Synthesis of the First Crystalline Thiaanthracenes, 9-Cyano- and 9-(Ethoxycarbonyl)-10-methyl-10-thiaanthracenes, and Their Reactions with Electrophiles

Article abstract of DOI:10.1021/jo01300a041

The isolable and crystalline thiaanthracene derivatives 9-cyano- (9) and 9-(ethoxycarbonyl)-10-methyl-10-thiaanthracene (12) were synthesized in high yield for the first time by proton abstraction from the corresponding thioxanthenium salts (8a or 8b and 11) with sodium hydride in THF under a nitrogen atmosphere.Upon standing in THF at 50 deg C, thiaanthracenes 9 and 12 underwent thermal 1,4-rearrangement to give the corresponding thioxanthenes 13 and 14, respectively.The ylidic property of the thiaanthracenes was manifested by spectral and chemical evidences.Reactions of the thiaanthracenes with electrophiles such as dimethyl acetylenedicarboxylate and tetracyanoethylene are also described together with the course of the reactions.