DE2730579A1 - METHOD OF MANUFACTURING CEPHALOSPORIN ANTIBIOTICS - Google Patents

Description

PATENTANWÄLTE 2 / s3 U ü / <J PROF. DR. DR. J. REITSTÖTTER DR.-ING. WOLFRAM BUNTE DR. WERNER KlNZEBACH D-SOOO MUNICH 4O. MAUEItSTIIASSE 22 FERNRUF (Οββ) 37 ββ 3 TELEX Β21β2Οβ ISAM O

d-sooo Munich 43. fostfach7 * o

I Munich, July 6, 1977 *

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PIERREL S.p.A. Via Turati, 30, 20121-Milan, Italy

Process for the manufacture of cephalosporin antibiotics

The present invention relates to cephalosporin antibiotics and an improved method for their manufacture. In particular, the invention relates to an improved process for the acylation of 7-aminocephalosporanic acid (7-ACA) and their derivatives of the general formula I:

(D

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where X has the meanings

N N N N

-.JL.J.-.- JL., "

or -OCOCH ₃

CH.

owns, on an industrial scale, to the desired
Making cephalosporin antibiotics in a more economical way.

The object of the present invention is to create an improved production process for semisynthetic; Antibiotics by acylating 7-ACA and similar derivatives ί with highly hydrolyzable acyl halides in the presence of
Water. In the manufacture of semi-synthetic antibiotics, 7-ACA and similar derivatives can be mixed with acyl halides, symmetrical acid anhydrides, mixed anhydrides or with the free
Acid and various reactants react, resulting in cephalosporin compounds which are found to be effective
Broad spectrum antibiotics against gram-positive and gram-negative
Microorganisms have been shown. An example of such a compound is cephalotin, which is produced by the condensation of
2-thienylacetyl halide is made with 7-ACA.

A specific embodiment of the present invention is

to provide an improved method of manufacture

of sodium cephalotin, a heterogeneous mixture i being used, namely a water-immiscible organic solvent, water and a water-soluble base such as j sodium hydroxide, sodium carbonate, sodium hydrogen carbonate or! similar inorganic compounds or organic amines,
such as triethylarain and the like. ■

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Another major advantage of the invention is that
j if desired, the 7-ACA is acylated at pH 7 j

which reduces the rate of hydrolysis of the acetoxy group ' ; in 3-position, which under acidic conditions both at; ι starting product as well as the cephalosporin compound

is very rapid, is reduced.

'■

Further objects, embodiments and advantages of

Invention are apparent from the description below. ^;

According to the invention, cephalosporin antibiotics, such as j

Cephalotin, can be produced in improved yields, ' by making 7-ACA dissolved in water using a

Base, at a mild temperature using a;

j acyl halide (e.g. 2-thienylacetyl chloride) j

j acylated in the presence of an organic solvent, '·

j until the desired cephalosporin product is formed and

then the cephalosporin from the resulting reaction- j! mixture isolated.

For best results it should be organic or
inorganic base in amounts of 1 to 4 molar equivalents
be present per mole equivalent of 7-ACA.

The acylating agent should be in the reaction mixture
at least in equivalent molar amounts based on 7-ACA
to be present. However, preference is given to using an excess
of acyl halide up to 100% to a practically complete
Ensure 7-ACA response.

The choice of organic solvent used to dissolve the
j acyl halide is used, the yields can be decisive
affect and should depend on the water solubility
ι of the same can be chosen, since water quickly removes the acyl halide
^! hydrolyzed and the complete formation of cephalosporin
: Antibiotics due to a competitive reaction prevented what

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■ makes the use of such a large excess of acyl halide necessary that the process is no longer economical.

Solvents preferred according to the invention are therefore the solvents which are immiscible with water, in particular ^! especially those in which water has a solubility less than 0.1%.

In general, two classes of solvents are used, namely hydrocarbons (benzene, toluene, xylene, hexane [and the like) and halogenated solvents (methylene dichloride, chloroform, dichloroethane, carbon tetrachloride and the same).

The total amount of solvent used is for that

j Implementation process not critical, but may be dependent; of the chosen method of obtaining the antibiotic ge * · ^! be chosen.

When carrying out the acylation according to the invention. reaction, it is advisable to first dissolve the 7-ACA and similar: derivatives in water, at least

the stoichiometric amount of a base used, which ; from a large number of inorganic bases, expedient-

wise sodium and potassium derivatives, or organic bases such as aliphatic tertiary amines, can be selected up to temperatures between
from 6 to 8 is reached.

up to the pH value at temperatures between 0 ^° C. and 30 ^{° C.}

After dissolving the 7-ACA and filtering it off, if necessary To remove any impurities present, add to the stirred 7-ACA solution at a sufficient rate (in about 0.5 to 2 hours) »to allow chemical decomposition of the reactants or the cephalosporin product avoid the one dissolved in a suitable solvent

70 9 8 8 2/1 0 6ΊΓ

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Acyl halide at a temperature between about 0 ° C and 35 ⁰ C to, forming the Cephalosporinprodukt.

I.

j The pH is kept constant at 6 to 7 by adding solid or \ dissolved sodium (or potassium) carbonate or -hydrogen-!

! carbonate adds to the formation of hydrogen halide j

j;

: to neutralize and the failure of those not implemented ■ 7-ACA and at the same time the hydrolysis of the methylene acetoxy

group, both of the starting material and the cephalosporin

compound, such as cephalotin, to prevent. '■

In this process it is not necessary to use distilled acyl halide as the colored impurities present are removed by treatment with activated carbon can and the presence of traces of thionyl chloride the Yields not reduced as the reaction is carried out at neutral pH.

i After the addition of the acyl halide has ended, j the reaction mixture is preferably stirred until a possible! full implementation is achieved. ;

Then the reaction mixture obtained from the acylation alternatively treated as follows:

1) Separate the organic layer (at pH 6 to 7) along with some impurities from the aqueous Shift off and then proceed as described under 2); "J

2) the entire mixture is coated with ethyl acetate or another suitable organic solvent such as Amyl acetate, butyl acetate, methyl isobutyl ketone, methyl isopropyl ketone or the like, and then gives the inorganic

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Acid, for example hydrogen chloride, until the pH at the temperature of 0 ⁰ C reaches the value 2. The organic layer and the aqueous washing liquids are combined and treated with a suitable drying agent. After the salts have been filtered off and washed with new solvent, the solution of the cephalosporin compound can be treated with an organic alkali metal salt in an organic solvent, a cephalosporin salt being formed which precipitates from the solvent.

The advantages of the present invention reside primarily in the production of cephalotin from impure 7-ACA and impure 2-thienylacetyl chloride. The important thing is that it doesn't it is necessary to use a distilled product to ensure the high yields of the process. It there is great interest in cephalotin as a potent, recognized therapeutic agent.

However, the present invention is not limited to this, as this method is also more effective for synthesizing others Cephalosporin antibiotics can be used by acylating the cephalosporin nucleus of 7-ACA or others cores described in the general formula above can be prepared with various acylating agents.

! The following examples for Cephalosporinprodukte which are halides prepared by acylating the corresponding B-lactam with the corresponding amino acid j Acy, j illustrate the types of compounds which can be obtained according to the methods of the invention: '

7- (phenylacetamido) -cephalosporanic acid, 7- [1- (IHJ-tetrazolylacetamidoJ-cephaolsporanic acid,

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MZU ₁₅ O

j 7- [R- (-) -Formyloxy-pheny! .acetamido] -cephalosporanic acid,

■ 7- [1- (1H) -Tetrazolylacetamidol-3- [t (5-methyl-1,3,4, -thladiazole-

' 2-yl) thio] methyl] -3-cephem-4-carboxylic acid, (cefazolin),

I and

j 7- [R - (-) - Formyloxyphenylacetamido] -3 - [[(1-methyl-1H-tetrazole-

I 5-yl) thio] methyl] -3-cephem-4-carboxylic acid, (Cefamandol nafate)

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example

It became the kinetics of hydrolysis of 2-thienylacetyl chloride in various organic solvents under various experimental conditions in the presence of copious amounts of water : examined.

J The chloride was analyzed by gas chromatography by reacting it with an excess j morpholine.

The amide was injected into the gas chromatograph and its peak area was compared with a standard curve. (Perkin Elmer Model 900 chromatograph equipped with flame ionization detector maintained at 260 C; flow of nitrogen 15 ml / min, column oven temperature 260 ⁰ C, injector at 300 ⁰ C,

2 mm i.d. χ 2.0 m glass columns were made with 2.5% OV-17 j 80-100 mesh Chromosorb G filled).

: For a 1: 1 mixture of water with completely with water j miscible solvent, such as acetone, in the presence of: Sodium hydrogen carbonate as an acid-binding agent is enough Minute off to fully hydrolyze the chloride, while its hydrolysis in the presence of one with water does not miscible organic phase is strictly dependent on the solvent used, that is, on the solubility of water in this solvent.

The following table shows comparative data and preliminary tests upon release of 2-thienylacetyl chloride (10 mmol) in the solvent (10 ml) in the presence of water (10 ml) and Na HCO ₃ (10 mmol) at 0 ° / -5 ⁰ C.

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Tabel solvent

Solubility in% of the water in the solvent

t 1/2 *% hydrolysis after (minutes) 30 minutes

Ethyl acetate 3.3 10 92 Methyl isobutyl ketone 1.6 10 88 benzene 0.06 130 23 toluene 0.05 140 21 Methylene dichloride < 0.1 140 21 * t 1/2 β time after the 50th % of Hydrolyzed chloride is.

Here are just a few examples of the different classes of solvents (esters, ketones, hydrocarbons and halogenated solvents). The acylation reaction is the latter for the three in the table Solvents completely and does not require a large excess of acylating agent (which is relatively expensive).

Example 2 i

27.2 g of 95.5% pure 7-ACA are suspended at 0 ^° C. in 0.5 liters of deionized water and gives 48 ml (96 mmol) 2n sodium hydroxide, taking care that at the addition over 1 1/2 hours at a temperature of.

0 to 5 ⁰ C the pH does not exceed the value 8. I.

24 g of crude 2-thienylacetyl chloride (85% purity) are then added over a period of about 1 1/2 hours, during which process keeps the pH between 6.5 and 7 by adding solid sodium hydrogen carbonate. After stirring for another 30 minutes, the suspension is filtered off and coated with 300 ml of methyl isobutyl ketone. ■

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The pH is brought to 2 ^{at 0 °} C. by adding hydrochloric acid solution; then the organic layer is separated off and the aqueous solution is extracted again twice with 2 × 100 ml of methyl isobutyl ketone. After treatment with activated charcoal and drying with anhydrous sodium sulfate, the salts are filtered off; then cephalotin is precipitated in the form of the sodium salt by adding sodium ethyl hexanoate in methyl isobutyl ketone until a pH of 7.5 to 8 is reached. After stirring for 12 hours at 0 ^° C., the solid is filtered off and washed with a small amount of fresh methyl isobutyl ketone, 34.8 g of sodium cephalotin being obtained (95% purity according to UV analysis).

example

27.2 g of 95.5% pure 7-ACA are suspended in 500 ml of a Buffer solution (pH 7). 0.096 mol of sodium hydroxide is added until complete solution has been achieved (pH 6.8J.

23.2 g of 2-thienylacetyl chloride (92% pure) are dissolved in 20 ml of toluene, the pH being kept constant ^{at 0 ° C. by regular addition of a saturated sodium hydrogen carbonate solution.} The mixture was again stirred for 1 hour, coated with 300 ml of ethyl acetate and then 15% HCl to pH 2 at 0 ⁰ C is reached; separate the layers and dry the organic layer over magnesium sulfate. After filtering off the dry organic solution, a solution which is prepared by dissolving sodium methylate (6 g in 50 ml of methanol) is added until complete precipitation has been achieved.

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! After stirring for 12 hours at ⁰ ° C., the solid obtained is filtered off, washed with ethyl acetate and

dried to obtain 36 g of sodium cephalotin. |

[ ^{α] 2} ^ +128.39 (C = 5, H ₂ O); E] ^% _cm 345 at 237 nm; j

i! Nicotinamide test (E.H. Flynn, "Cephalosporins and Penicillins" j

Academic Press, 1972, p. 679) 94.83%; '

Loss after drying 1.28% with stoichiometric yield! of 85.5%. ^;

example

7-Amino-3 - [[(5-methyl-1,3,4-thiadiazol-2-yl) -thio] -methyl] -3-cephem-4-carboxylic acid (2.064 g, 95.4% purity) suspended
while stirring in a buffer solution (pH 7.8, 50 ml at 20 ⁰ C) by dropwise addition of 10% sodium hydroxide
the solid gradually dissolves until the pH is 8.5
achieved. By adding a 0.1N solution of KH-PO. lowers
the pH is adjusted to 8.1 without the formation of a precipitate. The: temperature of the solution is lowered to 0 - 2 ⁰ C.

1- (1H) -Tetrazolylacetyl chloride (1.97 g) dissolved in 1,2-dichloroethane (30 ml) is added dropwise over 1 hour to the
aforementioned solution whereby one by simultaneous addition of
Sodium hydrogen carbonate (solid or a 5% solution)
maintains the pH near 7.2-7.35. After the addition is complete
the 2-phase solution was stirred again for 1/2 hour. Discard: the organic layer and filter the aqueous solution ^; via decalite to remove the last traces of solvent. By adding 30% hydrochloric acid, it becomes
the pH lowered to 5 - 5.25. The solid obtained (0.46 g)
is filtered off and consists mainly of the starting β-lactam amino acid, which can be reused. j

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M / 18 150 yt

The pH of the solution is then lowered to 1.9 to 2.0 by the dropwise addition of 15% hydrochloric acid. One rührtdie suspension again for 1 1/2 hours at 0 to 2 ⁰ C, filtered! then the white solid and washes with ice-cold water, ι

After dryers in vacuo at 30 ⁰ C is obtained 1.54 g of _pure: cefazolin, 7- [1- (1H) -tetrazolyl-acetamido] -3 - [[(5-methyl- '1,3,4-thiadiazol 2-yl) thio] methyl] -3-cephem-4-carboxylic acid

(90% pure according to HPLC method compared to an FDA j

i standard).

example

1.64 g (5 mmol) of 7-amino-3 - [[(1-methyl-IH-tetrazol-5-yl) -thio] -methyl] -3-cephem-4-carboxylic acid are suspended in 50 ml of a buffer solution (pH 7.8) with stirring and dissolves it by adding 10% sodium hydroxide solution dropwise (pH 7.65).
The pH is lowered to 6.9 by adding 15% HCl,
without solid precipitating.

1/5 g (7.5 mmol) of O-formyl-D - (-) mandeloylchlorid in 4 ml Benzoli is added dropwise over 1 hour at 0 to 5 ⁰ C to that above solution while maintaining the pH by adding 17 ml! Keeps sodium hydrogen carbonate constant at 6.7.

After stirring for 1/2 hour, a little ethyl acetate is added to allow the organic layer to separate easily
can; then you coat the aqueous solution with fresh! Ethyl acetate and lowers the pH by adding chlorinated water! chemical acid (at 0 ⁰ C) to 2.

After stirring for 10 minutes, the organic layer is separated off and the aqueous solution is extracted again with
fresh ethyl acetate. After drying with anhydrous sodium

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sulfate, the organic phase is evaporated in vacuo, the semi-solid residue is dissolved in 30 ml of ethanol and mixed with something Treated activated carbon. After filtering off, a solution is added

of 760 mg of sodium acetate trihydrate in 4 ml of methanol. After stirring for 12 hours at 0 C, the white solid is filtered off, washed with ethanol, 0.9 g of cefamandol-nafate being obtained after drying in vacuo (35%).

204.1 at 271 nm. NMR shows impurities of

Cefamandol in the order of 12%.

7 '

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Claims (1)

Claims Process for the production of cephalosporin derivatives such as cephalotin, cefazolin, cefamandol-nafate, 7- (phenylacetamido) -cephalosporanic acid, 7-11- (1H) tetrazolylacetamido] -cephalosporanic acid and 7- [R - (-) - Formyloxy-phenylacetamido] -cephalosporanic acid by acylating 7-aminocephalosporanic acid and its derivatives of the general formula (I), (D COOH where X is or -OCOCH. stands, with crude or distilled acyl halides, characterized in that the 7-ACA and its derivatives of the formula (I) are dissolved in water at a mild temperature (0 to 30 ^° C.) and the suitable acyl halide dissolved in one with Haters immiscible organic solvents, admits. ORIGINAL INSPECTED Process according to Claim 1, characterized in that the 7-ACA and its derivatives of the formula (I) Dissolve in water or in a buffered solution of pH 7, at least the stoichiometric amount inorganic or organic bases such as sodium or potassium hydroxide or aliphatic tertiary amines are used, keeping the final pH between 6 and 8.5. Method according to one of the preceding claims, characterized in that the organic solvents, in which the appropriate acyl halide is dissolved are water immiscible solvents (Water solubility less than 0.1%). 4. The method according to any one of the preceding claims, characterized in that the acylation at a temperature between 0 ⁰ C and 35 ⁰ C, preferably between 0 ⁰ C and 5 ⁰ C is carried out. 5. The method according to any one of the preceding claims, characterized in that the pH range during j the acylation by adding mild alkaline bases,! like sodium hydrogen carbonate, constant at values \ from 6 to 8 is held. | 709882 / 1063-