Semisynthetic beta-lactam antibiotics. II. Synthesis and antibacterial activity of 7beta-[2-(acylamino)-2- (2-aminothiazol-4-yl)acetamido]cephalosporins

Cephalosporin derivatives (I) substituted with a neutral, acidic or basic amino acid group as the terminal group attached to the 2-amino-2-(2-aminothiazol-4-yl)acetamido side chain at the C-7 position were synthesized, and the effect of each group on antibacterial activity was examined. The derivatives bearing an amidino or guanidino group showed broad spectra of antibacterial activity similar to those of cefotaxime, but they were relatively sensitive to beta-lactamases.     

Semisynthetic beta-lactam antibiotics. III. Synthesis and antibacterial activity of 7 beta-[2-(2-aminothiazol-4-yl)-2-(substituted carbamoylmethoxyimino)acetamido]cephalosporins

Syntheses of cephalosporins modified with a 7 beta-[2-(2-aminothiazol-4-yl)-2-(substituted carbamoylmethoxyimino)acetamido] group at the C-7 position and with various hetero aromatics at the C-3 position are described. The effects of substituents on the carbamoyl group in the 7-side chain were investigated in order to improve antibacterial activity. Some of these compounds exhibited high antibacterial activity against Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa, as well as good resistance to beta-lactamase.     

Studies on cephalosporin antibiotics. I. Synthesis, antibacterial activity and oral absorption of new 3-(O-substituted)-7 beta-[D-alpha-amino-alpha-(4-hydroxyphenyl)acetamido]cephalosporins

The synthesis, antibacterial activity and oral absorption of new 7 beta-[D-alpha-amino-alpha-(4-hydroxyphenyl)acetamido]cephalosporins (1) with various O-substituents at the C-3 position of a cephalosporin nucleus are described. Of these, the cephalosporins (1b-1e) having an alkoxycarbonylmethoxy group at the C-3 position showed good oral absorption in rats as well as potent activity against Gram-positive bacteria. The structure-activity relationships of 1 are also presented.     

Synthesis and structure-activity relationships of 7 beta-[2-(2-aminothiazol-4-yl)acetamido]cephalosporin derivatives. V. Synthesis and antibacterial activity of 7 beta-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-cephalosporin derivates and related compounds

In order to improve the antibacterial activity of 7 beta-[2-(2-aminothiazol-4-yl)acetamido]-cephalosporins new derivatives having a methoxyimino moiety in the 7-acyl side chain and related compounds were synthesized. Of these, 7 beta-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamido]-cephalosporins were found to possess excellent activity against a variety of Gram-positive and Gram-negative bacteria including beta-lactamase-producing strains. An extensive study of structure-activity relationships led to the selection of 7 beta-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamido]-3-[(1-methyl-1H-tetrazol-5-yl) thiomethyl]-ceph-3-em-4-carboxylic acid, SCE-1365, for further biological and clinical evaluation.     

Studies on beta-lactam antibiotics. X. Synthesis and structure-activity relationships of 7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-(carboxymethoxyimino)acetamido] cephalosporin derivatives

The synthesis of 7 beta-([Z) -2-(2-amino-4-thiazolyl)-2-(carboxymethoxyimino) acetamido]-cephalosporins (2a-h) modified at the C-3 position of a cephem nucleus and the effect of the C-3 substituents on the antibacterial activity, oral absorptivity and therapeutic activity are discussed. The cephems (2a and 2b) having a C-3 substituent such as hydrogen or vinyl were more potent than other cephalosporins against Gram-negative bacteria. However, the cephalosporin (2f) having methylthio group at the 3-position showed the highest absorption rate in rats. These three cephalosporins (2a, b and f) exhibited equally good protective activities in mice infected. Furthermore, the serum levels of these cephalosporins (2a, b and f) were examined in dogs, and 2b and 2f showed outstanding high and prolonged serum levels.     

Semisynthetic beta-lactam antibiotics. I. Synthesis and antibacterial activity of new ureidopenicillin derivatives having catechol moieties

The synthesis and antibacterial activity of new ureidopenicillin derivatives having catechol moieties in the 6-acyl side chain are described. These compounds showed remarkably strong activities against Pseudomonas aeruginosa. Especially, 6-[(R)-2-[3-(3,4-dihydroxybenzoyl)-3-methyl-1-ureido]-2- phenylacetamido]penicillanic acid (7a) had the most potent activity in vitro against Gram-negative bacteria, its activity being 30 approximately 60-fold greater than that of piperacillin against most strains of P. aeruginosa.     

Studies on beta-lactam antibiotics. XIII. Synthesis and structure-activity relationships of 7 beta-[(Z)-2-aryl-2-carboxymethoxyiminoacetamido]-3-vinylcepha losporins

The synthesis, antibacterial activity and oral absorption of the 7 beta -[(Z)-2-aryl-2-carboxymethoxyiminoacetamido]-3- vinylcephalosporins are described. Of these cephalosporin derivatives, 7 beta-[(Z)-2-(2-amino-4-thiazolyl)-2-carboxymethoxyiminoacetamido]- 3-vinylcephalosporin exhibited the highest activity against Gram-negative bacteria and showed also good excretion after oral administration to rats. In addition, the effects on the antibacterial activity and oral absorption of the amino function on the thiazole ring are discussed.     

Studies of 7 beta-[2-(aminoaryl)acetamido]-cephalosporin derivatives. I. Synthesis and structure-activity relationships in the aminopyridine series

The synthesis and in vitro activity of 7 beta-(2-aminopyridyl-2-alkoxyiminoacetamido)cephalosporins with various substituents at the 3-position are described. The effects of substitution pattern on the pyridine ring, oxime substituent and 3-substituent were studied as a function of the MIC values. Of these various kinds of derivatives, 7 beta-[2-(2-aminopyridin-6-yl)-2-alkoxyiminoacetamido]cephalo sporins exhibited significantly higher activity against most of micro-organisms.     

Studies on cephalosporin antibiotics. III. Synthesis, antibacterial activity and oral absorption of new 3-(substituted-alkylthio)-7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2- (carboxymethoxyimino)acetamido]cephalosporins

The synthesis, antibacterial activity and oral absorption in rats of new 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(carboxymethoxyimino)ace tamido] cephalosporins (1) having various substituted-alkylthio groups at the C-3 position of the cephem nucleus are described. Of these, the cephalosporins with a cyanomethylthio group (1d) and fluoroethylthio group (1p) at the C-3 position showed a potent in vitro antibacterial activity against Gram-positive and Gram-negative bacteria as well as good oral absorption in rats. When administered orally to mice infected with Klebsiella pneumoniae, 1d had stronger protective effect than 1p. The structure-activity relationships of 1 are also presented.     

Studies on cephalosporin antibiotics. IV. Synthesis, antibacterial activity and oral absorption of new 3-(2-substituted-vinylthio)-7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2- (carboxymethoxyimino)acetamido]cephalosporins.

A series of new 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(carboxymethoxyimino)ace tamido] cephalosporins (1) having various substituted-vinylthio groups at the C-3 position of the cephen nucleus was synthesized and evaluated for antibacterial activity and oral absorption in rats in comparison with cefixime. Of these, the cephalosporins (1a and 1c) with a lower alkoxycarbonylvinylthio group (Z-form) at the C-3 position showed a potent antibacterial activity against Gram-negative bacteria, improved activity against Staphylococcus aureus as well as good oral absorption in rats. The structure-activity relationships of 1 are also presented.     

New broad-spectrum cephalosporins with anti-pseudomonal activity. I. Synthesis and antibacterial activity of 7 beta-[D-2-[(4-hydroxy-1,5-naphthyridine-3-carbonylamino)- and (4-hydroxypyridine-3-carbonylamino)]-2-(4-hydoxyphenyl)acetamido] cephalosporins

The synthesis and the antibacterial activity of 7 beta-[D-2-[(4-hydroxy-1,5-naphthyridine-3-carbonylamino)- and (4-hydroxypyridine-3-carbonylamino)]-2-(4-hydroxyphenyl)acetamido]-cephalosporins with various substituents at the 3-position in the cephem nucleus are described. These compounds exhibited strong antibacterial activities against a variety of Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa and Enterobacter aerogenes, which are insensitive to cefazolin and cefmetazole. The compounds (3e, 4e) having a 1-methyl-1H-tetrazolylthiomethyl group at the 3-position appeared to show the best activity in each series. The 4-hydroxypyridine-3-carbonylamino derivative 4e gave higher peak serum concentrations and urinary recovery rates than those of the 4-hydroxy-1,5-naphthyridine derivative 3e when administered subcutaneously to mice and intramuscularly to rats.     

Studies on cephalosporin antibiotics. V. Synthesis, antibacterial activity and oral absorption of new 3-[(Z)-2-methoxycarbonylvinylthio]-7 beta- [(Z)-2-(2-aminothiazol-4-yl)-2-(oxyimino)acetamido]cephalosporins.

A series of new 3-[(Z)-2-methoxycarbonylvinylthio]-7 beta-[(2- aminothiazol-4-yl)acetamido]-cephalosporins (1) having various oxyimino groups (Z-form) at the alpha position of the C-7 side chain was synthesized and evaluated for antibacterial activity and oral absorption in rats. Of these, the cephalosporin (1a) with a hydroxyimino group in the C-7 side chain showed a potent antibacterial activity against Gram-negative bacteria and Gram-positive Staphylococcus aureus as well as good oral absorption in rats. The structure-activity relationships of 1 are also presented.     

Synthesis and antibacterial activity of 7 beta-[1-(2-aminothiazol-4-yl)-1-cyclopropanecarboxyamido]cephem derivatives

The synthesis and antibacterial activity of several 7 beta-[1-(2-aminothiazol-4-yl)-1-cyclopropanecarboxyamido]cep hem derivatives (1) are described. The structure-activity relationships of 1 are also presented.     

Semisynthetic beta-lactam antibiotics. II. Effect on antibacterial activity of ureido N-substituents in the 6-[(R)-2-[3-(3,4-dihydroxybenzoyl)-1- ureido]-2-phenylacetamido]penicillanic acids

The synthesis and the relationship between in vitro and in vivo activities of 6-[(R)-2-[3-(3,4-dihydroxybenzoyl)-3-R1-1-ureido]-2- phenylacetamido]penicillanic acids having C2 approximately 8 alkyl or substituted alkyl groups as the substituents (R1) are described. In this series, 6-[(R)-2-[3-(3,4-dihydroxybenzoyl)-3-(3-hydroxypropyl)-1-ureido] -2-phenylacetamido]penicillanic acid (1b, AO-1100) showed the most potent protective effect on mice in experimental Pseudomonas aeruginosa infections, although it did not have the strongest in vitro activity among the penicillins we synthesized.     

New broad-spectrum cephalosporins with anti-pseudomonal activity. II. Synthesis and antibacterial activity of 7 beta-[2-acylamino-2-(4-hydroxyphenyl)acetamido]-3-[ (1-methyl-1H-tetrazol-5-yl)thiomethyl]ceph-3-em-4-carboxylic acids

The influence of the chirality of the 7-acyl side chain and of various N-acyl moieties (A-CO-) on the in vitro activity of 7 beta-[2-acylamino-2-(4-hydroxyphenyl)acetamido ]-3-[(1-methyl-1H-tetrazol-5-yl)thiomethyl]ceph-3-em-4-carboxylic acids (6) was investigated. A cephalosporin having a 7-acyl side chain of S-configuration (6r) was only weakly active against Staphylococcus aureus and Klebsiella pneumoniae and was inactive against the other species tested. Among the various N-acyl moieties in the cephalosporins having a 7-acyl side chain of the R-configuration, the 4-hydroxypyridine-3-carbonyl moiety, unsubstituted or substituted with 5-bromo and/or 6-alkyl groups and the 4-hydroxy-1,5-naphthyridine-3-carbonyl moiety, unsubstituted or substituted with a 6-methyl and a 6-methoxy group gave the most active compounds. N-Ethylation of the 4-hydroxy-1,5-naphthyridine-3-carbonyl derivative and the 4-hydroxypyridine-3-carbonyl derivative (6p, 6q) resulted in a decrease of the in vitro activity.     

Synthetic cephalosporins. V. Synthesis and antibacterial activity of 3-alkylthio-7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(O-substituted oxyimino)acetamido]cephalosporins and related compounds

3-Alkylthio-7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(O-substituted oxyimino)acetamido]cephalosporins (6 and 7) and the 3-methoxy analogues (10) were prepared by coupling diphenylmethyl 7-amino-3-alkylthio-3-cephem-4-carboxylate (1 and 2) or diphenylmethyl 7-amino-3-methoxy-3-cephem-4-carboxylate with (Z)-2-(2-tritylaminothiazol-4-yl)-2-(O-substituted oxyimino)acetic acid (4), followed by deprotection and subjected to examination of antibacterial activities. The pivaloyloxymethyl esters (8 and 9) of the compounds (6 and 7) were also prepared and oral activities of these esters were compared with those of the parent compounds (6 and 7). The cephalosporins (6a-j and 7a-c) had potent and wide antibacterial spectra against Gram positive and Gram negative bacteria which were comparable to those of cefixime or cefteram. Among them, the cephalosporins (6f and 7c) and the pivaloyloxymethyl esters (8b and 9b) had good in vivo efficacy in mice against infections of Escherichia coli No. 29 and especially 8b showed high urinary recovery in mice.     

Studies on semi-synthetic 7 alpha-formamidocephalosporins. III. Synthesis and antibacterial activity of some 7 beta-[D-2-(aryl)-2-[(4-ethyl-2,3-dioxopiperazin-1-yl)carbonyl amino] acetamido]-7 alpha-formamidoceph-3-em-4-carboxylate derivatives

The synthesis and antibacterial activity of 7 beta-[D-2-(aryl)-2-[(4-ethyl-2,3-dioxopiperazin-1-yl) carbonylamino] acetamido]-7 alpha-formamidocephalosporins with various substituents at the C-3 position of the cephalosporin nucleus is described. Inhibition of Gram-positive and Gram-negative bacteria including beta-lactamase producing strains was observed with phenyl as the aryl residue. The 3,4-dihydroxyphenyl group further enhanced the activity against Gram-negative organisms; in this series, the 3-[(1-methyl-1H-tetrazol-5-yl)thiomethyl] and 3-[(1-carboxymethyl-1H-tetrazol-5-yl)thiomethyl] analogues (2 and 12b) exhibited exceptional activity against Gram-negative bacteria, including Pseudomonas aeruginosa.