The synthesis of a 2-amino-2-deoxy-d-glucosyl-muramic acid disaccharide: 2-acetamido-6-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-i,4-di-O-acetyl-2-deoxy- 3-O-[d-i-(methyl carboxylate)ethyl]- α-d-glucopyranose