Synthesis and late stage modifications of Cyl-derivatives

A peptide Claisen rearrangement is used as key step to generate a tetrapeptide with a C-terminal double unsaturated side chain. Activation and cyclization give direct access to cyclopeptides related to naturally occurring histone deacetylases (HDAC) inhibitors Cyl-1 and Cyl-2. Late stage modifications on the unsaturated amino acid side chain allow the introduction of functionalities which might coordinate to metal ions in the active center of metalloproteins, such as histone deacetylases.

Anomalies in the Stereoselectivity of the Petasis Reaction Using Styrenyl Boronic Acids

The Petasis three-component coupling reaction of N-benzylphenylglycinol, glyoxylic acid, and styrenylboronic acids allows for the efficient synthesis of functionalized homoarylalanine derivatives. The reactions were shown to proceed in high yield but low selectivity, regardless of the nature of the substituent on the styrenylboronic acid component. Anomalies in the stereoselectivity of these reactions compared with previously reported results have been traced to the source of the organoboronic acid. Asymmetric dihydroxylation of the unsaturated amino acid derivatives enables a highly efficient route to dihydroxyhomoarylalanine derivatives.

Synthesis of analogues of GABA. VIII. Selective a-alkylation and γ-halogenation of the dianion from α,β-unsaturated nipecotic acid derivatives

1,2,3,6-Tetrahydropyridine-3-carboxylic acid (3), the β, γ-unsaturated derivative of the GABA uptake inhibitor nipecotic acid (1), has been synthesized by deconjugation via the dilithium salt of the N-t-butyloxycarbonyl-protected intermediate (6). Substitution of the intermediate with alkylating agents or an aldehyde gave predominantly a-alkylated products but chlorination with N-chlorosuccinimide provided a route to the γ-substituted unsaturated amino acid (13a).