SE433215B - PROCEDURE FOR PREPARING 2-PIPERAZINYL-PYRIDO- / 2,3-D / PYRIMIDINE DERIVATIVES - Google Patents

Description

Z wherein R 1 represents a monohydric atom or an acyl group and R 2 represents a lower alkyl group having 1 to 0 carbon atoms.

The term "acyl group" as used in the present specification and claims means a carbonic or carhoxylic acid radical, such as a lower alkanoyl group, such as formyl, acetyl, trifluoroacetyl or propionyl, a lower alkoxycarbonyl group, such as methoxycarbonyl or ethoxycarbonyl, and a lower alkyl alkoxycarbonyl group e.g. benzyloxycarbonyl.

The compound Z1] is sometimes obtained as hydrates, which are also included. In the present specification, its hydrates are described as comprising the compound [1] in free form, other than salts of the compound LII. Compounds which are relatively similar to the compound [1] are described in British Patent Specification 1,129,358 (published October 2, 1968) and German Publication No. 2,143,369 (published March 9, 1972) as antibacterial agents.

When working in an attempt to prepare antibacterial agents which are more useful than the known compounds, it has now been found that by introducing a piperazine group in the 2-position on the pyrido-12,3-dipyrimidine nucleus one can obtain a compound with characteristic antibacterial effect (especially against Pseudomonas aeruginosa).

The compound [I] is synthesized as follows: 1st step A compound of the following formula // COOR N Z / _ \ / Q / I coonz R 1 ~ TV H [W] wherein Rloch Rzlwr the above definition; subjected to intramolecular cyclization during heating to give a millan product of the following formula in [H11 wní R, and R, as defined above. The reaction is carried out by heating the compounds [II] directly or in a high-boiling solvent such as diphenyl ether, o-dichlorobenzene, diphenylene oxide, dibutyl phthalate or mixtures thereof. Suitable heating temperature is 140-2600C.

It is also possible to carry out the cyclization reaction in the presence of a conventional cyclization agent, such as polyphosphoric acid, polyphosphoric acid alkyl ester, concentrated sulfuric acid or phosphorus pentoxide. When polyphosphoric acid, polyphosphoric acid alkyl ester or phosphorus pentoxide is used as the cyclizing agent, the reaction is usually carried out in a solvent such as benzene, dioxane or dimethylformamide. When concentrated sulfuric acid is used, the reaction is usually carried out in a solvent such as acetic anhydride or acetic acid. Of course, depending on its properties, the cyclizing agent can also be used as a solvent. If ring closure is used, the reaction is carried out at relatively low temperatures. 2nd Step Compound [III] is further subjected to alkylation reaction to give a compound of the following formula [II] and R 2 has the above definition.

Known alkylating agents can be used in this reaction. Specific examples include ethyl halides, such as ethyl iodide, and ethyl esters, such as diethyl sulfate, ethyl p-toluenesulfonate or triethyl phosphate.

The reaction is usually carried out by reacting the compound [III] with a stoichiometric amount of the alkylating agent in an inert solvent at an elevated temperature. If desired, the alkylating agent can be used in excess. The solvent may be either anhydrous or aqueous. Examples of solvents are ethanol, dioxane, dimethylformamide, dimethylsulfoxide and water. The reaction is favored by the addition of an acid acceptor, for example a base, such as an alkali carbonate, an alkali hydroxide, a 10 U! Alkali metal alkoxide, sodium hydride, triethylamine, benzyltrimethylammonium hydroxide. When the alkylating agent is allowed to act in an aqueous solvent, the carboxylic acid ester moiety sometimes undergoes hydrolysis depending on the reaction conditions, and is thus converted to a free carboxylic acid. Furthermore, when compounds of formula (III), wherein R 1 represents a hydrogen atom, are alkylated, the N-ethylated product in the 4-position on the piperazine core can be prepared together with the N-ethylated product in the 8-position on the pyridine. 2,3-d) the pyrimidine nucleus. The products can of course be easily separated from each other e.g. by recrystallization. 3rd step The compound [II] is finally subjected to hydrolysis reaction and then the compound [I] or its salt is obtained.

The hydrolysis reaction in the process is carried out by contacting the compound (ii) with water. Usually, the reaction is carried out, for acceleration thereof, in the presence of a catalyst, such as an acid or base.

Examples of the acid are inorganic acids, such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid or phosphoric acid, and organic acids, such as acetic acid, oxalic acid or toluenesulfonic acid.

Examples of the base are alkali metal hydroxides, such as sodium hydroxide or barium hydroxide, alkali metal carbonates, such as sodium carbonate or potassium carbonate, and sodium acetate.

This reaction can also be carried out by directly heating the material in the presence of the acid described above, and then adding water. The solvent is usually water, but depending on the properties of the material, an aqueous solvent such as ethanol, dioxane, ethylene glycol dimethyl ether, benzene or acetic acid can also be used. The reaction temperature may be room temperature, but is usually SO-ZOOOC, preferably 70-120 ° C.

When this reaction is carried out under the mild conditions, either an acyl group (R1-) or an ester group (RZ-) in the formula [II] can be hydrolyzed. In such a case, the partially hydrolyzed compound is further hydrolyzed to give the compound Älj.

The above reactions can be shown schematically as follows: 790Û33lr ~ 9 5 * m2 É i {\ COORq cyclization R1 _ \ / 1i S1 / \\\ / \\ N / d H IV "oo I '-I, \. / 2 i . \ cooR, * l fl / I, \\. alkylation If / I * I “| 1“ \\ ~ š,., '/ \' \\ J raï-x N '\ 5 Rï-ß; \ / * N / "N \ _ / HH 2 5 III II Û k 'coon N4 \ LI weläè \ L, / kN / \ N \\ __./ ÉZHS I (RT and R2 have the above definition).

The starting compound used in this process is prepared by reacting the corresponding 2- (1-piperazinyl) -4-aminopyrimidine with alkoxymethylene malonate according to the procedure described in British Patent Specification 1. 129 358.

The compound Ål] prepared in the above procedure can be isolated and purified by conventional methods. The compound [lf can be prepared in the free state or in the form of a salt depending on the reaction conditions. Furthermore, the compound [I] can be converted into pharmaceutically acceptable amine salts or carboxylic acid salts by treatment with an acid or an alkali, or vice versa. The acid can consist of a number of organic and inorganic acids, the following being examples: hydrochloric acid, acetic acid, lactic acid, succinic acid, oxalic acid and methanesulfonic acid. The antibacterial effects of the present compound [lf are shown in Tables I-IV together with those for compounds described in the British Patron's Journal or German Publication. The Behrens-Kaerbcr procedure (Arch. Exp. Path. Pharm., In Tables [I-IV), the ED values were calculated according to 480 (19311]. The compounds Pa ooh AT-616 consist of the following Compound PA: 5,8-Dihydro-8-ethyl-2-pyrrolidino-5-oxopyrido- (2,3-d) pyrimidine-o-carboxylic acid is the most valuable compound described in the British patent specification.

Compound AT-616: 5,8-Dihydro-8-ethyl-2- (3-hydroxypyrrolidine) -5-oxopyrido (2,3-dipyrimidine-O-carboxylic acid is the most valuable compound described in German Offenlegungsschrift 1) In vitro_antibacterial effect against 3 bacterial strains Table 1 in 'å;' '' 3 = MIC (pm / mg): Compound ~ Staphylococcus Escherichis | Pseudomonas aureus coli aeruginosa Tefal ím fl * (42 ÄÉPÉÉiJ 'íí fl ë i -_ 1' so 1 i io.> ~ 1! * - "" '"PA 10 1 1 100, E ”AT-616 30 1 f 100 The minimum inhibitory concentration (MIC) was determined by the well-known serial dilution method.

Experimental conditions:.

Medium: nutrient broth, pH 7; 0 (5 ml / tube) Inoculum: 1 drop 1:10 - dilution of a broth culture; overnight, per tube Incubation temperature and time: 37 ° C for 48 h Z) Efficacy in vivo against systemic infection with Psvudomnnas aorugínosa in mice 5 10 15 20 vsoozza-9 I fl ëilll T - ------- - - ~ »- .___...., V,; _, ______________ ~ _y Förening Väg nos (m§ / kg) '5950 nr zoo 100 50 25 12,5 0,3 3,1; (" @ / kg) ¿1 ip _ - - 8/8 8/8 4/8 z / s 1/8 10,5 v po 8/8 4/8 0/8 - _ _ _ 100, PÅ É íP 1 _ 0 / 3 - - - - - '> 1o0 P0 @ ° / 3 - - - - - - E> z00 AT-610: ip; _ 3/3 _ _ _ _ _ f> .00 1 “P0' l / 8 - - ~ - - - š> z00 1 The figures in the table show the number of surviving mice / the total number of mice 0/8 means that all of 8 mice died 8/8 means that all 8 mice survived: The survival rate for untreated control was 0/8.

Experimental conditions: 3) Efficacy in Organism: Pseudomonas aeroginosa No. 12 Mice: Male mice (ddY-S) weighing about 20 g Infection: Intraperitoneal infection with S0-100 LD50 of a bacterial suspension in 4% gastric mucin (approx. 5 x 103 cells / mouse) Medication: Twice, about 5 minutes resp. 6 hours after infection Drug: An alkaline solution for parenteral administration and a suspension in 0.2% CMC for oral administration Mortality observation: 7 days ip: intraperitoneal administration po: oral administration vivo against systemic infection with Salmonella typhímurium in mice Table III , 8 ... ill.

Is _ Vi I DOS (mg / Rs) “D50 -“ nl 1 av 1 ° ¶¿f “¥ 5 Y 100 so .zs 12,5 6,» (mg / kg) l 1 1 i 1 1 å § 1 ap \ - - 8/8 8/8 4/8 1 0.3 | I po 1 - 8/8 8/8 4/8 U / S 1 ll, 5 i! PA ip '9/10 s / 10 3/10 0/10 - § 13,5: po 10/10 4/10 3/10 U / 10 - - 40,7 10 15 20 ZS 30 790033lP9 i Síffcrvärdena i tabellen viser the number of surviving mice / the total number of mice. 0/8 means that all of S mice are dead. 8/8 means that all 8 mice survived. The survival rate for untreated control was 0 / S.

Experimental conditions: Organism: Salmonella typhimurium S-9 Mice: Male mice (ddY-S) weighing about 20 g Infection: Intraperitoneal infection with S0-100 LD 0 of a bacterial suspension in nutrient broth (about 105 cells / mouse) Medication: Twice daily for 4 days from the day of infection.

An alkaline solution for parenteral administration Drug: ring and a suspension in 0.2% CMC for oral administration Observation: 14 days ip: intraperitoneal administration po: oral administration 74) Acute toxicity in mice Abeii vl Dose tmg / kgrwuww_ LD i ' . tubes '' "-50 i ing 5 Vag, g imon zooo__g__1ooo son (mg / kg) 5 I 1 i iv 6 i - _ o / 6 6/6 700 po i 6/6 6/6 i - -> 4ooo The numerical values in the table shows the number of surviving mice / the total number of mice. U / 6 means that all of 6 mice died and 6/6 means that all mice survived.7 In Compound was in alkaline solution for intravenous administration and for oral administration in a suspension, containing 0.2% CMC, and administered to male mice (ddY-S) weighing about 20 g. After 7 days, the mortality rate was recorded and the LD50 value was estimated iv: intravenous administration po: oral administration The clinical dosage of Compound I depends on body weight, age and route of administration, but is generally in the range of 100 mg - 5 g / day, preferably 200 mg - 3 g / day.

The following examples illustrate the preparation of compounds [1] and the novel intermediates thereof. Example 20 1 Ethyl 1- (J-acetyl-1-piperazinyl) -5,8-dihydro-5-oxopyrido (2,3-d) -pyrimidine-O-carhoxylate To 16 ml of diphenyl ether heated to 250-ZSSOC, 2.0 g of diethyl N-12- (4-acetyl-1-piperazinyl-4-pyrimidinyl] -uminomethylene malonate was added with stirring, gentle reflux was continued for 10 minutes and then the mixture was allowed to cool to room temperature.

To the mixture was added 12 ml of n-hexane, and the resulting precipitate was collected, washed with ethanol and recrystallized from ethanol to obtain 1.52 g of the product, m.p. 300-SUZOC.

Example 2 The following compounds were prepared in a similar manner to that of Example I: ethyl 5,8-dihydro-2- (4-formyl-piperazinyl) -5-oxopyrido-β, 3-d] -pyrimidine-6-carboxylate (m.p. above SOOOC), ethyl 5,8-dihydro-2- (4-ethoxycarbonyl-1-piperazinyl) -5-oxopyrido-ZÉ, 3-dipyrimidine-6-carboxylate (m.p. above SOOOC), ethyl-5 , 8-dihydro-Z- (4-trifluoroacetyl-1-piperazinyl) -5-oxopyrido-12,3-dipyrimidine-6-carboxylate, ethyl 5,8-dihydro-Z- (1-piperazinyl) -5-oxopyridolyl , 3-d] pyrimidine-6-carboxylate.

Example 3 Ethyl 2- (4-acetyl-1-piperazinyl) -S, 8-dihydro-8-ethyl-5-oxopyrido [1,3-d] pyrimidine-6-carboxylate To a suspension of 4.0 g of ethyl 2- (4-Acetyl-1-piperazinyl) -5,8-dihydro-5-oxopyridoline, 3-dipyrimidine-6-carboxylate and 6.0 g of potassium carbonate in 100 ml of 50% aqueous ethanol were added a total of 5.5 ml of diethyl sulfate in three portions while stirring and the mixture was allowed to react for 2 hours at room temperature.

The reaction product was extracted with chloroform and the extract was dried over anhydrous magnesium sulfate, followed by evaporation of the solvent to give a crystalline residue, to which was added n-hexane. The crystals were collected and recrystallized from a mixture of n-hexane and acetone to obtain 3.4 g of the product, m.p. 208-210 ° C with decomposition.

Example 4 Ethyl 2- (1-piperazinyl-5,8-dihydro-8-ethyl-5-oxoepyridoyl, 3-d] pyrimidine-6-carhoxylate To a solution of 1.5 g of ethyl-5,8- dihydro-2- (1-piperu: inyl Io 15 20 25 30 35 40 40-oxopyrido [3,3-d] pyrimidine-6-carboxylate in 60 ml of a 10% aqueous solution containing sodium carbonate was added After completion of the reaction, three 10 ml portions of diethyl sulphate neutralize the resulting mixture with acetic acid. The precipitate was collected and recrystallized from dimethylformamide to give 0.8 g of ethyl 2- (1-piperazinyl) -5,8-dihydro-8- ethyl S-oxopyridolyl, 3-d-pyrimidine-6-carboxylate, mp 156-158 ° C.

Example 5 5,8-Dihydro-8-ethyl-Z- (1-piperazinyl) -5-oxopyridolyl, 3-d] pyrimidine-6-carboxylic acid (compound ÜJJ 5.0 g ethyl-5,8-dihydro-8 Ethyl 5-oxo-2- (1-piperazinyl) pyrido [3,3-d] pyrimidine-6-carboxylate was dissolved in 30 ml of a 7% aqueous solution of sodium hydroxide by heating to QOOC for 20 minutes. After cooling, it was neutralized. formed solution with acetic acid to give a precipitate which was collected and recrystallized from dimethylformamide to give 4.3 g of the product, m.p. 253 DEG-25 DEG C., Example 6 2- (4-acetyl-1-piperazinyl) -5,8-dihydro-8-ethyl-5-oxopyrido [1,3-d] pyrimidine-6-carboxylic acid 1 5.0 g of ethyl 2- (4-acetyl-1-piperazinyl) -5,8-dihydro -8-Ethyl-S-oxopyridolyl, 3-dipyrimidine-6-carboxylate was dissolved in 35 ml of an 10% aqueous solution of sodium carbonate by heating to 90 ° C for 30 minutes. The resulting solution was filtered to remove insoluble matter. and the filtrate was neutralized with acetic acid to give a precipitate as up was collected and recrystallized from a mixture of benzene and chloroform. 4.1 g of the product with a melting point of 298-300 ° C were obtained.

Example 7 - 5,8-Dihydro-8-ethyl-2- (1-piperazinyl) -5-oxopyrido-12,3-dipyrimidine-6-carboxylic acid (Compound E11) (A) 2.0 g 2- (4- acetyl-1-piperazinyl) -5,8-dihydro-8-ethyl-5-oxopyridolyl, 3-d] pyrimidine-6-carboxylic acid was dissolved in 40 ml of a 10% aqueous solution of sodium hydroxide by heating to 90- 95 ° C for 1.5 hours. The resulting solution was treated with decolorizing carbon and filtered. The filtrate was neutralized with acetic acid to give 1.6 g of the product in the pure state and with a melting point of 252-ZSSOC.

(B1 1.0 g of ethyl Z- (4-acetyl-1-piperazinyl) -5,8-dihydro-8-cry] -S-oxopyrido [3,3-d] pyrimidine-6-carboxylate was dissolved in 30 ml of 7900334 Neutralization of the reaction mixture with acetic acid under cooling gave a crude solid which was recrystallized from dimethylformamide to give 1.1 g of the product in sodium hydroxide solution by heating to 90 DEG-95 DEG C. for 1 hour. Example 5 5,8-Dihydro-8-ethyl-2- (1-piperazinyl) -5-oxopyridol fi, 3-d] pyrimidine-6-carboxylic acid (compound [í]) The procedure described in Example 7 was followed. (A) using 5,8-dihydro-Z- (4-ethoxycarbonyl-1-piperazinyl) -8-ethyl-5-oxopyrido [2,3-c] pyrimidine-6-carboxylic acid to give 5,8- dihydro-8--ethyl-2- (1-piperazinyl) -5-oxopyridolyl, 3-d] pyrimidine-6-carboxylic acid, m.p. 253-255 ° C.

Claims (1)

1. vsuossu ~ 9 lä. Claims for the preparation of a compound of the formula nl 'ç; \\\ \\ ïe / * coonz 111 \ Rfw NN // N wherein R 1 represents a hydrogen atom or an acyl group and R 2 represents a lower alkyl group having 1 to 6 carbon atoms, käne - drawn from the fact that one heats a compound of the formula * 4; à \\ coon N l <: 2 II cooR Iv / \ \, 2 R1-N NNN // g! Wherein R 1 and R 2 have the above definition, to effect intramolecular cyclization and to give a compound of formula [III] OV & n.