Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5222843 | Tetrahedron | 2010 | 4 Pages |
Abstract
The synthesis of two diastereomeric cyclo[Asp-N-Bn-Ser] diketopiperazines (2a and 2b) was investigated. Initial formation of the Boc-aspartyl-N-benzyl serine isopeptide methyl esters (4a and 4b) was observed, which derive from the selective O-acylation of unprotected (S)- or (R)-N-benzylserine. This unexpected O-acylation is preferred over the formation of the tertiary amide and the resulting ester bond is stable in solution to O,N-acyl transfer. The O,N-acyl migration is then triggered by cleavage of the Boc protecting group and treatment with base, which also promotes immediate cyclization to the diketopiperazines.
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Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Mattia Marchini, Michele Mingozzi, Raffaele Colombo, Cesare Gennari, Marco Durini, Umberto Piarulli,