André Loupy

New aromatic polyamides were synthesized by the microwave‐assisted polycondensation of an optically active isosorbide‐derived diamine with different diacyl chlorides in the presence of a small amount of N‐methylpyrrolidinone. Polymers with inherent viscosities between 0.22 and 0.73 dL/g were obtained corresponding to molecular weights up to 140,000 g/mol. With interfacial polymerization or the Higashi method, lower molecular weight polymers were obtained with inherent viscosities in the range of 0.04–0.36 dL/g. Differential scanning calorimetry measurements clearly demonstrated the high thermal stability of these polymers (mp = 180–300 °C) and the absence of decomposition. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6480–6491, 2005

Zn powder is found to catalyze the Friedel-Crafts acylation of aromatic compounds with acyl halides efficiently under microwave irradiation in solvent-free conditions. Activated substrates undergo acylation predominantly at the para-position. The Zn powder can be re-used up to six times after simple washing with diethyl ether and dilute HCl.

(2003). EFFECT OF CATIONS, SUBSTRATES AND TEMPERATURE ON THE MICROWAVE-ASSISTED SAPONIFICATION OF BENZOIC AND MESITOIC ESTERS. Organic Preparations and Procedures International: Vol. 35, No. 4, pp. 361-368.

A solvent-free protocol for the rhodium(I)-catalyzed intermolecular hydroacylation was achieved under microwave irradiation to furnish various ketones in high yields. The reactivity was improved by the addition of aniline as well as 2-amino-3-picoline and benzoic acid to induce a transimination, which facilitates the formation of intermediate aldimine. A comparison of the reactivity between the reaction performed under the conventional heating mode and the microwave irradiation using monomode reactor revealed an important specific microwave effect during the chelation-assisted hydroacylation. It is supposed that the observed specific microwave effect mainly originates from the formation of aldimine by condensation of aldehyde and amine, which leads to a development of charges in the transition state. This result confirms that the rate-determining step of the reaction is the initial condensation step rather than the subsequent hydroiminoacylation step.

Solvent-free condensation between malonic acid and aromatic aldehydes is studied in the presence of bentonite. Various diacids are prepared in good to moderate yields and in very short reaction times under microwave irradiation.