抗菌性ピロン誘導体に関する研究 (第1報)

デヒドロ酢酸の合成研究 (液相法)

抄録

Reëxamination was carried out on the synthesis of dehydroacetic acid by the liquid condensation of ethyl acetoacetate, and it was found that silver oxide, barium oxide, and magnesium oxide catalyst also gave a good yield besides the usual catalyst of sodium bicarbonate. From the pyrolytic decomposition of dehydroacetic acid, especially in the case of using sodium bicarbonate, it was also observed that the dehydroacetic acid formed underwent pyrolytic decomposition at a reaction temperature above 190°. When the reaction temperature was kept below 190°, the theoretical yield against the consumed ester was increased although there was an increase in the recovery of the ester. This tendency was also observed in the case of magnesium oxide. Use of ion exchange resin, such as Diaion K (sodium form), Diaion A (hydroxyl form), and Amberlite IR-120 (sodium form), as a catalyst resulted in milder reactions and theoretical yield reached approximately 50%. Other catalysts give a large amount of tarry residue so that the ion exchange resins may possibly have specific catalytic effect.