2-Alkoxy-3,4-dihydropyrans as modular substrates to construct polyheterocycles by reacting with NH2-containing bisnucleophiles

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

“…A tandem aza‐Henry and intramolecular enamination reaction was believed to be involved in the reaction mechanism. When 1,5‐ or 1,4‐bisnucleophiles were used, the 2‐butoxy‐3,4‐dihydropyran could also be used to synthesize some polyheterocycles under similar conditions …”

A Simple, Efficient, and Eco-Friendly Method for the Preparation of 3-Substituted-2,3-dihydroquinazolin-4(1H)-one Derivatives

“…The dihydroquinazolinone moiety is present in numerous biologically active molecules with various potential therapeutic effects [1,2,3,4,5,6,7,8,9]. In view of the increasingly widespread applications of dihydroquinazolinone derivatives, many researchers have made great effort to develop these types of compounds using different synthetic methodologies [8,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24], such as by using TiO 2 nanoparticles (TiO 2 NPs) as a catalyst for the synthesis of 2,3-disubstituted dihydroquinazolin-4(1 H )-one derivatives [25]; a metal reduction–condensative cyclization strategy [26]; a three-component reaction of isatoic anhydride with amine and 2-formyl benzoic acid in the presence of montmorillonite K10 as a catalyst [27]; ultrasound irradiation catalyzed by dodecylbenzenesulfonic acid [28]; microwave irradiation in the presence of Amberlyst-15 [29] or Cu-CNTs [30]; and condensation of isatoic anhydride, amine, or ammonium salts with aldehydes or ketones in the presence of p -toluenesulfonic acid [31], citric acid [32], or silica bonded with different acids [33,34,35]. Moreover, the development of a simple, efficient, easy method under environmentally benign conditions for the synthesis of 2,3-dihydroquinazolin-4(1 H )-one derivatives is necessary.…”