alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1h)-ones in high yields at 80 °c. our results showed that biginelli reaction not only is ph dependent, but the cation of catalyst plays an important role.

in this study, oxidation of some 3,5-diacyl or 3,5-diester 1,4-dihydropyridines to corresponding pyridine derivatives using sodium bromate in the presence of nh4cl, nahso4 and bu4nhso4 under thermal conditions has been investigated. the yield and structure of formed products is similar under all conditions; however, the reaction is accelerated in the presence of bu4nhso4 and nahso4. in addition...

In this study, oxidation of some 3,5-diacyl or 3,5-diester 1,4-dihydropyridines to corresponding pyridine derivatives using sodium bromate in the presence of NH4Cl, NaHSO4 and Bu4NHSO4 under thermal conditions has been investigated. The yield and structure of formed products is similar under all conditions; however, the reaction is accelerated in the presence of Bu4NHSO4 and NaHSO4. In addition...

Partition behavior of nine small organic compounds and six proteins was examined in poly(ethylene glycol)-8000-sodium sulfate aqueous two-phase systems containing 0.5M osmolyte (sorbitol, sucrose, trehalose, TMAO) and poly(ethylene glycol)-10000-sodium sulfate system, all in 0.01M sodium phosphate buffer, pH 6.8. The differences between the solvent properties of the coexisting phases (solvent d...

A new one-pot, efficient three-component condensation of dimedone, urazole and aromatic aldehydes in the presence of silica supported sodium hydrogen sulfate as an effective heterogeneous catalyst for the synthesis of novel Triazolo[1,2-a]indazole-1,3,8-trione derivatives under solvent-free conditions is described.

An important intermediate phase in the crystallization of aqueous solutions of sodium sulfate is the highly metastable sodium sulfate heptahydrate (Na(2)SO(4).7H(2)O). This has been structurally characterized for the first time by in situ single crystal X-ray diffraction. The crystal structure shows that each sodium cation is octahedrally coordinated to water molecules, with a slight distortion...

An important intermediate phase in the crystallization of aqueous solutions of sodium sulfate is the highly metastable sodium sulfate heptahydrate (Na2SO4 ·7H2O). This has been structurally characterized for the first time by in situ single crystal X-ray diffraction. The crystal structure shows that each sodium cation is octahedrally coordinated to water molecules, with a slight distortion due ...

In this research iron manganese oxide nanocomposites were prepared by co-precipitation, sol-gel and mechanochemical methods by using iron (III) nitrate, iron (II) sulfate and manganese (II) nitrate as starting materials. These nanocomposites were prepared in the presence of various catalyst beds. The polyvinyl pyrrolidon (PVP) was used as a capping agent to control the agglomeration of the nano...