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Biologically interesting 2-aryl-2,3-dihydroquinolin-4(1H)- ones were synthesized using a mild and efficient one-pot procedure starting from o-aminoacetophenones and aromatic aldehydes in the presence of silver(I) triflate. This synthetic protocol provides rapid access to a variety of 2-aryl-2,3-dihydroquinolin-4(1H)-ones. This technique has several advantages, such as the use of easily available starting materials, the efficiency of the catalyst, a simple operation, and tolerance of a wide range of functionality in the aldehydes. Screening of the synthesized compounds for their antioxidant properties revealed that two compounds (with EC50 = 15.42 μM and 15.16 µM) exhibit a potent free-radical scavenging ability towards TEAC free radicals compared to the standard, Trolox. [ABSTRACT FROM AUTHOR]

The direct arylation of C( sp3)H bonds adjacent to oxygen in ethers with phenol and naphthol derivatives was developed via palladium(II) acetate/copper(II) triflate [Pd(OAc)2/Cu(OTf)2]-catalyzed cross-dehydrgenative coupling in the presence of tert-butyl hyroperoxide (TBHP). This process provides exclusive installation of a tetrahydrofuranyl moiety at a more hindered position of multiply substituted phenol derivatives. The cross-dehydrogenative coupling of 1,4-dihydroxynaphthalene with cyclic ethers and free alcohols afforded biologically interesting 2-substituted 1,4-naphthoquinone derivatives. [ABSTRACT FROM AUTHOR]

A new synthetic route for biologically interesting pyranocarbazoles was developed by reaction of 2- or 4-hydroxycarbazole with α,β-unsaturated aldehydes in the presence of ethylenediamine diacetate (EDDA). The key strategy of this methodology is a formal [3+3] cycloaddition via domino aldol-type/6π- electrocyclization. The synthesized pyranocarbazoles can be converted into derivatives bearing substituents on the carbazole and pyran rings. [ABSTRACT FROM AUTHOR]

A facile protocol is developed for the cross-dehydrogenative coupling of ethers and alcohols with phenol and naphthol derivatives. [ABSTRACT FROM AUTHOR]

Chlorin e6 is a well-known photosensitizer used in photodynamic diagnosis and therapy. A method for identifying and purifying a novel process-related impurity during the synthesis of chlorin e6 has been developed. Its structure was elucidated using NMR and HRMS. This new impurity is formed from chlorophyll b rather than chlorophyll a , which is the source of chlorin e6. The intermediates formed during chlorin e6 synthesis were monitored using HPLC-mass spectrometry. This new impurity was identified as rhodin g 7 7 1 -ethyl ester, the structure of which remains unknown to date. The cytotoxic effects of this novel compound in both dark and light conditions were studied against five cancer cell lines (HT29, MIA-PaCa-2, PANC-1, AsPC-1, and B16F10) and a normal cell line (RAW264.7) and compared to those of chlorin e6. Upon irradiation using a laser at 0.5 J/cm 2 , rhodin g 7 7 1 -ethyl ester demonstrated higher cytotoxicity (2-fold) compared to chlorin e6 in the majority of the cancer cell lines. Furthermore, this new compound exhibited higher dark cytotoxicity compared to chlorin e6. Studies on singlet oxygen generation, the accumulation in highly vascular liver tissue, and the production of reactive oxygen species in MIA-PaCa-2 cancer cells via rhodin g 7 7 1 -ethyl ester correspond to its higher cytotoxicity as a newly developed photosensitizer. Therefore, rhodin g 7 7 1 -ethyl ester could be employed as an alternative or complementary agent to chlorin e6 in the photodynamic therapy for treating cancer cells.

Sequential Wolff rearrangement of α-diazo-β-ketoesters followed by trapping of the ketene intermediates with enol ethers generated a variety of γ,δ-unsaturated β-ketoesters. This method involves a novel thermal cascade reaction and allows the synthesis of γ,δ-unsaturated β-ketoesters with trans-stereochemistry under catalyst-free conditions. The synthesized compounds were further transformed into novel 3,5-diketoesters, which were used for the synthesis of naturally occurring 2-pyrone and 1-naphthoic acid ester.