Abstract Ninhydrin reacted expeditiously with thirteen active methylene compounds on montmorillonite K10 clay at room temperature to furnish, in 5 min, a Knoevenagel condensate in one case, aldols in six cases, aldol-derived cyclic hemiketals in three cases, and interesting products in the remaining three cases. Almost identical results were obtained, but faster, when the reactions were carried out in water on steam-bath. The ...
