A Convenient One-pot Synthesis of New 3-(4-Aryl-5-oxo-5,6,7,8- tetrahydro-4H-chromen-2-yl)-2H-chromen-2-ones

Abstract

Anhydrous zinc bromide catalysed reactions of arylidine-3-acetyl coumarins (1a-c) and 5,6- benzoanalogs of arylidine 3-acetyl coumarins (4a,4b) with 1,3-cyclohexanedione gives 3-(4-aryl-5-oxo- 5,6,7,8-tetrahydro-4H-chromen-2yl)-2H-chromen-2-ones (3a, 3c) and 5,6-benzoanalogs of 3-(4-aryl-5- oxo-5,6,7,8-tetrahydro-4H-chromen-2yl)-2H-chromen-2-one (5a,5b). Under similar conditions arylidine-3- acetylcoumarins (1a, 1b,1d, 1e, 1f) and 5,6-benzoanalog of arylidine 3-acetyl coumarin (4b) react with 5,5-dimethyl-1,3-cyclohexanedione (dimedone) yielding 3-(4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro- 4H-chromen-2-yl)-2H-chromen-2-ones (3d-3h) and the 5,6-benzoanalog of 3-(4-aryl-7,7-dimethyl-5-oxo- 5,6,7,8-tetrahydro-4H-chromen-2-yl)-2H-chromen-2-one (5c).