Synthesis of hydroxy tetronic acid

A Historical Introduction is given as background material to the problem of the existance of an ?-hydroxy-?-substituted tetronic acid as the intermediate in the oxidation of tetronic acids to ?-diketones. Three schemes are proposed by which this intermediate may be synthesized, starting with ethyl acetoacetate. In the first scheme the ?-substituted tetronic acid is oxidized by lead tetraacetate to the ?-acetoxy-?-substituted compound. In the second and third schemes, the lead tetraacetate oxidation can be applied to the ?-substituted acetoacetic ester, or the ?-substituted acetoacetic ester can be chlorinated with sulfuric chloride and then converted to the ?-acetoxy ester. Experimental work dealing with the lead tetraacetate oxidation is described, and the difficulties encountered discussed. The yields of ethyl ?-acetoxy-?-methylacetoacetate were low and thus more work is necessary before the proposed synthetic procedures are tested further.