Different routes for the construction of biologically active diversely functionalized bicyclo[3.3.1]nonanes: an exploration of new perspectives for anticancer chemotherapeutics.

Cancer is the second most high-morbidity disease throughout the world. From ancient days, natural products have been known to possess several biological activities, and research on natural products is one of the most enticing areas where scientists are engrossed in the extraction of valuable compounds from various plants to isolate many life-saving medicines, along with their other applications. It has been noticed that the bicyclo[3.3.1]nonane moiety is predominant in most biologically active natural products owing to its exceptional characteristics compared to others. Many derivatives of bicyclo[3.3.1]nonane are attractive to researchers for use in asymmetric catalysis or as potent anticancer entities along with their successful applications as ion receptors, metallocycles, and molecular tweezers. Therefore, this review article discusses several miscellaneous synthetic routes for the construction of bicyclo[3.3.1]nonanes and their heteroanalogues in association with the delineation of their anticancer activities with few selective compounds.

Regio- and stereoselective synthesis of a library of bioactive dispiro-oxindolo/acenaphthoquino andrographolides via 1,3-dipolar cycloaddition reaction under microwave irradiation.

Dispiro-pyrrolidino/pyrrolizidino fused oxindoles/acenaphthoquinones have been derived from andrographolide via azomethine ylide cycloaddition to the conjugated double-bond under microwave (MW) irradiation. The reactions are chemo-, stereo-, and regioselective in nature. Change in amino acid from sarcosine/N-benzyl glycine to l-proline changes the regiochemistry. A representative library of 40 compounds along with in vitro anticancer evaluation is reported.

Electrochemically derived redox molecular architecture: a novel electrochemical interface for voltammetric sensing.

Redox-active molecular architectures are electrochemically derived on the electrode surface by Michael addition reaction of o-quinone with surface adsorbed nucleophiles. Electrogenerated o-quinone undergoes facile Michael addition reaction with nucleophile mercaptotriazole (MTz) and mercaptoimidazole (MIm) preassembled on Au electrode. The Michael addition reaction yields redox molecular architectures of 4-(3-mercapto-[1,2,4]triazol-1-yl)-benzene-1,2-diol (MTBD) and 4-(2-mercapto-imidazol-1-yl)-benzene-1,2-diol (MIBD). Solution pH controls the Michael addition reaction; the reaction of o-quinone with MTz nucleophile is more favorable in neutral pH whereas it is favorable in pH >or=9 with MIm. Michael addition of electrogenerated o-quinone with the nucleophile is quantitatively followed in real time using electrochemical quartz crystal microbalance (EQCM). The redox molecular architecture on the electrode surface is characterized by attenuated total reflection (ATR) spectral and electrochemical measurements. ATR spectral measurement confirms the Michael addition with the nucleophile. The redox molecular architecture displays reversible voltammetric response at 0.2 V corresponding to the redox reaction surface confined catechol moiety. The surface coverage of MTBD and MIBD on the electrode surface at pH 7.2 is estimated to be (5.4 +/- 0.2) x 10(-10) and (2.0 +/- 0.2) x 10(-10) mol/cm(2), respectively. Both redox molecular assemblies efficiently mediate the oxidation of reduced nicotinamide adenine dinucleotide (NADH) at a favorable potential. A large decrease in the overpotential associated with an enhancement in the voltammetric peak current with respect to the unmodified electrode is observed. Flow injection amperometric sensing of NADH is performed at the potential of 230 mV. These modified electrodes could detect NADH at micromolar level. Mixed molecular architecture of cysteamine (CYST) and MTz/MIm are developed for the interference free voltammetric sensing of NADH.