(Benzo[4, 5]cyclohepta[l, 2‐b]thiophen‐4‐ylidene)acetic Acids: Novel Non‐ulcerogenic Antiinflammatory Agents

Compound (Z)‐ 8a has been found to display interesting antiinflammatory activity. In order to prepare derivatives with a wide variety of substituents in the aromatic part of the molecule, a new synthesis of the key intermediates 9a‐g was developed starting from thiophene‐3‐carboxylic acid ( 11 ) and substituted benzyl bromides. The conversion of 9a‐g to 10a‐g follows a known procedure. Ketones 10a‐g , on reaction with alkyl (dialkoxy‐phosphoryl)acetate, followed by isomer separation and alkaline ester hydrolysis, yielded the desired derivatives (Z)‐ 8a‐g and ( E )‐ 8a‐g . The biologically most interesting compound (Z)‐ 8a is currently undergoing clinical trials.