Regioselective acylation of β-enaminones of homoveratrylamine

Abstract

The selective acylation of the aromatic ring of N-phenethyl enaminones is reported. A number of substituents in the β-enaminone structure and in the benzene ring have been prepared from different dicarbonyl compounds and carboxylic acids.

Diastereoselective intramolecular aldol ring closures of threonine derivatives leading to densely functionalised pyroglutamates related to oxazolomycin

“…In order to demonstrate that such intermediates could be used to perform the desired ring closing aldol reaction, one of them (6a) was hydrolysed to acid 7 and converted to malonamide 8 by DCC coupling with oxazolidine 1. Furthermore, during the course of this work, we found that acyl Meldrum's acids 5b-d could be opened directly with oxazolidine 1 (R ¼ H), 15,16,19,20 giving malonamides 9a-c very efficiently; these sequences provided access to variously substituted analogues replacing the methoxy group at the chain terminus of 8. We also expected that intermediates of type 6 would prove to be pivotal, since alkylation at either or both of the aand g-positions using standard conditions should be possible, providing access to diversely functionalised pyroglutamates aer cyclisation.…”

Biomimetic synthesis, antibacterial activity and structure–activity properties of the pyroglutamate core of oxazolomycin

“…Having demonstrated the feasibility of conducting efficient aldol reactions according to Fig. 1, it was of interest to improve this approach, and on the basis of recently published work, [35][36][37] we expected that direct opening of acylated Meldrum's acids 8c, d with oxazolidine 12 should be possible; if so, this would remove two steps from the synthesis. In the event, when the two starting materials 8c or 8d and 12 were simply heated at 60 °C in acetonitrile for 2 h, the desired amides 13a,b were readily formed and in good yield.…”

In silico identification of the active conformation of open-chain enaminones with anticonvulsant activity

“…The open-chain enaminones (OCE) are compounds whose functional group N-C=C-C=O is part of a flexible chain. Recent studies indicate that the OCEs could also show anticonvulsant activity based on the assumption that their flexibility could allow a more precise binding to the corresponding receptor (Cheng and Ju, 2010;Mahmud et al, 2010;Ivanov et al, 2007).…”