Synthesis of Novel 13a-(ω-Aminoalkyl)-8-oxoberbines by Means of Reaction of Homophthalic Anhydride with 1-Substituted 3,4-Dihydroisoquinolines. An Unexpected Formation of a Pyrrolo[3,4-<i>i</i>]berbindione
The reaction of 1‐[ω‐(N‐acylated amino)alkyl]‐3,4‐dihydroisoquinolines (7a, 7b, 7c, 7d, 7e) with homophthalicanhydride (1) leads to the formation of 8‐oxo‐13a‐[(N‐acylated amino)alkyl]‐8H‐dibenzo[a,g]quinolizine‐13‐carboxylic acids (8a–e) with predomination of cis diastereomers, together with small amount of trans-8a. cis‐13a‐[(N‐Cbzaminomethyl)]‐8‐oxo‐dibenzoquinolizine‐13‐carboxylic acid (cis-8a)