DE1670022A1 - Process for the production of semi-synthetic penicillins and their non-toxic salts - Google Patents

Description

Dr. Ing. E. BERKENFELD · Dipl.-Ing. H. BERKENFELD, patent attorneys, Cologne Attachment file number

on the submission of Feb. 2, 1968 Nam «d. Note Ankerfarm J.p.A.

'/ experienced in the manufacture of semi-synthetic penicillins and their non-toxic salts.

The invention relates to the production of semi-synthetic penicillins and their non-toxic salts. These compounds have the general formula

R-NH-CH-CH

CH CO N CH - COOH

in which R is an amino-substituted acyl group of the formula R '- (CH ₂ ) _n - CH-CO- _(II)

R "- NH

in which R ^{1 is} H, -NH ₂ * -COOH, mono- or polysubstituted alkyl, arylalkyl or a heterocyclic group; R "is (CH ₂ ) _n and η is zero or an integer up to 5.

Since the penicillins obtained by the process of the present invention have an asymmetric carbon atom, viz the atom to which the amino group is attached relates to the

Finding both optically active D (-) and L (+) forms.

Penicillins are known from British patent specification 373 049, which have a general formula analogous to the formula I listed above and the particularly antibacterial activity against gram-positive and gram-negative organisms, These penicillins can be used with advantage as feed additives will.

Because these connections have a remarkable resistance against degradation by acids produced in the gastric juices, their use for therapeutic purposes per os is to recommend.

According to the process of the invention, an organic salt is obtained 6-aminopenicillanic acid with the N-carboxyanhydrides of the amino acids of the formula II in a suitably hydrated medium implemented that at low temperature a certain specific dangerous for the molecular structure of the antibiotics Has conductivity, and the reaction kinetics is determined by means of a catalyst and suitable physicochemical conditions elevated.

The particular features of the present invention are as follows.

As known, for example, from Greenstein and Winitz "Chemistry of the Amino Acids, Vol. II, John Wiley 4 Sons, Inc., NY, the N-carboxyanhidrides of the amino acids, because of their pronounced instability, require special precautions with regard to the

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ienden acyl grounding agent. - ^

This fact limits their application particularly on an industrial basis. Attempts have been made to overcome these disadvantages by means of various aids; It has proven most successful to carry out the acylation reaction in a medium stabilized by the addition of suitable buffer mixtures. However, the components iiesei · mixtures must once the reaction has been completed _/ to be removed from learning medium, as they could interfere with the production of antibiotics by passing the reaction mixture eg by very active deionizing resins.

These working methods prevent the use of N-carboxyanhydride on an industrial basis and thus lead to a reduction in the yield of penicillins. Especially when using deionizing Reduction occurring in resins can be attributed to adsorption phenomena, which are hardly ever practical Extent can be reversed.

It has been found that a notable catalytic effect on the acylation is achieved if the acylation reactions between the N-carboxyanhydrides of the amino acids indicated above and the 6-aminopenicillanic acid in the presence of 2,4-lutidine A or an analogous, a cyclic structure having carried out organic base, this' being present as a free base in excess.

The mechanism of this catalytic effect cannot as yet be clearly explained; but it is characteristic that the yields of the acylation urase compositions are clearly higher when

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different salt-forming, organic or inorganic Baden, which, as in the present case, is a cyclical, polycyclical or have a linear structure.

The use of 2,4-lutidine or an analogue organic Base rr.with a corresponding cyclic structure in a larger than stoichiometric amount as a JmIz-forming agent for 6-aminopenicillanic acid proves to be highly effective as a buffering medium in the acellation reactions of the present invention. This buffering effect develops at a pH in the range of 6.9 and 3 », i.e. at a value of .7ert, which has a good resistance to the used N-carboxyanhydrides of the amino acids guaranteed.

The organic breasts used in the method of the invention cyclic structure can after completion of the reaction by means of a strong basic acid and a subsequent one Use of an inert water-immiscible solvent, in which the penicillin obtained is practically insoluble, can be removed. The use of an inert water immiscible solvent allows the removal of substances that have not fully reacted, polymerized or decomposed by dissolving them or converted into an easily filterable form by agglomeration.

and
In the aqueous phase that has been purified / consequently stratified in this way, the penicillin remains in a concentration sufficient to cause it to crystallize at its characteristic isoelectric point. In order to achieve a quick implementation at sufficiently low temperatures, in order to avoid

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that the sensitive newly formed molecules suffer damage, 33 is very important as was found out of the mix that to remove carbon dioxide formed, which can be done by waning the reaction mixture at a much lower level holds than necessary for saturation at normal working temperature.

For this purpose, totally dry and oxygen-free nitrogen (equal to 6O mm Hg ximaler% by mass of residual pressure) led reaction mixture held in fine bubbles through the cooled to low temperature, and vigorously stirred under a high vacuum. Active charcoal is also suspended in the reaction mixture as an adsorbent, which enables complete removal of the carbon dioxide formed.

The reaction indicated above can be carried out in the manner indicated above carried out even in an inert, weakly hydrated medium that does not have a specifically high conductivity as required by the instability of the N-carboxyanhydrides of the amino acids given above.

The synthesis temperatures are in the range of -10 - -5 C, i.e., within a temperature range easily achievable when carrying out the process on an industrial basis is.

The process for obtaining and purifying the semisynthetic penicillins obtained according to the invention is very simple and leads to high yields of products with good microbiological activity. * "*" "- 5 -

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In the following examples, the .srfin-ix is. ■ described in more detail.

Example 1

3s, 1.2 mole of N-carboxyanhydride of DL-alpha-amino-phenylacetic acid dissolved in toluene and the solution cooled to -10 C ^J.

In a special approach, a 23% aqueous solution of 1 mol of 6-aminopenicillanic acid (100; j) and 2 mol of 2,4-lutidine was prepared and the solution was cooled to -10.degree. The two solutions were then mixed with vigorous stirring while maintaining a temperature of -10 ° C. and charcoal, which had previously been saturated with 2% carbon dioxide under toluene, was added to the resulting solution 2, "J. With constant stirring, a stream was completely dry and oxygen-free nitrogen bubbled through the reaction mixture by means of a plate of porous Jenaglas, the pressure of the reaction raunies being kept at about oQ mm of mercury. The reaction would be chromatographed "on plates of silica gel and using an alcoholic solution of ninhydrin up to Disappearance of the

6-the / aminopenicillanic acid traced the stain formed.

Then, the feed is interrupted by nitrogen, and the Re nude ionsgemisch on customary printing gebraiit and then at 0 ⁰ C. The reaction mixture is reacted with 40 $ strength by weight sulfuric acid to eh pH of 1.5; an equal amount of butanol is added, strongly geeine

stirs, filtered with the help of filter paper and ** r & h layer formation let go on. After the organic phase has separated off, it is washed with water and then drained off. the

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ν, -ä .; zr ige.η .sauren phases are combined, ir.it two percent HoIz-> :.) hl-2 discolored uni :: it JSO.'iiger Natriuinhyiroxydlösung to a pH v -;.! -. _ ''.Iirirje.jt'ilit. After de. in standing at 2 ° C -for 24 3tuni-ii; -dri i-2r crystalline ·. * solid filtered, with SisKasser gev, -. i3Cheri uni d.-inn in a stream of air at about. 50 ° C dried.

white has a very fejsüitie appearance and an iodio-

. .etrisch '-. v. Test gives 8; ' - ro, - anhydrous alpha-air.inobenzyl- ■ „-iiioillln un! 'Γ - 15 /' .Ϊ ater y üj determination took place after

The Veriuironspro.lukt '»^ urle on a thin, 0.5 r ,: m thick .311 ika ^ ol- i.'hieiit-Chromatoplatte checked and i: .it Batanol-V / ater- ^ Döi ^ oäur-i Li-: ratio 40i50j10 developed and rr.it an alkoii-i.ioohen ^ csciit; siehtbar of Kinhydrin geniachtj it was found ei: i only F.ecken with Rf 0.35 ~ Oj ⁴ - same as a Pro '; e dieivnieii DL-a-ipha-aminobenzylpenicillin trihydrate

(c 0.32

found C = ^ l, $ 2 ; t

H = 6.45

H = 10, .1S ■ ■ 3 = 6.72

calculated C - 47.6 %

H = 6.3 N = 10.4 3 = 7.9

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Example II

It was as indicated in Example I of W-carboxyanhydride N-alpha-aminophenylacetic acid implemented.

The final product was subjected to an iodometric and n.icrobial analysis and subjected to thin-layer chromatography and found that it was DL-alpha-ansinobenzylpenicillin trihydrate.

Example III

It was as indicated in Example I N-carboxyanhydride des DL-Nor ^ aLins implemented.

The product of the process was tested iodometrically and a chromatographically Subject to learning analysis. 3s showed that there is DL-alpha-arr.inobjtylpenicillin v; ar.

Elemental analysis:

found . C = 47, ^ 5 H = 6.35 N = Ό.75 3 = 10.10

calculated C = 47 J

". 'H = 6.63

-N = 13.9-. 3 = 10.6

Claims

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Claims (1)

'- P a te η tans claims 1 . Methods for making semi-synthetic penicillins of the general formula R-NH-CH-CH C ^ '(I) CO - N CH - COOH and their non-toxic salts in which R is an amino-substituted acyl group of the general formula R ¹ - (CHoL -CH-CO-
c η, R "- NH in which R ^{1 is} either H or -NHp or -COOH or a mono- or poly-substituted aryl, alkyl, an arylalkyl group or a heterocyclic group and R "" ( ^CIi ₂ ) and η is an integer from 0-5 , characterized in that 6-amino-penicillanic acid is reacted in the presence of excess 2,4-lutidine present as a free base or an analogous cyclic organic base with the N-carboxy anhydride of an amino acid at a degree of hydration of 8-12 $ of the reaction medium. 2. The method according to claim 1, characterized in that 1Ö9809 / 2133 the reaction is carried out at -10 ° - -5 ° C. J5 · Process according to claims 1 and 2, characterized in that » that a pressure of about 60 mm Hg is maintained above the reaction mixture and through the reaction mixture Bubble through dry and oxygen-free nitrogen runs. 4. The method according to claims 1-J5, characterized in that that after completion of the reaction, the reaction mixture is adjusted to a pH of 1-5 and with an inert, with Absorbs water immiscible solvent in which unreacted reactants, products of secondary decomposition reactions or polymerized products are soluble, while the penicillin obtained is almost insoluble. 5. The method according to claim 4, characterized in that that the water-immiscible solvent is n-butyl alcohol or secondary butyl alcohol is used. - 10 -