Abstract
Investigations on the essential conformation of adrenergic catecholamines led us to synthesize 6-amino-1, 2-dihydroxy-6, 7, 8, 9-tetrahydro-5H-benzocyclohepten-5-ol derivatives (1), which are seven-membered rigid analogues of catecholamines. Although catalytic reduction of the amino ketones (9 and 10) leading to the analogues of noradrenaline and isoproterenol (1a and 1c) yielded mixtures of 5, 6-cis and trans isomers, it was found that lithium aluminum hydride reduction of α-hydroxyimino ketone (12) gave exclusively cis-amino alcohol (13a-cis) and that reduction of α-acetamido ketone (14) with sodium borohydride followed by hydrolysis afforded 13a-trans. Several pairs of 5, 6-cis and trans isomers of 1 were prepared by catalytic reduction of 13a-cis and 13a-trans or their Nsubstituted derivatives. N-tert-Butyl derivative (1d-trans) was prepared via 13d-trans which was obtained by hydrolysis of an azirizino compound (24).
