Large scale synthesis of linker-modified sialyl LewisX, LewisX and N-acetyllactosamine

The synthesis of sialyl-Lewis(X) (1b), Lewis(X) (2) and N-acetyllactosamine (3), each being attached to the 1 beta-O-(6-amino)hexyl handle, were scaled up to gram amounts to obtain sufficient material for thorough pharmaceutical evaluations and for derivatizations aiming at more potent selectin antagonists. The disaccharide 3 was synthesised from inexpensive lactose to provide a versatile building block, either to be used for alternative approaches to the Lewis type oligosaccharides, or to prepare polyvalent LacNAc templates to be further elaborated by glycosyltransferase reactions. All syntheses were directed to reasonable large scale procedures, especially by minimising the number of steps and the use of heavy metal salts in glycosylations. (C) 1998 Elsevier Science Ltd. All rights reserved.