A New Substrate for the Biginelli Cyclocondensation:  Direct Preparation of 5-Unsubstituted 3,4-Dihydropyrimidin-2(1H)-ones from a β-Keto Carboxylic Acid

Design and Synthesis of Three Naphtol Derivatives using the Three Component System

“…Finally, the spectrum contains several signals at 6.88, 7.11 and 7.20 ppm for phenyl group; at 7.05, 7.41-7.75 ppm for naphtol group. The 13 ppm for carbons of phenyl group were found. In addition, the presence of 4 was further confirmed from mass spectrum which showed a molecular ion at m/z 292.…”

“…The most widely practiced methodemploys boric acid 10 , silica sulfuric acid 11 , poly(4-vinylpyridine-codivynylbenzene)-Cu(II) complex 11 ,H 2 SO 4 12 , silica triflate 13 and phosphorus pentoxide 14 . Nevertheless,despite its wide scope, the former protocols suffer from several drawbacks e.g.,some reagents have a limited stability and its preparation can be dangerous.Analyzing these data, in this study several straightforward routesare reported for the synthesis of three naphtolderivatives.…”

Synthesis of pyrimidine carboxamide derivatives catalyzed by uranyl nitrate hexa Hydrate with their antibacterial and antioxidant studies

“…Biginelli reaction takes place by mixing different substituted aldehydes, urea or thiourea, and an active 1,3-dicarbonyl compound in combination with different catalytic systems such as AcOH [14], ZrCl 4 [15], Cu(OTf) 2 [16], SiO 2 /H 2 SO 4 [17], La(OTf) 3 [18], CdCl 2 [19], 1-n-butyl-3-methyl imidazolium tetrafluoroborate [20], SiO 2 /NaHSO 4 [21], Pb(NO 3 ) 2 [22], NaCl [23], KSF clay [24], FeCl 3 [25], BiCl 3 [26], ion-exchange resin [27], LiBr [28] [32], Mn(OAc) 3 [33], InBr 3 [ 34], microwave [35][36][37][38] or ultrasound irradiation [39] and solvent-free conditions [40], Co(NO 3 ) 2 .6H 2 O [41], ZnCl 2 /TBAB [42]. In the last two decades microwave mediated reactions have been of great interest in organic synthesis because of their shorter reaction times and high yields of products with good selectivity.…”

Microwave-Assisted Synthesis of Spirofused Heterocycles Using Decatungstodivanadogermanic Heteropoly Acid as a Novel and Reusable Heterogeneous Catalyst under Solvent-Free Conditions

“…Recently, many reviews [8,9] and papers for preparing these compounds have been reported including classical conditions, with microwave and ultrasound irradiation and by using some other different catalysts such as phosphorus pentoxide-methanesulfonic acid [10], potassium terbutoxide (t-BuOK) [11], ammonium dihydrogen phosphate [12], silicagel [13], mesoporous molecular sieve MCM-41 [14], cyanuric chloride [15], nano-BF 3 ⋅SiO 2 [16], silica gel-supported polyphosphoric Acid [17], zirconium(IV) chloride [18], indium(III) bromide [19], ytterbium(III)-resin [20], 1-nbutyl-3-methylimidazolium tetrafluoroborate (BMImBF 4 ) or hexafluorophosphorate (BMImPF 6 ) [21], ceric ammonium nitrate (CAN) [22], Mn(OAc) 3 ⋅2H 2 O [23], lanthanide triflate [24], indium(III) chloride [25], lanthanum chloride [26], H 2 SO 4 [27], montmorillonite KSF [28], polyphosphate ester (PPE) [29], BF3-OEt 2 /CuCl/HOAc [30], and conc. HCl [31,32].…”