- The use of K-10/ultrasound in the selective synthesis of unsymmetrical β-enamino ketones
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p-Phenyl substituted β-enamino ketones 2a-p and cyclic β-enamino ketones 4, 6a-f have been prepared by a selective method by dispersing 1,3- diketones and amines on montmorillonite K-10 under sonication.
- Valduga, Claudete J.,Squizani, Adriana,Braibante, Hugo S.,Braibante, Mara E.F.
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p. 1019 - 1022
(2007/10/03)
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- Nonacarbonyldiiron-, Pentacarbonyliron-, or Hexacarbonylmolybdenum-induced Reactions of 4,5-Polymethylene-substituted 2-Isoxazolines
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The reaction of 4,5-polymethylene-substituted 2-isoxazolines, 3-phenyl-3a,5,6,7a-tetrahydro-4H-pyranoisoxazole or 3-phenyl-3a,4,5,6a-tetrahydrofuroisoxazole, with , , or resulted in the formation of 5-hydroxy-1-phenyl-1-pentanone or 4-hydroxy-1-phenyl-1-butanone, via the N-O and C-C bond cleavage of the 2-isoxazoline ring and the subsequent hydrolysis.The similar reaction of 7a-morpholino- and 7a-(1-pyrrolidinyl)-3-phenyl-3a,4,5,6,7,7a-hexahydro-1,2-benzoisoxazoles undergoes the N-O bond cleavage and, the subsequent elimination of the amino group or the C-3a-C-7a bond fission.Although the reaction of 6a-morpholino- and 6a-(1-pyrrolidinyl)-3-phenyl-3a,4,5,6a-tetrahydro-4H-cyclopentisoxazoles with undergoes the N-O bond cleavage, and the subsequent elimination of the amino group or the C-3a-C-6a bond fission, the reaction of those 2-isoxazolines with proceeds very slowly.The mechanisms are proposed for these reactions.
- Nitta, Makoto,Yi, Akihiro,Kobayashi, Tomoshige
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p. 991 - 994
(2007/10/02)
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- Metal-carbonyl-Induced Reaction of Isoxazoles. Ring Cleavage and Reduction by Hexacarbonylmolybdenum, Pentacarbonyliron, or Nonacarbonyldi-iron
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In the presence of and water the isoxazoles (1a-f) undergo thermally induced reductive cleavage of the N-O bond to give β-amino enones in good yield.Similar results were obtained by the use of and water with photoirradiation, or of and water with heating.A mechanism involving an N-complexed isoxazolepentacarbonylmolybdenum or isoxazoletetracarbonyliron, and a - or -complexed (β-oxo vinyl)nitrene intermediate is proposed for the reactions.The complexed nitrene moiety could be reduced by the central metal in the presence of water to give amine.Furthermore, treatment of 2-benzoyl- 3-phenyl-2-H-azirine (8a), which is an isomer of 3,5-diphenylisoxazole, with the metal carbonyls and water also resulted in the formation of a β-amino enone possibly via the corresponding complexed (β-oxo vinyl)nitrene.An N-complexed isoxazole-pentacarbonylmolybdenum intermediate was prepared by the photoreaction of with 3,5-dimethylisoxazole.Its characterization, and chemical transformations, have been carried out to investigate the proposed mechanism.
- Nitta, Makoto,Kobayashi, Tomoshige
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p. 1401 - 1406
(2007/10/02)
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- Reductive Ring Opening of Isoxazoles with Mo(CO)6 and Water
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Reaction of isoxazoles in the presence of Mo(CO)6 and water causes reductive cleavage of the N-O bond to give β-aminoenones in good yields.
- Nitta, Makoto,Kobayashi, Tomoshige
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p. 877 - 878
(2007/10/02)
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