Microwave-assisted Piloty-Robinson synthesis of 3,4-disubstituted pyrroles.
The synthesis of N-acyl 3,4-disubstituted pyrroles can be accomplished directly from hydrazine and an aldehyde via a Piloty-Robinson pyrrole synthesis. The use of microwave radiation for the cyclization and pyrrole formation greatly reduces the time necessary for this process and facilitates moderate to good yields from hydrazine for the corresponding 3,4-disubstituted products (5-12). By simple hydrolysis, the free N-H pyrroles can be accessed after the Piloty-Robinson reaction and then used directly in the synthesis of octaethylporphyrin (H2OEP, 14) and octaethyltetraphenylporphyrin (H2OETPP, 15).
Milgram
Benjamin C
BC
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Eskildsen
Katrine
K
Richter
Steven M
SM
Scheidt
W Robert
WR
Scheidt
Karl A
KA
D001554:Benzene / Q000737:chemistry; D006358:Hot Temperature; D008872:Microwaves; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*
D011758:Pyrroles; D001554:Benzene