苯巴比妥系缩丙二酰脲衍生物。由于结构中脲与酰基相接的氮原子既与酰基产生P-π共轭,又与脲中羰基产生P-π共轭,分散了该氮原子上的P电子云密度,从而使酰脲的给电子共轭效应减少,酰基上的碳原子易受羟基的攻击开环水解,继而脱去CO_2生成主要分解产物苯乙基醋酰脲。其加水分解反应历程如下。 Phenobarbital-based malonylurea derivatives. Since the nitrogen atom of urea and acyl group in the structure conjugates with both P-π of acyl group and P-π of carbonyl group in urea, the density of P electron cloud on the nitrogen atom is dispersed, The electron conjugated effect is reduced. The carbon atom on the acyl group is susceptible to hydroxyl attack and ring-opening hydrolysis, which then takes off CO 2 to form the major decomposition product phenethylurea. The hydrolysis reaction process is as follows.