mixture of butyl acetate and tert butylmethylether mtbe 50 ml the filter cake is dried in vacuo and 23 3 g of product 6 are obtained 71 of theoretical compound 3 7 7 g is placed in butyl acetate 65 ml sodium hydroxide solution 25 ml 45 and water 25 ml and heated to 50 u00b0 c then the phases are separated and the organic phases are extracted again with water 30 ml the organic phase is combined with sodium iodide 1 54 g sodium hydrogen carbonate 4 00 g tetrabutylammonium iodide 0 75 g compound 6 10 0 g cyclohexane 65 ml and water 30 ml and stirred for 2 h at 40 u00b0 c then the cyclohexane is distilled off in vacuo butyl acetate 95 ml is added and the mixture is stirred for 2 h at 70 u00b0 c then the phases are separated and the organic phase is extracted twice with water 10 ml the organic phase is evaporated down in vacuo the solution is cooled to 0 u00b0 c and filtered the product is washed with butyl acetate 30 ml the filter cake is dried in vacuo and 13 8 g product 7 are obtained 87 8 of theoretical compound 7 20 g is suspended in acetone 238 ml at ambient temperature and refluxed the.