title: One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor.
abstract: The Bohlmann-Rahtz pyridine synthesis and the Hantzsch dihydropyridine synthesis can be carried out in a microwave flow reactor or using a conductive heating flow platform for the continuous processing of material. In the Bohlmann-Rahtz reaction, the use of a Brønsted acid catalyst allows Michael addition and cyclodehydration to be carried out in a single step without isolation of intermediates to give the corresponding trisubstituted pyridine as a single regioisomer in good yield. Furthermore, 3-substituted propargyl aldehydes undergo Hantzsch dihydropyridine synthesis in preference to Bohlmann-Rahtz reaction in a very high yielding process that is readily transferred to continuous flow processing.
authors.affiliation: Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QJ, UK.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Bagley
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Fusillo
authors.forename: Robert L
authors.initials: RL
authors.lastname: Jenkins
authors.forename: M Caterina
authors.initials: MC
authors.lastname: Lubinu
authors.forename: Christopher
authors.initials: C
authors.lastname: Mason
keywords: Bohlmann–Rahtz; Hantzsch dihydropyridine synthesis; continuous flow processing; ethynyl ketones; flow chemistry; heterocycles; microwave synthesis; multicomponent reactions; pyridine synthesis