NL8301739A - METHOD FOR SEPARATING ENANTIOMERS OF 2,3,3A, 4,5,6-HEXAHYDRO 1H-INDOLE 3,2,1-DENAFTYRIDINE-1,5, THE HEXAHYDROENANTIOMERS AND THE THERAPEUTIC USE THEREOF. - Google Patents

Description

* -1- 23154 / Vk / mb

Short designation: Process for separating enantiomers of 2,3,3a, 4,5,6-hexahydro 1H-indole, 3,2,1-de] [naphthyridine-1,5j, the hexahydroantiantiomers and their therapeutic use.

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The present invention relates to 2,3,3a, 4,5,6-hexahydro 1H-indole, 3,2,1-de-naphthyridin-1,5-enioriorers and their addition salts with pharmaceutically acceptable acids, their preparation and therapeutic application.

10 French patent 2,494,693, corresponding to the

Dutch patent application 8105282, describes inter alia the racemate of 2.3, 3a, 4,5,6-hexahydro 1H-indole, 3,2,1-deJ [naphthyridine-1,5j, corresponding to formula 1, shown on the formula sheet . In the structure of this compound, the carbon atom at position 3a 15 is asymmetrically substituted, whereby two optical antipodes are obtained.

Either of the two enantioraers can be separated thanks to the intermediate preparation of the addition salt and one of the antipodes which is optically active from a chiral acid such as bis-2,3- (4-methylbenzoyloxy) -20 butanedl carboxylic acid, 3-broora 8- or 10-camphor sulfonic acid, 10-camphor sulfonic acid, tartaric acid, N-fct-methylbenzyl) monoamide of phthalic acid, malic acid or mandelic acid.

The salt formation takes place between room temperature and the boiling point of the solvent, starting from a mixture of the enantiomers of formula 1, for example starting from the racemate in the form of the base, dissolved in a suitable solvent such as an alcohol, preferably ethanol.

The two diastereoisomeric salts thus obtained are then separated by fractional crystallization.

After the separation, they can be separated from the chiral acid, after which they are converted into the addition salt in the form of a physiologically acceptable acid.

The process according to the invention is therefore characterized in that a mixture of the enantiomers of formula 1, stated on the formula sheet, is reacted in the form of the base with one of the enantiomers of a chiral acid, one of the two diastereoisomers thus obtained are separated by fractional crystallization and the base is transformed and, if desired, this is converted into a 1 8301739 -2-23154 / Vk / rab

* V

, addition salt with a pharmaceutically acceptable acid.

An enantiomer of formula 1 can also be obtained starting from a partially enriched base with one of the enantiomers, for example, obtained from the mother liquor from the crystallization of a mixture of the diastereoisomeric salts. The chiral acid used for the separation of such an enriched mixture is then its antipode which makes it impossible to obtain the said mixture.

The purity of the optical isomers of formula 1 can be checked, for example, by a gas phase (CPV) or liquid phase (CLHP) chromatography by a method described with respect to amino acids by B. Halpern in Handbook of Derivatives for Chromatography , biz. 457-476, edited by K. Blau and G.S. King, Heyden.

The process consists of condensing the isomer of Formula 1 with the chloroformate of (-) menthyl, of Formula 2, prepared according to the method described in the above literature to obtain the corresponding menthyl carbamate. This substance, when examined under CPV or CLHP chromatography, gives a single peak as it is present in a single enantiomer of formula 1 and of which two peaks are present when the separation of the two substances is not complete.

The invention is further illustrated by the following examples, illustrating the separation of the isomers of the compound of formula 1 and the determination of their purity.

Example I

(+) - 2,3,3a, 4,5,6-Hexahydro 1H-indole, 3,2,1-deJ {naphthyridine-1,5j and the methanesulfonate.

a) The formation of the diastereoisomeric salts with the (+) - 2,3-bis (4-methylbenzoyloxy) butadiene dicarboxylic acid.

34.41 g of 2,3,3a, 4,5,6-hexahydro 1H-indole £ 3.2, i-diaphthyridine are charged into a 2-liter conical flask equipped with a magnetic stirrer, a reflux condenser and a heating bath with oil. -1.5] as a racemic mixture in the form of an oily base, obtained according to Example 1 of patent application 8024717, dissolved in 250 ml of absolute ethanol. The mixture is stirred at ambient temperature and slowly adds 32.78 g (+) - 2,3-bis (4-methylbenzoyloxy) butanedicarboxylic acid dissolved in 250 ml absolute ethanol. In addition, an excess of 8301739 -3- 23154 / Vk / mb of liquid crystallization takes place just before the last addition. The mixture is then heated to reflux temperature, after which a further 200 ml of ethanol are added to obtain a complete solution of the crystals. Some insoluble crystals are removed by filtration, the filtrate is reheated and allowed to cool to ambient temperature. After allowing the mixture to stand for several hours, the crystals formed are filtered through a glass filter and dried under reduced pressure at 50 ° C. Thus, 43.56 g of white crystals are collected.

B) Recrystallization.

The crystals thus obtained are recrystallized several times in 95% ethanol. After each recrystallization, about 0.25 g of crystals are removed, the base of which is liberated with a mixture of dilute ammonia and chloroform, and the rotation is determined. After four recrystallizations, the rotation of the residual base is stable at a value of approximately = + 63.29 ° (o = 1 in MeOH).

The salt from which this base is liberated then has a rotational or rotating power of approximately ± 25p = + 84.51 ° (c = 1 in MeOH).

c) Methanesulfonate.

Into a 250 ml conical flask equipped with a magnetic stirrer, 5.78 g of the salt obtained under b) is charged with 100 ml of 10% ammonia and 100 ml of ethyl acetate. After stirring for a few minutes, the organic phase is separated, the aqueous phase is taken up again with 100 ml of ethyl acetate and the two obtained organic phases are combined, washed with water, dried over magnesium sulphate and evaporated in a rotary evaporate and dry under reduced pressure. Thus, the base is collected in the form of 2.96 g of a mixture of white crystals and an oil.

In a 250 ml flask equipped with a magnetic stirrer, this base is dissolved in 60 ml of ethyl ether and the equivalent amount of raethanesulfonic acid, i.e. 1.34 g, dissolved in 15 ml of absolute ethanol is added. Abundant crystallization forms immediately.

The mixture is stirred for an hour and a half at ambient temperature, then the crystals are filtered off through a glass filter and dried under reduced pressure at 50 ° C. Crystallization is then carried out in 60 ml of warm absolute ethanol and the mixture is left overnight at ambient temperature to obtain 3.03 g of methanesulfonate crystals after filtration and drying under reduced pressure, which are 8301739-4-23154 / Vk / mb melt at 222-224 ° C. The rotation ^ ° = + 21.58 ° (c »1 in MeOH).

The elemental analysis and the NMR and IR spectra confirm the structure of the compound.

d) Determination of purity.

140 mg (+) - 2,3,3a, 4,5,6-hexahydro 1H-indole ^ 3,2,1-de} phnaphthyridine are placed in a 100 ml flask equipped with a magnetic stirrer and an calcium chloride tube. -1.5 [] dissolved in 10 ml ethyl acetate with 66.7 mg (1 equivalent) triethylamine and the mixture is cooled in a bath consisting of ice and water. An equivalent of (-) - menthyl chloroformate dissolved in toluene, i.e. 1 ral -4 at 6.6.10 mol / ml, is then added and stirring is continued for 15 minutes at 0 ° C and then for 20 minutes at ambient temperature. The insolubles are filtered off and the organic phase is washed with water, then with an aqueous solution of 5% sodium bicarbonate and finally with water. The substance is then dried over magnesium sulfate and the mixture is evaporated on a rotary evaporator under reduced pressure. This gives 251 mg of a yellow oil, from which a solution of 0.1 mg / ml in ethyl acetate is prepared. The gas phase chromato-graphic determination of this solution gives a single peak diagram.

Example II

(-) - 2,3,3a, 4,5,6-Hexahydro 1H-indole [3,2,1-dê] {naphthyridine-1,5].

a) Releasing the base by starting from the mother liquor for the recrystallization of the dextrogiere isomer in the form of bis 2,3- (4-methylbenzoyloxy) butane dioate.

The filtrate from the first recrystallization obtained under Example 1b is dried in a rotary evaporator. 200 ml of 10% ammonia are then added, followed by 200 ml of ethyl acetate. The mixture is stirred for a few minutes and then filtered through a glass filter. The organic phase is separated, washed with water and dried over magnesium sulfate, and the mixture is evaporated in a rotary evaporator and then under reduced pressure. Thus, about 9.11 g of an orange oil are obtained.

b) Formation of the diastereoisomeric salts with (-) - bis-2,3- (4-methylbenzoyloxy) butanedicarboxylic acid.

In a 500 ml conical flask fitted with a magnetic stirrer and a cooler, placed in an oil bath, 9.08 g of oil, 8301739 -5-23154 / Vk / mb obtained according to Example 11a), dissolved in 65 ml of absolute ethanol, are added. ambient temperature, and within a period of 1 hour a solution of (-) - bis 2,3- (4-raethylbenzoyloxy) butanedicarboxylic acid in 65 ml of absolute ethanol is added. In addition, abundant crystallization takes place just before the end of the addition. The mixture is then slowly heated to reflux temperature and 140 ml of absolute ethanol are added, causing the crystals to dissolve completely. Some insoluble crystals are then removed by filtration, the mixture is reheated and left to stand at ambient temperature. After crystallization, the mixture is filtered through a glass filter and dried under reduced pressure at 50 ° C. 11.2 g of white crystals are thus collected.

c) Recrystallization.

The crystals thus obtained are recrystallized a few times in 95% ethanol. After each recrystallization, about 0.25 g of which the base is liberated with the aid of ammonia and chloroform are removed to determine the rotation. After five recrystallizations, the rotation of the base is stable at about tjJ = -63.38 ^ (c = 1.39 in MeOH). The salt then has a rotation of about Md = -89.21 ° 20 (c = 1 in MeOH).

Example III

(-) - 2,3,3a-4,5,6-hexahydro 1H-indole 3,2,1-d0-naphthyridine-1,5 ^ and its methanesulfonate, a) The formation of the diastereoisomeric salts with (-) - bis-25 2,3- (4-methylbenzoyloxy) butanedicarboxylic acid.

In an analogous manner as described in Example 1a), 34.41 g of an oily base dissolved in 250 ml of absolute ethanol are reacted with 32.78 g of (-) - bis 2,3- (4-methylbenzDyloxy) butanedicarboxylic acid dissolved in 250 ml of absolute ethanol in a 2 L conical flask under stirring with a magnetic stirrer, under reflux and heating with an oil bath. In addition, abundant crystallization takes place just before the end of the addition of the dicarboxylic acid, at ambient temperature. The mixture is then heated to reflux and 220 ml of absolute ethanol are added to the mixture to obtain a solution. Some insoluble crystals are removed by filtration. The filtrate is heated and allowed to stand at ambient temperature to allow crystallization to occur, then it is filtered through a glass filter and dried under reduced pressure at 50 ° C, 8301739-623154 / Vk / mb. This gives 35.47 g of crystals.

b) Recrystallization.

The procedure is as indicated in example Ic). After 5 four recrystallizations, the rotation of the residual base is 0 0 ^ = - 60.5 ° (cs1.15 in MeOH> and that of the salt is about C ° Gif ®7.90 (0 = 1 in M®0H) .

c) Methanesulfonate.

Into a 250 ml flask equipped with a magnetic stirrer, 1.15 g of enantiomer (oil) dissolved in 20 ml of ethyl ether are introduced and an equivalent amount or 0.52 g of methanesulfonic acid dissolved in 6 ml of ethanol is added quickly. Thereby crystals are formed, stirring is continued for 30 minutes before the crystals are air dried and dried under reduced pressure at 50 ° C. Recrystallization is then carried out in 19 ml of absolute ethanol. Finally, 1.12 g of methanesulfonate, which melts at 219-221 ° C, is collected.

The rotation is OQ ^ = -22.0 ° (c = 1 in MeOH).

The elemental analysis and the * NMR and IR spectra confirm the structure of the compound.

20 d) Determination of purity.

The procedure is as stated in example 1d). The resulting menthyl carbamate gives a single peak diagram by an ohromatographic determination in the gas phase.

The compounds of the invention are subjected to pharmacological tests conducted to demonstrate the importance of these compounds in the therapeutic field.

Hypobaric hypoxia.

Mice of the CD1 type are placed in an oxygen depleted atmosphere by applying a partial reduced pressure (190 mm mercury, corresponding to 5.25% oxygen).

The survival time of the animals is noted. This time is enhanced by agents that promote the uptake of oxygen into the tissue and especially cerebral oxygen uptake. The tested compounds are administered at multiple doses by intraperitoneal administration, 10 minutes before the experiment. The percent improvement in survival time over the values obtained in the comparative animals are calculated. The mean active dose that improves survival time by 100% (DA1QQ) is graphically determined 8301739% -7-2 315Wk / mb *>. The DA ^ value is 21-23 mg / kg. The DA ^ value is 7-10 rag / kg.

Ischaemia experiment, performed globally in mice.

The survival time of the animals subjected to the experiment is measured after they have been injected into the vein of the tail with 0.1 ml of a saturated magnesium chloride solution. The cardiac arrest that is brought about by this causes cerebral ischaemia. The "survival time" is the time between the injection of magnesium chloride and the last inspiratory movement of each mouse, which. 10 is considered to be the last indication of central nervous system function.

The survival time of the treated animals with compounds according to the invention, administered intraperitoneally 10 minutes before the injection with magnesium chloride, is compared with the survival time of the comparative animals to which only the carrier of the active substances has been administered.

The mice are studied in groups of 10, plotting the averages of the results of each group, based on which graph the "effective dose" is determined, expressed in 20 mg of active substance per kg of body weight, thereby extending survival time by 3 seconds (DE ^).

On the other hand, an improvement in survival time by 3 seconds is statistically significant and reproducible.

The DE 2 values of the compounds of the invention are 7 to 10 mg / kg.

The pharmacological study of the compounds of the invention indicates that they have anti-anoxic activity and that they can be used therapeutically to treat sleep problems, especially to combat problems due to cerebral damage veins and attributable to cerebral sclerosis from aging, as well as for the treatment of absence symptoms caused by trauma to the skull, for the treatment of metabolic brain diseases and for the treatment of depressive states.

Thus, the invention relates to the pharmacological compositions containing the compounds of the invention or their salts as active substances together with the appropriate excipients for administration, in particular for oral or parenteral administration. _ _ 8301739 Γ ** "i- -8- 23154 / Vk / mb

The administrations can be administered orally or parenterally, the daily dose ranging from 10 to 100 mg *

In summary, it can be stated that according to the invention enantiomers are obtained with formula 1, stated on the formula-5 sheet. These materials are separated by starting from a mixture by preparing their addition salts from an enantiomer and a chiral acid. The diastereoisomers thus obtained are separated by fractional crystallization, after which they are reconverted in the form of the base or the pharmaceutically acceptable salts.

8301739

Claims (8)

1. Process for separating the enantiomers of 2,3,3a, 4,5,6-hexahydro 1H-indole [3,2,1-de]] [naphthyridine-1,5 ^, characterized in that a mixture of the enantiomers of formula 1, stated on the formula sheet, in the form of the base reacts with one of the enantiomers of a chiral acid, one of the two diastereoisomeric salts thus obtained is separated by fractionate distillation and the base is converted and, if desired, the latter is converted into an addition salt with a pharmaceutically acceptable acid. Process according to claim 1, characterized in that the chiral acid used is bi3-2,3- (4-methylbenzoyloxy) butane dicarboxylic acid. 15 3 * Process according to claims 1 and 2, characterized in that the mixture of the enantiomers of formula 1 is the racemate. Process according to claims 1 and 2, characterized in that the enantiomer mixture of formula 1 is composed of the mother liquor with water of a previously performed separation. Process according to claims 1-4, characterized in that the salt formation is carried out with the chiral acid and the recrystallization in ethanol. 6. (+) - 2,3,3, a, 4,5,6-Hexahydro 1H-indole, 3,2,1-de *] [naphthyridine-1.53 and its addition salts with pharmaceutically acceptable acids. 7. (-) - 2,3,3 a, 4,5,6-Hexahydro 1H-indole 3,2,1-de] naphthyridine-1,5] and its addition salts with pharmaceutically acceptable acids. 8. Pharmaceutical composition, characterized in that it contains a compound mentioned in any one of claims 6 and 7. Eindhoven, May 1983 8301739 / * * #. "V% -10- 23154 / Vk / mb FORMULA SHEET ^^ 3 ΝΗ 0¾ 'CH, Cu · CiUCH, 830 1 73 9