Exploiting silver trifluoromethanesulfonate as efficient and reusable catalyst for the synthesis of dihydropyrimidine derivatives under different reaction environments

Abstract

Different results were generated under different reaction conditions for the multicomponent reactions. Herein, an efficiently improved and mild protocol for the synthesis of dihydropyrimidine derivatives using cheap silver trifluoromethanesulfonate (CF3SO3Ag) as reusable catalyst is explained. With conventional heating and microwave irradiation method, the synthesis of substituted 3,4‐dihydropyrimidine‐2(1H)‐one and 3,4‐dihydropyrimidine‐2(1H)‐thione was achieved in different solvent environments like acetonitrile, water, and under solvent free neat condition. Moreover, the solvents (CH3CN and H2O) containing the CF3SO3Ag were reused for several times without loss of much catalytic activity after separation from the desired products. Thus, the method provides much improved and efficient alternative pathway to the original Biginelli reaction.

The atypical solubility of silver(i) pentafluorobenzoate and its use as a catch-and-release agent

“…Similar recovery and reuse had been previously reported for the closely-related AgOTf salt when it was utilised as a catalyst. 38 Isolation of the liquid substrates could also be envisioned through the same evaporation process, if desired, though was not attempted herein. Subsequent reuse of the recovered 1 with other solvents could then generate new adducts.…”

Synthesis and in vitro study of antiproliferative benzyloxy dihydropyrimidinones

“…White solid (0.315 g, 89%), mp: 200-202°C (lit [25] mp: 173-175°C); White solid (0.318 g, 95%), mp: 188-190°C (lit [3] mp: 187-189°C, lit [26] White solid (0.354 g, 97%), mp: 178-180°C (lit [27] mp: 183-185°C, lit [7] White solid (0.303 g, 77%), mp: 174-176°C (lit [27] White solid (0.392 g, 95%), mp: 210-212°C (lit [28] mp: 218-220°C, lit [29]…”

One-pot synthesis of 1,3,5-triazine-2,4-dithione derivatives via three-component reactions

“…Among multicomponent reactions, aldehydes have emerged as one of the most useful class of molecules. They are quite flexible as possible starting substrates, and through cyclization reactions, can lead to a variety of complex molecules, allowing a wide exploration of scaffolds and substituents diversity [24][25][26][27][28]. In this regard, the use of simple thiourea as an inexpensive thiocarbonyl group source in the multicomponent reaction with aldehydes and other reactive intermediates for the preparation of various triazinethione derivatives by independently varying the individual components thus represents a significant extension in this area.…”