184423-91-4Relevant academic research and scientific papers
Synthesis of 2,3-dihydro-4(1H)-quinolones and the corresponding 4(1H)-quinolones via low-temperature fries rearrangement of N-arylazetidin-2- ones
Lange, Jens,Bissember, Alex C.,Banwell, Martin G.,Cade, Ian A.
experimental part, p. 454 - 470 (2011/10/09)
N-Arylazetidin-2-ones of the general form 1, which are readily prepared by GoldbergBuchwald-type copper-catalyzed coupling of N-unsubstituted azetidin-2-ones with the relevant aryl halide or using Mitsunobu cyclization processes, undergo smooth Fries-rearrangement in triflic acid at 018°C to give the isomeric 2,3-dihydro-4(1H)-quinolones (2). Dehydrogenation of the latter compounds using 10% Pd on C in 1.0M aqueous sodium hydroxide/propan-2-ol mixtures at ca. 82°C provides the corresponding 4(1H)-quinolones (3).
Stereoselective synthesis of 3-substituted 4-(formyloxy)-2-azetidinones by the unusual Baeyer-Villiger reaction of β-lactam aldehydes. Scope and synthetic applications
Alcaide, Benito,Alyt, Moustafa F.,Sierra, Miguel A.
, p. 8819 - 8825 (2007/10/03)
The Baeyer-Villiger oxidation of 4-formyl-β-lactams 1 with m-CPBA gave 4-(formyloxy) β-lactams 2 in a simple, efficient, and totally stereoselective process. This reaction is one of the scarce examples of the preferred migration of a carbon moiety in an aliphatic aldehyde. The influence of the substituents at N1 and C3 of the four-membered ring in the Baeyer-Villiger rearrangement has been studied. Thus, alkyl, alkenyl, aryl, and alkyloxy 3-substituted-1-(p-anisyl)-2-azetidinones 1 form exclusively 4-(formyloxy) β-lactams 2. Amide or acetoxy substituents at C3 of the four membered ring produce mixtures of 4-(formyloxy) β-lactams 2 and 4-carboxy β-lactams 5. The exclusive formation of carboxy derivatives is observed sometimes for 1-alkyl-substituted-2-azetidinones 1. 4-(Formyloxy) β-lactams 2 are suitable starting materials to prepare different 4-unsubstituted β-lactams 9 using β-hydroxy amides 8 as isolable intermediates. The overall transformation 4-formyl-2-azetidinone to 4-unsubstituted β-lactam is an easy and convenient stereoselective route to these interesting types of compounds.
The unusual Baeyer-Villiger rearrangement of β-lactam aldehdyes: Totally stereoselective entry to cis-3-substituted 4-formyloxy-2-azetidinones
Alcaide,Aly,Sierra
, p. 3401 - 3404 (2007/10/02)
Baeyer-Villiger oxidation of 4-formyl-β-lactams 1 with m-chloroperbenzoic acid in dichloromethane at room temperature is shown to be a convenient method for the preparation of 4-formyloxy-β-lactams 2. Some reactions of novel compounds 2 are also described
