NEW EFFECTIVE SYNTHESIS OF )-(1-]4)-MURAMOYL-L-2-AMINOBUTANOYL-D-ISOGLUTAMINE AND -(1-]4)-MURAMOYL-L-2-AMINOBUTANOYL-D-ISOGLUTAMINE, ANALOGS OF GMDP WITH IMMUNOPOTENTIATING ACTIVITY

Ethyl -deoxy-2-phthalimido-1-thio-beta-D-glucopyranoside (5), prepared by benzylation of ethyl -deoxy-2-phthalimido-1-thio-beta-D-glucopyran oside (4), was transformed by reaction with bromine into benzyl-2-deox y-2-phthalimido-beta-D-glucopyranosyl bromide (6). Thioglycoside 5 in the presence of methyl triflate and glycosylbromide 6 in the presence of silver triflate were used as glycosyl donors for condensation with benzyl O-allyl-6-O-benzyl-2-deoxy-alpha-D-glucopyranoside (7), to give benzyl 2-acetamido-3-O-allyl-6-O-benzyl-4-O-(3, -D-glucopyranosyl)-2- deoxy-alpha-D-glucopyranoside (8). Its reductive dephthaloylation with NaBH4/AcOH afforded benzyl anosyl)-6-O-benzyl-2-deoxy-alpha-D-glucopy ranoside (11). Compound 11 was N-acylated to give benzyl -allyl-6-O-be nzyl-2-deoxy-alpha-D-glucopyranosides (12a) or (12b). These compounds were converted into corresponding benzyl 3-O-carboxymethyl-2-deoxy-alp ha-D-glucopyranosides which, by condensation with H-L-Abu-D-isoGln(OBz l) followed by hydrogenolysis of protective benzyl groups, furnished g lycopeptides 16a and 16b. Intramolecular O-->N migration of the allyl protecting group followed by its reduction to the propyl residue by re action of compound 8 with hydrazine or hydrazinium acetate, to give be nzyl anosyl)-6-O-benzyl-2-deoxy-alpha-D-glucopyranoside (9), is also d escribed.