1088-26-2Relevant articles and documents
Assembly of 1,2,3,4-Tetrahydropyrrolo[1,2- a]pyrazines via the Domino Reaction of 2-Imidazolines and Terminal Electron-Deficient Alkynes
Festa, Alexey A.,Golantsov, Nikita E.,Golubenkova, Alexandra S.,Varlamov, Alexey V.,Voskressensky, Leonid G.
, (2022/02/05)
The transformation of 2-imidazolines into 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines has been realized. A pseudo-three-component reaction of 2-imidazolines with terminal electron-deficient alkynes (2 equiv) first generates imidazolidines, containing an N-vinylpropargylamine fragment. The latter can then undergo a base-catalyzed domino aza-Claisen rearrangement/cyclization reaction sequence, simultaneously constructing pyrrole and pyrazine rings. The process works in a broad substrate scope, delivering pyrrolo[1,2-a]pyrazines in good to excellent yields (45-90%). This two-step approach can be carried out in a one-pot fashion without a noticeable decrease in yield. Remarkably, a three-component protocol for the introduction of two different alkynes has been also developed.
Electrophilically activated nitroalkanes in reaction with aliphatic diamines en route to imidazolines
Aksenov, Alexander V.,Aksenov, Nicolai A.,Arutiunov, Nikolai A.,Malyuga, Vladimir V.,Ovcharov, Sergey N.,Rubin, Michael
, p. 39458 - 39465 (2019/12/14)
A novel synthetic methodology for the assembly of imidazolines via an unusual reaction between nitroalkanes and aliphatic 1,2-diamines in the presence of phosphorous acid is described. In contrast to the related highly efficient preparation of benzimidazoles from aromatic amines, this process represents a major synthetic challenge and for a long time was elusive. Analysis of the method limitations is provided.
Copper-catalyzed N -arylation of 2-imidazolines with aryl iodides
Davis, Owen A.,Hughes, Matthew,Bull, James A.
, p. 3470 - 3475 (2013/06/26)
The first copper-catalyzed N-arylation of 2-imidazolines is described. The reaction affords compounds with desirable lead-like characteristics in high yield with practical simplicity under inexpensive, ligand-free conditions. The cross coupling was successful with electron-rich and electron-poor aromatic iodides. Substrates bearing halides, esters, nitriles, and free hydroxyls are well tolerated, providing reactive handles for further functionalization, as are pyridines. In addition, the regioselective N-arylation of a 4-substituted imidazoline is reported.