Derivatives of benzo[5,6]cyclohepta[1,2‐ b ]thiophene. Synthesis of 2,3,7,8‐tetrahydro‐3‐oxothieno[1,2‐ b ]cyclohepta[5,6,7‐ de ]isoquinoline and 1,2,3,7,8,11b‐hexahydro‐3‐oxothieno[1,2‐ b ]cyclohepta[5,6,7‐ de ]isoquinoline

The synthesis of the title compounds was carried out by cyclization via isocyanate of ( E )‐4,5‐dihydro‐10 H ‐benzo[5,6]cyclohepta[1,2‐ b ]‐thiophene‐10‐ylideneacetic acid and 4,5‐dihydro‐10 H ‐benzo[5,6]cyclohepta[1,2‐ b ]‐thiophene‐10‐ylacetic acid respectively, which were obtained by the Wadsworth‐Emmons modification of the Wittig reaction of 4,5‐dihydro‐10 H ‐10‐oxobenzo[5,6]cyclohepta[1,2‐ b ]thiophene and triethyl phosphonacetate. The structures of these new compounds are described.