SAME

The invention relates to novel, therapeutically active 1-propene derivatives of the formula (I) ,

wherein

X and Y are independently from each other unsubstituted or halogen substituted phenyl or benzyl group, as well as their acid addition salts and pharmaceutical compositions containing these compounds.

Furthermore, the invention relates to a process for preparation of the above compounds and compositions. Surprisingly, it has been found that the compounds of formula (I) according to the invention show a very significant antiischaemic and antihypoxic effect exceeding those of known compounds possessing a similar action. Thus, they can be used to protect the organism from the hypoxia-induced harmful sequels or to diminish these sequels.

Accordingly, the invention relates also to a method of treatment, which comprises administering a thera¬ peutically effective amount of one or more compound(s) of formula (I) or a pharmaceutically acceptable acid addition salt thereof alone or in the form of a pharma¬ ceutical composition into the organism of a mammal (including human) to be treated, for achieving an anti¬ ischaemic and/or antihypoxic effect, i.e. for strengthen- ing the tolerance to hypoxic states.

According to the invention the novel compounds of formula (I), wherein X and Y are as defined above, as well as their acid addition salts are prepared by treating an 1-propanol derivative of formula (II),

wherein X and Y are as defined above, or an acid addition salt thereof with a dehydrating agent, then, if desired, converting a thus obtained base of formula (I) , wherein X and Y are as defined above, to an acid addition salt by treating the base with an acid; and/or, if desired, liberating a free base of formula (I), wherein X and Y are as defined above, from its acid addition salt by treating the salt with a base.

According to a preferred embodiment of the above process, a mixture of concentrated hydrochloric acid solution and glacial acetic acid is used as dehydrating agent and the reaction is carried out under boiling.

Alternatively, isopropenyl acetate may also be employed as dehydrating agent in an acidic medium. In this case the reaction is accomplished in an inert solvent such as dioxane.

Preferably, the reaction is carried out at the boiling point of the reaction mixture with reaction times of 30 to 120 minutes. The progress of the reaction can be followed by thin layer chro atography (TLC) . After cooling down the reaction mixture, the compound of formula (I) formed in the reaction can be isolated e.g. by filtration or, after evaporating the reaction mixture, by adding water and then carrying out filtration or extraction. If desired, the compounds of formula (I) isolated

may be purified by recrystallization from an organic solvent.

The compounds of formula (II) used as starting substances in the process according to the invention are similarly new 1-propanol derivatives and also possess a bio¬ logical activity. However, differently from that of the target compounds of the present invention, they show antipsychotic and/or anxiolytic effects.

The starting substances of formula (II) are synthetized by treating an oxo compound of formula (III) ,

wherein X and Y are as defined above, with a reducing agent in an organic solvent medium.

Complex metal hydrides, e.g. sodium borohydride, are preferred reducing agents. The reduction of the oxo derivatives of formula (III) by sodium borohydride is suitably carried out on the base form of the compound to be reduced, preferably in a lower alcohol or in a mixture of such an alcohol and acetonitrile at a temperature between 20 °C and 25 °C under stirring. The progress of the reaction may be followed by thin layer chromatography. The oxo compounds of formula (III) , which are also novel, can preferably be prepared in a manner known in se by reacting an oxo derivative of formula (IV) ,

wherein X is as defined above, and Z means halogen, with a piperazine derivative of formula (V) ,

wherein Y is as defined above, in an organic solvent in the presence of an acid binding agent.

The biological activity of the compounds of formula (I) was proven as described hereinafter. The experiments were carried out on male CFLP/LATI mice of 18 to 22 g body-weight in the tests l) , 5) and 6) ; on male mice of 24 to 26 g body-weight in the tests 2) and 3); and on spontaneously hypertensive male rats (SHR) of 200 g body-weight in the test 4) .

1) The anoxic asphyxia (AA) test

After starvation for 16 hours the mice were treated with oral doses of the substances to be tested. One hour following this treatment the animals were placed in air- tight glass bottles of 100 ml volume each and the survival time of the animals was measured. In the case of groups consisting of 10 animals each treated with the compounds, animals were considered to be protected, if their survival time was at least by 30 % longer than that of the average survival time of the placebo-treated group. The effective dose of 50 % (ED50 value) was calculated from the percentage of surviving animals by using probit analysis.

2) The hypobaric hypoxia (HH) test

After starvation for 16 hours and pretreatment of

1 hour the animals were placed in desiccators of 6 1 volume, each, then the pressure was decreased to 170 Hgmm

(22.66 kPa) during 20 seconds. The survival time was measured from this time until the last respiratory

movement of the animals. Animals were considered to be protected if their survival time was at least by 100 % longer than the average survival time of the control group.

3) The cytotoxic hypoxia (KCN) test

One hour following the pretreatment, each animal was treated with 5 mg intravenous (i.v.) dose of potassium cyanide. The survival time was measured from the time of administering potassium cyanide until the last respiratory movement. The protective effect was stated according to the evaluation described above for the anoxic asphyxia.

4) The hypobaric hypoxia test on SHR rats

One hour following the pretreatment the rats were placed by pairs in desiccators of 6 1 volume each. The pressure in the desiccator was decreased to 170 Hgmm (22.66 kPa) during 20 seconds and the survival time was measured from this point until the last respiratory movement. Animals were considered to be protected if their survival time was at least by 30 % longer than the average survival time of the control group. The effective dose of 50 % (ED5 ₀ value) with the pertaining fiducial limits of 95 % were calculated from the percentage of protected animals by using porbit analysis.

5) The anti-metrazole effect

One hour following the pretreatment the animals were treated with a subcutaneous (s.c.) dose of 125 mg/kg of etrazole (chemically 6,7,8,9-tetrahydro-lH-tetrazolo- [l,5-a]azepine) . The abolishment of tonic extensor con¬ vulsions and the survival were considered to be protective effect. The ED5 ₀ value was calculated from the percentage of protected animals by using probit analysis.

6) Protective effect against the maximum electro- shock

Electroshock was induced on mice by introducing a current of 20 mA for 0.2 second through corneal electrodes. The abolishment of tonic extensor convulsion under effect of treatment was considered to be protective effect. The ED50 value was calculated from the percentage of protected animals by using probit analysis.

The results of the above experiments are shown in Tables 1 and 2.

Table 1

Compound of Test Example No. 1) 2) 3) 4) Name of substance ED ₅₀ p.o. (mg/kg)

Compound of Example 1 92.0 32.0 21.0 7.1 Nimodipine >100 >100 85.0 8.0

Flunarizine >100 >100 58.6 >50

Table 2

Compound of Test Example No. 5) 6)

Name of substance ED50 P-°- (ng/fcg)

Compound of Example 1 7.1 41.8

Nimodipine 47.0 >60

Flunarizine 12.3 33.6

Nimodipine: chemically iεopropyl 2-methoxyethyl-l,4- -dihydro-2,6-dimethyl-4-(m-nitrophenyl) - -3,5-pyridinedicarboxylate

Flunarizine: chemically l-cinnamyl-4-[bis(4-fluoro- phenyl)methyl]piperazine

Based on the above experiments, the antihypoxic and cerebroprotective effects of the compounds of formula (I) are 2 to 4 times stronger than those of any of both reference drugs used for comparison in all models used for investigating the tolerance of healthy animals against a severe hypoxic insult with a fatal end. The antihypoxic effect is even more significant on spontaneously hypertensive (SH) animals [test No. 4)]. The anticonvulsive effect of compounds of formula (I) is also stronger than or about similar to such effect of the reference drugs. The therapeutical utilization of compounds of formula (I) may be taken into consideration in all clinical pictures where the mental and cognitive functions are injuried as a consequence of chronic disturbances of the cerebral metabolism and/or circula- tion.

When used therapeutically, the daily dose of compounds of formula (I) is 0.1 to 10 mg/kg of body- weight given in a single dose or in several subdoses through oral or parenteral route. The active compounds of formula (I) can be trans¬ formed to pharmaceutical compositions by mixing them with nontoxic inert solid or liquid carriers and/or additives commonly used in the therapy for enteral or parenteral administration. Useful carriers are inter alia e.g. water, gelatine, lactose, starch, pectin, magnesium stearate, talc or vegetable oils.

The active compounds may be formulated to the usual pharmaceutical compositions such as especially to solid forms, e.g. rounded or edged tablet, dragee, capsule (such as gelatine capsule) , pill, suppository and the like.

The amount of the solid active ingredient may be varied within broad limits, preferably it may be between 25 mg and 1 g in one tablet. Optionally, the compositions may contain the common pharmaceutical auxiliaries, e.g. preservatives. These compositions may be prepared by using common methods, e.g. sieving, mixing, granulating and optionally compressing the ingredients to obtain solid compositions. The compositions may be subjected to further usual operations of the pharmaceutical techno- logy, e.g. sterilization to obtain injectable composi¬ tions.

Active compounds with a structure similar to the compounds of formula (I) (e.g. flunarizine, used as reference drug in our experiments) are described in the DE patent No. 1,929,330. The effect of target compounds of the present invention exceeds that of flunarizine.

The invention is illustrated in detail by the following non-limiting Examples.

Example 1 Preparation of l-(l,l'-biphenyl-4-yl)-3-(4-benzyl- piperazin-1-yl)-l-propene dihydrochloride

1.6 g (4 mmol) of l-(l,l'-biphenyl-4-yl)-3-(4- -benzyl-piperazin-l-yl)-l-propanol in the mixture of 3 ml of concentrated hydrochloric acid solution and 3 ml of glacial acetic acid were boiled under reflux for 30 minutes while stirring. The progress of the reaction was followed by thin layer chromatography. After termination of the reaction, the mixture was cooled below 10 °C, the precipitate was filtered and washed twice with 5 ml of acetone each to obtain the title compound in a yield of 1.6 g (90.6 %) , m.p.: >280 °C.

Using the above process the following compounds were prepared:

1-(1,1'-biphenyl-4-yl)-3-[4-(4-fluorophenyl)pipe- razin-l-yl]-propene dihydrocloride; yield: 88.1 %,

m.p.: 244-248 °C;

1-[4-(4-chlorobenzyl)phenyl]-3-(4-phenylpiperazin- -l-yl)-l-propene dihydrochloride; yield: 72.1 %, m.p.: 112-116 °C; l-(l,l ^, -biphenyl-4-yl)-3-(4-phenylpiperazin-l-yl)-

-1-propene dihydrochloride; yield: 83.8 %, m.p.: 243-244 °C; l-[4-(4-chlorobenzyl)phenyl]-3-[4-(4-fluorophenyl)- piperazin-l-yl]-l-propene dihydrochloride; yield: 90.0 %, m.p.: 235-236 °C and 1-[4-(4-chlorobenzyl)phenyl]-3-(4-benzylpiperazin- -l-yl)-l-propene dihydrochloride; yield: 81.4 %, m.p.: 273-274 °C.

Preparation of starting substances and intermediates Example 2 Preparation of l-(l,l ^, -biphenyl-4-yl)-3-[4-(4- -fluorophenyl)piperazin-l-yl]-l-propanol The preparation of compounds of formula (II) is illustrated hereinafter on the example of the title compound. 0.033 mol of l-(l,l'-biphenyl-4-yl)-3-(4-phenyl- piperazin-l-yl)-l-propanone dihydrochloride was stirred for 5 minutes with the solution of 0.066 mol of sodium hydroxide in 80 ml of methanol and subsequently, 1.3 g of sodium borohydride were portionwise added at a tempera- ture of 10 °C during 20 minutes. The progress of the reaction was observed by thin layer chromatography. After termination of the reaction the mixture was poured into 500 ml of water, after stirring for 15 minutes the solid precipitate was filtered and twice washed with 20 ml of water each. After drying the title compound was obtained in a yield of 92.0 %, m.p.: 158-160 °C.

By following the above method the starting substances of formula (II) were prepared from the corresponding oxo derivatives of formula (III) .

Example 3

Preparation of l-(l,l ^« -biphenyl-4-yl)-3-(4-phenyl- piperazin-1-yl)-l-propanol

14.64 g (33 mmol) of l-(l,l'-biphenyl-4-yl)-3-(4- -phenylpiperazin-l-yl)-l-propanone dihydrochloride were stirred with 66 mmol of sodium hydroxide in 80 ml of methanol for 5 minutes, then 1.3 g of sodium borohydride were portionwise added at 10 °C during 20 minutes. The progress of the reaction was followed by thin layer chromatography. After termination of the reaction the mixture was poured into 500 ml of water, stirred for 15 minutes, then the solid precipitate was filtered, twice washed with 20 ml of water each and dried under an infrared lamp to obtain the title compound in a yield of 12.8 g (98 %), m.p.: 137-139 °C. Example 4

Preparation of l-(l,l'-biphenyl-4-yl)-3-(4-phenyl- piperazin-1-yl)-1-propanone dihydrochloride A mixture containing 2.05 g (8.3 mmol) of 4-(3- -chloropropionyl)biphenyl, 1.34 g (8.3 mmol) of N-phenyl- piperazine, 1.67 g (16 mmol) of triethylamine and 20 ml of toluene was boiled under reflux for 3 hours. After evaporating the reaction mixture the residue was thoroughly triturated with 40 ml of water. The solid precipitate was filtered, washed with water and dried. The dry product was dissolved in 30 ml of chloroform and acidified to pH 2 by adding ethanolic hydrogen chloride solution. After evaporation of the solution the residue was recrystallized from isopropanol to give the title compound in a yield of 2.68 g (73 %) , m.p.: 199-200 °C.

Preparation of pharmaceutical compositions Example 5

Preparation of tablets weighing 100 mg each with an active ingredient content of 10 mg each:

The mixture of

50.0 g of active ingredient,

285.0 g of lactose

100.0 g of potato starch 2.5 g of sodium dodecyl sulfate

5.0 g of polyvinylpyrrolidone (Kollidon K 90 ^R )

50.0 g of microcrystalline cellulose (Avicel ^R ) and

7.5 g of vegetable oil (Sterotex ^R ) was wet-granulated and compressed in the common way to tablets. Each tablet weighed 100 mg and contained 10 mg of active ingredient. Example 6

Preparation of dragees weighing 125 mg each with an active ingredient content of 10 mg each: The tablets prepared as described in the Example 5 were coated in a known manner with a layer consisting of sugar and talc. The dragees obtained were polished with a mixture of bee wax and carnauba wax. Example 7 Preparation of capsules containing 20 mg of active ingredient each:

40.0 g of active ingredient 12.0 g of sodium lauryl sulfate, 102.0 g of lactose 102.0 g of potato starch,

2.4 g of magnesium stearate and

1.6 g of colloidal silicon dioxide were intimately mixed together and the mixture obtained was filled into hard gelatine capsules. Each capsule contained 20 mg of active ingredient.