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
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
alkylation of the cycloadduct. The Diels–Alder reaction of γ-hydroxybutenolides with dienes gave good yields of cycloadducts under thermal and Lewis acid catalyzed conditions. The application of this methodology to a more complex system was demonstrated by the synthesis of a model system for the tricyclic himbacine core. The stereo- and regioselective Diels–Alder reaction established three of the stereogenic
synthesis of γ-hydroxybutenolides. The carbonyl group in butenolide holds the position of thiophenyl moiety in reacting furans. Decomposition of the initially formed [4 + 2] endoperoxide into products through a radical chain mechanism is proposed, as the fate of thiophenyl moiety is its transformation into ethyl phenylsulfenate (PhS-OEt) and diphenyldisulfide. Under the reaction conditions, the sulfenate is
KUO, YUEH-HSIUNG;SHIH, KAE-SHYANG;LEE, SHU-MEI, J. PHOTOCHEM. AND PHOTOBIOL. A, 45,(1988) N 1, C. 97-107
作者:KUO, YUEH-HSIUNG、SHIH, KAE-SHYANG、LEE, SHU-MEI
DOI:——
日期:——
Singlet-Oxygen Oxidation of 5-Hydroxymethylfurfural in Continuous Flow
作者:Thomas S. A. Heugebaert、Christian V. Stevens、C. Oliver Kappe
DOI:10.1002/cssc.201403182
日期:2015.5.22
AbstractSinglet‐oxygen oxidation of 5‐hydroxymethylfurfural (5‐HMF) was performed in continuous flow mode using rose Bengal as photosensitizer. The resulting butenolide (H2MF) was formed selectively in high yield. The procedure proved to be scalable and applicable to related bio‐based furfurals. Furthermore, preliminary data show that H2MF can be readily isomerized thermally to 5‐hydroxy‐4‐keto‐pentenoic acid oligomers.
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
作者:L. Cottier、G. Descotes、L. Eymard、K. Rapp
DOI:10.1055/s-1995-3897
日期:1995.3
The photooxygenation of 5-hydroxymethyl-2-furfural (1a) or derivatives 1b-g yields 4-hydroxy-Π2-butenolides 2 which are the precursors 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.