Synthesis of novel functionalised symmetric bi-2(1H)-pyrazinones

A simple and convenient synthesis for functionalised bi-2(1H)-pyrazinones 9, 11a-h starting from 3,5-dichloro-2(1H)pyrazinones 7, 10a-h is described. The pyrazinone is homo-coupled by means of a Suzuki-type reaction of an in situ generated boronate. The reactions were carried out under conventional heating as well as under microwave irradiation and dramatic improvements in the rates and yields have been observed under the latter conditions.status: publishe

Upper rim appended hybrid calixarenes via click chemistry

We report the application of "click" chemistry for the synthesis of hybrid calixarenes appended on the upper rim with carbohydrate and N,C-protected α-amino acids. The chemoselective N- or C-deprotection of the α-amino acids and their subsequent transformation into dipeptides is described. The first example of a chemo-enzymatic synthesis on upper rim derived calix[4]arenes using trans-sialidase affords sialylated lactose calix[4]arenes. Our innovative chemo-enzymatic process paves the way for further applications. © 2007 American Chemical Society

In situ "click" assembly of small molecule matrix metalloprotease inhibitors containing zinc-chelating groups

10.1021/ol802286gOrganic Letters10245529-553

Multicomponent click synthesis of 1,2,3-triazoles from epoxides in water catalyzed by Copper nanoparticles on activated carbon

Copper nanoparticles on activated carbon have been found to effectively catalyze the multicomponent synthesis of β-hydroxy-1,2,3-triazoles from a variety of epoxides and alkynes in water. The catalyst is easy to prepare, reusable at a low copper loading (0.5 mol %), and exhibits higher catalytic activity than some commercially available copper sources. The regio- and stereochemistry of the reaction has been revised and unequivocally established on the basis of X-ray crystallographic analyses. An NMR experiment has been implemented for the rapid and unmistakable determination of the regiochemistry of the process. Some mechanistic aspects of the reaction have been also undertaken which unveil the participation of copper(I) acetylides.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; CTQ2007-65218 and Consolider Ingenio 2010-CSD2007-00006), the Generalitat Valenciana (GV; PROMETEO/2009/039), and FEDER. Y.M. acknowledges the ISO of the Universidad de Alicante for a grant