FI60209C - FREEZING FOR ALPHA-AMINOBENSYLPENICILLINER OCH SALTER DAERAV - Google Patents

Description

rRl ANNOUNCEMENT

Ma [] (1> UTLÄGGNINGSSKRIFT 60209 • λ? ® m Patent aieddelat ^ (51) K ».ik? /Int.ci.3 c 07 D 499/68, 499/12 FINLAND - FINLAND (21) P« »ntt , h * k «mu * - P * t * nt * n» eknln | 22 * 16/72 (22) Hakamisptivt - An * 6knlngid * (Qg ^ (23) AlkupiM — Glltl «h« dose 15.08.72 (41) ) Tullut JulkiMk *! - Bllvlt offantllg lA ') *.

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Patent · och registerstyrelsen An * ttk »n utl» jd och utLskriftM published 31.08.81 (32) (33) (31) Requested atuolkaut— Baflrd priority 17 * 12.71

Portugal (PT) 56966 Tot eenry et ty-Styrkt (71) "CIPAN" Companhia Industrial Produtora de Antibioticos, S.A.R.L.

Av. Comes Pereira, 7kt Lisboa, Portugal (PT) (72) Artur Pereira da Lua, Lisboa, Portugal (PT) (7 * 0 Ruska & Co (5 * 0 The present invention relates to a new process for the preparation of optionally substituted α-aminobenzylpenicillins, also called 6- (α-aminophenylacetamido) -penicillanic acids or 6 (α-aminobenzylcarboxamido) -penicillanic acids, and their salts, 0 S CH ~

Il X \ / R — CH - C - NH - CH - CH c 'I II I ^ ch3

NH2 0 == C-N-CH— I - 0 - X

wherein R is a phenyl group which may be substituted by a halogen atom or a hydroxyl group, and wherein X is a hydrogen atom, an alkali or alkaline earth metal or a triethylammonium, procainium, dibenzylammonium, N-ethylpiperidinium or N, N'-dibenzylethylenediammonium group, aminopenicillanic acid with optionally substituted α-aminophenylacetyl chloride of the general formula R - CH - I - Cl NH2 HCl 2 60209 in an aqueous medium which may contain water-miscible organic solvents at a temperature below 0 ° C at an acidic pH of the amine of the general formula I form.

The process according to the invention is characterized in that the acidic solution thus prepared is extracted with a water-immiscible chlorinated solvent, for example dichloromethane or trichloromethane, to remove organic solvents and impurities, after which the aqueous solution

In particular, this invention relates to a process for the preparation of D (-1-α-aminobenzyl-penicillin and its salts.

α-Aminopenicillins are very valuable compared to natural penicillins, due not only to their broad spectrum but also to their resistance to degradation by acids, which makes oral dosing more effective.

Many methods for the preparation of α-aminopenicillins, and in particular D (-) - α-aminobenzylpenicillin, have been reported in the scientific literature and in several patents. All industrially important methods of preparation involve the condensation of substantially 6-aminopenicillanic acid with substituted α-aminophenylacetic acid to form a peptide bond using methods well known in peptide chemistry.

What all these methods have in common is that it is necessary to activate the carboxyl group and protect the amino group of α-aminophenylacetic acid before promoting condensation.

Acid group activation and amino group protection have been extensively described in the scientific literature in connection with peptide syntheses, see, e.g., M. Goodman and G.W. Kenner, Adv. Protein Chem., 12, 465 (1967) and T. Wieland and H. Determan, Angew, Chem. Intern. Ed., 2, 558 (1963) and A. Kapoor, J. Pharm. 3ci., 5_9, 1 (1970).

3 60209

In the most commonly used methods for the synthesis of carboxylic acids in the synthesis of aminopenicillins, acid halides, anhydrides, mixed anhydrides or esters are formed. In order to protect the amino group, it is generally preferred to protect those which can be easily removed after condensation without causing the labile core of the penicillins to degrade.

The above-mentioned production methods suffer from one or more of the following disadvantages: the formation of impure products, poor yields and the need for pure reagents which are expensive or difficult to utilize on an industrial scale.

In some lesser known methods, 6-aminopenicillanic acid is condensed with α-aminophenylacetyl chloride, the amino group of which is protected to form the hydrochloride. This method has the advantage that it is possible to start with a reagent which is readily available in pure form and to avoid deprotection because the amino group can be easily liberated immediately after condensation by a simple change in the pH of the reaction medium.

However, this previously known method gives very impure products due to the presence of incomplete reaction products, decomposition products and polymers. Therefore, more or less complex, time-consuming and costly methods must be used, as some impurities can cause allergic effects in patients treated with less pure α-aminopenicillins.

In addition to dialysis followed by freeze-drying, extraction with methyl isobutyl ketone has been used, followed by separation as salts of α-aminopenicillin with arylsulfonic acids, for example g-naphthalenesulfonic acid, or sodium bis- (2-ethylhexyl] sulfosuccinate.

For example, Swedish Patent Publication 3Q1898 describes a process in which 6-aminopenicillanic acid is condensed with α-aminophenylacetyl chloride. Isolation of the final product has been described in two polymers and requires the use of additional extraction as an organic solvent with a complex salt. In other examples of aminobenzyllipenicillin, it is obtained either as an impure product 4 60209 or its presence is detected only in animal experiments or by chromatography without isolation. Yields of pure product are reported as 61.5% and 38%.

Instead, the process of the present invention achieves 88% yields.

A significant advantage of the present invention is that a complicated purification step can be avoided and not only a better yield can be obtained, but also very pure α-aminopenicillins can be obtained immediately.

The condensation step is preferably performed in a mixture of water and acetone, although other aqueous media may be used. The 6-aminopenicillanic acid may be in suspension or solution by suitably adjusting the pH of the medium. The α-aminophenylacetic acid derivative may be added in a stoichiometric amount or in an excess of up to 50%. A small excess is suitable but not essential. The condensation temperature may range from 0 ° C to -70 ° C, but is preferably in the range of -20 ° C to -4 ° C.

The solvent used in the extraction step must be immiscible with water and the partition coefficient between the aqueous phase and the organic phase must be such that a good separation is obtained. This solvent must be chosen so that the α-aminopenicillin formed is only slightly soluble in it. It is also common, although not essential, for the boiling point of the solvent to be so low that the solvent can be easily and completely removed by distillation. Suitable solvents are those which contain chlorine in their molecule, for example methylene chloride, chloroform, dichloroethane or trichlorethylene. At the end of the extraction, the volume of the aqueous phase must guarantee a sufficiently low concentration of α-aminopenicillin to prevent losses in the organic phase and a sufficiently high concentration so that a good yield is obtained in the next crystallization step. The extraction can be performed at room temperature, but it is most convenient, although not essential, that the temperature be between 10 ° C and Q ° C. The extraction is preferably carried out in two or more steps and the residual solvents in the aqueous solution are removed by evaporation at low temperature or by some other means.

5 60209

The crystallization step can take place at room temperature or at temperatures between 10 ° C and Q ° C. The choice of base used to adjust the pH of the desired α-aminopenicillin to the isoelectric point is that the salt formed by this base with the hydrochloric acid present must be highly water soluble and therefore completely removable from the mother liquors. In this case, both sodium hydroxide and aqueous ammonia can be used. The resulting crystalline product can be separated by filtration or centrifugation, followed by washing with ice-cold water. The product can also be combined with organic or inorganic bases to give the corresponding penicillinates in solution or as crystals, which bases can later be separated by known methods.

The aminopenicillins obtained by the process of this invention crystallize in high purity and do not require any further purification.

Due to this fact and the good yield, 85% of theory as a pure product, the process according to the invention is very well suited for industrial production:

The following examples illustrate the practice of the invention.

Example 1 40 g (0.185 mol) of 6-aminopenicillanic acid were suspended in a mixture of 85 ml of carbon dioxide-free water and 425 ml of acetone. After cooling to -20 ° C, 57.2 g of DL-α-amino-phenylacetyl chloride hydrochloride were added in small portions with continuous cooling and stirring and maintaining the pH at or above 2.

The mixture was stirred for 2 hours at -2 ° C and then 500 ml of acetone cooled to -5 ° C and 5 g of activated carbon were added.

After stirring for a few minutes, the mixture was filtered using a filtration aid. To the clear and colorless filtrate was added 240 ml of water and acetone was extracted twice with dichloromethane. The residual solvent remaining in the aqueous step was removed by evaporation under reduced pressure at 10 ° C. The solvent-free aqueous phase was treated with $ 30 of sodium hydroxide to the isoelectric point of DL-α-aminobenzylpenicillin.

6 60209

After filtration, washing with chilled water and drying, 57.6 g of crystalline trihydrate were obtained with an immediate purity of 96 h.

Example 2

A 5 h solution containing 40 g of 6-aminopenicillanic acid in a mixture of water and acetone (1: 1.21) was prepared by adding 6N hydrochloric acid until the pH was 1.6. After cooling to -40 ° C 300 ml of acetone were added and the mixture was re-cooled to -4 DEG C. Keeping both pH and temperature constant, 53.4 g of D (-) -? -aminophenylacetyl chloride hydrochloride were added over one hour, stirring was continued for 3 hours at the same temperature, after which the impurities 240 ml of water were added to the clear filtrate, and acetone was extracted with chloroform.The residual solvents in the aqueous phase were removed by passing the solution through a pad of granular activated carbon.The pH of the effluent was adjusted to 5 with sodium hydroxide solution. The formed crystals were filtered off and dried. -} - α-amino-benzylpenicillin trihydrate with an active ingredient of 988 ug / mg dry matter.

Example 3 To a solution of 5 g of 6-aminopenicillanic acid in a mixture of 12 ml of carbon dioxide-free water and 20 ml of acetone was added dropwise 6N sulfuric acid at 15 ° C until a complete solution was obtained. Then, 4 ml of acetone cooled to -3 ° C was added to the solution, and 5.3 g of D (-) - α-aminophenylacetic acid hydrochloride hydrochloride was gradually added with constant stirring and maintaining the pH | 1.85 · After stirring for 2 hours at -30 ° C, 55 ml of acetone were added and the solid impurities were filtered off. After the addition of water, the organic solvents were extracted in the same manner as in Example 1, and the pH of the aqueous phase was adjusted to 5 using 15% aqueous ammonia solution. To the D (-) - α-aminobenzyl-penicillin suspension thus obtained was added 160 ml of isopropyl alcohol, and the mixture was heated under reflux with constant stirring for a few minutes. After cooling and filtration, anhydrous D (-) - α-aminobenzylpenicillin was obtained as a crystalline white powder with a purity of 98%. The yield was 6.6 g (82% of theory). Example 4 To a suspension of 5 g of 6-aminopenicillanic acid in a mixture of 50 ml of carbon dioxide-free water and 80 ml of acetone was added dropwise at 15 ° C 6N hydrochloric acid until the pH was 2. After cooling to -30 ° C, 120 ml of acetone were added. .

7.1 g of D (-) - α-aminophenylacetyl chloride hydrochloride were then added in small portions, keeping the pH constant and stirring constantly.

After stirring for 60 minutes at 3535 ° C, 40 ml of acetone and 1 g of activated carbon were added. After stirring for a few minutes, filtration was performed using a filtration aid. To the colorless filtrate was added 28 ml of water, and acetone was extracted as in the previous examples. The pH of the solvent-free aqueous phase was adjusted to 9.5 with sodium hydroxide, and 2.7 g of Ν, Ν'-dibenzylethylenediamine diacetate was added to the aqueous solution with stirring. After 15 minutes, the product obtained was filtered off and washed with water to give N, N'-dibenzylethylenediamine di-6-D (-) - (α-aminophenylacetamido) penicillanate. After microbiological determination, the active substance was found to be 684 ug / mg D (-) - α-aminobenzylpenicillin, corresponding to a purity of 93% ·

Example 5

The procedure was otherwise the same as in Example 1, but using 40 g of 6-aminopenicillanic acid and 55 g of α-amino (p-hydroxyphenylacetyl chloride hydrochloride) to give 54 g of α-amino-p-hydroxybenzylpenicin monohydrate.

Analysis: found C: 50.4% \ H: 5.55% calculated · Hailia; C: 50.1%; H: 5.52%

Example 6

The procedure was otherwise the same as in Example 2, but using 0.185 moles of 6-aminopenicillanic acid and 0.195 moles of α-amino- (o-chlorophenyl) acetyl chloride hydrochloride to give 55.1 g.

Claims (3)

A process for the preparation of aminopenicillins and their salts having the general formula °. / \ Z ™ 3 R— CH - C - NH - CH - CH r I I 1 Γ », NH2 0 == C-N-CH— | - wherein X is a phenyl group which may be substituted by a halogen atom or a hydroxyl group, and in which X is a hydrogen atom, an alkali or alkaline earth metal or triethylammonium, procainium, dibenzylammonium, N-ethylpiperidinium or N, N * -dibenzylethylenediammonium group, by condensing 6-aminopenicillanic acid with the hydrochloride of optionally substituted α-aminophenylacetyl chloride of the general formula R - CH - ^ - Cl NH2 HCl in an aqueous medium which may contain water-miscible organic solvents at a general pH of less than 0 ° C to form a solution of aminopenicillin of formula I, characterized in that the acidic solution thus prepared is extracted with a water-immiscible chlorinated solvent, for example dichloromethane or trichloromethane, to remove organic solvents and impurities, after which the aminopenicillin in aqueous solution is crystallized by addition of base until pH, or by forming salts insoluble in the medium. 9 60209 Process for the preparation of D (-) - α-aminobenzyl-penicillin and its salts according to Claim 1, characterized in that D (-) - α-aminophenylacetyl chloride is used as α-aminophenylacetyl chloride. Process according to Claim 1 or 2, in which the aminopenicillin is isolated as Ν, Ν'-dibenzylethylenediammonium di-6- (α-aminophenylacetamido) penicillanates, characterized in that the crystallization is carried out by adding N, N'-dibenzylethylenediamine. r