A member of the class of pyrazines that is pyrazine in which three hydrogens at positions 2, 3 and 5 have been replaced by methyl groups. ChEBI: Trimethylpyrazine is a member of the class of pyrazines that is pyrazine in which three hydrogens at positions 2, 3 and 5 have been replaced by methyl groups. It has a role as a pheromone, a flavouring agent, an animal metabolite, a plant metabolite and a bacterial metabolite.