30517-58-9Relevant academic research and scientific papers
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.
1,2-Functionalized Imidazoles as Palladium Ligands: An Efficient and Robust Catalytic System for the Fluorine-Free Hiyama Reaction
Martínez, Regina,Pastor, Isidro M.,Yus, Miguel
supporting information, p. 872 - 877 (2015/10/05)
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 under 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
SYNTHESIS AND APPLICATION OF IMIDAZOLE DERIVATIVES. SYNTHESIS OF (1-METHYL-1H-IMIDAZOL-2-YL)METHANOL DERIVATIVES AND CONVERSION INTO CARBONYL COMPOUNDS
Ohta, Shunsaku,Hayakawa, Satoshi,Nishimura, Kazuko,Okamoto, Masao
, p. 1058 - 1069 (2007/10/02)
(1-methyl-2H-imidazol-2-yl)methanol derivatives ( 4 and 7 ) were prepared by treating carbonyl compounds with 2-lithio-1-methyl-1H-imidazole ( 2 ) or by treating 2-acyl-1H-imidazoles ( 3 ) with organometallic reagents or sodium borohydride.The alcohols ( 4 and 7 ) were convertible into the carbonyl compounds via the corresponding quaternary salts ( 8 and 10 ).The stable (1-methyl-1H-imidazol-2-yl)methanol system, , can be regarded as a masked form of the carbonyl group as well as a synthon of the group.Keywords - (1-methyl-1H-imidazol-2-yl)methanol; 2-acyl-1-methyl-1H-imidazole; carbonyl compound synthesis; β-ketoester; protecting group; latent functionality; symmetric ketone; dihydrojasmone
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.
