q c25 13 7 q c30 12 4 q c26 8 6 q c31 this example concerns the preparation of discodermolide tetra acetate having the formula str6 acetylation of discodermolide with acetic anhydride and pyridine at room temperature furnished discodermolide tetra acetate a colorless gum u03b1 25 d 19 2 u00b0 c 0 3 chcl 3 uv u03bb max etoh 235 nm u03b5 12 000 227 sh 21000 222 21400 205 41000 ir chcl 3 3537 3423 2962 1735 1727 1585 1510 1370 1327 1222 1100 1023 965 912 cm 1 1 nmr cdcl 3 u03b4 6 71 1h dddd j 16 6 11 3 10 0 1 3 hz h23 6 03 1h ddd j 10 5 11 3 1 1 hz h22 5 65 1h ddd j 1 8 8 3 10 0 hz h7 5 49 1h dd j 10 7 10 7 hz h9 5 31 1h ddd j 10 5 10 5 1 3 hz h21 5 28 1h ddd j 10 7 10 0 1 0 hz h8 5 21 1h d j 10 0 hz h24 5 15 1h dd j 16 6 1 1 hz h24 4 94 1h d j 9 9 hz h13 4 89 1h dd j 5 8 5 8 hz h3 4 78 1h dd j 5 8.