CS228548B2 - Method for the production of pentapeptide - Google Patents

Description

The invention relates to a process for the preparation of pentapeptides of the general formula I,

A — B — Gly — D — E (I).

in which

A is a radical of formula (II)

(II) where

Z ¹ is an amidino group,

R 1 is hydrogen or C 1 -C 4 alkyl;

R1 and R2 together form an ethylene bridge, and

R3 represents a hydroxy or alkoxy2 group having 1 to 4 carbon atoms attached to the 3, 4 or 5 position,

B represents the residue (Dj-isomer of the natural α-amino acid,

D is a radical of formula III,

Z ²

AND

R4 CH2

I - N - CH - CO - (III) in which

R 4 represents a hydrogen atom or a C 1 -C 4 alkyl group;

Z ² is phenyl, optionally mono- or di-substituted with halogen, nitro, C 1 -C 4 alkyl and / or C 1 -C 4 alkoxy, and

E represents a radical of formula IV

Rs R6

I - N - CH - CH 2 OH (IV) wherein

R 5 represents a hydrogen atom or a C 1 -C 4 alkyl group;

R 6 represents a hydrogen atom, a substituent corresponding to a residue attached to the α-carbon of a natural «-amino acid, a radical of the formula - (CH ₂ ) _{m -} CH ₂ OH where m is an integer of 1 to 6, or a radical of the formula

- (CH ₂ ) _n -CH ₂ -S (O) _p -R 7 wherein

R 7 is an alkyl group having 1 to 5 carbon atoms and, for example, independently of one another, is a number of 0, 1 or 2, provided that if n is lap 0, then R 7 is not a methyl group where residues A and D have (L) -configuration, residue E has the (Dj- or (Ly1) configuration and residue B has the (Dj-configuration) as well as their physiologically hydrolysable, physiologically acceptable esters and salts and complexes of these pentapeptides and esters.

In describing the polypeptides of the invention as pentapeptides, it should be understood that the amino alcohol moiety of E is considered to be an amino acid derivative.

The term "amidino" refers to a group of the formula

NH

NH ₂ —C—.

As mentioned above, the compounds produced by the process of the invention exhibit advantageous biological properties, in particular inhibitory activity on luteinizing hormone secretion, and can be used as pharmaceutically active substances.

The E moiety may have either (L 1 - or (D 1 -configuration). In the text of the present invention and in the definition of the present invention, the terms "(L) -? - aminoalcohol residue" and "(Dj- / 3-aminoalcohol residue)" refers to those residues in which the relative configuration corresponds to the configuration of the residues of the corresponding (L1-α-amino acid and (D) -a-amino acid respectively [wherein the carboxyl group in that (LJ- or (D) -amino acid residue) is replaced in each case It is to be understood that these radicals can carry an alkyl substituent of 1 to 4 carbon atoms on the nitrogen atom in the β-position.

In the pentapeptides of formula I, the following meanings of the individual symbols or combinations thereof are preferred:

1) The two symbols R, and R ₂ are hydrogen;

R 3 is hydroxy. Most preferably, R 3 occupies position 4 and is especially 4-hydroxy,

3] B is a residue (DJ-isomer of a natural non-aromatic α-amino acid. Most preferably B is a - (D) -Ala-,

R 4 represents a C 1 -C 4 alkyl group, for example a methyl group. When R4 is a (C 4-C alky) alkyl group, it is preferably n-propyl, isopropyl or n-butyl, especially n-propyl,

5] Z ² is preferably a phenyl group optionally mono- or disubstituted with one or two of fluoro, chloro and nitro, especially fluoro. When Z ² substituted phenyl group is preferably mono-substituted phenyl, in particular m- or p-substituted phenyl group. Most preferably, Z ² is phenyl or m- or p-fluorophenyl group, especially a phenyl or p-fluorophenyl,

6.1] R 5 preferably represents a hydrogen atom,

6.2 J As the substituent attached to the «-carbon of the natural--amino acid, R 6 preferably represents a group of the formula

CHs — s — ch ₂ —ch ₂ -,

HO-CH2-,

CH-CH (OH) - or H2 NC-CH ₂ -CH 2,

6.3) When R 6 has a meaning other than that described in 6.2), it preferably represents the remainder of the formula

CH 3 -SO-CH ₂ -CH ₂ - or

CHs — SO ₂ —CH ₂ —CH ₂ -,

6.4) Most preferably, R6 is a radical of the formula CH-SO-CH ₂ -CH ₂ - and

6.5) The radical E, including the preferred radicals E as defined in paragraphs 6.1) to 6.4 above, preferably has (L 1 -configuration (as defined above). Most preferably, E is -Met (O) -oil, i.e. the (L) -methioninol sulfoxide residue.

The hydroxyl groups in the pentapeptides of the formula I, in particular the hydroxyl group of the terminal residue, the 6-aminoalcohol as defined by the symbol E, can be esterified to give the corresponding physiologically hydrolyzable, physiologically acceptable esters, i.e. esters which give the physiologically acceptable acid.

Suitable esters include, for example, esters of mono and dicarboxylic acids, especially esters of carboxylic acids having 2 to 5 carbon atoms, such as acetates, and aromatic carboxylic acids, such as benzoates.

The pentapeptides of the formula I and their esters may be in the form of acid addition salts or in the form of complexes. Acid addition salts may be formed with, for example, organic acids, polymeric acids, and inorganic acids. Such acid addition salts include, for example, hydrochlorides and acetates. By "complexes" is meant compounds of a known type prepared from the pentapeptides of the general formula I and their esters by addition of inorganic compounds, for example inorganic salts or hydroxides such as salts of calcium, magnesium, aluminum, cobalt and especially zinc, or addition of polymeric organic substances.

One group of compounds of the invention are the pentapeptides of formula I wherein:

Z ¹ is an amidino group,

B is - (D) -Ala-,

Z ² is phenyl, optionally mono- or di-substituted with halogen, nitro, C 1 -C 4 alkyl or C 1 -C 4 alkoxy; and

R1, R2, R3, Ra and E are as defined in formula I, and their acid addition salts and complexes.

The present invention provides a process for the preparation of the compounds described above. These compounds can be prepared by reacting a pentapeptide or ester thereof having the sequence of formula I wherein Z ¹ is hydrogen, with a reagent capable of introducing the amine group Z ¹ to the terminal nitrogen of the above pentapeptide or ester. , and the thus obtained pentapeptide or ester thereof is isolated in free form or in the form of an acid addition salt or complex.

The above reaction can be carried out analogously to the procedure described below in the example. If the preparation of the starting materials is not specifically described, these compounds are either known or can be prepared and purified by methods known per se.

A suitable reagent for carrying out the reaction according to the invention is, for example, 1-amidino-3,5-dimethylpyrazole, conveniently used in the form of a salt, for example in the form of a nitrate. The reaction is conveniently carried out in a solvent or diluent inert under the reaction conditions, for example dimethylformamide.

The pentapeptides and esters of the invention, as well as their physiologically acceptable acid addition salts and complexes, exhibit valuable pharmacological properties as evidenced by animal testing. In particular, these compounds inhibit luteinisin hormone secretion and have central nervous system depressant activity, as exemplified by the following tests.

Inhibitory activity on luteinizing hormone secretion; inhibition of ovulation in rats

Adult female rats weighing 200-250 g, with a regular four-day ester cycle, are maintained under standard conditions (14 hours of light per day from -0.00 to 18.00 hours, 24 ° C and 55-60%). relative humidity), while not restricting food and water intake. The test compound is administered subcutaneously in the preest stage, with the test doses being administered once at 13.00 hours and then again at 16.00 hours. Twenty hours after the first dose, the rats are sacrificed, their fallopian tubes are removed, and the total number of eggs in both fallopian tubes is determined using a microscope. Evaluation is carried out by judging the inhibition of ovulation only if no egg can be detected. Each dose was tested in five rats.

2. Depressive activity on the central nervous system

This assay is performed by monitoring changes in the spontaneous behavior of mice and rats in accordance with the principles described by J. H. Nodid et al. in "Animal and Clinical Pharmacological Techniques in Drug Evaluation", Chicago, 1964, and in "Psychopharmacologia", 13, 222-257 (Berlin, 1968).

The pentapeptides, esters, salts and complexes described above can be used accordingly

(a) for the treatment of patients with disorders associated with or modulated by luteinizing hormone secretion, or whose etiology includes physiological regulation of luteinizing hormone secretion, for example in the treatment of prostate hypertrophy or in the treatment of menopausal syndrome, in particular post-menopausal hot flashes studies described by Tataryn et al. ("Thermo-regulatory mechanisms and their Therapeutic Implications", 4th International Symposium on the Pharmacology of Thermoregulation, Oxford, 1979; publ. Karger, Basel 1980, pp. 202-207) and Casper et al. ("Science", 205, p. 823-825 (1979)) and as psychopharmaceuticals, for example in the treatment of psychotic conditions.

For both these aj and bj uses, the recommended dose is in the range of 0.1 to 10 mg of pentapeptides or ester thereof, the total dose being administered in several divided doses two to four times daily in unit dosage form or in a prolonged form. Thus, suitable unit dosage forms, for example, for oral administration, contain from 0.025 to 5.0 mg of the pentapeptide or ester mentioned above, or an equivalent amount of a pharmaceutically acceptable salt or complex, together with a solid or liquid pharmaceutical diluent or carrier. These compositions may take the form of, for example, solutions or tablets.

The invention further describes

(1) a method of inhibiting luteinizing hormone secretion, in particular a method of treating prostate hypertrophy or menopausal syndrome, in particular post-menopausal hot flashes, and a method of treating psychotic disorders in patients in need of such treatment, comprising administering to said patient an effective amount of pentapeptides or a physiologically hydrolyzable, physiologically acceptable ester, or a physiologically acceptable acid addition salt or complex of such pentapeptides or ester, and

(2) the pentapeptides, esters, acid addition salts and complexes referred to in (1) above as pharmaceuticals, ie for use in the treatment of human or animal, in particular for use as described in (1) above; and

3) pharmaceutical compositions containing the pentapeptides, esters, acid addition salts or complexes mentioned in paragraph 1j above as active ingredients.

The following common abbreviations are used in the specification, in the examples, and in the definition of the invention:

Met-ol = residue of (L 1 -methioninol, of formula CH 5 SCH 2 CH 2 CH (CH 2 OH) NH -,

Met (O) -iol = residue (L 1 -methioninol sulfoxide of formula CH 3 -S (O) —CH 2 CH 2 CH (CH 2 OH) -NH ",

MeTyr = —N — methyl-Tyr-,

MeTyr (Butj = -N-methyl-O-tert-butyl-Tyr-, MePhe = -N-methyl-Phe-, (N-propyl-Phe - -Nn-propyl-Phe-, (N-isobutyl) Phe - -N- isobutyl-Phe-, (N-butyl) -Pe = -Nn-butyl-Phe-, (N-propyl-Phe- (pF) = -Nn-propyl-p-fluoro-Phe,

Boc = t-butoxycarbonyl,

Z - Benzyloxycarbonyl.

In accordance with the standard nomenclature, the L-configuration is considered for all three-letter amino acid residues unless otherwise indicated. Example 1

N '-amidino-Tyr- (D-Ala-Gly-MePhe-Met (O-ol-acetate) H-Tyr- (D) -Ala-Gly-MePhe-Met (O) -ol-hydrochloride, dissolved in 10 ml of dimethylformamide, treated with 1.9 g of 1-amidino-3,5-dimethylpyrazolonitrate in 0.5 ml of N-methylmorpholine and 0.8 ml of triethylamine. The residue is dissolved in water and applied to a chromatographic column containing 50 g of a weakly acidic ion exchanger. After washing the column with 0.1% acetic acid, the product is eluted with an increasing gradient of acetic acid. Fractions containing the title compound are combined and lyophilized to give the title compound as a pale amorphous powder decomposing at 140 degrees Celsius, with an optical rotation of [α] _η ²⁰ - = -50.8 ° (c = 0.7 in dimethylformamide i.

Example 2

The following compounds were prepared in an analogous manner to Example 1:

2.1 bH-amidino-Tyr- (D j -Ala-Gly-MePhe (β-Fj-Met (γ-ol hydrochloride), optical rotation [α] d ²⁰ = -29.3 ° (c = 1 in 95) % acetic acid),

2.2Bamidino-Tyr- (D) -Ala-Gly- (N-propyl) Phe-Met-ol hydrochloride, having an optical rotation of [α] _D ²⁰ = -41.0 ° (c = 1 in dimethylformamide j, decomposing) at 90 ° C and

2.3. N '-amidino-Tyr- (D' -Ala-Gly- (N-propyl) -Phe-Met (O-ol-hydrochloride, O 'optical rotation [α] _D ²⁰ = -33.8 ° (c = 1 in 95% acetic acid).

Claims (2)

SUBJECT A process for the preparation of pentapeptides of the general formula I, A — B — Gly — D — E (I) wherein where Z ¹ is an amidino group, R 1 represents a hydrogen atom or a C 1 -C 4 alkyl group and R 2 represents a hydrogen atom or R 1 and R 2 together form an ethylene bridge, and R3 represents a hydroxy or alkoxy group having 1 to 4 carbon atoms attached to the 3, 4 or 5 position, B represents the residue of the (D) -isomer of the natural α-amino acid, D is a radical of formula III, Z ² AND Rl CHz I - N - CH - CO - (HI) in which R a is hydrogen or C 1 -C 4 alkyl and Z ² is phenyl, optionally mono- or di-substituted with halogen, nitro, C 1 -C 4 alkyl and / or C 1 -C 4 alkoxy, E is a radical of formula (IV), Rs R6 I - N - CH - CH 2 OH OF THE INVENTION in which R 5 represents a hydrogen atom or a C 1 -C 4 alkyl group; R 6 represents a hydrogen atom, a substituent corresponding to the residue attached to the α-carbon of the natural α-amino acid, a residue of the formula - (CH ₂ ) _m - CH ₂ OH where m is a number of 1 to 6, or a residue of the formula - (CH 2) _n (O) _p -R 7 where R 7 is a C 1 -C 5 alkyl group and, for example, independently of one another, is a number of 0, 1 or 2, provided that if n is lap 0, then R 7 is not a methyl group, with radicals A and D having (L 1 -configuration, the remainder E has the (D) - or (L) -configuration and residue B has the (D) -configuration as well as their physiologically hydrolysable, physiologically acceptable esters and salts and complexes of these pentapeptides and esters, that the pentapeptide or ester thereof having the sequence of formula I wherein Z ¹ is a hydrogen atom is reacted with a reagent capable of introducing the amidino group Z ¹ to the terminal nitrogen of the aforementioned pentapeptide or ester, and the pentapeptide or its thus formed the ester is isolated in free form or in the form of an acid addition salt or complex. 2. A process according to claim 1, wherein the corresponding starting materials are used to form compounds of formula (I) in which: B is a residue of D-Ala and Z ¹ , R ¹ , R 2, R 1j, D and E are as defined in 1.