Versatile electrophiles N-acylhydrazones are synthesized via diazotization, reduction, and acylation of α-amino acid esters. Reduction of diazo esters with L-selectride® or tributylphosphine affords the corresponding hydrazones in good yields. Both reducing agents give anti-hydrazones as the major product although the reactivity of each reductant is slightly different. The resulting hydrazones are acylated to give N-acylhydrazones, which are subjected to further reactions to give 1,3,4-oxadiazin-6-ones that serve as useful synthetic intermediates for the Diels–Alder reaction.
通过对
α-氨基酸酯进行重氮化、还原和酰化,可合成多功能亲电体 N-酰
肼。用 L-selectride® 或
三丁基膦还原重氮酯,可以得到相应的
肼,而且收率很高。尽管每种还原剂的反应性略有不同,但两种还原剂都会产生主要产物反
肼。生成的
肼经酰化后可得到 N-酰
肼,再经进一步反应可得到 1,3,4-恶二嗪-6-酮,它们是 Diels-Alder 反应的有用合成中间体。