Synthesis of 5-bromo-6-methyl imidazopyrazine, 5-bromo and 5-chloro-6-methyl imidazopyridine using electron density surface maps to guide synthetic strategy

Small heteroaromatic rings are valuable monomers in drug discovery that can enable rapid access to novel and desirable chemical space. Installation of a synthetic handle on a heteroaromatic core may be difficult if steric and electronic factors are not in alignment with the desired transformation. Described are practical routes for the construction of 5-bromo-6-methyl imidazopyrazine (1) as well as 5-bromo and 5-chloro-6-methyl imidazopyridines (2a and 2b), which were developed using electron density surface maps encoded with ionization potential to guide synthetic strategy. (C) 2011 Elsevier Ltd. All rights reserved.