Synthesis of 3-Hydroxyisoxazoles from<i>γ</i>-Ketoesters and Hydroxylamine

Sato, Kazuo; Sugai, Soji; Tomita, Kazuo

doi:10.1080/00021369.1986.10867641

Cited by 4 publications

(6 citation statements)

References 2 publications

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“…5-Isopropyl-3-isoxazolol (22c) . Method E: 265 mg, 76%; mp 42−43 °C (lit . mp 41−42 °C); 1 H NMR (CDCl 3 ) δ 1.28 (d, 6H, J = 6.9 Hz), 2.94 (d septet, 1H, J = 6.9 and 0.9 Hz), 5.64 (d, 1H, J = 0.9 Hz), 11.2 (br s, 1H); 13 C NMR (CDCl 3 ) δ 20.3, 27.4, 91.2, 171.1, 179.6; MS(FAB + ) m / z 128 ([M + 1] + , 100).…”

Section: Methodsmentioning

confidence: 99%

“…Whereas ibotenic acid (2) interacts nonselectively with all types of ( S )-glutamate receptors, the analogues ( S )-AMPA (5) and ( S )-homo-AMPA (6) are specific agonists at subtypes of ionotropic and metabotropic ( S )-glutamate receptors, respectively. Other examples of biologically active 3-isoxazolols are 5-methyl-3-isoxazolol (Tachigaren, 7 ) and the phosphorothioate Karphos (8), which are used as a soil fungicide and a broad-spectrum insecticide, respectively 1 …”

Section: Introductionmentioning

confidence: 99%

“…The effects of temperature and pH on the relative amounts of cyclization products have been studied, − but attempts to optimize these parameters in order to maximize the yield of the 3-isoxazolol and, thus, eliminate the formation of 5-isoxazolone 10 have not been successful. Another solution could be a temporary protection of the β-carbonyl as an acetal.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Route to 5-Substituted 3-Isoxazolols. Cyclization of N,O-DiBoc β-Keto Hydroxamic Acids Synthesized via Acyl Meldrum's Acids

Sørensen¹,

Falch²,

Krogsgaard‐Larsen³

2000

J. Org. Chem.

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3-Isoxazolols are most often synthesized from a beta-keto ester and hydroxylamine. This cyclization typically gives rise to a major byproduct, the corresponding 5-isoxazolone. We have found that N, O-diBoc-protected beta-keto hydroxamic acids can be synthesized and cyclized to 5-substituted 3-isoxazolols without formation of any byproduct. We present a novel and versatile three-step procedure in which carboxylic acid derivatives are converted into acyl Meldrum's acids which, upon aminolysis with N, O-bis(tert-butoxycarbonyl)hydroxylamine, lead to the N, O-diBoc-protected beta-keto hydroxamic acids. These hydroxamic acid analogues were then, upon treatment with hydrochloric acid, cyclized to the corresponding 5-substituted 3-isoxazolols.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Novel Route to 5-Substituted 3-Isoxazolols. Cyclization of N,O-DiBoc β-Keto Hydroxamic Acids Synthesized via Acyl Meldrum's Acids

Sørensen¹,

Falch²,

Krogsgaard‐Larsen³

2000

J. Org. Chem.

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“…Karphos are examples of biologically active 3-isooxazolols, which are used as soil fungicides and a broadspectrum insecticide respectively [135]. Incorporation of the 3-isooxazolol moiety into compounds with potential biological activity normally requires cyclisation of β-ketoester with hydroxylamine, which sometime leads to the undesired byproduct.…”

Section: Reviewmentioning

confidence: 99%

Cyclic 1,3‐diones and their derivatives—As versatile reactive intermediates in the syntheses of condensed fused ring heterocyles

Sekhar

2004

Journal of Heterocyclic Chem

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“…Isoxazole derivatives of have been prepared by various reactions, such as acylation, alkylation and halogenation, and shown excellent and durable bioactivity when used as the soil fungicides, systemic insecticides, paddy field herbicides and plant growth regulators 5–22. However, the chemical CRFs of Hymexazol have not been investigated, although there have been a few reports concerning the physical CRFs of Hymexazol with the aim to reduce the danger posed to the environment by the conventional usage 23–25…”

Section: Introductionmentioning

confidence: 99%

Biologically active polymer: controlled‐release formulations based on Hymexazol

Li-min

Liu²,

Shen

et al. 2002

Polymer International

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3‐(2‐Hydroxyethoxy)‐5‐methylisoxazole (2) was prepared by the reaction of 3‐hydroxy‐5‐methylisoxazole (1) with 2‐ethylene chlorohydrin. It reacted with methacryloyl chloride to afford 2‐[3‐(5‐methylisoxazolyl)oxy]ethyl methacrylate (4). The compounds 2 and 4 were confirmed structurally by IR, MASS and 1H NMR spectroscopy and MS. The fungicidal effects of 2 and 4 were investigated. Compound 4 was subjected to radical copolymerization with acrylamide and formed a copolymer 5. It would release the active agent 2 in a reasonable amount by a hydrolysis process. The release rates of the compound 2 were determined by high performance liquid chromatography (HPLC) under different pH conditions. The results indicate that the copolymer 5 is potentially useful for the development of the chemically controlled‐released formulations of Hymexazol. © 2002 Society of Chemical Industry

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Synthesis of 3-Hydroxyisoxazoles fromγ-Ketoesters and Hydroxylamine

Cited by 4 publications

References 2 publications

A Novel Route to 5-Substituted 3-Isoxazolols. Cyclization of N,O-DiBoc β-Keto Hydroxamic Acids Synthesized via Acyl Meldrum's Acids

A Novel Route to 5-Substituted 3-Isoxazolols. Cyclization of N,O-DiBoc β-Keto Hydroxamic Acids Synthesized via Acyl Meldrum's Acids

Cyclic 1,3‐diones and their derivatives—As versatile reactive intermediates in the syntheses of condensed fused ring heterocyles

Biologically active polymer: controlled‐release formulations based on Hymexazol

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