Potassium Carbonate → HCID 21842558, compound

Participants

Reaction Steps

Each of the commercially available 4-hydroxycoumarin, 7-hydroxycoumarin(R3 =R4 =R5 =H), 7-hydroxy-4-methylcoumarin(R4 =CH3), 3-chloro-7-hydroxy-4-methylcoumarin(R3 =Cl, R4 =CH3), and 7-hydroxy-3,4,8-trimethylcoumarin (R3 =R4 =R5 =CH3) was treated with potassium carbonate and a haloketone (chloroacetone, R1 =CH3 ; 2-bromoacetophenone, R1 =C6H5 ; 2-bromo-4'-fluoroacetophenone, R1 =C6H4F; 2-bromo-4'-chloroacetophenone, R1 =C6H4Cl; 2-bromo-4'-bromoacetophenone, R1 =C6H4Br; 2-bromo-4'-iodoacetophenone, R1 =C6H4I; 2-bromo-4'-methylacetophenone, R1 =C6H4CH3 ; 2-bromo-4'-nitroacetophenone, R1 =C6H4NO2 ; 2-bromo-4'-methoxyacetophenone, R1 =C6H4OCH3 ; 2-bromo-4'-phenylacetophenone, R1 =C6H4C6H5) in acetone to provide (2-oxo-2-phenyl ethoxy)-2H-1-benzopyran-2-one which was reacted with ethyl 2-(bromomethyl)acrylate in tetrahydrofuran(THF) (Reformatsky reaction) to produce 4-[(2,3,4,5-tetrahydro-3-methylene-2-oxo-5-furanyl)methoxy]-2H-1-benzopyran-2-ones and 7-[(2,3,4,5-tetrahydro-3-methylene-2-oxo-5-furanyl)-methoxy]-2H-1-benzopyran-2-ones as shown in Scheme 2.

Provenance & Evidence