SU479294A3 - Method for preparing 1,8-naphthyridine derivatives - Google Patents

Description

The eca group that is attached to the dinasaphthal group through a nitrogen atom (for example, morpholyl, piperidyl, nirrolidinyl), acyl (eg, acetyl, benzoyl), alkoxycarbylnilkyl (narp.mer, it is. hydroxycarbonylmethyl, 2-ethoxycarbo, nyl ethyl.). Irimer, ethoxycarbonyl) or other carboxylic acid derivatives (for example, nitrile, carboxamido, hydrazide).

Cs is preferably alkyl with 1-6 carbon atoms: (for example, methyl, ethyl), ari (for example, phenyl); aralkyl (for example, benzyl), windows, alkoxy (for example, ethoxy), amshu, acylamio (for example, acetylamino) or other carboxylic acid derivatives (for example, ethoxycarbonyl, carboxamide, nitrile).

Diphyl oil, distillate oil from petroleum, or a fraction of mixed oil are used as inert solvents. The required reaction rate can be achieved by holding it at a temperature between 150 and 400 ° C.

The compounds of formula (I) thus obtained exhibit keto-enol tautomerism:

The compounds of formula (I) can be converted to salts by reaction with an organic or inorganic acid. It is preferable to prepare salts by adding acids such as salt, seria, chlorine, formic acid, uksuspa, trifluoroksuon, maleic, fumaric, etc.

Example 1. 2.32 g of 3-ethoxycarbonyl-6-methyl-4-oxo-4H-pyrido- (1,2-a) -pyrimidine is added to 25 ml of diphyl oil having a temperature of 250 ° C. The solution is heated at this temperature for 25 minutes, after which it is cooled to room temperature, and the solid reaction mixture is diluted with 15 ml of petroleum ether. The crystals are filtered off and washed with petroleum eff: ir.

1.9 g (82%) of brown 3-ethoxycarbonyl-7-methyl-4-oxo-1,4-dihydro-1,8 naphthyrpdine with m.p. 268-270 ° C. After non-recrystallization from a 10-fold amount of dimethylformamide, t.nl. 272-273 ° C.

Calculated,%: C 62.10; P 5.17; N 12.06.

Found,%: C 62.72; H 5.08; N 12.22.

When using 3-acetyl-6-methyl-4H-nirido- (1,2a) -pyrimidine as the starting compound, 3-acetyl-7-methyl-4-oxo-1, 4-dihydro-1,8-1-aphtyridine, t. square above .

Example 1 2. 1.5 g of 3-phenyl-6-methyl-4-oxo-4P-pyrido- (1,2-a) -pyrimidine are added

to 30 -ML of distilled oil from oil having a temperature of 340 ° C, after which the solution is stirred at 340-350 ° C for 15 minutes and cooled to room temperature. Upon cooling, Yoshiat crystals. 60 ml of gasoline are added for the semi-crystal precipitation. The crystals are filtered, washed with gasoline. 1.45 g (97%) of dark brown 3-phenyl-7-methyl-4oxo-1, 4-diggred-1,8-naphthyrndnna with m.p.nl are obtained. . When non-recrystallization from 30-crater amount of dimethylformamide t, pl. 215317 ° C

Calculated,%: C 76.13; H 5.12; N 11.86. Found,%: C 75.85; H 5.10; N 11.63.

When using as the original

Compounds 3,6-dimethyl-4-oxo-4H-nirido (1,2-a) -pyrimidine get 3,7-dimethyl-4oxo-1, 4-dihydro-1,8-naphthyridine (m.p.

280С).

When using as the starting compound 2,6-dimethyl-4-oxo-4H-pyrido (1,2-a) -pyrimidine, 2,7-dimethyl-4oxo-1, 4-dihydro-1,8-naphthyridine (t pl.

320-323 ° C).

When using 3- (ethoxycarbonylmethyl) -6-methyl-4-oxo-4H-pyrido- (1,2-a) -pyrnmidip as the starting compound, 3- (ethoxycarbonylmethyl) -7-methyl-4oxo-1, 4 is obtained. -dihydro-1,8-naphthyridine (mp. above 300 ° C).

Subject invention

1. Method for preparing 1,8-naphT1 derivatives (p1idine of general formula (I)

wherein RI and R2 are single or different and are hydrogen, halogen, alkyl, substituted alkyl, aryl, substituted aryl, aralkyl, alkoxy, arlox-si, aralkoxy, amino, acylamino, alkylmnio, dialkylamino, nitrogen-containing monocyclic heterocyclic , irione to diazaphtalenovoy group through the nitrogen atom, acyl, alkoxycarboiylalkyl, alkoxycarbonyl-primer;

Cs is alkyl, aryl, aralkyl, hydroxyl, alkoxy, alsio, acylamino, but halogen;

R4 is hydrogen, alkyl, aryl, aralkyl, halogen, nitro, alkoxy, hydroxy, amino, acylamino-primer, or their salts, characterized in that the compound of general formula (II)

I-R, -Ri

In R 5, in which R, Ra, Ra and R4, have the above values, isomerisacin is brought up at an elevated temperature in an inert solvent, followed by separation of the target product-5 hectares OR by non-recognition of it in a salt by known methods. 6 2. A method according to claim 1, characterized in that as an inert solvent there is used diphyl oil, distilled oil of oil or mineral oil fraction, 3. Method according to nn. 1 and 2, characterized in that the process is carried out at a temperature of 150-400 ° C.