GB2104074A - Fluorinated diaminohexane derivatives - Google Patents

Abstract

Novel fluorinated alkylene diamine derivatives are inhibitors of ornithine decarboxylase enzyme and have the following general Formula I:- <IMAGE> wherein p represents 1 or 2.i

Description

SPECIFICATION Fluorinated diaminohexane derivatives Field of the invention The invention relates to novel pharmaceutically useful fluorinated alkylene diamine derivatives which in vivo are inhibitors of a decarboxylase enzyme involved in polyamine formation in organisms.

The invention provides the compounds per se, pharmaceutical compositions comprising said compounds, methods of medical treatment using said compounds, and processes for preparing said compounds.

Background of the invention The decarboxylation of ornithine to putrescine, a reaction catalyzed by the enzyme ornithine decarboxylase (ODC), is the first step in the biosynthesis of the polyamines known as spermidine and spermine. Spermidine is formed by the transfer of an activated aminopropyl moiety from S-adenosyl Smethyl homocysteamine to putrescine, while spermine is formed by the transfer of a second aminopropyl group to spermidine. S-Adenosyl S-methyl homocysteamine is formed by the decarboxylation of S-adenosylmethionine (SAM), a reaction catalyzed by the enzyme S-adenosylmethionine decarboxylase (SAM-DC).

The polyamines, which are found in animal tissues and microorganisms, are known to play an important role in cell growth and proliferation. The onset of cell growth and proliferation is associated with both a marked increase in ODC activity and an increase in the levels of putrescine and the polyamines. Although the exact mechanism of the role of the polyamines in cell growth and proliferation is not known, it appears that the polyamines may facilitate macromolecular processes such as DNA, RNA, or protein synthesis. Polyamine levels are known to be high in embryonic tissue; in the testes, ventral prostrate, and thymus; in tumor tissue; in psoriatic skin lesions; and in other cells undergoing rapid growth or proliferation.

Since putrescine is the precursor of both spermidine and spermine, blockade of the conversion of ornithine to putrescine, such as by inhibition of ODC, should prevent new biosynthesis of these polyamines and, thus, provide beneficial physiological effects.

We have disclosed in U.K. Patent Specification No. 2003276A that inter alia compounds of the following Formula A are inhibitors of ornithine decarboxylase:-

Formula A wherein p represents 1 or 2.

Summary of the invention The compounds of the invention are represented by the following general Formula I:-

Formula I wherein p represents 1 or 2.

Pharmaceutically acceptable salts and individual optical isomers of the compounds of general Formula I are also within the scope of'the invention.

The compounds of Formula I inhibit ornithine decarboxylase enzyme (ODC) in vitro and in vivo and produce a decrease putrescine and spermidine concentrations in cells in which active biosynthesis of polyamines is taking place. The compounds of Formula I, therefore, are useful in mammals for controlling undesirable cell growth or proliferation. The compounds of Formula I are useful pharmacological agents for treating those diseases or conditions that are known in the art to be characterized by high ODC activity. In particular, the compounds are useful systemically for controlling the growth of tumor tissues in mammals, for treating benign prostatic hypertrophy and for controlling the growth of pathogenic parasitic protozoa in infected domestic animals and humans.

The compounds of Formula I can also be employed to study the presence and physiological function of ODC inhibition in biological systems and its relationship to pathological processes.

It will be recognized that the compounds of Formula I can be substituted at an amino group with any group known in the art to be capable of cleavage in vivo (enzymatically or chemically) to generate a free amino group. Compounds which contain such cleavable substituents and which, therefore, can be converted in vivo to a compound of Formula I will be equivalent to the compound of Formula I for the purposes of this invention. Such derivatives can be prepared in manner known per se from the compounds of Formula I. A presently preferred derivative is N-glutamyl.

The ODC activity of the compounds can be determined in vitro by the method described by B.

Metcalf et al. J. Am. Chem. Soc., 100, 2551 (1 978). The ODC activity of the compounds of Formula I can be determined in vivo by the method of C. Danzin, Biochemical Pharmacology, 28,627(1979).

Detailed description of the invention In the above general Formula I, p represents 1 or 2. It will be appreciated that when p represents 1 , the compounds of the invention are monofluoromethyl derivatives, and when p represents 2, they are mixed mono- and di-fluoromethyl derivatives.

Illustrative examples of pharmaceutically acceptable salts of the compounds of this invention include non-toxic acid addition salts formed with inorganic acids, such as hydrochloric, hydrobromic, sulfuric and phosphoric acid, or with organic acids, such as, organic carboxylic acids, for example salicylic, maleic, malonic, tartaric, citric and ascorbic acids, and organic sulfonic acids, for example methane sulfonic acid. The salts are prepared by conventional means.

In a presently preferred embodiment of the invention p is 1.

The presently preferred compounds of the present invention are the following: 1 ,1 ,6-trifluoro-2,5-diamino-hexane; and especially, 1 ,6-difluoro-2,5-diamino-hexane; It is believed that the compounds of general Formula I are "substrate-induced irreversible inhibitors" of ornithine decarboxylase. Such inhibitors are also known in the art as "enzyme-activated irreversible inhibitors", "suicide enzyme inhibitors", "that inhibitors", or "mechanism-based inhibitors".

In order for a compound to be a substrate-induced irreversible enzyme inhibitor, the compound must be a substrate for the target enzyme, and the compound must contain a latent reactive group susceptible to being unmasked as the result of the normal catalytic action of the enzyme. The unmasking of the latent reactive group by the action of the enzyme generates a reactive function which alkylates a nucleophilic residue present at the active site of the enzyme. Thus, there is formed a covalent bond between the inhibitor and the enzyme at the active site resulting in irreversible inactivation of the enzyme. Such inhibitors are extremely specific since the inhibitor must be a substrate for the target enzyme and since biotransformation of the inhibitor by the target enzyme is required before the enzyme is inactivated.Although it is believed that the compounds of general Formula I generally exert their action by means of a substrate-induced mechanism, inhibition may occur by other mechanisms, such as by competitive inhibition.

As used herein, the term "tumor tissue" means both benign and malignant tumors or naoplasms, and includes leukemias, lymphomas, melanomas, and sarcomas. The term "controlling the growth of tumor tissue" as used herein means slowing, interrupting, arresting, or stopping the growth of a rapidly proliferating tumor in a warm blooded animal. It should be understood that the administration of a compound of the Formula I does not provide a "cure" for the tumor in the sense that the tumor tissue is destroyed or totally eliminated from the animal being treated.

For controlling the growth of tumor tissues, a compound of Formula I can be administered to the patient in conjunction with other therapeutic methods or in combination with cytotoxic drugs known in the art to be useful for cancer chemotherapy. For example, a compound of Formula I can be administered in conjunction with surgical excision of the tumor or with radiation therapy, hormonal treatment, immunotherapy, or local heat therapy. Moreover, in a preferred manner, a compound of Formula I can be administered to a patient in combination with a chemical cytotoxic agent known in the art to be useful for tumor chemotherapy. When such combination therapy is employed for the treatment of a tumor, the cancer chemotherapeutic agent may be administered at a dosage known in the art to be effective for treating the tumor.However, a compound of Formula I may produce an additive or synergistic effect with a chemotherapeutic agent against a particular tumor. Thus, when such combination antitumor therapy is used, the dosage of the chemotherapeutic agent administered may be less than that administered when the agent is used alone. In combination with a compound of Formula I, the chemotherapeutic agent may, therefore, be administered at a lower dosage level or at less frequent intervals as compared to the chemotherapeutic agent when used alone.

In combination with a compound of Formula I, any cancer chemotherapeutic agent may be employed. Drugs commonly used for cancer chemotherapy are described in The Medical Letter, Vol.

22, No. 24 (Issue 571), November 28, 1 980. Published by the Medical Letter, Inc., New Rochelle, N.Y., 10801. Illustrative examples of cytotoxic chemotherapeutic agents are cyclophosphamide, methotrexate, prednisone, 6-mercaptopurine, procarbozine, daunorubicin, vincristine, vindesine, vinblastine, chlorambucil, cytosine arabinoside, 6-thioguanine, thio TEPA, 5-fluorouracil, 5-fluoro-2deoxyuridine, 5-azacytidine, nitrogen mustard, 1 ,3-bis(2-chloroethyl)-1 -nitrosourea (BCNU), 1-(2 chloroethyl)-3-cyclohexyl-1 -nitrosourea (CCNU), busulfan, adriamycin, bleomycin, cycloleucine or methylglyoxal bis(guanylhydrazone) (MGBG). Other cancer chemotherapeutic agents will be apparent to those skilled in the art.

The effect of the compounds of Formula I for the control of the growth rate of rapidly proliferating tumor tissue can be assessed in standard animal tumor models after oral or parenteral administration.

For example, the antitumor effects can be demonstrated in the following models: (a) L1210 leukemia in mice, (b) EMT 6 tumor in Balb/C mice, (c) 7,1 2-dimethylbenzanthracene-induced (DMBA-induced) mammary tumor in rats, or (d) Morris 7288 C or 5123 hepatoma in Buffalo rats. In addition, the antitumor effects of the compounds in combination with chemotherapeutic agents can be demonstrated in animal models.

When, in the treatment of a malignent neoplastic disease, a compound of Formula I is administered in combination with a chemotherapeutic agent, the therapeutic effect of the chemotherapeutic agent may be potentiated in that the remission produced by the chemotherapeutic agent may be enhanced and regrowth of the tumor tissue may be slowed or prevented. Use of such combination therapy therefor allows smaller doses or fewer individual doses of the chemotherapeutic agent to be employed. Thus, the detrimental and/or debilitating side effects of the chemotherapeutic agent are minimized while, at the same time, the antitumor effects are enhanced.The term "combination therapy" contemplates the administration of a compound of Formula I immediately prior to the beginning of chemotherapy, concommitantly with chemotherapy, or during the period of time immediately following cessation or discontinuance of chemotherapy.

When chemotherapy results in remission of the tumor and all tumor cells are not destroyed, regrowth of the tumor may be prevented or slowed indefinitely by continued treatment with a compound of Formula I. Thus, a compound of Formula I can be administered to stop or slow the growth of the tumor during the periods when chemotherapy using a cytotoxic agent may be temporarily discontinued.

A preferred cytotoxic agent for combination therapy with a compound of Formula I is methylglyoxal bis(guanylhydrazone), herein referred to as MGBG, which is also an inhibitor of Sadenosyl methionine decarboxylase. The activity of MGBG as a chemotherapeutic agent in the treatment of neoplastic diseases is well documented. For example, W. A. Knight et al. Cancer Treat.

Rep., 43, 1933, (1979) have reported that a dose of MGBG administered intravenously once or twice week to patients in the advanced stages of carcinoma of the bladder, esophagus, lung, pancreas, colon, kidney, breast and prostate, oat cell carcinoma, adenocarcinoma, lymphoma, hepatoma, melanoma, leukemia, or Edwing's sarcoma produced measurable regression of the tumor in many of the patients treated and complete disappearance of the disease in two of the 65 treated patients.

The amount of MGBG to be administered may be the same as the amount known in the art to be effective for tumor therapy. Effective and non-toxic dosages are determined by the physician in each case, taking into account the condition of the individual patient. For example, a dosage of 250 500mg per meter2 of body surface area may be infused once or twice weekly in 100ml of aqueous 5% dextrose solution over a 30 min period. Combination therapy with a compound of Formula I improves the response of the tumor tissue to the cytotoxic effect of MGBG and permits the use of a smaller individual dose of MGBG and a shorter course of treatment than would be required with the use of MGBG alone.

Suitable dosages of the compounds of Formula I for use in combination therapy with MGBG or other cancer chemotherapeutic agents can be any amount effective in inhibiting polyamine biosynthesis sufficiently to control the tumor growth rate or to achieve a heightened response to the cytotoxic agent administered in conjunction therewith.

The term "controlling the growth of pathogenic parasitic protozoa", as used herein, means slowing, interrupting, arresting, or stopping the replication of the protozoa in an infected host. The compounds of Formula I are particularly useful against T. b. brucei (which causes trypanosomiasis in cattie), T. b. rhodesiense, (which causes human sleeping-sickness), the coccidia, for example, Eimeria tenella (which causes intestinal coccidiosis in fowl (e.g. chickens, turkeys, and ducks)) and the exoerythrocytic form of plasmodia, for example, plasmodium falciparum (which causes human malaria).

The antiprotazoal activity of the compounds of Formula I can be demonstrated in vivo or in vitro in standard microbiological test procedures. For example, the activity of the compounds against T. b.

brucei, and T. b. rhodesiense can be determined in infected mice by administering the test compound ad lib daily (3 to 15 days post infection) as a solution in the drinking water. Activity is indicated by an increase in survival time (as compared to untreated controls) or by the absence of parasites in the blood The activity of the compounds against the coccidia can be determined in infected chickens, for example those infected with E. tenella by administering the test compound daily ad lib (from one day pre injection to five days post infection) as a solution in the drinking water. The cecal lesions are evaluated by a standard lesion scoring procedure. (See Reid. Am. J. VetRes., 30,447 (1969) andAvian Coccidiosis, P. Long. Editor, British Poultry Science, Ltd., Edinburgh).The activity of the compounds against malaria (p. faleiparum) can be determined by a standard in vitro plate culture test (See K.

Rieckmann et al, Lancet, 1,22 (1978)). Antimalarial activity can also be determined in special strains of mice infected with the exoerythrocitic form of p. berghei. In this test, the compound is administered adlib in drinking water starting two days preinfection and continuing 28 days post-infection. Activity is measured by a significant decrease in deaths as compared to controls or by a significant increase in survival time.

The compounds of this invention can be adm,nistered in various manners to achieve the desired effect. The compounds can be administered alone or in the form of pharmaceutical preparations either orally or parenterally, for example, subcutaneously, intravenously or interperitoneally. The amount of novel compound administered will vary and can be any effective amount. Depending upon the patient, the condition being treated and the mode of administration, the effective dosage of the compound administered may vary from about 5 mg/kg to about 500 mg/kg, of body weight of the patient per day.

Unit doses of these compounds can contain, for example, from about 10 mg to 500 mg of the compounds and may be administered, for example, from 1 to 4 times daily.

The term "unit dosage form" is used herein to mean a single or multiple dose form containing a quantity of the active ingredient in admixture with or otherwise in association with the diluent or carrier, said quantity being such that one or more predetermined units are normally required for a single therapeutic administration. In the case of multiple dose forms such as liquids or scored tablets, said predetermined unit will be one fraction, such as a 5 ml (teaspoon) quantity of a liquid or a half or quarter of a scored tablet, of the multiple dose form.

In the composition aspect of the invention there are provided pharmaceutical formulations in which form the active compounds of the invention will normally be utilized. Such formulations are prepared in a manner well known per se in the pharmaceutical art and usually comprise at least one active compound of the invention in admixture or otherwise in association with a pharmaceutically acceptable carrier or diluent therefor. For making these formulations the active ingredient will usually be mixed with a carrier, or diiuted by a diluent, or enclosed or encapsulated in a capsule, sachet, cachet, paper or other container. A carrier or diluent may be solid, semi-solid or liquid material which serves as a vehicle, excipient or medium for the active ingredient. Suitable carriers or diluents are well known per se.

The formulations of the invention may be adapted for enteral or parenteral use and may be administered to the patient in the form of tablets, capsules, suppositories, solutions, suspensions or the like.

In the specific examples included hereinbelow illustrative examples of suitable pharmaceutical formulations are described.

Methods of preparing the compounds of Formula I will now be described. If in any of the reaction steps described an amino group of a reactant would be involved in an unwanted reaction under the relevant reaction conditions, the amino group will be protected in manner known per se by introduction of an appropriate protecting group. The protecting group will be chosen having regard to the nature of the relevant reaction and ease of removal to free the amino group. The protecting group can be selected from, for example, acyl, for example, lower alkanoyl, e.g. acetyl, propionyl, trifluoroacetyl, and the like; aroyl, e.g. benzoyl, toluoyl and the like; lower alkoxycarbonyl, for example methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl and the like; carbobenzoxy, benzenesulfonyl and tosyl.Both amino hydrogen atoms can be substituted by a single protecting group such as, for example phthaloyl. The protecting groups are introduced in manner known per se by, for example, reaction of the amine with a lower alkanoyl or aroyl chloride, anhydride, sulfonylchloride, tert-butoxycarbonyl-oxyimino-2-phenylacetonitrile (BOC-ON), or di-tert-butyl dicarbonate ((B0C)20).

Removal of the protecting group after the required reaction has been completed can be carried out in manner known per se for the relevant protecting group. Usually, said removal will be by hydrolytic cleavage using a strong organic or mineral acid such as, for example, trifluoroacetic acid, hydrochloric acid and the like acids; or by hydrogen chloride gas under anhydrous conditions. Solvents used will be chosen dependent upon the conditions of protecting group removal. For example, ethers such as, for example, diethylether can be used for cleavage using hydrogen chloride gas.

The compounds of Formula I can be prepared in manner known per se from the corresponding hydroxyamino compound of the following general Formula Il:-

Formula II wherein p is as defined in connection with Formula I.

Preferably, the reaction proceeds via the corresponding phthalimido derivative as described below.

The amino group in the compound of Formula II will be protected in manner known per se during the reaction by a suitable subsequently removable protecting group or groups. The protecting group preferably is phthaloyl. When proceeding via the phthalimido derivative when p is 1, it is desirable to use a protecting group which does not leave any hydrogen atom on the amino group. Usually, the protecting group will be selected so that it is removed during the final step in the conversion of the compound of Formula II into the corresponding compound of Formula I.

An amino-protected derivative of a compound of Formula II can be treated with phthalimide in an anhydrous aprotic solvent in the presence of a trialkyl or triaryl-phosphine and diethylazodicarboxylate. The preferred phosphine is triphenyl-phosphine. Suitable solvents include ethers, aliphatic hydrocarbons and aromatic hydrocarbons, and tetrahydrofuran presently is the preferred solvent. Usually one to three equivalents each of phthalimide the phosphine and diethylazodicarboxylate are used per equivalent of compound of Formula II at a temperature of 100 to 1 000C for a period of 18 to 24 hours.

The phthalimido derivative can be converted into the required compound of Formula I by heating with a reactant such as hydrazine or methylamine in a polar organic solvent such as, for example, an alkanol, preferably ethanol. Preferably hydrazine hydrate is used in an amount of about 2 equivalents per equivalent of phthalimido derivative. Suitably, the conversion is performed at 500 to 100 C, preferably under reflux conditions, for a period of 3 to 24 hours.

The phthalimido derivative of Formula II also can be converted into the required compound of Formula I by heating with a strong mineral acid such as hydrochloric acid or sulfuric acid. Preferably a mixture of hydrochloric and acetic acid is used at a temperature of about 950C for about 24 hours.

Compounds of Formula II can be obtained in manner known per se from an amino-protected derivative of the corresponding epoxide of the following general Formula III:-

Formula Ill wherein p is 1 or 2.

The epoxide derivative conveniently is heated with potassium bifluoride in, for example, triethyleneglycol or with hydrogen fluoride in, for example, pyridine or dimethylformamide.

The epoxides of Formula Ill can be prepared in manner known per se from an amino-protected derivative of the corresponding aminoalkene of the following general Formula IV:

Formula IV wherein p is 1 or 2.

Conveniently, the aminoalkene derivative is treated with p-nitroperbenzoic acid in, for example, chloroform.

The aminoalkenes of Formula IV can be prepared in manner known per se from but-3-enyl bromide by, for example, the procedure described in UK Patent Specification No. 2055823A. In said procedure, the bromide is converted into a Grignard compound by, for example, treatment with magnesium turnings and then into a fluorinated methyl ketimine magnesium bromide by treatment of the Grignard compound with a fluorinated acetonitrile. The ketimine is reduced to the required compound of Formula IV by treatment with a suitable reducing agent, especially sodium borohydride.

The reaction sequence is illustrated as follows:

In the sequence above, p is 1 or 2.

Conveniently, a phthalimido amino protecting group is introduced by treating the compound of Formula IV with N-ethoxycarbonyl-phthalimide and remains throughout the reaction steps until removed, preferably by treatment with hydrazine, in the final step yielding a compound of Formula I.

The compounds of Formula II also can be obtained by reduction in manner known per se of an amino-protected derivative of the corresponding ketone of the following general Formula V:

Formula V wherein p is 1 or 2.

Preferably, the reduction is carried out using sodium cyanoborohydride.

Compounds of Formula V can be prepared in manner known per se from an amino-protected derivative of the corresponding diazoketone of the following general Formula VI:

Formula VI wherein p is 1 or 2.

Suitably, the diazoketone derivative is treated with hydrogen fluoride in, for example, pyridine or dimethyl formamide.

The compounds of Formula VI can be obtained in manner known per se from an amino-protected derivative of the corresponding aminoalkene of Formula IV above. Suitably the aminoalkene is first oxidized with, for example, potassium permanganate to form the corresponding acid which is then converted into the acid chloride by, for example, treatment with thionyl chloride. The acid chloride is treated with diazomethane to yield the required diazoketone of Formula VI. The reaction sequence is illustrated as follows:-

In the sequence above p is 1 or 2.

It will be appreciated that the order of some of the reaction steps in the process routes described above can be changed.

The compounds of Formula I exist as stereoisomers. Methods of separating the stereoisomers of a particular compound will be apparent to those skilled in the art.

The compounds produced by the foregoing processes may be isolated eitherperse or as acid addition salts thereof.

The acid addition salts are preferably the pharmaceutically acceptable, non-toxic addition salts with suitable acids such as those previously referred to in this Specification. Apart from pharmaceutically acceptable acid addition salts, other salts are also included within the scope of acid addition salts, such as for example, those with picric or oxalic acid; they may serve as intermediates in the purification of the compounds or in the preparation of other, for example, pharmaceutically acceptable, acid addition salts, or are useful for identification or characterisation of the bases.

A resulting acid addition salt may be converted into the free compound according to known methods, for example, by treating it with an alkali or alkaline earth metal hydroxide or alkoxide; with an alkali metal or an alkaline earth metal carbonate or hydrogen carbonate; with trialkylamine; or with an anion exchange resin.

A resulting acid addition salt may also be converted into another acid addition salt according to known methods; for example, a salt with an inorganic acid may be treated with a sodium, barium or silver salt of an acid in a suitable diluent, in which a resulting inorganic salt is insoluble and is thus removed from the reaction medium. An acid addition salt may also be converted into another acid addition salt by treatment with an anion exchange preparation.

The invention is illustrated by the following non-limiting Examples. All NMR measurements are given on the delta scale (i.e. tetramethylsilane=0).

Example 1 Preparation of 1 ,6-difluoro-2,5-diamino-hexane, dihydrochloride

A) I -Fluorn-2-phthalimido-5-hexene

A mixture of crude 1-fluoro-2-amino-5-hexene (11.2 g, evaluated 95.7 mmoles), Nethoxycarbonylphthalimide (20.9 g, 95.7 mmoles) in benzene (250 ml) is kept overnight at room temperature, N-Ethoxycarbonyl N1-2-(1 -fluoro-5-hexenyl)-o-phthaloyl-diamide which precipitates as white crystals is filtered off (16.1 g, 50%) NMR (CDC13+CD30D):: 1.25 (3H, t, J=7Hz), 1.45-2.45 (4H, complex m), 4.17 (2H, q, J=7Hz), N4.22 (1 H, broad m), 4.47 (2H, d of m, JH-F=47 Hz), 4.82-5.25 (2H, complex m), N5.78 (1 H, broad m), 7.65 (4H, s).

The compound described above (16.1 g, 48 mmoles) is dissolved in methylene chloride (400 ml) and treated overnight with 6.7 ml of triethylamine (48 mmoles). The solution is vigorously stirred with 200 ml of 6N HCI during 0.5 hour, separated from the acidic phase and washed several times with water. Evaporation of the organic layer affords the title compound as an oily residue which could not be crystallized. (11.8 g, quantitative.) NMR (CDCl3): 1 .67-2.60 (4H, complex m), 4.03-6.07 (1 H+2H next F+3 olefinic H, complex multiplets), 7.75 (4H, m).

B) 1-Fluoro-2-phthalimido 5,6-epoxy hexane

A mixture of 1 -fluoro 2-phthalimido-5-hexene (9.9 g, 40 mmoles) obtained as in Step A above, pnitro-per benzoic acid (9.5 g, 44 mmoles) in 300 mi of chloroform is heated for 1 5 hours under reflux.

After cooling, the mixture is filtered, the filtrate is concentrated under vacuum and chromatography on silica gel of the residue (petroleum ether/ethyl acetate: 70/30) affords the epoxide as a yellow oil (8.85 9,84%) NMR (CDCI3): 1.37-2.27 (4H, complex m), 2.43 (1 H, m), 2.70 H, m), 2.90 (1 H, m),4.00 6.27 (3H, complex m), 7.73 (4H, m).

C) 1 ,6-Difluoro-2-phthali mido-5-hydroxy-hexane

A mixture of 1 -fluoro-2-phthalimido-5,6-epoxy-hexane (8.85 g, 33.6 mmoles) obtained as in Step B above and potassium bifluoride (KHF2) (7.87 g, 101 mmoles) in triethyleneglycol (35 ml) is heated for 1.25 hours at 1 450 C, under vigorous stirring. After cooling, the reaction mixture is diluted with water and ice and extracted twice with ether. The organic phase is washed twice with water and usual work-up gives an oil containing mainly the title compound and which is used without further purification (7.3g,77%) NMR (CDCI3): 1.48 (2H, m), 2.05 (2H, m), 2.63 (1 H, -OH, s), 3.42-5.48 (6H, complex multiplets) 7.82 (4H, m).

D) I ,6-Difluoro-2,5-diphthali mido-hexane

A solution of diethylazodicarboxylate in 20 ml of dry tetrahydrofuran (THF) (7 g, 36 mmoles) is added under nitrogen to an ice-cooled solution of 1 ,6-difluoro-2-phthalimido-5-hydroxy-hexane (7.3 g, 25.8 mmoles) prepared as in Step C above, phthalimide (3.82 g, 26 mmoles) and triphenylphosphine (6.84 g, 26 mmoles) in dry THF (80 ml). The reaction mixture is kept for 2 days at room temperature and concentrated under vacuum. Two chromatographies on silica gel (petroleum ether/ethyl acetate: 50/50 and chloroform/ethyl acetate: 90/10) afford 5.86 g of 1 ,6-difluoro-2,5-diphthalimido-hexane as a white solid giving one spot on TLC (55%).

NMR (CDCl3): 1.92 (4H, m), 4.05--5.25 (6H, complex m), 7.78 (8H, broad s) Analysis for C22H'8N204F2: Calculated C 64.08; H 4.40; N 6.79 Found: C 64.02; H 4.42; N 6.80 E) I ,6-Difluoro-2,5-diamino-hexane, dihydrochloride, crude 1,6-Difluoro-2,5-diphthalimido-hexane (4.6 g, 11 mmoles) obtained as in Step D above is heated with a 1/1 mixture of acetic acid and conc. HCI (200 ml) at 11 00C for 15 hours. After concentration, 1 80 ml of conc. HCI is added to the residue and the resulting suspension is heated for 2 days at 1 1 OOC.

After cooling to room temperature, phthalic acid is removed by filtration, and the filtrate is evaporated.

The residue is dissolved in water and extracted with ether. After evaporation, the residue (approx. 3 g) is used for the next step without purification.

F) I .6-Difluoro-2.5-di-t-butoxycarbonylamino The oil obtained in Step E above (evaluated: 11 mmoles), di-t-butyl-dicarbonate (4.8 g, 22 mmoles), triethylamine (2.45 g, 24 mmoles), 1 5 ml of water and 50 ml of tetrahydrofuran are kept under stirring at room temperature for 1 5 hours. After evaporation and extraction with water and methylene chloride, usual work up affords a white solid (approx. 5 g) which is chromatographed on silica gel (chloroform/ethyl acetate: 95/5). Two main sets of fractions are obtained: one evidenced on TLC in a less polar but very similar compound to the title compound (perhaps an isomer) (570 mg) and one evidenced in the title compound but still slightly contaminated by the above impurity (2.80 g) (yield with the isomer: 73%).

Carefully chromatography on silica gel of 500 mg of the purest portion (ether/petroleum ether: 25/75) affords 200 mg of pure 1 ,6-difluoro 2,5-di-t-butoxycarbonylamino-hexane (at the limit of ninhydrine detection on TCL), which is crystallized from chloroform/petroleum ether in two successive batches (60 mg and 50 mg) NMR (CDCI3): 1.42 (18H, s), 1.58 (4H, m), 3.78 (2H, d of broad m, J ~ 26 Hz), 4.38 (4H, d of d, JH-F=48 Hz, H-H=3 Hz).

G) 1 ,6-Difluoro-2,5-diamino-hexane, dihydrochloride 1 ,6-Difluoro-2,5-di-t-butoxycarbonylamino-hexane (60 mg crystals, 0.17 mmole) obtained in Step F above is dissolved in 10 ml of dry ether saturated with HCI gas and kept under stirring at room temperature for 2 days. The solid obtained by filtration is washed with dry ether and dried under oil vacuum (30 mg, 78%).

NMR (D2O/DCI): 6 (external standard TMS) 2.13 (4H, m), 3.73 (2H, d of broad m, J=24 Hz), 4.77 (4H, d of m, JH~F=46 Hz) Analysis for C6H14N2F . 2HCI: Calculated C 32.01; H 7.16; N 12.44 Found C 31.76; H 6.76; N 12.40 Similar treatment on the second batch of 1,6-difluoro 2,5-di-t-butoxycarbonylamino-hexane (50 mg, 0.14 mmole) from Step F above affords 1 5 mg of the title compound (47%).

GC analysis on a chirasil-val column of the two batches of 1 ,6-difluoro-2,5-diamino-hexane, dihydrochloride as their TFA derivatives, shows that the first one corresponds to the meso diastereoisomer (99%) and the second to a mixture of the meso (46%), R,R (27%) and S,S (27%) diastereoisomers.

In the following Examples relating to pharmaceutical compositions, the term "active compound" is used to indicate the compound 1 ,6-difluoro-2,5-diamino-hexane. This compound may be replaced in these compositions by any other compound of the invention, for example by 1,1 ,6-trifluoro-2,5- diamino-hexane. Adjustments in the amount of medicament may be necessary or desirable depending upon the degree of activity of the medicament as is well known in the art.

Example 2 An illustrative composition for hard gelatin capsules is as follows:- (a) active compound 20 mg (b) talc 5 mg (c) lactose 90 mg The formulation is prepared by passing the dry powders of (a) and (b) through a fine mesh screen and mixing them well. The powder is then filled into hard gelatine capsules at a net fill of 11 5 mg per capsule.

Example 3 An illustrative composition for tablets is as follows:- (a) active compound 20 mg (b) starch 43 mg (c) lactose 45 mg (d) magnesium stearate 2 mg The granulation obtained upon mixing the lactose with the compound (a) and part of the starch and granulated with starch paste is dried, screened, and mixed with the magnesium stearate. The mixture is compressed into tablets weighing 110 mg each.

Example 4 An illustrative composition for an injectable suspension is the following 1 ml ampul for an intramuscular injection: Weight per cent (a) active compound 1.0 (b) polyvinylpyrrolidone 0.5 (c) lecithin 0.25 (d) water for injection to make 100.0 The materials (a)-(d) are mixed, homogenized, and filled into 1 ml ampuls which are sealed and autoclaved 20 minutes at 121 OC. Each ampul contains 10 mg per ml of novel compound (a).

Example 5 Mg/suppository Active Compound 50 Oil of Theobroma 950 The medicament is powdered and passed through a B.S. No.100 sieve and triturated with molten oil of Theobroma at 450C to form a smooth suspension. The mixture is well stirred and poured into moulds each of nominal 1 G capacity, to produce suppositories.

Example 6 The ODC inhibitory activity of the compounds of Formula I can be demonstrated in vivo according to the following procedure: Male rats of the Sprague-Dawley strain (200-220 g body weight), purchased from Charles River, are given food and water ad libitum under a constant 12 hr light-l 2 hr dark lighting schedule.

Drugs are injected intraperitoneally (dissolved in 0.9% saline) or are given by gavage (dissolved in water). Rats given saline or water serve as control. Five to six hours after drug administration, the animals are killed by decapitation and the ventral prostate and thymus are excised rapidly and immediately processed. The tissues are homogenized with three volumes of 30 mM sodium phosphate buffer (pH 7.1) containing 0.1 mM EDTA, 0.25 M sucrose, 0.1 mM pyridoxal phosphate and 5 mM dithiothreitol. Ornithine decarboxylase activities are determined on a 1000 g supernatant of prostate homogenate and on a whole thymus homogenate, essentially as described by Ono et al (Biochem.

Biophys. Acta, 284, 285 (1972)).

Example 7 The activity of the compounds of Formula I as inhibitors of ornithine decarboxylase (ODC) can be demonstrated in vitro according to the following procedure: Ornithine decarboxylase (ODC) is prepared from the livers of rats which have been injected with thioacetamide (150 mg/kg of body weight) 18 hrs before sacrifice, and is purified about ten fold by acid treatment at pH 4.6 as described by Ono et al (Biochem. Biophys. Acta 284, 285 (1972)). The stock solution of ODC is comprised of protein (16 mg/mL), sodium phosphate buffer (30 mM, pH 7.1), dithiothreitol (5 mM) and pyridoxal phosphate (0.1 mM). The specific activity of this stock solution is 0.12 nmol of Cumin per mg of protein.For a typical experiment 320y1 of this stock solution are mixed at time 0 with 80,ul of a solution of the inhibitor in water and incubated at 370. At different times 50y1 aliquots are transferred into a 1-mL assay medium containing sodium phosphate (30 mM, pH 7.1), dithiothreitol (5 mM), pyridoxal phosphate (0.1 mM), L-ornithine (0.081 ymol), and DL-[1 -'4C] ornithine (0.043mol, 58 Ci/mol, Amersham) in a closed vessel in which a filter paper moistened with 50y1 hyamine hydroxide (1 M) is fitted. The reaction is allowed to proceed for 60 min at 370C and then terminated by addition of 0.5 ml of 40% trichloroacetic acid. After an additional 30 min the CO2 absorbed on the filter paper is counted in a standard scintillation cocktail. K, (apparent dissociation constant) and T50 (half-life, at infinite concentration of inhibitor are calculated according to the method of Kitz and Wilson (J. Biol. Chem., 237, 3245 (1962)).

When tested according to the above-described procedure, the compound of Example 1 gave the results drawn below. Half life (t112) at 10 M is also set forth below.

K,( m) zsO(min) ta,2(min) 7200 9 > 200

Claims (11)

Claims

1. A fluorinated alkylene diamine derivative of the following general Formula I:

Formula I wherein p represents 1 or 2 or a pharmaceutically acceptable salt thereof.

2. 1 ,6-Difluoro-2,5-diamino-hexane or a pharmaceutically acceptable salt thereof.

3. 1,1 ,6-Trifluoro-2,5-diamino-hexane or a pharmaceutically acceptable salt thereof.

4. A compound as claimed in any one of the preceeding Claims for use in a method of treatment of the human or animal body by therapy or of diagnosis practiced on the human or animal body.

5. A compound as claimed in any one of the preceding Claims for use in the inhibition in the human or animal body of ornithine decarboxylase.

6. A pharmaceutical composition comprising a compound as claimed in any one of the preceding Claims in admixture or otherwise in association with a pharmaceutically acceptable carrier or diluent therefor.

7. A pharmaceutical composition as claimed in Claim 6 in unit dosage form containing 10 mg to 500 mg of said compound per unit dose.

8. A method of preparing a compound as claimed in Claim 1 which comprises treating a hydroxyamine of the following general Formula II:

Formula II wherein p is as defined in Claim 1; in the form of a derivative thereof in which the amino group is protected by a subsequently removable blocking group or groups, in manner known per se to convert the hydroxy group into an amino group and, if necessary, subsequently removing the blocking group or groups.

9. A method as claimed in Claim 8 wherein the said hydroxyamine is treated with phthalimide in an anhydrous aprotic solvent in the presence of a trialkyl or triaryl-phosphine and diethylazodicarboxylate to form the corresponding phthalimido derivative, which is hydrolytically cleaved using a strong mineral acid or reaction with hydrazine or methylamine.

10. A method as claimed in Claim 8 and substantially as hereinbefore described in Example 1.

11. A compound as claimed in any one of Claims 1 to 5 whenever prepared by a method as claimed in any one of Claims 8 to 10.