stirring 33 ml of conc sulfuric acid was slowly added this was refluxed for 15 minutes the clear cooled solution was poured over approx 200 ml of chopped ice the stirred mixture was brought to ph 0 5 1 0 ph meter by portion wise addition of a well stirred suspension of aqueous sodium bicarbonate 83 g sodium bicarbonate plus 600 ml water approx 90 of the suspension was used the acid solution was extracted with 7 u00d7 75 ml ether the combined extracts were dried over sodium sulfate the combined 525 ml extract was vacuum concentrated to approx 175 ml and with stirring a saturated aqueous solution of 1 1 potassium chloride potassium carbonate was added until the ether phase was approximately ph 6 ph paper and the aqueous phase was approximately ph 8 9 and the bubbling had stopped this was filtered through fast filter paper on a buchner funnel washed with a minimum of ice cold acetone and air dried a second crop was obtained by treating the combined 250 ml extract as for crop 1 except that the volume was first reduced to approx 75 ml this yielded 4 60 grams proton nmr dmso d6 no peaks carbon 13.