Substituted pyrimidine compounds and the use thereof

This is a Divisional application of application Ser. No. 08/765,292, filed on Jan. 14, 1997, under Section 371 which is U.S. Pat. No. 6,342,604

The invention relates to substituted pyrialidine compounds and to the use of such compounds. Said compounds have valuable therapeutic properties and can be used in particular to treat disorders which respond to dopamine D 3 ligands.

Compounds which are of the type under discussion here and have physiological activity have in some cases been disclosed. Thus, DE 21 39 082 and DE 22 58 561 describe pyrimidine derivatives and pyrimidone derivatives with basic substituents as drugs for lowering blood pressure. These pyrimidine and pyrimidone derivatives have the formulae:

where in (A) X is, inter alia, sulfur, A is C 1 -C 6 -alkylene, and R 1 , R 2 , R 3 and Z are various substituents. In (B), X and Y are each oxygen or sulfur, A is C 2 -C 6 -alkylene and R and Z are various substituents.

Neurons receive their information inter alia via G protein-coupled receptors. There are numerous substances which exert their effect via these receptors. One of them is dopamine.

Confirmed findings on the presence of dopamine and its physiological function as neurotransmitter have been published. Cells which respond to dopamine are connected with the etiology of schizophrenia and Parkinson's disease. These and other disorders are treated with drugs which interact with dopamine receptors.

By 1990, two subtypes of dopamine receptors had been clearly defined pharmacologically, namely D 1 and D 2 receptors.

Sokoloff et al., Nature 1990, 347: 146-151, found a third subtype, namely D 3 receptors. They are expressed mainly in the limbic system. The D 3 receptors differ structurally from the D 1 and D 2 receptors in about half the amino-acid residues.

The effect of neuroleptics has generally been ascribed to their affinity for D 2 receptors. Recent receptor-binding studies have confirmed this. According to these, most dopamine antagonists, like neuroleptics, have high affinity for D 2 receptors but only low affinity for D 3 receptors.

We have now found, surprisingly, that certain pyrimidine compounds have a high affinity for the dopamine D 3 receptor and a low affinity for the D 2 receptor. They are thus selective D 3 ligands.

The present invention therefore relates to the use of pyrimidine compounds of the general formula I:

where

A is C 1 -C 18 -alkylene which may comprise at least one group selected from O, S, NR 4 , CONR 4 , NR 4 CO, COO, OCO and a double or triple bond,

B is

R 1 , R 2 , R 3 are selected, independently of one another, from H, halogen, OR 4 , NR 4 R 5 , SR 4 , CF 3 , CN, CO 2 R 4 and C 1 -C 8 -alkyl which is unsubstituted or substituted by OR, OC 1 -C 8 -alkyl or halogen,

R 4 is H, C 1 -C 8 -alkyl which is unsubstituted or substituted by OR, OC 1 -C 8 -alkyl or halogen,

R 5 has the meanings indicated for R 4 or is COR 4 or CO 2 R 4 ;

Ar is phenyl, pyridyl, pyrimidyl or triazinyl, where Ar may have from one to four substituents which are selected, independently of one another, from OR 5 , C 1 -C 8 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, halogen, CN, CO 2 R 4 1 , NO 2 , SO 2 R 4 , SO 3 R 4 , NR 4 R 5 , SO 2 NR 4 R 5 , SR 4 , CF 3 , CHF 2 , a 5- or 6-membered carbocyclic aromatic or non-aromatic ring and a 5- or 6-membered heterocyclic aromatic or non-aromatic ring having 1 to 3 hetero atoms which are selected from O, S and N, where the ring may be unsubstituted or substituted by C 1 -C 8 -alkyl, Hal, OC 1 -C 8 -alkyl, OH, NO 2 , CF 3 , and where Ar may also be fused to a carbocyclic or heterocyclic ring of the type defined above, and the salts thereof with physiologically tolerated acids for producing a pharmaceutical composition for treating disorders which respond to dopamine D 3 receptor antagonists or agonists.

The invention also relates to the pyrimidine compounds of the formula I′

where

A, B, Ar, R 1 , R 2 and R 3 have the meanings stated in claims 1 to 8 , and the salts thereof with physiologically tolerated acids, excepting the compounds of the formula

where R 1 is OH or SH, R 2 and R 3 are, independently of one another, H, C 1 -C 8 -alkyl, OC 1 -C 6 -alkyl, SC 1 -C 6 -alkyl, CO 2 H, OH, SH, NR 4 R 5 or halogen, where R 4 and R 5 are H or C 1 -C 6 -alkyl, A is SC 1 -C 6 -alkylene, NHC 1 -C 6 -alkylene or N(C 1 -C 6 -alkyl)-C 1 -C 6 -alkylene, B is

and Ar is phenyl

which may have one or more substituents selected from C 1 -C 4 -alkyl, OC 1 -C 4 -alkyl, SC 1 -C 4 -alkyl, NO 2 , CF 3 , F, Cl or Br.

The compounds used according to the invention are selective dopamine D 3 receptor ligands which intervene regioselectively in the limbic system and, because of their low affinity for the D 2 receptor, have fewer side effects than classical neuroleptics, which are D 2 receptor antagonists. The compounds can therefore be used to treat disorders which respond to dopamine D 3 receptor antagonists or agonists, eg. for treating disorders of the central nervous system, in particular schizophrenia, depression, neuroses and psychoses. They can additionally be used to treat sleep disorders and nausea and as antihistamines.

Within the scope of the present invention, the following terms have the meanings indicated below: alkyl (also in radicals such as alkoxy, alkylamino, etc.) means a straight-chain or branched alkyl group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms and, in particular, 1 to 4 carbon atoms. The alkyl group can have one or more substituents which are selected, independently of one another, from OH and OC 1 -C 8 -alkyl.

Examples of an alkyl group are methyl, ethyl, n-propyl, i-propyl, n-butyl, isobutyl, t-butyl, etc.

Alkylene stands for straight-chain or branched radicals having, preferably, 2 to 15 carbon atoms, particularly preferably 3 to 10 carbon atoms.

The alkylene groups may comprise at least one of the abovementioned groups. This can—just like the double or triple bond mentioned—be arranged in the alkylene chain at any point or at the end of the chain so that it connects the chain to the pyrimidine residue. The latter is preferred. When the alkylene group comprises a double or triple bond, it has at least three carbon atoms in the chain.

Halogen is F, Cl, Br, I and, in particular, Cl, Br, I.

R 1 , R 2 and R 3 are preferably, independently of one another, H, C 1 -C 8 -alkyl, NR 4 R 5 , SR 4 or OR 4 , where R 4 and R 5 are, independently of one another, H or C 1 -C 8 -alkyl.

Ar can have one, two, three or four substituents, preferably one or two substituents, which are in each case in the m position. They are preferably selected independently from halogen, CF 3 , CHF 2 , CN, NO 2 , OR 4 , NR 4 R 5 , C 1 -C 8 -alkyl, OC 1 -C 8 -alkyl, phenyl and SR 4 , where R 4 and R 5 are H or C 1 -C 8 -alkyl. If one of the substituents is C 1 -C 8 -alkyl, a branched group and, in particular, isopropyl or t-butyl is preferred.

Ar preferably has at least one substituent and is, in particular,

where D 1 , D 2 and D 3 are, independently of one another, CR or N, and R, S and Y are H or have the meanings indicated above or below.

Ar is preferably unsubstituted or substituted phenyl, 2-, 3- or 4-pyridinyl or 2-, 4(6)- or 5-pyrimidinyl.

When one of the substituents of the radical Ar is a 5- or 6-membered heterocyclic ring, examples thereof are a pyrrolidine, piperidine, morpholine, piperazine, pyridine, 1,4-dihydropyridine, pyrimidine, triazine, pyrrole, thiophene, thiazole, imidazole, oxazole, isoxazole, pyrazole or thiadiazole residue.

When one of the sustituents of the radical Ar is a carbocyclic radical, it is, in particular, a phenyl, cyclopentyl or cyclohexyl radical.

When Ar is fused to a carbocyclic or heterocyclic radical, it is, in particular, a naphthalene, di- or tetrahydronaphthalene, quinoline, di- or tetrahydroquinoline, indole, dihydroindole, benzimidazole, benzothiazole, benzothiadiazole, benzopyrrole or benzotriazole residue.

A preferred embodiment comprises the compounds of the formula I where A is C 1 -C 10 -alkylene which may comprise at least one group selected from O, S, NR 3 , cyclohexylene and a double or triple bond.

Another preferred embodiment comprises use of the compounds of the formula I where R 1 , R 2 and R 3 are, independently of one another, H, C 1 -C 8 -alkyl which can be unsubstituted or substituted by OH, OC 1 -C 8 -alkyl or OH [sic], or OH, OC 1 -C 8 -alkyl, SR 4 or NR 4 R 5 , where R 4 and R 5 are, independently of one another, H or C 1 -C 8 -alkyl;

Ar is phenyl, pyridyl or pyrimidyl which may have one, two, three or four substituents selected from H. C 1 -C 8 -alkyl which may be substituted by OH, OC 1 -C 8 -alkyl or halogen, or OR 4 where R 4 is , C 1 -C 8 -alkyl which may be substituted by OH, OC 1 -C 8 -alkyl or halogen, or CHF 2 , CF 3 , CN, halogen, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, C 1 -C 6 -cyclohexyl [sic], phenyl, naphthyl and a 5- or 6-membered heterocyclic aromatic radical with 1 to 3 hetero atoms selected from O, N and S.

Another preferred embodiment comprises use of the compounds of the formula I where B is

Another preferred embodiment is the use of the compounds of the formula I where Ar is phenyl which has one to four substituents which are selected, independently of one another, from H, C 1 -C 8 -alkyl which may be substituted by OH, OC 1 -C 8 -alkyl or halogen, or phenyl, naphthyl, pyrrolyl, CN, NO 2 , CF 3 , CHF 2 , halogen, SO 2 R 4 or SR 4 where R 4 is H or C 1 -C 8 -alkyl, or where the substituents are selected, independently of one another, from C 1 -C 8 -alkyl, phenyl, CF 3 , CHF 2 , CN, NO 2 , halogen, OC 1 -C 8 -alkyl or SR 4 where R 4 is H or C 1 -C 8 -alkyl, and Y is H, C 1 -C 8 -alkyl, Hal or CF 3 .

Another preferred embodiment is the use of compounds of the formula I where Ar is pyrimidinyl which has one to three substituents which are selected, independently of one another, from H, C 1 -C 8 -alkyl, phenyl, naphthyl, C 3 -C 6 -cyclohexyl [sic], OH, OC 1 -C 8 -alkyl, halogen, CN, NO 2 , CF 3 , CHF 2 and a 5- or 6-membered heterocyclic aromatic or non-aromatic radical with 1 to 3 hetero atoms selected from O, N and S.

Another preferred embodiment is the use of compounds of the formula I where Ar is pyridinyl which has one to four substituents which are selected, independently of one another, from H, C 1 -C 8 -alkyl, phenyl, naphthyl, OH, OC 1 -C 8 -alkyl, halogen, CF 3 , CN, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl and a 5- or 6-membered heterocyclic aromatic radical with 1 to 3 hetero atoms selected from O, N and S.

The invention also embraces the acid addition salts of the compounds of the formula I with physiologically tolerated acids. Examples of suitable physiologically tolerated organic and inorganic acids are hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, oxalic acid, maleic acid, fumaric acid, lactic acid, tartaric acid, adipic acid or benzoic acid. Other acids which can be used are described in Fortschritte der Arzneimittelforschung, Volume 10, pages 224 et seq., Birkhauser Verlag, Basle and Stuttgart, 1966.

The compounds of the formulae [sic] I may have one or more centers of asymmetry. The invention therefore includes not only the racemates but also the relevant enantiomers and diastereomers. The invention also includes the tautomeric forms in each case.

The compounds of the formula I′ can be prepared by methods similar to conventional ones as described, for example, in A. R. Katritzky, C. W. Rees (ed.), “Comprehensive Heterocyclic Chemistry”, 1st Edition, Pergamon Press 1984, in particular Vol. 3, Part 2A; D. J. Brown “The Pyrimidines”, in “The Chemistry of Heterocyclic Compounds”, E. C. Taylor (ed.), John Wiley & Sons Inc. NY, in particular Vol. 16+Suppl. I+II (1985) and Vol 52 (1994) and literature cited therein. The process for preparing the compounds comprises

i) reacting a compound of the general formula II:

where Y 1 is a conventional leaving group, with a compound of the general formula III

H—B—Ar;

ii) to prepare a compound of the formula I′ where A is oxygen or sulfur or NR 4 :

reacting a compound of the general formula IV:

where Z 1 is O, S or NR , and A 1 is C 0 -C 18 -alkylene, with a compound of the general formula VI

Y 1 —A 2 —B—Ar

where Y 1 has the abovementioned meanings, and A 2 is C 1 -C 18 -alkylene, where A 1 and A 2 together have 1 to 18 carbon atoms,

iii) to prepare a compound of the formula I′ where A comprises the group COO or CONR 4 :

reacting a compound of the general formula VII:

or a salt thereof, where Y 2 is OH, OC 1 -C 4 -alkyl, Cl or, together with CO, is an activated ester group, and A 1 has the abovementioned meanings, with a compound of the formula VIII:

Z 1 —A 2 —B—Ar

where A 2 has the abovementioned meanings, and Z 1 is OH or NHR 4 ,

iv) to prepare a compound of the formula I′ where A comprises the group OCO or NR 4 CO:

reacting a compound of the formula IV

where Z 1 is C or NR 4 , with a compound of the formula X:

Y 2 CO—A 2 —B—Ar

where A 2 , B and Y 2 have the abovementioned meanings, is and where R 1 , R 2 , R 3 , A, B and Ar have the above-mentioned meanings.

The reactions described above generally take place in a solvent at from room temperature to the boiling point of the solvent used. Examples of solvents which can be used are ethyl acetate, tetrahydrofuran, dimethylformamide, dimethoxyethane, toluene, xylene or a ketone, such as acetone or methyl ethyl ketone.

An acid acceptor is present if required. Suitable acid acceptor s are inorganic bases such as sodium or potassium carbonate, sodium methoxide, sodium ethoxide, sodium hydride or organic bases such as triethylamine or pyridine. The latter can also serve as solvents.

The crude product is isolated in a conventional way, for example by filtration, removal of the solvent by distillation or extraction from the reaction mixture, etc. The resulting compound can be purified in a conventional way, for example by recrystallization from a solvent, chromatography or conversion into an acid addition compound.

The acid addition salts are prepared in a conventional way by mixing the free base with the appropriate acid, possibly in solution in an organic solvent, for example a lower alcohol such a methanol, ethanol or propanol, an ether such as methyl t-butyl ether, a ketone such as acetone or methyl ethyl ketone, or an ester such as ethyl acetate.

The abovementioned starting materials are disclosed in the literature or can be prepared by known processes.

To treat the abovementioned disorders, the compounds according to the invention are administered in a conventional manner orally or parenterally (subcutaneously, intravenously, intramuscularly, intraperitoneally). Administration can also take place with vapors or sprays through the nasopharyngeal space.

The dosage depends on the age, condition and weight of the patient and on the mode of administration. As a rule, the daily dose of active substance is about 10 to 1000 mg per patient and day on oral administration and about 1 to 500 mg per patient and day on parenteral administration.

The invention also relates to pharmaceutical compositions which contain the compounds according to the invention. These compositions are in the usual solid or liquid pharmaceutical administration forms, for example as tablets, film-coated tablets, capsules, powders, granules, sugar-coated tablets, suppositories, solutions or sprays. The active substances can in these cases be processed with conventional pharmaceutical aids such as tablet binders, fillers, preservatives, tablet disintegrants, flow regulators, plasticizers, wetting agents, dispersants, emulsifiers, solvents, release-slowing agents, antioxidants and/or propellant gases (cf. H. Sucker et al., Pharmazeutische Technologie, Thieme-Verlag, Stuttgart, 1978). The administration forms obtained in this way normally contain the active substance in an amount from 1 to 99% by weight.

The following examples serve to explain the invention without limiting it.