17556-67-1Relevant academic research and scientific papers
Microwave-assisted diastereoselective two-step three-component synthesis for rapid access to drug-like libraries of substituted 3-amino-β-lactams
Janssen, Guido V.,van den Heuvel, Joyce A.C.,Megens, Rik P.,Benningshof, Jorg C.J.,Ovaa, Huib
, p. 41 - 49 (2018)
Large, diverse compound libraries are an essential requisite in target-based drug development. In this work, a robust microwave-assisted synthesis for the diastereoselective generation of 3-saccharinyl-trans-β-lactams is reported. The method is optimised
Synthesis and reactivity of trans-2-aryl-3-chloroazetidines
Van Driessche, Berten,Van Brabandt, Willem,D'hooghe, Matthias,Dejaegher, Yves,De Kimpe, Norbert
, p. 6882 - 6892 (2007/10/03)
Several trans-2-aryl-3-chloroazetidines were synthesized in a stereoselective way by reduction of the corresponding β-lactams, which were formed by a Staudinger reaction using different benzaldimines and chloroketene. The resulting chloroazetidines proved to be excellent building blocks for the synthesis of different 3-substituted azetidines through nucleophilic substitution of the chlorine by different carbon, nitrogen, sulfur and oxygen nucleophiles in good to high yields. Since these substitution reactions took place with retention of stereochemistry, the intermediacy of bicyclic azonio[1.1.0]bicyclobutanes is proposed.
Isomerization and deuterium scrambling evidence for a change in the rate-limiting step during imine hydrogenation by Shvo's hydroxycyclopentadienyl ruthenium hydride
Casey, Charles P.,Johnson, Jeffrey B.
, p. 1883 - 1894 (2007/10/03)
Hydroxycyclopentadienyl ruthenium hydride 5 efficiently reduces imines below room temperature. Better donor substituents on nitrogen give rise to faster rates and a shift of the rate-determining step from hydrogen transfer to amine coordination. Reduction of electron-deficient N- benzilidenepentafluoroaniline (8) at 11°C resulted in free amine and kinetic isotope effects of kOH/kOD = 1.61 ± 0.08, k RuH/kRuD = 2.05 ± 0.08, and kRuHOH/ kRuDOD = 3.32 ± 0.14, indicative of rate-limiting concerted hydrogen transfer, a mechanism analogous to that proposed for aldehyde and ketone reduction. Reduction of electron-rich N-alkyl-substituted imine, N-isopropyl-(4-methyl)benzilidene amine (9), was accompanied by facile imine isomerization and scrambling of deuterium labels from reduction with 5-RuDOH into the N-alkyl substituent of both the amine complex and into the recovered imine. Inverse equilibrium isotope effects were observed in the reduction of N-benzilidene-tert-butylamine (11) at -48°C (kOH/kOD = 0.89 ± 0.06, kRuH/kRuD = 0.64 ± 0.05, and kRuHOH/kRuDOD = 0.56 ± 0.05). These results are consistent with a mechanism involving reversible hydrogen transfer followed by rate-limiting amine coordination.
Rearrangement of 2-aryl-3,3-dichloroazetidines: Intermediacy of 2-azetines
Dejaegher, Yves,Mangelinckx, Sven,De Kimpe, Norbert
, p. 2075 - 2081 (2007/10/03)
An easy synthesis of 2-aryl-3,3-dichloroazetidines, a rather unexplored class of azaheterocycles, is described. The title compounds were easily obtained by reduction of the corresponding 4-aryl-3,3-dichloro-2-azetidinones with monochloroalane, which in turn were synthesized by a ketene-imine [2 + 2] cycloaddition. The reactivity of 3,3-dichloroazetidines with bases was investigated, yielding 2-[dimethoxy(aryl)methyl]aziridines by ring contraction when treated with sodium methoxide. Furthermore, reacting the 3,3-dichloroazetidines with sodium hydride in DMSO, followed by aqueous workup, afforded 1-alkyl-2-aroylaziridines, by hydrolysis of the intermediate 2-azetines and ring closure of the transient 3-amino-2-chloro-1-phenyl-1-propanone derivatives. Monitoring this reaction in an NMR tube, using sodium hydride in DMSO-d6, allowed the characterization of the intermediate strained heterocyclic enamines, i.e., 2-azetines, by 1H and 13C NMR.
A Convenient One-Pot Synthesis of 4-Substituted 3,5-Bis(alkoxycarbonyl)-4,5-dihydroisoxazole 2-Oxides from Aldehydes and Nitroacetic Esters in a Solid-Liquid Reaction System and Subsequent Deoxygenation
Melot, Jean-Marie,Texier-Boullet, Francoise,Foucaud, Andre
, p. 558 - 560 (2007/10/02)
4-Substituted 3,5-bis(alkoxycarbonyl)-4,5-dihydroisoxazole 2-oxides are obtained from nitroacetic esters and imines which are prepared from aldehydes and isopropylamine in the presence of molecular sieves.Reduction of the N-oxides with trimethyl phosphite
