BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a novel quinolone carboxylic acid derivatives of the following structural formula(I) and pharmaceutically acceptable salts thereof. These compounds also have a potent activity against both Gram- positive bacteria and Gram-negative bacteria :

Wherein,

R ¹ is hydrogen or .alkyl group having one to six carbon atoms, R ² is alkyl group having one to four carbon atoms, haloalkyl group having one to four carbon atoms, cycloalkyl group having three to six carbon atoms, alkenyl group having two to four carbon atoms, or phenyl group which is optionally mono or disubstituted by fluorine atoms, X is hydrogen, amino, or halogen, Y is hydrogen or halogen,

Zis

( wherein

I is 1 or 2, m is 0, 1, or 2, and n is 0 or 1, R ³ is hydrogen, alkyl group having one to four carbon atoms, haloalkylgroup

having one to three carbon atoms, acyl group, cycloalkyl group having three to six carbon atoms, aryl, or heteroaryl group).

In genera, the antioacterial activity of quinolone compounds depends

5 greatly upon the kinds of substituent groups at the 7 position. Quinolone antibacterial compounds are known with a 7-thiomorpholine substituent group having antibacterial properties(J. Med. Chem., V. 29, 394(1986)). But, there is no report on clinical use thereof yet

ι o DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a novel quinolone carboxylic acid derivatives having four, five, or six membered cyclic amines containing thio or thiomethyl group at the C-7 position. These compounds show a very excellent 15 activity against Gram-positive bacteria including S. aureus. as well as against Gram- negative bacteria and a low toxicity.

Therefore, the purpose of the present invention is to provide a novel quinolone carboxylic acid derivatives and pharmaceutically acceptable salts thereof having excellent properties, for example, potent antibacterial activities against 0 Gram-positive bacteria including S. aureus as well as against Gram-negative bacteria and high safety. Another the purpose of the present invention is to provide a process for producing a novel quinolone carboxylic acid derivatives and pharmaceutically acceptable salts thereof.

Detailed description of the present invention is as follows. The present 5 invention relates to a novel quinolone carboxylic acid derivatives of the above described structure formula(I).

The preferred examples of the group represented by Z in the above described structural formula(I) are as follows : 3-mercaptopyrrolidinyl,

3- methylthiopyrrolidinyl, 3-ethylthiopyrrolidinyl, 3-propylthiopyrrolidinyl, 3-isopropylthiopyrrolidinyl,

3-mercaptomethylpyrrolidinyl, 3-methylthiomethylpyrrolidinyl, 3-ethylthiomethylpyrrolidinyl, 3-propylthiomethylpyrrolidinyl, 3-isopropylthiomethylpyrrolidinyl,

3-mercaptoazetidinyl, 3-methylthioazetidinyl, 3-ethylthioazetidinyl, 3-propylthioazetidinyl, 3-isopropylthioazetidinyl,

3-mercaptomethylazetidinyl, 3-methylthiomethylazetidinyl, 3-ethylthiomethylazetidinyl, 3-propylthiomethylazetidinyl, 3-isopropylthiomethylazetidinyl,

3-mercaptopiperidinyl, 3-methythiopiperidinyl, 3-ethylthiopiperidinyl, 3-propylthiopiperidinyl, 3-isopropylthiopiperidinyl,

3-mercaptomethylpiperidinyl, 3-methylthiomethylpiperidinyl, 3-ethylthiomethylpiperidinyl, -propylthiomethylpiperidinyl,

3-isopropylthiomethylpiperid yl,

4-mercaptopiperidinyl,

4-methylthiopiperidinyl, 4-ethylthiopiperidinyl,

4-propylthiopiperidinyl,

4-isopropylthiopiperidinyl,

3-phenylthiopyrrolidinyl,

3-(2-pyridylthio)pyrrolidinyl, 3-phenylthiomethylpyrrolidinyl,

3-(2-pyridylthiomethyl)pyrrolidinyl,

3-phenylthioazetidinyl,

3-phenylthiopiperidinyl,

4-phenylthiopiperidinyl, 3-(2-pyridylthio)azetidinyl,

3-(2-pyridylthio)piperidinyl,

4-(2-pyridylthio)piperidinyl,

3-phenylthiomethylazetidinyl,

3-phenylthiomethylpiperidinyl, 4-phenylthiomethylpiperidinyl,

3-(2-pyridylthiomethyl)azetidinyl,

3-(2-pyridylthiomethyl)piperidinyl,

4-(2-pyridylthiomethyl)piperidinyl.

Also preferred group of compounds of this invention is compounds of the above formula(I) wherein R ² is ethyl, fluoroethyl, cyclopropyl, tert-butyl, 2,4- difluorophenyl, and 4-fluorophenyl radical.

Other preferred compounds of this invention are those wherein X is hydrogen or amino, Y is hydrogen, fluorine, or chlorine, and R ¹ is hydrogen.

Representative examples of the novel compound of the structural formula(I)

accoiding to the present invention can be given as follows, but the present ir *-ntion is not limited to the examples given as follows : l-cyclopropyl-6-fluoro-7-(3-methylthiopyrrolidinyl)- l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(3-methylthiopyrrolidinyl)- l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-5,6,8-trifluoro-7-(3-methylthiopyrrolidinyl)- l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(3-ethylthiopyrrolidinyl)- l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-(2,4-difluorophenyl)-6,8-difluoro-7-(3-methylthiopyrrolidi nyl)- l,4-dihydro-4- oxo-3-quinolinecarboxylic acid, l-(2,4-difluorophenyl)-5,6,8-trifluoro-7-(3-methylthiopyrrol idinyl)-l,4-dihydro-4- oxo-3-quinolinecarboxylic acid, l-(2,4-difluorophenyl)-6-fluoro-7-(3-methylthiopyrrolidinyl) -l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-6-fluoro-7-(3-methylthiomethylpyrrolidinyl)- 1,4-dihydr 0-4-0X0-3- quinolinecarboxyhc acid, 1 -cyclopropyl -6,8-difl uoro-7- (3-m ethylthiomethylpyrrolidinyl)- 1 ,4-di hydro-4-oxo-

3-quinolinecarboxylic acid, l-cyclopropyl-5,6,8-trifluoro-7-(3-methylthiomethylpyrrolidi nyl)- l,4-dihydro-4- oxo-3-quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(3-ethylthiomethylpyrrolidinyl) -l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-5,6,8-trifluoro-7-(3-ethylthiomethylpyrrolidin yl)-l,4-dihydro-4- ..'- _i o-

3-quinolinecarboxylic acid, l-cyclopropyl-6-fluoro-8-chloro-7-(3-methylthiomethylpyrroli dinyl)-l,4-dihydro-4- oxo-3-quinolinecarboxylic acid,

l-(2, 4- difluorophenyl)-6,8-difluoro-7 -(3-methylthiomethylpyrrolidinyl)- 1,4- dihydro-4-oxo-3-quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(4-mercaptopiperidinyl)- l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-(2,4-difluorophenyl)-5,6,8-trifluoro-7-(3-ethylthiomethylp yrrolidinyl)-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(3-methylthioazetidinyl)-l,4-di hydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-5-amino-6,8-difluoro-7-(3-methylthiomethylpyrr olidinyl)- 1,4- dihydro-4-oxo-3-quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(3-mercaptomethylpyrrolidinyl)- l,4-dihydro-4-oxo-3- quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-[3-(2-pyridylthiomethyl)pyrroli dinyl]-l,4-dihydro-4- oxo-3-quinolinecarboxylic acid, l-(2,4-difluorophenyl)-6,8-difluoro-7-[3-(2-pyridylthiomethy l)pyrrolidinyl]-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, l-cyclopropyl-6,8-difluoro-7-(3-phenylthiomethylpyrrolidinyl )-l,4-dihydro-4-oxo- 3-quinolinecarboxylic acid, l-(2,4-difluorophenyl)-6-fluoro-7-(3-phenylthiomethylpyrroli dinyl)-l,4-dihydro-4- oxo-3-quinolinec.arboxylic acid.

The compounds of the formula(I) of the present invention can be prepared by reacting a quinolone carboxylic acid of the following structural formula(II) with an amine of the following structural formula(III) in an inert solvent or a basic solvent.

( II )

wherein :

R ¹ , R ² , R ³ , X, Y, Z, / , m, and n are as defined above, W is halogen (preferably, fluorine or chlorine),

HA is an inorganic or organic acid capable of forming a salt with amines, K is O or l.

Convenient solvents for this reaction are non-reactive solvents such as tetrahydrofuran, pyridine, eth.anol, propanol, butanol, chloroform, dimethyl- sulf oxide, dimethylformamide, water, acetonitrile, dioxane, -and the like.

Solvent mixtures may also be utilized. The reaction is preferably carried out in the presence of an acid acceptor such as an alkali metal or alkaline earth metal carbonate, alkali metal or alkaline earth metal bicarbonate, or a tertiary amine such as triethylamine, 1,8-diazabicyclo [5.4.0]undec-7-ene(DBU), pyridine, and the like.

According to the present invention, the preferred solvent is acetonitrile and the preferred base is l,8-diazabicyclo[5.4.0]undec-7-ene(DBU), triethylamine, and mixture thereof.

The reaction temperature r.anges from 50 T to 190"C , preferably from 50 13 to 120"C at atmospheric pressure. The reaction is usually carried out for about

1 hour to about 48 hours.

According to another method, the compound of the formula© can be prepared by reacting a boron complex, the formula(IV), with the compound of the

above-described formula(H[) and then hydrolyzing the reaction product.

wherein,

R ² , X, Y, and W are as defined above,

R ⁵ and R ⁶ is aliphatic acyloxy group having two to six carbon atoms or aromatic acyloxy group having seven to eleven carbon atoms.

The starting compounds having structural formulaQI) are known in the article (European Patent Application No. 78362, No. 106489, No. 113091, No. 131839, No. 153580, No. 154780, No. 202763, No. 221463, No. 235762, No. 350950, and No. 360258).

The amine compound of the above-described structural formula(III) can be prepared through the following reaction sequence from the known starting materials, for example, 3-pyrrolidinol(Aldrich's reagent), 3-piperidinol(Aldrich's reagent), 4-piperidinol(Aldrich's reagent), 3-hydroxymethyl piperidine (Aldrich's reagent), 3-hydroxymethyl pyrrolidine (J. Org. Chem., V. 26, 1519(1961)), 3- azetidinol(Chem. Commun., 93(1966)), and 3-hydroxymethylazetidine(Chem. Pharm. Bull., V. 32, 4907(1984)) :

( A ) ( B ) ( C )

( D ) ( m )

wherein, R ³ is alkyl group having one to four carbon atoms, haloalkyl group having one to three carbon atoms, acyl group, cycloalkyl group having three to six carbon atoms, aryl, or heteroaryl group, R ⁴ is amine protecting group,

Q is alkylsulfonyloxy group, .arylsulfonyloxy group, or halide, HA is organic acid or inorganic acid,

K is O or l, I is 1 or 2, m is O, l, or 2, n is O or 1. Thus compound(A) may be converted to compound(B) by treatment with an appropriate amine protection reagent. For example, a known amine protection reagent, preferably, acetic anhydride, alkoxycarbonyl anhydride, acetyl halide, or alkoxycarbonyl halide may be utilized.

The hydroxyl function of the compound(B) may next be converted to an appropriate leaving group of compound(C) by treatment with convinient reagents, for example, methanesulfonyl chloride or p-toluenesulfonyl chloride in the presence

of a base(for example, triethylamine, pyridine), or thionylchloride or phosphorous trihaUde, etc.

Compound(C) may also be converted to compound (D) by treatment with 5 thioalkoxide or mercapto compound in the presence of an appropriate base (for example, sodium hydride, potassium tert-butoxide).

Finally, compound(D) may be deprotected to produce compound of the above described structural formuIa(iπ) in the state of an acid salt or a free base by various well known reagents, for example, hydrochloric acid, trifluoroacetic acid, l o methanesulfonic acid, iodotrimethylsilane, sodium hydroxide, etc.

On the other hand, pharmaceutically acceptable acid addition salts of the above-described structural formula© are formed with organic acid or inorganic acids.

Examples of suitable acids for s-alt formation are acetic acid, lactic acid, 15 succinic acid, maleic acid, tartaric acid, citric acid, gluconic acid, ascorbic acid, benzoic acid, methanesulfonic acid, cinnamic acid, fumaric acid, phosphoric acid, hydrochloric acid, hydroiodic acid, sulfuric acid, and the like.

The salts are prepared by contacting the free base form with a sufficient amount of the desired acid to produce either a mono or di, etc. salt in the 0 conventional manner.

Pharmaceutically acceptable base salts of the above-described structural formula(I) are formed with metals such as alkali and alkaline earth metals , or amines including ammonia and organic amines.

Examples of metals used as cations are sodium, potassium, magnesium, 5 calcium, and the like. Examples of suitable amines are diethanolamine, N- methylglucamine, arginine, and the like.

The compounds of the present invention can be prepared and administered in a wide variety of oral and parenteral dosage forms.

For preparing pharmaceutical compositions from the compounds described

by this invention, inert and pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, dispersable granules, capsules, cachets, suppositories, and ointments. A solid carriers can be one or more substances which may also act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders, or tablets disintegrating agents ; it can also be an encapsulating material.

Suitable solid carriers are magnesium carbonate, magnesium sterate, talc, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methyl cellulose, sodium carboxymethyl cellulose, and the like.

Liquid form preparations include solutions, suspensions and emulsions.

As an example may be mentioned water or water-prop ylene glycol solutions for parenteral injection. Such solutions are prepared so as to be acceptable to biological systems(isotonicity, pH, etc.). Liquid preparations can also be formulated in solution in aqueous polyethylene glycol solution.

The following nonlimiting examples illustrate the inventors' preferred methods for preparing the compounds of the invention.

Reference Example 1 Preparation of N-tert-butoxycarbonyl-3-hydroxymethylpyrrolidine

A mixture of 3.5g (0.035 mole) of 3-hydroxymethylpyrrolidine[J. Org. Chem., 26, 1519(1961)] in 90ml of dioxane, 40mt of IN NaOH, and 20mZ of water was cooled to CC , treated dropwise with a solution of 9g (0.041 mole) of di- tert-butyldicaibonate in 30ml of dioxane, and warmed to room temperature. The resulting solution was stirred for 12 hours and extracted with 40m of ethyl acetate over three times. The organic layer was dried over .anhydrous magnesium sulfate, filtered and evaporated under reduced pressure to afford 5.0g of the title compound as yellowish brown oil. Η NMR(ppm, CDC1 ₃ ) : 1.45(s, 9H), 1.56 ~ 2.47(m, 3H), 2.97 ~ 3.61(m, 6H).

Reference Example 2

Preparation of N-tert-butoxycarbonyl-3-hydroxypyrrolidine

In the same manner as described in Reference Example 1, except that 3- hydroxypyrrolidine was used in place of 3-hydroxymethylpyrrolidine, the title compound was prepared as yellowish brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.44(s, 9H), 1.85 ~ 1.94(m, 2H), 3.35 ~ 3.54(m, 4H),

3.74(s, 1H), 4.40(m, 1H).

Reference Example 3

Preparation of N-tert-butoxycarbonyl-3-hydroxyazetidine

In the same manner as described in Reference Example 1, except that 3- hydroxyazetidine [Chem. Commun., 93(1968)] was used in place of 3- hydroxymethylpyrrolidine, the title compound was prepared as yellowish brown oil. ¹ H NMR(ppm, CDCl ₃ ) : 1.43(s, 9H), 3.10 ~ 3.95(m, 4H), 3.95 ~ 4.40(m, 1H).

Reference Example 4

Preparation of N-tert-butoxycarbonyl-4-hydroxypiperidine

In the same manner as described in Reference Example 1, except that 4- hydroxypiperidine was used in place of 3-hydroxymethylpyrrolidine, the title compound was prepared as pale yellow oil.

ΗNMR(ppm, CDC1 ₃ ) : 1.45(s, 9H), 1.22 ~ 2.95(m, 4H), 2.35(s, 1H), 2.85 ~

3.14(m, 2H), 3.69 ~ 3.98(m, 3H).

Reference Example 5

Preparation of N-tert-butoxycarbonyl-3-[(methylsulfonyl)-oxymethyl]pyrrolid ine

A solution of 5g(0.025 mole) of N-tert-butoxycarbonyl-3-hydroxy- methylpyirolidine in 80ml of dichloromethane was treated with 4ml (0.029mole) of triethylamine and cooled to -513 to -1013.

A solution of 3.3g(0.029 mole) of methanesulfonyl chloride in 20ml of dichloromethane was added dropwise to the reaction mixture, stirred for 10 hours at room temperature, and then treated with 80ml of water. After 30 minutes, the organic layer was separated, washed with 10'? NaHCO ₃ solution, dried over

.anhydrous magnesium sulfate, filtered, and evaporated under reduced pressure to give the crude product. This was purified by column chromatography using ethyl acetate : dichloromethane (1 : 1) as an eluent to afford 5.9g of the title compound as yellowish brown oil. Η NMR(ppm, CDCl ₃ ) : 1.45(s, 9H), 1.48 ~ 2.70(m, 3H), 3.03 (s, 3H), 3.10 ~

3.57(m, 4H), 4.20(dd, 2H).

Reference Example 6

Preparation of N-tert-butoxycarbonyl-3-[(methylsulfonyl)-oxy]pyrrolidine In the same manner as described in Reference Example 5, except that N-tert- butoxycarbonyl-3-hydroxypyrrolidine was used in place of N-tert-butoxycarbonyl-

3-hydroxymethylpyrrolidine, the title compound was prepared as pale yellowish brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.46(s, 9H), 1.99 ~ 2.31(m, 2H), 3.04(s, 3H), 3.36 ~ 3.64(m, 4H), 5.17 ~ 5.30(m, 1H).

Reference Example 7

Preparation of N-tert-butoxycarbonyl-3-[(methylsulfonyl)-oxy]azetidine

In the same manner as described in Reference Example 5, except that N-tert- butoxycarbonyl-3-hydroxyazetidine was used in place of N-tert-butoxycarbonyl-3- hydroxymethylpyrrolidine, the title compound was prepared as pale yellowish brown oil.

Η NMR(ppm, CDCl ₃ ) : 1.44(s, 9H), 3.08(s, 3H), 3.30 ~ 4.15(m, 4H),

5.2 ~ 5.4(m, 1H).

Reference Example 8

Preparation of N-tert-butoxycarbonyl-4-[(methylsulfonyl)-oxy]piperidine In the same manner as described in Reference Example 5, except that N-tert- butoxycarbonyl-4-hydroxypiperidine was used in place of N-tert-butoxycarbonyl-3- hydroxymethylpyrrolidine, the title compound was prepared as pale yellowish brown oil.

ΗNMR(ppm, CDC1 ₃ ) : 1.46(s, 9H), 1.64 ~ 2.00(m, 4H), 3.02(s, 3H), 3.12 -

3.87(m, 4H), 4.79 ~ 4.97(m, 1H).

Reference Example 9

Preparation of 3-methylthiomethylpyrrolidine hydroiodide

A solution of 2.8g(0.01 mole) of N-tert-butoxycarbonyl-3-[(methylsulfbnyl) -oxymethyl] pyrrolidine and 0.74g(0.01 mole) of sodium thiomethoxide in 30mZ of anhydrous dimethylformamide was stiired for 4 hours at 8013 and cooled to room temperature. The reaction mixture was poured into 50 ml of water and extracted with 50 ml of diethyl ether over twice. The organic layer was dried over magnesium sulfate and evaporated under reduced pressure to give the crude product. This was purified by column chromatography using diethyl ether : n- hexane (4 : 1) as an eluent to afford 2.05g of N-tert-butoxycarbonyl-3- methylthiomethylpyrrolidine as yellowish oil.

Η NMR(ppm, CDCl ₃ ) : 1.45(s, 9H), 1.61 ~ 2.36(m, 3H), 2.12(s, 3H),

2.51(d, 2H), 2.81 ~ 3.82(m, 4H). A solution of 2.05g (8.64 mmole) of N-tert-butoxycarbonyl-3- methylthiomethylpyrrolidine in 20ml of chloroform was added dropwise with 1.6ml

(11.2 mmole) of iodotrimethylsilane at 513 under N ₂ .

The resulting solution was stirred at room temperature. After 2 hours, 10 ml of meth-anol was added to the reaction mixture. Then the removal of solvent under reduced pressure was afforded 2.34g of the title compound as brown oil.

Η NMR(ppm, CDCl ₃ ) : 1.52 ~ 2.46(m, 3H), 2.13(s, 3H), 2.59(d, 2H),

2.62 - 3.41 (m, 4H), 7.02(br, 2H).

5 Reference Example 10

Preparation of 3-methylthiopyrrolidine hydroiodide

In the s-ame manner as described in Reference Example 9, except that N-tert- butoxycarbonyl-3-[(methylsulfonyl)-oxy]pyrrolidine was used in place of N-tert- butoxycarbonyl-3-[(methylsulfonyl)-oxymethyl]pyrrolidine, the title compound was i o prepared as reddish brown oil.

Η NMR(ppm, CDCl ₃ ) : 1.83 ~ 2.69(m, 2H), 2.24(s, 3H), 3.0 - 3.99(m, 5H),

8.59(br, 2H).

Reference Example 11 5 Preparation of 3-methylthioazetidine hydroiodide

In the same manner as described in Reference Example 9, except that N-tert- butoxycarbonyl-3-[(methylsulfonyl)-oxy]azetidine was used in place of N-tert- butoxycarbonyl-3-[(methylsulfonyl)-oxymethyl]pyrrolidine, the title compound was prepared as yellowish brown oil. 0 Η NMR(ppm, CDC1 ₃ ) : 2.25(s, 3H), 3.30 ~4.10(m, 5H), 7.85(br, 2H)

Reference Example 12

Preparation of 3-ethylthiomethylpyrrolidine hydroiodide

In the same manner as described in Reference Example 9, except that sodium thioethoxide was used in place of sodium thiomethoxide, the title compound was prepared as yellowish brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.28(t, 3H), 1.51 ~ 2.60(m, 5H), 2.59(d, 2H),

2.63 - 3.5 l(m, 4H), 8.86(br, 2H).

Reference Example 13

Preparation of 3-ethylthiopyrrolidine hydroiodide

In the same manner as described in Reference Example 9, except that 5 sodium thioethoxide and N-tert-butoxycarbonyl-3-[(methylsulfonyl)-oxy]pyrro- lidine were used in place of sodium thiomethoxide and N-tert-butoxycarbonyl-3-

[(methylsulfonyl)-oxymethyl]pyrrolidine, the title compound was prepared as yellowish brown oil.

Η NMRφpm, CDCl ₃ ) : 1.26(t, 3H), 1.82 - 2.69(m, 4H), 2.96 - 3.87(m, 5H), ι o 8.86(br, 2H).

Reference Example 14

Preparation of N-tert-butoxycarbonyl-4-acetylthiopiperidine

A solution of lml (0.014 mole) of thioacetic acid in 10ml of anhydrous 15 dimethylformamide was added dropwise to a suspended solution of 0.6g(0.015 mole) of 60% sodium hydride in 20ml of anhydrous dimethylformamide at -513 to

-1013. After 1 hour of stirring at this temperature, the reaction mixture was treated with 3.6g(0.013 mole) of N-tert-butoxycarbonyl-4-[(methylsulfonyl- oxy]piperidine and 1.92g (0.013 mole) of sodium iodide in 20ml of anhydrous 0 dimethylformamide. The resulting solution was stirred for 12 hours at 7013 , cooled to room temperature, added 50ml of water, stirred for 30 minutes, and extracted with 50ml of dietiiyl ether over three times.

The organic layer was dried over magnesium sulfate and evaporated under reduced pressure to give the crude product This was purified by column 5 chromatography using isopropyl ether : n-hexane (1 : 1) as an eluent to afford 1.6g of the tide compound as yellowish brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.45(s, 9H), 1.49 -2.02(m, 4H), 2.31(s, 3H),

2.89 - 3.22(m, 2H), 3.49 - 3.99(m, 3H).

Reference Example 15

Preparation of 4-acetylthiopiperidine trifluoroacetate

To a mixture of l ml of anisole and 0.7g(2.7 mmole) of N-tert- butoxycarbonyl-4-acetylthiopiperidine was added 2ml of trifluoroacetic acid at 013.

The mixture was stiired for 1 hour at room temperature. To the resulting solution was added 30ml of diethyl ether .and the precipitates were filtered to give 0.64g of the tide compound as white solid, m.p. : 118 - 12013 Η NMR(ppm, CDC1 ₃ ) : 1.82 - 2.19(m, 4H), 2.32(s, 3H), 3.03 ~ 3.41(m, 4H),

3.62 - 3.67(m, 1H), 8.49(br, 2H).

Reference Example 16

Preparation of N-tert-butoxycarbonyl-3-methylcarbothiomethylpyrrolidine A solution of 0.25g(0.9 mmole) of N-tert-butoxycarbonyl-3-[(methyl- sulfonyl)-oxymethyl]pyrrolidine in 10ml of anhydrous dimethylformamide was added dropwise to a solution of 0.16g(1.4 mmole) of potassium thioacetate in 20ml of anhydrous dimethylformamide at 0 13. The mixture was stirred for 6 hours at 8013 and cooled to room temperature. The reaction mixture was poured into 30m/ of water and extracted with 20ml of diethyl ether over twice. The organic layer was dried over magnesium sulfate, filtered, and evaporated under reduced pressure to give 0.234g of the title compound as yellowish brown oil. Η NMR(ppm, CDC1 ₃ ) : 1.45(s, 9H), 1.50 - 2.64(m, 3H), 2.34(s, 3H),

2.90(d, 2H), 3.13 ~ 3.62(m, 4H).

Reference Example 17

Preparation of N-tert-butoxycarbonyl-3-mercaptomethylpyrrolidine

To a solution of 0.3g(1.16 mmole) of N-tertbutoxycarbonyl-3-methyl- carbonylthiomethylpyrrolidine in 10ml of ethanol was added 10ml of IN

NaOH. The resulting mixture was stiired for 6 hours at 6013 , cooled to room temperature, evaporated under reduced pressure, and treated 20ml of water. Then the resulting solution was extracted witii 20m/ of diethyl ether over twice. The organic layer was dried over magnesium sulfate, filtered, and evaporated under reduced pressure to afford 0.23g of the tide compound as yellowish brown oil. ΗNMR(ppm, CDCl ₃ ) : 1.46(s, 9H), 1.73 - 2.72(m, 3H), 2.70(s, 2H),

2.84 ~ 3.90(m, 4H).

Reference Example 18

Preparation of 3-mercaptomethylpyrrolidine trifluoroacetate

To a mixture of O.lg of anisole and 0.25g of N-tert-butoxycarbonyl-3- mercaptomethylpyrrolidine was added 1ml of trifluoro acetic acid at 013. The mixture was stiired for 2 hours at room temperature. The reaction mixture was evaporated under reduced pressure followed by washing with 20ml of n-hexane over twice. This was concentrated under reduced pressure to afford 0.25g of the tide compound as yellowish brown oil.

ΗNMR(ppm, CDCl ₃ ) : 1.54 ~ 2.42(m, 3H), 2.72(d, 2H), 2.92 - 3.64(m, 5H),

8.24(br, 2H).

Reference Example 19

Preparation of N-tert-butoxycarbonyl-3-(2-pyridylthiomethyl)pyrrolidine

A solution of 0.42g(3.77 mmole) of 2-mercaptopyridine in 10 m/ of anhydrous dimethyl formamide was added dropwise to a solution of 0.15g(3.75 mmole) of 60% sodium hydride in 20ml of anhydrous dimemylformamide at -513 to

013 and stirred for 1 hour at room temperature. To the resulting solution was added a solution of lg(3.58 mmole) of N-tert-butoxycarbonyl-3-[(methylsulfonyl)- oxymethyl]pyrrolidine in 10ml of dimethylform .amide. The reaction mixture was stirred for 6 hours at 8013 to 10013 , cooled to room temperature, added 80ml of

water, and extracted with 50m/ of diethyl etiier over twice. The organic layer was dried over magnesium sulfate and evaporated under reduced pressure to give the crude product. This was purified by column chromatography using isopropyl 5 ether as an eluent to afford 0.94g of die tide compound as yellowish brown oil.

¹ H NMR(ppm, CDC1 ₃ ) : 1.45(s, 9H), 1.64 - 2.70(m, 3H), 2.95(d, 2H), 3.0 -

3.70(m, 4H), 6.90 - 7.18(m, 3H), 8.43(dd, 1H).

Reference Example 20 l o Preparation of N-tert-butoxycarbonyl-3-phenylthiomethylpyrrolidine

In the same manner as described in Reference Example 19, except that thiophenol was used in place of 2-mercaptopyridine, the title compound was prepared as yellowish brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.44(s, 9H), 1.60 - 2.62(m, 3H), 2.97(d, 2H), 5 3.10 ~ 3.72(m, 4H), 7.30(s, 5H).

Reference Example 21

Preparation of 3-(2-pyridylthiomethyl)pyrrolidine trifluoroacetate

In the same manner as described in Reference Example 18, except that N- 0 tert-butoxycarbonyl-3-(2-pyridylthiomethyl)pyrrolidine was used in place of N-teit- butoxycarbonyl-3-mercaptomethylpyrrolidine, the tide compound was prepared as brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.51 - 2.62(m, 3H), 3.04(d, 2H), 3.16 - 4.01(m, 4H),

7.20 - 9.20(m, 4H), 9.12(br, 2H).

Reference Example 22

Preparation of 3-phenylthiomethylpyrrolidine trifluoroacetate

In the same manner as described in Reference Example 18, except that N- tert-butoxycarbonyl-3-phenylthiomethylpyrrolidine was used in place of N-tert-

butoxycarbonyl-3-mercaptomethylpyrrolidine, the tide compound was prepared as brown oil.

Η NMR(ppm, CDC1 ₃ ) : 1.54 - 2.70(m, 3H), 2.95(d, 2H), 3.01 - 3.70(m, 4H), 5 7.30(s, 5H), 8.77(br, 2H).

Example 1

Preparation of l-cyclopropyl-6-fluoro-7-(3 -methylthiopyrrolidinyl)- l,4-dihydro-4- oxo-3-quinolinecarboxylic acid ι o A mixture of 0.2g(0.71 mmole) of l-cyclopropyl-6-fluoro-7-chloro-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, 0.8 g (3.24 mmole) of 3-methyIthio- pyrrolidine hydroiodide, and 0.4g(3.96 mmole) of triethylamine in 6ml of dimethylsulfoxide was stiired for 6 hours at 11013 and cooled to room temperature.

The reaction mixture was diluted with 10m/ of water, adjusted at pH 7.4 with IN 15 HC1, and then allowed to stand for 1 day. The precipitated product was filtered, washed with water and methanol, and recrystallized from methanol : dichloromediane (1 : 1) to afford 0.15g of the tide compound as pale yellow solid. m.p. : 230 - 23413

Η NMR(ppm, NaOD/D ₂ O) : 0.60 - 1.00(m, 4H), 1.41 - 2.50(m, 2H), 2.10(s, 3H), 0 2.60 - 4.21(m, 6H), 6.22(d, 1H), 7.30(d, 1H),

8.09(s, 1H)

Example 2

Preparation of l-cyclopropyl-6,8-difluoro-7-(3-methylthiopyrrolidinyl)-l,4- dihydro- 5 4-oxo-3-quinolinecarboxylic acid

A mixture of 0.1g(0.35 mmole) of l-cyclopropyl-6,7,8-trifluoro-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, 0.06g(0.39 mmole) of 1,8-diazabicyclo [5.4.0]undec-7-ene, 0.04g(0.39 mmole) of triethylamine, and 0.09g(0.37 mmole) of 3-methylthiopyrrolidine hydroiodide in 6ml of acetonitrile was stirred for 2 hours at

6013 , cooled to room temperature, and stiired for 2 hours. The precipitate was filtered, washed with acetonitrile and diethyl ether, and dried to afford 0.1 lg of the tide compound as pale yellow solid. m.p. : 214 - 21813

Η NMR(ppm, CDC1 ₃ ) : 1.09 - 1.27 (m, 4H), 1.93 - 2.37(m, 2H), 2.20(s, 3H),

3.29 ~ 3.45(m, 1H), 3.71 ~ 4.68(m, 5H), 7.73(dd, 1H),

8.7 l(s, 1H), 14.78(br, 1H).

Example 3

Preparation of 1 -cycloprop yl-5,6,8 -trifluoro-7 -(3-methylthiopyrrolidinyl)- 1 ,4- dihydro-4-oxo-3-quinolinecarboxylic acid

A mixture of 0.2g(0.66 mmole) of l-cyclopropyl-5,6,7,8-tetrafluoro- l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, 0.1g(0.66 mmole) of 1,8-diazabicyclo [5.4.0]undec-7-ene, 0.07g(0.69 mmole) of triethylamine, and 0.17g(0.69 mmole) of

3-methylthiopyrrolidine hydroiodide in 6ml of acetonitrile was stirred for 3 hours at 6013 , cooled to room temperature, and stirred for 2 hours. The precipitate was filtered, washed with acetonitrile and diethyl ether, and dried to afford 0.2g of the tide compound as pale yellow solid. m.p. : 220 - 22213

Η NMR(ppm, CDC1 ₃ ) : 1.09 - 1.25(m, 4H), 1.93 ~ 2.39(m, 2H), 2.16(s, 3H),

3.39 ~ 3.47(m, 1H), 3.73 - 4.08(m, 5H), 8.67(s, 1H), 14.63(br, 1H).

Example 4

Preparation of 1 -cycloprop yl-6,8-difluoro-7-(3-ethylthiopyrrolidinyl)- 1 ,4 -dihydro- 4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 2, except that 3-ethylthio- pyrrolidine hydroiodide was used in place of 3-methylthiopyrrolidine hydroiodide,

the tide compound was prepared as pale yellow solid. Η NMR(ppm, CDCl ₃ ) : 1.16 - 1.41(m, 7H), 1.87 - 2.76(m, 4H),

3.69 - 4.72(m, 6H), 7.74(dd, 1H), 8.70(s, 1H), 14.65(br, 1H).

Example 5

Preparation of l-(2,4-difluorophenyl)-6,8-difluoro-7-(3-methylthiopyrrolidi nyl)-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid A mixture of 0.2g(0.56 mmole) of l-(2,4-difluorophenyl)-6,7,8-trifluoro- l,4-dihydro-4-oxo-3 -quinolinecarboxylic acid, 0.09g (0.56 mmole) of 1,8- diazabicyclo[5.4.0]undec-7-ene, 0.06g(0.59 mmole) of trieti ylamine, and 0.14g(0.57 mmole) of 3-methylthiopyrrolidine hydroiodide in 10m/ of acetonitrile was stirred for 3 hours at 6013 , cooled to room temperature, stiired for 2 hours, and evaporated under reduced pressure. The mixture was diluted with 20ml of water.

The precipitate was filtered and recrystallized from methanol : dichloromethane (1:1) to afford 0.18g of the tide compound as pale yellow solid, m.p. : 188 - 19213 Η NMRφpm, CDC1 ₃ ) : 1.78 ~ 2.28(m, 2H), 2.14(s, 3H), 3.29 - 3.37(m, 1H), 3.45 - 3.85(m, 4H), 7.02 - 7.79(m, 3H),

7.96(dd, 1H), 8.42(s, 1H), 14.38(br, 1H).

Example 6

Preparation of l-(2,4-difluorophenyl)-5,6,8-trifluoro-7-(3 -methylthiopyrrolidinyl> l,4-dihydro-4-oxo-3-quinolinecarboxylic acid

A mixture of 0.2g(0.54 mmole) of l-(2,4-difluororphenyl)-5,6,7,8- tetrafluoro-l,4-dihydro-4-oxo-3-quinolinecarboxylic acid, 0.09g(0.59 mmole) of l,8-diazabicyclo[5.4.0]undec-7-ene, 0.06g(0.59 mmole) of triethylamine, and 0.14g(0.57 mmole) of 3-methylthiopyrrohdine hydroiodide in 6ml of acetonitrile

was stirred for 4 hours at 6013 , cooled to room temperature, stiired for 2 hours, and evaporated under reduced pressure. The mixture was diluted with 20ml of water. The precipitate was filtered and recrystallized from methanol : dichloromethane(l : 1) to afford 0.20g of the tide compound as pale yellow solid. m.p. : 206 - 20813 Η NMR(ppm, CDC1 ₃ ) : 1.78 - 2.37(m, 2H), 2.14(s, 3H), 3.16 - 3.45(m, 1H),

3.54 - 4.00(m, 4H), 6.94 - 7.63(m, 3H),

8.36(s, 1H), 14.4 (br, 1H).

Example 7

Preparation of l-(2,4-difluorophenyl)-6-fluoro-7-(3-methylthiopyrrolidinyl) - 1,4- dihydro-4-oxo-3-quinolinecarboxylic acid

A mixture of 0.2g(0.57 mmole) of l-(2,4-difluorophenyl)-7-chloro-6-fluoro- l,4-dihydro-4-oxo-3-quinolinecarboxylic acid, 0.8g(3.24 mmole) of 3-methylthio¬ pyrrolidine hydroiodide, and 0.4g(3.96 mmole) of triethylamine in 8m/ of dimethylsulfoxide was stirred for 7 hours at 11013 and cooled to room temperature. The reaction mixture was diluted with 20ml of water, adjusted at pH 7.4 with IN HCl, and then allowed to stand for 1 day. The precipitated product was filtered, washed with water and methanol, and recrystallized from methanol : dichloromethane(l:l) to afford 0.15g of the tide compound as pale yellow solid. m.p. : 210 ~ 21213

Η NMR(ppm, CDC1 ₃ ) : 1.78 ~ 2.28(m, 2H), 2.14(s, 3H), 3.29 ~ 4.10(m, 5H),

6.95 - 7.79(m, 5H), 8.60(s, 1H), 14.64(br, 1H).

Example 8

Preparation of l-cyclopropyl-6-fluoro-7-(3-methylthiomethylpyrrolidinyl)-l, 4- dihydro-4-oxo-3-quinolinecarboxylic acid

A mixture of 0.2g(0.71 mmole) of l-cyclopropyl-7-chloro-6-fluoro-l,4-

dihydro-4-oxo-3-quinolinecarboxylic acid, 0.9g(3.5 mmole) of 3-methylthio- methylpyrrolidine hy-droiodide, and 0.4g(3.96 mmole) of triethylamine in 6ml of dimethylsulfoxide was stirred for 6 hours at 11013 and cooled to room temperature. The reaction mixture was diluted with 15ml of water, adjusted at pH 7.4 with IN HCl, and tiien allowed to stand for 1 day. The precipitated product was filtered, washed with water and methanol, and recrystallized from methanol : dichloromethane(l:l) to -afford 0.19g of the title compound as pale yellow solid, m.p. : 196 - 19813 ΗNMRφpm, CDC1 ₃ ) : 1.19 - 1.31(m, 4H), 1.50 - 2.50(m, 3H), 2.17(s, 3H),

2.67(d, 2H), 3.20 - 4.01(m, 5H), 6.84(d, 1H), 7.80(d, 1H), 8.59(s, 1H), 15.29(br, 1H).

Example 9 Preparation of l-cyclopropyl-6,8-difluoro-7-(3-memylthiomethylpyrrolidinyl) -l,4- dihydro-4-oxo-3-quinolinecarboxylic acid

A mixture of 0.1g(0.35 mmole) of l-cyclopropyl-6,7,8-trifluoro-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, 0.06g(0.39 mmole) of 1,8-diazabicyclo [5.4.0]undec-7-ene, 0.04g(0.39 mmole) of triethylamine, and 0.1g(0.39 mmole) of 3-methylthiomethylpyirolidine hydroiodide in 6ml of acetonitrile was stirred for 3 hours at 6013 , cooled to room temperature, and stirred for 2 hours. The precipitate was filtered, washed witii acetonitrile and diethyl ether, and dried to afford 0.12g of the title compound as pale yellow solid. m.p. : 166 - 16813 Η NMRφpm, CDC1 ₃ ) : 1.10 - 1.30(m, 4H), 1.54 - 2.42(m, 3H), 2.16(s, 3H),

2.62(d, 2H), 3.34 ~ 4.20(m, 5H), 7.80(dd, 1H), 8.68(s, 1H), 14.01(br, 1H)

Example 10

Preparation of l-cyclpropyl-5,6,8-trifluoro-7-(3-methylthiomethylpyrrolidin yl)-l ,4- dihydro-4-oxo-3-quinolinecarboxylic acid A mixture of 0.2g(0.66 mmole) of l-cyclopropyl-5,6,7,8-tetrafluoro- l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, 0.1g(0.66 mmole) of 1,8-diazabicyclo

[5.4.0]undec-7-ene, 0.07g(0.67 mmole) of triethylamine, and 0.18g(0.69 mmole) of

3-methyltiιiomethylpyrrolidine hydroiodide in 6ml of acetonitrile was stiired for 3 hours at 6013 , cooled to room temperature, and stirred for 3 hours. The precipitate was filtered, washed with acetonitrile and diethyl etiier, and dried to afford 0.2 lg of the tide compound as pale yellow solid. m.p. : 200 - 20413

Η NMRφpm, CDC1 ₃ ) : 1.17 - 1.27(m, 4H), 1.76 ~ 2.49(m, 3H), 2.17(s, 3H),

2.63(d, 2H), 3.54 - 4.04(m, 5H), 8.63(s, 1H), 14.31(br, 1H)

Example 11

Preparation of l-cyclopropyl-6,8-difluoro-7-(3-ethylthiomethylpyιrolidinyl )-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid In the same manner as described in Example 9, except that 3- ethylthiomethylpyrrolidine hydroiodide was used in place of 3-methylthio- methylpyrrolidine hydroiodide, the tide compound was prepared as pale yellow solid.

Η NMR(ppm, CDC1 ₃ ) : 1.12 - 1.43(m, 7H), 1.64 ~ 2.38(m, 3H), 2.42 - 2.78(m, 4H), 3.32 - 4.26(m, 5H), 7.82(dd, 1H),

8.67(s, 1H), 14.26(br, 1H)

Example 12

Preparation of 1 -cyclopropyl-5,6,8-trifluoro-7-(3-ethylthiomethylpyrrolidiny l)- 1 ,4-

d ydro-4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 10, except that 3-ethylthio- methylpyrrolidine hydroiodide was used in place of 3-methylthiomethylpyrrolidine 5 hydroiodide, the tide compound was prepared as pale yellow solid.

Η NMRφpm, CDC1 ₃ ) : 1.17 - 1.46(m, 7H), 1.58 - 2.42(m, 3H),

2.41 - 2.80(m, 4H), 3.26 - 4.24(m, 5H), 8.63(s, 1H), 14.42(br, 1H)

ι o Example 13

Preparation of l-cyclopropyl-6-fluoro-8-chloro-7-(3-methylthiomethylpyrroli dinyl)-

1 ,4-dihydro-4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 9, except that 1-cyclopropyl-

6,7-difluoro-8-chloro-l,4-dihydro-4-oxo-3-quinolinecarbox ylic acid was used in 15 place of l-cyclopropyl-6,7,8-trifluoro-l,4-dihydro-4-oxo-3-quinolinec ai )Oxylic acid, the title compound was prepared as pale yellow solid.

Η NMRφpm, CDC1 ₃ ) : 1.12 - 1.32(m, 4H), 1.52 - 2.43 (m, 3H), 2.16(s, 3H),

2.61(d, 2H), 3.32 ~ 4.16(m, 5H), 7.84(dd, 1H), 8.64(s, 1H), 14.38(br, 1H) 0

Example 14

Preparation of l-(2,4-difluorophenyl)-6,8-difluoro-7-(3-methylthiomethylpyr roli- dinyl)- 1 ,4-dihydro-4-oxo-3-quinolinec-arboxylic acid

A mixture of 0.2g(0.56 mmole) of l-(2,4-difluorophenyl)-6,7,8-trifiuoro- 5 l,4-dihydro-4-oxo-3-quinolinecarboxylic acid, 0.09g(0.59 mmole) of 1,8- diazabicyclo[5.4.0]undec-7-ene, 0.06g(0.59 mmole) of triethylamine, and

0.15g(0.58 mmole) of 3-methylthiomethylpyrrolidine hydroiodide in 8m/ of acetonitrile was stirred for 4 hours at 6013 , cooled to room temperature, stiired for 2 hours, and evaporated under reduced pressure.

The mixture was diluted with 20ml of water. The precipitate was filtered and recrystallized from methanol : dichloromethane(l:l) to .afford 0.2g of die title compound as pale yellow solid. m.p. : 178 - 18213

Η NMR(ppm, CDC1 ₃ ) : 1.47 - 2.34(m, 3H), 2.14(s, 3H), 2.60(d, 2H),

3.60 - 3.78(m, 4H), 6.95 - 7.52(m, 3H), 7.75(dd, 1H), 8.41(s, 1H), 14.54(br, 1H)

Example 15

.Preparation of l-(2,4-difluorophenyl)-5,6,8-trifiuoro-7-(3-memylthiomemylpy nOli- dinyl)- 1 ,4-dihydro-4-oxo-3-quinolinec.arboxylic acid

A mixture of 0.2g(0.54 mmole) of l -(2,4-difluorophenyl)-5,6,7,8- tetrafluoro-l,4-dihydro-4-oxo-3-quinolinecarboxylic acid, 0.09g(0.59 mmole) of l,8-diazabicyclo[5.4.0]undec-7-ene, 0.06g(0.59 mmole) of triethylamine, and

0.15g(0.58 mmole) of 3-methylthiomethylpyrrolidine hydroiodide in 10 m/ of acetonitrile was stiired for 4 hours at 6013 , cooled to room temperature, stiired for 3 hours, and evaporated under reduced pressure.

The mixture was diluted with 20ml of water. The precipitate was filtered and recrystallized from medianol : dichloromethane(l : 1) to afford 0.2g of the title compound as pale yellow solid. m.p. : 190 - 19413

Η NMRφpm, CDC1 ₃ ) : 1.48 - 2.43(m, 3H), 2.12(s, 3H), 2.64(d, 2H),

3.43 - 3.99(m, 4H), 6.94 - 7.50(m, 3H), 8.36(s, 1H), 14.49(br, 1H)

Example 16

.Preparation of l-cyclopropyl-6,8-difluoro-7-(4-mercaptopiperidinyl)- 1 ,4-dihydro-4- oxo-3-quinolinecarboxylic acid

A mixture of 0.1g(0.35 mmole) of l-cyclopropyl-6,7,8-trifluoro-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, 0.48g(1.75 mmole) of 4- acetylthiopiperidine trifluoroacetate, and 0.18g(1.78 mmole) of triethylamine in 6

5 ml of dimetiiylsulfoxide was stirred for 3 hours at 18013 and then added witii 10ml of IN HCl.

The resulting solution was stirred for 2 hours at 110 3 , cooled to room temperature, adjusted at pH 7.4 with IN NaOH, and tiien allowed to stand for 1 day. The precipitated product was filtered, dried, and recrystallized from methanol : o dichloromethane(l:l) to afford 0.08g of die tide compound as pale yellow solid.

ΗNMRφpm, NaOD/D ₂ O) : 0.92 - 1.18(m, 4H), 1.34 - 2.10(m, 4H), 2.23 -

3.12(m, 4H), 3.30 - 3.56(m, 1H), 3.56 - 3.64(m, 1H), 7.84(dd, 1H), 8.41(s, 1H)

5 Example 17

Preparation of l-cyclopropyl-6,8-difluoro-7-(3-medιylthio^etidinyl)- 1 ,4-dihydro-4- oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 2, except that 3- methylthioazetidine hydroiodide was used in place of 3-methylthiopyrrolidine 0 hydroiodide, die tide compound was prepared as pale yellow solid.

Η NMRtøpm, NaOD/D ₂ O) : 1.10 - 1.30(m, 4H), 2.14(s, 3H),

3.35 - 3.60(m, 1H), 3.70 - 4.70(m, 5H), 7.81(dd, 1H), 8.70(s, 1H)

5 Example 18

Preparation of l-cyclopropyl-5-amino-6,8-difluoro-7-(3-methyldιiomethylpyr roli- dinyl)- 1 ,4-dihydro-4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 2, except that 3- methylthiomethylpyrrolidine hydroiodide and l-cyclopropyl-5-amino-6,7,8-

trifluoro-l,4-dihydro-4-oxo-3-quinolinecarboxylic acid were used in place of 3- methylthiopyrrolidine hydroiodide and l-cyclopropyl-6,7,8-trifluoro-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, the tide compound was prepared as yellow solid. m.p. : 158 - 16313

Η NMRφpm, CDC1 ₃ ) : 0.94 - 1.20(m, 4H), 1.43 ~ 2.53(m, 3H), 2.14(s, 3H),

2.59(s, 2H), 3.47 - 4.21 (m, 5H), 6.36(br, 2H), 8.54(s, 1H), 14.83(br, 1H)

Example 19

Preparation of l-cyclopropyl-6,8-difluoro-7-(3-mercaptomethylpyιrolidinyl) -l,4- dihydro-4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 2, except that 3- mercaptomethylpyrrolidine trifluoroacetate was used in place of 3-methylthio¬ pyrrolidine hydroiodide, the tide compound was prepared as pale yellow solid, m.p. : 238 - 24313 (decomp.) Η NMRφpm, NaOD/D ₂ O) : 0.94 - 1.23(m, 4H), 1.63 - 3.01 (m, 5H),

2.14(s, 3H), 3.23 - 4.01(m, 5H), 7.50(d, 1H), 8.37(s, 1H)

Example 20

Preparation of l-cyclopropyl-6,8-difluoro-7-[3-(2-pyridylthiomethyl)pyrroli dinyl]- 1 ,4-dihydro-4-oxo-3-quinolinecarboxylic acid In the same manner as described in Example 9, except that 3- (2- pyridylthiomethyl)pyrrolidine trifluoroacetate was used in place of 3-methylthio- metiiylpyrrolidine hydroiodide, the tide compound was prepared as pale yellow solid.

m.p. : 196 - 20013

¹ H NMR(ppm, CDCl ₃ ) : 0.91 - 1.46(m, 4H), 1.50 - 2.82(m, 3H), 3.39(d, 2H),

3.30 ~ 4.24(m, 5H), 6.72 - 7.94(m, 4H), 8.42(d, 1H), 8.67(s, 1H), 14.83(br, 1H)

Example 21

Preparation of l-cyclopropyl-6,8-difluoro-7-(3-phenylthiomethylpyιrolidiny l)-l,4- dihydro-4-oxo-3-quinolinec.arboxylic acid In the same manner as described in Example 9, except that 3- phenylthiomethylpyrrolidine trifluoroacetate was used in place of 3-methylthio¬ methylpyrrolidine hydroiodide, the tide compound was prepared as pale yellow solid. m.p. : 160 - 16413 Η NMRφpm, CDC1 ₃ ) : 0.90 - 1.24(m, 4H), 1.32 - 2.80(m, 3H), 3.10(d, 2H),

3.30 - 4.32(m, 5H), 7.30(s, 5H), 7.80(dd, 1H), 8.69(s, 1H), 14.80(br, 1H)

Example 22 Preparation of l-(2,4-difluorophenyl)-6,8-difluoro-7-[3-(2-pyridylthiomethy l) pyrrolidinyl]-l,4-dihydro-4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 9, except that 3- (2- pyridylthiomethyl)pyrrolidine trifluoroacetate and l-(2,4-difiuorophenyl)-6,7,8- trifluoro-l,4-dihydro-4-oxo-3-quinolinecaiix)xylic acid were used in place of 3- mediylthiomethylpyrrolidine hydroiodide and l-cyclopropyl-6,7,8-trifluoro-l,4- dihydro-4-oxo-3-quinolinecarboxylic acid, the title compound was prepared as pale yellow solid. m.p. : 202 - 20613

¹ H NMRφpm, CDCl ₃ ) : 1.84 ~ 2.72(m, 3H), 3.32(d, 2H),

3.24 - 4.12(m, 5H), 6.81 - 8.34(m, 8H), 8.39(s, 1H), 14.66(br, 1H)

5 Example 23

Preparation of l-(2,4-difluorophenyl)-6-fluoro-7-(3-phenylthiomethylpyrroli dinyl)- 1 ,4-dihydro-4-oxo-3-quinolinecarboxylic acid

In the same manner as described in Example 9, except that 3- phenylthiomethylpyrrolidine trifluoroacetate and l-(2,4-difluorophenyl)-6,7- ι o difluoro-l,4-dihydro-4-oxo-3-quinolinec.arboxylic acid were used in place of 3- methylthiomethylpyrrolidine hydroiodide and l-cyclopropyl-6,7,8-trifluoro-l,4- dihydro-4-oxo-3-quinoline arboxylic acid, the tide compound was prepared as pale yellow solid. m.p. : 180 - 18413 5 Η NMRφpm, CDC1 ₃ ) : 1.56 - 2.82(m, 3H), 3.02(d, 2H), 3.10 - 4.12(m, 4H),

5.76(d, 1H), 6.90 - 8.20(m, 4H), 7.27(s, 5H), 8.42(s, 1H), 15.05(br, 1H) The typical examples of the present compounds were tested for antimicrobial activity in vitro against twenty strains of Gram-positive and Gram- 0 negative microorganisms.

The antibacterial activity in vitro is shown in Table 1. The numerals in the table 1 show minimum inhibitory concentrations(MIC in μg/ml). The minimum inhibitory concentrations were determined according to die agar dilution method recommended by Japan Society of Chemotherapy [Chemotherapy., 29, 76 (1981)]. 5

Table 1. In vitro Antibacterial Activity, MIC (μg/ml)

CD? = Ciprofloxacin

The compound of example 9 was orally administered to determine the LD ₅₀ for a group of male mice. The result was proved to be LD ₅₀ > 3000 mg kg. The antibacterial activity for MRSA(Methicillin Resistant Staphyloccocus Aureus) was tested by die compound of example 9. The results are shown in Table 2.

Table 2. Antibacterial Activity for MRS A (μg/ml)

CIP = Ciprofloxacin