Quinoxalinecarboxylic esters

Formation constants and thermodynamic parameters have been measured for the Fe(II) chelates of 3-chloro-2-quinoxalinecarboxylic acid and 3-oxo-3,4-dihy-dro-2-quinoxalinecarboxylic acid.  

This section covers the preparation and reactions of quinoxalinecarboxylic esters, generally the most convenient derivatives of quinoxalinecarboxylic acids. 

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Two reactions of quinoxalinecarboxylic esters have been covered already reduction to hydroxyalkylquinoxalines (Section 4.3.2) and hydrolysis to quinoxaline carboxylic acids (Section 7.1.1). Other reactions are illustrated in the following classified examples. 

Reactions. Quinoxalinecarbonyl chlorides are occasionally used to make the corresponding quinoxalinecarboxylic esters (see Section 7.2.1) but more often to make quinoxalinecarboxamides or the like. Typical examples of such reactions follow. 

The main routes to quinoxalinecarbaldehydes were outlined earlier by primary synthesis (Chapter 1), by controlled oxidation of alkyIquinoxalines (Section 2.2.4), from mono- or dihalogenomethyIquinoxalines three procedures) (Sections 3.4.2 and 3.4.5), by oxidation of hydroxy alky Iquinoxalines (Section 4.3.2), and by reduction of quinoxalinecarboxylic esters (Section 7.2.2). Other methods of preparation are illustrated in the following examples. 

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