Construction of Diverse N-Heterocycles by Formal (3 + 3) Cycloaddition of Naphthol/Thionaphthol/Naphthylamine and 1,3,5-Triazinanes.

Here, we report a facile and metal-free method for the construction of dihydrooxazine derivatives via a formal (3 + 3) annulation reaction of naphthols and 1,3,5-triazinanes. The 1,3,5-triazinanes were utilized as a formal three-atom synthon (C-N-C) for cycloaddition. In addition, dihydrothiazine and tetrahydrobenzoquinazoline derivatives could also be produced in good yields by this strategy under catalyst-free and additive-free conditions.

Deconstructive Cycloaromatization Strategy toward N,O-Bidentate Ligands from Indolizines and Cyclopropenones.

The innovative construction of novel N,O-bidentate ligands represents a long-standing challenge for chemists. Here, we report an unprecedented approach for the construction of N,O-bidentate derivatives via the merging of ring deconstruction with cycloaromatization of indolizines and cyclopropenones. Without any catalysts, our method can deliver a series of polyaryl 2-(pyridin-2-yl)phenols in excellent yields. In addition, N,O-bidentate organic BF2 complexes can also be constructed via this one-pot protocol.

Visible Light-Induced Cascade Cyclization of 3-Aminoindazoles, Ynals, and Chalcogens: Access to Chalcogen-Containing Pyrimido[1,2-b]-indazoles.

A direct cascade cyclization of 3-aminoindazoles, ynals, and accessible chalcogens facilitated by visible light has been developed. A series of fluoroactive selenium/tellurium-substituted pyrimido[1,2-b]-indazoles were easily accessed in moderate to good yields with a broad scope. Furthermore, we surveyed the spectral properties of selenide pyrimido[1,2-b]-indazoles prepared by this method.

Photoinduced successive oxidative ring-opening and borylation of indolizines with NHC-boranes.

A facile photoinduced successive oxidative ring-opening and borylation of indolizines with NHC-boranes via a one-pot method has been unveiled. This photo-promoted strategy enables the formation of unsaturated NHC-boryl carboxylates under transition metal-free and radical initiator-free conditions. A wide array of pyridine-containing NHC-boryl carboxylates were directly prepared in moderate to good yields. This work contributes to a better understanding of the reactivity and photo-behavior of both indolizines and NHC-boranes.

Optimization of Boron Doped TiO2 as an Efficient Visible Light-Driven Photocatalyst for Organic Dye Degradation With High Reusability.

No visible light activity is the bottle neck for wide application of TiO2, and Boron doping is one of the effective way to broaden the adsorption edge of TiO2. In this study, several Boron doped TiO2 materials were prepared via a facile co-precipitation and calcination process. The B doping amounts were optimized by the degradation of rhodamine B (Rh B) under visible light irradiation, which indicated that when the mass fraction of boron is 6% (denoted as 6B-TiO2), the boron doped TiO2 materials exhibited the highest activity. In order to investigate the enhanced mechanism, the difference between B-doped TiO2 and bare TiO2 including visible light harvesting abilities, separation efficiencies of photo-generated electron-hole pairs, photo-induced electrons generation abilities, photo-induced charges transferring speed were studied and compared in details. h+ and · O 2 - were determined to be the two main responsible active species in the photocatalytic oxidation process. Besides the high degradation efficiency, 6B-TiO2 also exhibited high reusability in the photocatalysis, which could be reused at least 5 cycles with almost no active reduction. The results indicate that 6B-TiO2 has high photocatalytic degradation ability toward organic dye of rhodamine B under visible light irradiation, which is a highly potential photocatalyst to cope with organic pollution.