GB1585832A - Process for the preparation of pinocarveol and therapeutical use thereof - Google Patents

Description

PATENT SPECIFICATION

( 11) 1 585 832 ( 21) Application No 1504/80 ( 22) Filed 25 May 1977 ( 1 ( 62) Divided out of No 1585831 ( 31) Convention Application No 7042/76 ( 32) Filed 3 Jun 1976 in ( 33) Switzerland (CH)

( 44) Complete Specification Published 11 Mar 1981

C 07 C 29/00 A 61 K 31/045 x at Acceptance 121 X 200 225 227 22 Y 30 Y 360 36 Y 43 X 502 50 Y 623 662 802 FA WN ( 54) PROCESS FOR THE PREPARATION OF PINOCARVEOL AND THERAPEUTICAL USE THEREOF ( 71) I, ENRICO CORVI MORA, an Italian Citizen of Via Scalabrini 49, 29100 Piacenza, Italy, do hereby declare the invention, for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to the preparation of pinocarveol starting from oxidized terpene mixtures, obtained by the oxidation of a mixture of a-pinene and f 3-pinene, and its use in the therapeutics of bronchopneumonial diseases.

In the Swiss Patent Specification No.

542,163 of the same applicants hereof, a method is described for the preparation of terpene fractions which are useful in the treatment of bronchopneumonial diseases, said method being based on the oxidation of mixtures which predominantly contain alpha-pinene More particularly with the method according to the above mentioned Swiss Patent, two terpene fractions are obtained, which distill, respectively, in the temperature ranges of from 40 C to 60 C and of from 65 C to 103 C.

Our Copending Patent Application No.

22089/77 (Serial No 1585831) relates to the additional treatment of oxidation mixtures to give verbenone and myrtenal.

The present invention provides a process for preparing pinocarveol from a reaction mixturre resulting from the oxidation of a mixture of a-pinene and l 3-pinene which process comprises treating the reaction mixture with aluminium isopropoxide forming the bisulphite adducts of carbonyl"containing compounds in the reaction mixture extracting in water the bisulphite adducts to leave a residue and fractionally distilling the residue under a reduced pressure of 2 () mm Hg to isolate the pinocarveol at 1000 to 1060 C.

The pinocarveol is formed by the opening of the oxiran ring of a-pinene epoxide which is present in the oxidation mixture The opening of the oxiran ring is carried out using aluminium isopropoxide After this ring opening reaction, carbonyl-containing compounds such as myrtenal and verbenone, which are also present in the oxidation mixture, are removed by forming their bisulphite adducts which can be extracted in water.

The pinocarveol is then isolated by subjecting the residue obtained after the carbonyl-containing compounds have been removed to fractional distillation under reduced pressure at 20 millimeters of mercury.

Generally it is preferred to include the additional step of isolating verbenone and myrtenal from the aqueous extract by fractional distillation under a reduced pressure of 20 mm Hg at 90-95 C for myrtenal and 110-113 C for verbenone.

As regards the therapeutical use of the compound obtained by the process according to the present invention, the therapeutical use of the terpene fractions disclosed in the Swiss Patent 542,163 is already known, and more particularly the use of the fraction which distills in the 65 C to 103 C range (to be indicated hereinafter as the "fraction 2 ").

The balsamic and analeptic actions of such fraction 2 are alreadv known, the therapeutical use of such fraction being just due to such actions.

In addition to the uncertainty from a scientific standpoint as to the exact identification of the active principles which are responsible for the therepeutical activity of pharmaceutical compositions based on such fraction 2, the drawback is apparent from an industrial viewpoint, of working on a mixture of compounds having a composition which is changeable even within a certain range In addition, the fact is worth noting that the pharmaceutical composition coneq me ( 51) INT CL 3 ( 52) Index C 2 C 362 Y 1 p 21 585 832 taining the fraction 2 has a general indication as a balsamic, along with a few side activities, without any possibility being afforded of exalting the one of these activities preferably over the others, or of improving the general activity.

It has now been found that pinocarveol possesses, in additon to the known balsamic and analeptic, actions appreciable bronchodilating, anti-phlogistic, anti-exudative and anti-aggregative actions.

The demonstration of the pharmacological activity of pinocarveol is based on the following parameters:

1 Acute toxicity 2 Action on the bronchial muscles 3 Action on the inflammatory process 4 Action on haemolysis Action on the thrombocyte aggregation 6 Antibacterial action.

PHARMACOLOGICAL PROPERTIES OF PINOCARVEOL 1 Acute toxicity The LD 5 ( as determined according to the method by Litchfield and Wilcoxon (J.

Pharm Exp Ther 96 98 1949) bv administering pinocarveol intravenously to groups of 10 rats per dosage was equal to 140 milligrams per kilogram.

2 Bronchodilating activity Pinocarveol has exhibited, both in vitro and in vivo a fair bronchodilating action.

a ill vitro On the Guinea-pig trachea isolated according to the technique by Costantine (J.

Pharm Parmacol, 17 384 1965) pinocarveol determines the relaxation of the smooth tracheal muscles at the concentration of 125-2 000 micrograms/ml with an intensity which is statistically higher thari that of sobrerol and which can be compared to that of Fraction 2.

b in vivo Pinocarveol perfused intravenously in rabbits at the dosage of 2 5 milligrams per kilogram and per minute exhibits the experimental bronchspasm induced bv histamine ( 100 micrograms per kilogram intravenouslv) in a manner which is statisticallv higher than those of Fraction 2 and of sobrerol.

3 Anti-inflaninatori activitv In albino rats of the COBS (Charles River) stock pinocarveol administered intravenouslv at the dosage of 3 () millierams per kg inhibits the experimental paw oedema from injection of carrageenin (Winter.

C.A et al Proc Soc Exp Biol Med 111 544 1962) to a degree which is more intense than those of Fraction 2 and of sobrerol.

4 Anti-haemolvtic activity, in vitro Pinocarveol at concentrations of from 20 to 200 micrograms/ml protects the red blood cells of rats from the haemolysis caused by capillary-active agents (Tween 80 "Tween" is a Registered Trade Mark) with an Effective Concentration 50 % (EC 50) of 132 29 micrograms/ml (Fiducial limits 95 % = 111 5-153 04).

Anti-aggregative activity Pinocarveol at concentrations of from 160 to 1 280 micrograms/ml inhibits, in vitro, the thrombocyte aggregation due to ADP evaluated according to the method by Born and Cross ( J Physiol, London, 168, 178, 1963) to a degree which exceeds that of the terpenes of the Fraction 2 and' that of sobrerol.

6 Anti-bacterial activity Pinocarveol is endowed with a poor antibacterial activity both on'Gram-positive and Gram-negative germs with a MIC (Mini-' mum Inhibiting Concentration) of 800 micrograms/ml on Staphylococcus aureus and Escherichia coli and is thus more active than sobrerol and as active as Fraction 2.

Summing up, the compound pinocarveol has proven to possess a pronounced antiinflammatory action by virtue of which it distinguishes in a 'statistically significant manner from the other medicinal substances such as the mixture of Fraction 2 of the Swiss Patent aforementioned and sobrerol.

Pinocarveol possesses a poor bronchodi-' lating action and is also endowed with a pronounced anti-haemolytic activity by virtue of which it is possible to attribute to such compound a stabilizing action at the cellular membrane level.

Pinocarveol displays a poor antibacterial action and also exhibits a conspicuous antiaggregative action.

On account of its particular propertie s, pinocarveol can be the active ingredient of a medicament which is particularly suitable for the treatment of bronchopneumonial diseases which aire accompanied by a strong inflammatory pattern of the respiratory channels.

The dosages to be recommended for this therapeutic application are from 10 to 100 millierams daily.

The pharmaceutical compositions according to the present invention comprising pinocarveol together with a pharmaceuticallv acceptable carrier or diluent can be presented in the form of preparations for oral administration normal or delayed action such as soft capsules or injectable ampoules suppositories, sprays in various I3 1 585 832 3 solution forms, ointments and balms with the usual media, fillers and so on as conventionally used in the pharmaceutical art, both as individual components and in association with medicaments indicated in the diseases referred to above, that is, antibiotics, antibacterial substances, chemio-therapeutic substances, sulfonamide drugs, antiinflammatory drugs, cortisone preparations and analgesics.

The following Example is intended to illustrate, without limitation, the preparation of pinocarveol according to the present invention.

EXAMPLE a Conversion of alpha-pinene epoxide into pinocarveol grams of the terpene mixture of Fraction 2 of the Swiss Patent No 542,163, 10-15 % of which comprises alpha-pinene expoxide, whereas 20-30 % consists of compounds having a carbonyl moiety, and 50% consists of compounds having an alcoholic moiety (verbenol, pinocarveol and myrtenol), are dissolved in 60 mls of anhydrous toluene To the solution is added aluminum isopropoxide (about 2-3 grams) and the mixture is boiled during 10 minutes.

The mixture is carefully cooled and slowly acidified by cautiously adding diluted sulfuric acid, while still keeping at a temperature of O C or below The phases are separated, the liquors are exhausted with toluene, the organic solutions combined, washed with water and dried over anhydrous Na 25 04.

Filtration is carried out and evaporation at C under reduced pressure is effected until a solid residue is obtained There are obtained about 60 grams of a raw product which is exempt from epoxide and is enriched with compounds having an alcoholic function (pinocarveol, verbenol and myrtenol).

b Separation of the carbonyl compounds The residue which has been obtained from the previous stage is taken up with 300 mls of diethyl ether and the resultant solution is subjected to vigorous stirring with a mixture formed by 60 grams of Na H 503, 36 grams of Na HCO 3 and 1,000 mls of water, such treatment being carried out during 20 hours at room temperature The mixture is transferred into a separatory funnel and the phases are separated The aqueous phase contains myrtenal and verbenone in the form of soluble bisulfite adducts from which they can be recovered in the form of pure products by working according to the process of our copending British Patent Application No 22089/77 (Serial No.

1585831 The organic phase, which contains the alcoholic compounds is washed to neutrality with water dried over Na 25 04.

filtered and evaporated to dryness under reduced pressure There are obtained 40-50 grams of a residue which is predominantly composed by pinocarveol, verbenol and myrtenol.

c Isolation of pure pinocarveol The residue coming from the previous stage is subjected to fractional distillation under vacuum, at 20 millimeters of mercury, using a reflux column filled with nickel shavings The distillation is carried out slowly ( 5-6 mls/hour) by maintaining a reflux of about 40:1 durinfig the entire run.

The fraction which distills at 100 C-106 C under 20 millimeters of mercury and which is strongly enriched with pinocarveol, is collected and subjected to redistillation under the same conditions There are obtained 15-18 grams approx of 95 %-98 % pure pinocarveol which has the following physico-chemical specifications:

b.point: 103-104 C under 20 mm Hg; n 20 = 1 4988; dc O = 0 98 Infrared analysis: characteristic bands of terminal double bond at 6 00 microns and at 11.20 microns.

Claims (2)

WHAT I CLAIM IS:-

1.A process for preparing pinocarveol from a reaction mixture resulting from the oxidation of a mixture of a-pinene and l 3-pinene which process comprises treating the reaction mixture with aluminium isopropoxide, forming the bisulphite adducts of carbonyl-containing compounds in the reaction mixture, extracting in water the bisulphite adducts to leave a residue, and fractionally distilling the residue under a reduced pressure of 20 mm Hg to isolate the pinocarveol at 100 -106 C.

2 A process as claimed in claim 1 including the additional step isolating verbenone and myrtenal from the aqueous extract by fractional distillation under a reduced pressure of 20 mm Hg at 90 -95 C for myrtenal and 110 -113 C for verbenone.

3 A process as claimed in claim 1 substantially as hereinbefore described with reference to the Example.

4 Pinocarveol whenever prepared by the process claimed in either claim 1 or claim

2.

A pharmaceutical composition comprising, as an active ingredient pinocarveol prepared by the process claimed in claim 1, together with a pharmaceutically-acceptable carrier or diluent.

1 '585 832 4 1 585 832 4 6 Verbenone and Myrtenal whenever obtained according to the process claimed in claim 2.

STEVENS, HEWLETT & PERKINS, Chartered Patent Agents, 5, Quality Court, Chancery Lane, London, W C 2.

Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey 1981.

Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.