Abstract
@-Tides have been shown to have the same characteristics as a peptide in the β-strand conformation and to have the ability to self-associate into dimeric β-sheets. Aza-cyclohexaenaminones, obtained by condensation of a protected azacyclohexa-3,5-dione and amino acid esters, are the key building-blocks in the synthesis of @-tides. An improved three-step synthetic sequence to these enaminones has been developed that takes advantage of microwave-assisted chemistry in two of the steps to enhance the reaction rates. It was also found that the enaminone building blocks can be obtained by direct condensation of the aza-cyclohexa-3,5-dione with amino acid esters, without prior activation of the diketone. Multivariate design was used to optimize this microwave-assisted condensation, resulting in a short reaction time (300 s) and high yields (67-94%).
Key words
enaminones - β-strand mimetics - microwave-assisted synthesis - multivariate design - optimization
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