Dimethylformamide dialkylacetals

Esterification with the aid of N,N-dimethylformamide dialkylacetals was described by Thenot et al. [35] (Scheme 4.7). The reaction is carried out by heating the reaction mixture in pyridine at 60°C for 10-15 min, or the derivatives can also be prepared on the column by injecting the components of the reaction mixture simultaneously by means of the same syringe. R can be selected according to the particular requirements, and the quantitative yield of the reaction is said to be adequate. 

The esterification of carboxylic acids can also be accomplished using synthetic equivalents of acetals of alkanols RCH(OR )2 (by acid catalysis), ortho-esters RC(0R )3 (by acid catalysis), and dialkylcarbonates C0(0R)2 (by base catalysis). A series of bifunctional reagents of this type—dimethylformamide dialkylacetals (CH3)2N-CH(0R )2—are available at present. These compounds also react with primary amino groups, that is used in derivatization of amino acids for GC analysis (Fig. 1). 

Fig. 1 One-step derivatization of amino acids by dimethylformamide dialkylacetals.

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