George Marr

Organometallic derivatives of penicillins and cephalosporins a new class of semi-synthetic antibiotics

Abstract Novel semi-synthetic derivatives of penicillin and cephalosporin have been prepared in which the conventional phenyl or heteroaromatic group has been replaced by a ferrocene moiety, and in which the metal atom is in close proximity to the β-lactam ring of the antibiotic; several of the compounds exhibit high antibiotic activity and others are potent β-lactamase inhibitors.

A new class of semi-synthetic antibiotics: ferrocenyl-penicillins and -cephalosporins☆

Abstract A series of ferrocenyl carboxylic acids has been prepared and condensed, via their acid chlorides or in the presence of N , N ′-dicyclohexylcarbodiimide, with both 6-aminopenicillanic acid and 7-aminocephalosporanic acid. Almost all of the ferrocenyl-penicillins and -cephalosporins exhibited antibiotic activity, some being highly active, while others proved to be potent β-lactamase inhibitors.

The synthesis and reactions of homonuclear ferrocene acid anhydrides and their use in the preparation of ferrocenylpenicillins and -cephalosporins☆

Abstract 1,1′-Ferrocenediacetic acid anhydride and O -[1′-(carboxymethylferrocene] benzoic acid anhydride have been prepared and their reactions with amines investigated. These anhydrides have been shown to be useful for the preparation of heteroannularly substituted ferrocenyl-penicillins and -cephalosporins.

Oxidation of ferrocene and some substituted ferrocenes in the presence of horseradish peroxidase

Abstract The enzyme catalysed oxidation of ferrocene and some substituted ferrocenes to the corresponding ferricinium ions by hydrogen peroxide in the presence of native or immobilized horseradish peroxidase has been studied. Initial and maximum rates of oxidation have been determined. It was found that the oxidation was independent of the hydrogen peroxide concentration. The oxidation of ferrocene was effected also by horseradish peroxidase in a coupled system with glucose oxidase in the absence of any added hydrogen peroxide.

The synthesis and reactivity of ferrocenyloxy)-2-tetrahydropyran☆

Abstract Ferrocenylboronic acid was prepared in good yield via the base hydrolysis of ferrocenylboron dibromide. The ferrocenylboronic acid was converted into hydroxyferrocene which was treated with 2,3-dihydropyran to give (ferrocenyl oxy)-2-tetrahydropyran. Lithiation of this pyran gave the corresponding 2-lithiated ferrocene, which was used to prepare some 1,2-disubstituted ferrocenes including 1-carboxy-2-acetoferrocene (“ferrocenyl-aspirin”).

The ferrocene analogues of salicylic acid and aspirin

Abstract The reaction of hydroxyferrocene with 2,3-dihydropyran gave (ferrocenyloxy)-2-tetrahydropyran which on lithiation gave the corresponding 2-lithiated ferrocene which was used to prepare 1-carboxy-2-hydroxyferrocene and 1-carboxy-2acetoferrocene.

Polymer-supported biopolymer synthesis: 1. High load solid (gel) phase strategy for peptide synthesis with a phenolic poly(acryloylmorpholine)-based support

Abstract An efficient, low-cost, reaction strategy for the solid (gel) phase synthesis of peptides and protected peptide segments has been developed. The strategy involves the use of a new poly(acryloylmorpholine)-based phenolic support matrix, Koch-Light Peptide Resin A. Illustrative syntheses of N -terminal Boc- and Z -protected[Leu]- enkephalin derivatives, including C -terminal acid hydrazides and esters, are described. The strategy, which is effective for the synthesis of peptides at high matrix loadings, is adopted readily for large-scale application.

Organometallic derivatives V. The lithiation of ferrocenylmethyl cyanide

Abstract Ferrocenylmethyl cyanide has been dilithiated with n-butyllithium and condensation of the lithiated intermediate with benzyl chloride gave α,α-dibenzylferrocenylmethyl cyanide. The lithioferrocene was also condensed with methyl iodide, butylbromide and 1,2-dichloroethane to give the corresponding α-disubstituted ferrocenylmethyl cyanides. The reactions of these α-disubstituted ferrocenylmethyl cyanides with n-butyllithium and lithium aluminium hydride have been investigated.

Unsymmetrically disubstituted ferrocenes III. The synthesis of 2 substituted ferrocenylsilanes by lithiation of [(dimenthylamino)methyl]ferrocene

Abstract 2-Lithio[(dimethylamino)methyl] ferrocene has been condensed with chlorosilanes to give the corresponding 2-substituted ferrocenylsilanes. Some nucleophilic substitution reactions at the α-carbon of the methiodide of 2-(trimethylsily)[dimethylamino)methyl] ferrocene are described. The PMR and IR spectra of these compounds are discussed.

Organometallic derivatives : VII. The lithiation of (ferrocenylmethyl)diphenylphosphine oxide and sulphide☆

Abstract (Ferrocenylmethyl)diphenylphosphine oxide and sulphide have been lithiated with n-butyllithium under mild conditions. Metallation occurred on the α-carbon atom with both the oxide and the sulphide, and condensation of the lithiated intermediates with electrophiles gave a series of α-substituted ferrocenylmethylphosphines.