Oxidation reactions of azines: XIII. Synthesis, molecular structure, and oxidation reactions of 3-methyl-3,3,4,4,5,6-hexahydro-1H,2H-spiro[benzo[f]isoquinoline-1,2-naphthalen]-1-one

The condensation of 3,4-dihydronaphthalen-1(2H)-one with methylamine and formaldehyde in acid medium gave N,N-bis(1-oxo-1,2,3,4-tetrahydronaphthalen-2-ylmethyl)methanamine hydrochloride which was converted into 3-methyl-3,3,4,4,5,6-hexahydro-1H,2H-spiro[benzo[f]isoquinoline-1,2-naphthalen]-1-one by heating in 48% aqueous HBr or 50% H2SO4. Oxidation of the spiro compound with KMnO4 initially involved the methylene group of the allylamine fragment with formation of the corresponding lactam which then underwent cis-dihydroxylation at C4a and C10b. Oxidation of the same compound with KMnO4 in the presence of some CH acids (trifluoroacetone and 4-bromoacetophenone) or aromatic amines (4-fluoroaniline and 2-bromo-4-nitroaniline) afforded, respectively, 4-acylmethylidene or 4-arylimino derivatives via C-C or C-N cross-coupling at the 4-position. © 2014 Pleiades Publishing, Ltd.