Bromination of organic substances is still an important reaction in modern synthetic chemistry. In view of the increasing demand for sustainable synthetic chemistry, oxidative bromination can play an important role to avoid the use of hazardous molecular bromine (Br 2 ). In this review, a complete overview of the chemical oxidants will be provided which have been used for the electrophilic as well as radical brominations, starting from less hazardous bromide Br(À I); e. g., HBr or a bromide salt, with a focus on the differences caused by the choice of oxidant.

Water-soluble BOPAHY fluorophores have not yet been reported. The potential of 1,2,3-triazolium salts for the formation of water-soluble chromophores is explored. 1,2,3-Triazole-substituted pyrroles were synthesized in a metal-free pathway and alkylated to obtain water-soluble 1,2,3-triazolium BOPAHY dyes. High fluorescence quantum yields were observed for triazole-bridged BOPAHY dyes in DCM and moderate fluorescence quantum yields for 1,2,3-triazolium-bridged BOPAHY chromophores in DCM and water. The fluorescence of the freely rotatable 1,2,3-triazolium-linked BOPAHYs is partially quenched in water.

Herein, we present the first synthetic methodologies toward non-symmetrical 5,5 ′-C, Clinked bi-1,2,3-triazoles starting from 5-formyl-1,2,3-triazole via two related pathways. In a first reaction, 5-formyl-1,2,3-triazole is successfully reacted with a variety of nitroalkanes and organic azides in a one-pot three-component fashion resulting in tetra-ortho-substituted bi-1,2,3-triazoles. In the second, closely related reaction, 5-formyl-1,2,3-triazole is initially converted with nitromethane to the corresponding nitroalkene, and then subsequently oxidatively cyclized with a number of organic azides toward 4-nitro substituted non-symmetrical tetra-ortho-substituted 5,5 ′-bi-1,2,3-triazoles. The scope of both reactions and furtherr post-functionalizations are examined, and the atropisomeric properties of the obtained bi-1,2,3-triazoles are evaluated.

The Lewis acid mediated Nenitzescu reaction with piperazinone enaminoesters surprisingly afforded rearranged 2-imidazolidinone 5-hydroxybenzofurans. The reaction was optimised and a scope study was performed. A one-pot two-step procedure was realised...

Dihydropyrrolo[1,2-a]pyrazinone rings are a class of heterocycles present in a wide range of bioactive natural products and analogues thereof. As a direct result of their bioactivity, the synthesis of this privileged class of compounds has been extensively studied. This review provides an overview of these synthetic pathways. The literature is covered up until 2020 and is organized according to the specific strategies used to construct the scaffold: fusing a pyrazinone to an existing pyrrole, employing a pyrazinone-first strategy, an array of multicomponent reactions and some miscellaneous reactions.