Efficient cyclocondensation of 1-(2-hydroxyphenyl)-3-phenyl-1,3-propanedione to flavone in glycerol

EDWIN ALARCON; GABRIEL SATHICQ; AIDA L. VILLA; CONSUELO MONTES; PATRICIA VAZQUEZ; GUSTAVO ROMANELLI

Glasgow

Congreso; EUROPA-CAT X; 2011

Chromone skeleton (4H-benzopyran-4-one) compounds, bearing an aromatic ring in the oxygenated ring at C2 (flavones) or at C3 (isoflavones), are used in pharmaceuticals. The cyclocondensation of â-diketone (1), Figure 1, in several acid media [1 and references therein] gives flavone (2). That reaction has been successfully carried out on silica supported Keggin type HPAs based on W or Mo using acetic acid or toluene as solvents [1, 2]. In this way, the disadvantages regarding corrosion and environmental pollution of soluble mineral acid catalysts are avoided. Glycerol, obtained in high amounts from biodiesel production, is non-toxic and has promising physical and chemical properties as an alternative safer solvent [3]. In this contribution cyclocondensation was carried out in this media by using H3PMo12O40.nH2O (PMo) as Keggin type catalyst in homogeneous phase.