NO128024B - - Google Patents

Description

Analogy method for the production of

serum lipid-lowering compounds.

The present invention relates to an analogue method for the production of serum lipid-lowering compounds.

In view of the continuing evidence that excessive serum lipid concentration is associated with basic pathogenic mechanisms and with symptoms of several diseases such as vascular diseases, diabetes mellitus and hyperthyroidism, lowering the serum lipid concentration is important in the treatment of such diseases.

According to the present invention, it has surprisingly been found that the compounds with the formula:

and therapeutically acceptable salts thereof, where A is -COOCHg- or -CH200C-, have valuable hypolipaemic activity. These compounds also have a very low toxicity and the biological test results show that side effects only occur to a very small extent and at relatively high doses.

The compounds with formula I are prepared according to the invention by reacting a pyridine derivative with the formula:

where A has the meaning given above, with a peroxy compound. Peroxy compounds suitable for use in this method include hydrogen peroxide, peralkanoic acids such as permauric acid and peracetic acid, aromatic peroxyacids such as perbenzoic acid and perphthalic acid, inorganic peroxyacids such as monopersulfuric acid and other organic and inorganic peroxide reagents. The preferred peroxy compound is hydrogen peroxide. The reaction is preferably carried out in an inert solvent such as chloroform, ethylene dichloride, acetic acid or propionic acid.

The pyridine derivatives which are used as starting materials in the above-mentioned method can be prepared using well-known methods.

In clinical applications, the compounds according to the present invention will normally be administered orally, rectally or by injection in the form of pharmaceutical preparations comprising the active ingredient in the form of the free base or a pharmaceutically acceptable salt thereof, e.g. the hydrochloride, together with a pharmaceutically acceptable carrier which may be a solid, semi-solid or liquid diluent or a swallowable capsule. Usually the active compound comprises between 0.1 and 95% by weight of the preparation, e.g. between 0.5 and 20$ for preparations intended for injection and between 0.1 and ^ 0% for preparations intended for oral administration.

The invention is illustrated by means of the following examples.

Example 1. Preparation of 3-Pvridinmethyl-2-(p-chlorophenoxy)-2-methylpropionate-N-oxide.. . 3-Pyridinmethyl-2-(p-chlorophenoxy)-2-methylpropionate (35.0 g) was mixed with 120 ml of acetic acid and 22 ml of 0% aqueous hydrogen peroxide and the solution heated at rf0°C for 16 hours. The solution was evaporated under reduced pressure, the residue mixed with water and aqueous sodium bicarbonate until pH 5 and the mixture evaporated again. The residue was soaked with 3 parts chloroform. The chloroform solution was evaporated and this gave 35 > 4 g of solid product.

It was dried over solid sodium hydroxide under reduced pressure and this gave 33» 3 S> m.p. 75-80°C. Recrystallization from a mixture of benzene and cyclohexane gave 24.60 g of the product, m.p. 88-91°C. Analysis:

Example 2. Preparation of 2-(p-chlorophenoxy)-2-methylpropyl-nicotinate-N-oxide. 2-(p-chlorophenoxy)-2-methylpropyl nicotinate (6.1 g). was dissolved in a mixture of y)% aqueous hydrogen peroxide (3.5 ml) °g acetic acid (20 ml) and the solution heated at 70°C for 17.5 hours. The solution was evaporated under reduced pressure, 10 ml added to the residue and the mixture evaporated again. 6.3 g of oil were obtained which crystallized by trituration with petroleum ether. Repeated recrystallization from a mixture of petroleum ether and ethyl acetate gave m.p. 96-98°C. "Analysis:

Biological experiments.

A. Toxicity.

The acute toxicity in mice of the compounds with

formula I after i.p. <p>g i.v. administration is given .as ..LD^q in grams per kg body weight, in table I. The compound 2-(p-chlorophenoxy)-2-methylpropyl-nicotinate-N-oxide is designated Ia in the table, , Likewise

is the compound 3-pyritiinmethyl-2-(p-chlorophenoxy)-2-methylpropionate- - N-oxide designated Ib,, and compound 2 is 3-Pyridinmethyl-2-(p-chlorophenoxy)-2-methylpropionate (known from French patent no.

1,498,459).... -~ ,.. ' , •

The toxicity of i.v. administration for compound Ia could not be determined due to poor solubility of this compound.

B. Effect on the triglyceride level in rat plasma.

Groups of male rats, strain Sprague-Dawley, with an average body weight of 150-200 g, were used. The analysis was carried out using the method described by L.A. Carlsson,

J. Atherosclerosis Res. 3, 334 (1963).

Each group consisted of six animals fed for 8 days a diet containing the compound to be investigated. The test compounds were added in an amount of 1 g compound per kilo-gram f6r. The animals were given water throughout the experiment. On the eighth day of the experimental period, the animals were killed and 5 ml of blood was taken from the aorta of each animal and collected in heparinized tubes. To obtain a sufficient amount of blood for the analysis, the blood from two animals was combined for each triglyceride test.

The result is shown in table II. Each value is the average of the experiments on three samples from each animal group. Each sample contains plasma from two animals.

C. Effect on the cholesterol level. i- rat plasma.- -

Analysis of the cholesterol level: in rat plasma. was performed-'<->' according to the Tschugaeff color reaction as described by Hanel and Dam,

Acta Chem. Scand., 9> ^77 (1955) after extraction of the plasma lipids with methanol/chloroform. The animals were treated in the same way as described under B above. The same strain of rats was used and the results are given in Table III analogously to what was done under B above. D. Effect of compound Ib on the level of free fatty acids in rat plasma.

The analysis of the level of free fatty acids in rat plasma was carried out using a combination of the methods described by Dole, Journal of Clinical Investigation 35 > '195 (1965) and Trout et al, Journal of Lipid Research 1, I99 (1960).

The animals were treated in the same way as described under B above. The same strain of rats was used and the results are shown in Table IV analogously to what was done under B above.

Although great caution must be exercised when evaluating results from biological experiments, the results shown in Tables I and II above seem to indicate that the compounds Ia and Ib of the present invention are capable of lowering the plasma level of triglycerides and the level of cholesterol in the experimental animals, and that compound Ib seems to have a lowering effect also on the plasma level of free fatty acids.

The previously known connection 2.seems mostly

to be equivalent to compound Ib in terms of serum lipid-lowering effect, but compound 2 has a toxicity that is 2-4 times greater than the corresponding oxide produced according to the present invention, i.e. compound Ib.

E. Peripheral vascular effects.

The peripheral vascular action of the compounds of formula I was measured and compared with the vascular action of nicotinic acid. The experiment was carried out by recording the skin temperature in the guinea pig's ear.

Male guinea pigs weighing 240-300 g were anesthetized by intraperitoneal injection of 1500 mg/kg body weight of urethane (6 ml of a 25% w/v solution). An iron-constantan thermocouple, type RM6, was placed with its thermocouple in contact with the skin surface of the ear. The skin temperature was recorded on a printer, type Z8. The recording accuracy was + 0.1°C.

The animals were injected intraperitoneally with the test compounds in doses of 150, 50 and 15 mg/kg body weight. The test compounds were administered as suspensions in 0.9% NaCl containing 2% methyl cellulose. The pH and tonicity of the solutions were adjusted to physiological levels by adding appropriate amounts of NaCl,

NaOH and H61.. The compounds were given in a volume of 8.0 ml/kg body weight. An increase in skin temperature of at least 0.3°C above the pre-injection temperature was considered a significant effect. The experiments were carried out at a room temperature of 22-23°C.

In 15 control animals it gave intraperitoneal administration

of 8.0 ml/kg body weight of a 0.9$ NaCl solution a small and gradual lowering of the ear temperature in all the animals and in the order of 0.3 + 0.2°C 60 minutes after the injection. In 15 animals injected with 8.0 ml/kg body weight of a 0.9% solution containing 2% methyl cellulose, there was a similar temperature reduction of 0.3 A 0.3°C. A rise in skin temperature of at least 0.3°C was therefore considered

an indication of vasodilatory action of the compound.

Nicotinic acid, which was used as a reference, produced a significant increase in temperature in doses of between 5 and 150 mg/kg body weight'. In most cases, the temperature rise began within 2 minutes after the injection and reached its peak value after -3-8 minutes. The temperature returned to the temperature range before the injection usually 10-20 minutes after the temperature rise began. As can be seen from Table I above, there was a fairly large inter-individual variation with regard to the size of the twist. No correlation was found between the maximum increase in skin temperature and the dose given.

The results from the experiment are shown in table V, where the influence of a single intraperitoneal injection of different doses of licotic acid, 2-(p-chlorophenoxy)-2-methylpropyl nicotinate N-oxide (in

-table denoted by "compound Ia") and 3~Pyridinmethyl-2-(p-chloro-'enoxy)-2-methylpropionate N-oxide (in the table denoted by "compound Ib") on the ear skin temperature of guinea pigs anesthetized with urethane, is granted.

This table shows that no effects on the skin temperature were recorded in animals injected with the test compounds Ia and Ib in doses of 15, 50 and 150 mg/kg body weight, while nicotinic acid caused a marked increase in the ear skin temperature. Compound 2, however, raises the skin temperature due to karut riding, which is an undesirable side effect.

Nicotinic acid is known to have a hypolipaemic effect

>g it is also used as a hypolipaemic agent. However, its peripheral rasodilator action reduces its therapeutic effect

application, because this compound even in small doses causes a frantic redness combined with skin irritation. As can be seen from

tables II, III and IV, the compounds according to the present invention have a hypolipaemic activity which is better or at least approximately equal to that of nicotinic acid, but the compounds do not show any peripheral vascular effects. These beneficial and unexpected effects combined with the extremely low toxicity of the compounds of the invention represent a major advance in this medical field.

Claims (1)

Analogous method for the preparation of serum lipid-lowering agents. compounds, with the formula: and therapeutically acceptable salts thereof, where A is -COOC^- or -CF^OOC-, characterized in that a compound of the formula: where A has the meaning stated above, is reacted with a peroxy compound to form the compound of formula I.