Synthesis and structure - Activity relationships of 5-amino-6-fluoro-1-[(1R,2S)-2-fluorocyclopropan-1-yl]-8- methylquinolonecarboxylic acid antibacterials having fluorinated 7-[(3R)-3-(1-aminocyclopropan-1-yl)pyrrolidin-1-yl] substituents

Article abstract of DOI:10.1021/jm020328y

A series of novel 5-amino-6-fluoro-1-[(1R,2S)-2-fluorocyclopropan-1-yl]-8-methylquinolones bearing fluorinated (3R)-3-(1-aminocyclopropan-1-yl)pyrrolidin-1-yl substituents at the C-7 position (2-4) was synthesized to obtain potent drugs for infections cau

Full text of DOI:10.1021/jm020328y

J . Med. Chem. 2003, 46, 1005-1015
1005
Syn th esis a n d Str u ctu r e-Activity Rela tion sh ip s of
5-Am in o-6-flu or o-1-[(1R,2S)-2-flu or ocyclop r op a n -1-yl]-8-m eth ylqu in olon eca r boxylic
Acid An tiba cter ia ls Ha vin g F lu or in a ted
7-[(3R)-3-(1-Am in ocyclop r op a n -1-yl)p yr r olid in -1-yl] Su bstitu en ts1
Hiroaki Inagaki,* Satoru Miyauchi, Rie N. Miyauchi, Haruko C. Kawato, Hitoshi Ohki, Norikazu Matsuhashi,
Katsuhiro Kawakami, Hisashi Takahashi, and Makoto Takemura
Medicinal Chemistry Research Laboratory, Daiichi Pharmaceutical Co. Ltd., 16-13, Kita-Kasai 1-Chome, Edogawa-ku,
Tokyo 134-8630, J apan
Received J uly 26, 2002
A series of novel 5-amino-6-fluoro-1-[(1R,2S)-2-fluorocyclopropan-1-yl]-8-methylquinolones
bearing fluorinated (3R)-3-(1-aminocyclopropan-1-yl)pyrrolidin-1-yl substituents at the C-7
position (2-4) was synthesized to obtain potent drugs for infections caused by Gram-positive
pathogens, which include resistant strains such as methicillin-resistant Staphylococcus aureus
(MRSA), penicillin-resistant Streptococcus pneumoniae (PRSP), and vancomycin-resistant
enterococci (VRE). These fluorinated compounds 2-4 exhibited potent antibacterial activity
comparable with that of a compound bearing a non-fluorinated (3R)-3-(1-aminocyclopropan-
1-yl)pyrrolidine moiety at the C-7 position (1) and had at least 4 times more potent activity
against representative Gram-positive bacteria than ciprofloxacin (CPFX), gatifloxacin (GFLX),
or moxifloxacin (MFLX). Among them, the 7-[(3S,4R)-4-(1-aminocyclopropan-1-yl)-3-fluoropyr-
rolidin-1-yl] derivative 3 ()DQ-113), which showed favorable profiles in preliminary toxicological
and nonclinical pharmcokinetic studies, exhibited potent antibacterial activity against clinically
isolated resistant Gram-positive pathogens.
In tr od u ction
Multidrug-resistant Gram-positive pathogens, such as
methicillin-resistant Staphylococcus aureus (MRSA),
penicillin-resistant Streptococcus pneumoniae (PRSP),
and vancomycin-resistant enterococci (VRE), have be-
come a serious problem in the medical community.2-5
One particular alarming sign is the acquisition of
resistance to vancomycin (VRE and vancomycin-inter-
mediate-resistant staphylococcal strains; VISA), an
antibiotic generally regarded as the agent of last resort
for serious infections.2,4-6 In the field of quinolone
antibacterial agents, various attempts have been made
to obtain potent drugs for resistant Gram-positive bac-
teria, and trovafloxacin (TVFX),7 moxifloxacin (MFLX),8
gemifloxacin (GMFX),9 and gatifloxacin (GFLX)10, etc.
have been developed and introduced into clinical use
over the past several years. Considering that the
incidence of Gram-positive bacterial resistance to anti-
bacterial agents has been growing, however, antibacte-
rial activities of these newer quinolones are not potent
enough and bacteria resistant to those agents will be
problematic in the near future.11,12 There are a few
agents other than quinolones, such as teicoplanin
(TEIC),13 quinupristin/dalfopristin (QPR/DPR),14 and
linezolid,15 which are now available in clinical use, but
they show some problems, e.g., resistance mutations
and/or side effects.5,16 These problems have been the
driving force for the development of new antibacterial
agents that would be applicable to infections caused by
multidrug-resistant Gram-positive pathogens.
F igu r e 1.
In our previous paper, we reported that several
quinolone derivatives bearing 3-(1-amino-1-substituted-
methyl)pyrrolidin-1-yl groups, including the 3-(1-ami-
nocyclopropan-1-yl)pyrrolidin-1-yl substituent, at the
C-7 position showed potent antibacterial activity against
Gram-positive bacteria.17 Although 7-{(3R)-3-(1-ami-
nocyclopropan-1-yl)pyrrolidin-1-yl}quinolone derivatives
exhibit the most potent activity among them, they
possess higher genotoxicity than 7-(piperazin-1-yl)- or
7-(3-aminopyrrolidin-1-yl)quinolone derivatives. The high
genotoxicity of 7-(3-aminomethylpyrrolidin-1-yl)quino-
lone derivatives has also been reported by the other
groups.18-21 As a method to reduce the genotoxicity, we
reported the usefulness of introducing a (1R,2S)-2-
fluorocyclopropan-1-yl substituent into the N-1 position
instead of a cyclopropyl substituent.22-24 In addition,
5-amino-8-methylquinolone derivatives were reported to
exhibit potent antibacterial activity against Gram-
positive bacteria and showed reduced chromosomal
toxicity in comparison with 8-methylquinolone deriva-
tives.25-26 Therefore, we initially designed and synthe-
sized 5-amino-1-[(1R,2S)-2-fluorocyclopropan-1-yl]-8-
methylquinolone having the (3R)-3-(1-aminocyclopropan-
1-yl)pyrrolidin-1-yl substituent at the C-7 position (1,
Figure 1) to obtain a highly potent compound against
* To whom correspondence should be addressed. Phone: (+81)-
3-3680-0151.
daiichipharm.co.jp.
Fax:
(+81)-3-5696-8344.
E-mail:
inagaeeb@
10.1021/jm020328y CCC: $25.00 © 2003 American Chemical Society
Published on Web 02/07/2003

1006 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6
Inagaki et al.
Sch em e 1
Sch em e 2a
a
Reagents: (a) Ac2O, CH(OEt)3, reflux; (b) (1R,2S)-2-fluoro-1-cyclopropylamine p-toluenesulfonic acid salt, Et3N/CH2Cl2; (c) NaH/1,4-
dioxane; (d) H2, Raney Ni (W-6)/MeOH, 1,4-dioxane; (e) concentrated aqueous HCl, AcOH, reflux.
Sch em e 3a
a
Reagents: (a) Zn, BrCH2CO2Et, cat. I2/THF, reflux; (b) (1) SOCl2/pyridine, (2) DBU/CH2Cl2; (c) (1) NBS, AIBN/CCl4, (2)
(S)-1-phenylethylamine, NaHCO3/EtOH, reflux; (d) H2, PtO2/MeOH; (e) silica gel column chromatography; (f) aqueous NaOH/EtOH.
Gram-positive bacteria with reduced genotoxicity. As we
expected, 1 showed highly potent antibacterial activity
but showed a positive response in the micronucleus test
and is toxic in the chromosome injuring test.
yl]-8-methylquinolone-3-carboxylic acid 9 and appropri-
ate (3R)-3-(1-aminocyclopropan-1-yl)pyrrolidines 5-8, of
which the peripheral amino groups were protected by
tert-butoxycarbonyl groups (Scheme 1).
In addition to the benefit of the (1R,2S)-2-fluorocy-
clopropan-1-yl substituent at the N-1 position, we also
found that introduction of a fluorine atom into the C-7
pyrrolidine substituent was also effective in reducing
genotoxicity.27 Thus, we planned to introduce this
strategy into compound 1 and designed and synthesized
three quinolone compounds having the (3R,4R)-4-(1-
aminocyclopropan-1-yl)-3-fluoropyrrolidin-1-yl substitu-
ent (2), (3S,4R)-4-(1-aminocyclopropan-1-yl)-3-fluoro-
pyrrolidin-1-yl substituent (3), or (4R)-4-(1-aminocyclo-
propan-1-yl)-3,3-difluoropyrrolidin-1-yl substituent (4)
at the C-7 position.
The synthesis of 9 is illustrated in Scheme 2. Treat-
ment of ketoester 10, reported by Yoshida,25 with ethyl
orthoformate in acetic anhydride followed by the reac-
tion with (1R,2S)-2-fluoro-1-cyclopropylamine p-tolu-
enesulfonic acid salt in the presence of triethylamine
provided crude enaminoketoester. Cyclization of the
resultant product with NaH in 1,4-dioxane yielded
5-nitroquinolone-3-carboxylate 11. Hydrogenation of the
nitro group of 11 followed by acidic hydrolysis of the
resultant 5-aminoquinolone-3-carboxylate 12 provided
quinolonecarboxylic acid 9.
(3R)-3-(1-Aminocyclopropan-1-yl)pyrrolidin-1-yl sub-
stituents 5-8 were synthesized via 1-(5-oxopyrrolidin-
3-yl)cyclopropanecarboxylate 17a . The synthesis of 17a
is illustrated in Scheme 3. The Reformatsky reaction
of 1-acetylcyclopropanecarboxylate 13 28 with ethyl bro-
moacetate gave hydroxyester 14. The R,â-unsaturated
ester 15 was prepared by chlorination of 14 with thionyl
chloride/pyridine and the subsequent elimination reac-
tion of the chlorinated product with 1,8-diazabicyclo-
[5.4.0]undec-7-ene (DBU). These conditions gave exclu-
In this paper, we report the synthesis, the in vitro
antibacterial activity, and the toxicity profiles of these
5-amino-1-[(1R,2S)-2-fluorocyclopropan-1-yl]-8-meth-
ylquinolones.
Ch em istr y
We planned to synthesize those four compounds 1-4
by aromatic nucleophilic substitution reaction from
5-amino-6,7-difluoro-1-[(1R,2S)-2-fluorocyclopropan-1-

SARs of Antibacterials
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6 1007
Sch em e 4a
a
Reagents: (a) LDA, then (PhSO2) 2NF/THF; (b) LDA, then 2,6-di-tert-butylphenol/THF; (c) aqueous NaOH/EtOH; (d) diphenylphosphoryl
azide, Et3N/toluene, then tert-BuOH.
Sch em e 5a
a
Reagents: (a) Lawesson’s reagent/benzene; (b) Raney Ni (W-6)/EtOH; (c) Cbz-Cl/CH2Cl2; (d) aqueous NaOH/EtOH; (e) diphenylphos-
phoryl azide, Et3N/tert-BuOH.
sively the (E)-isomer. Bromination of the allylic position
of 15 with N-bromosuccinimide (NBS) catalyzed by
azobisisobutyronitrile (AIBN) and treatment of the
resultant bromoester with (S)-1-phenylethylamine pro-
vided cyclized pyrrolinone 16. Hydrogenation of 16
catalyzed by platinum dioxide gave a mixture of two
diastereomers 17a and 17b, which were separated by
silica gel column chromatography (17a /17b ) 3.5:1). The
major isomer 17a was converted to the carboxylic acid
18 by basic hydrolysis to determine the absolute con-
figuration of the C-3 position. Compound 18 was ob-
tained as prisms, and the absolute configuration was
determined to be (3S) by X-ray crystallographic analysis.
Incorporation of fluorine atom(s) into the pyrrolidi-
none ring was achieved as illustrated in Scheme 4. (3S)-
Oxopyrrolidinylester 17a was treated with lithium
diisopropylamide (LDA) followed by N-fluorobenzene-
sulfonimide to provide trans-fluorinated oxopyrrolidin-
ylester 19. The cis-fluorinated compound 20 was syn-
thesized by treatment of 19 with LDA and subsequent
quenching with 2,6-di-tert-butylphenol. To confirm the
configuration of the fluorinated position of the two
fluorinated compounds 19 and 20, 20 was converted to
the tert-butoxycarbonylamino compound 22 by basic
hydrolysis and subsequent Curtius rearrangement reac-
tion using diphenylphosphoryl azide (DPPA) and tert-
butyl alcohol. Compound 22 was analyzed by X-ray
crystallographic analysis, and the configuration of the
fluorinated position was determined to be (4R). Accord-
ingly, the configuration of the fluorinated position of 19
and 20 was determined to be (4S) and (4R), respectively.
Difluorinated compound 21 was synthesized by treat-
ment of 19 with LDA and N-fluorobenzenesulfonimide.
The four oxopyrrolidinylesters 17a , 19, 20, and 21
synthesized above were converted to benzyloxycarbon-
ylpyrrolidine compounds 27a -d , respectively, as shown
in Scheme 5. Treatment of the oxopyrrolidinylesters
17a , 19, 20, 21 with Lawesson’s reagent afforded
thioxopyrrolidinylesters 23a -d , and reduction of the
thioxo moieties by Raney nickel gave pyrrolidinylesters
24a -d . The 1-phenylethyl groups of 24a -d were trans-
formed to benzyloxycarbonyl groups using benzyl chlo-
roformate according to the von Braun conditions to
provide benzyloxycarbonyl compounds 25a -d . Basic
hydrolysis of 25a -d followed by the Curtius rearrange-
ment of the resultant carboxylic acids 26a -d using
DPPA and tert-butyl alcohol provided 27a -d , respec-
tively.
Finally, as illustrated in Scheme 6, the benzyloxy-
carbonyl groups of 27a -d were deprotected by catalytic
hydrogenation, and the resultant crude products of 5-8
and quinolonecarboxylic acid 9 were heated with tri-
ethylamine in DMSO followed by deprotection of tert-
butoxycarbonyl groups under acidic condition to give the
final products 1-4, respectively.
Reference compounds 30 and 31 were synthesized
from 9 and 28 or 29,17 respectively, by the same proce-
dure as described for 1-4, as illustrated in Scheme 7.
Resu lts a n d Discu ssion
The minimum inhibitory concentrations (MICs) of
1-4, 30, and 31 against several representative Gram-

1008 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6
Inagaki et al.
Sch em e 6a
a
Reagents: (a) H2, Pd-C/EtOH; (b) 9, Et3N/DMSO, heat; (c) concentrated aqueous HCl.
Sch em e 7a
a
Reagents: (a) Et3N/DMSO, heat; (b) concentrated aqueous HCl
Ta ble 1. Antibacterial Activities of 1-4, 30, and 31 and the Reference Compounds
MIC, µg/mL
organisms
1
2
3
4
30
31
TVFXa
MFLXa
GFLXa
CPFXa
S. aureus FDA 209-P
S. epidermidis 56500
S. pneumoniae J -24
S. pyogenes G-36
S. mitis IID685
E. faecalis ATCC19433
E. coli NIHJ
e0.003
e0.003
e0.003
e0.003
e0.003
0.013
e0.003
0.025
0.1
e0.003
e0.003
e0.003
e0.003
e0.003
0.013
e0.003
0.013
0.2
e0.003
e0.003
e0.003
e0.003
e0.003
0.025
e0.003
0.013
0.39
e0.003
e0.003
e0.003
e0.003
e0.003
0.013
e0.003
0.013
0.2
e0.003
0.006
0.013
0.013
0.006
0.025
0.013
0.1
e0.003
e0.003
e0.003
e0.003
e0.003
0.025
e0.003
0.025
0.05
0.013
0.05
0.05
0.2
0.1
0.2
e0.003
0.025
0.2
0.013
0.1
0.025
0.2
0.1
0.2
0.006
0.05
0.78
0.05
0.2
0.2
0.39
0.2
0.39
0.006
0.05
0.39
0.05
0.2
0.39
1.56
0.78
0.78
e0.003
0.025
0.05
K. pneumoniae type II
P. aeruginosa PAO1
0.1
a
Abbreviations are as follows: TVFX ) trovafloxacin; MFLX ) moxifloxacin; GFLX ) gatifloxacin; CPFX ) ciprofloxacin.
Ta ble 2. Intravenous Single-Dose Toxicity and
Micronuclei-Forming Toxicity of 1-4, 30, and 31 in Mice
positive and Gram-negative bacteria are summarized
in Table 1, along with the data for TVFX, MFLX, GFLX,
and ciprofloxacin (CPFX)29 for comparison. The synthe-
sized compounds 1-4, 30, and 31 exhibited 2-128 times
more potent activity against Gram-positive bacteria
than the reference quinolones TVFX, MFLX, GFLX, and
CPFX. In particular, 3-(1-amino-1-substituted-methyl)-
pyrrolidine derivatives 1-4 and 31 were at least 4 times
more potent than the newer quinolones TVFX, MFLX,
and GFLX, which were designed for Gram-positive
infections. Against Gram-negative bacteria, except for
P. aeruginosa, 1-4 and 31 exhibited potency compa-
rable with that of TVFX and CPFX. The compounds
possessing fluorinated pyrrolidines at the C-7 position,
2-4, and the non-fluorinated compound 1 showed
almost identical antibacterial activities. Thus, introduc-
tion of fluorine atom(s) to pyrrolidine substituents did
not affect antibacterial activities substantially.
The results of the intravenous single-dose toxicity
study and the micronucleus test are summarized in
Table 2. Concerning the intravenous single-dose toxicity,
compound 1, which possesses the (3R)-3-(1-aminocyclo-
propan-1-yl)pyrrolidin-1-yl substituent at the C-7 posi-
tion, was less toxic than compound 30, which has the
(3R)-3-(aminomethyl)pyrrolidin-1-yl substituent, and
31, which has the (3R,1′S)-3-(1-aminoethyl)pyrrolidin-
1-yl substituent. Compounds 2 and 3, which have mono-
Intravenous Single-Dose Toxicity
mortality (dead/tested)
dose, mg/kg
1
2
3
4
30
31
150
100
50
2/2
2/2
2/2
0/5
0/5
2/2
2/2
2/2
2/2
2/2
2/2
1/5
0/5
NTa
NTa
1/5
NTa
NTa
Micronuclei-Forming Toxicityb
result (dose, mg/kg)
1
2
3
4
30
31
+ (100)
- (50)
- (150)
- (100)
NTa
+ (50)
a
b
NT ) not tested. (+) positive. (-) negative.
Ta ble 3. Solubility of 1-4, 30, and 31 in Water
solubility, µg/mL
1
2
3
4
30
31
39
NTa
291
NTa
404
95
a
NT ) not tested.
fluorinated pyrrolidines, showed different profiles ac-
cording to the configuration of their fluorine atoms.
Compound 2, which has trans-oriented fluoropyrroli-
dine, was more toxic than non-fluorinated compound 1,
while cis-oriented compound 3 was less toxic than 1.

SARs of Antibacterials
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6 1009
Ta ble 4. Antibacterial Activities of 3 (DQ-113) and Reference Compounds against Clinically Isolated Levofloxacin-Resistant MRSA
(LVFX-r MRSA), PRSP, and VRE
LVFX-r MRSAa (74b)
PRSPc (50b)
range, MIC50
µg/mL µg/mL µg/mL
0.5 e0.008-0.015 e0.008
VRE (Van A) (33b)
VRE (Van B) (10b)
range, MIC50 MIC90
µg/mL µg/mL µg/mL µg/mL µg/mL
0.25 0.015-2 0.25 0.25
16
range,
MIC50, MIC90
,
,
MIC90
,
range,
MIC50
,
MIC90
,
,
,
compds
µg/mL
µg/mL µg/mL
µg/mL
3 (DQ-113) e0.004-4
0.12
4
4
2
8
0.015
0.25
0.25
0.06
0.12-2
2-64
2
GFLXd
MFLXd
GMFXd
ABKd
0.12->128
32
16
32
32
2
0.06-0.5
0.06-0.25
0.015-0.06
4-32
0.25
0.12
0.03
32 0.25-32
32 0.12-32
32 0.03-16
64 2->128
2
2
16
0.06-128
0.06-128
4-128
0.5-2
2-32
16
4
16
8
1-32
4->128
1
2
16
32
32
>128
VCMd
1
0.25-0.5
0.12-1
0.5
0.25
1
0.5
0.5
1
>128
>128
>128 8->128 >128
>128
TEICd
0.06-4
0.25-1
2
0.5
0.5
2
1
0.5
2
8-128
0.25-16
2
32
0.5
2
64 0.25-2
1
0.5
2
2
8
2
QPR/DPRd
LNZd
0.5-1
0.25-0.5
8
2
0.5-16
0.5
0.5
2
a
b
d
MIC range of levofloxacin is 0.5-128 µg/mL. No. of strains. c MIC range of benzylpenicillin is 1-4 µg/mL. Abbreviations are as
follows: GFLX ) gatifloxacin; MFLX ) moxifloxacin; GMFX ) gemifloxacin; ABK ) arbekacin; VCM ) vancomycin; TEIC ) teicoplanin;
QPR/DPR ) quinupristin/dalfopristin; LNZ ) linezolid.
Ta ble 5. Pharmacokinetic Parameters of 3 (DQ-113)
Con clu sion
Intravenously Administered to Rats at a Dose of 20 mg/kg30
We synthesized a series of novel 5-amino-6-fluoro-1-
[(1R,2S)-2-fluorocyclopropan-1-yl]-8-methylquinolones
parameters (units)a
C5min
(µg/mL or
µg/g)
AUC0-6h
(µg‚h/mL or
µg‚h/g)
bearing fluorinated (3R)-3-(1-aminocyclopropan-1-yl)-
pyrrolidin-1-yl substituents at the C-7 position. The
fluorinated compounds 2-4 exhibited potent antibacte-
rial activity comparable with the non-fluorinated com-
pound 1 and at least 4 times more potent activity
against Gram-positive bacteria than the reference quin-
olones. In addition, they showed no micronuclei-forming
toxicity. Among the fluorinated compounds, cis-oriented
derivative 3 (DQ-113) showed reduced intravenous
single-dose toxicity in comparison with 1 and a good
pharmacokinetic profile in rats and exhibited compa-
rable or greater antibacterial activity against clinically
isolated resistant Gram-positive bacteria in comparison
with the other quinolones tested, vancomycin, teicopla-
nin, quinupristin/dalfopristin, and linezolid. Compound
3 has been found to exhibit excellent antibacterial
activity against other clinically isolated bacteria32 in
addition to those we describe in this paper and was
selected for further preclinical evaluation.
t1/2
(h)
AUC ratio
(tissue/serum)
tissue
serum
liver
kidney
lung
11.1
46.2
33.7
22.0
1.1
1.3
1.3
0.9
9.3
36.0
34.8
37.9
1.0
3.9
3.7
4.1
a
Mean values of four animals.
Difluorinated compound 4 showed almost the same
toxicity as 1. Concerning the micronuclei-forming toxic-
ity, the non-fluorinated compounds 1 and 31 showed a
positive response, even though they have the 5-amino-
8-methyl substituent combination and the (1R,2S)-2-
fluorocyclopropan-1-yl group at the N-1 position, which
are reported to reduce genotoxicity.21-26 Compounds
2-4, which have the fluorinated pyrrolidines, showed
negative responses as we expected. The results indicate
the advantage of introducing fluorine atom(s) into the
pyrrolidine substituent at the C-7 position for reducing
micronuclei-forming toxicity as we described before.27,30
Exp er im en ta l Section
Table 3 shows the solubility of these compounds in
water. The fluorinated compound 3 was more soluble
than the non-fluorinated compound 1. These data
indicate that the fluorine atom contributes to improving
solubility in water.
Gen er a l. Unless otherwise noted, materials were obtained
from commercial suppliers and used without further purifica-
tion. Melting points were taken on a Yanako MP-500D melting
point apparatus and are uncorrected. Optical rotations were
measured in a 0.5 dm cell at 25 °C at 589 nm with a HORIBA
1
SEPA-300 polarimeter. H NMR spectra were determined on
The MICs against clinically isolated resistant Gram-
positive bacteria of compound 3 (DQ-113), which exhib-
ited the lowest single-dose toxicity and a negative
response in the micronucleus test, were determined, and
the results are shown in Table 4. Compound 3 exhibited
more potent activity than the other quinolone antibacte-
rial agents (GFLX, MFLX, and GMFX), VCM, TEIC,
and LNZ, and the activity was comparable with QPR/
DPR against levofloxacin-resistant MRSA. Against PRSP,
3 exhibited the most potent activity among the listed
compounds. Compound 3 also exhibited the most potent
activity against both strains of VRE (Van A strains and
Van B strains) among the listed compounds.
a J EOL J NM-EX400 spectrometer. Chemical shifts are re-
ported in parts per million relative to tetramethylsilane or
sodium 2,2-dimethyl-2-silapentane-5-sulfonate as internal stan-
1
dards. Significant H NMR data are tabulated in the following
order: number of protons, multiplicity (s, singlet; d, doublet;
t, triplet; q, quartet; m, multiplet), coupling constant(s) in
hertz. High-resolution mass spectra were obtained on a J EOL
J MS-700 mass spectrometer under electron impact ionization
conditions (EI), electron spray ionization conditions (ESI), or
fast atom bombardment ionization conditions (FAB). Elemen-
tal analyses are indicated only by the symbols of the elements;
analytical results were within 0.4% of the theoretical values
unless otherwise noted. Column chromatography refers to
flash column chromatography conducted on Merck silica gel
60, 230-400 mesh ASTM. Thin-layer chromatography (TLC)
was performed with Merck silica gel 60 F254 TLC plates, and
compound visualization was effected with a 5% solution of
molybdophosphoric acid in ethanol, UV lamp, iodine, or Wako
ninhydrin spray.
The pharmacokinetic profile of compound 3 after
intravenous administration (20 mg/kg) to rats is shown
in Table 5. Compound 3 exhibited high plasma concen-
tration, and the area under the time-concentration
curve (AUC) and showed a good distribution pattern in
liver, kidney, and lung.31
In Vitr o An tiba cter ia l Activity. The MICs of the com-
pounds tested in this study were determined by the 2-fold

1010 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6
Inagaki et al.
micro broth dilution method using Mueller-Hinton broth
(Difco Laboratories, Detroit, MI) with an inoculum size of
approximately 105 CFU per well. The MIC was defined as the
lowest concentration that prevented visible bacterial growth
after incubation at 37 °C for 18 h.
in 150 mL of 1,4-dioxane on an ice bath was added NaH (60%
mineral oil dispersion, 3.23 g, 80.7 mmol) portionwise. The
mixture was stirred at ambient temperature for 1 h. After the
mixture was poured into ice-cooled 5 N aqueous HCl, the
precipitate was collected by filtration and washed with water
(3×) to give the crude product. Recrystallization from CHCl3/
EtOH gave pure 11 (13.9 g, 70%) as a colorless powder, mp
230-231 °C. 1H NMR (CDCl3): δ 1.35-1.45 (1H, m), 1.38 (3H,
t, J ) 7.3 Hz), 1.58-1.70 (1H, m), 2.75 (3H, d, J ) 3.4 Hz),
3.85-3.93 (1H, m), 4.37 (2H, q, J ) 7.3 Hz), 4.80-4.83 and
4.95-4.99 (1H, m), 8.57 (1H, d, J ) 2.9 Hz). Anal. (C16H13F3-
N2O5) C, H, N. [R]D -124.0° (c 0.325, DMSO).
In tr a ven ou s Sin gle-Dose Toxicity. The test compounds
were dissolved in 0.1 N NaOH in saline at different concentra-
tions. The solution was administered intravenously to 5-week-
old male Slc:ddY mice at a speed of 0.2 mL/min. The total
volume of administration was adjusted to 10 mL/kg of body
weight. The number of dead mice was counted on day 7.
Micr on u cleu s Test. Five-week-old male Slc:ddY mice were
used in this test. The test compounds were dissolved in 0.1 N
NaOH in saline, and the solution was administered intrave-
nously in each group of mice. At 24 and 48 h after treatment,
approximately 5 µL of peripheral blood was collected from a
tail blood vessel of each mice. The blood was dropped onto an
acridine orange coated glass slide and covered immediately
with a coverslip. For each animal, 1000 reticulocytes were
examined for micronuclei by fluorescence microscopy, and the
frequency of micronucleated reticulocytes (MNRET) was ex-
pressed as a percentage. Statistical analysis was performed
with the Kastenbaum and Bowman method.33
P h a r m a cok in etic Stu d ies. Seven-week-old male Crj:CD
rats (n ) 4) were used. The animals were administered drug
samples in a single intravenous dose (20 mg/kg) as an aqueous
solution. The concentrations of the compounds were deter-
mined by a microbiological assay (agar well dilution method)
using B. subtilis ATCC 6051. The mean values of the four rats
were shown.
X-r a y Cr ysta llogr a p h ic Stu d y. All measurements were
made on a Rigaku AFC7R diffractometer (Cu KR radiation,
λ ) 1.541 78 Å, graphite monochromator, ω-2θ scans,
2θmax ) 120.1°). The crystal data and parameters are sum-
marized below. The structures were solved by direct methods
and refined by full-matrix least-squares and Fourier tech-
niques. The non-hydrogen atoms were refined anisotropically.
The hydrogen atoms were refined isotropically (dC-H ) 0.95
Å), and hydrogen positions were calculated by assuming ideal
geometries. The acidic hydrogen atom of 18 was refined with
respect to its coordinates. All calculations were performed by
using the teÌsan crystallographic software package of Molec-
ular Structure Corporation.
E t h yl 5-Am in o-6,7-d iflu or o-1-[(1R,2S)-2-flu or ocyclo-
p r op a n -1-yl]-1,4-d ih yd r o-8-m eth yl-4-oxoqu in olin e-3-ca r -
boxyla te (12). 11 (13.9 g, 37.6 mmol) was suspended in 500
mL of methanol and 500 mL of 1,4-dioxane. Raney Ni (200
mL) was added to the suspension, and the suspension was
stirred at ambient temperature for 10 min. The suspension
was filtered and concentrated in vacuo. The residue was
dissolved in 300 mL of CHCl3, filtered through Celite, and
concentrated in vacuo to give 12 (12.5 g, 98%) as a yellow
1
powder, mp 187-189 °C. H NMR (CDCl3): δ 1.25-1.38 (1H,
m), 1.39 (3H, t, J ) 7.3 Hz), 1.45-1.59 (1H, m), 2.46 (3H, d,
J ) 2.4 Hz), 3.73-3.79 (1H, m), 4.38 (2H, q, J ) 7.3 Hz), 4.73-
4.75 and 4.88-4.92 (1H, m), 6.99 (2H, br s), 8.40 (1H, d, J )
3.4 Hz). Anal. (C16H15F3N2O3) C, H, N. [R]D -240.9° (c 0.560,
DMSO).
5-Am in o-6,7-d iflu or o-1-[(1R,2S)-2-flu or ocyclop r op a n -
1-yl]-1,4-d ih yd r o-8-m et h yl-4-oxoq u in olin e-3-ca r b oxylic
Acid (9). A mixture of 12 (10.43 g, 30.6 mmol), 150 mL of
AcOH, and 150 mL of concentrated aqueous HCl was heated
for reflux for 1 h. After the mixture was cooled, 700 mL of
cold water was added and the precipitate was collected by
filtration. The resultant solid was washed with water (2×),
EtOH, and Et2O and then dried with a vacuum pump to give
1
9 (7.52 g, 79%) as a yellow powder, mp 293-297 °C (dec). H
NMR (0.1 N NaOD/D2O): δ 1.31-1.42 (1H, m), 1.53-1.68 (1H,
m), 2.52 (3H, s), 4.03-4.10 (1H, m), 4.85-4.93 and 5.05-5.10
(1H, m), 8.32 (1H, s). Anal. (C14H11F3N2O3) C, H, N. [R]D
-163.0° (c 0.460, DMSO).
Eth yl 3-(1-Eth oxycar bon ylcyclopr opan -1-yl)-3-h ydr oxy-
bu ta n oa te (14). To a solution of ethyl 1-acetylcyclopropane-
carboxylate (13) (61.7 g, 0.39 mol) in 500 mL of PhH was added
Zn powder (13 g, 0.20 mol) and a catalytic amount of I2. To
the mixture, heated for reflux, a solution of ethyl bromoacetate
(56.2 mL, 0.51 mol) in 100 mL of PhH was added dropwise
carefully. When the reaction started, the addition was sus-
pended and Zn powder (39 g, 0.61 mol) was added to the
reaction vessel portionwise. Then the rest of the ethyl bro-
moacetate solution was slowly added dropwise and the mixture
was heated for reflux for another 2 h. The mixture was cooled
to ambient temperature, and 500 mL of 1 N aqueous HCl was
added to the mixture. The resultant suspension was filtered
through Celite, and the organic layer was separated. The
organic solution was washed with brine (2×), dried over Na2-
SO4, and concentrated to give 15 (90.3 g, 95%) as a colorless
oil. 1H NMR (CDCl3): δ 1.08-1.18 (4H, m), 1.23 (3H, t, J )
6.8 Hz), 1.27 (3H, t, J ) 6.8 Hz), 1.43 (3H, s), 2.91 (1H, d, J )
15.1 Hz), 2.98 (1H, d, J ) 15.1 Hz), 4.09 (2H, q, J ) 6.8 Hz),
4.19 (2H, q, J ) 6.8 Hz). High-resolution MS (FAB) calcd for
Cr ysta l Da ta a n d Str u ctu r e An a lysis. For 18, a colorless
prism-shaped crystal was formed from AcOEt: C16H19NO3;
FW ) 273.33; sample dimensions, 0.30 mm × 0.25 mm × 0.13
mm; orthorhombic, space group P212121; a ) 11.156(1) Å, b )
20.549(1) Å, c ) 6.4714(7) Å, V ) 1483.5(2) Å3, Z ) 4; dcalcd
)
1.224 g/cm3; F000 ) 584; µ ) 6.85 cm-1. The final cycle of full-
matrix least squares refinement was based on 1312 observed
reflections and 186 variable parameters and converged at
R ) 0.042 (Rw ) 0.107).
For 22, a colorless prism-shaped crystal was formed from
n-hexane/CH2Cl2: C20H27FN2O3; FW ) 362.44; sample dimen-
sions, 0.15 mm × 0.25 mm × 0.25 mm; orthorhombic, space
group P212121; a ) 12.186(1) Å, b ) 15.8918(9) Å, c ) 10.682-
(1) Å, V ) 2068.7(2) Å3, Z ) 4; dcalcd ) 1.164 g/cm3; F000 ) 776;
µ ) 6.92 cm-1. The final cycle of full-matrix least squares
refinement was based on 1595 observed reflections and 237
variable parameters and converged at R ) 0.052 (Rw ) 0.099).
E t h yl 6,7-Diflu or o-1-[(1R,2S)-2-flu or ocyclop r op a n -1-
yl]-1,4-d ih yd r o-8-m et h yl-5-n it r o-4-oxoq u in olin e-3-ca r -
boxyla te (11). A mixture of ethyl 2,4,5-trifluoro-3-methyl-6-
nitrobenzoylacetate (10) (16.4 g, 53.8 mmol), ethyl orthoformate
(17.9 mL, 107.6 mmol), and 29 mL of Ac2O was heated at 100
°C for 2 h. The mixture was concentrated in vacuo to give a
brown oil. To a stirred solution of the brown oil in 200 mL of
toluene in an ice bath was added (1R,2S)-2-fluorocyclopropyl-
amine p-toluenesulfonic acid salt (16.0 g, 64.7 mmol), and then
a solution of triethylamine (10.9 mL, 78.0 mmol) in 30 mL of
toluene was added dropwise. Stirring was continued for 2 h
in the ice bath. The mixture was diluted with AcOEt, and the
solution was washed with water and brine (2×), dried over
Na2SO4, and concentrated. To a stirred solution of the residue
C
12H20O5 + H: 245.1389. Found: 245.1382.
Eth yl (E)-3-(1-Eth oxyca r bon ylcyclop r op a n -1-yl)-2-bu -
ten oa te (15). To a solution of 14 (90.3 g, 0.37 mol) in pyridine
(182 mL, 2.25 mol) at -10 °C, thionyl chloride (35.1 mL, 0.48
mmol) was added dropwise. The mixture was stirred at this
temperature for 3 h and then poured into ice water. The
mixture was extracted with CH2Cl2 (3×), and the combined
organic layer was washed with 1 N aqueous HCl and brine
and was dried over Na2SO4. Then DBU (58 mL, 0.39 mol) was
added dropwise to the solution at 0 °C and the mixture was
stirred at ambient temperature for 18 h. The resultant solution
was washed with 1 N aqueous HCl and brine and was dried
over Na2SO4, and the residue was purified by column chro-
matography, eluting with AcOEt/hexane ) 1:9 to yield 15 (56.6

SARs of Antibacterials
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6 1011
g, 68%) as a colorless oil. 1H NMR (CDCl3): δ 1.01 (2H, dd,
J ) 3.9, 6.8 Hz), 1.24 (3H, t, J ) 7.3 Hz), 1.28 (3H, t, J ) 7.3
Hz), 1.40 (2H, dd, J ) 3.9, 6.8 Hz), 2.29 (3H, d, J ) 1.5 Hz),
4.13 (2H, q, J ) 7.3 Hz), 4.16 (2H, q, J ) 7.3 Hz), 5.78 (1H, d,
of anhydrous THF at -78 °C over 10 min. The mixture was
stirred at -10 °C for 20 min and then cooled to -78 °C. To
the mixture was added a solution of 17a (7.05 g, 23.4 mmol)
in 30 mL of anhydrous THF dropwise at -78 °C over 15 min.
After the mixture was stirred at -78 °C for 1 h, a solution of
N-fluorobenzenesulfonimide (11.81 g, 37.4 mmol) in 60 mL of
anhydrous THF was added dropwise to the mixture at -78
°C over 25 min. The mixture was stirred for 2 h at -78 °C
followed by 20 min at room temperature. The reaction was
quenched with saturated aqueous NH4Cl, and the organic
layer was separated. The aqueous layer was extracted with
diethyl ether (2×), and the organic layers were combined and
washed with water (3×), dried over anhydrous MgSO4, and
concentrated in vacuo. The crude product was purified by silica
gel column chromatography, eluting with AcOEt/hexane ) 1:3
J ) 1.0 Hz). High-resolution MS (FAB) calcd for C12H18O4
+
H: 227.1283. Found: 227.1283.
Eth yl 1-{2,5-Dih yd r o-5-oxo-1-[(S)-1-p h en yleth yl]-1H-
p yr r ol-3-yl}cyclop r op a n eca r boxyla te (16). To a solution
of 15 (25.4 g, 0.11 mol) in 300 mL of CCl4 was added
N-bromosuccinimide (23.9 g, 0.13 mol) and a catalytic amount
of 2,2′-azobisisobutyronitrile, and the mixture was heated to
reflux for 5 h. The mixture was filtrated and concentrated in
vacuo. The residue was dissolved in 250 mL of EtOH and
NaHCO3 (18.8 g, 0.22 mol), and then (S)-1-phenylethylamine
(15.8 mL, 0.12 mol) was added dropwise at ambient temper-
ature. The mixture was stirred at this temperature for 30 min
and then heated to reflux for 4 h. The mixture was concen-
trated in vacuo, AcOEt was added to the residue, and then
the solution was washed with water, 1 N aqueous HCl (2×),
and brine (2×) and dried over Na2SO4. The residue was
purified by column chromatography, eluting with AcOEt/
hexane ) 1:1 to yield 16 (13.1 g, 39%) as a colorless oil. 1H
NMR (CDCl3): δ 1.13-1.15 (2H, m), 1.18 (3H, t, J ) 6.8 Hz),
1.60 (3H, d, J ) 7.3 Hz), 1.61-1.64 (2H, m), 3.80 (1H, d, J )
19.5 Hz), 4.09 (2H, q, J ) 6.8 Hz), 4.13 (1H, q, J ) 19.5 Hz),
5.56 (1H, q, J ) 7.3 Hz), 5.85 (1H, t, J ) 1.5 Hz), 7.25-7.37
(5H, m). High-resolution MS (FAB) calcd for C18H21NO3 + H:
300.1600. Found: 300.1609. [R]D -56.5° (c 0.536, CHCl3).
Eth yl 1-{(3S)-5-Oxo-1-[(S)-1-p h en yleth yl]p yr r olid in -3-
yl}cyclop r op a n eca r boxyla te (17a ) a n d Eth yl 1-{(3R)-5-
Oxo-1-[(S)-1-p h en yleth yl]p yr r olid in -3-yl}cyclop r op a n e-
ca r boxyla te (17b). To a solution of 16 (12.1 g, 40.5 mmol) in
300 mL of MeOH was added PtO2 catalyst (400 mg), and the
mixture was stirred at ambient temperature for 18 h under a
hydrogen atmosphere. The mixture was filtered and concen-
trated in vacuo to give a colorless oil. The oil was separated
into two diastereomers by column chromatography, eluting
with AcOEt/hexane ) 2:3. 17a (9.0 g, 74%) was a pale-yellow
oil. 1H NMR (CDCl3): δ 0.63-0.65 (2H, m), 1.13 (3H, t, J )
7.1 Hz), 1.12-1.19 (2H, m), 1.52 (3H, d, J ) 7.3 Hz), 2.17 (1H,
dd, J ) 9.0, 16.8 Hz), 2.46 (1H, dd, J ) 9.3, 16.3 Hz), 2.67-
2.76 (2H, m), 3.47 (1H, t, J ) 8.3 Hz), 3.96-4.11 (2H, m), 5.51
(1H, q, J ) 7.3 Hz), 7.26-7.35 (5H, m). High-resolution MS
(EI) calcd for C18H23NO3: 301.1678. Found: 301.1684. [R]D
-96.5° (c 1.291, CHCl3). 17b (2.6 g, 21%) was a pale-yellow
oil. 1H NMR (CDCl3): δ 0.72-0.76 (2H, m), 1.18-1.24 (2H,
m), 1.21 (3H, t, J ) 7.1 Hz), 1.52 (3H, d, J ) 7.1 Hz), 2.27-
2.32 (1H, m), 2.44-2.52 (2H, m), 3.14 (2H, d, J ) 8.0 Hz), 4.10
(2H, q, J ) 7.1 Hz), 5.50 (1H, q, J ) 7.1 Hz), 7.26-7.35 (5H,
m).
1
to yield 19 (5.28 g, 71%) as a colorless oil. H NMR (CDCl3):
δ 0.76-0.81 (1H, m), 0.89-0.93 (1H, m), 1.09 (3H, t, J ) 6.8
Hz), 1.24-1.34 (2H, m), 1.58 (3H, d, J ) 7.3 Hz), 2.23 (1H, dq,
J ) 8.3, 28.3 Hz), 2.88-2.93 (1H, m), 3.48 (1H, t, J ) 9.3 Hz),
3.92-4.08 (2H, m), 5.14 (1H, dd, J ) 7.8, 53.7 Hz), 5.54 (1H,
q, J ) 7.3 Hz), 7.27-7.34 (5H, m). High-resolution MS (ESI)
calcd for C18H22FNO3 + H: 320.3786. Found: 320.3762. [R]D
-103.1° (c 0.220, CHCl3).
Eth yl 1-{(3S,4S)-4-F lu or o-5-oxo-1-[(S)-1-p h en yleth yl]-
p yr r olid in -3-yl}cyclop r op a n eca r boxyla te (20). Under a
nitrogen atmosphere, n-butyllithium solution (1.68 M in
hexane, 28.1 mL, 47.2 mmol) was added dropwise to a stirred
solution of diisopropylamine (7.22 mL, 51.5 mmol) in 100 mL
of anhydrous THF at -78 °C over 15 min. The mixture was
stirred at 0 °C for 10 min and then cooled to -78 °C. To the
mixture was added a solution of 19 (13.72 g, 43.0 mmol) in 40
mL of anhydrous THF dropwise at -78 °C over 20 min. After
the mixture was stirred at -78 °C for 20 min, a solution of
2,6-di-tert-butylphenol (10.63 g, 51.5 mmol) in 40 mL of
anhydrous THF was added dropwise to the mixture at -78
°C over 20 min. The mixture was stirred for 10 min at -78 °C
and then warmed to ambient temperature. The reaction was
quenched with saturated aqueous NH4Cl at 0 °C, and the
organic layer was separated. The aqueous layer was extracted
with diethyl ether (2×), and the organic layers were combined
and washed with water (2×), dried over anhydrous Na2SO4,
and concentrated in vacuo. The crude product was purified
by silica gel column chromatography, eluting with AcOEt/
1
hexane ) 1:3 to yield 20 (10.19 g, 74%) as a colorless oil. H
NMR (CDCl3): δ 0.57-0.63 (1H, m), 0.78-0.84 (1H, m), 1.07-
1.13 (1H,m), 1.23-1.29 (1H, m), 1.26 (3H, t, J ) 7.1 Hz), 1.54
(3H, d, J ) 7.3 Hz), 2.59 (1H, t, J ) 9.8 Hz), 3.05 (1H, dq, J )
8.3, 28.8 Hz), 3.25 (1H, t, J ) 9.8 Hz), 4.00-4.16 (2H, m), 5.15
(1H, dd, J ) 6.4, 52.7 Hz), 5.53 (1H, q, J ) 7.3 Hz), 7.27-7.38
(5H, m). High-resolution MS (EI) calcd for C18H22FNO3:
319.1584. Found: 319.1579. [R]D -188.1° (c 0.521, CHCl3).
1-{(3S)-5-Oxo-1-[(S)-1-p h en yleth yl]p yr r olid in -3-yl}cy-
clop r op a n eca r boxylic Acid (18). To a solution of 17a (10.5
g, 34.9 mmol) in 70 mL of EtOH was added 1 N aqueous NaOH
(70 mL, 70.0 mmol) at ambient temperature, and the mixture
was stirred at this temperature for 15.5 h and then at 40 °C
for 3 h. The reaction mixture was concentrated in vacuo, and
the residual aqueous solution was washed with AcOEt. Then
the aqueous layer was acidified with concentrated aqueous HCl
under ice cooling, and the mixture was extracted with CHCl3
(3×). The combined organic layer was dried over Na2SO4 and
concentrated in vacuo to give 18 (9.4 g, 99%) as a white solid.
Recrystallization from AcOEt gave colorless prisms, and the
crystals were analyzed by X-ray crystallography. 1H NMR
(CDCl3): δ 0.72-0.74 (2H, m), 1.21-1.23 (2H, m), 1.52 (3H,
d, J ) 7.3 Hz), 2.17 (1H, dd, J ) 8.8, 16.8 Hz), 2.48 (1H, dd,
J ) 9.5, 16.8 Hz), 2.66-2.78 (2H, m), 3.50 (1H, t, J ) 9.3 Hz),
5.51 (1H, q, J ) 7.3 Hz), 7.25-7.34 (5H, m). High-resolution
MS (EI) calcd for C16H19NO3: 273.1365. Found: 273.1361. [R]D
-120.2° (c 0.745, CHCl3).
Eth yl 1-{(3S)-4,4-Diflu or o-5-oxo-1-[(S)-1-p h en yleth yl]-
p yr r olid in -3-yl}cyclop r op a n eca r boxyla te (21). Following
the procedures as described for 19, the title compound was
prepared in 69% yield from 19 as a colorless oil. 1H NMR
(CDCl3): δ 0.76-0.82 (1H, m), 0.87-0.94 (1H, m), 1.09 (3H, t,
J ) 6.8 Hz), 1.23-1.36 (2H, m), 1.58 (3H, d, J ) 7.3 Hz), 2.56-
2.69 (1H, m), 2.92-2.98 (1H, m), 3.53 (1H, td, J ) 2.9, 10.9
Hz), 3.84-3.92 (1H, m), 4.02-4.10 (1H, m), 5.53 (1H, q, J )
7.3 Hz), 7.28-7.35 (5H, m). High-resolution MS (ESI) calcd
for C18H21F2NO3 + H: 338.3690. Found: 338.3702. [R]D -61.8°
(c 0.542, CHCl3).
(3S,4R)-4-[1-(ter t-Bu toxyca r bon yla m in o)cyclop r op a n -
1-yl]-3-flu or o-2-oxo-1-[(S)-1-p h en yleth yl]p yr r olid in e (22).
To a solution of 20 (12.6 g, 39.3 mmol) in 120 mL of EtOH
was added 1 N aqueous NaOH (120 mL, 120.0 mmol) at
ambient temperature, and the mixture was stirred at 40 °C
for 6 h. The reaction mixture was concentrated in vacuo, and
the residual aqueous solution was washed with CHCl3 (2×).
Then the aqueous layer was acidified with 1 N aqueous HCl
under ice cooling, and the mixture was extracted with CHCl3
(2×) and Et2O. The combined organic layer was dried over Na2-
SO4 and concentrated in vacuo to give colorless needles (10.2
g). To a solution of the colorless needles (3.66 g) in 100 mL of
Eth yl 1-{(3S,4R)-4-F lu or o-5-oxo-1-[(S)-1-p h en yleth yl]-
p yr r olid in -3-yl}cyclop r op a n eca r boxyla te (19). Under a
nitrogen atmosphere, n-butyllithium solution (1.68 M in
hexane, 18.1 mL, 30.4 mmol) was added dropwise to a stirred
solution of diisopropylamine (3.99 mL, 30.4 mmol) in 50 mL

1012 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6
Inagaki et al.
toluene was added triethylamine (3.50 mL, 25.1 mmol) fol-
lowed by diphenylphosphoryl azide (2.71 mL, 12.6 mmol)
dropwise at ambient temperature. The mixture was stirred
at ambient temperature for 1 h and then heated to reflux for
2 h. To the mixture was added 100 mL of tert-butyl alcohol,
and the mixture was heated to reflux for another 21 h. The
solvent was removed in vacuo, and the residue was purified
by silica gel column chromatography, eluting with AcOEt/
hexane ) 1:1 to yield 22 (3.30 g, 73%) as a colorless oil.
Recrystallization from n-hexane/CH2Cl2 gave colorless prisms,
m), 1.19 (3H, t, J ) 7.2 Hz), 1.35 (3H, d, J ) 6.6 Hz), 1.36-
1.42 (1H, m), 1.95-2.02 (2H, m), 2.31-2.37 (1H, m), 2.60-
2.68 (2H, m), 2.80-2.86 (1H, m), 3.16 (1H, q, J ) 6.6 Hz), 4.06
(2H, q, J ) 7.1 Hz), 7.19-7.32 (5H, m). High-resolution MS
(EI) calcd for C18H25NO2: 287.1885. Found: 287.1848.
Eth yl 1-{(3S,4R)-4-F lu or o-1-[(S)-1-p h en yleth yl]p yr r o-
lid in -3-yl}cyclop r op a n eca r boxyla te (24b). To a solution of
23b (4.40 g, 13.1 mmol) in 150 mL of EtOH was added Raney
nickel catalyst (W-6, 13 mL), and then the mixture was stirred
for 1 h at ambient temperature. With the purification proce-
dures as described for 24a , the title compound (3.79 g, 95%)
was prepared as a colorless oil. 1H NMR (CDCl3): δ 0.66-
0.71 (1H, m), 0.83-0.88 (1H, m), 1.19 (3H, t, J ) 7.3 Hz), 1.28-
1.44 (2H, m), 1.37 (3H, d, J ) 6.8 Hz), 2.02 (1H, dm, J ) 29.3
Hz), 2.10 (1H, q, J ) 9.3 Hz), 2.67 (1H, ddd, J ) 5.4, 11.2,
33.2 Hz), 2.80 (1H, t, J ) 7.8 Hz), 3.17 (1H, q, J ) 6.8 Hz),
3.33 (1H, dd, J ) 11.2, 23.0 Hz), 4.06 (2H, q, J ) 7.3 Hz), 5.16
(1H, dd, J ) 3.4, 56.7 Hz), 7.21-7.34 (5H, m). High-resolution
1
and the crystals were analyzed by X-ray crystallography. H
NMR (CDCl3): δ 0.58-0.66 (1H, m), 0.70-0.82 (2H, m), 0.88-
0.96 (1H, m), 1.31 (9H, s), 1.54 (3H, d, J ) 7.3 Hz), 2.36-2.52
(1H, m), 2.86 (1H, t, J ) 8.3 Hz), 3.32 (1H, t, J ) 8.3 Hz), 4.99
(1H, dd, J ) 6.4, 52.7 Hz), 4.99 (1H, s), 5.46 (1H, q, J ) 7.3
Hz), 7.27-7.42 (5H, m). High-resolution MS (FAB) calcd for
C
20H27FN2O3 + Na: 385.1903. Found: 385.1914. [R]D -167.4°
(c 0.608, CHCl3).
MS (ESI) calcd for
306.3962.
C18H24FNO2 + H: 306.3951. Found:
Eth yl 1-{(3S)-1-[(S)-1-P h en yleth yl]-5-th ioxop yr r olid in -
3-yl}cyclop r op a n eca r boxyla te (23a ). To a solution of 17a
(4.05 g, 13.4 mmol) in 100 mL of anhydrous benzene was added
Lawesson’s reagent (6.53 g, 16.1 mmol), and then the mixture
was heated to reflux for 3 h under nitrogen atmosphere. The
solvent was removed in vacuo, and the residue was purified
by silica gel column chromatography, eluting with AcOEt/
hexane ) 1:3 to yield 23a (4.18 g, 98%) as a colorless
amorphous product. 1H NMR (CDCl3): δ 0.63 (2H, m), 1.11
(2H, m), 1.14 (3H, t, J ) 7.1 Hz), 1.59 (3H, d, J ) 7.1 Hz),
2.65-2.72 (1H, m), 2.79 (1H, m), 3.00-3.13 (2H, m), 3.77 (1H,
dd, J ) 8.5, 11.5 Hz), 4.02 (2H, m), 6.40 (1H, q, J ) 7.1 Hz),
Eth yl 1-{(3S,4S)-4-F lu or o-1-[(S)-1-p h en yleth yl]p yr r o-
lid in -3-yl}cyclop r op a n eca r boxyla te (24c). Following the
procedures as described for 24b, the title compound was
prepared in 86% yield from 23c as a colorless oil. 1H NMR
(CDCl3): δ 0.54-0.60 (1H, m), 0.95-1.08 (2H, m), 1.22 (3H, t,
J ) 7.3 Hz), 1.25-1.32 (1H, m), 1.35 (3H, d, J ) 6.4 Hz), 1.99
(1H, t, J ) 9.3 Hz), 2.42 (1H, t, J ) 8.3 Hz), 2.63 (1H, ddd,
J ) 2.0, 11.7, 33.2 Hz), 2.99 (1H, dm, J ) 28.3 Hz), 3.25-3.37
(2H, m), 4.03-4.16 (2H, m), 5.33 (1H, dm, J ) 55.7 Hz), 7.21-
7.36 (5H, m). High-resolution MS (EI) calcd for C18H24FNO2:
305.1791. Found: 305.1760.
7.30-7.36 (5H, m). High-resolution MS (EI) calcd for C18H23
NO2S: 317.1450. Found: 317.1446.
-
Eth yl 1-{(3S)-4,4-Diflu or o-1-[(S)-1-p h en yleth yl]p yr r o-
lid in -3-yl}cyclop r op a n eca r boxyla te (24d ). With the pro-
cedures as described for 24b, the title compound was prepared
Eth yl 1-{(3S,4R)-4-F lu or o-1-[(S)-1-p h en yleth yl]-5-th i-
oxop yr r olid in -3-yl}cyclop r op a n eca r boxyla te (23b). Fol-
lowing the procedures as described for 23a , the title compound
was prepared in 89% yield from 19 as a pale-yellow oil. 1H
NMR (CDCl3): δ 0.75-0.82 (1H, m), 0.88-0.93 (1H, m), 1.11
(3H, t, J ) 7.3 Hz), 1.25-1.34 (2H, m), 1.64 (3H, d, J ) 7.3
Hz), 2.28 (1H, dq, J ) 8.3, 26.9 Hz), 3.12-3.18 (1H, m), 3.72
(1H, dd, J ) 9.3, 11.2 Hz), 3.92-4.08 (2H, m), 5.22 (1H, dd,
J ) 7.8, 53.2 Hz), 6.33 (1H, q, J ) 7.3 Hz), 7.28-7.38 (5H, m).
High-resolution MS (ESI) calcd for C18H22FNO2S + H: 335.4442.
Found: 335.4459.
1
in 96% yield from 23d as a colorless oil. H NMR (CDCl3): δ
0.67-0.89 (2H, m), 1.19 (3H, t, J ) 7.3 Hz), 1.27-1.46 (2H,
m), 1.38 (3H, d, J ) 7.3 Hz), 2.49-2.62 (2H, m), 2.69-2.97
(2H, m), 3.20 (1H, q, J ) 7.3 Hz), 3.48-3.52 (1H, m), 3.94-
4.09 (2H, m), 7.28-7.34 (5H, m). High-resolution MS (ESI)
calcd for C18H23F2NO2 + H: 324.3855. Found: 324.3829.
Eth yl 1-[(3S)-1-Ben zyloxyca r bon ylp yr r olid in -3-yl]cy-
clop r op a n eca r boxyla te (25a ). Under
a nitrogen atmo-
sphere, benzyl chloroformate (2.72 mL, 19.0 mmol) was added
to a solution of 24a (2.74 g, 9.52 mmol) in 50 mL of anhydrous
CH2Cl2 at ambient temperature, and then the mixture was
stirred at 40 °C for 15 h. After the solvent was removed in
vacuo, the residue was purified by silica gel column chroma-
tography, eluting with AcOEt/hexane ) 1:2 to yield 25a (2.68
Eth yl 1-{(3S,4S)-4-F lu or o-1-[(S)-1-p h en yleth yl]-5-th i-
oxop yr r olid in -3-yl}cyclop r op a n eca r boxyla te (23c). Fol-
lowing the procedures as described for 23a , the title compound
was prepared in 90% yield from 20 as a pale-yellow oil. 1H
NMR (CDCl3): δ 0.59-0.66 (1H, m), 0.86-0.92 (1H, m), 1.08-
1.15 (1H, m), 1.20 (3H, t, J ) 7.3 Hz), 1.24-1.31 (1H, m), 1.60
(3H, d, J ) 7.3 Hz), 2.85 (1H, dd, J ) 9.3, 11.2 Hz), 3.16 (1H,
qd, J ) 8.3, 30.3 Hz), 3.50 (1H, dd, J ) 9.3, 11.2 Hz), 4.04-
4.15 (2H, m), 5.32 (1H, dd, J ) 5.4, 52.7 Hz), 6.28-6.34 (1H,
m), 7.30-7.41 (5H, m). High-resolution MS (EI) calcd for
1
g, 89%) as a colorless oil. H NMR (CDCl3): δ 0.74-0.80 (2H,
m), 1.18-1.25 (5H, m), 1.41-1.56 (1H, m), 1.84-1.97 (1H, m),
2.72-2.83 (1H, m), 2.93 (1H, dd, J ) 10.2, 18.3 Hz), 3.30 (1H,
dt, J ) 6.8, 10.7 Hz), 3.53-3.62 (1H, m), 3.66-3.70 (1H, m),
4.08-4.13 (2H, m), 5.12 (2H, m), 7.28-7.36 (5H, m). High-
resolution MS (FAB) calcd for C18H23NO4 + H: 318.1705.
Found: 318.1694.
C
18H22FNO2S: 335.1355. Found: 335.1354.
Eth yl 1-{(3S)-4,4-Diflu or o-1-[(S)-1-p h en yleth yl]-5-th i-
oxop yr r olid in -3-yl}cyclop r op a n eca r boxyla te (23d ). With
the procedures as described for 23a , the title compound was
prepared in 76% yield from 21 as a pale-yellow oil. H NMR
Eth yl 1-[(3S,4R)-1-Ben zyloxyca r bon yl-4-flu or op yr r o-
lid in -3-yl]cyclop r op a n eca r boxyla te (25b). With the pro-
cedures as described for 25a , the title compound was prepared
1
1
(CDCl3): δ 0.85-0.95 (2H, m), 1.10 (3H, t, J ) 6.8 Hz), 1.24-
1.32 (2H, m), 1.64 (3H, d, J ) 7.3 Hz), 2.69-2.81 (1H, m), 3.20
(1H, ddd, J ) 2.9, 6.8, 11.7 Hz), 3.73 (1H, td, J ) 2.5, 10.3
Hz), 3.84-3.92 (1H, m), 4.02-4.11 (1H, m), 6.31 (1H, q, J )
7.3 Hz), 7.32-7.38 (5H, m). High-resolution MS (ESI) calcd
for C18H21F2NO2S + H: 354.4346. Found: 354.4320.
E t h yl 1-{(3S)-1-[(S)-1-P h en ylet h yl]p yr r olid in -3-yl}-
cyclop r op a n eca r boxyla te (24a ). To a solution of 23a (3.75
g, 11.8 mmol) in 40 mL of EtOH was added Raney nickel
catalyst (W-6, 20 mL), and then the mixture was heated to
reflux for 6 h. After the mixture was cooled to ambient
temperature, the catalyst was removed by filtration through
Celite and the filtrate was concentrated in vacuo. The residue
was purified by silica gel column chromatography, eluting with
MeOH/CH2Cl2 ) 1:20 to yield 24a (3.07 g, 91%) as a colorless
oil. 1H NMR (CDCl3): δ 0.68-0.76 (2H, m), 1.06-1.12 (2H,
in 89% yield from 24b as a colorless oil. H NMR (CDCl3): δ
0.71-0.78 (1H, m), 0.90-0.95 (1H, m), 1.23 (3H, t, J ) 6.8
Hz), 1.19-1.25 (1H, m), 1.28-1.32 (1H, m), 2.48 (1H, dm, J )
28.3 Hz), 3.27 (1H, t, J ) 10.3 Hz), 3.67 (1H, dd, J ) 13.2,
23.9 Hz), 3.80-3.92 (2H, m), 4.11 (2H, q, J ) 6.8 Hz), 5.14
(2H, s), 5.17 (1H, br d, J ) 55.2 Hz), 7.29-7.35 (5H, m). High-
resolution MS (ESI) calcd for C18H22FNO4 + H: 336.3780.
Found: 336.3761.
Eth yl 1-[(3S,4S)-1-Ben zyloxyca r bon yl-4-flu or op yr r o-
lid in -3-yl]cyclop r op a n eca r boxyla te (25c). With the pro-
cedures as described for 25a , the title compound was prepared
1
in 89% yield from 24c as a colorless oil. H NMR (CDCl3): δ
0.71-0.78 (1H, m), 1.11-1.23 (2H, m), 1.24 (3H, t, J ) 6.8
Hz), 1.29-1.37 (1H, m), 2.93-3.00 (1H, m), 3.10 (1H, dm, J )
34.7 Hz), 3.54-3.84 (3H, m), 4.09-4.18 (2H, m), 5.14 (2H, s),
5.34 (1H, ddm, J ) 16.6, 53.7 Hz), 7.29-7.38 (5H, m). High-

SARs of Antibacterials
J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6 1013
resolution MS (FAB) calcd for C18H22FNO4 + H: 336.1611.
Found: 336.1616.
dd, J ) 2.9, 11.2 Hz), 3.59-3.76 (3H, m), 4.91 (1H, br s), 5.14
(2H, s), 5.40 (1H, br d, J ) 52.7 Hz), 7.28-7.33 (5H, m). High-
resolution MS (ESI) calcd for C20H27FN2O4 + H: 379.4458.
Found: 379.4439. [R]D +12.9° (c 0.622, MeOH).
(3S,4R)-1-Ben zyloxyca r bon yl-4-[1-(ter t-bu toxyca r bon -
ylam in o)cyclopr opan -1-yl]-3-flu or opyr r olidin e (27c). With
the procedures as described for 27a , the title compound was
prepared in 81% yield from 26c as a colorless oil. 1H NMR
(CDCl3): δ 0.65-0.74 (1H, m), 0.77-0.84 (1H, m), 0.85-1.00
(2H, m), 1.42 (9H, s), 2.21 (1H, dm, J ) 36.1 Hz), 3.08-3.24
(1H, m), 3.48-3.84 (3H, m), 5.02 (1H, br s), 5.13 (2H, s), 5.15
(1H, br d, J ) 53.7 Hz), 7.28-7.38 (5H, m). High-resolution
MS (FAB) calcd for C20H27FN2O4 + H: 379.2033. Found:
379.2000. [R]D -9.3° (c 0.381, CHCl3).
(4R)-1-Ben zyloxyca r b on yl-4-[1-(ter t-b u t oxyca r b on yl-
a m in o)cyclop r op a n -1-yl]-3,3-d iflu or op yr r olid in e (27d ).
With the procedures as described for 27a , the title compound
was prepared in 60% yield from 26d as a colorless oil. 1H NMR
(CDCl3): δ 0.83-0.92 (2H, m), 1.40 (9H, s), 1.34-1.55 (2H,
m), 2.38-2.51 (1H, m), 3.47 (1H, t, J ) 9.3 Hz), 3.67-3.84 (3H,
m), 4.99 (1H, br s), 5.13 (2H, s), 7.29-7.35 (5H, m). High-
resolution MS (FAB) calcd for C20H26F2N2O4 + H: 397.4362.
Found: 397.4388. [R]D +10.0° (c 0.410, MeOH).
5-Am in o-7-[(3R)-3-(1-am in ocyclopr opan -1-yl)pyr r olidin -
1-yl]-6-flu or o-1-[(1R,2S)-2-flu or ocyclop r op a n -1-yl]-1,4-d i-
h yd r o-8-m eth yl-4-oxoqu in olin -3-ca r boxylic Acid (1). To
a solution of 27a (649 mg, 1.80 mmol) in 20 mL of MeOH was
added 5% Pd/C (200 mg, containing 55.6% water), and the
mixture was heated by a lamp with vigorous shaking under
hydrogen (atmospheric pressure) for 2 h. The catalyst was
filtered off, and the filtrate was concentrated in vacuo. The
residue was mixed with 9 (312 mg, 1.00 mmol), 2 mL of
triethylamine, and 20 mL of DMSO, and the mixture was
heated at 150 °C for 18 h under nitrogen atmosphere. The
solvent was removed in vacuo, the residue was dissolved with
CHCl3, and the solution was washed with 10% aqueous citric
acid and brine. The resultant solution was dried over anhy-
drous Na2SO4, filtered, and concentrated in vacuo. To the
residue was added 10 mL of concentrated aqueous HCl at 0
°C, and the mixture was stirred for 1 h at ambient tempera-
ture. The solution was washed with CH2Cl2 and made alkaline
with saturated aqueous NaOH at 0 °C, and then the pH of
the solution was adjusted to 7.4 with concentrated aqueous
HCl and dilute aqueous HCl. The resultant solution was
extracted with chloroform (4×), and the combined organic layer
was dried over anhydrous Na2SO4, filtered, and concentrated
in vacuo. The residue was purified by semiseparable TLC,
eluting with an underlayer solution of CHCl3/MeOH/water )
7:3:1 to give the crude product. The crude product was
recrystallized from CHCl3/diisopropyl ether to yield 1 (102 mg,
24%) as a yellow powder, mp 215-216 °C. 1H NMR (0.1 N
NaOD/D2O): δ 0.55 (4H, m), 1.09-1.18 (1H, m), 1.45-1.57
(1H, m), 1.61-1.74 (1H, m), 1.95-2.05 (1H, m), 2.16-2.25 (1H,
m), 2.27 (3H, s), 3.24-3.37 (2H, m), 3.45-3.57 (1H, m), 3.68-
3.80 (1H, m), 3.89-3.98 (1H, m), 4.85-4.91, 5.02-5.07 (1H,
m), 8.26 (1H, d, J ) 2.9 Hz). [R]D -407.0° (c 0.115, 0.1 N
aqueous NaOH ). Anal. (C21H24F2N4O3‚0.5H2O) C, H, N.
5-Am in o-7-[(3R,4R)-4-(1-a m in ocyclop r op a n -1-yl)-3-flu -
or op yr r olid in -1-yl]-6-flu or o-1-[(1R,2S)-2-flu or ocyclop r o-
p a n -1-yl]-1,4-d ih yd r o-8-m eth yl-4-oxoqu in olin -3-ca r box-
ylic Acid Hyd r och lor id e (2). To a solution of 27b (758 mg,
2.00 mmol) in 80 mL of MeOH was added 5% Pd/C (800 mg,
containing 55.6% water), and the mixture was shaken vigor-
ously under 4.5 kg/cm2 of hydrogen for 7 h at ambient
temperature. The catalyst was filtered off, and the catalyst
was concentrated in vacuo. The residue was mixed with 9 (405
mg, 1.30 mmol), 3 mL of triethylamine, and 8 mL of DMSO,
and the mixture was heated at 120 °C for 4 days under
nitrogen atmosphere. The solvent was removed in vacuo, the
residue was dissolved in CHCl3, and the solution was washed
with 10% aqueous citric acid (2×) and brine. The resultant
solution was dried over anhydrous Na2SO4, filtered, and
concentrated in vacuo. To the residue was added 10 mL of
concentrated aqueous HCl at 0 °C, and the mixture was stirred
Eth yl 1-[(3S)-1-Ben zyloxyca r bon yl-4,4-d iflu or op yr r o-
lid in -3-yl]cyclop r op a n eca r boxyla te (25d ). With the pro-
cedures as described for 25a , the title compound was prepared
1
in 83% yield from 24d as a colorless oil. H NMR (CDCl3): δ
0.97-1.05 (1H, m), 1.07-1.16 (1H, m), 1.20-1.30 (1H, m), 1.22
(3H, t, J ) 7.3 Hz), 1.32-1.42 (1H, m), 2.93-3.07 (2H, m),
3.36-3.44 (1H, m), 3.77-3.84 (1H, m), 3.93 (1H, t, J ) 10.7
Hz), 4.12 (2H, dq, J ) 1.5, 7.3 Hz), 5.14 (2H, s), 7.28-7.35
(5H, m). High-resolution MS (ESI) calcd for C18H21F2NO4
H: 354.3684. Found: 354.3693.
+
1-[(3S)-1-Ben zyloxyca r bon ylp yr r olid in -3-yl]cyclop r o-
p a n eca r boxylic Acid (26a ). To a solution of 25a (4.34 g, 12.9
mmol) in 50 mL of EtOH was added 1 N aqueous NaOH (50
mL, 50 mmol) at 0 °C, and then the mixture was stirred at 40
°C for 3 h. After the mixture was concentrated in vacuo, water
was added to the resultant solution and the aqueous solution
was washed with CH2Cl2 (2×). The aqueous layer was acidified
with concentrated aqueous HCl at 0 °C and extracted with
CHCl3 (2×). The combined organic layer was dried over
anhydrous Na2SO4 and concentrated in vacuo to yield 26a
(4.11 g, quantitative) as a colorless amorphous product. 1H
NMR (CDCl3): δ 0.80-0.90 (2H, m), 1.23-1.31 (2H, m), 1.43-
1.60 (1H, m), 1.85-2.00 (1H, m), 2.69-2.78 (1H, m), 2.95 (1H,
dd, J ) 10.0, 19.3 Hz), 3.30 (1H, dt, J ) 6.8, 10.6 Hz), 3.54-
3.63 (1H, m), 2.95 (1H, dd, J ) 7.9, 10.4 Hz), 5.12 (2H, s), 7.29-
7.36 (5H, m). MS (EI) m/z: 289 (M+).
1-[(3S,4R)-1-Ben zyloxyca r bon yl-4-flu or op yr r olid in -3-
yl]cyclop r op a n eca r boxylic Acid (26b). With the proce-
dures as described for 26a , the title compound was prepared
1
in 98% yield from 25b as a colorless amorphous product. H
NMR (CDCl3): δ 0.84-0.89 (1H, m), 0.99-1.07 (1H, m), 1.32-
1.42 (2H, m), 2.37-2.56 (1H, m), 3.26-3.31 (1H, m),
3.58-3.67 (1H, m), 3.82-3.88 (2H, m), 5.13 (2H, s), 5.20 (1H,
br d, J ) 55.0 Hz), 7.30-7.34 (5H, m). MS (ESI) m/z: 308
(M + H+).
1-[(3S,4S)-1-Ben zyloxyca r bon yl-4-flu or op yr r olid in -3-
yl]cyclop r op a n eca r boxylic Acid (26c). With the procedures
as described for 26a , the title compound was prepared in 92%
yield from 25c as a colorless amorphous product. 1H NMR
(CDCl3): δ 0.79-0.89 (1H, m), 1.18-1.35 (2H, m), 1.37-1.47
(1H, m), 2.90-3.18 (2H, m), 3.50-3.84 (3H, m), 5.13 (2H, s),
5.31 (1H, ddm, J ) 15.1, 53.2 Hz), 7.26-7.42 (5H, m). MS
(FAB) m/z: 308 (M + H+).
1-[(3S)-1-Ben zyloxyca r bon yl-4,4-d iflu or op yr r olid in -3-
yl]cyclop r op a n eca r boxylic Acid (26d ). With the proce-
dures as described for 26a , the title compound was prepared
1
in 93% yield from 25d as a colorless oil. H NMR (CDCl3): δ
1.08-1.14 (1H, m), 1.19-1.28 (1H, m), 1.37-1.42 (1H, m),
1.44-1.49 (1H, m), 2.93-3.09 (1H, m), 3.37-3.46 (1H, m),
3.76-3.85 (2H, m), 3.92-4.00 (1H, m), 5.14 (2H, s), 7.29-7.34
(5H, m). MS (ESI) m/z: 348 (M + Na+), 326 (M + H+).
(3R)-1-Ben zyloxyca r b on yl-3-[1-(ter t-b u t oxyca r b on yl-
a m in o)cyclop r op a n -1-yl]p yr r olid in e (27a ). To a solution
of 26a (289 mg, 1.00 mmol) in 10 mL of tert-butyl alcohol was
added triethylamine (0.24 mL, 1.60 mmol) and diphenylphos-
phoryl azide (0.28 mL, 1.30 mmol), and the mixture was stirred
at ambient temperature for 2 h and then heated to reflux for
18 h. The solvent was removed in vacuo, and the residue was
purified by silica gel column chromatography, eluting with
AcOEt/hexane ) 1:4 to yield 27a (263 mg, 73%) as a colorless
1
amorphous product. H NMR (CDCl3): δ 0.65-0.85 (4H, m),
1.41 (9H, m), 1.57-1.72 (1H, m), 1.88-1.97 (1H, m), 2.17-
2.32 (1H, m), 3.07-3.13 (1H, m), 3.26-3.33 (1H, m), 3.51-
3.65 (2H, m), 4.88 (1H, br d, J ) 10.5 Hz), 5.12 (2H, m), 7.25-
7.36 (5H, m). High-resolution MS (FAB) calcd for C20H28N2O4
+ H: 361.2127. Found: 361.2126. [R]D +8.8° (c 0.345, CHCl3).
(3R,4R)-1-Ben zyloxyca r bon yl-4-[1-(ter t-bu toxyca r bon -
ylam in o)cyclopr opan -1-yl]-3-flu or opyr r olidin e (27b). With
the procedures as described for 27a , the title compound was
prepared in 65% yield from 26b as a colorless oil. 1H NMR
(CDCl3): δ 0.64-0.70 (1H, m), 0.79-0.83 (1H, m), 0.86-1.09
(2H, m), 1.39 (9H, s), 2.21 (1H, dm, J ) 21.5 Hz), 3.44 (1H,

1014 J ournal of Medicinal Chemistry, 2003, Vol. 46, No. 6
Inagaki et al.
for 15 min at ambient temperature. After 10 mL of water was
added to the solution, the solution was washed with CH2Cl2
(4×) and made alkaline with saturated aqueous NaOH at 0
°C. Then the pH of the solution was adjusted to 7.4 with
concentrated aqueous HCl and dilute aqueous HCl, and the
resultant solution was extracted with CHCl3 (4×). The com-
bined extract was dried over anhydrous Na2SO4, filtered, and
concentrated in vacuo. The residue was purified by semisepa-
rable TLC, eluting with an underlayer solution of CHCl3/
MeOH/water ) 7:3:1. To a solution of the crude product in 20
mL of EtOH was added 1.5 mL of 1 N aqueous HCl dropwise
at 0 °C. The solution was stirred for 5 min at 0 °C and
concentrated in vacuo. The residue was recrystallized from
EtOH/diisopropyl ether to yield 2 (142 mg, 22%) as a yellow
powder, mp 220-225 °C. 1H NMR (0.1 N NaOD/D2O): δ 0.58-
0.68 (4H, m), 1.11-1.25 (1H, m), 1.52-1.59 (1H, m), 2.39-
2.49 (1H, m), 2.41 (3H, s), 3.39 (1H, t, J ) 9.3 Hz), 3.58-3.67
(1H, m), 3.71-3.83 (2H, m), 3.88-3.99 (1H, m), 4.96 (1H, dm,
J ) 65.9 Hz), 5.49 (1H, br d, J ) 54.7 Hz), 8.27 (1H, d, J ) 3.4
Hz). [R]D -342.0° (c 0.444, H2O). Anal. (C21H23F3N4O3‚HCl‚
H2O) C, H, N.
Su p p or tin g In for m a tion Ava ila ble: Crystal structures
and crystallographic details for 18 and 22. This material is
available free of charge via the Internet at http://pubs.acs.org.
Refer en ces
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5-Am in o-7-[(3S,4R)-4-(1-a m in ocyclop r op a n -1-yl)-3-flu -
or op yr r olid in -1-yl]-6-flu or o-1-[(1R,2S)-2-flu or ocyclop r o-
p a n -1-yl]-1,4-d ih yd r o-8-m eth yl-4-oxoqu in olin -3-ca r box-
ylic Acid (3 ) DQ-113). With the procedures as described
for 1, the title compound was prepared in 12% yield from 9
1
and 27c as a yellow powder, mp 199-201 °C. H NMR (0.1 N
NaOD/D2O): δ 0.55-0.71 (4H, m), 1.10-1.21 (1H, m), 1.46-
1.58 (1H, m), 2.30 (3H, s), 2.21-2.35 (1H, m), 3.32 (1H, t, J )
8.8 Hz), 3.49 (1H, dd, J ) 12.2, 25.9 Hz), 3.85-3.97 (2H, m),
4.11 (1H, ddm, J ) 12.5, 40.8 Hz), 4.97 (1H, dm, J ) 70.3 Hz),
5.49 (1H, br d, J ) 55.2 Hz), 8.27 (1H, d, J ) 3.4 Hz). [R]D
-488.3° (c 0.985, 0.1 N aqueous NaOH ). Anal. (C21H23F3N4O3)
C, H, N, F.
5-Am in o-7-[(4R)-4-(1-a m in ocyclop r op a n -1-yl)-3,3-d iflu -
or op yr r olid in -1-yl]-6-flu or o-1-[(1R,2S)-2-flu or ocyclop r o-
p a n -1-yl]-1,4-d ih yd r o-8-m eth yl-4-oxoqu in olin -3-ca r box-
ylic Acid Hydr och lor ide (4). With the procedures as described
for 2, the title compound was prepared in 20% yield from 9
1
and 27d as a yellow powder, mp 211-215 °C. H NMR (0.1 N
NaOD/D2O): δ 0.59-0.71 (4H, m), 1.08-1.20 (1H, m), 1.48-
1.57 (1H, m), 2.25-2.33 (1H, m), 2.30 (3H, s), 3.37-3.54 (1H,
m), 3.88 (1H, t, J ) 9.3 Hz), 3.90-3.95 (2H, m), 3.97-4.04 (1H,
m), 4.96 (1H, dm, J ) 65.9 Hz), 8.25 (1H, d, J ) 2.9 Hz). [R]D
-410.0° (c 0.220, H2O). Anal. (C21H22F4N4O3‚HCl‚1.5H2O) C,
H, N.
5-Am in o-7-[(3S)-3-(a m in om eth yl)p yr r olid in -1-yl]-6-flu -
or o-1-[(1R,2S)-2-flu or ocyclop r op a n -1-yl]-1,4-d ih yd r o-8-
m eth yl-4-oxoqu in olin -3-ca r boxylic Acid (30). With the
procedures as described for 1, the title compound was prepared
in 51% yield from 9 and 28 as a yellow powder, mp 159-160
1
°C. H NMR (0.1 N NaOD/D2O): δ 1.04-1.15 (1H, m), 1.44-
1.59 (2H, m), 2.08-2.12 (1H, m), 2.23-2.34 (4H, m), 2.69 (2H,
d, J ) 6.8 Hz), 3.25-3.34 (3H, m), 3.65-3.71 (1H, m), 3.88-
3.93 (1H, m), 4.85-5.10 (1H, m), 8.27 (1H, s). [R]D -334.4° (c
0.340, 0.1 N aqueous NaOH ). Anal. (C19H22F2N4O3‚0.75H2O)
C, H, N.
5-Am in o-7-[(3R,1′S)-3-(1-a m in oeth yl)p yr r olid in -1-yl]-6-
flu or o-1-[(1R,2S)-2-flu or ocyclop r op a n -1-yl]-1,4-d ih yd r o-
8-m eth yl-4-oxoqu in olin -3-ca r boxylic Acid (31). With the
procedures as described for 1, the title compound was prepared
in 29% yield from 9 and 29 as a yellow powder, mp 225-226
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°C. H NMR (0.1 N NaOD/D2O): δ 1.11-1.19 (4H, m), 1.48-
1.59 (2H, m), 2.09-2.13 (2H, m), 2.29 (3H, s), 2.80-2.88 (1H,
m), 3.25-3.34 (1H, m), 3.37-3.46 (1H, m), 3.47-3.58 (1H, m),
3.73-3.82 (1H, m), 3.89-3.99 (1H, m), 4.85-5.10, (1H, m), 8.26
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Ack n ow led gm en t. We thank the New Product
Research Laboratory I for the biological tests. We also
thank Mr. Makoto Suzuki for the X-ray crystal analyses.

SARs of Antibacterials
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