| Abstract: | A procedure which utilizes a special sublimate condenser for preparation of pyromeconic acid (I) by decarboxylation of either meconic or comenic acid is reported. O-Alkylation of pyromeconic acid with ethyl β-diazopropionate ex situ yields ethyl β-(4H-pyran-4-on-3-yloxy)-propionate (II), acidic hydrolysis of which affords the free acid III. The acid III is refractory to ring-closure to a chromanone analog IV under a wide range of acidic conditions. O-Allylation of 1 gives 3-allyloxy-4H-pyran-4-one (V) as a low-melting crystalline solid. |
