has specified reactant primary amine carboxylic acid molecular dehydration reaction molecular skeleton joining reaction Ugi reaction 4CC RXNO RXNO:0000129 Reaction of a ketone or aldehyde, amine, an isocyanide and carboxylic acid to form a bisamide. Ugi four-component condensation Ugi-4CR https://www.rsc.org/Merck-Index/reaction/r440/ https://www.wikidata.org/wiki/Q2002373