Syntheses of γ-oxo acids or γ-oxo esters by photooxygenation of furanic compounds and reduction under ultrasound: Application to the synthesis of 5-aminolevulinic acid hydrochloride

Article abstract of DOI:10.1055/s-1995-3897

The photooxygenation of 5-hydroxymethyl-2-furfural (1a) or derivatives 1b-g yields 4-hydroxy-Δ²-butenolides 2 which are the percursors of butenolides 3 or α,β-unsaturated γ-oxo esters 5. The selective reduction of olides 2 or oxo esters 5 with zinc in acetic acid under sonication leads to γ-oxo acids 4 or γ-oxo esters 6. The photooxygenation of amino derivative 1d, followed by selective reduction of corresponding lactone 2d, gives 5-aminolevulinic acid hydrochloride (7) (ALA) after hydrolysis.