h 4 75 to a solution of compound 3 3 g 17 7 mmol in abs ethanol 30 ml was added sulfuric acid 0 5 g the mixture was refluxed for 5 hr and then the solvent was evaporated the residue was partitioned between chloroform and 10 potassium carbonate aqueous solution the separated chloroform layer was washed with water dried and evaporated to give compound 4 3 2 g 92 yield a solution of pyrone 4 10 2 g 52 0 mmol in saturated ethanolic ammonia 180 ml was heated at 120 u00b0 c in an autoclave for 48 hr the mixture was cooled and filtered to give compound 5 6 2 g as a white powder the filtrate was evaporated and the residue was triturated with small amount of cold methanol to give compound 5 1 7 g as the second crop the combined yield of compound 5 is 7 9 g 91 mp gt 200 u00b0 c 1 h nmr dmso d 6 u03b4 8 02 brs 1h 7 85 brs 1h 7 59 s 1h 2 01 s 3h 1 91 s 3h anal calcd for c 8 h 10 n 2 o 2 c 57 82 h 6 07 n 16 86 found c 57 62 h 6 03 n 16 72 a mixture of compound 5 1 6 g 9 6 mmol dimethyl sulfate 1 2 g 9 52 mmol and anhydrous potassium carbonate 4 1 g 29 7 mmol in acetone 50 ml was heated under reflux for 15 hr it was then filtered and washed with acetone the filtrate was evaporated and the residue was partitioned between ethyl acetate and water the organic layer was washed with water dried and evaporated to give compound.