Abstract
The reactions of diketene-acetone adduct (2, 2, 6-trimethyl-1, 3-dioxin-4-one) (1) with heteroxyclic ylides were investigated. Heating of the adduct with isoquinolinium bis (ethoxycarbonyl) methylide (3a) gave ethyl 1-acetyl-2-hydroxypyrrolo [2, 1-a] isoquinoline-3-carboxylate (6a). Under similar conditions, isoquinolinium cyano (ethoxycarbonyl)-methylide (3b) and phenacylide (3d) gave 1-acetyl-2-ethoxycarbonyloxypyrrolo [2, 1-a]-isoquinoline-3-carbonitrile (7) and 1-acetyl-3-benzoyl-2-hydroxypyrrolo [2, 1-a] isoquinoline (6d), respectively. Isoquinolinium dicyanomethylide (3e) reacted with the adduct in a different manner to give bis (6-methyl-4-oxo-4H-1, 3-oxazin-2-yl) methylide (8). Pyridinium ylides similarly reacted with the adduct to give indolizines and oxazinylmethylides.
