benzofurans and aniline

A copper-catalyzed annulative amination approach to 3-aminobenzofurans and -indoles from o-alkynylphenols and -anilines has been developed. The Cu-based catalysis is based on an umpolung, electrophilic amination with O-benzoyl hydroxylamines and enables the mild and convergent synthesis of various 3-aminobenzoheteroles of biological and pharmaceutical interest. Some mechanistic investigations and an application of this protocol to construction of more complex tricyclic framework are also described.

Topics: Amination; Aniline Compounds; Benzofurans; Catalysis; Copper; Heterocyclic Compounds, 3-Ring; Indoles; Molecular Structure

Ample evidence supports the critical role of oxidized low-density lipoprotein (ox-LDL) in initiation and progression of atherosclerosis. Oxidation of LDL is a complex process involving several steps (processes) of reactions such as initiation and propagation. Both proteins and lipids in LDL undergo free radical-mediated oxidations leading to the formation of ox-LDL that plays a pivotal role in atherosclerosis. Antioxidants of various types (both aqueous and lipophilic) either arrest or retard the oxidation of LDL at various steps of the oxidation process (e.g., initiation or propagation). Certain lipophilic antioxidants act as the chain-terminating antioxidants leading to the inhibition of LDL oxidation. The current chapter describes the designing and efficacy of two novel lipophilic antioxidants (benzofuranol, BO-653 and aniline, BO-313) in inhibiting the LDL oxidation and atherogenesis in experimental animal model. Furthermore, the characteristics of an effective antioxidant to inhibit LDL oxidation and atherogenesis which dictates the designing of the antioxidant drug and its mechanism(s) of antiatherogenic action are discussed.

Topics: Aniline Compounds; Animals; Antioxidants; Atherosclerosis; Benzofurans; Copper; Disease Models, Animal; Drug Design; Female; Lipoproteins, LDL; Male; Molecular Structure; Oxidation-Reduction; Rabbits; Thiobarbituric Acid Reactive Substances

The effect of temperature on the fluorescence intensity of 4-(5-methyl-3-furan-2-yl-benzofuran-2-yl)-7-methyl-chromen-2-one (MFBMC) in different solvents, has been studied in the temperature range 293-333K. A mechanism of fluorescence quenching with increase in temperature is discussed in terms of the relative location of lowest (1)(pipi*) and (3)(npi*) states, and the energy difference between them. The non-radiative deactivation of excited state in the absence of quencher is temperature-dependent; its activation energy has been found to be 9.453-27.893kJmole(-1). Further, the fluorescence quenching by aniline was investigated by both steady-state and time-resolved measurement (at 296K). The quenching is found to be appreciable and shows positive deviation in the Stern-Volmer plots. This could be explained by static-dynamic quenching models. Various rate constants of the bimolecular quenching reaction have been determined by using ground-state complex formation and sphere of action static quenching model. The magnitude of these constants suggests that sphere of action static quenching model agrees very well with experimental results. Further, with the use of finite sink approximation model, it is concluded that the quenching mechanism is diffusion-limited.

Topics: Absorption; Aniline Compounds; Benzofurans; Chromones; Fluorescence; Kinetics; Solvents; Spectrometry, Fluorescence; Temperature; Time Factors

Zn(OTf)2 (10 mol %) catalyzed the cyclization of propargyl alcohols with PhXH (X = O, NH) in hot toluene (100 degrees C) without additive and gave indole and benzofuran products with different structures. In such transformations, alpha-carbonyl intermediates A and C were isolated as reaction intermediates. The 1,2-nitrogen shift in the formation of indole is catalyzed by Zn(OTf)2, and its mechanism has been elucidated. This catalytic cyclization is also applicable to the synthesis of oxazoles through the cyclization of propargyl alcohols and amides without a 1,2-nitrogen shift.

Topics: Alcohols; Amides; Aniline Compounds; Benzofurans; Catalysis; Cyclization; Indoles; Mesylates; Molecular Structure; Oxazoles; Phenols; Stereoisomerism