In view of the well known importance0”8) of 2- pyrazolin-5- ones as versatile intermediates for the synthesis of different types of hete¬rocyclic moieties, which may by substituted, condensed or fused to other systems, 4- hydroxymethyl -1- phenyl -3- methyl -2- pyrazolin -5- one (1) represents an adaptable starting material for this work.