with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the hetero ring

Full Title

Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings > condensed with carbocyclic rings or ring systems > with only hydrogen or carbon atoms directly attached to the ring nitrogen atoms > Benzopyrazines > with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the hetero ring