N    Npl N. N3+
CA   C3
C    C2  OXT? Cac
O    O2  OXT? O2-
CB   C3
CG   Car
ND1  Npl
CD2  Car
CE1  Car
NE2  Npl
OXT  O2-
# better to default ring to aromatic and let AddH sort out the protation
# until ring-typing code improved