The synthesis of thienocycloheptenoindoles

A synthesis of the methylthieno[3,2‐ c ]cyclohepteno[ b ]indole 7 from 2‐methylthieno[3,2‐ b ]cycloheptanone 3 is described. Unsuccessful attempts to prepare the isomeric thienocycloheptenoindole system present in formula 2 , from the dihydrobenzothiophenone 8 , and from derivatives of 5‐(2‐thienyl)‐4‐oxopentanoic acid, 17 and 18 , and from N ‐benzylcycloheptindol‐1‐one 22 were unsuccessful. The preparation of 4,5‐dihydro‐2‐phenyl‐1‐thienylmethyl‐3 H ‐pyridazin‐3‐one 20 and of the 5‐aminopyrazole 21 are reported.