8 g 75 yield as a colorless oil in a 1 l round bottom flask equipped with a magnetic stir bar reflux condenser and a nitrogen line compound 3 diester d12 7 5 g 18 3 mmoles etoh 337 5 ml and water 37 5 ml were stirred to a solution 85 koh 26 6 g 402 mmoles was added in a single portion and the resulting mixture was refluxed for 3 h fifteen drops of the reaction was shaken with 15 drops of 1m hcl aq and 0 5 ml of et 2 o tlc of the et 2 o layer silica gel plate 10 etoac hexanes mobile phase visualization with kmno4 stain showed the diester was consumed the cooled overnight reaction was concentrated in vacuo to an orange oil which was dissolved in water 75 ml and acidified with 4n hcl u02dc 110 ml the precipitated solid was collected by filtration and washed with a small amount of h 2 o 2 u00d7 5 ml the solids were briefly air dried on the filter and then in vacuo at 40 u00b0 c overnight the off white solid 6 9 g was dissolved in hot ethanol 70 ml the yellow solution was treated with charcoal u02dc 1 g and filtered through a pad of.