Synthesis of 1-{4a,6-dimethyl-4a,9a-dihydropyrano-[3,4-b]indol-9(1H)-yl}ethanone

Heating of the bromination product of 4-methyl-3,6-dihydro-2 H -pyran with 4-toluidine or 2-bromo-4-methylamiline in triethylamine gave 4-methyl- N -(4-methylphenyl)- and N -(2-bromo-4-methylphenyl)-4-methyl-3,6-dihydro-2 H -pyran-3-amines which were converted into the corresponding amides by reaction with bromo- or chloroacetyl chloride. 1-{4a,6-Dimethyl-4a,9a-dihydropyrano[3,4- b ]indol-9(1 H )-yl} ethanone was synthesized in good yield by heating N -(2-bromo-4-methylphenyl)- N -(4-methyl-3,6-dihydro-2 H pyran-3-yl)acetamide in boiling toluene in the presence of palladium(II) acetate, triphenylphosphine, copper(II) acetate, triethylamine, and potassium carbonate.