( ( A ( heterocyclic ( compound ( or ( ring structure ) ) ) ) ) ( ( is ( ( a ( cyclic compound ) ) ( that ( has ( atoms ( of ( ( ( ( at least ) two ) ( different elements ) ) ( as ( members ( of ( ( its ring ) ( -LRB- ( s -RRB- ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ heterocyclic) (NN compound) (CC or) (NN ring) (NN structure)) (VP (VBZ is) (NP (NP (DT a) (JJ cyclic) (NN compound)) (SBAR (WHNP (WDT that)) (S (VP (VBZ has) (NP (NP (NNS atoms)) (PP (IN of) (NP (NP (QP (IN at) (JJS least) (CD two)) (JJ different) (NNS elements)) (PP (IN as) (NP (NP (NNS members)) (PP (IN of) (NP (NP (PRP$ its) (NN ring)) (PRN (-LRB- -LRB-) (PRP s) (-RRB- -RRB-)))))))))))))) (. .)))
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s).
(ROOT (S (NP (DT A) (JJ heterocyclic) (NN compound)) (VP (VBZ contains) (NP (NP (NNS atoms)) (PP (IN of) (NP (NP (QP (CD two) (CC or) (JJR more)) (JJ different) (NNS elements)) (PP (IN in) (NP (PRP$ its) (NN ring) (NN structure))))))) (. .)))