New one-step procedure for the synthesis of 6H-chromeno[4,3-b]quinolines and 8a,9,14,14a-tetrahydro-8H-benzo[5,6]chromeno[4,3-b]quinolines

Schiff bases generated in situ from substituted anilines and 2-allyloxybenzaldehyde underwent acid-catalyzed intramolecular Diels-Alder reaction followed by dehydrogenation to give 6H-chromeno[4,3-b]-quinolines. Under analogous conditions, derivatives of 2-allyloxynaphthalene-1-carbaldehyde were converted into 8a,9,14,14a-tetrahydro-8H-benzo[5,6]chromeno[4,3-b]quinolines. Possible dehydrogenation mechanisms are discussed. Original Russian Text ? M.M. Tomashevskaya, O.A. Tomashenko, A.A. Tomashevskii, V.V. Sokolov, A.A. Potekhin, 2007, published in Zhurnal Organicheskoi Khimii, 2007, Vol. 43, No. 1, pp. 75–80.