1. Synthesis and immunoadjuvant activities of 2-acetamido-5-O-acetyl-6-O-acyl-2-deoxy-3-O-[(R)-2-propionyl-L-alanyl-D- isoglutamine]-D-glucofuranoses as potential prodrug forms of 6-O-Acyl Derivatives of N-acetylmuramyl dipeptide
P L Durette, C P Dorn Jr, A Friedman, A Schlabach J Med Chem. 1982 Sep;25(9):1028-33. doi: 10.1021/jm00351a005.
2-Acetamido-5-O-acetyl-6-O-acyl-2-deoxy-3-O-[(R)-2-propionyl-L-alanyl-D- isoglutamine]-D-glucofuranoses, designed as prodrug forms of the corresponding immunoadjuvant-active 6-O-acyl derivatives of N-acetylmuramyl dipeptide (MDP), were synthesized from benzyl 2-acetamido-2-deoxy-5, 6-O-isopropylidene-beta-D-glucofuranoside and found, when administered to mice in an aqueous medium, to elevate antibody production against bovine serum albumin. The 5,6-di-O-acetyl derivative 8 exhibited activity similar to that of MDP at 50 micrograms/dose. The antibody titer measured for the 5-O-acetyl-6-O-stearoyl compound 9 was comparable to that obtained with 6-O-stearoyl-MDP at 50 micrograms, and both compounds were more active than MDP at 5 micrograms. The more lipophilic 5-O-acetyl-6-O-[2-(behenoyloxy)isobutyryl] compound 10 was considerably more active than MDP at both 50 and 5 micrograms; moreover, its potent adjuvant activity was not diminished at the lower dose. The three 5-O-acetylated 6-O-acylated dipeptidyl furanose derivatives also significantly stimulated production of circulating antibodies against hepatitis B vaccine in mice; titers were comparable to those observed with the alum-adsorbed vaccine. The range of immunoadjuvant activities obtained with 8-10 and control compounds supports a prodrug mechanism for this class of furanoid MDP analogues.
2. Synthesis and biological activities of N-acetyl-1-thiomuramoyl-L-alanyl-D-isoglutamine and some of its lipophilic derivatives
A Hasegawa, Y Hioki, M Kiso, H Okumura, I Azuma Carbohydr Res. 1983 Nov 25;123(2):183-99. doi: 10.1016/0008-6215(83)88476-6.
N-Acetyl-1-thiomuramoyl-L-alanyl-D-isoglutamine and some lipophilic analogs were synthesized from benzyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[D-1-(methoxycarbonyl)ethyl ]- alpha-D-glucopyranoside (1). O-Debenzoylation of 2, derived from 1 by oxidation, gave 2-acetamido-2-deoxy-4,6-O-isopropylidene-3-O-[D-1-(methoxycarbonyl)ethyl ]-D-glucopyranose (3). Condensation of the alkoxy-tris(dimethylamino)phosphonium chloride (4), formed from 3 by the action of carbon tetrachloride and tris(dimethylamino)phosphine, with potassium thioacetate afforded 2-acetamido-1-S-acetyl-2-deoxy-4,6-O-isopropylidene-3-O-[ D-1-(methoxycarbonyl)ethyl]-1-thio-beta-D-glucopyranose (8). Coupling of the acid 9, obtained from 8 by hydrolysis and subsequent S-acetylation, with the methyl ester of L-alanyl-D-isoglutamine gave N-[2-O-(2-acetamido-1-S-acetyl-2,3-dideoxy-4,6-O- isopropylidene-1-thio-beta-D-glucopyranose-3-yl)-D-lactoyl]-L-alan yl-D- isoglutamine methyl ester (10), which was converted, via O-deisopropylidenation, S-deacetylation, and de-esterification, into the N-acetyl-1-thiomuramoyl dipeptide. Condensation of 11 (derived from 10 by S-deacetylation) and of 12 (obtained from 10 by S-deacetylation and de-esterification) with various acyl chlorides yielded the corresponding 1-S-acyl-N-acetylmuramoyl-L-alanyl-D-isoglutamine derivatives, which were converted into the desired, lipophilic 1-thiomuramoyl dipeptides by cleavage of the isopropylidene group. Condensation of 11 with the alkyl bromides yielded the 1-S-alkyl derivatives, which were also converted, via O-deisopropylidenation and de-esterification, into the corresponding 1-S-alkylmuramoyl dipeptides. The biological activities were examined in guinea-pigs and mice.
3. Synthesis and reactions of O-acetylated benzyl alpha-glycosides of 6-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-N-acetylmuramoyl-L- alanyl-D-isoglutamine esters: the base-catalysed isoglutamine in equilibrium glutamine rearrangement in peptidoglycan-related structures
D Keglević, A E Derome Carbohydr Res. 1989 Feb 15;186(1):63-75. doi: 10.1016/0008-6215(89)84005-4.
Condensation of benzyl 2-acetamido-6-O-(2-acetamido-3,4,6-tri-O-acetyl-2- deoxy-3-O-[(R)-1-carboxyethyl]-alpha-D-glucopyranoside (2) and its 4-acetate (4) with L-alanyl-D-isoglutamine benzyl ester via the mixed anhydride method yielded N-(2-O-[benzyl 2-acetamido-6-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D- glucopyranosyl)-2,3-dideoxy-alpha-D-glucopyranosid-3-yl]-(R)-lacto yl)-L- alanyl-D-isoglutamine benzyl ester (5) and its 4-acetate (6), respectively. Condensation by the dicyclohexylcarbodi-imide-N-hydroxysuccinimide method converted 2 into benzyl 2-acetamido-6-O-(2-acetamido-3,4,6-tri-O-acetyl- 2-deoxy-beta-D-glucopyranosyl)-3-O-[(R)-1-carboxyethyl]-2-deoxy-alpha-D- glucopyranoside 1',4-lactone (7). In the presence of activating agents, 7 underwent aminolysis with the dipeptide ester to give 5. Zemplén O-deacetylation of 5 and 6 led to transesterification and alpha----gamma transamidation of the isoglutaminyl residue to give N-(2-O-[benzyl 2-acetamido-6-O-(2- acetamido-2-deoxy-beta-D-glucopyranosyl)-2,3-dideoxy-alpha-D-glucopyr anosid-3- yl]-(R)-lactoyl)-L-alanyl-D-isoglutamine methyl ester (8) and -glutamine methyl ester (9). Treatment of 6 with MgO-methanol caused deacetylation at the GlcNAc residue to give a mixture of N-(2-O-[benzyl 2-acetamido-6-O-(2-acetamido-2- deoxy-beta-D-glucopyranosyl)-4-O-acetyl-2,3-dideoxy-alpha-D-glucopyra nosid-3- yl]-(R)-lactoyl)-L-alanyl-D-isoglutamine methyl ester (11) and -glutamine methyl ester (12). Benzyl or methyl ester-protection of peptidoglycan-related structures is not compatible with any of the reactions requiring alkaline media. Condensation of 2 with L-alanyl-D-isoglutamine tert-butyl ester gave N-(2-O-[benzyl 2-acetamido- 6-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)-2,3-d ideoxy- alpha-D-glucopyranosid-3-yl]-(R)-lactoyl-L-alanyl-D-isoglutamine tert-butyl ester (16), deacetylation of which, under Zemplén conditions, proceeded without side-reactions to afford N-(2-O-[benzyl 2-acetamido-6-O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-2,3-dideoxy-alpha-D-glucopyranosid-3-yl]-(R)-la cotyl)-L- alanyl-D-isoglutamine tert-butyl ester (17).
