BE814419R - (1-Alpha-aminoisobutyryl) corticotrophins - having greater efficacy and prolonged activity than natural ones - Google Patents

Abstract

The octadecapeptide amides represented by the formulae Ibu' Lys17,18 -ACTH-(1-18)-NH2 Ibu' Nle4 -ACTH (1-18)-NH2 Ibu' Nle4 Lys17,18 -ACTH (1-18)-NH2 and their acid-addn. salts and complexes Ibu = alpha-aminoisobutyryl; Nle = norleucine, Lys = lysine. The improved props. are due to them being less sensitive to the hydrolytic activity of intracellular aminopeptidase, and the cpds. are useful for treating rheumatic disorders, allergic and adrenergic disorders in man and animals.

Description

       

   <EMI ID = 1.1>

  
The present invention relates to octadecapeptides acting as!

  
 <EMI ID = 2.1>

  
amino acid radical at the terminal amino radical instead of the serine radical of natural corticotropin and it also refers to their non-toxic acid addition salts and complexes.

  
More particularly, it relates to α-aminoisobutyryl-L-

  
 <EMI ID = 3.1>

  
L-arginyl-L-tryptophyl-glycyl-L-lysyl-L-prolyl-L-valyl-glycyl-L- <EMI ID = 4.1> nyl-L-arginyl-L-tryptophyl-glycyl-L-lysyl-L- prolyl-L-valyl-glycylL-lysyl-L-lysyl-L-arginyl-L-arginine. as amide, (symboly-

  
 <EMI ID = 5.1>

  
tyryl-L-tyrosyl-L-seryl-L-norleucyl-L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycyl-L-lysyl-L-prolyl-L-valyl-

  
 <EMI ID = 6.1>

  
to their non-toxic acid addition salts and to their complexes, as well as to their preparation.

  
The Applicant has already discovered that the substitution for ex.

  
 <EMI ID = 7.1>

  
in a peptide acting like corticotropin greatly improves the biological properties of this peptide, increases its efficiency and prolongs its action (see main patent). This improvement in properties is due to a lower sensitivity of the peptide to the action of intracellular aminopeptidase. The pursuit of

  
 <EMI ID = 8.1>

  
naturally occurring corticotropic hormone and known peptides, including a known octadecapeptide comprising an α-aminoisobutyryl group at the amino terminus in place of the dE group

  
 <EMI ID = 9.1>

  
mone corticotrope (also called ACTH) comprising in position 4 a residue of norleucine instead of the residue of methionine offers an advantage which results from the fact that peptides containing methionine are often oxidized to the corresponding sulfoxides which inactivate. Therefore, replacing methionine by norleucine avoids this drawback. It is also known that the synthesis or 900 9 9 * or .. peptides containing arginine is very difficult because of

  
 <EMI ID = 10.1>

  
only side reactions. In this connection, the replacement of arginine by lysine facilitates the synthesis of the desired peptides. The Applicant has confirmed that modifications to the positions

  
 <EMI ID = 11.1>

  
my natural corticotrope leads to excellent peptides having remarkable pharmacological activities.

  
According to the present invention, the octadecapeptides can be obtained by condensation of the amino acids one by one or by condensation of small peptides one by one in the usual manner.

  
The final condensation reaction giving the octadecapeptides is carried out for example by means of a protected decapeptide of formula:

  
 <EMI ID = 12.1>

  
glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycine,

  
 <EMI ID = 13.1>

  
has a radical protecting the carboxyl function, X represents an L-methionyl or L-norleucyl radical, which is condensed with

  
a protected octapeptide of the formula:

  
 <EMI ID = 14.1>

  
being inert at a temperature of -20 to +60 [deg.] C in about 2 hours to 7 days and by removing the protective radicals of the resulting octadecapeptide from the formula:

  
 <EMI ID = 15.1> <EMI ID = 16.1>

  
conventional at a temperature of about -20 to +60 [deg.] C in about 30 mi-

  
 <EMI ID = 17.1>

  
of formula:

  
a-aminoisobutyryl-L-tyrosyl-L-seryl-XL-glutamyl-Lhistidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycyl-L-lysylL-prolyl-L-valyl-glycyl-L-lysyl-L- lysyl-Y

  
where Y represents L-lysyl-L-lysine as an amide or L-arginyl-L-arginine as an amide and X has the meaning above, excluding however the octadecapeptide in

  
the formula in which X represents the L-methionyl radical and Y represents L-arginyl-L-arginine in the form of an amide.

  
The condensation between the decapeptide and the octapeptide can be carried out according to conventional methods. To the number

  
of these processes, it is appropriate to cite that with azide, that with dicyclohexylcarbodiimide, that with carbonyldiimidazole, that

  
mixed anhydride, that with the activated ester (for example with the

  
 <EMI ID = 18.1>

  
p-nitrophenylthiol, with pentachlorophenyl ester), that with isoxazolium, that with N-carboxyanhydride, that with tetraethyl pyrophosphite and that with ethyl chlorophosphite in addition to the combined processes and the processes in common use. can also be prepared according to the so-called solid phase peptide synthesis methods. Although the above methods lend themselves to the formation of any peptide bond in octadecapeptides

  
of the invention, the most commonly applied methods are

  
 <EMI ID = 19.1>

  
the mixed anhydride and that with the activated ester.

  
During the preparation of the desired octadecapeptides, any free functional radicals not participating in the reaction are advantageously protected, especially by means of radicals which can be easily removed by hydrogenolysis, <EMI ID = 20.1>

  
 <EMI ID = 21.1>

  
protected by esterification, for example by means of a lower alkanol (such as methanol, ethanol, propanol or t-butanol) or by means of an aralkanol (such as benzyl alcohol,

  
 <EMI ID = 22.1>

  
radicals protecting the carboxyl function are introduced according to the usual technique.

  
The amino radical is preferably protected by the introduction of a radical such as a t-butoxycarbonyl, t-amyloxycarbonyl, o-nitrophenylsulfenyl, 2- (p-diphenyl) isopropyloxycarbonyl, benzyloxycarbonyl, p-toluenesulfonyl, formyl or trityl radical of usual way. For the protection of the guanidyl radical of arginine, a nitro, p-toluenesulfonyl or adamantyloxycarbonyl radical is preferably chosen, but protection of the guanidyl radical is not always necessary. The E-amino radical of lysine is advantageously protected by radicals capable of protecting the amino function of the kind described above.

   The Y-carboxyl radical of glutamic acid is preferably protected by radicals capable of protecting the carboxyl function of the above type and the imidazole radical of histidine can be protected by a p-toluenesulfonyl, benzyloxycarbonyl or benzyl radical, etc. In addition, the hydroxyl radical of serine or tyrosine can be protected by an acetyl, benzyl or t-butyl radical, but this protection is not always necessary.

  
The inert solvent used for the condensation is dimethylformamide, dimethylsulfoxide, dioxane, hexamethylphosphortriamide or a mixture of such solvents, optionally aqueous.

  
 <EMI ID = 23.1> <EMI ID = 24.1>

  
respectively.

  
In these tables, the abbreviations are as follows:
Ibu = α-aminoisobutyric acid residue,

  
Tyr = residue of L-tyrosine,

  
Ser = L-serine residue,

  
Met = L-methionine residue,

  
 <EMI ID = 25.1>

  
Glu = residue of glutamic acid,

  
His = L-histidine residue,

  
Phe = residue of L-p henylalanine,

  
Arg = residue of L-arginine,

  
Trp = L-tryptophan residue,

  
Gly = glycine residue,

  
Lys = L-lysine residue,

  
Pro = L-proline residue,

  
Val = remainder of L-valine,

  
Boc = t-butyloxycarbonyl,

  
 <EMI ID = 26.1>

  
HOSu = N-hydroxysuccinimide,

  
OBz = benzyloxy,

  
HOBt = 1-hydroxybenzotriazole.

  

 <EMI ID = 27.1>
 

  

 <EMI ID = 28.1>
 

  

 <EMI ID = 29.1>
 

  
 <EMI ID = 30.1> ceutically acceptable, depending on the reaction conditions chosen. In addition, the salts can also be obtained by reaction of peptides with inorganic acids, such as aqueous hydrogen halides (hydrofluoric, hydrobromic or hydrochloric acid) or as such (hydrogen fluoride, hyorogen bromide or chloride of hydrogen). hydrogen), sulfuric acid or phosphoric acid, or with organic acids, such as acetic acid, formic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, methanesulfonic acid, propionic acid, glycolic acid, lactic acid, pyruvic acid, oxalic acid, malonic acid, benzenesulfonic acid or toluenesulfonic acid, in the usual manner.

   The acid can be taken in an equimolar amount or in excess for salt formation.

  
In addition, the octadecapeptides obtained according to the invention can be converted into corresponding complexes by reaction with a heavy metal capable of forming a complex, such as zinc, copper, iron, nickel or cobalt, or a polyamino acid capable of forming. a complex, such as polyglutamic acid, polyaspartic acid, copoly-glutamyltyrosine or copolyaspartylglutamic acid, optionally as a mixture. The complex can be prepared by reacting the octadecapeptide in accordance with the invention with a heavy metal compound such as a heavy metal halide, such as zinc chloride, copper chloride, iron chloride or chloride. cobalt, or a heavy metal hydroxide, such as zinc hydroxide, in a weight ratio of about 1: 0.1 in a weakly acidic medium and preferably at a pH of 6.5 to 7.0, as usual.

   Among the heavy metals, zinc is especially preferred. A complex with a polyamino acid can

  
be prepared by reaction of octadecapeptide in accordance with the invention <EMI ID = 31.1>

  
 <EMI ID = 32.1>

  
 <EMI ID = 33.1>

  
 <EMI ID = 34.1>

  
100,000 and in particular 2,000 to 6,000. It is preferable to use the polyamino acid which has been neutralized beforehand with an alkali, such as sodium hydroxide. Others

  
 <EMI ID = 35.1>

  
benzyl alcohol, phenol or thimerosal, buffers, for example with citrate, phosphate or carbonate, or agents making the medium isotonic, for example sodium chloride, can be added during the preparation of the complexes.

  
The table below makes it possible to compare the results of the tests of the ability to stimulate the adrenal glands for the octadecapeptides of the invention, for the natural corticotropic hormone, for the hormone sold under the name Cortrosyn (Company

  
 <EMI ID = 36.1>

  
main).

  
 <EMI ID = 37.1>

  

 <EMI ID = 38.1>


  
Note: The results are expressed relative to the corticosteroid hormone

  
natural trope (ACTH). The activities are determined as described in the main patent.

  
As the table clearly shows, the octadecapeptides of the invention have excellent ability to stimulate the adrenal glands.

  
The octadecapeptides of the invention are highly useful and advantageous for therapeutic purposes, for example for the treatment of rheumatic fever or chronic, and for allergic or adrenergic conditions in humans and domestic animals, as well as for the disease. test of adrenal gland function in humans and animals.

  
Octadecapeptides, acid addition salts

  
and their complexes can be administered orally or parenterally in conventional forms, for example by injection, in the form of liquids, suspensions, emulsions or aerosols, optionally in combination with vehicles, stabilizers, emulsifiers, agents of conservation, buffers, isotonic agents and wetting agents suitable, under conditions providing a therapeutically effective amount of the active agent.

  
A subject of the invention is therefore also a pharmaceutical or veterinary composition which comprises a compound in accordance with the invention and an inert pharmaceutical excipient.

  
The effective dose can be easily determined by the physician from the directions given here. For example, a typical value for the doses of the octadecapeptides of the invention

  
is about 0.2 to 0.8 units / kg for the normal adult. The octadecapeptides are advantageously administered by injection in dosage form and the administration is repeated as needed.

  
on doctor's advice.

  
The invention is illustrated without being limited by the following examples.

EXAMPLE A -

  
Preparation of a-aminoisobutyryl-L-tyrosyl-L-serylL-methionyl-L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-Ltryptophyl-glycyl-L-lysyl-L-prolyl-L-valyl-glycyl -L-lysyl-L-

  
 <EMI ID = 39.1>

  
in the form of amide (I):

  
10 ml of concentrated ammonia are added to a solution j

  
 <EMI ID = 40.1>

  
 <EMI ID = 41.1>

  
After evaporation, the crystalline residue is extracted with ethyl acetate. The extract is washed with cold 0.5N hydrochloric acid

  
 <EMI ID = 42.1>

  
dried over anhydrous sodium sulfate and concentrated to dryness in vacuo. The residue is crystallized from acetate

  
 <EMI ID = 43.1> <EMI ID = 44.1>

  
Analysis for C19H29N305

  

 <EMI ID = 45.1>


  
 <EMI ID = 46.1>

  
 <EMI ID = 47.1>

  
methanol on catalytic palladium black for 150 minutes. The catalyst is separated by filtration and washed with methanol. The mixture of filtrate and wash liquor is evaporated in vacuo to give an oily residue which is solidified with petroleum ether. The solid is collected by filtration

  
 <EMI ID = 48.1>

  

 <EMI ID = 49.1>


  
 <EMI ID = 50.1>

  
in 20 ml of chloroform to a solution of 2.45 g of compound II in 30 ml of ethyl acetate. The mixture is stirred at room temperature.

  
 <EMI ID = 51.1>

  
and stirring is continued for 3 hours. The reaction mixture is concentrated in vacuo to obtain a residue which is placed

  
suspended in ethyl acetate. The suspension is washed successively with cold 0.5N hydrochloric acid, water, 1X sodium bicarbonate solution and water. By filtration, the fraction insoluble in ethyl acetate is collected,

  
washed and dried in vacuo. By recrystallization in <EMI ID = 52.1>

  

 <EMI ID = 53.1>


  
 <EMI ID = 54.1>

  
thanol on catalytic palladium black for 150 minutes. The catalyst is filtered off and the filtrate is concentrated in vacuo to obtain a crystalline residue. The residue is recrystallized from ethyl acetate and n-hexane to obtain in quantum

  
 <EMI ID = 55.1>

  

 <EMI ID = 56.1>


  
 <EMI ID = 57.1>

  
amide form (V)

  
2.84 g of Nabenzyloxycarbonyl-NE-t-butyloxycarbonyl-L-lysine N-hydroxysuccinimide ester is added to a solution of

  
 <EMI ID = 58.1>

  
mixing at room temperature for 68 hours. After evaporation, the residue is dissolved in ethyl acetate and the mixture is washed.

  
 <EMI ID = 59.1>

  
whereby the solution is evaporated to obtain a residue. This residue is dissolved in ethyl acetate and the solution is stored in a refrigerated cabinet. The gelatinous precipitate is collected and

  
 <EMI ID = 60.1> <EMI ID = 61.1>

  

 <EMI ID = 62.1>


  
 <EMI ID = 63.1>

  
methanol on catalytic palladium black for 2 hours.

  
After separation of the catalyst, the filtrate is concentrated in vacuo. The residue is dissolved in ethyl acetate and precipitated from its solution by addition of petroleum ether. The precipitate is collected, washed and dried under vacuum to

  
 <EMI ID = 64.1>

  

 <EMI ID = 65.1>


  
 <EMI ID = 66.1>

  
of compound VI in a mixture of 30 ml of chloroform and 3 ml of methanol constituting the solvent. The mixture is stored for 3 hours at room temperature, then evaporated in vacuo. The residue is taken up in ethyl acetate and washed.

  
 <EMI ID = 67.1>

  
Extracted under vacuum to obtain a solid. The solid was precipitated from methanol and ether and the precipitate was collected by filtration, then washed and dried to obtain <EMI ID = 68.1>

  

 <EMI ID = 69.1>


  
 <EMI ID = 70.1>

  
sine as amide (VIII)

  
2.13 g of compound VII are hydrogenolized in 30 ml of methanol over 4 hours and 30 minutes over catalytic palladium black. After separation of the catalyst by filtration, the filtrate is evaporated in vacuo to obtain a residue. The residue is reprecipitated from methanol and ethyl acetate to obtain a gelatinous precipitate which is collected by filtration, which is washed.

  
 <EMI ID = 71.1>

  

 <EMI ID = 72.1>


  
 <EMI ID = 73.1>

  
bonvl-L-lysine as amide (IX)

  
309 mg of dicyclohexylcarbodiimide is added to a so-

  
 <EMI ID = 74.1>

  
L-lysyl-L-prolyl-L-valyl-glycine obtained as described in Bull. Chem. Soc. Japan 32., 1.471 (1964) and 173 ml of N-hydroxysuccinimide in 10 ml of ethyl acetate. We stir the mixture

  
 <EMI ID = 75.1>

  
res. To this mixture is added a cold solution of 1,395 g of compound VIII in 15 ml of dimethylformamide and the resulting solution is stirred for 64 hours at room temperature. After removing the dicyclohetylurea which separated, the filtrate is evaporated to dryness in vacuo to give a solid residue.

  
By adding methanol and water, a precipitate is formed which is collected, washed with water and dried under vacuum to obtain.

  
 <EMI ID = 76.1>

  

 <EMI ID = 77.1>


  
 <EMI ID = 78.1>

  
nyl-L-seryl-L-methionine in 13 ml of ethyl acetate and, under cooling in ice, 16 ml are added to this solution

  
 <EMI ID = 79.1>

  
The mixture was stored at room temperature for 1 hour, then evaporated in vacuo to obtain a residue. The residue is dissolved in 37 ml of dichloromethane and the solution is stirred.

  
 <EMI ID = 80.1>

  
under cooling. The organic layer is dried over sodium sulfate and evaporated in vacuo to obtain a crystalline residue. 25 ml of ether are added to the residue and collected.

  
the product by filtration and then dried under vacuum to obtain

  
 <EMI ID = 81.1>

  
10.65 g of t-butyloxycarbonyl-a- hydrazide are dissolved.

  
 <EMI ID = 82.1>

  
room temperature and the solution is cooled. We add

  
to this solution 14 ml of 2M sodium nitrite and the mixture is stirred for 5 minutes. The reaction mixture is extracted with 2 fractions of 70 ml of ether, the organic phase is dried over <EMI ID = 83.1>

  
The azide is dissolved in 58 ml of cold acetonitrile and the solution is stirred in an ice bath. 6.15 g of the methyl ester of L-seryl-L-methionine obtained as above are added to the solution.

  
 <EMI ID = 84.1>

  
evaporation under vacuum, an oily residue is obtained which

  
 <EMI ID = 85.1>

  
vement with cold IN hydrochloric acid, 5% sodium bicarbonate solution and saturated sodium chloride solution. The organic phase is dried over sodium sulfate

  
and evaporated in vacuo to obtain an amount of 13 g of t-butyloxycarbonyl-α-aminoisobutyryl-L-tyrosyl-Lseryl-L-methionine methyl ester, in the form of an oily residue.

  
The tetrapeptide ester obtained above is dissolved

  
 <EMI ID = 86.1>

  
to the solution. The mixture is heated under reflux for 2 hours,

  
 <EMI ID = 87.1>

  
of ethyl acetate to the resulting oily residue which is then kept in the fridge for 90 minutes. By adding 100 ml of ether and 100 ml of ethyl acetate, a gel is formed which is kept cool for 90 minutes so as to obtain

  
 <EMI ID = 88.1>

  

 <EMI ID = 89.1>


  
11. t-Butyloxycarbonyl-a-aminoisobutyryl-L-tyrosyl-

  
 <EMI ID = 90.1>

  
1.67 g of compound X is dissolved in 17 ml of dimethylformamide at room temperature and the solution is cooled <EMI ID = 91.1>

  
 <EMI ID = 92.1>

  
of 1M sodium, then the mixture is stirred for 5 minutes under ice cooling. The reaction mixture is extracted with
60 ml of ethyl acetate and the organic extract is washed with cold sodium bicarbonate solution and water, after which it is dried over anhydrous sodium sulfate.

  
On the other hand, 1.933 g of benzyloxycarbonyl-1-Yt-butyl-L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycine (38 ml of 50% acetic acid) are dissolved ( prepared as indicated

  
 <EMI ID = 93.1>

  
for 3 hours at room temperature over catalytic palladium black. After separating the catalyst by filtration, the filtrate was concentrated in vacuo at a bath temperature of 30 to 50 [deg.] C. The resulting oily residue was dissolved in 20 ml of acetic acid and the solution was lyophilized to obtain a quantity 2.62 g of

  
 <EMI ID = 94.1>

  
tryptophyl-glycine in the form of a light powder. The product is dissolved in 40 ml of dimethylformamide and 0.78 ml of triethylamine is added to the solution. The solution was cooled with ice and mixed with a solution of the azide of the tetrapeptide obtained above in ethyl acetate. The mixture is stirred for 22 hours and 30 minutes while cooling in ice. The resulting solid is collected by filtration and dissolved in

  
 <EMI ID = 95.1>
 <EMI ID = 96.1>
  <EMI ID = 97.1>

  
N -t-butyloxycarbonyl-L-lysine as amide (XII)

  
200 mg of compound IX is hydrogenolized in 20 ml of methanol over catalytic palladium black for 5 hours, then the catalyst is filtered off. The filtrate is concentrated in vacuo to about 3 ml. 6 ml of benzene and 30 ml of petroleum ether were added to the residual solution and the precipitate thus formed was collected, then washed and dried in vacuo to obtain 181 mg of N [pound] -t-butyloxycarbonyl-. L-lysyl-L-

  
 <EMI ID = 98.1>

  
oxycarbonyl-L-lysine in the form of an amide which is found to be homogeneous on thin layer chromatography (silica gel, n-butanol: acetic acid: water = 4: 1: 2 by volume).

  
Has a solution of 200 mg of compound XI in 5 ml of

  
 <EMI ID = 99.1>

  
! cooling the mixture in ice. The mixture is immediately added dropwise to an ice-cold mixture of 50 ml of acetate- &#65533;

  
 <EMI ID = 100.1>

  
washed and dried under vacuum to obtain 234 mg of benzyloxycarbonyl-a-aminoisobutyryl-L-tyrosyl-L-seryl-L-methionyl-Yt-butyl-L-glutamyl-L-histidyl-L-phenylalanyl hydrochloride. -L-

  
 <EMI ID = 101.1>

  
234 mg of the pro-decapeptide hydrochloride is dissolved.

  
 <EMI ID = 102.1>

  
32 mg of N-hydroxysuccinimide and 0.021 ml of triethylamine in 4 ml of dimethylformamide at 0 [deg.] C. To this solution is added a cold solution of 107 mg of dicyclohexylcarbodiimide and the mixture is stirred at room temperature for 20 hours. The precipitate formed is collected by filtration by adding

  
15 ml of ethyl acetate, then washed and dried in vacuo to obtain a residue. The residue is lyophilized from acetic acid to give 351 mg of the desired compound in the form of a light powder.

  
13. a-Aminoisobutyryl-L-tyrosyl-L-seryl-L-methionyl-

  
 <EMI ID = 103.1>

  
351 mg of compound XII, 0.2 ml of ethanedithiol and 0.35 ml of anisole are dissolved in 4 ml of 90% aqueous trifluoroacetic acid and the solution is stored for 1 hour at

  
 <EMI ID = 104.1>

  
reaction, then the resulting precipitate was collected by filtration, washed and dried in vacuo. Then we dissolve the

  
 <EMI ID = 105.1>

  
solution on a 0.9 cm x 30 cm column of Amberlite CG-400 resin in acetate form. The column is eluted with acid

  
 <EMI ID = 106.1>

  
stained in the Folin-Lowry test. The eluates are concentrated to a small volume and lyophilized to obtain 267 mg of a powder. The powder is introduced into a 2.2 cm x 30 cm column of carboxymethylcellulose (Watman CM-52) and the column is eluted at the flow rate of 60 ml per hour with an ammonium acetate buffer.
(pH 6.50) exhibiting a linear concentration gradient of

  
 <EMI ID = 107.1>

  
n [deg.] 235 to 290, 10 ml / tube, then the mixture is concentrated and freeze-dried to obtain 153 mg of a powder. The powder was dissolved in a 12: 3: 4: 6 mixture of n-butanol, acetic acid, pyridine and water and the solution was subjected to partition chromatography on a Sephadex G-25 column. This 2.7 cm x 80 cm column is eluted at a flow rate of 70 ml per hour using the same solvent as above. We combine the fractions of

  
 <EMI ID = 108.1>

  
freeze-dried. The powder thus obtained is subjected to chromatography on a carboxymethylcellulose column as above, then lyophilization is carried out to obtain under

  
 <EMI ID = 109.1> 1,2, arginine 1.0, serine 0.9, glutamic acid 1.1, proline 1.0, glycine 2.0, α-aminoisobutyric acid 0.9, valine 1.0, methionine 1.0, tyrosine 1.0, phenylalanine 1.0. The ratio of trypto-

  
 <EMI ID = 110.1>

  
in the ultraviolet on a solution in sodium hydroxide N / 10. The product gives a unique stain with ninhydrin

  
and the Ehrlich, Pauly and Sakaguchi reagents by thin layer chromatography (cellulose plate, n-butanol: acetic acid-py-

  
 <EMI ID = 111.1>

  
4: 1: 2 by volume).

EXAMPLE B -

  
Preparation of α-aminoisobutyryl-L-tyrosyl-L-seryl-Lnorleucyl-L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycyl-L-lysyl-L-prolyl-L- valyl-glycyl-L-lysyl-L-lysyl-L-

  
 <EMI ID = 112.1>

  
2.50 g of p-methoxybenzyloxycar- hydrazide are dissolved.

  
 <EMI ID = 113.1>

  
4.2 ml of ice-cold 2M sodium nitrite are added to this solution.

  
 <EMI ID = 114.1>

  
20 ml of ice-cold ethyl acetate and 12 ml of carbohydrate are added.

  
 <EMI ID = 115.1> <EMI ID = 116.1>

  
extract again with ice-cold ethyl acetate. We combine

  
the organic extracts, dried over magnesium sulfate and added to a solution of 3.35 g of L-phenylalanyl-L-nitroarginyl-L-tryptophyl-glycine methyl ester formate

  
 <EMI ID = 117.1>

  
The mixture is concentrated by evaporation of ethyl acetate at a bath temperature below 20 [deg.] C. We keep the solution

  
 <EMI ID = 118.1>

  
of the solvent in vacuo, the syrupy residue was triturated in ethyl acetate and 5.46 g of a precipitate which separated was collected by filtration. By reprecipitation from aqueous methanol then repeated treatments using hot methanol, the desired compound is obtained in an amount of 2.53 g (53%).

  
 <EMI ID = 119.1>

  
calculated C, 55.51; H, 5.82; N, 17.66%

  
found C, 55.65; H, 5.76; N, 17.62%

  
 <EMI ID = 120.1>

  
A solution of 6.60 g of compound I in 7 ml of dimethylformamide and 63 ml of methanol is cooled in an ice bath.

  
 <EMI ID = 121.1>

  
stir the mixture for 40 minutes at room temperature. The mixture is cooled in an ice bath and neutralized with

  
 <EMI ID = 122.1>

  
of water, the precipitate which separated out is collected by filtration and washed with water. The resulting product is suspended

  
 <EMI ID = 123.1>

  
and the suspension is heated to boiling for a few minutes to induce crystallization, after which the whole is allowed to stand at room temperature overnight. The crystalline precipitate is collected by filtration, which is washed with methanol and with ether and then dried under vacuum to obtain

  
 <EMI ID = 124.1>

  

 <EMI ID = 125.1>


  
 <EMI ID = 126.1>

  
glycine (III)

  
65 ml of trifluoroacetic acid are added to a mixture of 6.50 g of compound II and 6.5 ml of 2-mercaptoethanol at 0 [deg.] C

  
 <EMI ID = 127.1>

  
The precipitate is collected by filtration and separated by the addition of ether, then washed with ether and dried in vacuo. The salt formed by the trifluoroacetic acid and the desired pentapeptide is dissolved in 75 ml of water, then the solution is passed through a 2.7 cm x 30 cm column of Amberlite CG-400 resin (in acetate form) in adding water supplements. The aqueous solutions are combined, concentrated under

  
 <EMI ID = 128.1>

  

 <EMI ID = 129.1>


  
 <EMI ID = 130.1>

  
compound III in 5 ml of dimethylformamide and the m-

  
 <EMI ID = 131.1> <EMI ID = 132.1>

  
 <EMI ID = 133.1>

  
sout the resulting crude product in 10 ml of methanol and add a little water (about 10 ml). The resulting precipitate was collected by filtration and the filtrate was concentrated in vacuo to obtain a gelatinous mass. About 10 ml of acetic acid is added.

  
 <EMI ID = 134.1>

  
washed thoroughly with 0.5M acetic acid and dried under vacuum over sodium hydroxide pellets and

  
 <EMI ID = 135.1>

  
 <EMI ID = 136.1>

  

 <EMI ID = 137.1>


  
 <EMI ID = 138.1>

  
0.70 g of compound IV is hydrogenolized for 8 hours in acetic acid over palladium. After separation of the catalyst by filtration, the filtrate is evaporated in vacuo to obtain a syrupy residue which is lyophilized in water and dried over sodium hydroxide pellets and over phosphorus pentoxide to obtain an amount of 0.60 g the desired compound

  
 <EMI ID = 139.1>

  

 <EMI ID = 140.1>


  
 <EMI ID = 141.1> <EMI ID = 142.1>

  
which separated and the filtrate is evaporated under vacuum to obtain a crystalline residue which is recrystallized from ethanol in order

  
 <EMI ID = 143.1>

  

 <EMI ID = 144.1>


  
 <EMI ID = 145.1>

  
of compound III and 0.42 ml of triethylamine in 8 ml of di-

  
 <EMI ID = 146.1>

  
The mixture is then added dropwise to 80 ml of ethyl acetate and the resulting precipitate is collected by filtration, washing with ethyl acetate and ether, then drying in vacuo to obtain a quantity of 1.77 g. A suspension of the crude product in methanol is heated to the boil for a few minutes, then the suspension is left to stand overnight. The precipitate is filtered off and washed.

  
with cold methanol and ether, then dried under vacuum over sodium hydroxide pellets and phosphorus pentoxide at 60 [deg.] C so as to obtain 1.84 g (87%) of compound sought.

  
 <EMI ID = 147.1>
 <EMI ID = 148.1>
  <EMI ID = 149.1>

  
 <EMI ID = 150.1>

  
Then added dropwise to 250 ml of ethyl acetate, then the resulting precipitate is separated by filtration, washed with ethyl acetate and with ether, then dried under vacuum to isolate an amount of 5.52 g. The resulting crude product is reprecipitated from acetic acid and methanol to

  
 <EMI ID = 151.1>

  

 <EMI ID = 152.1>


  
 <EMI ID = 153.1>

  
4.90 g of compound VIII are suitably mixed with 4.9 ml of 2-mercaptoethanol and the whole is cooled in an ice bath. 50 ml of trifluoroacetic acid are added thereto and the mixture is maintained

  
 <EMI ID = 154.1>

  
sometimes. The precipitate which separates on the addition of ether is collected by filtration, washed with ether and dried.

  
 <EMI ID = 155.1>

  

 <EMI ID = 156.1>


  
 <EMI ID = 157.1> <EMI ID = 158.1>

  
Benzyloxycarbonyl-a-aminoisobutyryl-L-tyrosine drazide in

  
15 ml of 1M hydrochloric acid. To this solution was added 3.0 ml of ice-cold 2M sodium nitrite dropwise and the mixture was stirred for 4 minutes. The azide which separates is extracted into ice-cold ethyl acetate. The organic extract is washed with ice-cold 1 M sodium bicarbonate and then dried over sulfate.

  
 <EMI ID = 159.1>

  
 <EMI ID = 160.1>

  
methionine in 5 ml of dimethylf &#65533; rmamide. The mixture is maintained at 40C for 65 hours, then washed with acid

  
 <EMI ID = 161.1>

  
dries over magnesium sulfate. By evaporation of the solvent in vacuo, a foamy residue is obtained which is recipitated several times from ethyl acetate to obtain 2.81 g of the tetrapeptide ester in the form of an amorphous solid. We dissolve

  
this solid in 25 ml of ethanol and 2.4 ml of hydrazine hydrate is added to the solution. After standing for 17 hours at room temperature, most of the solvent is removed by evaporation in vacuo. The residue is dissolved in a mixture of

  
10 ml of water and 20 ml of ethyl acetate, then the organic phase is washed with additional water. By concentrating this solution under vacuum, the hydrazide is obtained in the form of a gelatinous precipitate, which is purified by reprecipitation from ethanol and ethyl acetate to collect it in an amount of 1.86 g.

  
 <EMI ID = 162.1>

  

 <EMI ID = 163.1>


  
 <EMI ID = 164.1>

  
norleucine (XI) 10 ml of dichloromethane and 2 ml of carbonate are added

  
 <EMI ID = 165.1>

  
of L-norleucine methyl ester in 2 ml of water and stirred

  
The mixture. The organic phase is dried over magnesium sulfate and evaporated at a bath temperature of 25 [deg.] C. The residue is dissolved in dichloromethane and 1.20 g of benzyloxycarbonyl-L-serine and 1.03 g of dicyclohexylcarbodiinide are added with a little dichloromethane. The reaction mixture is maintained

  
 <EMI ID = 166.1>

  
the dicyclohexylurea which separated. The filtrate is evaporated in vacuo to obtain a residue. The residue is dissolved in ethyl acetate and the solution washed with hydrochloric acid.

  
 <EMI ID = 167.1>

  
sodium sulfate and evaporated in vacuo. By reprecipitation from ethyl acetate and petroleum ether, the desired pure dipeptide is obtained in an amount of 1.56 g (85%).

  
 <EMI ID = 168.1>

  

 <EMI ID = 169.1>


  
 <EMI ID = 170.1>

  
1.10 g of compound XI are hydrogenolized in a mixture

  
of 15 ml of methanol and 5 ml of acetic acid for 90 minutes on palladium. After separating the catalyst, the solvent is evaporated in vacuo to obtain a residue which is treated with

  
 <EMI ID = 171.1>

  
te of L-seryl-L-norleucine methyl ester. 0.73 g of the dipeptide ester and 0.35 ml of triethylamine are dissolved in 5 ml of dimethylformamide and this solution is mixed with a solution of benzyloxycarbonyl-a-aminoisobutyryl-L-tyrosine azide (obtained from

  
 <EMI ID = 172.1> drazide) in ethyl acetate. We let the reaction progress

  
 <EMI ID = 173.1>

  
 <EMI ID = 174.1>

  
then it is dried over magnesium sulfate and evaporated in vacuo to obtain a syrupy residue. The tetra ester is dissolved

  
 <EMI ID = 175.1>

  
te hydrazine to solution. After standing for 2 days at room temperature, the solvent is removed by evaporation in vacuo. The residue is dissolved in ethyl acetate and the solution washed with water, then dried thoroughly over magnesium sulfate. The gelatinous precipitate which separated was collected by filtration, washed with ethyl acetate and ether and dried in vacuo to give 0.93 g of product. By recrystallization from ethanol, the hydrazide is obtained in an amount of 0.73 g (47%)

  
 <EMI ID = 176.1>

  

 <EMI ID = 177.1>


  
 <EMI ID = 178.1>

  
0.46 g of compound XII is dissolved in 1.9 ml of acid

  
 <EMI ID = 179.1>

  
The solution is cooled in an ice bath and 0.42 ml of ice-cold 2M sodium nitrite is added dropwise. The mixture is stirred for 4 minutes and extracted with ice-cold ethyl acetate. The organic extract is washed with ice-cold 1M sodium bicarbonate, dried over magnesium sulfate and evaporated in vacuo at a bath temperature of 10 [deg.] C. The resulting tetrapeptide azide is mixed with an ice-cold solution of 0.62 g of compound IX and 0.21 ml of triethylamine in dimethylformamide. On con <EMI ID = 180.1>

  
dropwise to dO ml of ethyl acetate. The resulting precipitate is filtered off, washed with ethyl acetate and ether and lyophilized from acetic acid to give

  
 <EMI ID = 181.1>

  

 <EMI ID = 182.1>


  
 <EMI ID = 183.1>

  
in the form of an amide (obtained as described in Bull.Chem.Soc.Japa

  
 <EMI ID = 184.1>

  
tion, the filtrate is evaporated in vacuo. The residue is dissolved in 5 ml of water and 0.17 ml of triethylamine is added. The resulting solution is cooled in ice and, after addition

  
 <EMI ID = 185.1>

  
to obtain the desired hydrochloride. The product is dried under vacuum over sodium hydroxide pellets and phosphorus pentoxide at 60 [deg.] C for 2 hours to obtain it in quantity.

  
 <EMI ID = 186.1>

  
83 mg of N, N'-dicyclohexylcarbodiimide are added at an <EMI ID = 187.1>

  
overnight at room temperature. We add a

  
 <EMI ID = 188.1>

  
in 2 ml of dimethylformamide. The reaction mixture is kept

  
 <EMI ID = 189.1>

  
by volume of ethyl acetate and ether. The resulting precipitate was collected by filtration, washed with ethyl acetate and ether, then dried in vacuo to afford 242 mg of the crude protected octadecapeptide.

  
412 mg of the crude protected peptide is dissolved in 20 ml.

  
of liquid hydrogen fluoride by adding 100 mg of methionine

  
 <EMI ID = 190.1>

  
in 15 ml of ice water and, after washing the solution with ethyl acetate, the solution is passed through a column

  
1.7 cm x 20 cm of Amberlite CG-400 resin in acetate form. The column is washed with water and the aqueous eluates are collected which are evaporated in vacuo at a bath temperature of 50-60 [deg.] C. By lyophilization of the residue, 507 mg of the crude octadecapeptide freed from blocking radicals are obtained.

  
507 mg of the above crude peptide is dissolved in 10 ml of water and the solution is chromatographed on a 1.7 cm x 40 cm column of carboxymethyl cellulose (11.2 g on a dry basis of the product sold under the name of Serva, 0.63 meq / g) using ammonium acetate buffer (2,000 ml, pH 6.0) with a linear concentration gradient ranging from 0 to 0.6. mole / l. 10 ml fractions are collected, the appearance of the main peak is observed by spectrophoto: metry at 280 nm and the fractions containing the desired compound are pooled, after which they are evaporated at a bath temperature of 50 to 60 [deg.] C. The residue is lyophilized and dried in vacuo over sodium hydroxide pellets and <EMI ID = 191.1>

  
The 221 mg of partially purified octadecapeptide were subjected to partition chromatography on a column of

  
2.3 cm x 46 cm of Sephadex G-25 (medium quality, dry weight 50 g) using as solvent a 12: 3: 4: 6 mixture by volume of 1-butanol, acetic acid, pyridine and d 'water. 6 ml fractions are collected in which the peptide content is observed according to the Folin-Ciocalteu technique. The contents of tubes 12 to 15 and 16 to 40 are collected separately, evaporated

  
 <EMI ID = 192.1>

  
and lyophilizing the residues to obtain 43 mg of the F-1 fraction and 91 mg of the F-2 fraction respectively. The F-1 fraction is chromatographed again on the same Sephadex column exactly as above and the contents of the tubes are pooled.
16 to 3C to obtain 13 mg of fraction F-1-2. Fractions F-2 and F-l-2 are mixed and the whole is chromatographed again exactly as above. We collect the contents of the tubes

  
16 to 40, the mixture is evaporated in vacuo and lyophilized to obtain 89 mg of peptide.

  
The resulting 89 mg of peptides are finally subjected to chromatography on a column of 1.7 cm x 35 cm of carboxymethylcellulose (CM-52 from the company Merck) using

  
an ammonium acetate buffer (1,200 ml, pH 6.0) with a linear concentration gradient ranging from 0.1 to 0.6 mol / l. 8 ml fractions are collected and those (tubes 139 to 160) corresponding to the main peak are pooled and then evaporated, the residue is lyophilized and the product is dried under vacuum over sodium hydroxide pellets and over sodium pentoxide. phosphorus to obtain the desired pure octadecapeptide in a quantity of 62 g,

  
 <EMI ID = 193.1>

  
product gives a single stain on thin layer chromatography (F cellulose, Merck) in the presence of the solvent system <EMI ID = 194.1>

  
L-lysyl) -Ne-t-butyloxycarbonyl-L-lysine as an amide. By evaporation of the solvent under reduced pressure, a residue is obtained which is dried over sodium hydroxide pellets and over

  
 <EMI ID = 195.1>

  
tapeptide free of Na radical in 2 ml of dimethyl formamide

  
 <EMI ID = 196.1>

  
and 54 mg of 1-hydroxybenzotriazole. The mixture is cooled in an ice bath and 82.5 mg of dicyclohexylcarbodiimide are added thereto.

  
 <EMI ID = 197.1>

  
for 3 days, then poured into 100 ml of a 1: 1 mixture of ethyl acetate and ether. The resulting precipitate was collected by filtration, washed with ethyl acetate and ether and then dried in vacuo to afford 259 mg of the crude protected octadecapeptide.

  
413 mg of the crude protected peptide is dissolved in about 20 ml of liquid hydrogen fluoride by adding 100 mg

  
 <EMI ID = 198.1>

  
75 minutes at 0 [deg.] C, then evaporated under vacuum at 0 [deg.] C. The residue was dissolved in 15 ml of ice water and, after washing the solution with ethyl acetate, passed through a 1.7 cm x 20 cm column of Amberlite CG-400 resin (as acetate) using water for elution. The aqueous solutions are combined and evaporated in vacuo at a bath temperature of 50 to 60 [deg.] C. By lyophilization of the residue, 512 mg of the crude octadecapeptide freed from blocking radicals are obtained.

  
The 512 mg of crude peptide above are dissolved in

  
10 ml of water and the solution is chromatographed on a column

  
of 1.7 cm x about 40 cm of carboxymethylcellulose (11.25 g

  
on a dry basis of Serva, 0.63 meq / g) using an ammonium acetate buffer (2,000 ml, pH 6.0) with a linear concentration gradient ranging from 0 to 0.6 mole / 1. 10 ml fractions are collected which are observed by absorption at 280 nm and those corresponding to the main peak are pooled, then evaporated in vacuo at a bath temperature of 50 to 60 [deg.] C. The residue is lyophilized and dried in vacuo over sodium hydroxide pellets and phosphorus pentoxide to isolate it in an amount of 242 mg.

  
The 242 mg of partially purified octadecap eptide was subjected to partition chromatography on a column of

  
2.7 cm x 30 cm of Sephadex G-25 (medium grade, dry weight 50 g) using as solvent a 12: 3: 4: 6 by volume mixture of 1-butanol, acetic acid, pyridine and d 'water. 6 ml fractions are collected, the peptide content of which is observed according to the Folin-Clocalteu technique. The contents of tubes 12 to 18 and 19 to 60 corresponding to two peaks are collected separately, the mixtures are evaporated under vacuum at a bath temperature of 45 to
50 [deg.] C and lyophilized to obtain 64 mg of a fraction

  
F-1 and 170 mg of an F-2 fraction respectively. The F-2 fraction is chromatographed again exactly as above on the same Sephadex column. The contents of tubes 19 to 60 are combined, evaporated and lyophilized to obtain 120 mg of product.

  
The resulting 120 mg of peptide is subjected to purification. <EMI ID = 199.1>

  
ammonium (1.2CO ml, pH 6.0) with a linear concentration gradient ranging from 0.1 to 0.6 mol / l. 8 ml fractions are collected and those corresponding to a main peak are pooled.
(tubes 131 to 165), then they are evaporated and freeze-dried to

  
 <EMI ID = 200.1>

  
 <EMI ID = 201.1> Thin layer tography on cellulose F, Merck Company, it is determined that the product is homogeneous (reaction with ninhydrin

  
 <EMI ID = 202.1>

  
NH2 in 1 ml of an aqueous solution of 20 mg of zinc chloride. On the other hand, 18 mg of sodium chloride and 2 mg of al-

  
 <EMI ID = 203.1>

  
The two solutions are mixed to obtain a suspension of the complex of octadecapeptide with zinc.

EXAMPLE E -

  
To 0.2 ml of an aqueous acetate solution is added

  
 <EMI ID = 204.1>

  
aqueous zinc chloride 100 mM and 22 ml aqueous solution

  
 <EMI ID = 205.1>

  
benzyl alcohol and 0.8 ml disodium hydrogenphosphate
100 mM, the mixture is stirred to form a suspension. The pH of the suspension is adjusted to approximately 7.0 by adding hydroxide

  
 <EMI ID = 206.1>

EXAMPLE F -

  
 <EMI ID = 207.1>

  
(1-18) -NH2 in 0.2 ml of distilled water and add to the solution


    

Claims (1)

0.3 ml of an aqueous solution containing 2 mg of poly-L-aspartic acid (molecular weight approximately 3,000) which was neutralized to <EMI ID = 208.1> if we. 9 mg of sodium chloride and 0.5 ml of sodium dihydrogenphosphate-dihydrogenphosphate are then added to the suspension. <EMI ID = 209.1> plex. CLAIMS. 1 - Compound selected from α-aminoisobutyryl-L-tyrosylL-seryl-L-methionyl-L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycyl-L-lysyl-L-prolyl -L-valyl-glycyl-L-lysyl- <EMI ID = 210.1> ryl-L-tyrosyl-L-seryl-L-norleucyl-L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycyl-L-lysyl-L-prolyl-L-valylglycyl-L- lysyl-L-lysyl-L-arginyl-L-arginine in the form of an amide, <EMI ID = 211.1> histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycyl-L-lysyl-Lprolyl-L-valyl-glycyl-L-lysyl-L-lysyl-L-lysyl-L-lysine as amide, their non-toxic acid addition salts and their complexes. 2 - A-aminoisobutyryl-L-tyrosyl-L-seryl-L-methionyl-Lglutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophylglycyl-L-lysyl-L-prolyl-L-valyl- glycyl-L-lysyl-L-lysyl-L-lysylL-lysine as an amide. 3 - A-aminoisobutyryl-L-tyrosyl-L-seryl-L-norleucyl-Lglutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophylglycyl-L-lysyl-L-prolyl-L-valyl- glycyl-L-lysyl-L-lysyl-L-arginyl-L-arginine as amide. <EMI ID = 212.1> L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophylglycyl-L-lysyl - L-prolyl-L-valyl-glycyl-L-lysyl - L-lysyl-L-lysyl-L-lysine under amide form. <EMI ID = 213.1> prolyl-L-valyl-glycyl-L-lysyl-L-lysyl-Y where X represents an L-methionyl or L-norleucyl radical and Y re- <EMI ID = 214.1> ginyl-L-arginine in the form of an amide, however excluding octadecapeptide in the formula of which X represents the L-methionyl radical and Y represents L-arginyl-L-arginine in the form of amide, and their complexes or addition salts of non-toxic acids, characterized in that that we condense a protected decapeptide of formula: <EMI ID = 215.1> has a radical protecting the carboxyl function and X has the meaning above, with a protected octapeptide of formula: <EMI ID = 216.1> in amide form or L-arginyl-L-arginine in amide form, and the protective radicals of the protected octadecapeptide resulting from formula are removed: <EMI ID = 217.1> where all symbols have the above meanings, then the resulting octadecapeptide freed from protective radicals is optionally converted to one of its complexes or non-toxic acid addition salts in a conventional manner. 6 - Process for the preparation of α-aminoisobutyryl-L-ty-rosyl-L-seryl-L-methionyl-L-glutamyl-L-histidyl-L-phenylalanyl-Larginyl-L-tryptophyl-glycyl-L-lysyl- L-prolyl-L-valyl-glycylL-lysyl-L-lysyl-L-lysyl-L-lysine in the form of amide and its complexes or addition salts of non-toxic acids, characterized in that one condenses a protected decapeptide of the formula: <EMI ID = 218.1> phyl-glycine <EMI ID = 219.1> represents a radical protecting the carboxyl function, with a protected octapeptide of formula: <EMI ID = 220.1> the amino function, the protective radicals of the protected octadecapeptide resulting from formula are removed: <EMI ID = 221.1> where all the symbols have the above meaning, and the resulting octadecapeptide freed from protective radicals is optionally converted into one of its complexes or non-toxic acid addition salts in a conventional manner. 7 - Process for preparing c-aminoisobutyryl-L-tyrosyl-L-seryl-L-norleucyl-L-glutamyl-L-histidyl-L-phenylalanyl-Larginyl-L-tryptophyl-glycyl-L-lysyl-L- prolyl-L- / alyl-glycyl-Llysyl-L-lysyl-L-arginyl-L-arginine as an amide or a of its complexes or addition salts of non-toxic acids, characterized in that a protected decapeptide of formula condenses: R <1> -a-aminoisobutyryl-L-tyrosyl-L-seryl-L-norleucyl-YR <2> -L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl -glycine. <EMI ID = 222.1> represents a radical protecting the carboxyl function, with a protected octapeptide of formula: <EMI ID = 223.1> the amino function, the protective radicals of the protected octadecapeptide resulting from formula are removed: R -a-aminoisobutyryl-L-tyrosyl-L-seryl-L-norleucyl-Y-R L-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophyl- <EMI ID = 224.1> R5-L-lysyl-L-arginyl-L-arginine as amide where all the symbols have the above meaning, and the resulting octadecapeptide freed from protective radicals is optionally converted into one of its complexes or non-toxic acid addition salts in a conventional manner. 8 - Process for the preparation of α-aminoisobutyryl-L-tyrosyl-L-seryl-L-norleucyl-L-glutamyl-L-histidyl-L-phenylalanyl-Larginyl-L-tryptophyl-glycyl-L-lysyl-L- prolyl-L-valyl-glycyl-L-lysyl-L-lysyl-L-lysyl-L - lysine in the form of an amide or one of its complexes or addition salts of non-toxic acids, characterized in that that we condense a protected decapeptide of formula: <EMI ID = 225.1> represents a radical protecting the carboxyl function, with a protected octapeptide of formula: <EMI ID = 226.1> the amino function, the protective radicals of the protected octadecapeptide resulting from formula are removed: <EMI ID = 227.1> where all symbols have the above meanings, and the resulting octadecapeptide freed from protective radicals is optionally converted into one of its complexes or non-toxic acid addition salts in a conventional manner.