FR2M - - Google Patents

Description

FRENCH REPUBLIC

MINISTRY OF INDUSTRY

INDUSTRIAL PROPERTY SERVICE

SPECIAL MEDICINE PATENT

P.V. n ° 829.213 International Classification:

N ° 2 M A 61 k - C 07 d

Penicillanic acids and process for their preparation.

Company known as: BEECHAM RESEARCH LABORATORIES LIMITED resident in Great Britain.

Requested on June 7, 1960, at 2.20 p.m., in Paris.

Issued by decree of November 28, 1960.

{Official Bulletin of Industrial Property [5.S.M.], No. 1 of 1961.)

{Patent application filed in the United States of America on June 8, 1959, under No. 818,506,

on behalf of Mr. Lee C. Cheney.)

The present invention relates to novel synthetic compounds useful as antibacterial agents, food supplements for animal feed, agents for the treatment of mastitis in cattle and therapeutic agents for animals, humans. and poultry, especially for the treatment of infectious diseases caused by Gram-positive bacteria.

Antibacterial agents such as benzylpe-nicillin have previously been shown to be very effective in the therapy of infections due to Gram-positive bacteria, although they have serious drawbacks, such as their instability in an acidic environment, for example during administration. oral, and their ineffectiveness against many bacteria producing penicillinase. Many of the compounds according to the invention, in addition to their antibacterial activity, show resistance to destruction by acids or by penicillinase, or else are effective against strains of bacteria resistant to benzylpenicillin.

The invention relates to acids of the general formula

(I)

Ri

Ra-CH-CO-NH-CH-

-CH

CO N-

/ sv x \ / CH3

f /

I ^ CHs

-CH-COOH

and their non-toxic salts, in which R 1 and R 2 are the same or different and represent an alkyl group containing 1 to 10 carbon atoms. The alkyl group can be straight or branched chain aliphatic, such as methyl, ethyl, n-propyl, isopropyl, ra-butyl, secondary butyl, tertiary butyl, isoamyl, n-hep-tyl and re-decyl.

The salts include non-toxic metal salts such as sodium, potassium, calcium and aluminum, ammonium and substituted ammonium salts, such as salts of non-toxic amines such as trialkylamines such as triethylamine, procaine, dibenzylamine, N-benzyl-beta-phenethylamine, 1-ephenamine, N.N'-dibenzylethylene-diamine, dehydroabiethyl-amine, N.N'-bis-dehydro-abiethyl-ethylene-dia- mine and other amines, which have been used to form salts with benzylpenicillin.

The invention also relates to a process for the preparation of compounds of general formula (I) consisting of reacting 6-amino-penicilla-nic acid, preferably in the form of a neutral salt such as the sodium or triethylamine salt, with a acid chloride of general formula

(II)

Ri

I

Ra-CH-CO-Cl in which Ri and Ro have the meanings indicated above, or its functional equivalents, as acylating agent of the primary amine group. These functional equivalents include the corresponding carboxylic acid anhydrides and anhydrides mixed with other carboxylic acids, including monoesters and in particular lower aliphatic esters of carbonic acid.

A process for the preparation of a compound according to the invention by means of a mixed anhydride of an alkyl chlorocarbonate consists in mixing an acid (the acid chloride of which is indicated above) with the alkyl chlorocarbonate and a tertiary hydrocarbonyl or aliphatic amine such as triethylamine, in an inert and preferably water-miscible solvent such as p-dioxane, with if desired a small amount of dry acetone and

1 - 41301

Price of the booklet: 1 NF

[2 MJ - 2

pure, for about thirty minutes in the cold, for example at about 4 ° C. To this mixed anhydride solution is then added a cold solution of 6-aminopenicillanic acid and a tertiary hydro-carbonylic amine such as triethylamine, for example in a solvent such as water. The reaction mixture is stirred for a period of about an hour to form the substituted ammonium salt of the desired product. The mixture can be if desired exhausted at alkaline pH using a water immiscible solvent such as ether, so as to remove unaltered raw materials. The product present in the aqueous phase is then converted into free acid, preferably cold under a layer of ether, by addition of extended mineral acid, for example 5N SO4H2, at a pH equal to 2. The acid free is then extracted by means of a neutral organic solvent immiscible with water such as ether, and the extract is optionally washed rapidly with cold water and then dried. The product present in the ethereal extract in free acid form is then converted to the desired metal or amine salt by treatment with an appropriate base, for example a free amine such as procaine or a solution of potassium 2-ethylhexanoate in dry / i-butanol. The salts are usually insoluble in solvents such as ether and can be collected neat by simple filtration.

Another method of preparing an ethereal solution of the acid form of a compound according to the invention consists of preparing an aqueous solution of 6-amino-penicillanic acid and sodium bicarbonate, adding the acid chloride and vigorously stirring at room temperature, for example for twenty to sixty minutes. The mixture is then exhausted with ether so as to remove the unaltered or hvdrolysed raw materials. The solution is then acidified to a pH equal to 2 and the free acid form of the product is extracted with ether. This ethereal extract is dried, for example by means of anhydrous sodium sulfate, and the dehydrating agent is removed, so as to obtain a dry ethereal solution from which the product can be easily isolated, preferably in the form of a soluble salt. in ether such as potassium salt. This method is applied when the acid chloride reacts with a primary amine faster than with water, which is determined by a simple test. In this process, the acid chloride can be replaced by an equimolar amount of the corresponding acid bromide or acid anhydride.

Some of the antibiotic substances obtained by the process according to the invention being relatively unstable compounds, easily undergoing chemical modifications resulting in a loss of antibiotic activity, it is desirable to choose sufficiently moderate reaction conditions to avoid their decomposition. The reaction conditions chosen naturally depend largely on the reactivity of the chemical reagent used. In most cases, a compromise has to be found between using very moderate conditions for a prolonged period and more drastic conditions for a shorter period, with the possibility of breaking down some of the antibiotic substance. .

The temperature chosen for the process for preparing the derivatives of a 6-aminopenicilla-nic acid should generally not exceed 30 ° C, and in many cases the appropriate temperature is room temperature. As the use of strongly acidic or alkaline conditions in the process according to the invention to be avoided, it seems preferable to carry out the process at a pH ranging from 6 to 9, which can be carried out conveniently using a buffer such as sodium bicarbonate solution or sodium phosphate. Regardless of the use of aqueous media for the reaction, including filtered fermentation broths containing 6-amino-peniciHanic acid in aqueous solution, organic solvents, e.g. dimethylformamide, dimethylaceta, may be used. -mide, chloroform, acetone, methyl-iso-butyl-ketone and dioxane. It is often satisfactory to add an aqueous solution of a salt of 6-aminopenicillanic acid to a solution of the acylating agent in an inert solvent and preferably in an inert water-miscible solvent such as acetone or acid. dimethylformamide. It is of course advisable to stir vigorously when there is more than one phase, for example solid and liquid phases or two liquid phases.

When the reaction is complete, the products are isolated, if desired, by the techniques applied to benzylpenicillin and phenoxymethyl-penicillin. Thus, the product can be depleted by means of diethyl ether or w-butanol at an acidic pH, and then recovered by lyophilization or by conversion to a salt insoluble in the solvent, for example by neutralization using an n-solution. potassium 2-ethylhexanoate butanol, or it can be precipitated from aqueous solution as a water-insoluble salt of an amine, or recovered directly by freeze-drying, preferably as a salt sodium or potassium. When in the form of the triethylamine salt, the product is converted to its free acid form and then to other salts, as used for benzylpenicillin and other penicillins. Thus, the treatment of such a compound of triethylamine in water with the aid of sodium hydroxide converts it into a sodium salt, and triethylamine can

"" SB

- 3

be removed by extraction, for example with toluene. Treatment of the sodium salt with strong aqueous acid converts the compound to its acid form, which itself can be converted to other amine salts, for example procaine, by reaction with the amine . The salts thus formed are isolated by lyophilization or, if the product is insoluble, by filtration. A method of isolating the product as a crystallized potassium salt consists of extracting the product from an acidic aqueous solution (for example at a pH equal to 2) by means of diethyl ether, drying the ether layer and adding at least one equivalent of a concentrated solution of potassium 2-ethylhexanoate in dry / i-butanol. The potassium salt which forms generally precipitates in the crystalline state and is collected by filtration or decantation.

The following examples, given without limitation, show how the invention can be implemented.

Example 1. - To 1.53 g (0.015 mol / g) of alphameth) Ibutyric acid (2-melhyl-re-butanoï-acid) dissolved in 30 ml of pure and dry dioxane at 10 ° C, is added 3 ml of triethylamine. After ten minutes of stirring, 2.2 g (0.016 mol / g) of isobutyl chlorocarbonate in 20 ml of dioxane are added dropwise over thirty minutes, while cooling. The solution thus obtained is stirred for one hundred and sixty minutes and, while it is at 10 ° C, a solution in 30 ml of water and ml of triethylamine of 3.46 g (0.016 g) is added dropwise over thirty minutes. mol / g) of 6-amino-penicillanic acid. The solution is stirred for thirty minutes at 10 ° C and for three hours at room temperature. After addition of 40 ml of water, the solution is exhausted twice with 100 ml portions of ether, then covered with 100 ml of ethe, r, adjusted to an acidic pH using acid 5 N sulfuric acid, which sets 6- (2-methyl- / i-butyramido) penicillanic acid free from its triethylammonium salt. The product is depleted twice with 100 ml of ether and the mixture of ethereal extracts is washed with 100 ml of water, dried for ten minutes with stirring over anhydrous sodium sulfate and filtered. . The one-time addition of 9.4 ml of dry / i-butanol containing 0.373 g / ml of potassium 2-ethylhexanoate precipitates the potassium salt of the product, which is collected by filtration, dried and weighed. then 3.60 g. It is soluble in water and decomposes on heating at 170-175 ° C. It contains the beta-lactam nucleus as shown by infrared analysis, it inhibits Staph. aureiis Smith at a concentration of 0.31 mes: / ml and on the same microorganism, by intramuscular injection in mice, it exhibits a curative dose in 50% of the subjects (DCr.o) of 4 meg / kg.

- [2 M]

Example 2. - To a solution of 1.23 g (0.0085 mol / g) of 2-ethylhexanoic acid and 1.4 ml (0.01 mol / g) of triethylamine in 35 ml of pure and dry dioxane at 10 ° C., 1.31 ml of isobutyl chlorocarbonate are added. Then a solution of 2 g of 6-amino-penicillanic acid in 1.4 ml of triethylamine in 10 ml of water and 10 ml of acetone is added over five to ten minutes. The solution is stirred for two hours at room temperature, extended with 250 ml of water and exhausted with ether, which is discarded. The aqueous solution is acidified to a pH equal to 2 with the aid of extended sulfuric acid, while cooling in an ice bath, and depleted with about 50 ml of ether. The ethereal extract containing the product, which is 6- (2-ethylhexanoamido) penicillanic acid, is dried over anhydrous sodium sulfate, and filtered. The addition of 4.7 g of potassium 2-ethylhexanoate in 40% butanol precipitates the potassium salt of the product, which is collected by decantation, which is dried over phosphorous anhydride and whose weight is of 2 g. This compound is soluble in water, it melts at 85-88 ° C, it contains the beta-lactam structure as shown by infrared analysis, it inhibits Staph. aureus Smith at a concentration of 0.31 mcg / ml and it has a DC 50 of 1.3 mg / kg by intramuscular injection in mice against Staph. aureus Smith.

Example 3. - 0.01 mol / g of di-ethylacetic acid (also called 2-ethylbu-tyric acid), 0.011 mol / g of triethylamine and 0.01 mol / g of isobutyl chlorocarbonate are stirred in 20 ml of pure, dry dioxane and 2 ml of dry acetone, for about thirty minutes at about 4 ° C. To this solution is then added a cooled solution of 0.01 mol / g of 6-amino-penicillanic acid and 0.01 mol / g of triethylamine in 20 ml of water, and the mixture is stirred for about an hour. Cold. After adding 1.0 g of sodium bicarbonate in 30 ml of cold water, the solution is depleted twice with 75 ml portions of ether, and the ethereal extracts are discarded. The aqueous solution is cooled and stirred in an ice bath, covered with 75 ml of ether and adjusted to a pH equal to 2 using 5 N sulfuric acid. ether and the aqueous solution is again exhausted with 75 ml of ether. The mixture of ethereal extracts containing the product, which is 6- (alpha.alpha-diethyl-acetamido) penicillanic acid, was quickly dried over anhydrous sodium sulfate, and filtered. Addition of 6 ml of dry β -butanol containing 0.373 g / ml potassium 2-ethylhexanoate, followed by addition of dry ether, precipitates the potassium salt of the product. After trituration with ether, the potassium salt of the product is dried in vacuo over phosphorus pentoxide, and a water-soluble powder is collected which inhibits development.

[2 M} -

ment of Staph. aureus Smith at a concentration of 0.001% by weight.

Example 4 - In the process described in Example 1, the replacement of alpha-methyl-K-butyric acid with 0.015 mol / g respectively of alpha-methyl- / i-dodecanoic, isobutyric, alpha -metbyl-re-pentoic (methylpropylacetic acid), 2.3-dimethyl-re-butvric (methylisopropylacetic acid), alpha-methyl-n-hexanoic (methylbutylacetic acid), alpha - ethyl - re-heptanoic (ethylpropylacetic acid) , aipha-re-butyl-re-hexa-noic, alpha - «.- propyl-n-octanoic, alpha-w-hexyl-n-octanoic and alpha-methyl-rc-decanoic, respectively gives the acids 6- (2- methyldodecanoami-do) -penicillanic acid, 6-isobutyramido-penicillanic acid, 6- (2-methyl- / i-pentanoamido) -penicillanic acid, 6- (2.3-dimethyl-Ti-butyramido J -penicillanic acid, 6- (2-methyl-rt -hexanoamido) -penicillanic, 6- (2-ethyl-n-hepta-noamido) -penicillanic, 6-f2-n-butyl-n-hexanoami-do) -penicillanic, 6- (2-re-propyl-re- octanoamido) -penicillanic, 6- (2-n-hexyl-n-octanoamido) penicillanic and 6- (2-methyl- / i-decano amido) -penicillanic acid, which is isolated in the form of solid potassium salts soluble in water. These compounds contain the beta-lactam nucleus as shown by infrared analysis and they inhibit Staph. aureus Smith at a concentration of less than 0.001% by weight.

ABSTRACT

1 ° Acids of general formula:

Ri ç.

1 / \ / CH3

R2-CH-CO-NH-CH CH C '

j xch3

CO N CH.COOH

and their non-toxic salts, in which R 1 and R 2 are the same or different and are alkyl groups containing from one to ten carbon atoms, and in particular:

at. 6- (2-methylbutyramido) penicillanic acid;

b. 6- (2-Ethylhexanoamido) penicillanic acid;

vs. 6- (alpha.alpha-diethylacetamido) penicillanic acid;

d. 6- (2,3-Dimethyl- / i-butyramido) penicillanic acid;

e. 6- (2-Methyl- / 1-pentanoamido) penicillanic acid, as well as their non-toxic salts.

2 ° Process for the preparation of the compounds specified under 1 °, consisting in reacting 6-amino-penicillanic acid or one of its neutral salts with an acid chloride of formula ri

!

R2-CH-CO-CI

where R1 and R2 have the preceding meanings. or with a functional equivalent thereof, as an acylating agent of a primary ami-nique group.

3 ° Mode of implementation of this process, according to which the acylating agent is a mixed anhydride of an alkyl chlorocarbonate prepared by reaction of the acid corresponding to the acid chloride with an alkyl chlorocarbonate and an amine hydrocarbon-bonyl or tertiary aliphatic, in an anhydrous inert solvent.

Company known as:

BEECHAM RESEARCH LABORATORIES LIMITED

Vicarious :

Cabinet Maulvault

For the sale of booklets, contact the Imprimerie Nationale, 27, rue de la Convention, Paris (15th).