Large scale Biginelli reaction via water-based biphasic media: a green chemistry strategy

Vinte anos de química verde: conquistas e desafios

“…14,[26][27][28][29][30][31][32][33][34][35][36] Os temas cobertos por essas revistas incluem desde a síntese orgânica, reações orgânicas, química de produtos naturais, estudos de mecanismo de reação até os diferentes aspectos da espectroscopia. Pesquisas nessas áreas são particularmente importantes para a indústria farmacêutica, pois a obtenção do produto desejado é frequentemente acompanhada de grandes quantidades de resíduos (Fator E muito elevado, ou seja, a maior parte dos átomos dos reagentes são incorporados aos resíduos).…”

Multicomponent hot-water synthesis of 7-unsubstituted 4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidines and their antimicrobial and antifungal activity

“…Recently the investigation of organic reactions in water gained some impact. Latest reviews 2,3 and monographs 4,5 showed that use of water as a reaction medium can be useful for carrying out very different kinds of organic reactions; among them are aldol reaction 5 and Knoevenagel reaction 6 , which is especially important because these reactions could be key steps in the multicomponent synthesis of six-membered heterocycles, such as pyridines 7 and pyrimidines 8 . Although the limited The purity and structures of compounds 4a-h were confirmed by their elemental analysis and spectral data ( H NMR spectra of all the compounds synthesized showed signals for 6-H methylene protons at 4.79 -4.95 ppm, broad singlet for NH protons of dihydropyrimidine ring at 10.40 -10.84 ppm and sharp singlet for 2-H proton of triazole moiety at 7.68-7.71 ppm (for 4a-c,e,f) and other signals for terminal substituents.…”

A Green, Expeditious, One-Pot Synthesis of 3, 4-Dihydropyrimidin-2(1H)-ones Using a Mixture of Phosphorus Pentoxide-Methanesulfonic Acid at Ambient Temperature

“…The literature survey reveals that numerous methods have been developed for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones by three-component cyclocondensation of aldehyde, urea, and ethylacetoacetate, which comprises the use of ionic liquids [18], microwave irradiation [19], ultrasound irradiation [20], BF 3 ·OEt 2 [21], NiCl 2 ·6H 2 O and FeCl 3 ·6H 2 O [22], CoCl 2 ·6H 2 O [23], BiCl 3 [24], InCl 3 [25], and InBr 3 [26]. Zn(OTf) 2 [27], Cu(OTf) 2 [28], Bi(OTf) 3 [29], p-TSA [30], silica sulphuric acid [31], potassium hydrogen sulphate [32], formic acid [33], chloroacetic acid [34], chlorosulfonic acid [35], P 2 O 5 /SiO 2 [36], TFA [37], CF 3 COONH 4 [38], p-TSA in biphasic media [39], ZnCl 2 [40], and I 2 [41]. …”