PYRROLE CHEMISTRY .9. A NEW SYNTHESIS OF 3-ACYLPYRROLES FROM 4-ACYL-2-PYRROLETHIOLCARBOXYLATES USING A CATALYTIC DECARBONYLATION REACTION

The Friedel-Crafts acylation reaction of ethyl 2-pyrrolethiolcarboxylate gives good yields of 4-acylated products. The thiolcarboxylate group is replaced by hydrogen on treatment with W5 Raney Ni under carefully controlled conditions and provides a new route to 3-acylpyrroles. The removal of 2-pyrrolethiolcarboxylate group by W5 Raney Ni appears to be quite general and using the reaction 3-acetyl-, 3-formyl-, 2-methyl-3-acetyl-, 2-methyl-3-formyl-, 2-acetyl- and 2-methyl-pyrrole have been prepared. © 1969.