30517-58-9Relevant articles and documents
1,2-functionalized imidazoles as palladium ligands: An efficient and robust catalytic system for the fluorine-free Hiyama reaction
Martinez, Regina,Pastor, Isidro M.,Yus, Miguel
supporting information, p. 872 - 877 (2014/03/21)
A variety of hydroxy- and amino-functionalized imidazoles were prepared from 1-methyl- and 1-(diethoxymethyl)imidazole by means of isoprene-mediated lithiation followed by reaction with an electrophile. These compounds in combination with palladium acetate were screened as catalyst systems for the Hiyama reaction under fluorine-free conditions using microwave irradiation. The systematic study of the catalytic system showed 1-methyl-2-aminoalkylimidazole derivative L1 to be the best ligand, which was employed un-der solvent-free conditions with a 1:2 Pd/ligand ratio and TBAB (20 mol-%) as additive. The study has revealed an interaction between the Pd/ligand ratio and the amount of TBAB. The established catalytic system presented a certain degree of robustness, and it has been successfully employed in the coupling of a range of aryl bromides and chlorides with different aryl siloxanes. Furthermore, both reagents were employed in an equimolecular amount, without an excess of organosilane.
Isoprene-catalyzed lithiation of imidazole: Synthesis of 2-(hydroxyalkyl)- and 2-(aminoalkyl)imidazoles
Torregrosa, Rosario,Pastor, Isidro M.,Yus, Miguel
, p. 11148 - 11155 (2007/10/03)
2-Lithioimidazole was prepared by means of a new protocol, which consists of a slight excess of lithium metal in the presence of a substoichiometric amount of isoprene (20 mol%) in THF at room temperature. By reacting this organolithium with carbonyl elec
STUDIES ON THE DILITHIATION OF 1-METHYLIMIDAZOLE. OPTIMISATION OF REACTION CONDITIONS FOR SYNTHESES OF 2,5-DISUBSTITUTED DERIVATIVES
Carpenter, Andrew J.,Chadwick, Derek J.,Ngochindo Raphael I.
, p. 1913 - 1941 (2007/10/02)
Reaction of 1-methylimidazole with an excess of n-butyllithium yields the 2,5-dilithio intermediate.The extent of dilithiation is dependent on the solvent, reaction time, temperature and molar ratio of the lithiating agent to the substrate.Use of a chelating agent for Li(+) decreases the reaction time, temperature and molar excess of the alkyllithium required for high-yielding dilithiation.Syntheses via the dilithio intermediate of 2,5-bis(hydroxydiphenylmethyl)- (3) and 2,5-bis(methylthio)-1-methylimidazole (5), of 1-methyl-5-trimethylsilylimidazole (8), and (in poor yields) of 1-methylimidazole-2,5-dicarboxylic acid (9) and methyl 1-methylimidazole-2,5-dicarboxylate (10) are reported.
