2H-Pyrano[3,2-c]chromene-2,5(6H)-diones: Synthesis, Characterization, Photophysical and Redox Studies for Potential Optoelectronic Applications.

Herein, we report the preparation of 2H-pyrano[3,2-c]chromene-2,5(6H)-diones 3a-x by reacting 4-hydroxycoumarins 1a-b with Baylis-Hillman adducts 2a-w having electron releasing or electron withdrawing groups on benzyl ring of the pyranochromene moiety and study of their photophysical properties. The study of optical and electrochemical properties of the prepared compounds reveals that the electron releasing and electron withdrawing groups has not much impact on ground and excited state electronic behavior on pyranochromene moiety. The density functional theory suggests the highest occupied molecular orbital and lowest unoccupied molecular orbitals spread on coumarin moiety of pyranochromene unit.

Direct Access for the Regio- and Stereoselective Synthesis of -Alkenylpyrazoles and Chromenopyrazoles.

A highly regio- and stereoselective method was developed for the preparation of -alkenylpyrazoles and chromenopyrazoles by the reaction of -tosylhydrazones and salicyl -tosylhydrazones with alkynes under neat conditions in the presence of La(OTf). The present study was found to be efficient and convenient for direct access to -alkenylpyrazoles and chromenopyrazoles through C-C, C-N, and C-O bond forming reactions. Structure assignment of -alkenylpyrazole compound was confirmed by X-ray analysis.

Synthesis and anti-inflammatory activity of 2-oxo-2H-chromenyl and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates.

Cycloaddition reaction of 4-chloro-2-oxo-2H-chromene-3-carbaldehydes (3a-g) and 4-chloro-2H-chromene-3-carbaldehydes (7a-h) with activated alkynes (4a-b) provided the 2-oxo-2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (5a-n) and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (8a-p). All the prepared compounds were screened for anti-inflammatory activity. In vitro anti-inflammatory activity data demonstrated that the compounds 5g, 5i, 5k-l and 8f are effective among the tested compounds against TNF-α (1.

Stereospecific Synthesis of 3,4-Dihydro-2-naphtho-1,4-oxazin-2-ones by Unification of Benzoxepine-4-carboxylates with Chiral Amino Acid Ethyl Esters.

A novel and efficient stereocontrolled method has been developed for the preparation of chiral 3,4-dihydro-2-naphtho[1,2-][1,4]oxazin-2-ones by the reaction of benzoxepine-4-carboxylates with chiral amino acid ethyl esters for the first time. The chiral 3,4-dihydro-2-naphtho-1,4-oxazinones have been achieved in one step by the formation of C-N, C-C, and C-O bonds.

A facile construction of oxygen heterocycles by the reaction of benzoxepine-4-carboxylates with dihaloalkanes and activated alkynes.

This manuscript describes the preparation of heterocyclic compounds such as naphtho[1,3]-dioxoles (3a-h), [1,4]-dioxines (4a-h), [1,4]-dioxepines (5a-c), [1,4]-dioxocines (6a-c) and diethyl 2-(2-ethoxy-2-oxoethyl)naphtho[1,3]dioxoles (8a-f). These heterocyclic compounds have been achieved by the reaction of benzoxepine-4-carboxylates (1a-h) with dihaloalkanes (2a-e) and activated alkyne (7a) for the first time. This work represents the first example for the construction of utile oxygen heterocycles by the formation of C-C and C-O bonds in a one step process.