Experiments in the 5H-dibenzo[a,d]cycloheptene series II. Synthesis of some esters and piperazine derivatives of 5H-dibenzo[a,d]cycloheptene†

The synthesis of a number of acids in the 5H-dibenzo[a,d]cycloheptene series is described including the 5-carboxylic acid and its 10,11-dihydro analogue, 5H-dibenzo[a,d]cycloheptene-5-acetic acid and its 10,11-dihydro derivative. The latter acid was prepared by several routes. Treatment of its acid chloride with stannic chloride yielded 2,6,7,1 1b-tetrahydro-1H-dibenzo[c,d,h]azulen-2-one, which by reductive amination with methylamine, dimethylamine and 1-methyl-phenethylamine was converted into the corresponding amines. Several esters with aliphatic and heterocyclic amino alcohols were prepared from the carboxylic acids mentioned. The acids were likewise converted into 1-substituted 4-piperazides which were reduced to the corresponding piperazine derivatives. The acid derivatives were screened for biological activity.