Diazo transfer-click reaction route to new, lipophilic teicoplanin and ristocetin aglycon derivatives with high antibacterial and anti-influenza virus activity: an aggregation and receptor binding study. | LitMetric
Semisynthetic, lipophilic ristocetin and teicoplanin derivatives were prepared starting from ristocetin aglycon and teicoplanin psi-aglycon (N-acetyl-D-glucosaminyl aglycoteicoplanin). The terminal amino functions of the aglycons were converted into azido form by triflic azide. Copper catalyzed 1,3-dipolar cycloaddition reaction with lipophilic alkynes resulted in the title compounds. Two of the teicoplanin derivatives showed very good MIC and MBC values against various Gram-positive bacteria, including vanA enterococci. The aggregation and interaction of a n-decyl derivative with bacterial cell wall components was studied. One of the lipophilic ristocetin derivatives displayed favorable anti-influenza virus activity.
Department of Pharmaceutical Chemistry, Medical and Health Science Center, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary. Electronic address:
Despite the close structural similarity between the heptapeptide cores of the glycopeptide antibiotics teicoplanin and ristocetin, synthetically modified derivatives of their aglycons show significantly different antibacterial and antiviral properties. The teicoplanin aglycon derivatives with one exception proved to be potent antibacterials but they did not exhibit anti-influenza virus activity. In contrast, the aglycoristocetin derivatives generally showed high anti-influenza virus activity and possessed moderate antibacterial activity.
Isoindole and benzoisoindole derivatives of ristocetin aglycon have been prepared by reaction with o-phthalaldehyde or naphthalene-2,3-dialdehyde and various thiols. The new compounds exhibited potent antibacterial and anti-influenza virus activity. The cluster forming and fluorescent properties of the aglycon derivatives were also studied.
New sugar derivatives of ristocetin were prepared by copper-catalyzed 1,3-dipolar cycloaddition reaction using azido-ristocetin aglycon and various propargyl glycosides. Some of them were found to be active against gram-positive bacteria and showed favorable antiviral activity against the H1N1 subtype of influenza A virus.
Semisynthetic, lipophilic ristocetin and teicoplanin derivatives were prepared starting from ristocetin aglycon and teicoplanin psi-aglycon (N-acetyl-D-glucosaminyl aglycoteicoplanin). The terminal amino functions of the aglycons were converted into azido form by triflic azide. Copper catalyzed 1,3-dipolar cycloaddition reaction with lipophilic alkynes resulted in the title compounds.
The first total synthesis of the ristocetin aglycon is described employing a modular and highly convergent strategy. An effective 12-step (12% overall) synthesis of the ABCD ring system 3 from its amino acid subunits sequentially features an intramolecular aromatic nucleophilic substitution reaction for formation of the diaryl ether and closure of the 16-membered CD ring system (65%), a respectively diastereoselective (3:1, 86%) Suzuki coupling for installation of the AB biaryl linkage on which the atropisomer stereochemistry can be further thermally adjusted, and an effective macrolactamization (51%) for closure of the 12-membered AB ring system. A similarly effective 13-step (14% overall) synthesis of the 14-membered EFG ring system 4 was implemented employing a room-temperature intermolecular S(N)Ar reaction of an o-fluoronitroaromatic for formation of the FG diaryl ether (69%) and a key macrolactamization (92%) with formation of the amide linking residues 1 and 2.
