pyrazine (chemistry)

phenazine (loanword)

piperazine (medicine) (loanword)

an organic heterocyclic compound with the molecular formula C4H4N2, specifically the 1,2-diazine isomer

oxazine C4H5NO

thiazine (chemistry) (loanword)

A class of heterocyclic organic compounds containing nitrogen in a six-membered ring, or the suffix used to name them.

(loanword) cetirizine