A number of non-natural N-acyl derivatives of glucosamine is incubated with a recombinant beta(1-3)galactosyl-transferase and UDP-galactose. Surprisingly, the enzyme recognizes the non-natural accepters as substrates and transfers galactose onto the 3-OH group in a beta-mode to give a series of Lewis(c)-(type 1) disaccharides. (C) 1998 Elsevier Science Ltd. All rights reserved.