Hydrazine and azapeptide analogs were synthesized effectively by alkylation of alkylidene carbazates and semicarbazones. In comparisons of benzylidene, benzhydrylidene, and fluorenylidene tert-butyl carbazates in alkylations using bases of different pKb character, superior conversion was obtained using the fluorenone derivative. Mild alkylation conditions were found employing Et4NOH as base and used to convert fluorenylidene tert-butyl carbazate into 13 different protected hydrazines. Moreover, racemization was avoided during alkylation of fluorenylidene semicarbazide in the synthesis of aza-propargylglycinylphenylalanine tert-butyl ester, the protecting groups from which could be selectively removed.
通过烷基化反应合成了联苯肼和氮代肽类似物,利用不同pKb值特性的碱对苄基联苯甲酰肼、苄氢基联苯甲酰肼和芴基联苯甲酰肼进行烷基化比较,结果表明使用芴酮衍生物可以获得更高的转化率。采用Et4NOH作为碱的温和烷基化条件被发现,用于将芴基联苯甲酰肼转化为13种不同的保护肼。此外,在合成氮代-丙炔基甘氨酸苄基酯时,避免了芴基半卡巴酰胺的烷基化过程中的外消旋作用,该化合物的保护基可以选择性地去除。