نتایج جستجو برای: 5 tri substituted pyrazoles
تعداد نتایج: 1260756 فیلتر نتایج به سال:
Alkyl-substituted phenolic pyrazoles such as 4-methyl-2-[5-(n-octyl)-1H-pyrazol-3-yl]phenol (L2H) are shown to function as Cu-extractants, having similar strength and selectivity over Fe(iii) to 5-nonylsalicylaldoxime which is a component of the commercially used ACORGA® solvent extraction reagents. Substitution in the phenol ring of the new extractants has a major effect on their strength, e.g...
A series of tri- and tetra- substituted imidazoles were synthesized from benzyl, aldehyde and ammonium acetate in the presence of zeolite as an ecofriendly reusable catalyst under microwave irradiation in the absence of solvent. The yields are high to excellent and the use of microwave irradiation reduces reaction times to few minute.
The monodentate BINOL-derived phosphoramidite PipPhos is used as ligand for the iridium-catalyzed asymmetric hydrogenation of 2and 2,6-substituted quinolines. If tri-ortho-tolylphosphine and/or chloride salts are used as additives enantioselectivities are strongly enhanced up to 89%. NMR indicates that no mixed complexes are formed upon addition of tri-ortho-tolylphosphine.
Several specific synthetic protocols were developed for the preparation from cyanuric chloride of a range of symmetric and non-symmetric di- and tri-substituted 1,3,5-triazines containing alkyl, aromatic, hindered, chiral and achiral hydroxyalkyl, ester and imidazole groups via sequential nucleophilic substitution of the C-Cl bond by C-O, C-N and C-S bonds.
1-Cycloalkyl-2-propene-1-ones were synthesized by electrophilic addition of cycloalkanecarboxylic acid chlorides and its mono- dichloride-substituted derivatives to ethylene in the presence an AlCl3 catalyst at a temperature –10 ÷ –150C dichloroethane medium. The resulting vinyl ketones converted chlorination CCl4 –50C corresponding 1-cycloalkyl-2,3-dichloro-1-propanones, which form 1-R´-3-cycl...
Symmetrically substituted phosphinimino-phos phonium salts [R3PNPR3]X have been known for a long time, and their unusual stability towards acids and bases was demonstrated by the work of Ap pel and Hauss [1], and Schmidbaur and Jonas [2]. The delocalisation of the positive charge in the PNP skeleton and the shielding by the substituents are the main reason for the use of phosphinimino-phos p...
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