2-Unsubstituted isoxazol-5(4H)-ones and
 -5(2H)-ones may be acylated by acid chlorides,
 anhydrides or carboxylic acids in the presence of carbodiimides, to give
 O- and N-acylated products. The solvent, the presence
 of base and the temperature are found to alter the product ratios
 dramatically, but the substituents present at C-3 have the greatest
 effect. Aliphatic acid anhydrides and chlorides generally react at
 nitrogen, but aroyl halides give significant proportions of
 O-acylated products. Limited success in converting
 O-aroyl to N-aroyl isoxazolones is reported.
                                    未取代的
异恶唑-5(4H)-酮和-5(2H)-酮可以通过在碳二
亚胺存在下与酰
氯、酸酐或
羧酸反应进行酰化,生成O-和N-酰化产物。溶剂、碱的存在以及反应温度都会显著影响产物比例,但C-3位上的取代基影响最大。脂肪族酸酐和酰
氯通常在氮原子上反应,而芳氧基酰
氯则会产生大量O-酰化产物。关于将O-芳酰基转化为N-芳酰基
异恶唑酮的报道中,成功案例有限。