Carcinogenic nitrogen compounds. Part LXXXI. Steric control in heterocyclic cyclisations with 6-substituted chrysenes

Abstract

It is shown that heterocyclic cyclisations with 6-substituted chrysenes, and involving position 5 are under the strict control of steric factors. Thus 6-hydroxychrysene readily afforded chryseno[6,5-b]furan, benzo[a]naphth[2,1-c]acridine, and polycyclic indoles, but failed to undergo a von Pechmann condensation with ethyl acetoacetate; N-phenyl-6-aminochrysene resisted Bernthsen acridine and phenothiazine syntheses and the Wieland–Rheinheimer reaction.