The syntheses of 4b,5a‐dihydrodibenz[3,4:5,6]anthra[1,2‐ b ]oxirene and 4b,5a‐dihydro‐5 H ‐dibenz[3,4:5,6]anthra[1,2‐ b ]azirine

The syntheses of the K ‐oxide and K ‐imine derivatives of dibenz[ a,j ]anthracene ( 1 ) are described. The parent hydrocarbon 1 that was obtained as a side product in the Elbs pyrolysis of (2‐methyl‐1‐naphthyl)‐1′‐naphthylmethanone ( 10 ) was oxidized to 3‐(2‐formylphenyl)‐3‐phenanthrenecarboxaldehyde ( 3 ). Treatment of the dialdehyde with tris(dimethylamino)phosphine gave 4b,5a‐dihydrodibenz[3,4:5,6]anthra[1,2‐ b ]oxirene ( 4 ). Reaction of the oxirane with sodium azide followed by triethyl phosphite cyclization of the mixture of trans azido‐alcohols so formed, yielded mainly 4b,5a‐dihydrodibenz[3,4:5,6]anthra[1,2‐ b ]azirine ( 5 ).