title: A novel and versatile entry to asymmetrically substituted pyrazines.
abstract: A novel and convenient procedure for the synthesis of asymmetrically tri- and tetrasubstituted pyrazines starting from para-methoxybenzyl-protected 3,5-dichloro-2(1H)-pyrazinones was elaborated. The key step is the conversion of the intermediate para-methoxybenzyl-protected thiopyrazinone upon treatment with MeI/I(2), into a pyrazine, rendering the chlorine in the C5-position susceptible to substitution. This approach entails the orthogonal introduction of the four substituents of the pyrazine scaffold. The application of microwave irradiation during different steps of the sequence has been shown to be highly valuable for speeding up reactions.
authors.affiliation: Laboratory for Organic and Microwave-Assisted Chemistry, Biomolecular Architecture, Department of Chemistry, University of Leuven (K. U. Leuven), Celestijnenlaan 200F, B-3001, Leuven, Belgium.
authors.forename: Vaibhav Pravinchandra
authors.initials: VP
authors.lastname: Mehta
authors.forename: Anuj
authors.initials: A
authors.lastname: Sharma
authors.forename: Kristof Van
authors.initials: KV
authors.lastname: Hecke
authors.forename: Luc Van
authors.initials: LV
authors.lastname: Meervelt
authors.forename: Erik Van der
authors.initials: EV
authors.lastname: Eycken
mesh_terms: D011719:Pyrazines / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D011719:Pyrazines