7 25 7 26 m 1h 7 48 7 52 m 2h 7 60 m 1h 8 22 d j 8 4 hz 1h 10 25 s 1h 13 c nmr cdcl 3 u03b4 29 0 53 3 55 6 112 0 114 2 115 0 120 5 121 7 127 6 127 7 129 7 131 0 132 1 138 3 144 9 148 0 156 6 163 7 ms ei m z 398 m 13 303 10 227 100 hrms ei for c 20 h 18 n 2 o 5 s m calcd 398 0933 found 398 0935 anal c 20 h 18 n 2 o 5 s c h n s the title compound was obtained in 78 yield in a manner similar for the preparation of 20 by use of 2 thenoyl chloride 1 h nmr 400 mhz cdcl 3 u03b4 2 26 t j 7 6 hz 2h 3 83 s 3h 4 03 t j 7 6 hz 2h 6 82 6 87 m 3h 7 12 7 15 m 1h 7 17 t j 7 6 hz 1h 7 49 7 53 m 2h 7 55 dd j 5 2 hz 1 2 hz 1h 7 82 dd j 4 0 1 2 hz 1h 8 22 d j 8 0 hz 1h 10 23 s.