Piperazines

The present invention concerns new piperazine derivatives and homologs thereof of formula ##STR3## wherein

n is equal to 2 or 3 and m to 1, 2 or 3;

X represents hydrogen or a methyl group;

R represents hydrogen or a C.sub.1 to C.sub.6 lower alkyl group or a C.sub.1 to C.sub.3 hydroxyalkyl group; and

R.sub.1 is a cyclohexyl group of formula ##STR4## wherein R.sub.2 is hydrogen or a C.sub.1 to C.sub.6 lower alkyl group.

These compounds possess anti-ulcer and anti-secretion properties and are entirely free from anticholinergic activity.

These compounds can be prepared by first reacting an amine of formula R.sub.1 --NH.sub.2 with an acyl chloride derivative (e.g. chloracetyl chloride, chloropropionyl chloride or chlorobutyryl chloride) and, thereafter, condensing the obtained product with piperazine or its derivatives. For instance, the following reaction can be performed: ##STR5##

In such instance, one mole of N-(2-chloracetyl)-cyclohexylamine can be reacted with two moles of piperazine and two moles of HCl in water solution.

The reaction works also when 1 mole of piperazine dihydrochloride is used.

It is also possible to use an excess of piperazine in water in ratios of 1:3 to 1:4, however in such case the process is more expensive. On the other hand, the condensation can be carried out in organic solvents, e.g. chloroform or benzene.

The new compounds are also active in the form of their salts with organic or mineral acids, such as, for instance, hydrochlorides, sulfates, phosphates, maleates, succinates and tartrates.

The following is a typical example for preparing the new compounds of the present invention:

Anhydrous piperazine (178.28 g; 2 moles) was dissolved in 1000 ml distilled water. Then HCl 37% (166.6 ml) was added dropwise to provide 2 moles of piperazine mono-hydrochloride. Then N-(chloracetyl)-cyclohexylamine (175.66 g) was added to the above solution of the hydrochloride. The temperature rose to 100.degree. C. and the reaction was completed by refluxing for two hours.

After cooling, the reaction mixture was made alkaline with a 35% NaOH solution and thereafter extracted with chloroform.

The chloroform extract was washed with water, dried with anhydrous Na.sub.2 SO.sub.4, filtered and evaporated.

The residue was washed with petroleum ether, drained and dried.

The obtained 1-piperazinyl-4-methylene carbonylcyclohexylamine (or N-[1-piperazinylacetyl]-cyclohexylamine), code C/63, was distilled under reduced pressure (b.p. 190.degree. C./0.5 mm); m.p. 111.degree.-112.degree.; yield 65% of theory.

The following compounds have been prepared in the same or analogous manner: ##STR6##

The following table contains the results of pharmacological tests with these compounds. The abbreviations used are iv=intravenous, id=intraduodenal, po=per os, antisecr. act.=antisecretory activity, antiulc. act.=antiulcer activity, PhB/H=phenylbutazon/histamin, all amounts being in mg/kg.

The tests have been made according to the following known methods:

Activity on the gastric secretion (according to Shay, Gastroenterology 5, 43 (1945)).

Phenylbutazone-histamine ulcer (according to Carminati Coll., Boll. Chim. Pharm. 112, 45 (1973)).

The present invention also concerns pharmaceutical compositions which may contain, according to the invention, the new compounds in admixtures with solid or liquid pharmaceutical diluents or carriers and, as desired, in admixtures with other active ingredients or binders.

As examples of pharmaceutical packages, one can mention 50 or 100 mg capsules and ampoules of one of the above compounds. The daily dose will be 1 to 2 ampoules or 2 to 4 capsules.