Process of reacting 3-PY-aniline (I) with lower-alkyl acetoacetate (II) and tri-(lower-alkyl) orthoformate (III) to produce lower-alkyl .alpha.-(3-PY-anilinomethylene)acetoacetate (IV), heating lower-alkyl .alpha.-(3-PY-anilinomethylene)acetoacetate (IV), to produce 3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline (V) which is tautomeric with 3-acetyl-4-hydroxy-7-PY-quinoline (VA), reacting V (or VA) with a lower-alkylating agent to produce 3-acetyl-1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-quinoline (VI) and converting VI to 1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-3-quinolinecarboxylic acid (VII), where PY is 4(or 3)-pyridyl or 4(or 3)-pyridyl having one or two lower-alkyl substituents. The compounds of formula VII are known antibacterial agents.

This invention relates to a process for preparing 3-quinolinecarboxylic 
acids and to compositions used therein. 
The invention in a process aspect comprises the four steps of reacting 
3-PY-aniline (I) with lower-alkyl acetoacetate (II), and tri-(lower-alkyl) 
orthoformate (III) to produce lower-alkyl 
.alpha.-(3-PY-anilinomethylene)acetoacetate (IV), heating lower-alkyl 
.alpha.-(3-PY-anilinomethylene)acetoacetate (IV) to produce 
3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline (V) which is tautomeric with 
3-acetyl-4-hydroxy-7-PY-quinoline (VA), reacting V (or VA) with a 
lower-alkylating agent to produce 
3-acetyl-1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-quinoline (VI) and 
converting VI to 
1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-3-quinolinecarboxylic acid (VII), 
where PY is 4(or 3)-pyridyl or 4(or 3)-pyridyl having one or two 
lower-alkyl substituents. The final products (VII) are known antibacterial 
agents. In addition to said combination of the four steps, other process 
aspects of the invention are each individual step and the consecutive 
combinations of two or three steps. 
The invention in its composition aspect resides in the compounds: 
lower-alkyl .alpha.-(3-PY-anilinomethylene)acetoacetate of the formula IV 
##STR1## 
where R is lower-alkyl; 3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline and its 
tautomeric 3-acetyl-4-hydroxy-7-quinoline of the respective formulas V and 
VA 
##STR2## 
and 3-acetyl-1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-quinoline of the 
formula VI 
##STR3## 
where R.sub.1 is lower-alkyl and PY in each of the formulas IV, V, VA and 
VI is defined as hereinabove. Alternatively, the compounds of formulas V 
and VI can be named 3-acetyl-7-PY-4-(1H)-quinolone and 
3-acetyl-1-(lower-alkyl)-7-PY-4-(1H)-quinolone, respectively. 
Preferred process and composition embodiments, because of high 
antibacterial activity of final products and ready availability of 
intermediates are those where PY is 4-pyridyl, 3-pyridyl, 
2-methyl-4-pyridyl and 2,6-dimethyl-4-pyridyl. 
The term "lower-alkyl", as used herein, e.g., as represented by R in 
formula IV or R.sub.1 in formula VI, means alkyl radicals having from one 
to six carbon atoms which can be arranged as straight or branched chains, 
illustrated by methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, 
isobutyl, n-amyl, n-hexyl, and the like. 
Illustrative of the PY substituent in I or the PY substituent in formulas 
IV, V, VA and VI where PY is 4(or 3)-pyridyl having one or two lower-alkyl 
substituents are the following: 2-methyl-4-pyridyl, 
2,6-dimethyl-4-pyridyl, 3-methyl-4-pyridyl, 2-methyl-3-pyridyl, 
6-methyl-3-pyridyl (preferably named 2-methyl-5-pyridyl), 
2,3-dimethyl-4-pyridyl, 2,5-dimethyl-4-pyridyl, 2-ethyl-4-pyridyl, 
2-isopropyl-4-pyridyl, 2-n-butyl-4-pyridyl, 2-n-hexyl-4-pyridyl, 
2,6-diethyl-4-pyridyl, 2,6-diethyl-3-pyridyl, 2,6-diisopropyl-4-pyridyl, 
2,6-di-n-hexyl-4-pyridyl, and the like. Because of ready availability, 
ease of preparation and/or high antibacterial activity of the final 
products, i.e., the 1-(lower-alkyl)-1,4-dihydro-7-[mono(or 
di)-(lower-alkyl)-4-(or 3)-pyridyl]-4-oxo-3-quinolinecarboxylic acids, 
preferred embodiments of this group, as noted above, are those where 4(or 
3)-pyridyl is substituted by one or two methyl, especially the 
2-methyl-4-pyridyl and 2,6-dimethyl-4-pyridyl compounds. 
As shown above, 3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline of formula V is 
tautomeric with 3-acetyl-4-hydroxy-7-PY-quinoline of formula VA. As with 
all tautomeric systems, the rate of the transformation V.revreaction.VA 
and the ratio V/VA are dependent on the thermodynamic environment, 
including the state of aggregation; so that measurements by any particular 
techniques do not necessarily have validity except under the conditions of 
the measurement, thereby, among other consequences, giving rise to 
problems for any simple designation of the physical embodiments. Thus, 
measurements of the infrared spectra, in potassium bromide admixture, or 
in chloroform or mineral oil, indicate existence predominantly as V and 
the names of the compounds herein therefore are preferably based on 
structure V, although it is understood that either or both structures are 
comprehended. 
The intermediate 3-PY-anilines (I) are either known or are prepared from 
known compounds by conventional means. 
The molecular structures of the composition aspects (IV, V, VA and VI) of 
our invention were assigned on the basis of evidence provided by infrared, 
ultraviolet and nuclear magnetic resonance spectra, by chromatographic 
mobilities, and, by the correspondence of calculated and found values for 
the elementary analyses for representative examples. 
The manner of making and using the instant invention will now be generally 
described so as to enable a person skilled in the art of chemistry to make 
and use the same, as follows: 
The preparation of lower-alkyl .alpha.-(3-PY-anilinomethylene)acetoacetate 
(IV) is preferably carried out by heating a mixture of equimolar 
quantities of 3-PY-aniline (I), tri-(lower-alkyl) orthoformate (III) and 
lower-alkyl acetoacetate (II) at about 75.degree.-125.degree. C., 
preferably about 90.degree.-110.degree. C. Although the reaction is 
conveniently run in the absence of any solvent, it can be run using any 
solvent inert under the reaction conditions, such as a lower-alkanol, 
preferably ethanol, acetonitrile, dimethylformamide, benzene, toluene, and 
the like. Preferably, the reaction is run in the presence of a catalytic 
amount of an acidic catalyst, e.g., a strong inorganic acid such as 
hydrochloric acid, sulfuric acid, hydrobromic acid, phosphoric acid, and 
the like; an organic sulfonic acid such as p-toluenesulfonic acid, 
benzenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, and the 
like; a Lewis acid such as zinc chloride, boron trichloride, boron 
tribromide, aluminum trichloride, and the like. Since the reaction most 
likely proceeds first by the reaction of the lower-alkyl acetoacetate with 
the tri-(lower-alkyl) orthoformate to produce lower-alkyl 
(lower-alkoxy)methyleneacetoacetate which then reacts with 3-PY-aniline to 
produce IV, the same compound IV optionally can be prepared by reacting 
3-PY-aniline with the known lower-alkyl 
(lower-alkoxy)methyleneacetoacetate. Thus, the process claimed herein 
comprehends and/or implies the reaction of lower-alkyl acetoacetate with 
tri-(lower-alkyl) orthoformate to produce lower-alkyl 
(lower-alkoxy)methyleneacetoacetate and the reaction of the latter with 
3-PY-aniline to produce lower-alkyl 
.alpha.-(3-PY-anilinomethylene)acetoacetate (IV). 
The reaction of lower-alkyl .alpha.-(3-PY-anilinomethylene)acetoacetate 
(IV) to produce 3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline (V) is carried 
out by heating IV in an inert solvent at about 225.degree.-325.degree. C., 
preferably at about 250.degree.-300.degree. C. Such solvents include 
mineral oil, diethyl phthalate, dibenzyl ether, the eutectic mixture of 
diphenyl and diphenyl ether (Dowtherm.RTM.A), and the like. 
Alternatively, the above two steps can be run consecutively without 
isolation of compound IV. 
The reaction of 3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline (V) or its 
tautomeric 3-acetyl-4-hydroxy-7-PY-quinoline (VA) with a lower-alkylating 
agent to produce 3-acetyl-1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-quinoline 
(VI) is generally carried out by reacting said compound of formula V or VA 
with a lower-alkyl ester of a strong inorganic acid or an organic sulfonic 
acid, said ester having the formula R.sub.1 -An, where An is an anion of a 
strong inorganic acid or an organic sulfonic acid, e.g., chloride, 
bromide, iodide, sulfate, methanesulfonate, benzenesulfonate, and 
p-toluenesulfonate, and R.sub.1 is lower-alkyl. This alkylation is 
preferably run using a slight excess of the alkylating agent. The 
chloride, bromide or iodide is preferred because of the ready availability 
of the requisite lower-alkyl halides; and the reaction is carried out 
preferably in the presence of an acid-acceptor. The acid-acceptor is a 
basic substance which preferably forms freely water-soluble by-products 
easily separable from the product of the reaction, including for example, 
sodium hydroxide, potassium hydroxide, sodium carbonate, potassium 
carbonate, sodium alkoxides, potassium alkoxides, sodium amide, 
diisopropylamine, ethyldiisopropylamine, and the like. The acid-acceptor 
takes up the hydrogen halide (or HAn) which is split out during the course 
of the reaction and also takes up the proton from the 1-position of V or 
from the 4-OH of VA to generate the resulting anion of V or VA. The 
reaction can be carried out in either the presence of absence of a 
suitable solvent, but preferably in a solvent such as lower-alkanol, 
acetone, dioxane, dimethylformamide, dimethyl sulfoxide, hexamethyl 
phosphoramide, or a mixture of solvent, e.g., a mixture of water and a 
lower-alkanol. The reaction is generally carried out at a temperature 
between about room temperature (about 20.degree.-25.degree. C.) and 
150.degree. C., preferably heating on a steam bath in a stirred mixture of 
dimethylformamide and anhydrous potassium carbonate. 
The conversion of 3-acetyl-1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-quinoline 
(VI) to 1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-3-quinolinecarboxylic acid 
(VII) is carried out by reacting VI with an agent capable of converting 
--COCH.sub.3 to --COOH. This is conveniently done by reacting VI with 
chlorine or bromine and an alkali metal hydroxide, preferably sodium or 
potassium hydroxide, or with the corresponding alkali hypohalite. This 
conversion of VI to VII also can be carried out by reacting VI with iodine 
and pyridine followed by reacting the resulting 
1-[1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-3-quinolinecarbonylmethyl]pyridi 
nium iodide with alkali, e.g., aqueous sodium or potassium hydroxide 
solution, to convert 3--COCH.sub.2 N.sup..sym. C.sub.5 H.sub.5 
I.sup..crclbar. to 3--COOH; the reaction with the iodine and pyridine is 
conveniently carried out by heating the reaction mixture on a steam bath 
and the reaction of the resulting pyridinium iodide compound is 
conveniently hydrolyzed in refluxing aqueous sodium or potassium hydroxide 
solution. Alternatively, the conversion of VI to VII is carried out by 
heating VI with dilute aqueous nitric acid, preferably refluxing 20% 
nitric acid. 
Alternatively, the above-described process can be modified by reacting 
N-(lower-alkyl)-3-PY-aniline VIII with lower-alkyl acetoacetate (II) and 
tri-(lower-alkyl) orthoformate (III) to produce lower-alkyl 
.alpha.-[N-(lower-alkyl)-3-PY-anilinomethylene]acetoacetate (IX) and 
heating IX to produce 
3-acetyl-1-(lower-alkyl)-1,4-dihydro-4-oxo-7-PY-quinoline (VI). The 
ring-closure conversion of IX of produce VI is carried out like the 
ring-closure conversion of IV to produce V but preferably using 
polyphosphoric acid at about 175.degree.-235.degree. C.

The best mode contemplated for carrying out the invention is now 
illustrated as follows: 
EXAMPLE 1 
Ethyl .alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate 
A mixture containing 60 g. of 3-(4-pyridyl)aniline, 46 g. of ethyl 
acetoacetate, 52 g. of triethyl orthoformate and about 0.1 g. of 
p-toluenesulfonic acid monohydrate was stirred and heated on a steam bath 
for 3 hours. The reaction mixture was diluted with about 500 ml. of 
cyclohexane and stirred while allowing it to cool to room temperature. The 
mixture was then chilled in an ice bath and the separated solid was 
collected, washed with n-pentane and recrystallized from isopropyl acetate 
to produce 52 g. of ethyl 
.alpha.-[3-(4-pyridyl)-anilinomethylene]acetoacetate, m.p. 
107.degree.-108.degree. C. A second crop of 20 g. of the same material, 
m.p. 106.degree.-108.degree. C., was obtained by concentrating and 
chilling the mother liquor. A sample of this product prepared in another 
run and recrystallized from cyclohexane was found to melt at 
109.5.degree.-110.5.degree. C. 
Following the procedure described above in Example 1 but using in place of 
ethyl acetoacetate and triethyl orthoformate molar equivalent quantities 
of the appropriate lower-alkyl acetoacetate and tri-(lower-alkyl) 
orthoformate, there are obtained: methyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate using methyl 
acetoacetate and trimethyl orthoformate; n-propyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate using n-propyl 
acetoacetate and tri-n-propyl orthoformate; isopropyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate using isopropyl 
acetoacetate and isopropyl orthoformate; isobutyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate using isobutyl 
acetoacetate and triisobutyl orthoformate; and, n-hexyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate using n-hexyl 
acetoacetate and tri-n-hexyl orthoformate. 
EXAMPLE 2 
3-Acetyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline 
To one liter of boiling Dowtherm.RTM. A (eutectic mixture of diphenyl and 
diphenyl ether) was carefully added with stirring 52 g. of ethyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate and the resulting 
mixture was boiled for 11 minutes. The reaction mixture was allowed to 
cool to room temperature (about 25.degree.-30.degree. C.) and allowed to 
stand overnight. The precipitate was collected, washed with a small amount 
of benzene and recrystallized from dimethylformamide to produce 14 g. of 
3-acetyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline (or 
3-acetyl-7-(4-pyridyl)-4(1H)-quinolone), m.p. &gt;300.degree. C. A second 
crop of 13.6 g. of this product, m.p. &gt;300.degree. C., was obtained after 
precipitation from the reaction mixture and recrystallization from 
dimethylformamide. 
3-Acetyl-1,4-dihydro-4-oxo7-(4-pyridyl)quinoline also is produced by 
following the above-described procedure but using in place of ethyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate a molar equivalent 
quantity each of the following lower-alkyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetates: methyl, n-propyl, 
isopropyl, isobutyl or n-hexyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate. 
EXAMPLE 3 
3-Acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline 
To a mixture containing 22 g. of 
3-acetyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline and 200 ml. of 
dimethylformamide was added 22 g. of anhydrous potassium carbonate and the 
resulting mixture was stirred and heated on a steam bath for about 15 
minutes. To said mixture heated on a steam bath was added dropwise with 
stirring a solution of 18 g. of ethyl tosylate in 30 ml. of 
dimethylformamide. The reaction mixture was then stirred over a steam bath 
for two hours and the solvent distilled off in vacuo. The residue was 
shaken well with a mixture of water and chloroform. The layers were then 
separated and the chloroform layer evaporated in vacuo to remove the 
chloroform. The residue was recrystallized once from dimethylformamide and 
once from acetonitrile to produce 18.0 g. of 
3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline (or 
3-acetyl-1-ethyl-7-(4-pyridyl)-4(1H)-quinolone), m.p. 
231.degree.-233.degree. C. 
EXAMPLE 4 
1-Ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid 
To a cold (0.degree. C.) solution containing 3 g. of sodium hydroxide in 28 
ml. of water was added 1.54 ml. of bromine. To the resulting solution kept 
at 0.degree. C. was added with stirring 3.0 g. of 
3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline and the 
resulting reaction mixture was stirred while allowing it to warm up to 
room temperature and then to stand at room temperature for several hours. 
The reaction mixture was then acidified with glacial acetic acid and the 
resulting precipitate was collected and recrystallized twice from 
dimethylformamide, using decolorizing charcoal during the second 
recrystallization, to produce 2 g. of 
1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid, m.p. 
260.degree.-285.degree. C.; this compound was established to be the same 
as an authentic sample of 
1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid by 
side-by-side, thin layer chromatographic comparison wherein the 
chromatographic mobilities and ultraviolet spectra of the two compounds 
were found to be identical. 
The conversion of 3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline 
to 1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid also 
is carried out alternatively as follows: by warming on a steam bath for 90 
minutes a mixture containing 1.46 g. of 
3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline, 2.4 ml. of 
pyridine and 0.86 g. of iodine, allowing the reaction mixture to stand 
overnight at room temperature, removing the excess pyridine in vacuo, 
drying the residue in vacuo at 130.degree. C., heating the residue under 
reflux for 1 hour in 35 ml. of 1N potassium hydroxide solution in 
diethylene glycol which contained 1 ml. of water, diluting the solution 
with water, acidifying the solution with hydrochloric acid, extracting the 
mixture with ether, extracting the product from the ether with dilute 
sodium bicarbonate, decolorizing the resulting aqueous solution with 
decolorizing charcoal, acidifying the resulting solution and collecting 
the crystalline 
1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid. 
In another conversion of the 3-acetyl compound to 
1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid, a 1.46 
g. portion of said 3-acetyl compound is refluxed for 5 hours with 35 ml. 
of 20% nitric acid, the reaction mixture is evaporated to dryness in 
vacuo, the residue is boiled for 15 minutes with acetic acid, the 
separated 3-carboxylic acid is collected and recrystallized from 
acetonitrile. 
Following the procedures described in Example 1 but using in place of 
3-(4-pyridyl)aniline a molar equivalent quantity of the appropriate 
3-PY-aniline, the compounds of Examples 5-11 are obtained: 
Example 5 -- ethyl .alpha.-[3-(3-pyridyl)anilinomethylene]-acetoacetate 
using 3-(3-pyridyl)aniline. 
Example 6 -- ethyl 
.alpha.-[3-(2-methyl-4-pyridyl)anilinomethylene]acetoacetate using 
3-(2-methyl-4-pyridyl)aniline. 
Example 7 -- ethyl 
.alpha.-[3-(3-methyl-4-pyridyl)anilinomethylene]acetoacetate using 
3-(3-methyl-4-pyridyl)aniline. 
Example 8 -- ethyl 
.alpha.-[3-(2-ethyl-4-pyridyl)anilinomethylene]acetoacetate using 
3-(2-ethyl-4-pyridyl)aniline. 
Example 9 -- ethyl 
.alpha.-[3-(3-ethyl-4-pyridyl)anilinomethylene]acetoacetate using 
3-(3-ethyl-4-pyridyl)aniline. 
Example 10 -- ethyl 
.alpha.-[3-(2,6-dimethyl-4-pyridyl)anilinomethylene]acetoacetate using 
3-(2,6-dimethyl-4-pyridyl)aniline. 
Example 11 -- ethyl 
.alpha.-[3-(3,5-dimethyl-4-pyridyl)anilinomethylene]acetoacetate using 
3-(3,5-dimethyl-4-pyridyl)aniline. 
Following the procedure described in Example 2 but using in place of ethyl 
.alpha.-[3-(4-pyridyl)anilinomethylene]acetoacetate a molar equivalent 
quantity of the appropriate ethyl 
.alpha.-(3-PY-anilinomethylene)acetoacetate, the compounds of Examples 
12-18 are obtained: 
Example 12 -- 3-acetyl-1,4-dihydro-4-oxo-7-(3-pyridyl)quinoline using ethyl 
.alpha.-[3-(3-pyridyl)anilinomethylene]acetoacetate. 
Example 13 -- 3-acetyl-1,4-dihydro-7-(2-methyl-4-pyridyl)-4-oxoquinoline 
using ethyl .alpha.-[3-(2-methyl-4-pyridyl)anilinomethylene]acetoacetate. 
Example 14 -- 3-acetyl-1,4-dihydro-7-(3-methyl-4-pyridyl)-4-oxoquinoline 
using ethyl .alpha.-[3-(3-methyl-4-pyridyl)anilinomethylene]acetoacetate. 
Example 15 -- 3-acetyl-7-(2-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline 
using ethyl .alpha.-[3-(2-ethyl-4-pyridyl)anilinomethylene]acetoacetate. 
Example 16 -- 3-acetyl-7-(3-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline 
using ethyl .alpha.-[3-(3-ethyl-4-pyridyl)anilinomethylene]acetoacetate. 
Example 17 -- 
3-acetyl-1,4-dihydro-7-(2,6-dimethyl-4-pyridyl)-4-oxoquinoline using ethyl 
.alpha.-[3-(2,6-dimethyl-4-pyridyl)anilinomethylene]acetoacetate. 
Example 18 -- 
3-acetyl-1,4-dihydro-7-(3,5-dimethyl-4-pyridyl)-4-oxoquinoline using ethyl 
.alpha.-[3-(3,5-dimethyl-4-pyridyl)anilinomethylene]acetoacetate. 
Following the procedure described in Example 3 but using in place of 
3-acetyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-quinoline and ethyl tosylate a 
molar equivalent quantity each of the respective appropriate 
3-acetyl-1,4-dihydro-4-oxo-7-PY-quinoline and/or alkylating agent, the 
compounds of Examples 19-26 are obtained: 
Example 19 -- 3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline 
using 3-acetyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline and diethyl 
sulfate or ethyl iodide. Similarly, using said 7-(4-pyridyl) compound and 
a molar equivalent quantity of dimethyl sulfate, n-propyl iodiode, 
isobutyl bromide or n-hexyl chloride in place of ethyl tosylate, there is 
obtained 3-acetyl-1,4-dihydro-1-methyl-4-oxo-7-(4-pyridyl)quinoline, 
3-acetyl-1,4-dihydro-4-oxo-1-n-propyl-7-(4-pyridyl)quinoline, 
3-acetyl-1,4-dihydro-1-isobutyl-4-oxo-7-(4-pyridyl)quinoline or 
3-acetyl-1-n-hexyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline, respectively. 
Example 20 -- 3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(3-pyridyl)quinoline 
using 3-acetyl-1,4-dihydro-4-oxo-7-(3-pyridyl)quinoline. 
Example 21 -- 
3-acetyl-1-ethyl-1,4-dihydro-7-(2-methyl-4-pyridyl)-4-oxoquinoline using 
3-acetyl-1,4-dihydro-7-(2-methyl-4-pyridyl)-4-oxoquinoline. 
Example 22 -- 3-acetyl-1-ethyl-1,4-dihydro-7-(3-methyl-4-pyridyl)quinoline 
using 3-acetyl-1,4-dihydro-7-(3-methyl-4-pyridyl)-4-oxoquinoline. 
Example 23 -- 
3-acetyl-1-ethyl-7-(2-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline using 
3-acetyl-7-(2-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline. 
Example 24 -- 
3-acetyl-1-ethyl-7-(3-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline using 
3-acetyl-7-(3-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline. 
Example 25 -- 
3-acetyl-1-ethyl-1,4-dihydro-7-(2,6-dimethyl-4-pyridyl)-4-oxoquinoline 
using 3-acetyl-1,4-dihydro-7-(2,6-dimethyl-4-pyridyl)-4-oxoquinoline. 
Example 26 -- 
3-acetyl-1-ethyl-1,4-dihydro-7-(3,5-dimethyl-4-pyridyl)-4-oxoquinoline 
using 3-acetyl-1,4-dihydro-7-(3,5-dimethyl-4-pyridyl)-4-oxoquinoline. 
p Following the procedure described in Example 4 but using a molar 
equivalent quantity of the appropriate 
3-acetyl-1-alkyl-1,4-dihydro-4-oxo-7-PY-quinoline in place of 
3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridyl)oxoquinoline, there are 
obtained the corresponding 
1-alkyl-1,4-dihydro-4-oxo-7-PY-3-quinolinecarboxylic acids of Examples 
27-37. 
Example 27 -- 
1,4-dihydro-1-methyl-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid using 
3-acetyl-1,4-dihydro-1-methyl-4-oxo-7-(4-pyridyl)quinoline. 
Example 28 -- 
1,4-dihydro-4-oxo-1-n-propyl-7-(4-pyridyl)-3-quinolinecarboxylic acid 
using 3-acetyl-1,4-dihydro-4-oxo-1-n-propyl-7-(4-pyridyl)quinoline. 
Example 29 -- 
1,4-dihydro-1-isobutyl-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid 
using 3-acetyl-1,4-dihydro-1-isobutyl-4-oxo-7-(4-pyridyl)quinoline. 
Example 30 -- 
1-n-Hexyl-1,4-dihydro-4-oxo-7-(4-pyridyl)-3-quinolinecarboxylic acid using 
3-acetyl-1-n-hexyl-1,4-dihydro-4-oxo-7-(4-pyridyl)quinoline. 
Example 31 -- 1-ethyl-1,4-dihydro-4-oxo-7-(3-pyridyl)-3-quinolinecarboxylic 
acid using 3-acetyl-1-ethyl-1,4-dihydro-4-oxo-7-(3-pyridyl)quinoline. 
Example 32 -- 
1-ethyl-1,4-dihydro-7-(2-methyl-4-pyridyl)-4-oxo-3-quinolinecarboxylic 
acid using 
3-acetyl-1-ethyl-1,4-dihydro-7-(2-methyl-4-pyridyl)-4-oxoquinoline. 
Example 33 -- 
1-ethyl-1,4-dihydro-7-(3-methyl-4-pyridyl)-3-quinolinecarboxylic acid 
using 3-acetyl-1-ethyl-1,4-dihydro-7-(3-methyl-4-pyridyl)quinoline. 
Example 34 -- 
1-ethyl-7-(2-ethyl-4-pyridyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid 
using 3-acetyl-1-ethyl-7-(2-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline. 
Example 35 -- 
1-ethyl-7-(3-ethyl-4-pyridyl)-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid 
using 3-acetyl-1-ethyl-7-(3-ethyl-4-pyridyl)-1,4-dihydro-4-oxoquinoline. 
Example 36 -- 
1-ethyl-1,4-dihydro-7-(2,6-dimethyl-4-pyridyl)-4-oxo-3-quinolinecarboxylic 
acid using 
3-acetyl-1-ethyl-1,4-dihydro-7-(2,6-dimethyl-4-pyridyl)-4-oxoquinoline. 
Example 37 -- 
1-ethyl-1,4-dihydro-7-(3,5-dimethyl-4-pyridyl)-4-oxo-3-quinolinecarboxylic 
acid using 
3-acetyl-1-ethyl-1,4-dihydro-7-(3,5-dimethyl-4-pyridyl)-4-oxoquinoline.