Pyrrolidine-oxadiazolone based organocatalysts are envisaged, synthesized, and utilized for asymmetric Michael reactions. Results of the investigations suggest that some of the catalysts are indeed efficient for stereoselective 1,4-conjugated Michael additions (dr: >97:3, ee up to 99%) in high chemical yields (up to 97%) often in short reaction time. As an extension, one enantiopure Michael adduct has been utilized to synthesize optically active octahydroindole.

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A new bidentate directing group, 3-amino-1-methyl-1 H-pyridin-2-one, is introduced to achieve a powerful Pd metallacycle for selective γ-C(sp)-H activation and arylation of aromatic and aliphatic carboxylic acid derivatives. The versatility of the directing group is validated for remote arylation of β-C(sp)-H, β-C(sp)-H, and γ-C(sp)-H to achieve therapeutically important 2-pyridone analogues and arylated acid synthons. The traceless removal of the directing group to retrieve the directing element and carboxylic acids makes this method more interesting.

Aiming to discover melanin-concentrating hormone receptor 1 (MCHR1) antagonists with improved safety profiles, we hypothesized that the aliphatic amine employed in most antagonists reported to date could be removed if the bicyclic motif of the compound scaffold interacted with Asp123 and/or Tyr272 of MCHR1. We excluded aliphatic amines from our compound designs, with a cutoff value of pK(a) < 8, and explored aliphatic amine-free MCHR1 antagonists in a CNS-oriented chemical space limited by four descriptors (TPSA, ClogP, MW, and HBD count). Screening of novel bicyclic motifs with high intrinsic binding affinity for MCHR1 identified the imidazo[1,2-a]pyridine ring (represented in compounds 6a and 6b), and subsequent cyclization of the central aliphatic amide linkage led to the discovery of a potent, orally bioavailable MCHR1 antagonist 4-[(4-chlorobenzyl)oxy]-1-(2-cyclopropyl-3-methylimidazo[1,2-a]pyridin-6-yl)pyridin-2(1H)-one 10a. It exhibited low potential for hERG inhibition and phospholipidosis induction as well as sufficient brain concentration to exert antiobesity effects in diet-induced obese rats.

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A series of novel bicyclic, substituted pyrimidinone compounds were designed, synthesized and characterized. In vitro antiproliferative activity of the synthesized compounds was evaluated against six different human cancer cell lines using MTT assay. Among all twenty four compounds tested, compound 22 (N-([1,1'-biphenyl]-4-yl)-2-((3-methyl-4-oxo-6,7,8,9-tetrahydro-4Hpyrido[1,2-a]pyrimidin-2-yl)oxy)acetamide) exhibited significant cell growth inhibition of human liver cancer cells HepG2 with GIC 50 (50% growth inhibitory concentration) value of 120 + 10 nM and was found to be selective over healthy human embryonic kidney (HEK) cell line (33.1% inhibition at 20 μM). Further studies demonstrated that compound 22 induced cell apoptosis in HepG2 cells and resulted in similar effect to Staurosporine, a well known proapoptopic compound widely used to induce apoptosis in various cancer cell lines. Compound 22 also rendered acceptable aqueous solubility (3.5 + 0.37 μM, at pH 7.4) and attractive metabolic stability against human liver microsomes with a half-life of 34.63 + 0.33 minutes. Based on the similarity observed between the known tankyrase-1 inhibitors available in literature and compound 22, in silico docking study was performed and the results suggested that the compound interacted with the key amino acid residues present in the tankyrase-1 enzyme active site.

Small molecules containing a 2-pyridone unit received much attention due to their significance in medicinal chemistry. In this regard, development of novel methodologies via metal-catalyzed carbon–carbon bond formation by chelation-assisted C–H activation will be an attractive method to achieve therapeutically important 2-pyridone analogues and arylated acid synthons. We report our studies on a Pd­(II)-catalyzed coupling reaction between methyl, aryl, heteroaryl iodides, and sp2 carbons both at β- and γ-positions using 3-amino-1-methyl-1H-pyridin-2-one as an efficient, built-in bidentate N,O-directing group (DG) toward the synthesis of pyridone derivatives. The effect of temperature, solvent, reagent equivalence, and substrate has been investigated for this DG-mediated late-stage functionalization reactions along with the crystal structure of a selected analogue. Moreover, this DG has been successfully applied for ortho-selective C­(sp2)–H activation in aqueous medium in high yields to demonstrate the practicability of this present methodology.

Reagents that recognize and bind specific genomic sequences in living mammalian cells would have great potential for genetic manipulation, including gene knockout, strain construction, and gene therapy. Triple helix forming oligonucleotides (TFOs) bind specific sequences via the major groove, but pyrimidine motif TFOs are limited by their poor activity under physiological conditions. Base and sugar analogues that overcome many of these limitations have been described. In particular, 2'-O-modifications influence sugar pucker and third strand conformation, and have been important to the development of bioactive TFOs. Here we have analyzed the impact of 2'-O-hydroxyethyl (2'-HE) substitutions, in combination with other 2' modifications. We prepared modified TFOs conjugated to psoralen and measured targeting activity in a gene knockout assay in cultured hamster cells. We find that 2'-HE residues enhance the bioactivity of TFOs containing 2'-O-methyl (2'-OMe) modifications, but reduce the bioactivity of TFOs containing, in addition, 2'-O-aminoethyl (2'-AE) residues.