Synthesis of [9, 10-dihydro-9-(4-methylaminobutyl)-9, 10-propanoanthracene] using Diels–Alder cycloaddition

The synthesis of [9, 10-dihydro-9-(4-methylaminobutyl)-9, 10-propanoanthracene] (2) as a homolog of the antidepressant [9, 10-dihydro-9-(3-methylaminopropyl)-9, 10-ethanoanthracene] (1) is described in the present paper. The key intermediate [9, 10-dihydro (4-pentyl)-9, 10- propanoanthracene-12-one] (7) is successfully synthesized by using the reaction of α-bromoacrolein with 9-pent-4-enyl-anthracene (4) followed by ring expansion and samarium diiodide deoxygenation.