Application of α-Amino-β-fluorophosphonates in Construction of their Dipeptide Analogues

Herein, we present application of α-amino-β-fluorophosphonates for the construction of their dipeptide analogues. α-Amino-β-fluorophosphonates were prepared in a XtalFluor-E mediated deoxyfluorination of α-hydroxy-β-aminophosphonates. The reaction proceeds through an aziridinium ion formation, which was confirmed by the formation­ of a hexacoordinate phosphorus compound. Moreover, the absolute configuration of the obtained compounds was determined by X-ray analysis, which proved the stereochemistry.

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

Herein, we present an efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates. Each step of the synthesis was optimized to provide excellent yields. Moreover, the absolute configuration of the obtained compounds was determined by X-ray analysis, which proved the stereochemistry that was proposed based on NMR studies.

Design, synthesis and biological evaluation of immunostimulating mannosylated desmuramyl peptides

Muramyl dipeptide is the minimal structure of peptidoglycan with adjuvant properties. Replacement of the N-acetylmuramyl moiety and increase of lipophilicity are important approaches in the preparation of muramyl dipeptide analogues with improved pharmacological properties. Mannose receptors present on immunocompetent cells are pattern-recognition receptors and by mannose ligands binding they affect the immune system. Here we present the design, synthesis and biological evaluation of novel mannosylated desmuramyl peptide derivatives. Mannose was coupled to dipeptides containing a lipophilic adamantane on N- or C-terminus through a glycolyl or hydroxyisobutyryl linker. Adjuvant activities of synthesized compounds were investigated in the mouse model using ovalbumin as an antigen. Their activities were compared to the previously described mannosylated adamantane-containing desmuramyl peptide and peptidoglycan monomer. Tested compounds exhibited adjuvant activity and the strongest enhancement of IgG production was stimulated by compound 21 (Man-OCH2-ᴅ-(1-Ad)Gly-ʟ-Ala-ᴅ-isoGln).

Design, synthesis and biological evaluation of immunostimulating mannosylated desmuramyl peptides

Muramyl dipeptide is the minimal structure of peptidoglycan with adjuvant properties. Replacement of the N-acetylmuramyl moiety and increase of lipophilicity are important approaches in the preparation of muramyl dipeptide analogues with improved pharmacological properties. Mannose receptors present on immunocompetent cells are pattern-recognition receptors and by mannose ligands binding they affect the immune system. Here we present design, synthesis and biological evaluation of novel mannosylated desmuramyl peptide derivatives. Mannose was coupled to dipeptide containing lipophilic adamantane on N- or C-terminus through glycolyl or hydroxyisobutyryl linker. Adjuvant activities of synthesized compounds were investigated in the mouse model using ovalbumin as an antigen. Their activities were compared to the previously described mannosylated adamantane-containing desmuramyl peptide and peptidoglycan monomer. Tested compounds exhibited adjuvant activity and the strongest enhancement of IgG production was stimulated by the compound 21 (Man-OCH2-D-(1-Ad)Gly-L-Ala-D-isoGln).

Advances in Desmuramyl Peptide Research

Immune adjuvants are added to vaccines in order to enhance the immune response to an antigen. Muramyl dipeptide, N-acetylmuramyl-L-alanyl-D-isoglutamine, is the smallest structural unit of peptidoglycans showing the immunostimulating activity. Muramyl dipeptide analogues without the hydrophilic N-acetylmuramyl moiety are called desmuramyl peptides. Here, we provide review of desmuramyl peptides which were synthesized in order to improve the pharmacological properties of parent muramyl dipeptide, including our results regarding adamantane containing derivatives. Approach for future design of novel immunostimulators based on multiple pathogen recognition receptor activation was also considered.