Photochemical synthesis of 8H-Benzo[g]- 1,3-benzodioxolo[6,5,4-de]quinolin-8-one (Liriodenine) via 7-Methyl-6,7-dihydro-5H-benzo[g]-1,3-benzodioxolo[6,5,4-de]-quinoline

Abstract

Irradiation of ethyl (Z)-1-(2-bromobenzylidene)-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline-2-carboxylate (4) afforded ethyl 6,7-dihydro-5H-benzo[g]-1,3-benzodioxolo[6,5,4-de]quinoline-7-carboxylate (5), the reduction of which with lithium aluminium hydride-aluminium chloride gave the 7-methyl derivative (6). Oxidation of (6) with lead tetraacetate afforded liriodenine (8H-benzo[g]-1,3-benzodioxolo[6,5,4-delquinolin-8-one)(1) in moderate yield.