Copper-catalyzed aerobic annulation of hydrazones with dienones: an efficient route to pyrazole-linked hybrid molecules

A copper-catalyzed aerobic [3 + 2] annulation reaction to access various pyrazole-bound chalcones starting from readily available and cost-effective hydrazones and dienones is reported. These pyrazole-bound chalcones were further utilized effectively to prepare a series of pyrazole-linked hybrid molecules, such as pyrazole-pyrazoline, pyrazole-aziridine, and pyrazole-pyridine hybrids by efficient simple transformations. Synthetically challenging hybrid molecules were obtained in a simple, two-step process with high atom economy under aerobic copper catalysis.

Modular construction of α-furanyl ketones via semi-pinacol rearrangement-mediated ring expansion

An efficient semi-pinacol rearrangement strategy of enynals involving a metal carbene intermediate has been developed, which allows the practical synthesis of various functionalized α-furanyl ketones in moderate to good yields under mild reaction conditions.

Catalyst- and Additive-Free Approach to Constructing Benzo-oxazine, Benzo-oxazepine, and Benzo-oxazocine: O Atom Transfer and C═O, C-N, and C-O Bond Formation at Room Temperature

An exclusive synthesis of benzo-oxazine, benzo-oxazepine, and benzo-oxazocine from aryl propanal and 2-(hydroxyamino)phenyl alcohol under metal-free conditions is described. O atom transfer and formation of new C═O, C-N, and C-O bonds occur at room temperature to form six-, seven-, and eight-membered heterocycles under one-pot reaction conditions without using an external oxidant and base. The photophysical properties are studied using ultraviolet-visible absorption and photoluminescence. The mechanistic elucidation is well supported by control experiment and literature precedents.

(E)-4-(3-Phenylisoxazol-5-yl)but-3-en-2-one

(E)-4-(3-Phenylisoxazol-5-yl)but-3-en-2-one was synthesized via the oxidative ring opening reaction of 2-(5-methylfuran-2-yl)-1-phenylethanone oxime, followed by the iodine mediated isomerization.

Design of a simple and efficient synthesis for bioactive novel pyrazolyl–isoxazoline hybrids

A simple and new methodology has been developed for the synthesis of novel bioactive pyrazolyl–isoxazoline hybrids using pyrazoline-substituted oxime. Among the hybrid materials, 6m and 6p were found to show the best anti-bacterial and anti-fungal activities.