An Efficient Synthesis of 3,4-Dihydro-2,2-Dimethyl-2h-Pyrano Coumarin Derivatives

Download this article as: 

5-Hydroxy-7-methoxy-2,2-dimethyl chroman (1) on condensation with ethyl acetoacetate in the presence of anhydrous aluminium chloride and phosphorous oxychloride gave 5-methoxy-9,10-dihydro-4,8,8-trimethyl pyrano(2,3-h) pyranocoumarin (2) In quantitative yield. The same reaction of hydroxychroman8,3 and 5 afforded the pyranocoumarins4 and 3 respectively. All these products were characterised by spectral means.

acetoacetate; hydroxychroman8; respectively