86260-84-6Relevant articles and documents
Preparation method of 3, 5-disubstituted-4, 5-dihydroisoxazole
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Paragraph 0031; 0082-0087, (2019/12/02)
The invention relates to a preparation method of 3, 5-disubstituted-4, 5-dihydroisoxazole, which comprises the following steps: (1) mixing an aryl-substituted propargyl alcohol compound, a nucleophilic reagent containing nitrogen, oxygen, sulfur or phosph
Metal-carbonyl-induced Reaction of 2-Isoxazolines. Ring Cleavage and Reduction by Pentacarbonyliron or Nonacarbonyldi-iron
Nitta, Makoto,Kobayashi, Tomoshige
, p. 2103 - 2108 (2007/10/02)
3,5-Disubstituted 2-isoxazolines (1a-f) undergo N-O and C-4 - C-5 bond-cleavage reaction with pentacarbonyliron and photoirradiation in methanol to give two fragments (aldehydes and ketones).The ketones could be derived from reduction of the complexed 1-substituted vinylnitrene intermediate and subsequent hydrolysis.Substituent effects have a significant influence on the course of the reaction. 2-Isoxazolines (1h and i) having no substituent at C-5 undergo N-O bond cleavage to give β-hydroxy- and β-methoxy-ketones, in addition to the above mentioned cleavage of the N-O and C-4 - C-5 bonds.Furthermore, 2-isoxazolines (1j and k) bearing a substituent such as an acetoxy or ethoxy group at C-5 undergo N-O bond cleavage, and concomitant elimination of the substituent acetoxy or ethoxy group, leading to β-aminoenones.However, in the case of 2-isoxazolines (1l and m) bearing a piperidin-1-yl group at C-5, the N-O and C-4 - C-5 bond-cleavage reactions predominate over the elimination of the C-5-substituent.Mechanisms are also proposed for the formation of the β-substituted ketones.Similar reactions were also effected thermally for several 2-isoxazolines with nonacarbonyldi-iron.
