A Simple One-Pot Synthesis of Functionalized 1,2-Oxazin-6-ones

Abstract

The photooxygenation of furans 1 in the presence of acetaldehyde oxime followed by Et 2 S reduction and SiO 2 treatment leads to 1,2-oxazin-6-ones 4 in good overall yields through a onepot procedure.

Chemistry of Six-Membered Cyclic Oxime Ethers. Application in the Synthesis of Bioactive Compounds

“…Oximes containing a carbonyl group at the γ-position easily cyclize to dihydrooxazines without the formation of side cyclic nitrones of the type 47 (Scheme ). − …”

“…Thus, carboxy-substituted oximes generated from the corresponding keto acids 54 and hydroxylamine can dehydrate to 3-aryl-substituted oxazinones 55 directly upon preparation (Scheme , eq 1), − under the action of sulfuric acid in a catalytic amount or upon treatment with dicyclohexylcarbodiimide. , Methyl esters of unsaturated acids 56 also easily cyclize to 1,2-oxazin-6-ones 57 as well (Scheme , eq 2). , This procedure allows one to synthesize oxazinones 57 from substituted furans 58 …”

Photosensitized Oxidation of Furans. 20.1 A Novel Thermal Rearrangement of Suitably Substituted Alkoxyfuran Endoperoxides via Neighboring-Group Mechanism: Synthesis and Reactivity of the First Functionalized 2-Oxetanyl Hydroperoxides

“…In any case, the driving-force of these conversions is the facile loosening of the C1−O2 bond due to the presence of an ortho ester function in a strained bicyclic structure . The rationale of the mechanisms involved has provided the development of selective synthetic procedures for a large variety of organic compounds, from new peroxidic systems to already known compounds but whose classical approach is difficult or unsuccessful. , …”

“…Within the research work on synthesis and use of organic peroxides, , we have now examined the reaction of singlet oxygen with the hydroxyalkyl-substituted 2-alkoxyfurans 1 purposely prepared to enlarge the synthetic applicability of the related endoperoxides 2 .…”