- Structural Investigation of 3,5-Disubstituted Isoxazoles by 1H-Nuclear Magnetic Resonance
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HIV-1 integrase (IN) is a very promising and validated target for the development of therapeutic agents against AIDS. In an effort to design and synthesize biological isosteric analogs of β-diketoacid-containing inhibitors of IN, we prepared a series of s
- Sechi, Mario,Sannia, Luciano,Orecchioni, Maria,Carta, Fabrizio,Paglietti, Giuseppe,Neamati, Nouri
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- Heteropolyacids as green and reusable catalysts for the synthesis of isoxazole derivatives
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Heteropolyanions with different structures, including Keggin, Dawson, Preyssler, mixed addenda, and sandwich types, catalyzed the formation of 1,3-diphenyl-isoxazole from the condensation of 1,3-diphenyl-propane-1,3-dione and hydroxylamine hydrochloride in different solvents and under heating conditions. Our data vividly indicate that H3PW11CuO40 is the catalyst of choice and could catalyze the synthesis of other isoxazole derivatives in high yields and good selectivities. Copyright Taylor & Francis Group, LLC.
- Heravi, Majid M.,Derikvand, Fatemeh,Haeri, Anahita,Oskooie, Hossein A.,Bamoharram, Fatemeh F.
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- Dehydrochlorination of Hydroximoyl Chlorides by the Use of Vinyltins for Synthesis of Isoxazolines (Dihydrooxazoles)
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The reaction of hydroximoyl chlorides and vinyltin compounds afforded isoxazolines via dehydrochlorination and dipolar cycloaddition.
- Moriya, Osamu,Urata, Yoshikiyo,Endo, Takeshi
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- Continuous-flow microliter microwave irradiation in the synthesis of isoxazole derivatives: An optimization procedure
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An efficient method was developed for the synthesis of 3,4,5-trisubstituted and 3,5-disubstituted isoxazoles by using continuous-flow microwave-heated microreactors. A study on the separate effects of the temperature, continuous-flow regime, and microwave irradiation showed that the continuous-flow regime had important effects for less reactive diketones, where microwave heating enhanced the reaction, permitting the formation of 5-methyl-3-phenylisoxazole, which was not formed in the absence of microwaves. Georg Thieme Verlag Stuttgart · New York.
- Rodriguez, Antoniom.,Juan, Alberto,Gomez, M.Victoria,Moreno, Andres,De La Hoz, Antonio
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- Hexacarbonylmolybdenum-induced Reaction of Isoxazoles. Cycloaddition of Isoxazoles with Acetylenic Esters and Related Reactions
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In the presence of hexacarbonylmolybdenum, substituted isoxazoles undergo a cycloaddition reaction with dimethyl acetylenedicarboxylate across the C-4-C-5 bond to give 3,4-bis(methoxycarbonyl)pyridine derivatives.In a similar cycloadition of isoxazoles with methyl propiolate, 4-(methoxycarbonyl)pyridine derivatives were also obtained.The β-carbon atom of methyl propiolate could intervene in the bonding with the C-5 position of the isoxazoles regioselectively.A mechanism involving a complexed 2-oxa-3-azabicyclohepta-3,6-diene derivative and the subsequent N-Oand C-1-C-5 bond cleavage leading to a complexed (β-ketovinyl)nitrene intermediate is proposed for the formation of pyridine derivatives.In order to clarify the mechanistic aspect, the reaction of 4-phenyl-2-oxa-3-azabicyclohepta-3,6-diene and its related compounds were also studied to give pyridine derivatives.
- Kobayashi, Tomoshige,Nitta, Makoto
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- Polystyrene-supported 2-bromoallyl sulfone as an efficient reagent for synthesis of 3,5-disubstituted isoxazoles
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A facile method has been developed for the solid-phase organic synthesis of 3,5-disubstituted isoxazoles from polystyrene-supported 2-bromoallyl sulfone. The advantages of this method include a straightforward and convenient procedure, high product yield,
- Zhang, Liang,Mao, Xue-Chun,Wang, Qiu-Ying,Pan, Yang,Chen, Jun-Min
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- Reaction of 1,3-Bis(het)arylmonothio-1,3-diketones with Sodium Azide: Regioselective Synthesis of 3,5-Bis(het)arylisoxazoles via Intramolecular N-O Bond Formation
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An efficient new synthesis of 3,5-bis(het)arylisoxazoles, involving the reaction of 1,3-bis(het)arylmonothio-1,3-diketones with sodium azide in the presence of IBX catalyst, has been reported. The reaction proceeds at room temperature in high yields and is applicable to a broad range of substrates including the synthesis of 5-methyl-3-arylisoxazoles, a key subunit present in several β-lactamase-resistant antibiotics. A probable mechanism for the formation of isoxazoles has been suggested. A few of the 5-styryl/arylbutadienyl-3-(het)arylisoxazoles have also been synthesized by reacting the corresponding 1-(het)aryl-1-(methylthio)-4-(het)arylidene-but-1-en-3-ones with sodium azide at higher temperatures. The reaction of β-ketodithioesters with sodium azide is shown to furnish β-ketonitriles in good yields.
- Antony P, Mary,Balaji, Gantala L.,Iniyavan, Pethaperumal,Ila, Hiriyakkanavar
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p. 15422 - 15436
(2020/11/30)
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- Asymmetric Aza-Diels-Alder Reactions of in Situ Generated β,β-Disubstituted α,β-Unsaturated N-H Ketimines Catalyzed by Chiral Phosphoric Acids
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A novel asymmetric synthesis of dihydropyridinones with vicinal quaternary stereocenters has been realized by asymmetric aza-Diels-Alder reactions of 3-amido allylic alcohols with oxazolones enabled by chiral phosphoric acid catalysis. A series of aryl/alkyl- and alkyl/alkyl-disubstituted 3-amido allylic tertiary alcohols and 4-substituted oxazolones could be well tolerated in these reactions, producing dihydropyridinones with excellent diastereoselectivities and high enantioselectivities. Mechanistic study and control experiments were performed to shed light on the reaction mechanism, in which a configurationally defined β,β-disubstituted α,β-unsaturated N-H ketimine was proposed as the key intermediate.
- He, Shunlong,Gu, Huanchao,He, Yu-Peng,Yang, Xiaoyu
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supporting information
p. 5633 - 5639
(2020/07/14)
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- AMINOPEPTIDASE A INHIBITORS AND PHARMACEUTICAL COMPOSITIONS COMPRISING THE SAME
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The present invention relates to a novel compound, to a composition comprising the same, to methods for preparing the compound, and the use of this compound in therapy. In particular, the present invention relates to compound that is useful in the treatment and prevention of primary and secondary arterial hypertension, ictus, myocardial ischaemia, cardiac and renal insufficiency, myocardial infarction, peripheral vascular disease, diabetic proteinuria, Syndrome X and glaucoma.
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Page/Page column 56-57
(2020/06/10)
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- Preparation method of isoxazole derivative
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The invention relates to a preparation method of an isoxazole derivative, which comprises the following steps of mixing an propargyl alcohol derivative, a halogen source, an acid and a solvent, and heating to react; adding the hydroxylamine into the react
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Paragraph 0125-0130
(2019/12/02)
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- An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
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α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further, proper functionalization of α-haloketoximes and a change of conditions allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles, thereby realizing a diversity-oriented synthesis.
- Khairnar, Pankaj V.,Lung, Tsai-Hui,Lin, Yi-Jung,Wu, Chi-Yi,Koppolu, Srinivasa Rao,Edukondalu, Athukuri,Karanam, Praneeth,Lin, Wenwei
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supporting information
p. 4219 - 4223
(2019/06/17)
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- Enantioselective Intermolecular Pd-Catalyzed Hydroalkylation of Acyclic 1,3-Dienes with Activated Pronucleophiles
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We report a highly enantioselective Pd-PHOX-catalyzed intermolecular hydroalkylation of acyclic 1,3-dienes. Meldrum's acid derivatives and other activated C-pronucleophiles, such as β-diketones and malononitriles, react with a variety of aryl- and alkyl-substituted dienes in ≤20 h at room temperature. The coupled products, obtained in up to 96% yield and 97.5:2.5 er, are easily transformed into useful chemical building blocks for downstream synthesis.
- Adamson, Nathan J.,Wilbur, Katherine C. E.,Malcolmson, Steven J.
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supporting information
p. 2761 - 2764
(2018/03/06)
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- A handkerchief auspicious past cloth sodium impurities and its preparation method
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The invention discloses a handkerchief auspicious past cloth sodium impurities N - [[3 - (5 - methyl - 4 - phenyl - 3 - isoxazolyl) phenyl] sulfonyl] propionamide and its preparation method, the method is characterized in that the 1 - phenyl - 1, 2 - c diketone as raw materials, after cyclization, sulfonated, aminolysis, bromo, coupling, acylation to obtain handkerchief auspicious past cloth sodium impurities, the invention compounds obtained by 1 H - NMR, 1 H - NMR + D2O, 13 C - NMR spectrum confirmed the structure, preparation method is novel, the obtained compound by HPLC detection, the related substance purity ≥ 98%.
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Paragraph 0035; 0036; 0044
(2018/09/20)
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- Preparation method of parecoxib sodium impurity
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The invention discloses a preparation method of parecoxib sodium impurity 3-[(4- phenyl)-5-methyl-3-isoxazole] benzene sulfonamide. The parecoxib sodium impurity is formed by performing cyclizing, sulfonation, ammonolysis, bromination and coupling on 1-phenyl-1, 2-propanedione serving as a raw material. 1H-NMR, 13C-NMR, DEPT, gCOSY, HMQC and HMBC maps confirm that the structure of the parecoxib sodium impurity, the preparation method is novel, the parecoxib sodium impurity is detected, and the purity of related substance is greater than or equal to 98 percent.
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Paragraph 0009; 0035; 0036; 0042; 0043
(2018/11/03)
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- A direct access to isoxazoles from ynones using trimethylsilyl azide as amino surrogate under metal/catalyst free conditions
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A general method for isoxazoles from readily available ynones using trimethylsilyl azide as an amino surrogate, likely via an unprecedented hydroazidation of the alkyne and denitrogenative cyclization, is demonstrated. The method neither required any cata
- Kumar, Gadi Ranjith,Kumar, Yalla Kiran,Reddy, Maddi Sridhar
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supporting information
p. 6589 - 6592
(2016/06/01)
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- Oxime-mediated facile access to 5-methylisoxazoles and applications in the synthesis of valdecoxib and oxacillin
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A palladium-catalyzed efficient synthesis of 5-methylisoxazoles via oxime-mediated functionalization of unactivated olefins is described. The reaction affords a variety of 5-methylisoxazoles in moderate to good yields. To further demonstrate the utility of the method, the rapid synthesis of valdecoxib and oxacillin is reported. (Chemical Equation Presented).
- Dong, Kui-Yong,Qin, Hai-Tao,Bao, Xing-Xing,Liu, Feng,Zhu, Chen
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p. 5266 - 5268
(2015/01/09)
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- Copper-catalyzed decarboxylation of aromatic carboxylic acids: En route to milder reaction conditions
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The copper-catalyzed decarboxylation of carboxylic aromatic acids has been advantageously achieved by using aliphatic amines like tetramethylethylenediamine (TMEDA) or hexamethylenetetraamine (HMTA) as ligands instead of the aromatic heterocyclic amines (quinoline, phenanthroline) used until now. The improvement is significant since the reaction can be performed at a lower temperature (ca. 50 °C less) and the reaction time is clearly shorter (15 min instead of 12 to 24 h). Copyright
- Cahiez, Gerard,Moyeux, Alban,Gager, Olivier,Poizat, Mael
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supporting information
p. 790 - 796
(2013/04/10)
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- Efficient and regioselective synthesis of 5-hydroxy-2-isoxazolines: Versatile synthons for isoxazoles, β-lactams, and γ-amino alcohols
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"Chemical Equation Presented" An efficient and highly regioselective protocol was developed for the preparation of 5-hydroxy2-isoxazolines, which have been proved to be versatile synthons for isoxazles, β-hydroxy oximes, and γ-amino alcohols. β-Lactams, commonly embedded in the skeletons of bioactive natural products, were also synthesized in two steps from β-hydroxy oximes, providing a new strategy for the synthesis of this kind of compounds.
- Tang, Shibing,He, Jinmei,Sun, Yongquan,He, Liuer,She, Xuegong
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scheme or table
p. 1961 - 1966
(2010/06/20)
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- Efficient and regioselective one-pot synthesis of 3-substituted and 3,5-disubstituted isoxazoles
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(Figure Presented) A series of 3-substituted and 3,5-disubstituted isoxazoles have been efficiently synthesized in moderate to excellent yields by the reaction of N-hydroxyl-4-toluenesulfonamide with α,β-unsaturated aldehydes/ketones. This novel strategy is associated with readily available starting materials, mild conditions, high regioselectivity, and wide scope.
- Tang, Shibing,He, Jinmei,Sun, Yongquan,He, Liuer,She, Xuegong
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supporting information; experimental part
p. 3982 - 3985
(2009/12/03)
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- Copper-catalyzed synthesis of esters from ketones. Alkyl group as a leaving group
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The conversion of ketones to esters has been achieved through the use of Cu catalyst and tetrabutylammonium nitrite. This reaction involves the activation of the less activated C-C bond, and the alkyl group is removed as a leaving group. Various isopropyl ketones are found to be good substrates for this reaction.
- Nakatani, Yuji,Koizumi, Yuichiro,Yamasaki, Ryu,Saito, Shinichi
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supporting information; experimental part
p. 2067 - 2070
(2009/04/08)
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- Reaction of allenylmagnesium and allenylindium bromides with nitrile oxides: synthesis of novel 5-butynyl- and 5-methylisoxazoles
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5-Butynylisoxazoles were obtained in high yields through a domino addition, C-O heterocyclization involving allenylmagnesium bromide and benzonitrile oxide in dry THF, in which the corresponding 5-methylisoxazoles were isolated in trace amounts. However, when the reactions were attempted in aqueous media using allenylindium bromide, 5-methylisoxazoles were formed as the sole products in high yields.
- Sampath Kumar,Singh, Parvinder Pal,Shafi, Syed,Reddy, Pitta Bhaskar,Shravankumar, Kankala,Reddy, Doma Mahender
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p. 887 - 890
(2007/10/03)
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- Preparation of isoxazol(in)yl substituted selenides and their further deselenenylation reaction to synthesize 3,5-disubstituted isoxazoles
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We report a mild 1,3-dipolar cycloaddition protocol for the preparation of 3-aryl-5-phenylselenomethyl isoxazoles and isoxazolines regioselectively. The former was further reacted with LDA and electrophilic substrates followed by selenoxide syn-eliminatio
- Xu, Wei Ming,Tang,Huang, Xian
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p. 501 - 506
(2007/10/03)
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- Dioximes of 1,3-diketones in the trofimov reaction: New 3-substituted pyrroles
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Dioximes of 1,3-diketones enter into the Trofimov reaction forming pyrroles containing an acyl or an O-vinyloxime substituent in position 3 of the pyrrole. In the case of sterically hindered dioximes the main reaction products are isoxazoles. 2005 Springer Science+Business Media, Inc.
- Zaitsev,Schmidt,Mikhaleva,Afonin,Ushakov
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p. 722 - 729
(2007/10/03)
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- The Application of Microreactor Technology for the Synthesis of 1,2-Azoles
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We demonstrate the successful synthesis of an array of 1,2-azoles within a borosilicate glass microreactor whereby conversions in the range of 98-100% were obtained. In terms of large-scale production, this corresponds to 0.339 g day-1 per microreactor when employing reagent concentrations of 1.0 M.
- Wiles, Charlotte,Watts, Paul,Haswell, Stephen J.,Pombo-Villar, Esteban
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- One-Pot Synthesis of 3-Substituted Isoxazoles from Phenyl Vinylic Selenide
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Phenyl vinylic selenide was adopted for 1,3-dipolar cycloaddition to nitrile oxides and subsequent oxidation-elimination furnished 3-substituted isoxazoles with good yields in a one-pot, two-step transformation.
- Sheng, Shou-Ri,Liu, Xiao-Ling,Xu, Qu,Song, Cai-Sheng
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p. 2763 - 2764
(2007/10/03)
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- Utilization of enols of mono- and dicarbonyls compounds in 1,3-dipolar cycloaddition reactions
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2-Isoxazolines were obtained from substituted enols or their ester or ether derivatives in 1,3-dipolar cycloaddition reactions with aliphatic or aromatic nitrile oxides; the effect of the type and number of substituents present at the dipolarophile's double bond on the cycloaddition reaction course - yield, regioselectivity, and possibility of the occurrence of an elimination reaction have been investigated.
- Kurkowska, Joanna,Zadrozna, Irmina
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p. 541 - 554
(2007/10/03)
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- Convenient Approach to 3,4-Diarylisoxazoles Based on the Suzuki Cross-Coupling Reaction
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The Suzuki cross-coupling reaction was found effective for rapid access to a series of 3,4-diarylisoxazoles of pharmacological interest. The efficiency of this approach was demonstrated by the synthesis of the highly potent COX-2-selective inhibitor, 4-(5-methyl-3-phenyl-4-isoxazolyl)benzenesulfonamide (valdecoxib), and its analogues. Thus, the coupling reaction between (3-aryl-5-methyl-4-isoxazolyl)boronic acids, prepared in situ from the corresponding bromides using triisopropyl borate, and aryl bromides containing a 4-sulfonamide or 4-methylsulfonyl group under the standard conditions [Pd(PPh3)4, Na2CO3, EtOH-H2O, reflux] yielded the target 3,4-diarylisoxazoles in good yields.
- Dileep Kumar,Ho, ManKit M.,Leung, Jennifer M.,Toyokuni, Tatsushi
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p. 1146 - 1151
(2007/10/03)
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- Ab initio study of concerted cycloadditions of allene, monofluoroallene, and 1,1-difluoroallene with diazomethane, formonitrile oxide, cyclopentadiene, and furane
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Structures and energetics of reactants and transition structures of cycloadditions of allene (A), monofluoroallene (MFA), and 1,1-difluoroallene (DFA) with diazomethane, formonitrile oxide, cyclopentadiene, and furane have been investigated with the use of ab initio molecular orbital calculations. Structure optimizations were performed with both RHF/3-21G and RHF/6-31G* calculations but were limited to RHF/3-21G for the reactions of cyclopentadiene and furane. For these reactions as well as for the reactions involving DFA electronic energies were computed to the MP3/6-31G* level, whereas the full MP4/6-31G* level was also explored for all the other reactions. Kinetic contributions to activation enthalpies and entropies and solvent effects were also considered. Electronic activation energies are found to be very sensitive to the treatment of electron correlation and fail to converge to values unaffected by further theoretical improvements; indeed, the inclusion of full fourth order correlation (MP4) decreases the activation energies by 5-8 kcal/mol with respect to the preceding level of correlation (MP3). In contrast, the reactivity sequences of A, MFA, and DFA as well as regio and diastereoselectivities attain, in general, stable predictions even at rather low levels of calculation and agree well with experimental trends. The increasing reactivities of A, MFA, and DFA appear to be bound to the decreasing energies requested for the geometry deformation toward their transition structures. As for diastereofacial selectivity in the cycloaddition of MFA, the syn-attack has been found to be strongly favored by the more facile anti- than syn-deformability of the allene moiety, foreshown by a small anti-bending or syn-pyramidalization of the π-atomic orbital of the C2 carbon atom in the structure of the free MFA. Both syn-pyramidalization and the difference of syn/anti-deformability are traceable to the role of vicinal delocalizations between the C2 C2 C3 π-bond (in the free MFA) or the new-forming bonds (in the transition structures) and the allylic C-H and C-F bonds at C1. Differences in vicinal delocalizations are also found to be significant in affecting the regiochemistry of fluoroallenes, even though electrostatic interactions appear to play a major role in this type of selectivity.
- Rastelli, Augusto,Bagatti, Marisa,Gandolfi, Remo
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p. 4965 - 4975
(2007/10/02)
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- The synthesis of isoxazoles from β,γ-acetylenic oximes
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β,γ-Acetylenic oximes (prepared from α-bromooximes) undergo facile conversion to 3,5-disubstituted isoxazoles on mild base treatment.
- Short,Ziegler Jr.
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- Process of preparing pyrazoles, isoxazoles and analogs thereof having activity as 5-lipoxygenase inhibitors
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The present invention is 3,5-substituted, isoxazoles, pyrazoles, isothiazoles, and analogs thereof having 5-lipoxygenase or cyclooxygenase inhibiting activity or as a sunscreen.
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- A Regioselective Synthesis of 3,5-Disubstituted Isoxazoles
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The 3-aryl-5-, and 5-aryl-3-(phenylsulphonylmethyl)isoxazoles (6) and(9) respectively were regioselectively prepared from 1-aryl-3-methylthio-4-phenylsulphonylbut-2-en-1-one (1).As an application of the present method, 3-methyl-5-(4-.pyridyl)isoxazole (2)
- Yokoyama, Masataka,Tsuji, Kouichi,Kushida, Mari
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- Acid-Base Equilibria and Some Transformations of Benzoylacetone Dioxime (BADO) and of o-Hydroxybenzoylacetone Dioxime (HBADO)
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The protolytic equilibrium constants (pK1, pK2, pK3 and pK4) of benzoylacetone dioxime BADO and (pK1, pK2, pK3, pK4 and pK5) of o-hydroxybenzoylacetone diox
- Dzierkacz, Irena M.,Kostka, Krzysztof
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p. 177 - 187
(2007/10/02)
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- REACTIONS OF NITRILE OXIDES WITH PHENYLSULPHINYLPROPA-1,2-DIENE AND 1-PHENYLTHIOPROP-2-ENE. NEW ROUTES TO FUNCTIONALIZED α,β-UNSATURATED KETONE EQUIVALENTS
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Nitrile oxides add regiospecifically to the terminal double bonds in (1) and (3).The adducts (4a-e) were readily cleaved and converted into enone equivalents (8).
- Brown, Roger S.,Eyley, Stephen C.,Parsons, Philip J.
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p. 633 - 642
(2007/10/02)
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- RING TRANSFORMATION REACTION OF 1,4,6-TRISUBSTITUTED 2(1H)-PYRIMIDINONES AND -THIONES WITH HYDROXYLAMINE
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1,4,6-Trisubstituted 2(1H)-pyrimidinones (Ia-e) underwent ring transformation with hydroxylamine to afford 3,5-disubstituted isoxazoles (IIa-e) in high yields.On the other hand, 2(1H)-pyrimidinethiones (IIIa, b, f-k) underwent ring transformation to give mainly a new type of N-substituted 2-aminopyrimidine 1-oxides (IVa, b, f-k) as well as isoxazoles.The reaction of pyrimidinium salts (VII, VIII, and IX) with hydroxylamine is also discussed.Keywords: - ring tranformation reaction; hydroxylamine; nucleophilic reaction; 3,5-disubstituted isoxazoles; N-substituted 2-aminopyrimidine 1-oxides; pyrimidinium salts
- Kashima, Choji,Katoh, Akira,Yokota, Yuko,Omote, Yoshimori
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p. 2516 - 2519
(2007/10/02)
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- Reaction of Substituted 4-Phenylpyrimidine 1,3-Dioxides with Phosphorus Oxychloride
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2-Chloropyrimidine 1-oxides are formed in the reaction of substituted 4-phenylpyrimidine 1,3-dioxides with phosphorus oxychloride; in addtition, 2,4-dichloropyrimidines and 3-phenylisoxazoles were isolated.
- Tikhonov, A. Ya.,Sedova, V. F.,Volodarskii, L. B.,Mamaev, V. P.
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p. 383 - 386
(2007/10/02)
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- Reactions with Organophosphorus Compounds, XLVI. Reactivity Umpolung of 1,3-Dioxo Compounds through Introduction of a Triphenylphosphonio Group. - Regioselective Syntheses of Isoxazoles and Pyrazoles from (2,4-Dioxoalkyl)triphenylphosphonium Salts
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Phosphonium salts 2 and 6, upon deprotonation with BuLi and subsequent reaction with acyl halides, yield the γ-acyl derivatives 3 and 7, respectively, which on treatment with hydrochloric acid afford the corresponding (dioxoalkyl)phosphonium salts 4 and 8.Isoxazole derivatives 9 and 10 are formed regioselectivly from 4 and 8 with NH2OH*HCl, while with R-NH-NH2*HCl (R = H or C6H5) the pyrazole-containing phosphonium salts 14 and 15 are obtained in an analogous reaction.In each case the direction of cyclisation is different to the reactions of the corresponding non-phosphorus substituted 1,3-dioxo compounds.On treatment with aqueous NaOH 9 and 10 are cleaved to triphenylphosphane oxide and isoxazoles 11 and 12, while 14 and 15 yield the pyrazoles 16 and 17.Wittig reaction of 9a or 14a with aldehydes or ketones leads to the isoxazole olefins 13 or the pyrazole olefins 18, respectively.
- Oehler, Elisabeth,Zbiral, Erich
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p. 2852 - 2867
(2007/10/02)
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- Regiospecific Synthesis of Isoxazoles by the Reaction of α-Bromoenones with Hydroxylamine
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In the reaction of α-bromoenones with hydroxylamine, the synthesis of isomeric isoxazoles could be controlled regiospecifically by changing the base.
- Kashima, Choji,Shirai, Shun-ichi,Yoshiwara, Nobutoshi,Omote, Yoshimori
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p. 826 - 827
(2007/10/02)
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