Nefkens reagent

However, the ketone VI/63 did not undergo transamidation reaction either under acidic or under basic conditions5 When the primary amino function in VI/63 was protected (as a phthalide by Nefkens reagent [49] [50]), the planned transformation of VI/64 to VI/1 via VI/66, VI/68, VI/69, outlined above and in Scheme VI/14, was realized in an overall yield of 56 % [10]. The behavior of the ketone VI/63 suggest an aminoacetal formation of type VI/73 [51]. Such a compound can be of interest for metallion transport phenomena in plants, because isomers of VI/63 are natural products and may have some functions in nature. A detailed analysis of this abnormal behavior is in progress [51]. 

There are a number of other methods to selectively protect primary amines. Nefkens reagent selectively protects primary amines as shown below (Sos-novsky and Lukszo, 1986). The reaction of spermidine with formaldehyde... 

The phthaloyl (Phth) derivatives of amines, formed from amines and N-ethoxy-carbonylphthalimide (G.H.L. Nefkens, 1960), are acid-resistant imides, which can be easily deblocked by nucleophilic reagents, most conveniently by hydrazine. 

A novel type of acylating reagents, 0-acyl derivatives of iV-hydro-xyphthalimide, were introduced in 1963 by Nefkens and Tesser [27]. The designation active ester might be practical but in reality these highly reactive... 

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