NO179614B - Analogous Process for Preparing Therapeutically Active 2-Formylbenzylphosphonic Acid Derivatives - Google Patents

Abstract

The compound of the formula I <IMAGE> in which R represents an aldehyde group or a group which can be converted into an aldehyde, R<1> and R<2> represent alkyl, alkenyl, alkynyl, aralkyl, cycloalkyl, hydrogen, sodium, potassium, calcium, magnesium, aluminium, lithium, ammonium or triethylammonium or R<1> and R<2> together form a cyclic diester, R<3> and R<4> represent alkyl, alkenyl, alkynyl, cycloalkyl, hydrogen, alkoxy or halogen, R<5> and R<8> represent alkyl, alkenyl, alkynyl, aralkyl, cycloalkyl, alkoxy, phenyl, cyanide, hydroxyl or hydrogen, X, Y or Z represent oxygen or sulphur, or prodrug forms of the compound of the formula I can be used for treatment of diseases caused by viruses. The preparation of these compounds and pharmaceutical preparations which contain them and also their use are described.

Description

The invention relates to an analog manufacturing method

of new therapeutically active 2-formylbenzylphosphonic acid derivs.

Until now, various preparations have been used to treat diseases caused by viruses, such as e.g. nucleoside analogues, amantadine, pyrophosphate analogues or immunomodulators (M.J. Wood, A.M. Geddes, The Lancet, 1987, 1189). Some phosphonic acid derivatives are known to show antiviral activity. These include compounds such as phosphoformic acid (PFA), phosphoacetic acid (PAA), methylenediphosphonic acid (MDP), as well as tetrazolephosphonic acids (S.M. Roberts, NATO ASI Ser., Ser. A 143, 1988, 37; D.W. Hutchinson, M. Naylor , Nucleic Acids Res., 13, 1985, 8519). PFA has a broad antiviral spectrum, but causes some toxic side effects that have until now prevented development into an antiviral drug (M.J. "Wood, A.M. Geddes, The Lancet, 1987, 1189). Of orthophosphonyloxyacetophenone derivatives, it is known that they are particularly effective against Picorna virus (EP 21,000).

Diana et al. (J. Med. Chem. 27, 1984, 691; DOS 29 22 054) describes a class of compounds of the type

where A is an aromatic ring and C is a phosphonate or a B-keto-phosphonate, whereby A and C are separated from each other by a bridge of 3-8 methylene groups (B). From this class of compounds, the arylalkylphosphonic acids with a methylene bridge of more than 5 carbon atoms show antiviral activity against herpes viruses.

However, arylalkylphosphonic acids with methylene bridges smaller than 5 carbon atoms show no antiviral activity. The substitution of the aromatic residues in these compounds takes place according to Diana et al. essentially by a 2-chloro, 4-methoxy or 4-carbethoxyphenoxy group.

Benzylphosphonic acids have so far not been described as effective antiviral compounds (J.C.H. Mao et al., Antimicrob. Agents Chemother, 27, 1985, 197).

It has now surprisingly been found that 2-formylbenzylphosphonic acid derivatives exhibit antiviral activity.

The invention thus relates to an analogue method for the preparation of a therapeutically active compound of formula

IN.

R<*> and R**, which may be the same or different, represent a straight-chain or branched alkyl group of 1 to 20 carbon atoms, a straight-chain or branched alkenyl or alkynyl group of 2 to 20 carbon atoms, an aralkyl group of 7 to 20 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms, hydrogen, sodium, potassium, calcium, magnesium, aluminum lithium, ammonium or triethylammonium, or R<1 >and R^ together form a cyclic diester of 2 to 6 carbon atoms in the ring ,

R<3> and R<*>, which may be the same or different, represent a straight-chain or branched alkyl group of 1 to 20 carbon atoms, a straight-chain or branched alkynyl or alkenyl group of 2 to 20 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, hydrogen, fluorine, chlorine, bromine or iodine, r5 , r6 , r<7> and r<8> jjan be week or different, stand for a straight-chain or branched alkyl group with 1 to 20 carbon atoms, a straight-chain or branched alkenyl or alkynyl group of 2 to 20 carbon atoms, an aralkyl group of 7 to 20 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, hydrogen, fluorine, chlorine, bromine, iodine, a cyanide, hydroxy or phenyl group or represents the residue of formula Ia,

R<1>^ stands for a straight-chain or branched alkyl group with 1 to 20 carbon atoms, a straight-chain or branched alkenyl or alkynyl group with 2 to 20 carbon atoms, an aralkyl group with 7 to 20 carbon atoms, a cycloalkyl group with 3 to 8 carbon atoms, hydrogen, sodium, potassium, calcium, magnesium, aluminium, lithium, ammonium or triethylammonium, and

X, Y and Z can be the same or different, standing for oxygen or sulphur.

It is preferred to have a compound of formula I there

R<1> and R<2> stand for an alkyl group with 1 to 10 carbon atoms, an alkenyl or alkynyl group with 2 to 10 carbon atoms, hydrogen or an aralkyl group with 7 to 16 carbon atoms,

R<3> and R<4> stand for an alkyl group with 1 to 4 carbon atoms, an alkenyl or alkynyl group with 2 to 4 carbon atoms or hydrogen,

R<5>, r6 , R<7> and R<**> stand for chlorine, bromine, methoxy or hydrogen, and

X, Y and Z stand for oxygen.

The term alkyl group with 1 to 10 carbon atoms means e.g. the following residues: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, 2,2-dimethyl-1-propyl, n-pentyl, n-hexyl, n-heptyl, n-octyl , n-nonyl and n-decyl. The term alkenyl group with 2 to 10 carbon atoms means e.g. the following compounds: ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl or decenyl. The term alkynyl group with 2 to 10 carbon atoms means e.g. the following compounds: ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptinyl, noninyl, octynyl or decinyl. An aralkyl group with 7 to 16 carbon atoms means e.g. the following residues: phenylmethyl, phenylethyl, phenylbutyl, phenylpropyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl or phenyldecyl. A cycloalkyl group with 3 to 8 carbon atoms means residues such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl. Alkoxy groups with 1 to 4 carbon atoms are residues such as methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec-butoxy or tert-butoxy.

More specifically, the invention relates to an analogue method for the production of a therapeutically active compound of formula (I), where the method is characterized by the fact that a compound of formula II:

there

R3, R4, R5, R<6>, R<7> and R<8> have meanings as indicated above

and

T stands for chlorine, bromine, iodine, methylsulfonate, phenylsulfonate or tosylsulfonate,

is reacted with a compound of formula III,

there

R<1> and R<2> have meanings as indicated above,

R^ stands for a straight-chain or branched alkyl group with 1 to 4 carbon atoms, and

X, Y and Z, which may be the same or different, stand for oxygen or sulphur.

The preparation of the compound of formula I takes place by reacting the compound of formula II with the compound of formula III suitably at temperatures between 100 and 250°C, preferably between 120 and 180° (US 4,299,615; Houben-Weyl, Methoden der Org. Chemie , Vol. XII/1, page 423, Thieme-Verlag, Stuttgart; Houben-Weyl, Methoden der Org. Chemie, Vol. E2, page 300). The reaction can take place in a suitable solvent, such as hexamethylphosphoric acid amide (EMPA), dimethylylformamide (DMF), dimethyl sulfoxide (DMS0), N,N'-dimethyl-N,N'-propylene urea (DMPU) or N,N'-dimethyl-N, N'-ethylene urea (DMEU). The reaction can also be carried out without a solvent. The purification takes place according to generally common methods, preferably by chromatography on silica gel with a suitable eluent, by distillation or by recrystallization from suitable solvents. The compounds of formula II and III can be prepared in a manner known per se. The transfer of the phosphonic acid diester into their monoesters, as well as the corresponding free acids or their salts, takes place e.g. by boiling with dilute hydrochloric acid (Houben-Weyl, Methoden der Organischen Chemie, Vol. XII/1, 1963), or by reaction with trimethylbromosilane (CE. McKenna, J. Schmidhauser, J.C.S. Chem. Commun., 1979, 739). The purification takes place by recrystallization in suitable solvents or by chromatographic methods, preferably by ion exchange chromatography with suitable eluents. By ion exchange chromatography, the desired salt forms can also be obtained.

An effectiveness test of chemotherapeutics for HIV infections in humans entails difficulties, as no infection model yet exists in the laboratories. To test chemotherapy, the infection must also be tested with other retro-viruses. In these cases, the infection of mice with Friend leukemia virus is selected. Also, normal NMRI (Naval Medical Research Institute) laboratory mice are infected by intravenous injection with Friend leukemia virus-containing mouse serum. In the untreated control animals, infection develops as a symptom within 2 weeks with a significant enlargement of the spleen and liver. The treatment takes place over 10 days, and begins 48 hours after the infection. On the 14th day of the experiment, the animals are killed and opened. The spleen is removed and weighed. As measurement parameters, the therapeutic effect as weight of spleen in the treated animals is put in relation to the untreated infection controls.

In uninfected full-grown laboratory mice (20-24 g body weight), the spleen weighed approx. 1% of body weight or less, while in infected animals the spleen reached approx. 10$ of the body weight.

The compound of formula I possesses valuable pharmacological properties, in particular an antiviral effect both against diseases caused by DNA and RNA viruses, in particular against diseases caused by herpes simplex virus (HSV I), Myxo virus, Friend leukemia virus (FLV) or human immunodeficiency virus (HIV). The compounds according to the invention are therefore suitable for combating various diseases caused by viruses, such as diseases of the respiratory system, diseases of the skin, eyes, central nervous system, AIDS and AIDS-altered conditions, such as AIDS-altered complexes (AEC), generalized lymphadenopathie (PGL ), AIDS changes, neuralgic conditions (such as mental weakness or tropical paraparesis), anti-HIV antibody-positive conditions, Kaposi-Sarcoma or thrombopenic purpura.

The compounds of formula I can either be used alone or mixed with physiologically acceptable excipients or carriers in effective amounts as pharmaceuticals. They can e.g. be administered orally at a dose of 1 to 500 mg/kg/day, preferably 5 to 50 mg/kg/day. Application for parenteral, rectal or topical application or as an aerosol takes place e.g. in an amount of from 0.5 to 500 mg/kg/day, preferably with 2 to 100 mg/kg/day. The compounds of formula I can be conveniently administered in dosage units containing at least the effective amount of the compounds according to the invention, preferably 25 to 6000 mg, particularly preferably 100 to 1000 mg. These values refer to an adult human weighing 75 kg. These dosage units can also be administered several times per day. The dosage can be increased in difficult cases. In many cases, however, lower amounts are not enough. The following are particularly suitable for combating diseases caused by RNA or DNA viruses: 2-formylbenzy1phosphonic acid diethyl ester,

2-formylbenzylphosphonic acid ditriethylammonium salt, 2-formylbenzylphosphonic acid monoethyl ester triethylammonium salt.

The compounds of formula I produced according to the invention can also be administered in combination with other substances, in particular antiviral agents and immune stimulators, such as interferons. The compounds of formula I are hereinafter referred to as active substances.

Medicines comprising compounds of general formula (I) can be prepared according to methods known per se within the field. As medicines, the active substance is either used as such or preferably in combination with suitable pharmaceutical excipients or carriers in the form of tablets, dragées, capsules, suppositories, emulsions, suspensions or solutions, whereby the active substance content is up to approx. 95/6, advantageously between 10 and 75%.

Suitable auxiliary or carriers for the desired drug formulations are e.g. in addition to solvents, builders, suppository bases, tablet excipients and other active substances, also applicable with antioxidants, dispersants, emulsifiers, foamers, flavor correctors, preservatives, solubilizers and dyes.

The active ingredient can be used orally, parenterally, intravenously or rectally, where, in addition to oral use, intranasal use as an aerosol is particularly preferred.

For an oral form of application, the active ingredient is mixed with the suitable additives such as carriers, stabilizers or inert diluents and via usual methods brought into suitable administration forms, such as tablets, dragees, suppositories, aqueous or oily solutions. As inert carrier substances, it can e.g. be used gum arabic, magnesia, magnesium carbonate, potassium phosphate, milk sugar, glucose or starch, especially corn starch. The preparation can take place both as drying and as moisturizing granules. As oily carriers and solvents are e.g. plant and animal oils relevant, such as sunflower oil or cod liver oil.

For subcutaneous or intravenous use, the active ingredient is brought into solution, suspension or emulsion with the appropriate substances such as solubilizers, emulsifiers or further auxiliaries. As a solvent, e.g. physiological saline solution, alcohols, e.g. ethanol. propanol, glycerin, sugar solution such as glucose or mannitol solution or a mixture of appropriate solvents.

The following examples serve to further explain the invention.

Example 1

Preparation_of_2=formylb 47.9 g (0.31 mol) of 2-chloromethylbenzaldehyde are heated to 160°C together with 51.5 g (0.31 mol) of triethylphosphite. Thus ethyl chloride distills off. The product was purified by fractional distillation.

Yield: 64.5 g (81%); bp: 130°C/0.3 mm;

1H-NMR (270 MHz, CDCl3/TMS): S = 1.23 (t, 6E, P-0-CH2-CH3), 3.78 (d, 2H, CH2-P) JP-H = 24 Hz, 4.04 (dq, 4H, P-O-CH2-CH3), 7.19-7.97 (m, 4H, Ar-H).

Example 2

Preparation of 2-formylbenzylphosphonic acid ditriethylammonium salt (B) and 2-formylbenzylphosphonic acid monoethyl ester triethyl-§™??25i<ym>§§15_l^i 5.0 g (20 mmol) of 2-formylbenzylphosphonic acid diethyl ester is mixed with 100 ml of 6 M HC1 and refluxed for 6 hours. Water and HCl are distilled off in vacuum, and coevaporated three times with toluene. The remaining brown mass is chromatographed over silica gel (C₂C₂/methanol/triethylamine 75/24/1). Compounds B and C are obtained as oily products. They can be separated by chromatography on diethyl-aminoethyl-®Sephadex A25 (Et3NH<+->form, Pharmacia, Freiburg, BED). They differ in their running conditions (Ef value). The elution takes place with a triethylammonium bicarbonate gradient from 0.3-1.0 M. (9): Rf = 0.1; Yield: 2.4 g (30%); 1HNHR (270 MHz, DMSO/TMS): δ = 1.07 (t, 18H, N-CH2-CH3), 2.86 (g, 12H, N-CH2-CH3), 3.23 (d, 2E, CH2-P) JP-E=23 Hz, 7.24-7.78 (m, 4H, Ar-H), 10.31 (s, 1H, CHO). (C): R f = 0.3; Yield: 1.4 g (21%); 1HNMR (270 MHz, DM50/TMS): S = 1.01-1.17 (m, 12H, N-CH2-CH3 & P-0-CH2-CH3),

2.88 (g, 6H, N-CH2-CH3), 3.27 ((d, 2H, CH2-P) JP-H 23 Hz, 3.68 ((dq, 2H, P-0-CH2-CH3 ), 7.18-7.78 (m, 4H, Ar-H), 10.31 (s, 1H, CHO).

Example 3

Preparation of 2-formylbenzylphosphonic acid-ditriethylammonium salt_(B)

To 2.0 g (8 mmol) of compound A in 10 ml of absolute dioxane, 3.2 g (21 mmol) of trimethylsilyl bromide is added dropwise, the reaction mixture is heated to 50°C and stirred for 6 hours at this temperature. It is evaporated, mixed several times with water and lyophilized. The crude product is purified by chromatography as in example 2.

Yield: 1.98 g (62%).

Medical trials

Attempt 1

Pathogen-free NMRI mice with a weight of approx. 15 g are infected intraperitoneally with Herpes simplex type 1 and then treated with therapy with the compounds mentioned in table 1 intraperitoneally, orally or subcutaneously. The treatment takes place twice a day over 2.5 days, and begins after the infection. The course of treatment is determined on the basis of the course of the disease and the survival rate in relation to untreated infection controls. The controls received, instead of the compounds to be investigated, a water-soluble methylhydroxyethyl cellulose (viscosity 300 Pa*s in a 2% solution applied). The experiments are carried out with groups of 5 mice each per preparation.

The chemotherapeutic effects of compound A are evident from Table 1.

Attempt 2

Cell cultures of Hela and Vero cells are transferred into microtiter plates and infected with Myxo virus (influenza A2). 2 hours after the infection, compounds B and C are added to the infected cell cultures in different dilutions. 48 to 72 hours after infection, the course of therapy is determined microscopically and after neutral red absorption (color test according to Finter) photometrically on the basis of cytopathogenic effect (Finter, N.B. Interferons, 1966). The minimal concentration at which approximately half of the infected cells did not show any cytopathogenic effect is considered the minimal inhibitory concentration (MIC). The results are summarized in table 2.

Attempt 3

Pathogen-free NMRI mice with a weight of approx. 16 g are infected intranasally with influenza A2 and then subcutaneously and orally treated with the compounds mentioned in Table 3. The compounds were applied to the animals under light ether anesthesia with a drop of virus suspension in the nasal opening. The treatment took place twice a day over 2.5 days, and began after the infection. As a comparison, amantadine was used. The course of treatment was determined on the basis of the course of the disease and the survival rate in relation to untreated infection controls. Instead of the compounds to be tested, the controls had a water-soluble methylhydroxyethyl cellulose applied (viscosity 300 Pa*s in 2% solution). The experiments were carried out with groups of 5 mice per preparation.

The chemotherapeutic effects appear in table 3.

Attempt 4

Laboratory mice (NMRI, female, weight 20-24 g) were intravenously infected with Friend leukemia virus (FLV)-containing mouse serum. 48 hours after infection, treatment began. During 10 days, the mice are treated with the specified substances in table 4. Once per day, the specified substances are administered orally or intraperitoneally. 14 days after infection, the animals are killed by dislocation and the spleen is removed. The weight of the spleen is determined. As a target parameter for therapeutic effect, the spleen weight of the animals treated with compound A is compared to the untreated infection controls.

Suramin and azidothymidine (AZT) served as standard substances. The effects of the preparations appear from table 4.

Claims (1)

Analogous process for the preparation of a therapeutically active compound of formula (I), where R<1> and R<2>, which may be the same or different, represent a straight chain or branched alkyl group with 1 to 20 carbon atoms, a straight chain or branched alkenyl or alkynyl group with 2 to 20 carbon atoms, an aralkyl group with 7 to 20 carbon atoms, a cycloalkyl group with 3 to 8 carbon atoms, hydrogen, sodium, potassium, calcium, magnesium, aluminium, lithium, ammonium or triethylammonium, or R<1> and R<2> together form a cyclic diester with 2 to 6 carbon atoms in the ring, R<3> and R<4>, which may be the same or different, represent one straight chain or branched alkyl group with 1 to 20 carbon atoms, a straight chain or branched alkynyl or alkenyl group with 2 to 20 carbon atoms, a cycloalkyl group with 3 to 8 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, hydrogen, fluorine, chlorine, bromine or iodine, R5, R6, R<7> and R<8> may be the same or different, represent a straight chain or branched alkyl group of 1 to 20 carbon atoms, a straight or branched alkenyl or alkynyl group of 2 to 20 carbon atoms, an aralkyl group of 7 to 20 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, hydrogen , fluorine, chlorine, bromine, iodine, a cyanide, hydroxy or phenyl group or represents the residue of formula (Ia), R<19> stands for a straight-chain or branched alkyl group with 1 to 20 carbon atoms, a straight-chain or branched alkenyl or alkynyl group with 2 to 20 carbon atoms, an aralkyl group with 7 to 20 carbon atoms, a cycloalkyl group with 3 to 8 carbon atoms, hydrogen, sodium , potassium, calcium, magnesium, aluminium, lithium, ammonium or triethylammonium and X, Y and Z which may be the same or different, stand for oxygen or sulphur, characterized in that the compound of formula (II): where R<3>, R<4>, R<5>, R<6>, R<7> and R<8> have the meaning as indicated above, and T stands for chlorine, bromine, iodine, methylsulfonate, phenylsulfonate or tosylsulfonate, is reacted with the compound of formula (III): there R<1>, R<2>, X, Y and Z have meanings as indicated above, and R^ stands for a straight-chain or branched alkyl group with 1 to 4 carbon atoms.