Synthetic studies of a constrained ring didemnin analog
作者:Scott C. Mayor、Amy J. Pfizenmayer、Richard Cordova、Wen-Ren Li、Madeleine M. Joullié
DOI:10.1016/0957-4166(94)80007-3
日期:1994.4
An asymmetric Diels-Alderreaction in the presence of 3.0 M lithiumperchlorate-diethylether was used to generate the initial stereochemistry for a cyclohexane amino acid (3), a key intermediate in the preparation of a fused ring didemnin analog. This constrained ring macrocycle should provide insight into the binding site conformation of the bioactive species.
The esterification of sterically hindered or non-nucleophilic alcohols may often be problematic. The reaction of alcohols with acid fluorides is reported to be superior to standard acid activation protocols frequently used for difficult esterifications. The acid fluoride methodology was used to produce a hindered linkage between a secondary alcohol (4) and a cyclohexyl amino acid 3, a key intermediate in the formation of a constrained ring didemnin analog.
Synthetic Routes to a Constrained Ring Analog of Didemnin B
作者:Scott C. Mayer、Amy J. Pfizenmayer、Madeleine M. Joullié
DOI:10.1021/jo951693i
日期:1996.1.1
The didemnin class of biologically active cyclodepsipeptides, isolated from a marine tunicate, has shown antitumor, antiviral, and immunosuppressive activities. Synthetic studies were undertaken to prepare a modified analog of one of the most potent congeners, didemninB (1). The side chain of the isostatine unit was tethered into the macrocycle viaa cyclohexane ring in order to provide a more rigid