Disclosed are compounds of Formula A: (structurally represented) where “RG1”, “RG2a”, “RG4”, “RG5”, “MG1”, “n” and “m” are defined herein which compounds are antagonists of A2A receptor. Disclosed herein also are uses of the compounds described herein as antagonists of the A2a receptor in the potential treatment or prevention of neurological disorders and diseases in which A2A receptors are involved. Disclosed herein also are pharmaceutical compositions comprising these compounds and uses of these pharmaceutical compositions.