The preparation of seven new 8-diketones containing fluorinated groups is reported. The infrared spectra and enolic Acetylacetone and l,l,l-trifluoro-2,4-pentanedione were content of these @-diketones were determined and are noted.2 chlorinated and the products identified.The metallic cation plays an important role in the aldol type condensation of metallo acetic esters with acetophenone to form @-hydroxy esters, since the reaction may be realized satisfactorily with lithio, zinchalo and magnesiumhalo esters but not with sodio esters. The aldol condensation was realized with a sodio ester under special conditions but, under usual conditions, metal-hydrogen exchange between the sodio ester and the a-hydrogen of the ketone occurred to form a B-diketone.Moreover, sodio 8-hydroxy esters were found to be relatively unstable; they underwent the reverse aldol condensation even in refluxing ether. The reverse aldol condensation was realized also with lithio-and zinchalo-8-hydroxy esters, but much more drastic conditions were required. The success of the aldol condensation of lithio, zinchalo and magnesiumhalo esters with acetophenone is ascribed to the coordinating capacities of the metallic cations.

Potentiometric Determination of Apparent IonizationConstants.-Twenty-ml. aliquots of 0.01-0.02 formal amino acid in 0.05, 0.10 and 0.20 formal aqueous sodium chloride were titrated at 24.4 =t= 2.1°with standard 0.2 normal hydrochloric acid or sodium hydroxide using a Beckman Model G pH. meter equipped with No. 1170 and No. 1190E electrodes. The constants were evaluated analytically25•28 recognizing over-lapping ionizations in the case of ^-sulfamyl-DL-phenylalanine and correcting in every instance for the amount of acid or base added which did not react with the amino acid. As a check, several of the constants were also evaluated by the method of Speakman.27 The reduced data summarized in Table I were obtained from thirty-three independent titrations which revealed no significant dependence of the ionization constants upon ionic strength over the range studied.The values given are believed to be accurate to within 0.05 of a pK unit. Absorption Spectra.-All spectra were determined with a Beckman Model DU Quartz Spectrophotometer at a temperature of 25 ± 3°and at intervals of 2 µ or less from the lower limit of the instrument to 280 µ and then at 10 µ intervals to 320 µ.