Cu(I)-catalyzed alkyne–azide ‘click’ cycloaddition (CuAAC): a clean, efficient, and mild synthesis of new 1,4-disubstituted 1H-1,2,3-triazole-linked 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile–crystal structure

Versatile Synthetic Platform for 1,2,3-Triazole Chemistry

1,2,3-Triazole scaffolds are not obtained in nature, but they are still intensely investigated by synthetic chemists in various fields due to their excellent properties and green synthetic routes. This review will provide a library of all synthetic routes used in the past 21 years to synthesize 1,2,3-triazoles and their derivatives using various metal catalysts (such as Cu, Ni, Ru, Ir, Rh, Pd, Au, Ag, Zn, and Sm), organocatalysts, metal-free as well as solvent- and catalyst-free neat syntheses, along with their mechanistic cycles, recyclability studies, solvent systems, and reaction condition effects on regioselectivity. Constant developments indicate that 1,2,3-triazoles will help lead to future organic synthesis and are useful for creating molecular libraries of various functionalized 1,2,3-triazoles.

Loading of g-C3 N4 on Core-Shell Magnetic Mesoporous Silica Nanospheres as a Solid Base Catalyst for the Green Synthesis of some Chromene Derivatives under Different Conditions

Using heterogeneous basic catalysts has a great importance in chemical reactions because of their advantages (such as easy separation and thermal stability at harsh conditions) over homogeneous catalysts. In this study, magnetic mesoporous silica nanoparticles (mSiO₂) containing graphitic carbon nitride layers (mSiO₂/g‐C₃N₄(x)) were fabricated through a facile process (x signifies the amount of melamine applied during synthesis). Graphitic carbon nitride layers were decorated on mSiO₂ by calcination of immobilized melamine (as graphitic carbon nitride precursor) on mSiO₂ in the last step of catalyst synthesis. The structure of the prepared catalysts was confirmed using XRD, BET, FESEM, EDX, elemental mapping and TEM methods. The catalytic efficiency of the so‐obtained solid base composite was investigated for the synthesis of some dihydropyranochromenes and spiro‐dihydropyranochromenes under thermal and microwave conditions. Using mSiO₂/g‐C₃N₄(x) led to high yields under green conditions and in short reaction times and without a decrease in catalytic activity after four consecutive cycles.