Organocatalyzed Biginelli Reactions

l-Asparagine–EDTA–amide silica-coated MNPs: a highly efficient and nano-ordered multifunctional core–shell organocatalyst for green synthesis of 3,4-dihydropyrimidin-2(1H)-one compounds

“…Among the various types of nitrogen-containing heterocycles, derivatives of 3,4-dihydropyrimidin-2(1 H )-one, as biologically-active compounds, have found versatile applications such as anti-bacterial, anti-inflammatory, antihypertensive agents, calcium channel blockers and antitumor compounds. 52–60 A simple and general protocol for access to 3,4-dihydropyrimidin-2(1 H )-ones involves the three-component and one-pot Biginelli cyclocondensation of ethyl acetoacetate, urea and various aldehydes accelerated by different types of acidic catalytic systems such as copper( ii ) trifluoromethanesulfonate under microwave irradiation, 61 gallium( iii ) triflate, 62 bismuth pyromanganate nanoparticles, 63 l -proline methyl ester hydrochloride, 64 nanometasilica disulfuric acid, 65 p -toluenesulfonic acid, 66,67 sulfonic acid-supported polymeric catalysts, 68 sulfonated carbons from agro-industrial wastes, 69 phenylboronic acid, 70 1,3-bis(carboxymethyl)imidazolium chloride, 71 sulfonic acid and ionic liquid functionalized covalent organic frameworks, 72 ionic liquid combined with acidic zeolite-supported heteropolyacids, 73 ionic liquid/silica sulfuric acid, 74 bentonite/PS-SO 3 H nanocomposite, 75 dendrimer-attached phosphotungstic acid immobilized on nanosilica under ultrasonication, 76 tungsten-substituted molybdophosphoric acid impregnated with kaolin, 53 zinc- and cadmium-based coordination polymers, 77 metal–organic frameworks (MOFs), 78,79 montmorillonite clay, 80 magnetic nanoparticles, 81 Lewis acidic zirconium( iv )–salophen perfluorooctanesulfonate or sulfated polyborate, 82,83 nanocrystalline CdS thin film, 59 graphene oxide, 84,85 and mesoporous materials. 86,87 Most of the reported methods in this regard demonstrate valuable role of heterogeneous catalysts.…”

Pre-emergence application of (thio)urea analogues compromises the development of the weed species Bidens pilosa, Urochloa brizantha, and Urochloa decumbens

“…Efforts attempting to develop novel, environmentally friendly and more efficient herbicides have increased [19], and as a result, substances that can be degraded by soil microbiota and/or are selective to weed species have become interesting candidates for the mitigation of weed propagation [19]. Biginelli adducts, which are substances obtained from the cyclocondensation of acetoacetic esters, aromatic aldehydes and (thio)urea [20], [21], have the ability to inhibit both cancer cell proliferation and fungal growth and control blood pressure {reviewed by [22], [23]}. Notably, the literature does not describe the potential of Biginelli adducts as herbicides, even though they are structurally related to urea, similar to the widely used herbicide diuron (Fig.…”