Synthesis and photocytotoxic activity of [1,2,3]triazolo[4,5-h][1,6]naphthyridines and [1,3]oxazolo[5,4-h][1,6]naphthyridines

Recyclization of 5-Amino- oxazoles as a Route to new Functionalized Heterocycles (Developments of V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the NAS of Ukraine)

The recyclizations of 5-amino- and 5-hydrazine-1,3-oxazoles mainly with electron-withdrawing group in 4th position are considered. The chemical behavior of these heterocycles is due to the presence of two hidden amide fragments; therefore, the recyclization processes include a stage of nucleophile attack on 2nd or 5th position of the oxazole cycle. When the nitrile group is present in 4th position, it is often involved in the recyclization forming α-aminoazoles. 5-Amino/hydrazine-1,3-oxazoles undergo recyclization both in nucleophilic (amines, hydrazine, thionating agents) and electrophilic medium ((trifluoro)acetic acid, other acylating agents). The numerous types of functionalized heterocycles can be easily obtained with the usage of these recyclizations, such as the derivatives of 3-amino-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole, imidazolidine-2,4-dione, 1H-pyrazole-3,4,5-triamine, 5,6-diamino-2,3-diphenylpyrimidin-4(3H)-one, 2-(2-R-7-oxo-5-(trifluoromethyl)oxazolo[5,4-d]pyrimidin-6(7H)-yl)acetic acid, 2-R-4-(5-R'-1,3,4-oxadiazol-2-yl)oxazol-5-amine, (amino(5-amino-1,3,4-thiadiazol-2-yl)methyl)phosphonate.

HSV-1 Glycoprotein D and Its Surface Receptors: Evaluation of Protein-Protein Interaction and Targeting by Triazole-Based Compounds through In Silico Approaches

Protein-protein interactions (PPI) represent attractive targets for drug design. Thus, aiming at a deeper insight into the HSV-1 envelope glycoprotein D (gD), protein-protein docking and dynamic simulations of gD-HVEM and gD-Nectin-1 complexes were performed. The most stable complexes and the pivotal key residues useful for gD to anchor human receptors were identified and used as starting points for a structure-based virtual screening on a library of both synthetic and designed 1,2,3-triazole-based compounds. Their binding properties versus gD interface with HVEM and Nectin-1 along with their structure-activity relationships (SARs) were evaluated. Four [1,2,3]triazolo[4,5-b]pyridines were identified as potential HSV-1 gD inhibitors, for their good theoretical affinity towards all conformations of HSV-1 gD. Overall, this study suggests promising basis for the design of new antiviral agents targeting gD as a valuable strategy to prevent viral attachment and penetration into the host cell.

Evaluation of Fused Pyrrolothiazole Systems as Correctors of Mutant CFTR Protein

Cystic fibrosis (CF) is a genetic disease caused by mutations that impair the function of the CFTR chloride channel. The most frequent mutation, F508del, causes misfolding and premature degradation of CFTR protein. This defect can be overcome with pharmacological agents named “correctors”. So far, at least three different classes of correctors have been identified based on the additive/synergistic effects that are obtained when compounds of different classes are combined together. The development of class 2 correctors has lagged behind that of compounds belonging to the other classes. It was shown that the efficacy of the prototypical class 2 corrector, the bithiazole corr-4a, could be improved by generating conformationally-locked bithiazoles. In the present study, we investigated the effect of tricyclic pyrrolothiazoles as analogues of constrained bithiazoles. Thirty-five compounds were tested using the functional assay based on the halide-sensitive yellow fluorescent protein (HS-YFP) that measured CFTR activity. One compound, having a six atom carbocyle central ring in the tricyclic pyrrolothiazole system and bearing a pivalamide group at the thiazole moiety and a 5-chloro-2-methoxyphenyl carboxamide at the pyrrole ring, significantly increased F508del-CFTR activity. This compound could lead to the synthesis of a novel class of CFTR correctors.

Synthesis and Anticancer Properties of Functionalized 1,6-Naphthyridines

The burgeoning interest in synthesis and biological applications of 1,6-naphthyridines reflects the importance of 1,6-naphthyridines in the synthetic as well as medicinal chemistry fields. Specially, 1,6-naphthyridines are pharmacologically active, with variety of applications such as anticancer, anti-human immunodeficiency virus (HIV), anti-microbial, analgesic, anti-inflammatory and anti-oxidant activities. Although collective recent synthetic developments have paved a path to a wide range of functionalized 1,6-naphthyridines, a complete correlation of synthesis with biological activity remains elusive. The current review focuses on recent synthetic developments from the last decade and a thorough study of the anticancer activity of 1,6-naphthyridines on different cancer cell lines. Anticancer activity has been correlated to 1,6-naphthyridines using the literature on the structure-activity relationship (SAR) along with molecular modeling studies. Exceptionally, at the end of this review, the utility of 1,6-naphthyridines displaying activities other than anticancer has also been included as a glimmering extension.