Post-condensation Modifications of the Passerini and Ugi Reactions

Multicomponent Reactions. Edited by Jieping Zhu. Hugues Bienayme Copyright 2005 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 3-527-30806-7 

The discovery of this behavior was of great importance because a single product was converted into a variety of products. The conversion into primary amides or other carboxylic acid derivatives depended upon the structure of the Ugi adducts. An electron-rich N-acyl moiety was required for the formation of munch -nones, otherwise the primary amide was obtained [7]. The conversion of cydo- 

In general, the hydrolysis of amides requires conditions that are not compatible with the survival of several functional groups [10]. If the amide nitrogen is linked to an electron-withdrawing moiety, alkaline hydrolysis of the amide group is easier. Following this observation Martens and co-workers used 4-methoxy-2-nitrophenyl isocyanide 14 (or 2-methoxy-4-nitrophenyl isocyanide) as a convertible isocyanide for the preparation of Peptide Nucleic Acid (PNA) monomers [8a] (for another example, see Ref. [11]). The Ugi-4CR between isocyanide 14, carboxymethyl nucleo- 

The transformation of secondary amides in the presence of the /Mactam ring has also been achieved by N-nitrosation of amides followed by thermal decomposition to esters, which were in turn hydrolyzed to the corresponding acids. Diphenyl-methyl isocyanide [14] and 4-nitrobenzyl isocyanide (PNBNC) [15] have been sue- 

Universal Rink Isocyanide-resin Safety Catch Linker Isocyanide-resin 

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Marcaccini S, Torroba T (2005) Post-condensation modifications of the Passerini and Ugi reactions. In Zhu J, Bienayme H (eds) Multicomponent reactions. Wiley-VCH, Weinheim, pp 33-75... 

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