Jaroslav Zajíček

The synthesis of O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1→4)-N-acetylnormuramoyl-l-α-aminobutanoyl-d-isoglutamine☆

Abstract Benzyl 2-acetamido-3- O -allyl-6- O -benzyl-2-deoxy-4- O -(3,4,6-tri- O -acetyl-2-deoxy-2-phthalimido-β- d -glucopyranosyl)- α- d -glucopyranoside ( 4 ) was obtained in high yield on using the silver triflate method in the absence of base. Compound 4 was converted in six steps into benzyl 2-acetamido-4- O -(2-acetamido-3,4,6-tri- O -benzyl-2-deoxy-β- d -glucopyranosyl)-6- O -benzyl-3- O -(carboxymethyl)-2-deoxy-α- d - glucopyranoside, which was coupled with the benzyl ester of l -α-aminobutanoyl- d -isoglutamine and the product hydrogenolyzed to afford the title compound. O -Benzylation of benzyl 2-acetamido-4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-3- O -allyl-6- O -benzyl-2-deoxy-α- d -glucopyranoside with benzyl bromide and barium hydroxide in N,N -dimethylformamide is strongly exhanced by sonication of the reaction mixture.

6-Methyl-5-Azacytidine-Synthesis, Conformational Properties and Biological Activity. A Comparison of Molecular Conformation with 5-Azacytidine

Abstract The title compound was prepared by the isocyanate procedure and the tri-methylsilyl method. The measurement of 1H NMR spectrum of 6-methyl-5-azacytidine (1) revealed a preference of γt (46%) rotamer around C(5′)-C(4′) bond, a predominance of N conformation of the ribose ring (Keq 0.33) and a preference of syn conformation around the C-N glycosyl bond. An analogous measurement of 5-azacytidine has shown a preference of γ+ (60%) rotamer around the C(5′)-C(4′) bond, a predominance of N conformation of the ribose ring (Keq 0.41) and a preference of anti conformation around the C-N glycosyl bond. 6-Methyl-5-azacytidine (1) inhibits the growth of bacteria E. coli to the extent of 85% at 4000 μM concentration and the growth of LoVo/L, a human colon carcinoma cell line, to the extent of 30% at 100 μM concentration but did not inhibit L1210 cells at ≤ 100 μM concentration. 6-Methyl-5-azacytidine (1) exhibited no in vitro antiviral activity at ≤ 1 μM concentration. + Present address: Beckman, 2500 Harbor B...

A new type of functionalized cryptand-like ionophore. Synthesis, structure and complexation

New functionalized cryptand-like ionophores are prepared from appropriate diaza-crown ethers and epichlorohydrin, using FAB MS, potentiometry, 13C-NMR spectroscopy, and T1 relaxation times measurements, the conformation and complexation patterns are found to change dramatically with the change in size of the macrocycle.