was dried mgso 4 filtered and concentrated to give 18 5 g of crude methyl 1 ethyl 1 3 4 9 tetrahydro 8 2 2 2 trifluoroethoxy pyrano 3 4 b indole 1 acetate as an oil this oil was dissolved in methanol 300 ml containing koh 11 g and water 10 ml and refluxed for 3 hours the solution was concentrated water added and washed twice with ether the aqueous solution was acidified with 6n hcl and extracted thrice with chloroform the combined chloroform extracts were washed with water dried mgso 4 filtered and concentrated to give 7 75 g of solid recrystallization from benzene petroleum ether afforded 5 5 g 57 of pure 1 ethyl 1 3 4 9 tetrahydro 8 2 2 2 trifluoroethoxy pyrano 3 4 b indole 1 acetic acid m p 126 u00b0 129 u00b0 c a mixture of 3 methyl 2 nitrophenol 50 g 0 326 mol k 2 co 3 45 g 0 326 mol and benzylbromide 61 4 g 42 6 ml 0 359 mol in dry dmf 200 ml was stirred at 90 u00b0 c for 3 hours under nitrogen most of the dmf was removed at reduced pressure and the residue was.