Carboxylic acids overview

Table 7 Overview of ID50 values in vitro of condensation compounds of Bu2SnO with F -containing carboxylic acids against MCF-7 and WiDr...

The biocatalytic reduction of carboxylic acids to their respective aldehydes or alcohols is a relatively new biocatalytic process with the potential to replace conventional chemical processes that use toxic metal catalysts and noxious reagents. An enzyme known as carboxylic acid reductase (Car) from Nocardia sp. NRRL 5646 was cloned into Escherichia coli BL21(DE3). This E. coli based biocatalyst grows faster, expresses Car, and produces fewer side products than Nocardia. Although the enzyme itself can be used in small-scale reactions, whole E. coli cells containing Car and the natural cofactors ATP and NADPH, are easily used to reduce a wide range of carboxylic acids, conceivably at any scale. The biocatalytic reduction of vanillic acid to the commercially valuable product vanillin is used to illustrate the ease and efficiency of the recombinant Car E. coli reduction system." A comprehensive overview is given in Reference 6, and experimental details below are taken primarily from Reference 7. 

In Part 111 we cover that broad category of organic compounds called the carbonyls. First we give you an overview of Ccirbonyl basics, including structure, reactivity, and spectroscopy. Then we go into more detail on aldehydes and ketones, enols and enolates, and carboxylic acids and their derivatives. 

Monocarboxylic acid complexes have occupied a central position in coordination chemistry from the 19th century through to the present day.1,2 Ubiquitous is an adjective frequently and appropriately used in conjunction with this ligand in any overview of coordination chemistry. Reasons for this omnipresence of, particularly, acetic acid (ethanoic acid), an early member of this series, include its convenient properties (b.p. 117.7°C, f.p. 16.6 °C), ready availability (millions of tonnes produced annually) and its versatile coordination behaviour. Despite this long and intensive exposure as a ligand, carboxylic acids still continue to provide coordination chemists with exciting new species as any survey of the current literature will confirm. 

Theoretical studies have been reported for the neutral29 and alkaline30,31 hydrolysis of formamide. A theoretical study of the acid hydrolysis of iV-formylaziridine concluded that both N- and O-protonated pathways compete.32 In an historical overview of tetrahedral intermediates in the reactions of carboxylic acid derivatives with nucleophiles, several citations of amide reactions are included.33... 

Stilbenoids are derived from cinnamic acid and three acetate units from mal-onyl coenzym A. The first part of the biosynthesis is in common to flavonoids. The two biosynthetic routes are diverging at the point of cyclization of a styryl-3,5,7-triketoheptanoic acid. A C-acylation produces a chalcone and subsequent modifications lead to the flavonoids. An aldol condensation of the same intermediate polyketide produces a stilbene-2-carboxylic acid that is unstable and constitutes a range of structures known as stilbenoids. Figure 9C.5 shows an overview of the biosynthetic pathway (Gorham 1995). 

Figure 5.6. Overview of the Gridding and Partitioning (GaP) procedure as applied to monomers, exemplified using phenylalanine as a potential primary amine. This molecule thus contains two pharmacophoric groups (the aromatic ring and the carboxylic acid). During the conformational analysis the locations of these pharmacophoric groups are tracked within a regular grid. See color insert. [Reproduced from A. R. Leach and M. M. Hann, Drug Discovery Today, 5, 326-336 (2000),...

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