Derivatives of methyl-substituted or methoxy-substituted 2-hydroxybenzoic acids, and pharmaceutical formulations containing them

Abstract

The invention relates to methyl- or methoxy-substituted 2-cynnamoyloxy-benzoic acids or to cynnamylesters of methyl- or methoxy-substituted 2-hydroxybenzoic acids, endowed with an interesting antiinflammatory, analgesic and antibacterial activity; and to a process for preparing said compounds.

Description

This invention relates to derivatives of methyl-substituted or methoxy-substituted 2-hydroxybenzoic acids of general formula (I) ##STR1## in which:

R represents hydrogen, and R' represents the cinnamoyl residue (3-phenyl-2-propenoyl); or

R represents cinnamyl (3-phenyl-2-propenyl), and

R' represents hydrogen; and

R" represents CH.sub.3 or OCH.sub.3.

The compounds (I) have marked antiinflammatory, analgesic and antibacterial activity, accompanied by very low toxicity, an excellent local tolerability, and an ulcerogenic action which is certainly less than that of known drugs. Consequently, the invention also relates to pharmaceutical formulations of antiinflammatory, analgesic and antibacterial activity containing one or more compounds of formula (I) as their active principle. Finally, the invention also relates to a process for preparing compounds of formula (I), characterised in that (a) methyl- or methoxy-2-hydroxybenzoic acids are reacted with cinnamyl alcohol (3-phenyl-2-propen-1-ol) in the presence of acid catalysts, or (b) an activated derivative of cinnamic acid (3-phenyl-2-propenoic acid) is reacted with a methyl- or methoxy-2-hydroxy-benzoic acid, in accordance with the scheme: ##STR2## in which R, R' and R" have the aforesaid meanings, and X represents a halogen atom, and alkoxyl residue or a residue such as to form a mixed anhydride with the 3-phenyl-2-propenoyl group. Preferably, reaction (a) is catalysed by anhydrous phosphoric acid, whereas in reaction (b) 3-phenyl-2-propenoyl chloride is used.

The examples given hereinafter illustrate the process according to the invention, but without limiting it. The structure of the described compounds has been confirmed by analytical and spectroscopic data.

EXAMPLE 1

(3-Phenyl-2-hydroxy-5-methylbenzoate

40.251 g of 3-phenyl-2-propen-1-ol (0.3 moles) and 4.9 g of anhydrous phosphoric acid (0.05 moles) are added to 15.24 g of 2-hydroxy-5-methylbenzoic acid (0.1 moles). The mixture is heated to 95.degree.-100.degree. C. under stirring for 24 hours. It is then cooled, and dissolved in 200 ml of ether.

The ether solution is extracted with water until the phosphoric acid is removed, then with 50 ml of a 10% potassium carbonate solution. The aqueous alkaline solution is acidified with 2N HCl. The solid precipitate is removed by filtration and washed with water heated to 60.degree.-70.degree. C.

The crude product is crystallised from 60% methanol. 24 g (yield 89.4%) of (3-phenyl-2-propenyl)-2-hydroxy-5-methylbenzoate are obtained, having a m.p. of 178.5.degree.-179.degree. C.

EXAMPLE 2

(3-Phenyl-2-propenyl)-2-hydroxy-4-methylbenzoate

Using the method of example 1, 15.24 g of 2-hydroxy-4-methylbenzoic acid (0.1 moles), 40.251 g of 3-phenyl-2-propen-1-ol (0.3 moles) and 4.9 g of anhydrous phosphoric acid (0.05 moles) give 23.9 g (89% yield) of (3-phenyl-2-propenyl)-2-hydroxy-4-methylbenzoate, m.p. 196.degree.14 196.5.degree. C.

EXAMPLE 3

(3-Phenyl-2-propenyl)-2-hydroxy-3-methylbenzoate

Using the method of example 1, 15.24 g of 2-hydroxy-3-methylbenzoic acid (0.1 moles), 40.251 g of 3-phenyl-2-propen-1-ol (0.3 moles) of 4.9 g of anhydrous phosphoric acid (0.05 moles) give 23.9 g (yield 89%) of (3-phenyl-2-propenyl)-2-hydroxy-3-methylbenzoate, m.p. 154.degree.-154.5.degree. C.

EXAMPLE 4

2-(3-Phenyl-2-propenoyloxy)-5-methylbenzoic acid

20.82 g. of SOCl.sub.2 (0.175 moles) are added to 14.815 g(0.1 moles) of 3-phenyl-2-propenoic acid, and the mixture heated under reflux for 8 hours. The excess SOCl.sub.2 is then distilled off under reduced pressure. The residue is taken up in 250 ml of anhydrous benzene, and a suspension of 15.24 g of 2-hydroxy-5-methylbenzoic acid (0.1 moles) in 250 ml of anhydrous benzene is added.

The mixture is heated under reflux for about 35 hours, is then cooled and extracted with a 5% aqueous potassium carbonate solution. The separated alkaline solution is acidified with 2N HCl. The solid precipitate is removed by filtration and washed with water heated to 60.degree.-70.degree. C.

The crude product is first crystallised from glacial acetic acid, then from 60% methanol.

23 g of 2-(3-phenyl-2-propenoyloxy)-5-methylbenzoic acid (yield 81.47%) are obtained, having a m.p. of 161.5.degree.-162.degree. C.

EXAMPLE 5

2-(3-Phenyl-2-propenoyloxy)-4-methylbenzoic acid

Using the method of example 4, 14.815 g (0.1 moles) of 3-phenyl-2-propenoic acid and 20.82 g of SOCl.sub.2 (0.175 moles) followed by 15.24 g of 2-hydroxy-4-methylbenzoic acid (0.1 moles) give 22.4 g of 2-(3-phenyl-2-propenoyloxy)-4-methylbenzoic acid (yield 81.1%), m.p. 156.5.degree.-157.degree. C.

EXAMPLE 6

2-(3-Phenyl-2-propenoyloxy)-3-methylbenzoic acid

Using the method of example 4, 14.815 g(0.1 moles) of 3-phenyl-2-propenoic acid and 20.82 g of SOCl.sub.2 (0.175 moles) followed by 15.24 g of 2-hydroxy-3-methylbenzoic acid (0.1 moles) give 23.1 g of 2-(3-phenyl-2-propenoyloxy)-3-methylbenzoic acid (yield 81.8%), m.p. 141.degree.-141.5.degree. C.

EXAMPLE 7

(2-propenyl-3-phenyl)-2-hydroxy-3-methoxy-benzoate

Using the method of example 1, 16.814 g (0.1 moles) of 2-hydroxy-3-methoxybenzoic acid, 40.251 g of 3-phenyl-2-propen-1-ol (0.3 moles) and 4.9 g of anhydrous phosphoric acid (0.05 moles) give 26.838 g (yield 90%) of (2-propenyl-3-phenyl)-2-hydroxy-3-methoxy-benzoate.

The characteristics of high activity and practical absence of side effects of the products according to the invention are illustrated hereinafter by way of example, for 2-(3-phenyl-2-propenoyloxy)-5-methylbenzoic acid (see example 4), indicated by the symbol AF1 for brevity.

1. Acute toxicity

Acute toxicity of the product was studied in the Swiss mouse and Wistar rat by oral and intraperitoneal administration. The substance was carried in 5% gum arabic for both methods of administration. The volumes inoculated for both methods of administration were 20 ml/kg of body weight for the mouse and 5 ml/kg for the rat. The LD.sub.50 values expressed in mg/kg were calculated on the seventh day of treatment by the probital analysis method.

The results are given in table 1.

TABLE 1______________________________________LD.sub.50 values in mg/kg and their 95% reliability limits(given in brackets)Animal Administration method AF1______________________________________Mouse oral 901.8 (877.4-926.8) i.p. 410.1 (373.9-451.1)Rat oral >2000 i.p. 733.8 (696.0-775.0)______________________________________

2. Subacute toxicity in the rat by intramuscular administration

The test was carried out for 25 consecutive days using drug doses of 60 and 120 mg/kg/die. The condition of the rats was always excellent, neither were there significant changes in general condition and weight.

3. Local tolerability check

A 0.5 solution of AF1 dropped into the conjunctival sac of the eye of a rabbit caused no irritating or otherwise damaging modification to local tissues. In addition, intramuscular administration of the product at a dose of 60-120 mg/kg/die for 25 consecutive days, carried out on the rat by subchronic treatment, led to no macroscopic change in the tissues where the drug was introduced, neither were other undesirable local phenomena observed.

4. Antiinflammatory activity

4.1 Edema by carrageen

The antiinflammatory activity of AF1 was evaluated in comparison with that of a known drug (Tanderil.RTM.) by inhibiting the edema induced in the rear paw of the rat by carrageen. The method used is that described by Winter.

The substances examined were administered orally to Wistar rats having a body weight of 165.+-.15 g.

The percentage edema inhibition for the various groups of animals was calculated by putting the average percentage increase of the control group equal to 100.

The results are shown in table 2.

TABLE 2______________________________________Edema by carrageen Percentage edema inhibition relativeTreatment to the controls at the followingmg/kg by times after edematigenous treatmentoral admi- (average values)No. animals nistration 4 hours 6 hours______________________________________15 Tanderil 25 58 6815 Tanderil 50 56 7815 AF1 25 42 7115 AF1 50 62 8415 AF1 75 73 87______________________________________

4.2 Edema by kaolin

The antiedematous action of AF1 was also investigated by the test of Conbon and coll. (Arch.Int.Pharmacodyn. 99; 474, 1954), consisting of measuring the diameter of the tibiotarsal joint in both the rear paws of the rat. Groups of five animals representing controls and treated animals were used for two separate experiments. 0.2 ml of a sterile 10% kaolin suspension was injected directly into the joint of the two rear paws of each animal.

The joint diameter was measured one hour after the kaolin injection and then every 24 hours afterwards for five consecutive days. The AF1 compound was administered intraperitoneally in a quantity of 100 mg/kg one hour after the kaolin injection and at the same time on the following days over the entire test period.

The results are shown in table 3.

TABLE 3______________________________________Edema by kaolin. Effect of AF1 on edema inducedby kaolin. Average of diameters (mm) Mean valuesTime after % inhibitiontreatment with Treated ani- relative tokaolin. Days Controls mals controls______________________________________0 5.9 5.8 --0 + 1 hour 6.6 6.9 --1 9.9 8.8 -11.12 10.2 8.7 -14.73 10.9 8.0 -26.64 10.3 7.9 -23.35 10.1 7.5 -25.7______________________________________

5. Analgesic activity

The analgesic activity of the compound under examination was tested in the mouse by the method of Ben Bassat and coll. (Arch. Int. Pharmacodyn, 122, 434, 1954) and comparing the drug in question with Tanderil.RTM. (T).

The relative results are illustrated in table 4.

TABLE 4______________________________________Analgesic action of the new drug and Tanderil.RTM. inthe mouse. % Increase in the painful reaction Treatment time relative to the controls, at theNo. mg/kg by following minutes after administra-ani- oral admi- tionmals nistration 30 min. 60 min. 90 min. 120 min. 150 min.______________________________________20 T 100 11 14 15 20 2120 AF1 100 22 32 36 48 51______________________________________

6. Ulcerogenic action

The ulcerogenic action of the product was evaluated in the female Wistar rat in comparison with that of other known antiinflammatory drugs.

Animals were used having a body weight of between 150 and 180 g, and which had fasted for 24 hours before treatment. The products were administered orally in a dose corresponding to about two fifths their LD.sub.50.

The animals were sacrificed four hours after treatment, and the stomachs examined to check any presence of ulcers.

The results are given in table 5.

TABLE 5______________________________________Ulcerogenic action No. of ulcerated animals/Product Dose mg/kg No. of treated animals______________________________________AF1 400 0/10AF1 800 1/10Naproxen 200 5/10Phenylbutazone 200 4/10______________________________________

Even in mice treated for 5 consecutive days with 200 mg/kg per day of AF1, there was no sign of any gastric or duodenal lesion.

7. "In vitro" antibacterial activity

The antiseptic power of the substance under examination was evaluated by determining the minimum inhibiting concentration (C.M.I.) on a series of Gram negative and Gram positive germs related to the pathology of the respiratory tree.

The culture broth used was Difco nutrient broth, and 8 test samples were used for each concentration tested. Guaiacol was used as the comparison drug.

The results are given in table 6.

TABLE 6______________________________________Minimum inhibiting concentration on thefollowing microorganisms - (mcg/ml) Micro- Micrococ- coccus Micrococ- Haemophilus Sarcina cus catar- pyoge- cus tuberc. influeniae lutea rhalis nes (bovis)(Gram) (-) (+) (-) (+) (+)______________________________________ProductGuaiacol 33,000 33,000 16,600 33,000 33,000AF1 16,000 9,150 4,300 16,600 3,150______________________________________

The compounds of the invention can be used in therapy in various pharmaceutical formulations, examples of which are as follows, in each case with reference to 2-(3-phenyl-2-propenoyloxy)-5-methylbenzoic acid (AF1).

______________________________________100 mg tabletsAF1 100 mglactose 150 mgpotato starch 30 mgmagnesium stearate 2 mg 282 mg100 mg pillsAF1 100 mglactose 100 mgcorn starch 30 mgmagnesium stearate 2 mg 232 mg200 mg capsulesAF1 200 mglactose 150 mgcorn starch 30 mgmagnesium stearate 2 mg 382 mg150 mg suppositoriesAF1 150 mgbase for suppositories(semisynthetic glycerides) 1550 mg 1700 mg300 mg vaginal ovulesAF1 300 mgbase for ovules 2400 mg(semisynthetic glycerides)quantity required to total 2700 mg3% dermatological ointmentAF1 3 gethyl alcohol 70 gvaseline oil 100 g50 cm.sup.3 sprayEach 50 cm.sup.3 bottle contains:micronised AF1 1.000 gcalcium stearate 0.500 gisopropyl myristrate 40.000 gcompressed nitrogenquantity required to total 50 cm.sup.3______________________________________

Claims

1. Derivatives of methyl-substituted or methoxy-substituted 2-hydroxybenzoic acids of general formula (I) ##STR3## in which: R represents hydrogen, and R' represents the cinnamoyl residue (3-phenyl-2-propenoyl); or

R represents cinnamyl (3-phenyl-2-propenyl), and R' represents hydrogen; and

R" represents CH.sub.3 or OCH.sub.3.

2. A compound as claimed in claim 1, which is (2-propenyl-3-phenyl)-2-hydroxy-5-methyl benzoate.

3. A new compound as claimed in claim 1, which is (2-propenyl-3-phenyl)-2-hydroxy-4-methyl-benzoate.

4. A new compound as claimed in claim 1, which is (2-propenyl-3-phenyl)-2-hydroxy-3-methyl-benzoate.

5. A new compound as claimed in claim 1, which is 2-(3-phenyl-2-propenoyloxy)-5-methylbenzoic acid.

6. A new compound as claimed in claim 1, which is 2-(3-phenyl-2-propenoyloxy)-4-methylbenzoic acid.

7. A new compound as claimed in claim 1, which is 2-(3-phenyl-2-propenoyloxy)-3-methylbenzoic acid.

8. A new compound as claimed in claim 1, which is (2-propenyl-3-phenyl)-2-hydroxy-3-methoxybenzoate.

9. Pharmaceutical compositions of antiinflammatory, analgesic and antibacterial activity, characterised by containing at least one compound as claimed in claim 1 as their active principle.