SYNTHESIS OF 6-THIOSIALIC ACIDS

The synthesis of 2-acetamido-2-deoxy-3-thio-D-mannose (11) is describe d. Chain elongation of thiazoline 10 with potassium-di-O-tbutyl-oxaloa cetate yields epimeric 6-thiosialic acids 14 and 15. Chain extension o f 18 with oxaloacetate/Ni++ results in the formation of N-acetyl-6-thi oneuraminic acid (21). Starting from 21 synthesis of alpha-azide 25 an d dehydro-compound 27 was accomplished by treatment of 23 with sodium azide. On the other hand lewis acid catalyzed azidation of 22 beta wit h azidotrimethylsilane afforded beta-azide 29. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.