Novel .BETA.-Lactam Antibiotics Synthesized by Amination of Catechols Using Fungal Laccase

Abstract

In preceding papers, we discussed the laccase-catalyzed amination of 2,5-dihydroxybenzoic acid derivatives with aminopenicillins and aminocephalosporins.2,3) The motive for our work was the global issue with resistant pathogenic bacteria, e.g. Streptococcus pneumoniae strains [4][5][6][7] and Staphylococcus strains, against currently available b-lactam antibiotics. [8][9][10][11] Aminated products like 2-(3,6-dioxocyclohexa-1,4-dienylamino)-2-phenyl-acetylamino-penicillanic acids and 2-(3,6-dioxocyclohexa-1,4-dienylamino)-2-phenyl-acetylamino-cephalosporanic acids 2,3) inhibited the growth of several Gram positive bacterial strains and protected mice against an infection with Staphylococcus aureus. After amination the 2,5-dihydroxybenzoic acid derivatives were units of the C-7 substituent of the b-lactam antibiotics.The possibility of utilizing catechol units as an element of the C-7 substituent of penicillins and cephalosporins was investigated for a long time. [12][13][14][15][16][17] Through the tonB dependent iron transport mechanism, 18) the use of catechol substituted b-lactams was known to increase the drug's penetration into the bacterial cell walls. Thus, several catechol-substituted blactams have been synthesized and showed good antimicrobial activities. [19][20][21][22][23] As a consequence of the promising activity of the catechol substituted b-lactams on one hand and the novel laccase-synthesized b-lactams on the other hand, we got interested in laccase-catalyzed amination of catechols with aminopenicillins and aminocephalosporins.In this study, we have employed laccase from Trametes sp. to derivatize amino-b-lactams and to couple them both with catechol and with substituted catechols. The novel b-lactams were structurally characterized as new coupling products inhibiting the growth of several Gram positive bacterial strains in the agar diffusion assay, among them methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci. The cytotoxicity of the new compounds and the effectiveness in a "Staphylococcus-infected, immune suppressed mouse" model are discussed. Results and DiscussionBiotransformation of Amino-b b-lactams by LaccasesLaccase-catalyzed reaction between catechols (substrates 1a to 1c) on one hand and the amino-b-lactams cefadroxil 2a, amoxicillin 2b, ampicillin 2c, and the structurally related carbacephem loracarbef 2d on the other hand led to cross coupled products (Table 1). 3-Methylcatechol and amino-b-lactams were consumed after an incubation time of 1.5 h, and monoaminated products (3a to 3d) were detectable by high-performance liquid chromatography (HPLC). If other catechols or longer reaction times were used, monoaminated products were only obtained in low yields and undesirable side reactions produced a number of by-products. Reaction kinetics similar to these findings were described for hybrid dimer formation from 3,4-dichloroaniline and syringic acid 24) or 3-(3,4-dihydroxy-phenyl)-propionic acid and 4-aminobenzoic acid. 25) In contrast, for hybrid dimer form...

Comparative analyses of laccase‐catalyzed amination reactions for production of novel β‐lactam antibiotics

“…Given the range of aromatic laccase substrates 16–19 and the known laccase‐produced β‐lactam antibiotics 5,6, we have chosen to study the para ‐dihydroxy aromatic acids 2,5‐dihydroxybenzoic acid 1a (gentisic acid) and 2,5‐dihydroxyphenylacetic acid 1b (homogentisic acid) and their derivatives 2,5‐dihydroxyphenylacetic acid methyl ester 1c and 2,5‐dihydroxyphenylacetic acid ethyl ester 1d and the ortho ‐dihydroxylated aromatic acids 3,4‐dihydroxybenzoic acid 1e (protocatechuic acid), 3,4‐dihydroxyphenylacetic acid 1f , and 3‐(3,4‐dihydroxyphenyl)‐propionic acid 1g (dihydrocaffeic acid) and their derivatives 4‐hydroxy‐3‐methoxybenzoic acid 1h (vanillic acid), 3,5‐dimethoxy‐4‐hydroxybenzoic acid 1i (syringic acid), and 3‐(3,5‐dimethoxy‐4‐hydroxyphenyl)‐2‐propenoic acid 1j (sinapinic acid) as laccase substrates in amination reactions. These substrates are structurally related to the laccase substrates previously used for the production of novel antibiotics 5–7 and therefore promised to yield the best results in terms of product stability, yield, and biological activity.…”

“…The use of laccase (EC1.10.3.2) for the derivatization of antibiotics is so far limited to a few examples 1, which include the phenolic oxidation of 7‐(4‐hydroxyphenylacetamido)‐cephalosporinic acid 2, the dimerization of penicillin X 3, and the oxidative coupling of hydroquinone and mithramicine 4. Furthermore, the laccase‐catalyzed amination of dihydroxyaromatics has been described as a new method to synthesize novel antibiotics by enzymatic transformation 5–10. The aminated products (heteromolecular dimers), consisting of one molecule of dihydroxybenzoic acid derivative and one molecule of β‐lactam antibiotic, inhibit the growth of several Gram‐positive bacterial strains and protect mice against an infection with Staphylococcus aureus .…”

Efficient production of Al(OH)3-immobilized laccase with aHeterobasidion annosumstrain selected by microplate screening

“…2005) to the grafting of molecules onto plasma‐treated polypropylene fibres (Schroeder et al. 2008) or the synthesis of novel β‐lactam antibiotics (Mikolasch et al. 2008).…”

Identification and Molecular Characterization of Genes Coding Pharmaceutically Important Enzymes from Halo-Thermo Tolerant Bacillus

“…28,29 Up to now, novel cephalosporins, penicillins, and carbacephems were synthesized by amination of amino-β-lactam structures using laccases. 13,28,30 Other examples of the potential application of laccases for organic synthesis include the oxidative coupling of katarantine and vindoline to produce vinblastine. 31 Vinblastine is an important anti-cancer agent, extensively used in treatment of leukemia.…”