<strong>Ultrasound-assisted synthesis of eight novel and highly functionalized 2-aminonitrile oxazoles via Ugi-3CR</strong>

Abstract

Eight novel 2-aminonitrile oxazoles were synthesized efficiently and quickly via an Ugi reaction in its three-component version in moderate to good yields (61-79%) at room temperature or in good to excellent yields (73-90%) under ultrasound irradiation (USI) conditions. It is noteworthy that not only the yields were improved by using USI, also the reaction times decreased considerably, from 3 hours (at r.t.) to 1 hour (under USI), depending on the substituents in the final products, which are highly functionalized because have an amino group, a nitrile group, an oxazole group and a very reactive methylene-linked biaryl. In this context, they can be used for further condensations, cyclizations and/or functionalizations toward a variety of compounds with potential applications in several fields of knowledge like optics, material science and medicinal chemistry.

Synthesis of Polyheterocyclic Pyrrolo[3,4-b]pyridin-5-ones via a One-Pot (Ugi-3CR/aza Diels-Alder/N-acylation/aromatization/SN2) Process. A Suitable Alternative towards Novel Aza-Analogues of Falipamil

“…These intermediates used as in situ were prepared to access to the polyheterocycles 11a – i in one-pot manner. Consequently, when intermediates 9a – i were detected by TLC (by typical features such as R f and spot nature [22]), 1.4 equiv. of the maleic anhydride ( 10 ) [23] was added to give the desired products 11a-i via a cascade triple process: N -acylation/aza Diels-Alder cycloaddition/aromatization (decarboxylation-dehydration) (Scheme 1).…”