Solution versus Fluorous versus Solid-Phase Synthesis of 2,5-Disubstituted 1,3-Azoles. Preliminary Antibacterial Activity Studies
摘要:
A small library of compounds with an oxa(thia)zole scaffold and structural diversity in both positions 2 and 5 has been synthesized. Double acylation of a protected glycine affords intermediate alpha-amido-beta-ketoesters, which in turn can be dehydrated to afford 1,3-oxazoles or reacted with Lawesson's reagent to furnish 1,3-thiazoles. This procedure was designed with its adaptation to fluorous techniques in mind. Thus, when a protected glycine With a fluorous tag in the ester moiety IS used as a starting material, the synthesis can be easily completed Without column chromatography purification of intermediate compounds with good to excellent yields, thus affording a Suitable entry to the preparation of small libraries of these bioactive compounds. The prepared oxa(thia)zoles were assayed for their antibacterial activity, and several of them were active against Staphylococcus aureus.
Synthesis of Oxazoles from Enamides via Phenyliodine Diacetate-Mediated Intramolecular Oxidative Cyclization
摘要:
A group of functionalized oxazoles were synthesized in moderate to good yields from enamides via phenyliodine diacetate (PIDA)-mediated intramolecular cyclization. The main advantageous features of the present method include its broad substrate scope and the heavy-metal-free characteristic of the oxidative carbon-oxygen bond formation process.
for the synthesis of 2,4,5-trisubstituted oxazoles has been developed from the direct coupling of α-diazoketones with aryl or alkyl nitriles. The reaction proceeds through the formation of nitrilium ion by the nucleophic addition of nitrile onto diazo functionality followed by an intramolecular trapping of nitrilium ion by keto group. Both aryl, and alkyl nitriles underwent smooth cyclocondensation