Travaux plus anciens ...
Trisubstitution of pyridine through sequential and regioselective palladium cross-coupling reactions affording analogs of known GPR54 antagonists
RSC Advances, 2013,3, 10296-10300
Because of their large spectrum of applications, poly-functionalized pyridines remain an attractive challenge in modern organic chemistry. We describe the poly-functionalization of halopyridines through a series of sequential and regioselective palladium-catalyzed cross-coupling reactions (Suzuki–Miyaura, Sonogashira and Buchwald–Hartwig reactions). This strategy was applied to the synthesis of several analogs of single non-peptidic known GPR54 antagonists.
N-Heteroarylation of Chiral α-Aminoesters by Means of Palladium-Catalyzed Buchwald–Hartwig Reaction
Journal Of Organic Chemistry, 2013,78(16), 7930-7937
N-Heteroaryl-α-amino acid derivatives are valuable pharmacological agents as peptidomimetics. Classical SNAr methods using acid catalysis and elevated temperatures could not be extended to various α-amino acids and fairly electrophilic heterocyclic partners. Here, we report a mild and versatile method of N-heteroarylation of chiral α-aminoesters without racemization, involving Buchwald–Hartwig conditions. It could be extended to various α-amino acids and azines. This efficient N-heteroarylation leads to (i) a chemical library of putative peptidomimetics combining diverse azaheterocycles with the chiral α-aminoesters and their corresponding derivatives (amides, alcohols, etc.) and (ii) arginine derivatives designed as NPFF receptor ligands.
Palladium-Catalyzed Synthesis of Substituted Pyrido[2,3-d]pyridazines at Positions 5 and 8
Synthesis-Stuttgart 2012, 44, 3216-3224
Several synthetic strategies were developed for the preparation of highly substituted pyrido[2,3-d]pyridazines. We particularly focused on the impact of the pyridine nitrogen atom on pyridazine ring reactivity toward aromatic substitutions, alkylations, or pallado-catalyzed cross-coupling reactions.
![Graphical abstract : Palladium-Catalyzed Synthesis of Substituted Pyrido[2,3-d]pyridazines at Positions 5 and 8](uploads/RTEmagicC_Ibrahim_Synthesis_2012.gif.gif)
Direct Guanidinylation of Aryl and Heteroaryl Halides via Copper-Catalyzed Cross-Coupling Reaction
Journal of Organic Chemistry 2012, 77, 417-423
A modified Ullmann reaction using p-methoxybenzyl (PMB) guanidine as guanidinylation agent yielded various aryl and heteroaryl guanidines in good yields.
6-endo-dig Cyclization of heteroarylesters to alkynes promoted by Lewis acid catalyst in the presence of Bronsted acid
Tetrahedron Letters 2008, 49, 62-65
We report a regiocontrolled 6-endo-dig cyclization of 2-(2-arylethynyl)heteroaryl esters occurred under Brønsted acidic conditions and in the presence of a catalytic amount of Lewis acids such as Cu(OTf)2, AuCl3, or (CF3CO2)Ag. A variety of heterocyclic lactones are readily prepared in excellent yields.
