no side reactions, and the reaction is complete after 48 h. It was followed by IR spectroscopy by observing the complete disappearance of the azido absorption band at ? = 21 17 cm-' (KBr windows). At the end the resin-bound 8 and 9 were treated with hydrazine hydrate in methanol (1 :7) for about 6 h,ISd-f, ' 7 . 181 which deacetylated all sugar residues to 10 and 11. The cleavage of the synthesized glycopeptides was achieved in 2 h with 95 YO aqueous trifluoroacetic acid (TFA). The N-acetyl glycopeptide amides 12 and 13 were then purified by RP-HPLC and were identical with those prepared along other routes. ['g1 Alternatively, the new procedure can be used in a multiplecolumn or a fully automatic peptide synthesizer." 7 * ' ' ] The multiple column process is preferable when several peptide sequences with few sugar residues are required. For example, besides others the glycopeptides 12 and 13 were synthesized['.
and could be obtained pure in high yields of 77 % and 72 o/o.r211 In a fully automatic peptide synthesizer the complex structure of 14 with five vicinal sugar residues was synthesized. In this case the peptide synthesis was observed photometrically and could be controlled by the disappearance of the yellow color of the Dbht-OH salt.~"~201 In the synthesis of the penta-glycosylated octapeptide, the reduction of the azido groups and the deacetylation of the carbohydrates also was achieved without difficulty, and 14 was isolated pure in yields of 40%.[211 The 'H NMR, FAB-MS, and amino acid analysis data are in accord with the structure.L2'] This example serves to illustrate the power of the new method. Peptides 12, 13, and also 14 are partial structures of the repeating unit of human intestinal m ~c i n , ' ~~] and should be tested for the specificity of the glycosyl transferases.