GB1585831A

GB1585831A - Process for the preparation of verbenone and myrtenal and therapeutical uses thereof

Info

Publication number: GB1585831A
Application number: GB22089/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-06-03
Filing date: 1977-05-25
Publication date: 1981-03-11
Also published as: GB1585832A; PT66619A; AU519521B2; FI771765A; AU2573277A; FR2416878A1; IT1074511B; JPS52151156A; AR214200A1; CA1099214A; HU178205B; SU816396A3; ATA394077A; PL116550B1; PL198600A1; ZA773345B; ES459425A1; FR2479804A1; SE8105687L; PT66619B

Abstract

When a mixture resulting from the oxidation of alpha - and ss-pinene is subjected to an oxidising treatment, it is possible to isolate verbenone, myrtenal and pinocarveol from the reaction product by fractional distillation. These compounds have therapeutic properties in bronchopulmonary diseases.

Description

(54) PROCESS FOR THE PREPARATION OF VERBENONE AND MYRTENAL AND THERAPEUTICAL USES 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 verbenone and myrtenal starting from oxidized terpene mixtures, obtained by the oxidation of a mixture of a-pinene and p-pinene, and their uses in the therapeutics of bronchopneumonial diseases.

The preparation of verbenone and myrtenal starting from alpha-pinene by oxidizing self-catalysis in the presence of salts of chromium, cobalt, and others has been repeatedly described with yields of from 15 % to 20 %. One of the reasons for the low reaction yields is the formation of side-products of the homolytic reaction such as verbenols and myrtenols, these latter being alcohols which cannot be further oxidized to the ketones in the specific reaction medium.

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 600C and of from 65"C to 1030C.

It has now been found that such oxidation mixtures can be subjected to a further oxidation treatment with chromium trioxide in sulfuric acid.

The present invention provides a process for preparing verbenone and myrtenal from a reaction mixture resulting from the oxidation of a mixture of a-pinene and ss-pinene which process comprises oxidizing the reaction mixture with chromium trioxide in sulphuric acid, forming the bisulphite adducts of the verbenone and myretanal produced, extracting the bisulphite adducts in water and fractionally distilling the extract under a reduced pressure of 20 mmHg to isolate the myrtenal at 90"-95"C and the verbenone at 1100-113"C.

It has been found, in fact, that in the case of verbenone and myrtenal, in the oxidizing mixtures of the Swiss Patent aforementioned, the oxidative method goes on with a total disappearance of the alcohols and a formation of carbonyl compounds (ketones and aldehydes). Upon treatment with chromium trioxide in suluric acid an isolation of the as-obtained ketone bodies is accomplished by means of the formation of a bisulfite complex and fractional distillation.

As regards the therapeutical use of the compounds obtained with the method 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-103"C range (to be indicated hereinafter as the "fraction 2").

The balsamic and analeptic actions of such fraction 2 are already 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 therapeutical 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 pharmacuetical composition containing the fraction 2 has a general indication as a balsamic, along with a few side activities, but there is no possibility of brining out one of these activities in favour of any of the others, or of improving the general activity.

It has now been found that verbenone and myrtenal possess in addition to the known balsamic and analeptic actions, appreciable bronchodilating, antiphlogistic, antiexudative and antiaggregative actions.

The demonstration of the pharmacological activity of verbenone and myrtanal 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 5. Action on the thrombocyte aggregation 6. Antibacterial action.

In all these tests, the activities of the verbenone and myrtenal have been compared, with those of the fraction 2 as defined above and therapeutical preparations based on terpene alcohols, more particularly sobrerol.

The individual compounds the subject of the present invention will be now considered: A - Verbenone 1. Acute Toxicity TABLE 1 reports the LD50 (and the fiducial limits 95No) as determined according to the Litchfield and Wilcoxon method (J. Pharmacol. Exp. Ther., 96, 99, 1949), by administering verbenone both intraperitoneally (i.p.) and orally (p.o.) to groups of 10 mice and 6 rabbits per dose.

TABLE 1 admini LD somilli- Gleason stration grams per classi Compound Animals Sex route kg/b.w. fication Mice Male i.p. 361 Poor (337-385) Female 325 (308-343) VERBENONE Mice Male p.o. 1410 Slight (1165-1706) Female 1530 (1124-1912) Rabbits Male i.p. 310 Poor (250-384) Female 232 (197-274) Rabbits Male p.o. 790 Poor (608-1027) Female 655 (570-753) On the basis of these data the verbenone appears a well tolerated compound, since its toxicity is of the slight or poor magnitude according to the Gleason classification, as related to the animal species and the administration route.

2. Bronchodilating activity Verbenone has exhibited, both in vitro and in vivo, a pronounced bronchodilating activity, by virtue of which it is distinguished in a statistically significant way both over the other medicinal substances present in the fraction 2 of the Swiss Patent 542,163 and over the reference terpene, i.e. sobrerol.

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

Pharmacol., 17 384, 1965). verbenone brings about the relaxation of the smooth tracheal muscles at the concentration of 125 to 2,000 micrograms per milliliter with an intensity which is significantly higher than that of the terpenes of the fraction 2 and also than that of sobrerol (TABLE 2). In addition at concentrations in the range of from 10- 3M to 5.10-3M, it inhibits the histamine-induced contractions of the isolated Guinea-pig trachea (Histamine 10-5M, see TABLE 3).

TABLE 2 Percentages of relaxation (average + standard deviation of 4 preparations) of the isolated Guinea-pig trachea as brought about by concentrations of 125, 500 and 2,000 micrograms per milliliter.

Preparations Compound No. 125 CLg/ml 500g/ml 2,000 ,uvg/ml VERBENONE ave. 26.25 61.25 71.37 4 std.dev. 2.39 2.39 1.15 FRACTION 2 ave. 13.5 33.75 52.25 4 std.dev. 1.70 1.49 2.95 SORBEROL ave. 1.87 5.62 20.75 4 std.dev. 1.19 2.13 1.49 TABLE 3 Verbenone percentages of inhibition of the histamatic spasm due to relaxation of the smooth tracheal muscles (average + standard deviation of 4 preparations).

Concentration 1O-3M 5.10-3M Average 29.2 96.8 Standard Deviation 5.1 16.6 b - in vivo Verbenone injected intravenously in anesthesized dogs at dosages of from 0.6 milligrams per kilogram body weight to 4.8 mgs/kg/b.w. produces a pronounced reduction of the lung resistances as determined according to the technique by Diamond (Arch. Int. Pharmacodyn., 168, 239 1967) see TABLE 4). In addition, verbenone perfused intravenously in rabbits at the dose unit of 2.5 mls per kilogram b.w. per minute, inhibits the histamine-induced experimental bronchospam (histamine 100 micrograms per kilogram b.w. intravenously) to a degree which is statistically higher than that of the terpenes of the fraction 2 and also than that of sobrerol (TABLE 5).

TABLE 4 VERBENONE - Percentage reductions of the Lung Resistance by intravenous administra tion to dogs (Average + Standard deviation for 4 animals).

Dosage mgs/kg b.w. 0.6 1.2 2.4 4.8 Average 7.175 10.85 22.225 30.6 Standard deviation 6.786 7.7 18.636 13.507 TABLE 5 Percentages of the histamine-induced bronchospasm by intravenous perfusion in rabbits (average of 4 animals + standard deviation).

Perfusion Times Compound 15 30 60 minutes minutes minutes average 36.25 46.27 73.32 VERBENONE std.dev. 1.65 9.00 7.17 average 16.30 24.20 38.92 FRACTION 2 std.dev. 3.62 4.39 3.67 average 2.15 1.15 3.97 SORBREROL std.dev. 4.30 6.39 8.73 3. Anti-inflammatory activity In albino rats of the COBS (Charles River) stock, verbenone as administered intraperitoneally at the dosage of 30 milligrams per kilogram b.w. inhibits the experimental oedema in the paw as induced by carrageenin (Winter, C.A. et al., Proc. Soc. Exp. Biol. Med.

111, 544, 1962) both in normal rats and in suprarenalectomized rats to a degree which is, from the statistical standpoint, significantly improved over those of the fraction 2 and of sobrerol (TABLE 6).

When administered intraperitoneally in rats at the dosages of 36 to 120 milligrams per kilogram b.w., verbenone displays an intense antiexudative activity in the experimental.

turpentine-induced pleuritis (Hurley, J.V. et al., J. Path., 91, 575, 1966) to a degree which can be compared to that of aspirin (TABLE 7).

TABLE 6 Anti-inflammatory activity on the carrageenin-induced oedema in rats.

% inhibition of plantar Dosage milli- oedema, as after 4 hrs.

grams/kg b. w. from administration intraperitone- (ave. + Std. dev. on 6 Compound ally animals) VERBENONE 30 29 FRACTION 2 30 21 SOBREROL 30 11 4. Haemolytic acitivity, in vitro Verbenone protects in vitro the red blood cells of rats from the haemolysis as induced by capillary-active-agents (Tween 80 -'Tween' is a registered Trade Mark) with an effective concentration 50% (EC 50) of 639.5 micrograms per kg b.w. (fiducial limits 95%: : 518.0- 760.11).

5. Antiaggregative activity, in vitro Verbenone. at concentrations of from 160 to 1.280 micrograms/milliliter inhibits the thrombocyte aggregation from ADP in vitro. evaluated according to the method by Born and Cross (J. Physiol., London, 168, 178, 1963) to a degree which is higher than that of the terpenes of the Fraction 2 and of sobrerol (TABLE 8).

TABLE 7 Activity of Verbenone on the Turpentine-Induced Pleuritis in Rats.

In trap eritoneal Exudate + Std. Inhibition Signify administration mls Dev. % cativity P Controls 1.97 0.24 (solvent) Aspirin 1.30 0.13 34 % 0.01 (100 mgs/kg) Verbenone 1.23 0.24 37.6% 0.01 (36 mgs/kg) Verbenone 0.97 0.22 50.1% 0.01 (120 mgs/kg) TABLE 8 Thrombocyte aggregation inhibition percentage (average of repeated tests).

Final Concentrations % Inhibition Control 0 Verbenone 1280 ,u g/ml 100 640 " 44 320 " 6 160 "g 0 Control 0 Sobrerol 4000 CLg/ml 32 2000 " 24 1500 " 12 1000 " 4 Control 0 Fraction 2 1280 ,ug/ml 70 1016 " 18 806 " 14 640 " 0 6. Antibacterial activity Verbenone possesses a poor antibacterial activity on the Gram-positive and Gramnegative germs with a MIC (Minimum Inhibiting Concentration) of 800 micrograms/ml on Straphlococcus aureus and Escherichia coli (TABLE 9) and is as active as Fraction 2 and more active than sobrerol.

TABLE 9 Minimum Inhibiting Concentrations (MIC) in micrograms per milliter.

Microorganism Staphylococcus Escherichia Compound aureus coli Verbenone 800 800 Fraction 2 800 800 Sobrerol humming up, the compound has proven to possess a pronounced bronchodilating action, by virtue of which it distinguishes in a statistically significant manner both over the medicaments present in Fraction 2 of Swiss Patent 542,163 and the reference terpene (sobrerol).

On account of these particular properties, verbenone is effective as the active ingredient of a pharmacuetical preparation which is especially adapted for the treatment of bronchopneumonial diseases which are accompanied by an obstruction of the respiratory channels due to inflammation and infectious causative agents. The dosage envisaged for therapeutical applications is from 10 to 100 milligrams daily.

B- Myrtenal 1. Acute toxicity The LDS, as determined according to the method by Litchfield and Wilcoxon (J. Pharmacol. Exp. Ther., 96, 99, 1949) by administering the myrtenal intravenously to groups of 10 mice was 170 milligrams per kilogram b.w.

2. Bronchodilatory activity Myrtenal has shown, both in vitro and in vivo, a fair bronchodilating activity.

a - in vitro On the isolated Guinea-pig trachea according to the technique by Costatine (J. Pharm.

Pharmacol. 17. 384. 1965). myrtenal determines the relaxation of the tracheal smooth muscles at the concentration of 125-2000 micrograms/ml with an intensity which is statisti cally higher than that of the Fraction 2 and that of sobrerol (Table 10).

TABLE 10 125 500 2,000 Preparations micro- micro- micro Compound No. gr/ml gr/ml gr/ml ave. 7.5 47.5 62.5 MYRTENAL 4 std.dev. 5.0 15.0 20.7 ave. 13.5 33.75 52.25 FRACTION 2 4 std.dev. 1.70 1.49 2.95 ave. 1.87 5.62 20.75 SOBREROL 4 std.dev. 1.19 2.13 1.49 b - in vivo Myrtenal perfused intravenously in rabbits at the dosage of 2.5 milliliters per kg b.w. per minute inhibits the experimental histamine-induced bronchospasm (histamine 100 micrograms/ kg b.w. intravenously) in a manner which is statistically higher than that of sobrerol and slightly lower than that of Fraction 2 (Table 11).

TABLE 11 Percentages of inhibition of the histamine-induced bronchospasm by intravenous perfusion in rabbits (average on 4 animals I standard deviation).

Perfusion times 15 mins. 30 mins. 60 mins.

Compound ave. 25.4 20.4 28.8 MYRTENAL std.dev. 10.4 16.2 13.5 ave. 16.30 24.20 38.92 FRACTION 2 std.dev. 3.62 4.39 3.67 ave. 2.15 1.15 3.97 SOBREROL std.dev. 4.30 6.39 8.73 3. Anti-inflammatory activity In albino rats of the COBS (Charles River) stock. myrtenal as administered intraperitoneally at the dosage of 30 milligrams per kg b.w. inhibits the experimental paw oedema from injection of carrageenin (Winter. A.C. et al.. Proc.Soc. Exp. Biol. Med. 111. 544. 1962) to a degree which is more intense than that of Fraction 2 and also than that of sobrerol (Table 12).

TABLE 12 Anti-inflammatory activity on the carrageenin oedema in rats.

Dosage mg/ % inhibition on the plantar kg b.w. oedema after 4 hours as from intrapen- administration (average on 6 Compound toneally animals + std. deviation) MYRTENAL 30 30 FRACTION 2 30 21 SOBREROL 30 11 4. Antihaemolyflc activity, in vitro Myrtenal at concentration of from 80 to 500 micrograms/ ml protects the red blood cells of rats from the haemolysis as induced by capillary-active agents (Tween 80) with an Effective Concentration 50% equal to 157.09 micrograms/ml (fiducial limits 95% = 112.3 - 189.9).

5. Anfiaggregative activity Myrtenal at concentrations from 160 to 1.280 micrograms/ml inhibits in vitro the thrombocyte aggregation from ADP. evaluated according to the method by Born and Cross (J.

Physiol.. London. 168. 178. 1963). to a degree which is higher than those of Fraction 2 and sobrerol.

TABLE 13 Thrombocyte aggregation : % inhibition (average of repeated tests) Final concentrations % Inhibition Control 0 Myrtenal 1280,mg/ml 75 640 " 20 320 "I 12 160 " 0 Control 0 Sorbrerol 4000 yg/ml 32 2000 " 24 1500 " 12 1000 " 4 4 Control 0 Fraction 2 1280 ,ug/ml 70 2 2 1016 " 2 806 " 14 14 2 2 640 " 0 6. Antibacterial activity Myrtenal possesses a pronounced antibacterial activity on Gram-positive germs, less intense on Gram-negative ones with a Minimum Inhibiting Concentration (MIC) of 200 micrograms/ml on Staphylococcus aureus, and of 800 micrograms/ml on Escherichia coli and is more active both an Fractions 2 and sobrerol. (Table 14) TABLE 14 Minimum Inhibiting Concentrations (MIC) in micrograms/milliliter.

Microorganism Staphylococcus Escherichia Compound aureus coli Myrtenal 200 800 Fraction 2 800 800 Sobrerol This compound, myrtenal, has shown, by way of conclusion, that it possesses a marked antibacterial action by virtue of which it distinguishes in a statistically significant way from both the terpene mixtures of Fraction 2 of Swiss Patent and the other medicinal substances of reference, Myrtenal has an anti-inflammatory action of poor magnitude, it displays an antihaemolytic activity and. finally. it has also a bronchodilating type action and an antiaggregative action as well.

On account of these particular features thereof. myrtenal is indicated as an active ingredient of medicinal compositions which are particularly suitable for the therapy of bronchop neumonial diseases when an important bacterial component is present, or when, at any rate.

an antibiotic-based therapy is required. In connection with such indications, the administration of a daily dosage of from 10 to 100 milligrams of myrtenal is suggested.

The pharmaceutical compositions according to the present invention comprising ver benone or myrtenal together with a pharmaceutically 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 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.

chemiotherapeutic substances, sulfonamide drugs. anti-inflammatory drugs. cortisone prep arations and analgesics.

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

EXAMPLE a-Alchol oxidation 100 grams of the terpene mixture of Fraction 2 of the Swiss Patent 542.163, 20-30% of which comprises compounds having a carbonyl moiety (predominantly verbenone and mvr tenal) whereas 50-60% comprises compounds having an alcoholic moiety (mainly verbenol and myrtenol) are dissolved in 2.000 mls of dry acetone.

Separately, the oxidizing solution is prepared by admixing cautiously 37.41 grams of Cr03 with 32.2 mls of conc. His04 in the quantity of water which is sufficient to make up a final volume exactly equal to 140 mls.

The chromic acid is then added slowly and dropwise to the acetone solution with stirring, cooling on an ice bath so as to maintain the temperature constantly below 30"C. On completion of the addition, filtration is carried out on a Celite (Trade Mark) and the filtrate is taken up by evaporating off acetone under reduced pressure at 40"C. The residue is then diluted with water, neutralized in cold conditions with 10%NaOH and extracted with CHCI3 until exhausting the mother liquors. The combined organic extracts are dried over anhydrous Na2SO4 and evaporated to dryness under reduced pressure at 40"C.

By so doing, there are obtained about 100 grams of a raw product which is composed, for 50-60% by compounds having a carbonyl moiety (prevailingly verbonone and myrtenal).

b - Separation ofthe carbonyl compounds from the raw material as obtained from the oxidation run n appropriate vessel is charged with 100 grams of a raw mixture as obtained from the stage a of this method, dissolved in 500 mls of ether and a solution formed by 120 grams of NaHSO3 and 72 grams of NaHOC3 in 2,000 mls of water. The mixture is vigorously shaken during about 20 hours at room temperature, and then transferred to a separatory funnel and the organic phase is discarded. The aqueous phase is washed twice with 500 mls of ether each time, whereafter the aqueous bisulfite solution is taken up and subjected to steam distillation.

The processing of the distillate gives 50-55 grams of a mixture which is virtually composed by pure verbenone and myrtenal.

c - Obtention of pure verbenone and myrtenal 50 grams of the product coming from the previous stage are subjected to fractionation in a vacuo at 20 millimeters of mercury. using a reflux column filled with nickel shavings. The distillation is carried out slowly (5 to 8 mls/hour) by maintaining a reflux ratio of about 40 to 1 the whole run throughout. The fraction which distills at 900C-950C is composed by myrtenal (19 grams) and has the following physico-chemical specifications: nn = 1.50 d20 =0.98 Infrared Analysis: bands at 1684 cm-' y C=O (conjugated) 1623 cm-' y C=C (conjugated) 1471 cam~' y C-H 1423-1387-1372 UltraViolet Analysis max(EtOH) = 246 nm (about 8400) The semicarbazone melts at 210 C-215 C.

The fraction which distills subsequently at llO"C-113"C at 20 millimeters of mercury is composed by verbenone (28.5 grams) and has the following physico-chemical specifications: Infrared "";1.49 dzo = 0.97 nn ~1.49 d20 = 0.97 Infrared bands at 1670 cam~' 7 C=O (conjugated) 1615 cm-' y CXC (conjugated) 1650-1435-1370 Ultraviolet max(EtOH) = 250 nm = 7.300 Semicarbazone : m. point 188"C-190"C WHAT I CLAIM IS: 1. A process for preparing verbenone and myrtenal from a reaction mixture resulting from the oxidation of a mixture of a-pinene and -pinene which process comprises oxidizing the reaction mixture with chromium trioxide in sulphuric acid. forming the bisulphite adducts of the verbenone and myrtenal produced. extracting the bisulphite adducts in water and fractionally distilling the extract under a reduced pressure of 20 mmHg to isolate the myrtenal at 90 C-95 C and the verbenone at 110 -113 C.

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

3. Verbenone whenever prepared by the process claimed in either claim 1 or claim 2.

4. Myrtenal whenever prepared by the process claimed in either claim 1 or claim 2.

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

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

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Separately, the oxidizing solution is prepared by admixing cautiously 37.41 grams of Cr03 with 32.2 mls of conc. His04 in the quantity of water which is sufficient to make up a final volume exactly equal to 140 mls.

The chromic acid is then added slowly and dropwise to the acetone solution with stirring, cooling on an ice bath so as to maintain the temperature constantly below 30"C. On completion of the addition, filtration is carried out on a Celite (Trade Mark) and the filtrate is taken up by evaporating off acetone under reduced pressure at 40"C. The residue is then diluted with water, neutralized in cold conditions with 10%NaOH and extracted with CHCI3 until exhausting the mother liquors. The combined organic extracts are dried over anhydrous Na2SO4 and evaporated to dryness under reduced pressure at 40"C.

By so doing, there are obtained about 100 grams of a raw product which is composed, for 50-60% by compounds having a carbonyl moiety (prevailingly verbonone and myrtenal).

b - Separation ofthe carbonyl compounds from the raw material as obtained from the oxidation run n appropriate vessel is charged with 100 grams of a raw mixture as obtained from the stage a of this method, dissolved in 500 mls of ether and a solution formed by 120 grams of NaHSO3 and 72 grams of NaHOC3 in 2,000 mls of water. The mixture is vigorously shaken during about 20 hours at room temperature, and then transferred to a separatory funnel and the organic phase is discarded. The aqueous phase is washed twice with 500 mls of ether each time, whereafter the aqueous bisulfite solution is taken up and subjected to steam distillation.

The processing of the distillate gives 50-55 grams of a mixture which is virtually composed by pure verbenone and myrtenal.

c - Obtention of pure verbenone and myrtenal

50 grams of the product coming from the previous stage are subjected to fractionation in a vacuo at 20 millimeters of mercury. using a reflux column filled with nickel shavings. The distillation is carried out slowly (5 to 8 mls/hour) by maintaining a reflux ratio of about 40 to 1 the whole run throughout. The fraction which distills at 900C-950C is composed by myrtenal (19 grams) and has the following physico-chemical specifications: nn = 1.50 d20 =0.98 Infrared Analysis: bands at 1684 cm-' y C=O (conjugated)

1623 cm-' y C=C (conjugated)

1471 cam~' y C-H 1423-1387-1372 UltraViolet Analysis max(EtOH) = 246 nm (about 8400) The semicarbazone melts at 210 C-215 C.

The fraction which distills subsequently at llO"C-113"C at 20 millimeters of mercury is composed by verbenone (28.5 grams) and has the following physico-chemical specifications: Infrared "";1.49 dzo = 0.97 nn ~1.49 d20 = 0.97 Infrared bands at 1670 cam~' 7 C=O (conjugated)

1615 cm-' y CXC (conjugated) 1650-1435-1370 Ultraviolet max(EtOH) = 250 nm = 7.300 Semicarbazone : m. point 188"C-190"C WHAT I CLAIM IS: 1. A process for preparing verbenone and myrtenal from a reaction mixture resulting from the oxidation of a mixture of a-pinene and ss-pinene which process comprises oxidizing the reaction mixture with chromium trioxide in sulphuric acid. forming the bisulphite adducts of the verbenone and myrtenal produced. extracting the bisulphite adducts in water and fractionally distilling the extract under a reduced pressure of 20 mmHg to isolate the myrtenal at 90 C-95 C and the verbenone at 110 -113 C.
2. A process as claimed in claim 1 substantially as hereinbefore described with reference to the Example.
3. Verbenone whenever prepared by the process claimed in either claim 1 or claim 2.
4. Myrtenal whenever prepared by the process claimed in either claim 1 or claim 2.
5. A pharmaceutical composition comprising. as an active ingredient. verbenone prepared by the process claimed in claim 1. together with a pharmaceutically-acceptable carrier or diluent.
6. A pharmaceutical composition comprising. as an active ingredient. myrtenal prepared by the process claimed in claim 1. together with a pharmaceutically-acceptable carrier or diluent.