Formation of isoxazole derivatives via nitrile oxide using ammonium cerium nitrate (CAN): a novel one-pot synthesis of 3-acetyl- and 3-benzoylisoxazole derivatives

Nitroalkanes as key building blocks for the synthesis of heterocyclic derivatives

“…54,60 Reaction of ketones 154 with cerium(IV) ammonium nitrate leads to nitro-ketones 155 that, under the same conditions, produce nitrile oxides, 156 (Scheme 36). 61,62 These 1,3-dipoles react with alkenes to give isoxazolines, 157, and with alkynes to give isoxazoles. Particularly, reaction of intermediate nitrile oxides 156 with the alkynyl glycosides 158 affords the isoxazoles 159, which are stable pharmacophores for glycomimetic syntheses.…”

Cerium(IV) ammonium nitrate for the tandem nitration and oxidative rearrangement of 2-acetyl-1-naphthol benzoylhydrazones into 1,2-diacylnaphthalenes; synthesis of benzo[f]phthalazines

“…1,2 CAN has played a significant role in oxidative cyclisations giving access to various heterocycles, although the synthesis of five-membered rings with two heteroatoms is limited to benzimidazoles, 3 pyrazoles, 4 benzothiazoles 5,6 and isoxazoles. 7 CAN has been reported to cleave semicarbazones to the corresponding aldehydes and ketones 8 but hydrazones are not affected. Furthermore, the reagent has not been used on 2-hydroxyaryl ketone acylhydrazones.…”

“…CAN-mediated transformation of acetone and acetophenone into nitrile oxides, followed by 1,3-dipolar cycloaddition with alkenes and alkynes, is a useful one-pot synthesis of 3-acetyl-and 3-benzoylisoxazole derivatives. 7 However, there have been no reports of isoxazole formation from a hydrazone precursor and CAN.…”

Reaction of olefins using cerium(IV) sulfate tetrahydrate in carbonyl compounds-H2O

“…5,6 Recently, we found several novel reactions using cerium(IV) salts: α-iodination of ketones in acetic acid or alcohols, 7 alkoxyiodination and nitratoiodination of olefins and α,β-unsaturated esters, 8 α,α -diiodination of ketones using iodine-ammonium cerium(IV) nitrate (CAN(IV)), 9 and a novel one-pot synthesis of 3-acetyl-and 3-benzoylisoxazole derivatives using CAN. 10,11 More recently, we reported that the reaction of cycloalkanone, 2-alkylcycloalkanone, and 2-halocycloalkanone with cerium(IV) sulfate tetrahydrate (CS) in alcohols and acetic acid yields the corresponding esters of oxo acids, diesters, oxo acids, and dionic acids. 12 In this paper, we report the reaction of olefins with CS in acetone-H 2 O under reflux for 5 h to give 2-oxo derivatives as major products and 2-oxo-5-hydroxy derivatives as byproducts.…”