6-dioxopiperazin-2-yl]acetate 10 was synthesized in a four-step synthesis. Deprotonation of 10 and subsequent trapping of the first cyclization product led to the bicyclic mixed acetal 13 in 15% yield. The low yield of 13, compared with the yield of the corresponding glutamate derivatives, is explained by the higher energy (strain) of the bicyclo[2.2.2]octane system and the lower conformational flexibility of
Homologous piperazine-alcanols: chiral pool synthesis and pharmacological evaluation
作者:Ralph Holl、Dirk Schepmann、Bernhard Wünsch
DOI:10.1039/c2md20070h
日期:——
The diversity was introduced by N-1 alkylation of the piperazinediones 5 and 6 with various alkylhalides. Subsequent LiAlH4 reduction of the dioxopiperazine-esters 7 and 8 provided the alcohols 3 and 4. The ethanol derivatives 3 show similar σ1 affinity as the methanol derivatives 2, but increased selectivity over the σ2 subtype. The corresponding propanol derivatives 4 are considerably less potent