Paal-Knorr pyrrole
SMARTS: [#6:5]-[C;R0:1](=[OD1])-[C;H1,H2:2]-[C;H1,H2:3]-[C:4](=[OD1])-[#6:6].[NH2;$(N-[C,N]);!$(NC=[O,S,N]);!$(N([#6])[#6]);!$(N~N~N):7]>>[C:1]1(-[#6:5])=[C:2]-[C:3]=[C:4](-[#6:6])-[N:7]-1
Conditions
Reactant 1: 1,4 dione. The two central carbon must have at least one H.
Reactant 2: primary amine or hydrazine.
R1, R2, R3: Ar, alkyl.
References
Amarath, J. Org. Chem., 1991, 56, 6924)
Other sources
Organic chemistry
Wikipedia