and the diazotization reaction mixture was added
to this stirredsolution in portions. After stirring at
ambient temperature for 1 h, the reaction mixture was
matographedon ODS-gel eluting with CH CN/0.005 N
3
aqueous HCl (2:98–6:94). CH3CN was removedin
vacuo, andthe aqueous solution was lyophilizedto give
5l (40 mg, 37%) as a white amorphous powder: 1H
NMR (DMSO-d6) d 1.00 (3H, t, J=7.3 Hz), 1.64–1.81
(2H, m), 1.99–2.11 (2H, m), 2.29 (3H, s), 3.41–3.58 (2H,
m), 3.63 (2H, q, J=7.3 Hz), 3.68–3.88 (2H, m), 4.64–
4.72 (1H, m), 6.97 (4H, s), 7.77 (1H, dd, J=1.5, 8.3 Hz),
8.01 (1H, d, J=1.5, 8.3 Hz), 8.26 (1H, d, J=8.7 Hz),
8.30 (1H, d, J=8.8 Hz), 8.48 (1H, s), 8.72 (2H, s), 9.20–
9.33 (3H, m), 9.57 (2H, s); FAB MS m/e (M+1)+ 466.
Anal. calcdfor C 26H31N5O3Sꢁ 2.6HClꢁ 2.2H2O: C, 49.72;
H, 6.10; N, 11.15; S, 5.11; Cl, 14.68. Found: C, 49.55; H,
6.14; N, 11.44; S, 5.15; Cl, 14.83.
pouredinto ice water andextractedwith Et
organic layer was washedwith H O, saturatedaqueous
2O. The
2
NaHCO3, H2O andrdiedover Na
2SO4, then con-
centratedin vacuo to affordcrude 7-cyanonaphthalen-
2-sulfonyl chloride (0.81 g) which was used without fur-
1
ther purification: H NMR (DMSO-d6) d 7.79 (1H, dd,
3-(2-Chloroethyl)benzonitrile (8). To a stirredsolution of
3-(2-oxoethyl)benzonitrile (7) (1.0 g, 6.89 mmol) in
EtOH (10 mL) at 3 ꢀC was added sodium borohydride
(0.4 g, 10.6 mmol). After the mixture was stirredfor 3 h
at 3 ꢀC, H2O was added and extracted with EtOAc. The
EtOAc extracts were washedwith brine, rdiedover
Na2SO4 andconcentratedin vacuo to give 3-(2-hydroxy-
ethyl)benzonitrile (1.02 g, 100%) as a colorless oil which
J=1.5, 8.4 Hz), 7.90 (1H, dd, J=1.5, 8.4 Hz), 8.01 (1H,
d, J=8.4 Hz), 8.10 (1H, d, J=8.4 Hz), 8.31 (1H, s), 8.68
(1H, s); EI MS m/e (M)+ 251, 253.
To a stirredsolution of 1 (819 mg, 2.8 mmol) in 1,2-
dichloroethane (10 mL) at 3 ꢀC was added pyridine
(234 mL) andthe sulfonyl chloride (700 mg). After stir-
ring for 3 h, the reaction mixture was quenchedwith H 2O
andextractedwith EtOAc. The organic layer was
washedwith brine, driedover Na 2SO4 andconcentrated
in vacuo. The resulting residue was recrystallized from
EtOAc–Hex to afford 4g (881 mg, 62%) as a brown
was usedwithout further purification:
1H NMR
(CDCl3) d 2.90 (2H, t, J=6.5 Hz), 3.90 (2H, q,
J=6.5 Hz), 7.38–7.65 (4H, m).
To a stirredsolution of 3-(2-hydroxyethyl)benzonitrile
(1.17 g, 7.95 mmol) in CH2Cl2 (15 mL) at ambient tem-
perature was added thionyl chloride (0.3 mL,
41.1 mmol) andDMF (20 mg). The mixture was allowed
to warm to 50 ꢀC, stirredfor 1 h andthen concentrated
in vacuo. The resulting residue was suspended in H2O
1
amorphous powder: H NMR (DMSO-d6) d 1.35–1.47
(2H, m), 1.38 (9H, s), 1.74–1.85 (2H, m), 3.04–3.17 (2H,
m), 3.54–3.67 (2H, m), 4.33–4.43 (1H, m), 6.81 (2H, d,
J=8.7 Hz), 6.97 (2H, d, J=8.7 Hz), 7.91 (1H, d,
J=8.7 Hz), 7.96 (1H, d, J=8.7 Hz), 8.18–8.25 (2H, m),

F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
2607
andextractedwith EtOAc. The EtOAc extracts were
dried over Na2SO4 andconcentratedin vacuo to give
(1.26 g, 96%) as a pale brown oil: H NMR (CDCl3) d
3.10 (2H, t, J=6.7 Hz), 3.73 (2H, t, J=6.7 Hz), 7.35–
7.70 (4H, m); GC MS m/e (M)+ 165, 167.
(E)-N-{4-[(1-tert-Butoxycarbonyl-4-piperidyl)oxy]phe-
nyl}-2-(3-cyanophenyl)-ethenesulfonamide (4h). To a
8
1
stirredsolution of 1 (500 mg, 1.72 mmol) in CH2Cl2
(5 mL) at ambient temperature was added pyridine
(0.40 mL, 4.95 mmol), 2-chloro-1-ethanesulfonylchloride
(0.20 mL, 1.90 mmol), 4-dimethylaminopyridine (20 mg).
After stirring at ambient temperature for 20 h, the reac-
tion mixture was concentratedin vacuo. To the result-
ing residue was added citric acid aqueous solution which
2-(3-Cyanophenyl)-N-{4-[(4-piperidyl)oxy]phenyl}ethane-
sulfonamide (9). To a stirredsolution of 8 (1.26 g,
7.61 mmol) in H2O (15 mL) at ambient temperature was
added sodium sulfite (1.20 g, 9.52 mmol). The mixture
was allowedto reflux for 25 h andconcentratedin
vacuo. After the resulting residue was dissolved in ben-
zene, thionyl chloride (0.7 mL, 9.6 mmol) and DMF
(20 mg) was added at ambient temperature. The mixture
was refluxedfor 25 h, pouredinto ice water andextrac-
tedwith EtOAc. The EtOAc extracts were washedwith
brine, dried over Na2SO4 andconcentratedin vacuo to
give 2-(3-cyanophenyl)ethanesulfonyl chloride (1.09 g,
62%) as a brown oil which was usedwithout further
was then extractedwith CHCl . The organic solution
3
was dried over Na2SO4 andconcentratedin vacuo. The
resulting crude N-{4-[(1-tert-butoxycarbonyl-4-piper-
idyl)oxy]phenyl}ethenesulfonamide (10) (0.46 g) was not
stable andusedin the next step without purification:
FAB MS m/e (MÀH)À 381.
To a stirredsolution of PPh (50 mg, 0.19 mmol) in
3
DMF (5 mL) at ambient temperature was added palla-
dium(II) acetate (20 mg, 0.089 mmol) under argon
atmosphere. After stirring at ambient temperature for
5 min, 3-bromobenzonitrile (360 mg, 1.98 mmol), the
DMF solution of crude 10 andEt 3N (0.70 mL,
5.02 mmol) was added and stirred at 140 ꢀC for 17 h.
The reaction mixture was concentratedin vacuo. To the
resulting residue was added H2O followedby extracting
with EtOAc. The organic solution was washedwith
brine, dried over Na2SO4 andconcentratedin vacuo.
The resulting residue was chromatographed on silica gel
eluting with EtOAc/Hex (33:67–50:50) to give 4h
purification. To
a
stirredsolution of
1 (1.50 g,
5.15 mmol) in CH2Cl2 (10 mL) at 0 ꢀC was added pyri-
dine (0.5 mL, 6.18 mmol), the sulfonyl chloride (1.09 g,
4.75 mmol) and 4-dimethylaminopyridine (17 mg). After
the reaction mixture was stirredfor 29 h at ambient
temperature, it was quenchedwith 10% aqueous citric
acidandextractedwith CHCl
3. The CHCl3 extracts
were dried over Na2SO4 andconcentratedin vacuo to
give crude N-{4-[(1-tert-butoxycarbonyl-4-piperidyl)oxy]-
phenyl}-2-(3-cyanophenyl)ethanesulfonamide as a solid.
To the solution of this compoundin EtOAc (15 mL)
was added 4N HCl/EtOAc (10 mL) at 0 ꢀC andthe
reaction mixture was stirredfor 13 h at ambient tem-
1
(0.35 g, 42%) as a white amorphous powder: H NMR
(DMSO-d6) d 1.39 (9H, s), 1.40–1.56 (2H, m) 1.75–1.90
(2H, m), 3.06–3.20 (2H, m), 3.57–3.68 (2H, m), 4.38–
4.50 (1H, m), 6.90 (2H, d, J=8.7 Hz), 7.11 (2H, d, J=
8.7 Hz), 7.38 (1H, d, J=15.3 Hz), 7.43 (1H, d, J=
15.3 Hz), 7.61 (1H, dd, J=7.5, 7.8 Hz), 7.86 (1H, d,
J=7.8 Hz), 8.02 (1H, d, J=7.5 Hz), 8.26 (1H, s),
9.79 (1H, s); FAB MS m/e (MÀH)À 482.
perture. The reaction mixture was quenchedwith H O,
2
neutralizedwith saturatedaqueous NaHCO
and
3
extractedwith MeOH/CHCl 3 (10:90). The extracts were
dried over Na2SO4 andconcentratedin vacuo. The
residue was dissolved in EtOAc and the solution was
washedwith H O andbrine, driedover Na 2SO4, and
2
then concentratedin vacuo. The residue was crystallized
from EtOAc to give 9 (1.09 g, 60%) as a pale brown
(E)-N-{4-[(1-tert-Butoxycarbonyl-4-piperidyl)oxy]phe-
nyl}-2-(3-cyanophenyl)-N-methylethenesulfonamide (4i).
To a stirredsolution of 4h (0.79 g, 1.63 mmol) in DMF
(10 mL) at ambient temperature was added K2CO3
(0.45 g, 3.26 mmol) and methyl iodide (0.35 g,
2.47 mmol). After stirring at ambient temperature for
1 h, the reaction mixture was concentratedin vacuo. The
resulting residue was suspended in H2O andextracted
with EtOAc. The EtOAc extracts were dried over
Na2SO4 andconcentratedin vacuo. The resulting residue
was chromatographedon silica gel eluting with EtOAc/
Hex (25:75–33:67) to give 4i (0.57 g, 70%) as a pale yel-
solid: mp 138–140 ꢀC; H NMR (DMSO-d6) 1.33–1.48
1
(2H, m) 1.83–1.93 (2H, m), 2.52–2.60 (2H, m), 2.88–2.98
(2H, m), 3.01–3.09 (2H, m), 3.28–3.37 (2H, m), 4.25–
4.36 (1H, m), 6.90 (2H, d, J=8.7 Hz), 7.12 (2H, d,
J=8.7 Hz), 7.48 (1H, dd, J=7.8, 8.1 Hz), 7.56 (1H, d,
J=7.8 Hz), 7.67 (1H, d, J=8.1 Hz), 7.71 (1H, s); FAB
MS m/e (M+1)+ 386.
N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-2-(3-amidi-
nophenyl)ethanesulfonamide (5m). Compound 5m was
synthesizedfrom 9 according to the same procedure as
that for 5b. Compound 5m was obtainedas a white
1
low viscous oil: H NMR (DMSO-d6) d 1.40 (9H, s),
1.40–1.56 (2H, m) 1.75–1.95 (2H, m), 3.06–3.20 (2H, m),
3.20 (3H, s), 3.57–3.70 (2H, m), 4.48–4.58 (1H, m), 6.96
(2H, d, J=8.7 Hz), 7.27 (2H, d, J=8.7 Hz), 7.33 (1H, d,
J=15.3 Hz), 7.54 (1H, d, J=15.3 Hz), 7.64 (1H, dd, J=
7.8, 8.1 Hz), 7.89 (1H, d, J=7.8 Hz), 8.07 (1H, d, J=
8.1 Hz), 8.33 (1H, s); FAB MS m/e (M+1)+ 498.
1
amorphous powder (80% yield): H NMR (DMSO-d6)
d 1.65–1.80 (2H, m) 1.95–2.10 (2H, m), 2.32 (3H, s),
3.05–3.13 (2H, m), 3.35–3.43 (2H, m), 3.47–3.65 (2H,
m), 3.68–3.90 (2H, m), 4.60–4.70 (1H, m), 6.97 (2H, d,
J=8.8 Hz), 7.19 (2H, d, J=8.7 Hz), 7.51 (1H, dd,
J=7.9, 8.0 Hz), 7.58 (1H, d, J=7.9 Hz), 7.71 (1H, d,
J=8.0 Hz), 7.73 (1H, s), 8.93 (1H, s), 9.36 (2H, s), 9.48
(3H, s), 9.76 (1H, s); FAB MS m/e (M+1)+ 444. Anal.
calcdfor C 22H29N5O3Sꢁ 2.3HClꢁ 0.8H2O: C, 48.77; H,
6.12; N, 12.93; S, 5.92; Cl, 15.05. Found: C, 48.87; H,
6.31; N, 13.04; S, 5.93; Cl, 15.15.
(E)-N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-2-(3-
amidinophenyl)ethenesulfonamide (5n). Compound 5n
was synthesizedfrom 4h according to the same proce-
dure as that for 5b. Compound 5n was obtainedas a
1
pale yellow amorphous powder (34% yield): H NMR

2608
F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
(DMSO-d6) d 1.60–1.80 (2H, m), 1.92–2.10 (2H, m),
2.28 (3H, s), 3.43–3.61 (2H, m), 3.62–3.75 (1H, m),
3.75–3.85 (1H, m), 4.56–4.68 (1H, m), 6.95 (2H, d,
J=8.8 Hz), 7.15 (2H, d, J=8.8 Hz), 7.42 (2H, br-s), 7.65
(1H, dd, J=7.8, 7.9 Hz), 7.88 (1H, d, J=7.8 Hz), 8.00
(1H, d, J=7.9 Hz), 8.21 (1H, s), 8.84 (1H, s), 9.28–9.44
(3H, m), 9.52 (2H, s), 9.92 (1H, s); FAB MS m/e
(M+1)+ 442. Anal. calcdfor C 22H27N5O3Sꢁ 2.3HClꢁ
1.5H2O: C, 47.83; H, 5.89; N, 12.68; S, 5.80; Cl, 14.76.
Found: C, 47.98; H, 5.99; N, 12.79; S, 5.96; Cl, 15.03.
piperidyl)oxy]anilino}methyl)naphthalene-2-carbonitrile10
according to the same procedure as that for 5b. Com-
pound 5s was obtainedas a pale brown amorphous
1
powder: H NMR (DMSO-d6) 1.15 (3H, t, J=7.3 Hz),
1.52–1.85 (2H, m), 1.85–2.15 (2H, m), 2.29 (3H, s),
3.30–4.00 (6H, m), 4.35–5.13 (3H, br), 6.50–7.20 (4H,
br), 7.50–8.30 (5H, m), 8.44 (1H s), 8.90 (1H, s), 9.42
(3H, s), 9.64 (2H, s), FAB MS m/e (M+1)+ 444. Anal.
calcdfor C 27H33N5Oꢁ 3.0HClꢁ 2.8H2O: C, 53.92; H, 6.64;
N, 11.65; Cl, 17.69. Found: C, 53.85; H, 7.07; N, 11.68;
Cl, 18.07.
(E)-N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-2-(3-
amidinophenyl)-N-methylethenesulfonamide (5o). Com-
pound 5o was synthesizedfrom 4i according to the same
procedure as that for 5b. Compound 5o was obtainedas
a white amorphous powder (51% yield): 1H NMR
(DMSO-d6) d 1.65–1.80 (2H, m), 1.96–2.10 (2H, m),
2.30 (3H, s), 3.23 (3H, s), 3.46–3.60 (2H, m), 3.68–3.77
(1H, m), 3.77–3.86 (1H, m), 4.65–4.74 (1H, m), 7.00
(2H, d, J=8.8 Hz), 7.35 (2H, d, J=8.7 Hz), 7.37 (1H, d,
J=15.1 Hz), 7.59 (1H, d, J=15.1 Hz), 7.68 (1H, dd,
J=7.8, 7.9 Hz), 7.90 (1H, d, J=7.8 Hz), 8.05 (1H, d,
J=7.9 Hz), 8.34 (1H, s), 8.81 (1H, s), 9.33 (3H, br-s),
9.55 (2H, s); FAB MS m/e (M+1)+ 456. Anal. calcdfor
C23H29N5O3Sꢁ 2.1HClꢁ 2.5H2O: C, 47.86; H, 6.30; N,
12.13; S, 5.56; Cl, 12.90. Found: C, 48.03; H, 6.17; N,
12.16; S, 5.55; Cl, 12.86.
N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-N-(5-ami-
dinobenzofuran-2-carbonyl) glycine (5t). Compound 5t
was synthesizedfrom 5-cyanobenzofuran-2-carboxylic
acid16 and 2 according to the same procedure as that for
5g. Compound 5t was obtainedas a white amorphous
powder: 1H NMR (DMSO-d6) 1.77–1.83 (2H, m), 2.00–
2.12 (2H, m), 2.30 (3H, s), 3.35–3.40 (2H, m), 3.70–3.87
(2H, m), 4.47 (2H, s), 4.69–4.77 (1H, m), 6.50 (1H, s),
7.07 (2H, d, J=9.1 Hz), 7.35 (2H, d, J=8.8 Hz), 7.76
(1H, d, J=8.6 Hz), 7.81 (1H, dd, J=1.6, 8.6 Hz), 8.14
(1H, s), 8.77 (1H, s), 9.11 (2H, s), 9.28 (1H, s), 9.36 (2H,
s), 12.95 (1H, s); FAB MS m/e (M+1)+ 478. Anal.
ꢁ
calcdfor C 25H27N5O5 2.0HClꢁ 3.0H2O: C, 49.67; H,
5.84; N, 11.59; Cl, 11.73. Found: C, 49.81; H, 5.72; N,
11.81; Cl, 11.47.
(E)-N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-2-(4-
amidinophenyl)ethenesulfonamide (5p). Compound 5p
was synthesizedaccording to the same procedure as that
for 5n. Compound 5p was obtainedas a white amor-
N-{4-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-N-[(E)-3-
(3-amidinophenyl)acryloyl]glycine (5u). Compound 5u
was synthesizedfrom ( E)-3-cyanocinnamic acid17 and 2
according to the same procedure as that for 5g. Com-
pound 5u was obtainedas a white amorphous powder:
1H NMR (DMSO-d6) 1.70–1.87 (2H, m), 2.01–2.16 (2H,
m), 2.32 (3H, s), 3.45–3.65 (2H, m), 3.70–3.91 (2H, m),
4.38 (2H, s), 4.69–4.80 (1H, m), 6.55 (1H, d, J=
15.7 Hz), 7.10 (2H, d, J=8.8 Hz), 7.31 (2H, d, J=
8.8 Hz), 7.55–7.63 (2H, m), 7.77 (2H, d, J=7.8 Hz), 7.85
(1H, s), 8.84 (1H, s), 9.26 (2H, s), 9.34 (1H, s), 9.43 (2H,
s), 12.6–12.9 (1H, br-s); FAB MS m/e (M+1)+ 464.
1
phous powder: H NMR (DMSO-d6) d 1.60–1.80 (2H,
m) 1.92–2.10 (2H, m), 2.28 (3H, s), 3.44–3.60 (2H, m),
3.62–3.80 (2H, m), 4.55–4.65 (1H, m), 6.94 (2H, d,
J=9.3 Hz), 7.13 (2H, d, J=9.3 Hz), 7.43 (1H, d, J=
15.6 Hz), 7.47 (1H, d, J=15.6 Hz), 7.85 (2H, d, J=
8.3 Hz), 7.94 (2H, d, J=8.3 Hz), 8.70 (1H, s), 9.15 (2H,
s), 9.24 (1H, s), 9.43 (2H, s), 9.85 (1H, s); FAB MS m/e
(M+1)+ 442. Anal. calcdfor C 22H27N5O3Sꢁ 2.0HClꢁ
2.6H2O: C, 47.08; H, 6.14; N, 12.48; S, 5.71; Cl, 12.63.
Found: C, 46.89; H, 5.86; N, 12.32; S, 5.77; Cl, 12.67.
ꢁ
Anal. calcdfor C 25H29N5O4 2.3HClꢁ 3.0H2O: C, 49.93;
H, 6.25; N, 11.64; Cl, 13.56. Found: C, 49.72; H, 5.95;
N, 11.65; Cl, 13.86.
(E)-N-{3-[(1-Acetimidoyl-4-piperidyl)oxy]phenyl}-2-(3-
amidinophenyl)ethenesulfonamide (5q). Compound 5q
was synthesizedaccording to the same procedure as that
for 5n. Compound 5q was obtainedas a white amor-
phous powder: 1H NMR (DMSO-d6) 1.65–1.78 (2H, m)
1.95–2.07 (2H, m), 2.28 (3H, s), 3.48–3.57 (2H, m),
3.66–3.78 (2H, m), 4.58–4.67 (1H, m), 6.72 (1H, d,
J=7.8 Hz), 6.78–6.83 (2H, m), 7.20 (1H, dd, J=7.8,
8.6 Hz), 7.47 (1H, d, J=15.7 Hz), 7.56 (1H, d, J=
15.7 Hz), 7.66 (1H, dd, J=7.8, 8.3 Hz), 7.86 (1H, d, J=
8.3 Hz), 8.03 (1H, d, J=7.8 Hz), 8.22 (1H s), 8.74 (1H,
s), 9.23 (2H, s), 9.28 (1H, s), 9.44 (2H, s), 10.24 (1H, s);
FAB MS m/e (M+1)+ 442. Anal. calcdfor
C22H27N5O3Sꢁ 2.1HClꢁ 1.7H2O: C, 48.15; H, 5.97; N,
12.76; S, 5.84; Cl, 13.57. Found: C, 48.33; H, 6.03; N,
12.78; S, 5.76; Cl, 13.34.
X-ray crystallographic experiment
Crystals of the YM-60828/bovine pancreatic trypsin
complex were preparedusing the same methodas
18
reportedpreviously.
The X-ray diffraction data were
collectedwith a Rigaku R-AXIS IIc image-plate system.
The data set covers 79% of the theoretically calculated
number of reflections up to 2.3 A. The structural ana-
lysis of the inhibitor complex was achievedby the Pat-
terson search methodbasedon a molecular model of the
bovine pancreatic trypsin/NAPAP complex (1PPC).
Model building, electron density calculation, and model
19
refinement were carriedout using program O and
CNX2000 (Accelrys Inc.). The model has been refined
to a crystallographic R-value of 18.3% (Rfree=23.6%)
with good stereochemistry (r.m.s.d. of bonds=0.007 A
ꢀ
7-({4-[(1-Acetimidoyl-4-piperidyl)oxy]-N-ethyl-anilino}-
methyl)naphthalene-2-carboxamidine (5s). Compound 5s
was synthesizedfrom 7-({4-[(1- tert-butoxycarbonyl-4-
andangles=1.4
from ideality). We will deposit the
crystallographic data for this structure in the Protein
Data Bank after this manuscript is accepted.

F. Hirayama et al. / Bioorg. Med. Chem. 10 (2002) 2597–2610
2609
Modeling study
NMR studies. The authors are also grateful to the staff
of the Division of Analytical Science Laboratories for
the elemental analysis andspectral measurements.
YM-60828 was initially placedin the active site of factor
Xa by superimposing the crystal structure of the YM-
60828/trypsin complex on to that of ZK-807834/factor
Xa20 complex (1FJS) using corresponding Ca atoms.
ZK-807834 andtwo water molecules aroundthe active
site were then removedfrom the model because they
seem to have unsuitable contacts with the YM-60828
initial model. After manual adjustment of the position
of the side chains, energy minimization of the complex
model was performed with program DISCOVER
(Accelrys Inc.). YM-60828, water molecules andside
chain atoms within 10 A from YM-60828 were allowed
to move during the minimization.
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The authors deeply acknowledge Dr. Yuuji Mano for
pharmacokinetic studies and Dr. Masaya Orita for

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