Paal-Knorr Synthesis · One Diketone, Three Rings
unseel.com · 1,4-diketone → furan / pyrrole / thiophene · Paal & Knorr 1884
Heteroatom
Ring open chain
Step 1,4-diketone ready
Carbon skeleton (4 C)
Carbonyl / lost O (as H₂O)
Furan O · from acid
Pyrrole N · from R-NH₂
Thiophene S · from Lawesson's
Unseel.com · Paal-Knorr Synthesis