4- -3-methyl-5-isoxazolone

Methyl isoxazolone is obtained by reaction between ethyl aceto acetate and nitrous acid... 

Dicarbonylimidazole reacted with the anthranilic acid derivative (498) to produce the fused isoxazolone IV-oxide (499) (77ZOR462). Methyl nitroacetate reacted with indole-3-carbaldehyde to produce (500) (70KGS1505). Treatment of (501) with base gave 3,4,5-triphenyl-2-isoxazoline IV-oxide (Scheme 142) (69JOC984). The reaction was reported to be a direct displacement as (502) did not give a product and no incorporation of deuterium was found using DOMe. 

C-Acetylformamido)-4-isopropyl-3-methyl-4,5-dihydro-5-isoxazolone (55) gave 6-isopropyl-3,5-dimethyl-2 (1 //)-pyrazinone (56) [Lindlar catalyst (Pd/CaC03/trace Pb), H2, EtOH, 20°C, 10 h 90%] also several homologues likewise and in comparable yields.227... 

Although isoxazoles are comparatively weak electron donors, complexes with numerous metal ions, notably metal(II) ions, have been described. The ligands include, besides isoxazole and its methyl and phenyl derivatives, aminoisoxazoles and isoxazolones. An account of the analytical and in-... 

Methylenetiiphenylphosphorane, 307 Methylenomycin A, 183 Methylenomycin B, 184 N-Mcthylephedrine, 308 N-Methyl-i//-ephedrine, 421 Methyl fluorosulfonale, 302, 307 (+)-(S)-4-Methyl-3-heptanone, 17 Methyl 3-hydroxybutyrate, 406 Methyl hydroxymethoxyacetate, 19, 20 Methyl hypobromite, 501 Methyl iodide, 308-309 5-Methylisoxazole, 309 3-Methyl-5(4/0-isoxazolone, 309 Methyl jasmonate, 92, 358 Methylketene methyl trimethylsilyl acetal, 310... 

The next category of f)-diketones are 4-acyl-l-phenyl-3-methyl-5-pyrazolones (see Eigure 2.5) and their analogs of 3-phenyl-4-acyl-5-isoxazolones (see Eigure 2.6). The latter type of P-diketones have stronger acidities (lower pA a values) than the former, and have recently been smdied as promising light conversion molecular devices [46-51]. 

Deng, B. L., Hartman, T. L., Buckheit, R. W, Jr, Pannecouque, C., De Clercq, E., Cushman, M. Replacement of the metabolically labile methyl esters in the alkenyldiarylmethane series of non-nucl-eoside reverse transcriptase inhibitors with isoxazolone, isoxazole, oxazolone, or cyano substituents. J. Med. Chem. 2006, 49(17), 5316-5323. 

Structure 159 has been erroneously assigned to the product of the reaction between 3-benzoyl-3-methyl-47/-isoxazol-5-one 157 and SOCI2 (53GA192). In reality, the compound has the structure of isoxazolone 158 (74HCA1934). The reactions of chloro compound 158 with ammonia, phenylenediamine, and phenylhydrazine produce enamine 160, isoxazolo[5,4-e]1.4-diazepine 161, and isoxazolo[5,4-c]pyrazole 162, respectively (59ZOB3446). The formation of 161 and 162 represents examples of substitution at the keto group in position 5 (Scheme 71). 

It is rather toxic to mammals, its acute oral lDj being for rats 126 mg/kg. Its vapour causes lung irritation. The 4-(3-chlorophenylhydrazono)-3-methyl-5-isoxazolone analogue, which is considerably less toxic to mammals, has therefore been synthesised. The acute oral lDj of metazoxolon (71) for femal rats is 3340 mg/kg, its dermal toxicity is higher than 1000 mg/kg (Purnell, 1973). 

Hydrazino-5,6-diphenyl-l,2,4-triazine (289) reacts with 4-benzylidene-2-phenyl-5(4//)-oxazo-lones (290) and 4-benzylidene-3-methyl-5(4//)-isoxazolones (291) in toluene to products (292), (293) substituted in the hydrazino group, the first by acylation by the oxazolone, the second by arylraethylidene group transfer (Scheme 53) <88JHC1813>. 

A Haloform-type reaction occurs between trichloromethyl-substituted 1,3-diketones and hydrazine or. N-methylhydroxylamine to afford hydroxypyrazoles (e.g., 26) and 2-methyl-3-isoxazolones, respectively.6... 

Drazoxolon. 3-Methyi-4.[ 2-chlorophenyI)hydra-zone)-4,5-isoxazoiedioite 4-(2-chlorophenylhydrazono)-3-methyl-5(4H)-lsoxazolone 3-methyl-4-(o-ch]orophenyihy-drazono) -5 -isoxazolone PP 781 Ganocide Mil-Col Saisan. 

Caswell No. 207C 4-(2-Chlorophenylhydra2one)-3-methyl-5-isoxazolone 4-((o-Chlorophenyl)hydra2ono)-3-methyl-2-isoxazolin-... 

Chlorophenylhydrazone)-3-methyl-5-isoxazolone 4-(2-Chlorophenylhydrazone)-3-methyl-5(4H)-isoxazolone 4-(2-Chlorophenylhydrazono)-3-methylisoxaxol-5-one. See Drazoxolon... 

Methyl-4-(o-chlorophenylhydrazono)-5-isoxazolone 3-Methyl-4,5-isoxaxoledione-4-((2-chloropenyl) hydrazone)... 

DBN and (dichloromethyl)benzene added to a soln. of 4-benzyl-3-methyl-A -5-isoxazolone in acetonitrile, and refluxed for 5 h - product. Y 72%. F.e. and from the corresponding N-sodio-isoxazolone with NEt3 s. E.M. Beccalli et al.. Synthesis 1988, 630-1. 

Hydrazine sulfate added to a cooled soln. of Na in ethanol, stirred 0.5 hr. at room temp., 4-benzoyl-3-methyl-5-isoxazolone added, and refluxed 32 hrs. 4-benzoyl-3-methyl-5-pyrazolone. Y 54%. F. e., also with phenylhydrazine, s. H. Wamhoff, D. Schramm, and F. Korte, Synthesis 1971, 216. 

Flash pyrolysis of 4-arylmethylidene-3-methyl-5(4//)-isoxazolones (127) yields phenylacetylenes with alkoxy, chloro, dimethylamino and hydroxy substituents. The reaction proceeds via an arylmethylidene carbene as has been described for a... 

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