4606-54-6Relevant academic research and scientific papers
Synthesis of Natural and Unnatural Quinolones Inhibiting the Growth and Motility of Bacteria
Li, Jianye,Clark, Benjamin R.
, p. 3181 - 3190 (2020/11/03)
Synthesis of a recently discovered S-methylated quinolone natural product (1) was carried out, in addition to the production of a range of 2-substituted 4-quinolone derivatives (2-11). Two approaches were used: (i) the base-catalyzed cyclization of N-(ket
A novel cycloaddition reaction of α-diazo-γ-amido ketones catalyzed by rhodium(II) acetate. Scope and mechanistic details of the process
Pawda, Albert,Price, Alan T.,Zhi, Lin
, p. 2283 - 2292 (2007/10/03)
α-Diazo ketones containing an amido group in the γ-position have been found to underdo a novel rhodium(II)-catalyzed cycloaddition reaction. Intramolecular cyclization of the keto carbenoid onto the oxygen atom of the amide group generates a carbonyl ylide dipole as a transient species. This highly stabilized dipole does not readily undergo 1,3-dipolar cycloaddition but ruther transfers a proton to produce a cyclic ketene N,O-acetal. The ketene acetale is unstable to moisture and upon standing is readily hydrolyzed to a γ-keto-δ-lactone and an amine. In the absence of any significant amount of water, the ketene N,O-acetal undergoes conjugate addition with the activated ?-bond of the dipolarophile to give a zwitterion intermediate. The anionic portion of the zwitterion adds to the neighboring carbonyl group. This is followed by epoxide ring formation with charge dissipation leading to an amido-substituted spiro cyclopentenyl epoxide. In certain cases a hydroxyl lactone was also isolated and its formation can be attributed to the competitive hydrolysis of the zwitterionic intermediate. The Rh(II)-catalyzed reaction of the diazo ketoamide derived from N-benzylpiperidone with DMAD afforded two different types of cyloadducts. In addition to the spiro cyclopentenyl epoxide, a product derived from trapping of the carbonyl ylide dipole was also obtained, thereby providing additional support for the proposed mechanism.
Addition of NN-Dimethylaniline Oxides to Nitrilium Salts and to Dimethyl Acetylenedicarboxylate. Direct Alkylamination of NN-Dimethylanilines
Sheradsky, Tuvia,Nov, Eliahu
, p. 527 - 530 (2007/10/02)
NN-Dimethylaniline oxide (1) and its ring-substituted derivatives react with N-alkylacetonitrilium salts to give the corresponding 2- and 4-(N-alkylacetamido)dimethylanilines.The mechanism, Which involves migration of an amide group from the aniline nitrogen onto the ring, is discussed.Addition of the oxide (1) to dimethyl acetylenedicarboxylate leads either to demethylation of the aniline (main path in dichloromethane) or to a rearrengement, which involves migration of the succinyl moiety onto the ortho-carbon (in ethanol).
