IE43509B1 - Acylated 6 amino-2,2-dimethyl-3-(5-tetrazolyl) penams and a process for their production - Google Patents

Description

This invention relates to antibacterial agents and it is particularly concerned with certain acylated derivatives of 6-amino-2,2-dimethy1-3-(5-tetrazolyl)penam and with methods for their preparation.

In Patent Specification No. 40532. there are described and claimed novel antibacterial agents of the Formula I: wherein R^ is an acyl group of an organic carboxylic acid.

According to the present invention which is an improvement or modification of the invention the subject of the said prior application there are further provided compounds of the Formula II: -243809 and the pharmaceutically acceptable salts thereof; wherein z1 is wherein Z2 is selected from hydrogen, alkanoyi having from 2 to 4 carbons or alkylsulfonyl having from 1 to 3 carbon atoms.

The said compounds of the Formula II, which are not specifically disclosed in said prior application, show especially valuable antibacterial properties, and in particular they possess important advantages over the structurally most-closely related analogues disclosed in said prior application.

The compounds of the present invention can be named as derivatives of penam”, which has been defined by Sheehan et al. in the Journal of the American Chemical Society, 75, 3293 (1953), as referring to the structure i Ί 3 Although the term penam does not normally carry any steroechemical implications, the absolute stereochemistries (absolute configurations) of the compounds of this invention at positions 3, 5 and 6 correspond to those found in the penicillins normally obtained by fermentation. Additionally, in the compounds / chis invention, the asymnetrically substituted carbon atom in the side-chain attached to C-6 of the penam nucleus is in the (R)-configuration. By analogy with nomenclature used in peptide chemistry, -3and in line with common practive in naming penam compounds, this is also designated as the ^-configuration.

The compounds of the present invention are 5substituted tetrazole compounds, and such compounds can exist in two forms, viz: As will be appreciated by one skilled in the art, in a given compound these two forms co-exist in a dynamic, tautomeric, equilibrium mixture. For the sake of simplicity in this specification, the compounds Of the invention will be shown only in the form wherein the hydrogen atom is at the 1-position of the tetrazole ring? however, it is to be understood that this invention embraces the compounds wherein the hydrogen atom is at the 1-position of the tetrazole ring, the compounds wherein the hydrogen atom is at the 2-position of the tetrazole ring, and mixtures thereof.

It should also be noted that the 4-hydroxy-l,5naphthyridine grouping is a tautomeric system, which can be dipicted, and named, as a 1,4-dihydro-4-oxo-l,5-naphthyridine ) group.

Typical compounds according to the invention ν include those rn which Z is acetyl, propionyl, butonyl, methyl sulfonyl, ethyl sulfonyl and propyl sulfonyl.

From a second aspect the present invention i provides a process for the production of a compound of the formula -443508 wherein z1 ia wherein Z2 is selected from hydrogen, alkanoyl having from two to four carbon atoms or alkylsulfonyl having from one to three carbon atoms, or a pharmaceuticaliyacceptable salt thereof, which comprises acylation of an amine of the formula H— L OH NH-CH-CO -5or a tetrazolyl protected derivative thereof, with an activated derivative of a carboxylic acid of the formula wherein n is 1 or 0 and if required removing the tetrazolyl 5 protecting group, and if desired, converting the product into a pharmaceuticaliy-acceptable salt.

As will be appreciated by those skilled in the art compounds of the formula •N w and wherein n is 1 or 0 respectively can themselves be prepared by an acylation reaction. If such a preparation is employed -643509 the final preparation of the antibiotic compounds of the invention can be effected with or without isolation of the intermediate.

In one method according to the invention, the 5 compounds of the Formula II are prepared by acylation of 6-(D-2-amino-2-[4-hydroxyphenyl]-acetamido)-2,2-dimethyl3-(5-tetrazolyl)penam, the compound of the Formula III, with an activated derivative of the appropriate carboxylic acid of the Formula IV: .(III) . (IV) As will be appreciated by one skilled in the art, the carboxylic acids of the Formula IV, wherein Z1 is I2 are difficult to isolate, since they tend to decarboxylate spontaneously.. However, various activated derivatives thereof are readily obtainable by standard procedures.

The acylation is carried out by contacting the compound or the Formula III, or a salt thereof, with the -720 Δ3809 activated derivative of the carboxylic acid IV, in an appropriate solvent system.

An activated derivative commonly used i3 an acid halide, such as an acid chloride. In a typical acylation procedure, approximately one molar equivalent of the acid chloride is added to a solution of the said compound, of Formula III, or a salt thereof, dissolved in a solvent such as a chlorinated hydrocarbon, for example, chloroform or methylene chloride; an ether, for example, tetrahydrofuran or 1,2-dimethoxyethane; an ester, for example, ethyl LO acetate or hutyl acetate; a lower aliphatic ketone, for example acetone or methyl ethyl ketone; or a tertiary amide, for example, Ν,Ν-dimethylformamide or N-methylpyrrolidone; at a temperature in the range from -4·Οθβ. to 30θ0., and preferably from —10°C. to 10°C., optionally in the presence .5 of about one molar equivalent of an acid-binder, e.g., triethylamine, pyridine or sodium bicarbonate. The reaction is complete within a short period, i.e., approximately one hour.

An alternate procedure useful for the acylation of a compound of Formula III with acid halides involves the use of an aqueous solvent system. In this procedure, which is the Schotten-Baumann procedure, the acid halide is added to a solution of the starting material in water, or a mixture of water and another inert solvent, at, or slightly below- ambient temperature, with the pH of the solvent being maintained within the range from-6.0 to 9.0 before, during, and after the addition.

Other activated derivatives of the carboxylic acids of the Formula IV which can be used are active esters. Active esters which can be used in this regard are, for ex) ample, phenyl esters, such as p-nitrophenyl and 2,4,5-tri-843509 chlorophenyi esters; thio esters, such as thiol phenyl and thiol methyl esters; and N-hydroxy esters, such as N-hydroxysuccinimide and N-hydroxyphthalimide esters. The esters are prepared by methods well established in the art, and the acylation is conveniently conducted by dissolving the active ester and the said compound of Formula III, or a salt thereof, in a dipolar aprotic solvent such as N,N-dimethylformamide, Ν,Ν-dimethylacetamide or N-methylpyrrolidone. The solution is stored at about ambient temperature for several hours, for example overnight, and then the product is isolated by standard methods. In many cases the active ester used in this process can be replaced by the corresponding acid azide or by the imidazole or triazole amide.

An activated derivative of the carboxylic acid of the Formula IV which can be used in the specific case wherein zl is is a mixed anhydride. Typically, a carboxylate salt of 4-hydroxy-l,5-naphthyridine-3-carboxylic acid is treated with about one molar equivalent of a lower-alkyl chloroformate in a reaction-inert, aprotic, organic solvent, at a temperature in the range from -20°C. to 20°C. and preferably at aoout 0°C. Appropriate salts for this process are alkali metal salts, such as sodium and potassium salts, and tertiary amine salts, such as triethylamine, tributylamine, N-ethylpiperidine, Ν,Ν-dimethylaniline, N-methylmorpholine -948S09 and pyridine salts; and appropriate solvents are, for example chloroform, methylene chloride, acetonitrile, tetrahydrofuran dioxane and Ν,Ν-dimethylformamide. The mixed carboxyliccarbonic anhydride thus formed is usually used in situ to acylate the said compound of Formula III. This is normally carried out by mixing solutions of the preformed mixed anhydride and the compound of Formula III. The acylation is normally conducted at a temperature in the range from about -30°C. to about 20“C., and preferably at about -10°C., and it usually takes a £ew hours to reach completion. In most instances the mixed anhydride and the compound of Formula III are contacted substantially in a 1:1 molar ratio» A further alternate method which can be used to acylate a compound of the Formula III with 4-hydroxy-l,515 naphthyridine-3-carboxylic acid comprises contacting the said compound of the Formula III with 4-hydroxy-l,5-naphthyri· dine-3-carboxylic acid in the presence of certain agents known in the art for forming peptide bonds. Such agents include carbodiimides, for example, dicyclohexylcarbodiimide and l-ethyl-3-(3-dimethylaminopropyl)carbodiimide, alkoxyacetylenes, for example methoxyacetylene and ethoxyacetylene, and N-ethoxycarbonyl-2-ethoxy-l,2-dihydroquinoline. The reaction is carried out in an appropriate solvent, i.e. one which will serve to dissolve the reactants, and does not adversely interact with the starting materials or the product, for example acetonitrile, Ν,Ν-dimethylformamide and N-methylpyrrolidone.

In a second method according to the invention, the compounds of the Formula II are prepared by acylation of 6-amino-2,2-dimethylr-3-(5-tetrazolyl)penam, the compound -104U&Us> of the Formula V, with an activated derivative of the appropriate carboxylic acid of the Formula VI. wherein Z^· is as defined previously. The acid of the Formula VI is activated by any of the methods described hereinbefore for activation of 4-hydroxy-l,5-naphthyridine-3-carboxylic acid, and the acylation is conducted by any of the methods described hereinbefore for the acylation of the compound of the Formula III with an activated derivative of 4-hydroxy-1,5naphthyridine-3-earboxylic acid. The acids of the Formula VI are prepared by acylation of 2-amino-2-[4-hydroxyphenyl)acetic acid with an activated derivative of an acid of the formula Z1-COOH.

It should be noted that in a process for the acylation of a compound of the Formula HI or V, hydrogen atoms on the tetrazole ring, hydrogen atoms on the primary amino functions, and the hydrogen atom of the phenolic hyd-:oxv group in the compound of the Formula III can be replaced oy triaikylsilyl groups. Said trialkylsilyl groups are chen removed, and replaced by hydrogen at the end of the -1143509 acylation, simply by brief exposure of the product to a protic solvent system, such as water or a loweralkanol, for example, methanol or ethanol. By virtue of the ready availability of the starting materials, the trimethylsilyl group is a preferred member. It can be introduced into the starting penam of Formula III or V by methods well known in the art, such as, for example, using trimethylchlorosilane or N-trimethylsilylacetamide, as discussed by Birkofer and Ritter in Angewandte Chemie (International Edition in English), £, 417-418 and 426 (1965). Conditions must be chosen, however, which are compatible with the β-lactam group of the penam nucleus. Also, operative in this regard are the silylated derivatives formed by interaction of the said compounds of Formulae III or V with dichlorodi-(lower-alkyl)silanes. The silylation step is carried out by methods known in the art (for example, German Patent No. 1,933,187). After the acylation reaction, the silyl group is removed by treatment with a protic solvent, such as water or a lower-alkanol, for example, methanol or ethanol.

Additionally, if desired, the tetrazole ring of a compound of Formula III or V can be protected by various other groups prior to acylation. The protecting group is then removed, after acylation, to liberate the desired antibacterial agent of Formula II. A wide variety of protecting groups can be used for this purpose, such as, for example, triphenyImethyl, substituted triphenyImethyl, alkoxymethyl, benzyloxymethyl, substituted benzyloxymethyl, cyanomethyl, benzyl, substituted benzyl, alkoxycarbonyl, phenoxycarbonyl and substituted phenoxycarbonyl.

The starting materials of the Formula III and V -12' are prepared by the methods taught in the said application. 4-Hydroxy-l,5-naphthyridine~3-carboxylic acid is prepared by the method of Adams et al., Journal of the American Chemical Society, 68, 1317 (1946).

By virtue of the fact that the carboxylic acids of the Formula IV, wherein Z^· is I2 tend to decarboxylate, activated derivatives thereof are usually prepared directly from a oompound of the Formula VII: H ir ... (vid For example the compounds of the Formula VII can be reacted with phosgene, or phenyl or a substituted phenyl chloroformate. Preparation of the compounds of Formula VII, wherein 22 is as previously defined, and their subsequent reaction with phosgene to acid chlorides, is described in Patent Specification Βίο, ι 37123.

By virtue of the acidic nature of 5-monosubstituted tetrazole compounds, the compounds of this invention of the Formula II form salts with basic agents, and all such salts are to be considered within the scope of this invention Salts which are of particular value are alkali metal salts, alkaline earth metal salts, as well as salts formed from organic amines. Especially valuable salts are the sodium 134350© and potassium salts.

The salts of the compounds of the Formula II are prepared by standard techniques, such as contacting the acidic and basic components, usually in a lsl molar ratio, in an aqueous, non-aqueous or partially aqueous medium, as appropriate. They are then recovered by filtration, by precipitation followed by filtration, by evaporation of the solvent, or, in the case of aqueous solutions, by lyophilization, as appropriate. Basic agents which are suitably employed in salt formation include ammonia, organic amines, alkali metal hydroxides, carbonates, bicarbonates, hydrides and alkoxides, as well as alkaline earth metal hydroxides, carbonates, hydrides and alkoxides. Representative examples of such bases are primary amines, such as n-propylamine, n-butylamine, aniline, cyclohexylamine, benzylamine, j>-toluidine and octyl-aminej secondary amines, such as diethylamine, N-methylaniline, morpholine, pyrrolidine and piperidine? tertiary amines, such as triethylamine, Ν,Ν-dimethylaniline, 'N-etbylpiperidine, N-methylmorpholine and l,5-diazabicyclot4.3.0]non-5-ene? hydroxides, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide and barium hydroxide; alkoxides, such as sodium ethoxide and potassium ethoxide? hydrides, such as calcium hydride and sodium hydride; carbonates, such as potassium carbonate and sodium carbonate; and bicarbonates, such as sodium bicarbonate and potassium bicarbonate.

The compounds of the Formula II and the salts thereof show outstanding and unexpected antibacterial activity in vitro against a wide variety of gram-positive and gramnegative organisms. This in vitro activity can be demonstrated -1443509 using the conventional two-fold serial dilution technique.

In practice, agar plates having the test compound incorporated therein at the various concentrations are inoculated with a standard number of the appropriate organism. The plates are incubated for 18 hours at 37°C-, and then each plate is observed visually for the presence or absence of growth of bacteria. The minimum inhibitory concentration (MIC), which is the lowest concentration of test compound which prevents growth of the microorganism in question, is then noted.

Microorganisms against which the compound of the Formula II and their salts show activity are, for example, strains of Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Klebsiella pneumoniae, Proteus morgani, Proteus mirabilis, Pseudomonas aeruginosa, Serratla marcescens and Salmonella typhimurium.

Comparative data of MIC's determined as described above for compounds according to the invention and similar compounds falling outside the scope of the invention are set out below,all of the compounds are of the general formula: -150509 co Γ* ο KO in in in Ci cd ca rH •H rH β Φ Q rH ♦H s 6 CQ 3 \ Z3 φ tr V a 0 rH cu 3 tt 0 U) rj H β β S Φ rd -P tr 0 H M 0 0« g rH cn in OJ t KO in OJ in OJ KO KO in rH in OJ i KO cd fH H rH $H Φ g β g o H g Λ rH α cd >1 ω •Pl CQ β cd Φ •H υ 4J to cd Φ M 0 M M Φ cd ω g eo o© oi rd cn in oi KO ι-1 cn © in in oi m ko oj rH in OJ rH in OJ [-SO2-CH3 12.5 1.56 1.56 3.12 3.12 12.

W KO W ΡΙ g 01 Φ π} W β 0 0 β a •rd 0 CJ1 »0 β β Η φ φ <0 φ Οι Φ φ r4 Ή Η rd β Ε Φ 0 X •Η § tr η Ρ 0 Λ Φ e Φ β rd 24 α Η •Η a η α β π) φ σ> Ρ Μ 0 Ο Μ Ε fit Φ § rd •Η rd Μ Φ 3 β Ε 0 •rd β 49 rd α Φ W Ρι Φ (0 β φ •rl ϋ Ρ (0 φ φ Μ ϋ Μ Μ Φ φ ω ε chia *Η •Η rd Ρ Φ 0 ϋ Λ ϋ ω W ο Οί 4350 activity of the comthereof makes them for example in water The in vitro antibacterial pounds of the Formula II and the salts valuable as industrial antimicrobials, treatment, slime control, paint preservation and wood preservation, as well as for topical application as disinfectants. In the case of use of these compounds for topical application it is often convenient to admix the active ingredient with a non-toxiq carrier, such as vegetable or mineral oil or an emollient cream. Similarly, it can be dissolved or dispersed in liquid diluents or solvents such as water, alkanols, glycols or mixtures thereof. In most instances it is appropriate to employ concentrations of active ingredients of from about 0.1 per cent to about 10 per cent by weight, based on total composition.

Additionally, the compounds of the Formula II, and the pharmaceutically-acceptable (i.e. non-toxic) salts thereof, show outstanding and unexpected antibacterial activity in vivo. In determining such activity, the test compound is administered to mice which have been infected by intraperitoneal injection of a lethal inoculum of pathogenic bacteria. The test compound is administered using a multiple dosing regimen, using the subcutaneous (SC) route. The inoculum of bacteria varies from one to about ten times the amount needed to kill 100% of the mice, under the conditions of the test. At the end of the test, the activity of a compound is assessed by counting the number of survivors among the treated animals, and expressing the activity of a compound as the percentage of animals which survive. The compounds of the Formula II and their pharmaceutically-acceptable salts show valuable in -1843509 vivo antibacterial activity against, l'er example. strains of Staphylococcus aureus. Escherichia coli. Klebsiella pneumoniae and Pseudomonas aeruginosa.

The in vivo antibacterial activity of the compounds of the Formuls II and the pharmaceutically-acceptable salts thereof makes them suitable for the control of bacterial infections in mammals, including man, particularly by the parenteral route of administration. The compound of the Formula IX and the pharmaceutically-acceptable salts thereof will find wide use in the control of infections caused by susceptible gram-positive and gram-negative bacteria in human subjects.

When considering therapeutic use of a compound of the Formula IX, or a salt thereof, in a mammal, particularly man, the compound can be administered alone, or it can be mixed with other antibiotic substances an/or pharmaceutically-acceptable inert carriers, diluents, solvents or fillers in accordance with standard pharmaceutical practice. Thus, for parenteral administration, which includes intramuscular, intraperitoneal, subcutaneous and intravenous use, sterile solutions of the active ingredient are usually prepared, and the pH of the solutions are suitable adjusted and buffered. For intravenous use, the total concentration of solutes should be controlled to render the preparation isotonic.

When a compound of the present invention is used in man, the daily dosage to be used will not differ significantly from other, clinically-used, penam antibiotics. The proscribing physician will ultimately determine the appropriate dose for a given human subject, and this can be expected to vary according to the age, weight, and response - 19 of the individual patient, as well as the nature and the severity of the patient's symptoms. However, the compounds of this invention will normally be used parenterally at dosages from about 10 to about 400 mg. per kilogram of body weight per day. These figures are illustrative only, however, and in some cases it may be necessary to use dosages outside these limits.

The following examples are provided solely for the purpose of further illustration.

EXAMPLE I 6-(D-2-[4-Hydroxy-1,5-naphthyridine-3-carboxamido J -2-[4-hydroxyphenyl]acetamido)-2,2-dimethyl-3-(5tetraaolyl) penam To a solution of 4.20 ml (0.030 mol) of triethylamine in 50 ml. of hexamethylphosphoramide is added 2.85 g. (0.015 mol) of 4-hydroxy-l,5-naphthyridine-3-carboxylic acid. The mixture is stirred for 15 minutes at 25°C., and then 5 drops of N-methylmorpholine are added. The solution is cooled to ca. 0°C. and 1.44 ml. (0.030 mol) of ethyl chloroformate is added. The mixture is stirred for 10 minutes at 0-5°C., and then an additional 1.44 ml. of ethyl chloroformate is added and stirring is continued for another 10 minutes. To the solution of the mixed anhydride thus obtained, is added a solution prepared from 6.65 g. (0.015 mol) of 6-(D“2-amino-2[4-hydroxyphenyl]-acetamido)-2,2-dimethy 1-3-(5-tet.razolyl)penam trihydrate, 2.10 ml. (0.015 mol) of triethylamine and 50 ml. of hexamethylphosphoramide, at 0-5°C. The resulting mixture is stirred for 35 minutes while it is allowed to warm slowly to 25°C. At this point the reaction mixture is diluted with 1,000 ml. of water and then filtered through a pad of celite (Registered Trade Mark) (a diatomaceous silica product). The filtrate is added to a further 1,000 ml of water, with the pH of the water being maintained at 2.5 during the addition by the addition of 6N hydrochloric acid. This causes a solid to precipitate. After stirring the mixture at ca 0°C for 15 minutes, the precipitate is removed by filtration under nitrogen. The resulting solid is washed with water, followed by ether, and then dried, giving 3.7 g. of the title compound. The product is purified further by trituration with acetone and drying. The final yield is 3.6 g. (43% yield).

EXAMPLE II 6-(D-2-[4-Hydroxy-l,5-naphthyridine-3-carboxamido]2- [ 4-hydroxyphenyl]acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam Sodium Salt A suspension of 6.0 g. of 6-(D-2-[4-hydroxy-l,5naphthyridine-3-carboxamido]-2-[4-hydroxyphenyl]acetamido)2,2-dimethyl-3-(5-tetrazolyl)penam in 450 ml of water is stirred at 25*C., and IN sodium hydroxide is added slowly until a constant pH of 7.0 is obtained. The small amount of insoluble material is removed by filtration, and the filtrate is lyophilized to give the title sodium salt (6.6 g). The infrared spectrum of the product (KBr disc) shows absorption bands at 3400, 1770, 1655, 1575, 1550, 1540, 1520, 1470, 1430, 1380, 1330, 1250 and 1210 cm1. The nuclear magnetic resonance spectrum (in a mixture of D2O and (CD3)2SO) shews ausorption bands at 9.15-8.8 (multiplet, 2H), 8.5-8.1 (multiplet, IH), 8.1-7.7 (multiplet, IH), 7.45 (doublet, 2H), 6.85 (doublet, IH), 6.1-5.8 (multiplet, IH), .8-5.4 (multiplet, 2H), 5.2 (singlet, IH), 1.6 (singlet, IH), and 1.0 (singlet, IH), the absorption bands being expressed in parts per million downfield from internal tetramethylsilane. -214350® EXAMPLE III 6(D-2-[4-Hydroxy-l,5-naphthyridine-3-carboxamido]2-[4-hydroxyphenyl]acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam Potassium Salt The procedure of Example II is repeated, except that the IN sodium hydroxide solution used therein is replaced by IN potassium hydroxide. This affords the potassium salt of 6-(D-2-[4-hydroxy-l,5-naphthyridine-3-carboxaraido2-[4-hydroxyphenyl]acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam.

EXAMPLE IV 6- (D-2- [3-&cetylimidazolidin—2-one-l-carboxamido] 2-[4-hydroxyphenyl]-acetamido)-2,2-dimethy1-3-(5-tetrazolyl)penam .

To a solution of 3.54 g. of 6-(D-2-amino-2-[4hydroxyphenyl]-acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam trihydrate in 100 ml. of tetrahydrofuran-water (25:75), at 0’C., is added, with stirring, triethylamine until the pH is 8.0. To this solution is then added, in portions, during 30 minutes, 1.78 g. of 3-acetylimidazolidin-2-one-l-carbonyl chloride, with the pH being maintained at 8.0 by the addition of triethylamine. The reaction mixture is stirred for 15 minutes at pH 7.5 after the addition of the acid chloride, and then 200 ml. of water are added. The bulk of the tetrahydrofuran is removed by evaporation in vacuo, and then the pH of the residual aqueous solution is adjusted to 3.8, using 6N hydrochloric acid. After 15 minutes the solid which has precipitated is collected by filtration and dried. This affords 3.5 g. of crude product. The crude product is suspended in water and the pH is raised to 8.0 using 2N sodium hydroxide. The mixture is stirred for 15 minutes and then filtered. The pH of the filtrate is adjusted to 3.8, and -22«aaoe the solid is recovered by filtration. This affords 2.3 g (53% yield) of the title compound. The nuclear magnetic resonance spectrum (in (CD^^SO solution) shows absorption bands at 9.3 (multiplet, IH), 8.9 (doublet, IH), 7.3 (doublet, 2H), 6.8 (doublet, 2H), 5.8-5.2 (multiplet, 5H + impurity), 3.7 (singlet, 4H), 2.4 (singlet, 3H), 1.6 (singlet, 3H) and 1.0 ppm (singlet, 3H), downfield from internal tetramethylsilane. The infrared spectrum of the product (in mineral oil) shows strong absorption bands at 1780, 1730 and 1660 cm.-1.

EXAMPLE V 6-(D-2-[3-MethylBulfonyllmidazolidin-2-one-lcarboxamido]-2-[4-hydroxyphenyl]acetamido)-2,2~dimethyl-3(5-tetrazolyl)penam The title compound is prepared in 67% yield by acylation of 6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)-2,2dimethy1-3-(5-tetrazolyl)penam trihydrate with 3-methylsulfonylimidazolidin-2-one-l-carbonyl chloride, using the procedure of Example IV. The infrared spectrum of the product (in mineral oil) shows strong absorption bands at 1780, 1730, 1660 and 1160 cm.-1. The nuclear magnetic resonance spectrum (in (CDjJjSO solution) shows absorption bands at 9.0 (multiplet), 8.2 (multiplet), 7.6 (doublet), 7.3 (doublet), 6.8 (doublet), 5.7 (multiplet), 3.9 (singlet), 3.4 (singlet), 1.6 (singlet) and 1.0 ppm (singlet), downfield from internal tetramethylsilane.

EXAMPLE VI 6-(D-2-[Imldazolidln-2-one-l-carboxamido]-2- [4hydroxyphenyl]-acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam The title compound is prepared in almost guanti-23tative yield by the acylation of 6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam trihydrate using imidazolidin-2-one-l-carbonyl chloride. The procedure used is the procedure of Example IV, except that 2N sodium hydroxide is used in place of the triethyiamine.

The infrared spectrum of the product (in mineral oil) shows strong absorption bands at 1760, 1730, 1680 and 1660 cm._d.

The nuclear magnetic resonance spectrum (in D2O/(CD3)2SO) shows absorption bands at 7.4 (doublet, 3H), 6.8 (doublet, 2H), 5.7 (broad singlet, 3H), 5.3 (singlet, IH), 3.8 (broad singlet, 2H), 3.5 (broad singlet, 2H), 1.7 (singlet, 3H) and 1.1 (singlet, 3H)ppm, downfield from internal tetramethylsilane.

PREPARATION 4-Hydroxy-l,5-naphthyridine-3-carboxylie Acid A. Diethyl-2-([3-pyridylamino]methylene)malonate A mixture of 23.5 g. (0.25 mol.) of 3-aminopyridine and 54 g. (0.25 mol.) of diethyl 2-(ethoxymethylene)malonate is heated with stirring for 1 hour at 155°C. The mixture is cooled to 25eC., whereupon it solidifies. The solid is broken up using a pestle, giving 64.5 g. (98% yield) of diethyl 2-([3-pyridylamino]methylene)malonate. Β» Ethyl 4-hydroxy-l,5-naphthyridine-3-carboxylate A mixture of 265 g. of diphenyl and 735 g. of diphenyl ether is heated to 255°C., and then the above diethyl 2-((3-pyridylamino]methylene)malonate is added all at once. The temperature of the mixture is maintained at 255°C. until ethanol is no longer evolved. The mixture is -24cooled to 25’C. and the precipitate is removed by filtration. It is washed liberally with hexane and dried. This affords 40.5 g. (75% yield) of ethyl 4-hydroxy-l,5-naphthyridine-3carboxylate.

C. 4-Hydroxy-l,5-naphthyridine-3-carboxylic acid To a solution of 8.0 g. (0.2 mol.) of sodium hydroxide in 200 ml. of water is added 20.0 g. (0.0917 mol.) of ethyl 4-hydroxy-l,5-naphthyridine-3-carboxylate. The mixture is heated under reflux for 6 hours, and then the hot solution is treated with decolorizing charcoal and then filter ed hot. The filtrate is cooled to 25’C. and acidified to pH 3 with 6N hydrochloric acid. The mixture is then cooled in an ice-bath for 15 minutes and the precipitate is removed by filtration. The solid obtained is washed with water, followed by ether, followed by acetone, and dried. This affords 11.2 g (64% yield) of 4-hydroxy-l,5-naphthyridine-3carboxylic acid.

Claims (18)

CLAIMS:1. A compound of the formula or alkyl sulfonyl having from 1 to 3 carbon atoms.

1. ,5-naphthyridine-3-carboxamido]-2-[4-hydroxyphenyl]acetamido) 2 r 2-dimethyl-3-(5-tetrazolyl) penam and pharmaceutically acceptable salts thereof.

2. A compound according to claim 1, 6-(D-2-[4-hydroxy·

3. A compound according to claim 1, 6-(D-2-[3acetylimida2olidin-2-one-l-carboxamido]-2-[4-hydroxyphenyl]aoet amido)-2,2-dimethyl-3-(5-tetrazolyl)penam and pharmaceutically acceptable salts thereof.

4. A compound according to claim 1, 6-(D-2-[3-methylsulfonyl-imidazolidin-2-one-l-oarboxamido]-2-[4-hydroxyphenyl] · - 26 «3509 acetamido)-2,2-dimethyl-3-(5-tetrazolyl)penam and pharmaceutically acceptable salts thereof. 5. Effected in a dipolar aprotic solvent. 5 wherein n is 1 or 0 and if required removing the tetrazolyl protecting group, and if desired, converting the product into a pharmaceutically-acceptable salt.

5. A compound according to claim 1, 6- (D-2- [imidazolidin-2-one-l-carboxamido]-2-[4-hydroxyphenyl]-acetamido)-2,25 dimethyl-3-(5-tetrazolyl)penam.

6. A process for the production of a compound of the formula alkanoyl having from two to four carbon atoms or alkylsulfonyl having rrom one to three carbon atoms, or a pharmaceutically-acceptable salt thereof, which comprises acylation of an amine of the formula 43600 or a tetrazolyl protected derivative thereof, with an activated derivative of a carboxylic acid of the formula

7. A process according to claim 6, wherein said activated derivative of a carboxylic acid is an acid halide.

8. .08. A process according to claim 7, wherein said reaction is carried out in an organic solvent at a temperature of from -10 to 10°C.

9. A process according to claim 8, wherein said process is carried out in the presence of an acid-binder. 5

10. A process according to claim 7, wherein said amine is dissolved in an aqueous solvent and acid chloride added 43S09 thereto whilst the pH is maintained in the range 6.0 to 9.0.

11. A process according to claim 6, wherein ««id activated derivative of a carboxylic acid is a phenyl eater, a thio ester, or an N-hydroxy ester and said acylation is

12. A process according to claim 6, wherein said acid is wherein Z is as defined m claim 6, and n is 0 wherein said activated derivative is a mixed anhydride.

13. A process according to claim 12, wherein said mixod anhydride is formed with a lower alkyl ester of chloroformic acid.

14. A process according to claim 13s which is effected at a temperature in the range of -20 to +20θ0.

15. A process according to claim 6, wherein said acid is 29 <53308 wherein Z d is as defined in claim 6, and n is 0 and said acylation is carried out in the presence of a peptide forming agent. 43508

16. A process for the production of a compound as claimed in claim 1, substantially as hereinbefore described in any of the Examples.

17. A pharmaceutical composition comprising a com5 pound as claimed in claim 1 and a pharmaceutically acceptable inert diluent, carrier, solvent or filler.

18. A compound according to claim 1, whenever obtained by the process of any of claims 6 to 16.