Heterocyclic compounds: furan, pyrrole, thiophene, pyridine (intro)
Advanced Organic (UG) · Chemistry
Study notes
Why is pyrrole's N not basic but pyridine's N is? Step 1: Pyrrole: N's lone pair is part of the 6 π aromatic sextet (in p orbital). Step 2: Protonating it would destroy aromaticity → very unfavorable → not basic. Step 3: Pyridine: N's lone pair sits in sp² orbital, NOT in the π system. Step 4: Free to accept H⁺ → basic! Aromaticity decides basicity!