IL39467A - 5,5'-((hydroxytrimethylene)dioxy)bis(4-oxo-4h-1-benzopyran-2-carbohydroxamic acid),its preparation and pharmaceutical compositions containing it - Google Patents

Description

FISOBS LIMITED α· 5755 BA 19837/71 This invention relates to new benzopyran derivatives, compositions containing them and methods for their preparation.

According to our invention we provide compounds of salts and pharmaceutically acceptable doipivati¥Os tliereof.

According to our invention we also provide a process for the production of a compound of formula I, or a pharmaceutically salt acceptable drivatie thereof, which comprises (a) treating an anhydride, ester or acid halide of a compound of formula II, with hydroxylamine , (b) selective dehydrogenation of a compound of formula IV, (c) selective hydrogenation or hydrolysis of a compound of formula V, in which Y represents a group which is convertible to a hydrogen atom by hydrogenation or hydrolysis, and where desired or necessary converting the compound salt of formula I to a pharmaceutically acceptable derivative thereof.

In process (a) the anhydride is preferably a mixed anhydride of such a type that it will cleave preferentially, to give the desired benzopyran-2-carbohydroxamic acid, as the major product when reacted with hydroxylamine. Examples of suitable acids from which the mixed anhydride may be derived are sulphonic acids e.g. benzene sulphonic acid, sterically hindered carboxylic acids, e.g. pivalic, isovaleric, diethylacetic or triphenylacetic acid, and alkoxy formic acids, e.g. ethoxy or isobutoxy formic acid. The reaction is preferably carried out under anhydrous conditions in a solvent which will not react with either the hydroxylamine or the mixed anhydride, e.g. pyridine or dimethylformamide. However, when the reaction is carried out in a non-basic solvent, e.g. dimethylformamide , at least four molar equivalents of an acid acceptor, e.g. triethylamine , should also preferably be present. The reaction is preferably carried out - U - at a temperature of from about -15° to +20°C. When an acid halide is used it may conveniently be an acid chloride. Suitable esters of compounds of formula II include those derived from alkanols containing from 1 to 10 and preferably from 1 to 6 carbon atoms. When an ester is used the reaction may conveniently be carried out in a solvent which is inert under the reaction conditions, e.g. dimethylformamide , in the presence of a base, e.g. sodium hydroxide, and at room temperature, i.e. at about 20°C.

In process (b) the dehydrogenation may be carried out using, for example selenium dioxide, palladium black, chloranil dichloro-dicyanoquinone or sulphur. Alternatively the dehydrogenation may be carried out indirectly by halogenation followed by dehydrohalogenation , e.g. by treatment with N-bromosuccinimide or pyridinium bromide perbromide to yield the 3-bromo derivative which is subsequently dehydrobrominated.

In process (c) the group Y may be , for example , a benzyl group which may be removed by hydrogenation , e.g. using a conventional catalyst. Alternatively the group Y may be an acyl (e.g. lower alkanoyl) group which may be removed by hydrolysis.

The compounds of formula I may be recovered from the reaction mixture using conventional techniques.

The compounds of formula II are known and their esters anhydrides and acid halides may be made in conventional manner.

Thus the anhydrides of the compounds of formula II may be made by reaction of an acid halide of one of the acids with the other acid, e.g. the reaction of a sulphonyl chloride or an alkyl chloroformate with the acid of formula II. The reaction may be carried out under the conditions described above for the use of an anhydride in process (a).

Compounds of formula IV may be made by selective hydrogenation of a corresponding compound of formula I, or of a suitably -protected derivative thereof. Compounds of formula IV may also be made by cyclisation of a compound of formula VI, in which M is hydrogen or an alkali metal, for example by treatment of the compound of formula VI with a base or acid in a solvent which is inert under the reaction conditions.

The compounds of formula VI may be made by reacting a compound of formula VII, or an ester thereof, with hydroxylamine . The compounds of formula VII may be made by reacting an appropriate bis-phenolic compound with maleic arihydride. The compounds of formula V may be made by conventional techniques from known starting materials and compounds of formula I.

Some of the groups in the starting materials may be effected by the reaction conditions described above. It is therefore contemplated that where necessary or desirable the reaction be carried out using protected derivatives of the reagents. Thus free -OH groups may be protected, for example by acylation and the protecting group removed subsequently, e.g. by hydrolysis.

It will be appreciated that the groups -C0NH0H represented above may also exist in the tautomeric form -C(0H)=N-0H and this tautomeric form of the compounds of formula I is also included in our invention.

The processes described above may produce the compound of formula I or a derivative thereof. It is also within the scope of this invention to treat any derivative so produced to liberate the free compound of formula I, or to convert one derivative into another.

Pharmaceutically acceptable derivatives of the compounds of formula I include pharmaceutically acceptable salts. Suitable salts include water soluble salts, for example ammonium, alkali metal (e.g. sodium potassium and lithium) and alkaline earth metal (e.g. calcium or magnesium) salts and salts with suitable organic bases, e.g. salts with lower alkyl amines, e.g. methylamine or ethylamine, with substituted lower alkylamines, e.g. hydroxy substituted alkylamines , or with simple monocyclic nitrogen heterocyclic compounds, e.g. piperidine or morpholine.

The compounds of formula I and pharmaceutically acceptable salts derivatives thereof are useful because they possess pharmacological activity in animals; in particular they are useful because they inhibit the release and/or action of pharmacological mediators which result from the in vivo combination of certain types of antibody and specific antigen, e.g. the combination of reaginic antibody with specific antigen (see Example A). In man, both subjective and objective changes which result from the inhalation of specific antigen by sensitised subjects are inhibited by prior administration of the compounds. Thus the compounds are indicated for use in the treatment of asthma, e.g. allergic asthma. The compounds are also indicated for use in the treatment of so-called 'intrinsic' asthma (in which no sensitivity to extrinsic antigen can be demonstrated). The compounds may also be of value in the treatment of other conditions in which antigen-antibody reactions are responsible for disease , for example, hay fever and urticaria.

For the above mentioned uses the dosage administered will, of course, vary with the compound employed, the mode of administration and the treatment desired. However, in general, satisfactory results are obtained when the compounds are administered at a dosage of from 0.1 to 50mg per kg of animal body weight in the test set out in Example A. For man the total daily dosage is in the range of from about 1 mg to 3,500/5 mg which may be administered in divided doses from 1 to 6 times a day or in sustained release form. Thus dosage forms suitable for adirdnistration (e.g. by inhalation) comprise from about 0.17 mg to 600 mg, preferably 30 to 600 mg, of the compound admixed with a solid or liquid pharmaceutically acceptable diluent, adjuvant or carrier..

According to the invention there is also provided a process for the production of a pharmaceutically acceptable salt of a compound of formula I, which comprises treating a compound of formula I, or another salt thereof, with a compound, e.g. a base or ion exchange resin, containing an available pharmaceutically acceptable cation, e.g. sodium, potassium, calcium, ammonium, and appropriate nitrogen containing cations. In general we prefer to form the pharmaceutically acceptable salt by treating the free acid of formula I with an appropriate base, e.g. with an alkaline-earth or alkali metal hydroxide, carbonate or bicarbonate in aqueous solution or by treating a salt of a compound of formula I with another salt by a metathetical process. When a strongly basic compound is used care should be taken, e.g. by keeping the temperature sufficiently low, to ensure that the compound of formula I is not hydrolysed or otherwise degraded. The pharmaceutically acceptable salt may be recovered from the reaction rnixture by, for example, solvent precipitation and/or removal of the solvent by evaporation, e.g. by freeze drying.

According to our invention we also provide a pharmaceutical composition comprising (preferably a minor proportion of) a salt compound of formula I, or a pharmaceutically acceptable dor-ivati' thereof, in combination with a pharmaceutically acceptable adjuvant, diluent or carrier. Examples of suitable adjuvants, diluents or carriers are:- for tablets and dragees; lactose, starch, talc or stearic acid; for capsules, tartaric acid or lactose; for suppositories, natural or hardened oils or waxes; for inhalation compositions, coarse lactose. For use in inhalation compositions the compounds of formula I, or the pharmaceutically acceptable derivative thereof, preferably has a fine particle size of from 0.01 to 10 microns and may if desired be used i combination with a bronchodilator, e.g. isoprenaline. The compound of fine particle size may be made, for example by grinding or milling. The compositions may also contain suitable preserving, stabilising and wetting agents, solubilizers , sweetening and colouring agents and flavourings. The compositions may, if desired, be formulated in sustained release form.

The invention is illustrated, but in no way lindted by the following Examples, in which the parts are by weight. - - 3*- Example 1 a) Di-sodium 5 ,5 ' -.T(2-hydroxytrimethylene)dioxy7bis(H--oxo-4H-l- benzopyran-2-carbohydroxamate)dihydrate.

A solution of hydroxylamine (2.64g; 0.08 mole) in ethanol (160 ml) was added to a suspension of diethyl 5 ,5'-"(2-hydroxy-trimethylene)dioxy/bis(4-oxo-4H-l-benzopyran-2-carboxylate (10.5g 0.02 mole) in ainethylformamide (50 ml). To this mixture, stirred at room temperature, a solution of sodium hydroxide (1.6g; 0.04 mole) in ethanol (40 ml) was added dropwise over a period of 2 hours. The mixture became yellow on addition of alkali and it was stirred overnight at room temperature. The resulting yellow precipitate was filtered off, washed with ethanol and dried in vacuo (10.8g). This was recrystallized from water/acetone to afford pure disodium 5 ,5' t2--hydroxytrim3thylene) dioxy/bis(4-oxo-4H-l-benzopi- i--2-carbohydroxamate)dihydrate (6.8g; 64% yield of theory).

Analysis: Found; C, 47.4; H, 3.7; M, 4.7% C23H16N2Na2°ir2H2° rc¾ui:res: C, 47.7; H, 3.5; , 4.8% Spectral Confirmation The nmr spectrum in hexadeuterodimethylsulphoxide revealed a two proton singlet resonance at 3.5¾rfor the 3 and 3'-protons of the benzopyran rings. b) 5 ,5' (2-l^droxytrijinethylene)dioxy7bis(4-oxo-4H-l-benzopyran-2- carbohydroxamic acid) sesquihydrate.

Di-sodium 5 ,51-"(2-hydroxytrimethylene)dioxy7bis(4-oxo-4H-l- - - tenzopyran-2-carlx)hydrOxamte)dihydrate (1.5g) was dissolved in water (50 ml) and the resulting solution was acidified to H 4-.0 by dropwise addition of glacial acetic acid. The resulting precipitate of 5,5'-/T(2-hydroxytrimethylene)dioxy7-bis(4^xo-UH-l-benzopyran-2-carbohya^xamic acid) was collected, washed with water and dried in vacuo, (l.lg) mp 198°C (decomp.). Analysis: Found; C, 52.9; H, 3.9; N, 5.1% C23¾8N2°11'1¾° re¾u:ires: c> 52-6^ H> 3·9> 5·1% Spectral Confirmation The nmr spectrum in hexadeuterodimethylsulphoxide revealed a two proton singlet resonance at 3.4Ψτ for the 3 and 3'-protons of the benzopyran rings.

Example A The procedure set out below may be used to assess the effectiveness of a compound in inhibiting the release of the pharmacological mediators of anaphylaxis.

In this test, the effectiveness of the compounds in inhibiting the passive cutaneous anaphylactic reaction in rats is assessed. It has been proved that this form of test gives reliable qualitative indications of the ability of the compounds under test to inhibit antibody-antigen reactions in man.

In this test method Charles River France/Fisons bred rats (male or female) having a body weight of from 100 to 150 gms are infected subcataneously at weekly intervals with N. brasiliensis larvae in doses increasing from about 2000 larvae per animal to 12000 larvae per animal in order to establish the infection. After 8 weeks the rats are bled by heart puncture and 15-20 mis of blood collected from each animal. The blood samples are then centrifuged at 3500 rpm. for 30 minutes in order to remove the blood cells from the blood plasma. The serum is collected and used to provide a serum containing N. brasiliensis antibody. A pilot sensitivity test is carried out to determine the least quantity of serum required to give a skin weal in control animals in the test described below of 2 cm diameter. It has been found that optimum sensitivity of rats in the body weight range 100-130 gms is obtained using a serum diluted with eight parts of physiological saline solution. This diluted solution is called antibody serum A.

The antigen to react with the antibody in serum A is prepared by removing N. brasiliensis worms from the gut of the infested rats, centrifuging the homogenate and collecting the supernatent liquor. This liquor is diluted with saline to give a protein content of 1 mg/ml and is known as solution B.

Charles Pdver France/Fisons bred rats in the body weight range 100 to 130 gms are sensitised by intra dermal injection of 0.1 mis of serum A into the right flank. Sensitivity is allowed to develop for 24 hours and the rats are then injected intravenously with 1 ml/100 gms body weight of a mixture of solution B (0.25 mis), Evans Blue dye solution (0.25 mis) and the solution of the compound under test (0.5 mis varying - - ^ - 13 percentages of active matter). Insoluble compounds are administered as a separate intraperitoneal injection 5 minutes before intravenous administration of solution B and Evans Blue dye. For each percentage level of active matter in the solution under test five rats are injected. Five rats are used as controls in each test. The dosages of the compound under test are selected so as to give a range of inhibition values.

Thirty minutes after injection of solution B the rats are killed and the skins are removed and reversed. The intensity of the anaphylactic reaction is assessed by comparing the size of the characteristic blue weal produced by the spread of the Evans Blue dye from the sensitisation site, with the size of the weal in the control animals. The size of the weal is rated as 0 (no weal detected, i.e. 100% inliibition) to 4 (no difference in size of weal, i.e. no inhibition) and the percentage inhibition for each dose level calculated as:- (Control group score - treated group score) x 100 % inhibition = Control group score The percentage inhibitions for the various dose levels are plotted graphically for each compound. From these graphs the dosage required to achieve a 50% inhibition of the anaphylactic reaction (IDJ-Q) may be determined.

The compounds are also evaluated in the above manner using intestinal and gastric administration of the compound. - -

Claims (11)

1. - 14 What We Claim is 1) A process for the production of a compound of formula I, salts and pharmaceutically acceptable dorivativoo thereof, which comprises (a) treating an anhydride, ester or acid halide of a compound of formula II, with hyo^xylamine , (b) selective dehydrogenation of a compound of formula IV, (c) selective hydrogenation or hydrolysis of a compound of formula 15 - in which Y represents a group which is convertible to a hydrogen atom by hydrogenation or hydrolysis , and where desired or necessary converting the compound salt of formula I to a pharmaceutically acceptable data atiiva thereof.

2. ) A process according to part (a) of Claim 1, wherein the anhydride is a mixed anhydride derived from a sulphonic acid, a sterically hindered carboxylic acid, or an alkoxy formic acid.

3. ) A process according to part (a) of Claim 1, wherein the acid halide is the acid chloride.

4. ) A process according to part (a) of Claim 1, wherein the ester is derived from an alkanol containing from 1 to 10 carbon atoms.

5. ) A process according to part (b) of Claim 1, wherein the dehydrogenation is carried out using selenium dioxide, palladium black, chloranil, dichloro-dicyanoquinone or sulphur, or by halogenation followed by dehydrohalogenation.

6. ) A process according /to part (c) of Claim 1, wherein Y is a benzyl group or an acyl group.

7. ) A process for the production of a pharmaceutically acceptable salt of a compound of formula I, as defiaed in Claim 1, which comprises treating a compound of formula I, or another salt thereof, with a compound containing an available pharmaceutically acceptable cation.

8. ) A process according to Claim 7, which comprises treating the free acid of formula I with an appropriate base in aqueous - 16 - solution or treating a salt of a compound of formula I with another salt by a metathetical process.

9. ) A process according to Claim 1 substantially as hereinbefore described in Example 1.

10. ) A compound of formula I as defined in Claim 1, or a sal pharmaceutically acceptable dor-ivativc thereof, whenever produced by a process according to any one of the preceding claims.

11. ) A compound of formula I as defined in Claim 1, or a salt pharmaceutically acceptable derivative thereof. 12) 5,5'- (lfydrOxytrimethylene)dioxy^ carbohydroxamic acid). 13) A compound according to Claim 11 or Claim 12 in the form of the free acid or a pharmaceutically acceptable salt thereof. 14) A compound according to Claim 13 in the form of a sodium salt thereof. 15) A compound according to any one of Claims 10 to 14 having a particle size of from 0.01 to 10 microns. 16) A pharmaceutical composition comprising a compound according to any one of Claims 10 to 15, as active ingredient, in admixture with a pharmaceutically acceptable adjuvant, diluent or carrier. 17) A composition according to Claim 16 comprising from 0.17 mg to 600 mg of active ingredient in unit dosage form. 18) A pharmaceutical composition according to Claim 16 substantially as hereinbefore described.