Heterocyclic Compounds, 4 or More Rings

**Definition:** A class of heterocyclic compounds that include four or more fused rings. Both aromatic or non-aromatic ring structures are included in this category.

**Tree numbers:** - D03.633.400

**Synonyms:** - Heterocyclic Compounds with Four or More Rings - Heterocyclic Cpds, 4 or More Rings - Heterocyclic Compounds with 4 or More Rings