DK143803B - 6-AMINOPENICILLANIC ACID DERIVATIVES USED AS INTERMEDIATE IN THE PREPARATION OF PHTHALIDESTES OF 6- (D (-) ALFA-AMINOPHENYLACETAMIDO) PENICILLANIC ACID OR ACID ADDITION SALTS THEREOF - Google Patents

Description

(19) DENMARK (®)

| p (12} PROCEDURE WRITING or 143803 B

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 128l / 78 (51) Intel.3 C 07 D 499/42 (22) Filing Date Mar 21 1978 (24) Race day 8 Jun. 1972 (41) Aim. available Mar 21 1978 (44) Posted Oct 12 1981 (86) International application no. - (86) International filing day (85) Continuation day - (62) Common application no. 2865/72

(30) Priority 9 · Jun. 1971, 19604/71 * GB

(71) Applicant BEECHAM GROUP LIMITED, Brentford, GB.

(72) Inventor Harry Ferres, GB: John Peter ^ Clayton, GB.

(74) Plougmann & Vingtoft's Patent Office.

(54) 6-Aminopenicillanic acid derivative for use as an intermediate in the preparation of phthalide ester of 6- (D (-) alpha-aminophenylacetamido) nicillanic acid or acid addition salt thereof.

The present invention relates to a novel 6-aminopenicillanic acid derivative for use as an intermediate in the preparation of phthalide ester of 6- [D (-) α-aminophenylacetamido] penicillanic acid or acid addition salts thereof.

ffl r / 3 6- [D (-) α-aminophenylacetamido] penicillanic acid is a commonly used broad spectrum antibiotic. However, it is constantly absorbed into the blood when administered orally. Some practitioners think that this is a disadvantage and therefore attempts have been made to find derivatives of 6- [D (") α-aminophenylacetamido] penicillanic acid, which will result in higher blood concentrations of the peni cillin in question. oral administration than could be achieved with the penicillin itself.

2 143803

It has been found that the novel phthalide ester of 6- [D (-) α - aminophenylacetamido] penicillanic acid gives a high serum concentration of the penicillin concerned when administered orally.

Phthalide ester of 6- [D (-) α-aminophenylacetamido] penicillanic acid has the formula I

/ f ~ \ <D>

// ') -CH-CO-NH-CH - CH C

W \ CEL ·

J T

NH χ 2 CO - N-CH-CO-O-CH ^

CO

II

island

A preferred acid addition salt of the compound of formula I is the hydrochloride, but salts may also be used with other inorganic or organic acids (especially those acids which can be used to form salts with the 6- [D (-) α-aminophenylacetamido] penicillanic acid). Furthermore, the compound of formula I can form salts with other penicillic acids, e.g. 3- (2'-chloro-6'-fluorophenyl) -5-methyl-isoxazol-4-lylpenicillin.

Phthalide ester of 6- [D (-) α-aminophenylacetamido] penicillanic acid or acid addition salts thereof can be prepared by:

6-Aminopenicillanic acid phthalide ester or a silyl derivative thereof is reacted with a reactive N-acylation derivative of the (D) 'isomer of a compound of general formula II

v r— CH — COOH II

\ = y i

X

wherein X represents an amino group, a protected amino group or group which can be converted to an amino group, the silyl group, when present, is removed by hydrolysis or alcoholysis and the group X, if not an amino group, is converted to an amino group. amino group under neutral or acidic conditions Accordingly, the 6-aminopenicillanic acid derivative of the invention is 6-aminopenicillanic acid phthalide ester.

The ester of formula I can thus be prepared by reaction of

6-aminopenicillanic acid phthalide ester or a silyl derivative thereof with a reactive N-acylation derivative of the (D) isomer of a compound of the general formula II

O CH-COOH II

X

wherein X represents an amino group, a protected amino group or group which can be converted to an amino group, removal of the silyl group when present, by hydrolysis or alcoholysis, and, if X is not an amino group, conversion of the group X to an amino group under neutral or acidic conditions.

By the term "silyl derivative" of phthalide ester of 6-aminopenicilanoic acid is meant herein those products which are prepared by reaction between 6-aminopenicillanphthalide ester and a silylating agent such as a halogen trialkylsilane, a dihalogen dialkylsilane, a halogen trialkylsilane or a halogen trialkylsilane, and compounds such as hexamethyl disilazanes. Usually halogen trialkylsilanes, especially trimethylchlorosilane, are preferred.

The silylated derivatives of 6-aminopenicillanic acid phthalide ester are highly sensitive to moisture and hydroxyl compounds, and upon reaction with the reactive derivative of the compound of general formula II, the acylated intermediate silyl group can be removed by hydrolysis or alcoholysis.

Examples of protected amino groups include the protonized amino group (X = NH 3) which, after acylation, can be converted to a free amino group by simple neutralization, the benzyloxycarbonylamino group (X = NH-CC 2 CE 2 Ph (Ph denotes throughout the present description CgH5)) or substituted benzyloxycarbonylamino groups which are later converted to N1 · by catalytic hydrogenation, and several groups which, after acylation, are converted to the amino group by mild acidic hydrolysis. (Alkaline hydrolysis is usually not applicable as the phthalide group is hydrolyzed under alkaline conditions.) 4 143803

Examples of groups X, which can later be converted to NH2 by mild acidic hydrolysis, include enamine groups of general formula XII

R1! yc 2 / \ R -C N-

3 I I

E -% / 1 2 where R represents lower alkyl, R represents either a hydrogen atom 13

or together with R represents a carbocyclic ring and R represents lower alkyl, aryl or lower alkoxy, and the dotted line represents a hydrogen bond, or tautomeric forms thereof and α-hydroxyarylidene groups of general formula IV

CH.

/ \ / —C N- z li: iv

V_c H

where Z represents the remainder of a substituted or unsubstituted benzene or naphtha ring, and the dotted line represents a hydrogen bond, or tautomeric forms thereof.

An example of a group X which can be converted to NH2 after acylation of phthalide ester of 6-aminopenicillanic acid with the reactive derivative of the general formula II is the azido group. In this case, the final conversion to NH 2 can be accomplished either by catalytic hydrogenation or by electrolytic reduction.

A reactive N-acylation derivative of the general formula II is used in the above procedure. The choice of the reactive derivative, of course, depends on the chemical property of the α-substituent X. Thus, when X is an acid stable group such as a protonized amino group NH 4 or the azido group, it is often convenient to convert the acid of the general formula II to an acid halide, e.g. by treatment with thionyl chloride or phosphorus pentachloride to form the acid chloride.

However, such reagents will be avoided when X is an acid labile group of general formula III or IV. In such cases, it is often convenient to use mixed anhydrides. For this purpose, alkoxy formic anhydrides, which are conveniently prepared by treating an alkali metal or tertiary amine salt of the acid of the general formula II with an appropriate alkyl chloroformate in anhydrous medium or at room temperature, are particularly suitable mixed anhydrides.

Other reactive N-acylation derivatives of acids of general formula II include the reactive intermediate formed by reaction in situ with a carbodiimide or a carbonyl diimidazole.

6-Aminopenicillanic acid phthalide ester can be prepared - albeit in low yield - by direct coupling of 6-aminopenicillanic acid with 3-bromo-phthalide in the presence of base. With this process, some epimerization occurs at Cg, and the process is therefore not entirely satisfactory.

Significantly better yield of 6-aminopenicillanic acid phthalide ester can be obtained by coupling an N-protected derivative of 6-aminopenicillanic acid (e.g. triphenylmethyl derivative) with 3-bromophthalide and subsequent removal of the protecting group (e.g. by mild acidic hydrolysis, if the triphenylmethyl derivative is used).

Alternatively to N-protected 6-aminopenicillanic acid, 6-acylaminopenicillanic acids may be used. Methods for removing the 6-acyl side chain from benzylpenicillin and phenoxymethylpenicillin are known (e.g., British Patent Specification No. 1,189,022) and usually comprise treating an ester of 6-acylaminopenicillanic acid with PCIg to form an iminochloride bond on 6-amidone nitrogen. by treating the imino chloride with an alcohol to form an imino ether and subsequently hydrolyzing the imino bond to form the 6-aminopenicillanic acid ester. In the present case, it is possible to base on phthalide ester of penicillin G or penicillin V

c. 143803 6 (for example, prepared by reacting the sodium or potassium salt of the penicillin with 3-bromophthalide) and cleaving the acyl chain to prepare phthalide ester of 6-aminopenicillanic acid.

The compound of formula I is well tolerated and preferably administered orally, optionally in the form of an acid addition salt. Usually it is administered together with useful pharmaceutically tolerable carriers. In such compositions, the compound may comprise between 1 and 95% by weight of the total composition. The composition may be in the form of a powder for use in the form of a syrup, in the form of tablets, capsules or pills or any other usual form.

The ester of formula I or salts thereof may conveniently be administered in unit doses having a content corresponding to 0.025 - 1 g of 6- [D (-) α-aminophenylacetamido] penicillanic acid, preferably corresponding to 0.1-0.7 g of penicillanic acid. Unit doses containing an amount corresponding to 250-500 mg of the subject penicillanic acid are appropriate. The daily dose depends on the condition of the patient, but usually 1 - 3 g of the ester, calculated as the subject penicillanic acid, will be appropriate.

6- [D (-) α-Aminophenylacetamidojpenicillanic acid phthalide ester is well absorbed when administered orally to humans and animals. High serum values of the underlying 6- [D (-) α-aminophenylacetamido] penicillanic acid are obtained.

Danish Patent Application No. 2757/72 discloses oxofuryl esters of 6- (α-aminophenylacetamido) penicillanic acid. Priority parents in relation to the present application are only generic ones with a monocyclic saturated ring in the ester moiety and specifically only the compound 5-oxo-tetrahydro-2-fury ester of ampicillin. This priority compound from Application No. 2757/72 is designated in the table below II, while 6- [D (-) α-aminophenylacetamido] penicillanic acid phthalide ester is designated I.

The table contains results of determining the blood level of ampicillin in mice after oral administration of Compound I (prepared from the intermediate of the invention) and Compound II (Priority Elderly, respectively) at a dose of 50 mg / kg ampicillin free acid.

143803 7

Table

Compound No. Test No. Concentration (mg / ml) minutes after dosing 30 60 120 240 I 1 2.15 4.2 0.55 0.28 1.8 3.25 0.88 0.30 3.0 1.9 1, 05 0.41 2.15 - 0.96 0.31 2.25 - 1.15 0.20 2 4.2 5.4 1.9 1.7 2.0 2.3 0.45 0.05 2.9 0, 86 0.32 0.08 2.7 0.72 0.64 0.04 1.6 1.6 1.5 1.3 Average 2.48 2.53 0.94 0.47 II 1 1.35 0 97 0.19 0.15 2.9 0.80 0.33 1.15 1.05 0.98 0.32 0.30 3.0 0.87 0.46 0.22 1.0 0.88 0.33 2 1.65 0 , 68 1.9 0.09 1.65 1.6 0.2 0.44 1.6 0.5 0.22 0.14 1.3 0.41 0.71 0.12 1.7 0.52 0.11 0 , 78 average 1.72 0.82 0.48 0.27 "M ~ '' '' I- ·» ·· -..............,, II .... ..........

0 143803

ISLAND

The results show that the concentration of ampicillin in the blood is significantly higher after administration of compound I than after administration of the priority compound.

The invention is further illustrated by the following examples:

Example 1.

The phthalide of 6-aminopenicillanate.

Method 1.

A mixture of 10.8 g of 6-aminopenicillanic acid (0.05M) and 6.9 ml of triethylamine (0.05M) is stirred in 20 ml of dry acetone for 0.5 hour at room temperature. The mixture is cooled to 0 ° C and in one portion a solution of 10.65 g of 3-bromophthalide (0.05M) in 20 ml of dry acetone is added and the resulting yellow mixture is stirred at room temperature for 5 hours. The reaction mixture is diluted with 150 ml of dry diethyl ether and filtered. The clear yellow filtrate is washed with 100 ml of 1 N sodium bicarbonate solution and with 100 ml of saturated brine. To the clear yellow filtrate is added 9.5 g of a solution of p-toluenesulfonic acid monohydrate (1 equivalent) in 150 ml of dry acetone, and the phthalide of the epi-6-aminopenicillanate in the form of the p-touenesulfonate salt crystallizes immediately from the solution.

6-α trans isomer: NMR [(CD CD ^^ SO]: L δ = 7.84 (4H, aromatic phthalide), δ = 7.58 (1H, CO-O-CH), δ = 7.30 (4H, aromatic sulfonate), δ = 5.35 (1H, C-5 proton, J = 2Hz), S = 4.89 (1H, C-3 proton) , δ = 4.70 (1H.d.

C-6 proton, J = 2Hz), δ = 2.30 (3H, CH3) and δ = 1.48 (6H.d. average - di-CH3). IR (KBr) strong bands at 1780 cm \ 1210 cm \ 1170 cm 1010 cm 970 cm 682 cm ^ and 574 cm ~ ^.

From the mother liquor is obtained some additional oil, from which a small amount (about 5%) of a fairly pure sample of the natural cis-isomer of phthalide of 6-aminopenicillanate in the form of the p-toluene sulfonate salt thereof is obtained by repeated fractionation. crystallizations of the 6-α-trans isomer of a solvent mixture of acetone / ether (3: 1).

Δ = 7.84 (4H, aromatic phthalide), δ = 7.58 (1H, s. CO-O-CH ), 6 = 7.30 (4H, aromatic sulfate), 6 = 5.50 (1H.d.

C-5 proton, J = 4Hz), δ = 5.14 (1H.d. C-6 proton, J = 4Hz), δ = 4.68 (1H, C-3 proton), δ = 2.27d (3H, CH ·,) and δ = 1.53 (6H.d. gem-di-3 -1 -1 -1 methyler). IR (KBr) strong bands at 1780 cm, 1210 cm, 1170 cm, 1010 cm 2, 970 cm 682 cm 2 and 574 cm Method 2.

A solution of 9.8 g of 6-tritylaminopenicillanic acid (0.02M) in 100 ml of dry acetone is cooled to 0 ° C, added 2.9 mg of triethylamine (0.02M) followed by 4.1 g of 3-bromophthalide (0 (2M) in 20 ml of dry acetone and the reaction mixture is kept at 0 ° C with stirring for 2 hours and then at room temperature for 1 hour. The precipitated triethylammonium bromide is removed by filtration, the evaporated filtrate is dissolved in 150 ml of ethyl acetate and, after washing with 2 x 150 ml of cold 2% aqueous sodium bicarbonate solution and 2 x 100 ml of ice water, the ethyl acetate phase is dried over anhydrous magnesium sulfate to give the phthalide tritylaminopenicillanate is obtained in the form of a white amorphous solid by removal of the solvent in vacuo.

NMR [(CD ^) ₂S °]! ^ = 7.4 (20 H broad singlet with smaller shoulders at δ = 7.80 (aromatic protons and CO-O-CH-), S = 4.41 (2 H.m. β-lactam protons), δ = 4 , 15 (1H broad singlet C-3 proton) and δ = 1.38 (6H.d. gem dimethyler).

IR (KBr) strong bands at 1745 cm 980 cm -1, 750 cm 3 and 708 cm 5.9 g phthalide of 6-tritylamineopenicillanate (0.01M) in 200 ml acetone containing 0.2% water are treated with 1 9 g of p-toluenesulfonic acid monohydrate (0.01M). After standing for 2 hours at room temperature, 0.25 ml of water is added and by slowly adding 250 ml of petroleum ether (boiling range 40 - 60 ° C), phthalide precipitate of 6-aminopenicillanate-p-toluenesulfonate is obtained. By filtration and subsequent washing with petroleum ether, the crude p-toluenesulfonate salt is obtained.

The sample is recrystallized from acetone / diethyl ether (85% recovery).

NMR [(CD--SO SO]: δ = 7.84 (4H, aromatic phthalide), δ = 7.58 (1H, s. -CO-O-CH-), δ = 7.30 (44 , 9 q. Aromatic sulfonate), δ = 5.50 (1H.d. β-lactamer, J = 4Hz), δ = 5.14 (1H.d. β-lactam, J = 4Hz), 143803 δο 6 = 4.68 (1H, C-3 proton), δ = 2.27 (3H, CH3) and δ = 1.53 (6H.d. gem dimethyler).

Analysis:

Calcd for C 23 H 24 N 2 S 2 O 8: C 53.08 H 4.61 N 5.39 S 12.31 Found: C 52.32 H 4.60 N 4.94 S 12.27.

Method 3.

Benzylpenicillinphthalidester.

20.0 g of the potassium salt of benzylpenicillin (10,054 mol) is dissolved in 50 ml of dry dimethylformamide and cooled to 0 ° C. To this solution is added, with stirring, 11.5 g of 3-bromophthalide (0.054 mol) in 20 ml of dry dimethylformamide in one portion. The temperature of the reaction mixture is allowed to rise to room temperature and the mixture is stirred for a further 2 hours. The mixture is poured into 600 ml of ice-cold water and stirred vigorously. The white solid precipitate, which separates, is collected and washed thoroughly with water. After drying, the substance is recrystallized from hot isopropanol to give 10.5 g of white crystalline product (41.9%), mp 167 - 169 ° C. The IR spectrum (nujol) contains strong bands at 1770 cm \ 16 1678 cm * ", 1524 cm ^ og and 970 cm NMR [(CD CD) ₂SQ / D₂O] contain peaks at: δ = 7.88 (4Hm aromatic phthalide), δ = 7.61 (1H.s. CO-O-CH-), δ = 7.28 (5H.s. Aromatics), δ = 5.55 (2H.m. 0-lactamer), δ = 4.55 (1H.s. C C-proton), δ = 3.56 (2H, PhC 2 CO) and δ = 1.53 (6H.d. gem dimethyler). The purity determined by hydroxylamine is 109.2%.

Analysis:

Calcd for C24H22N2SO6: C, 61.55; H, 4.90; W, 5.87; S, 6.72. Found: C, 6.80; H, 4.72;

Dissolve 11.6 g of benzylpenicillin phthalide ester (0.025M) in 250 ml of dry methylene dichloride and cool to -25 ° C. 5.60 ml of N-methylmorpholine (0.025M) is added followed by a solution of 6.0 g of phosphorus pentachloride in 150 ml of methylene dichloride over 5 minutes. A pale yellow color develops and after stirring for 0.5 hour the temperature rises to 0 ° C. The reaction mixture is cooled to -25 ° C, and 5.60 ml of N-methylmorpholine and dry methanol are added, giving a slow steady rise in temperature until approx. -10 ° C.

143803 11

After stirring at a temperature of -5 to 0 ° C for a further 2 hours, 400 ml of water is added with vigorous stirring while adjusting the pH of the mixture from 1.2 to 6.0 with dilute sodium hydroxide solution.

The organic phase is separated, washed with water and with a saturated saline solution and filtered through silicone paper.

4.75 g of a solution of p-toluenesulfonic acid monohydrate (0.025M) in 100 ml of acetone is added with stirring to the organic phase and ether is added until the solution becomes cloudy. On standing overnight at 0 ° C, 7.0 g of white crystals of 6-amino * -penicillanic acid phthalide ester p-toluenesulfonate are obtained and an additional 2.5 g is obtained by concentrating the filtrate. The total yield is 9.5 g (73.4%).

NMR [(CD ^^ SO SO]: δ = 7.84 (4H, aromatic phthalide), δ = 7.58 (1H, s. -CO-0-CH-), δ = 7.30 (4H. s. aromatic sulfonate), δ = 5.50 (1H. d. (3-lactam, J = 4Hz), δ = 5.14 (1H.d. β-lactam, J = 4Hz), δ = 4.68 (1 H, C 2 -proton), δ = 2.27 (3 H, CH 3 -) and δ = 1.53 (6 H.d. gem-di-CH 3).

Analysis:

Calculated for <-23H24I ^ 2 ^ 2 <^ 8! C 53.08 H 4.61 N 5.39 S 12.31 Found C 52.50 H 4.62 N 4.98 S 12.34.

Example 2.

Ampicillin phthalide ester (I) via coupling of phthalide of 6-aminopenia cillanate with a mixed anhydride of enamine protected α-aminophenyl acetic acid.

<D> (D> f ') -CH-CO 2Na (f) -CH-CO-0-CO-0C

\ - / I I

CH3 ”9? CH -.- C H

I: -> 3 I! J3 CH 0 \ c '\ ^ r y NCx 6 ~ aminope- I I \ nicillan- AND ·, JL „\ syrephtha- j utii3 \ member 143803

-CHCO-NH -, J-S

pH 2.5 | -Nv (I) 4- CH 3 - / o ^ ii in CH 0/1 \ / I> 1 I o and 3 10.4 g of phthalide of 6-aminopenicillanate p-toluenesulfonate is suspended in 60 ml of ethyl acetate and stirred vigorously with 135 ml of IN sodium bicarbonate solution for 20 minutes at room temperature. The organic phase is separated, washed with 100 ml of water containing 5 ml of 2% sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered and maintained at -15 ° C.

5.4 g of a mixed anhydride of sodium D (-) N- (1-methoxycarbonyl-propen-2-yl) -α-aminophenyl acetate in 30 ml of ethyl acetate is prepared by adding 2 ml of ethyl chloroformate and 2 drops of pyridine at -15 ° C. and stirring the reaction mixture for 10 minutes at a temperature between -15 and -20 ° C. To this solution of a mixed anhydride is added the ethyl acetate solution of the phthalide of 6-aminopenicillanate and the mixture is stirred at -15 ° C for 15 minutes and then further for 45 minutes without further cooling.

75 ml of water is added, followed by 10 ml of 2N hydrochloric acid and the reaction mixture is stirred vigorously for 25 minutes. 250 ml of petroleum ether (boiling range 60 - 80 ° C) is slowly added with stirring. The aqueous phase is separated and saturated with sodium chloride, and the separating oil is extracted with 2 x 100 ml of ethyl acetate and dried over anhydrous magnesium sulfate.

After filtration, the solution is concentrated in vacuo to ca. 1/4 volume, slowly added approx. 250 ml of dry ether and the ampicillin phthalide, which precipitates in the form of 4.0 g of white amorphous hydrochloride salt (40%), are collected and washed thoroughly with ether. Hydroxylamine analysis gives 76.1%, iodometric analysis gives 77.5%, and the chlorine content is 7.07% (theoretical 6.85%).

Attempt.

The rate of hydrolysis of phthalide ester of 6- [D (-) α-aminophenylacetamido] penicillanic acid hydrochloride is determined by adding the ester in an amount equal to 5 ml of 6- [D (-) α-aminophenylacetamido] penicillanic acid to 0.05M potassium phosphate buffer at a pH of 7.0, to 901 human blood and to 90% death head blood.

The ester was also tested for hydrolysis in a small intestine monkey homogenate at a concentration equal to 100 µg per day. ml of 6- [D (-) α-aminophenylacetamido] penicillanic acid and the reaction mixture is diluted to a concentration equal to 5.0 µg / ml. prior to analysis. The tissue homogenate is prepared by homogenization of washed laryngeal intestine in the 4-fold by weight of 0.05M potassium phosphate buffer. The reaction mixture is prepared by further dilution (1:10) of this preparation.

All the reaction mixtures are incubated at 37 ° C. After incubation, the ester is separated from the reaction mixture by electrophoresis. On starch agar gel plates buffered to a pH of 5.5 are placed 5 µl of a suitable dilution of the reaction mixture and 6- [D (-) α-aminophenylacetamido] penicillanic acid standards prepared in an appropriate manner. medium. Above the plates, a potential of 15 volts per cm for 20 minutes. At this pH, the penicillanic acid in question becomes close to its original site, and any ester present moves toward the cathode. The amount of penicillanic acid present in the reaction mixture is determined by pouring the gel plates with a nutrient agar (bovine ground agar) seeded with Sarcina lutea NCTC 8340 and incubating for 16 hours at 30 ° C. The inhibition zones of ampicillin in the samples and standards are measured and the amount of penicillanic acid in question formed by the reaction is determined.