64 s 3h 3 64 s 6h 3 71 s 3h 3 86 s 3h 3 99 dd j 9 and 3 hz 1h 4 19 dd j 9 and 7 hz 1h 4 52 dd j 7 and 3 hz 1h 6 48 d j 12 5 hz 1h 6 55 d j 12 5 hz 1h 6 58 s 2h 7 02 mt 2h 8 13 broad s 1h 8 82 broad s 1h mass spectrum m 542 dci m z 560 mnh 4 base peak m z 543 mh m z 504 mnh 4 t bu m z 443 mh boc 3409 2982 2938 2837 1712 1698 1534 1363 1249 1133 1092 and 851 cm u2212 1 compound 11 61 8 g dissolved in 54 ml of methanol is charged at 20 u00b0 c into a 1 litre three necked flask equipped with a mechanical stirrer a thermometer a t piece a reflux condenser surmounted by a bubble counter and a heating bath and 150 ml of isopropyl acetate 99 ml of a 2 3n solution of hydrochloric acid in methanol and 8 2 ml of distilled water are added the mixture is stirred and heated at 60 u00b0 c for 3 hours the solution cooled to 40 u00b0 c is clarified by filtration through.