Structure of Phenanthrene:
Phenanthrene is a polycyclic aromatic hydrocarbon composed of three fused benzene rings arranged in a linear arrangement.
Its molecular formula is C14H10.
Synthesis:
From Coal Tar:
Phenanthrene is extracted from the high boiling fraction of coal tar.
Laboratory Synthesis (Bardhan-Sengupta Synthesis):
Condensation: Benzene is condensed with phthalic anhydride in the presence of aluminum chloride.
Reduction and Cyclization: The resulting product undergoes reduction and cyclization to form phenanthrene.
Benzene + Phthalic anhydride → AlCl3 (Reagent) → Phenanthrene
Reactions:
Electrophilic Substitution:
Nitration: Phenanthrene reacts with nitric acid to form nitro phenanthrene.
C14H10 + HNO3 → H2SO4 (reagents) → C14H9NO2 + H2O
Sulfonation: Phenanthrene reacts with sulfuric acid to form phenanthrene sulfonic acid.
C14H10 + H2SO4 → C14H9SO3H + H2O
Oxidation:
Phenanthrene can be oxidized to phenanthrenequinone using oxidizing agents such as chromic acid (H2CrO4).
C14H10 + 2[O] → C14H8(O)2
Derivatives:
Phenanthrenequinone: A derivative formed by the oxidation of phenanthrene, used in organic synthesis.
Alkylated Phenanthrenes: Important in the study of polycyclic aromatic hydrocarbons and environmental pollutants.
Medicinal Uses:
Derivatives: Phenanthrene derivatives, such as phenanthridine alkaloids, have been studied for their potential anti-cancer, anti-inflammatory, and antimicrobial activities.
However, phenanthrene itself is not commonly used in medicine due to its carcinogenic properties.