Elaboration of a proprietary thymidylate kinase inhibitor motif towards anti-tuberculosis agents

International audienceWe report the design and synthesis of a series of non-nucleoside MtbTMPK inhibitors (1-14) based on the gram-positive bacterial TMPK inhibitor hit compound 1. A practical synthesis was developed to access these analogues. Several compounds show promising MtbTMPK inhibitory potency and allow the establishment of a structure-activity relationship, which is helpful for further optimization

The design and synthesis of inhibitors of Mycobacterium tuberculosis thymidylate kinase (MtTMPK)

Thymidylate kinase (TMPK) phosphorylates thymidine 5’-monophosphate (dTMP) and has been proposed as an attractive target for Mycobacterium tuberculosis (Mt).1 By mimicking the structure of the substrate (dTMP), we have previously discovered different series of nucleoside analogues with MtTMPK inhibitory activities in a micromole range.2 Based on recently reported potent piperidin-3-yl-thymine inhibitors of Gram-positive bacterial TMPK,3 we report a series of isomeric N-benzyl-substituted piperidin-4-yl-thymine analogues, some of which demonstrate potent Mt TMPK inhibitory activity. Towards this end a convenient and high-yield synthesis was developed to access 1-substitued thymine derivatives

Penetration enhancing effect of phytoceramides

Ceramides are essential components in the stratum corneum barrier function. Different classes of ceramides are present in human skin, differing in the nature of sphingosine and acyl moieties with respect to chain length, degree of saturation and the presence of an OH group [1]. Ceramides with a saturated sphingosine base containing a hydroxyl function at C4 are known as phytoceramides. A few studies demonstrated the penetration enhancing properties of ceramides [2-5], however, systematic studies using phytoceramides are lacking. This led us to assess the penetration enhancing effect of phytosphingosine and a series of nine phytoceramides via transdermal experiments using in vitro Franz diffusion cells. As transdermal model compounds, testosterone, caffeine and ibuprofen were tested in a 50:50 (V/V) EtOH:H2O dose formulation [6]. Results showed that the penetration enhancing effect of the phytoceramides depends on the used model compound. Selected phytoceramides exhibited a penetration enhancing ratio of more than two. References [1] Janůšová, B.; Zbytovská, J.; Lorenc, P.; Vavrysová, H.; Palát K.; Hrabálek, A.; Vávrová, K. (2011). Effect of ceramide acyl chain length on skin permeability and thermotropic phase behavior of model stratum corneum lipid membranes. Biochimica et Biophysica, 1811, 129–137. [2] Vávrová, K.; Hrabálek, A.; Dolezal, P.; Holas, T.; Zbytovská, J. (2003). L-serine and glycine based ceramide analogues as transdermal permeation enhancers: polar head size and hydrogen bonding. Bioorganic & medicinal chemistry letters, 13, 2351-2353. [3] Vávrová, K.; Zbytovská, J.; Hrabálek, A. (2005). Amphiphilic transdermal permeation enhancers: structure-activity relationships. Current Medicinal Chemistry, 12, 2273-2291. [4] Novotý, J.; Janůšová, B.; Novotý, M.; Hrabálek, A.; Vávrová, K. (2009). Short-chain ceramides decrease skin barrier properties. Skin pharmacology and Physiology, 22, 22-30. [5] Sinko, B.; Kökösi, J.; Avdeef, A.; Takács-Novák, K. (2009). A PAMPA study of the permeability-enhancing effect of new ceramide analogues. Chemistry & Biodiversity, 6, 1867-1874. [6] Baert, B.; Deconinck, E.; Van Gele, M.; Slodicka, M.; Stoppie, P.; Bode, S.; Slegers, G.; Vander Heyden, Y.; Lambert, J.; Beetens, J.; De Spiegeleer, B. (2007). Transdermal penetration behaviour of drugs: CART-clustering, QSPR and selection of model compounds. Bioorganic & medicinal chemistry, 15(22), 6943-6955

Synthetic fosmidomycin analogues with altered chelating moieties do not inhibit 1-deoxy-D-xylulose 5-phosphate reductoisomerase or Plasmodium falciparum growth in vitro

Fourteen new fosmidomycin analogues with altered metal chelating groups were prepared and evaluated for inhibition of E. coli Dxr, M. tuberculosis Dxr and the growth of P. falciparum K1 in human erythrocytes. None of the synthesized compounds showed activity against either enzyme or the Plasmodia. This study further underlines the importance of the hydroxamate functionality and illustrates that identifying effective alternative bidentate ligands for this target enzyme is challenging