PREPARATION AND CHEMICAL PROPERTIES OF 3-ACYL-5-ARYLIDENE-4-HYDROXY-2,5-DIHYDRO-2-OXOTHIOPHENS A NEW CLASS OF IMMUNOSUPPRESSIVE AGENT

The title compounds, which act as immunosuppressive agents by interference with the cell line responsible for antibody synthesis, have been prepared by the condensation of aromatic aldehydes with 3-acetyl-2,5-dihydro-4-hydroxy-2- oxothiophen. Immunosuppressive activity was greatly influenced by substituents in the benzene ring. The corresponding 3-acyl-2,5-dihydro-4-hydroxy-2-oxo-5-p- tolylazothiophens were inactive. The condensation products of 3-acetyl-5-arylidene-2,5-dihydro-4-hydroxy-2-oxothiophens with primary aliphatic or aromatic amines have been shown to be 3-(1-alkyl- or aryl-aminoethylidene)- 5-arylidene-2,4-dioxotetra-hydrothiophens. 3-Acetyl-5-p-fluorobenzylidene-2,5- dihydro-4-hydroxy-2-oxothiophen has been shown to isomerize in alkali or daylight to 1-acetyl-4-p-fluorophenyl-hydroxy-5-oxo-3-thiocyclopentene.