SYNTHESIS OF A FULLY PROTECTED GLYCOOCTAOSYL SERINE ISOLATED FROM BLOOD-GROUP-A HUMAN OVARIAN MUCIN

-tri-O-acetyl-2-deoxy-alpha-D-galactopyranosyl)-(1 --> )-O-[(2,3,4-tri -O-benzyl-alpha-L-fucopyranosyl)-(1 --> 2)]-O-(4,6-di-O-acetyl-beta-D- galactopyranosyl)-(1 --> 3)-O-(3,6-di-O-benzyl-2-deoxy- 2-phthalimido- beta-D-glucopyranosyl)-(1 --> -tri-O-acetyl-2-deoxy-alpha-D-galactopyr anosyl)-(1 --> )-O-[(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-(1 --> 2)]-O-(4,6-di-O-acetyl-beta-D-galactopyranosyl)-(1 --> ]-2-acetamido-2 -deoxy-alpha-D-galactopyranosyl}-(1 --> 3)-L-serine allyl ester, a pro tected glycosylserine identified as a blood group A mucin-type determi nant, was synthesized for the first time in an efficient and stereocon trolled manner. Ethyl 6-tri-O-acetyl-2-deoxy-alpha-O-galactopyranosyl- (1 --> )-O-[(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-(1 --> 2)]-O-(4 ,6-di-O-acetyl-beta-D-galactopyranosyl)-(1 --> -deoxy-2-phthalimido-1- thio-beta-D-glucopyranoside and ,4,6-tri-O-acetyl-2-deoxy-alpha-D-gala ctopyranosyl -(1 --> )-O-[(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-( 1 --> 2)]-O-(4,6-di-O-acetyl-beta-D-galactopyranosyl)-(1 --> )-2-aceta mido-2-deoxy-alpha-D-galaclopyranosyl}-(1 --> 3)-L-serine allyl ester were the key intermediates for the crucial glycosylation to afford the title compound.