141241-06-7Relevant academic research and scientific papers
Lewis acid catalyzed dipolar cycloadditions of an activated imidate
Bowman, Roy K.,Johnson, Jeffrey S.
, p. 8537 - 8540 (2007/10/03)
An evaluation of simple Lewis acids revealed that N-malonylimidates undergo catalyzed [3+2] cycloaddition reactions with aldehydes, imines, and activated olefins to form oxazolines, imidazolines, and pyrrolines, respectively. Reactions proceed optimally at ambient temperature with the addition of 5 mol % of MgCl2 in CH3CN. Experiments aimed at elucidation of the reactive intermediate undergoing cycloaddition suggest that the Lewis acid promotes a 1,2-prototropic shift to give a metal-coordinated azomethine ylide, rather than ionization and proton transfer to give a nitrile ylide.
A new route to 2-oxazolines, bis-oxazolines, and 2-Imidazoline-5-ones from imidates using solvent-free cycloadditions: Synthesis, chemical properties, and PM3 MO calculations
Lerestif, Jean Michel,Toupet, Loic,Sinbandhit, Sourisak,Tonnard, Francois,Bazureau, Jean Pierre,Hamelin, Jack
, p. 6351 - 6364 (2007/10/03)
The 1,3-dipolar cycloadditions between imidate 1, derived from dimethylaminomalonate and aldehydes 2(a-f), phthalaldehyde 2g, isophthalaldehyde 2h. 4-chlorophenylisocyanate 9a, ethoxycarbonylisothiocyanate 9d as dipolarophiles proceeds regioselectively in
Synthesis of functionalized phenylalanine derivatives by ring opening reactions of 3-arylaziridine-2-carboxylic esters
Legters, Johan,Thijs, Lambertus,Zwanenburg, Binne
, p. 16 - 21 (2007/10/02)
Ring-opening reactions of 3-arylaziridine-2-carboxylic esters with various nucleophiles are described.Racemic methyl 3-(4-methoxyphenyl)-, 3-phenyl- and 3-(4-nitrophenyl)aziridine-2-carboxylate (1a, 1b and 1c, respectively) were selected as substrates.In the absence of acid, no ring opening occurred.On treatment with ethereal hydrogen chloride, 1a gave a mixture of diastereomers 2a, whereas 1b and 1c gave mixtures of regioisomers 2b/3b and 2c/3c, respectively.Boron-trifluoride etherate catalyzed reaction of 1a with benzenethiol and indole also resulted in the formation of diastereomeric ring-opened products 4a and 6a, respectively, due to the electron-releasing properties of the p-methoxy group.Only C3 attack was observed.Under the same conditions, 1b and 1c gave a clean SN2-type ring opening, leading to diastereomerically pure products 4b, 4c, 6b and 6c.Reaction of 1b with acetic acid gave 7 in an SN2-type ring opening at C3, followed by an O->N acyl shift.Treatment of enantiopure (+)-(2S,3R)-1b with benzenethiol, indole and acetic acid gave the corresponding enantiomerically pure β-functionalized α-amino acid derivatives.Functionalization of 1b at nitrogen strongly increased the reactivity: N-acylaziridine 8 isomerized to trans-oxazoline 11 when treated with boron trifluoride etherate in acetonitrile.
