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Journal articles on the topic 'Isoxazoles'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Fuse, Shinichiro, Taiki Morita, and Hiroyuki Nakamura. "Step-by-Step Multifunctionalization of Isoxazoles Based On SEAr Reactions and C–H Direct Arylations." Synthesis 49, no. 11 (April 18, 2017): 2351–60. http://dx.doi.org/10.1055/s-0036-1588784.

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Functionalized isoxazoles are important as pharmaceuticals and agrochemicals. Generally, electrophilic aromatic substitution or generation of carbanions/electrophilic trapping approach is used to introduce functional groups into unsubstituted heteroaromatics. However, these approaches have not been simple to apply to unsubstituted isoxazoles due to their poor nucleophilicity and instability under basic conditions. Recently several approaches have been reported to overcome these problems. This review summarizes the functionalization of isoxazoles, including SEAr reactions and C–H direct arylations, towards the step-by-step multifunctionalization of isoxazoles.1 Introduction2 SEAr Reaction of Isoxazoles3 Preparation of Isoxazolyl Anions and Their Use for the Synthesis of Functionalized Isoxazoles4 Other C–C and C–N Bond Formations of Isoxazoles5 Transition-Metal-Catalyzed C–H Direct Functionalization of Isoxazoles6 Step-by-Step Multifunctionalization of Isoxazoles7 Summary and Outlook

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2

Yoshimura, Akira, Akio Saito, Viktor V. Zhdankin, and Mekhman S. Yusubov. "Synthesis of Oxazoline and Oxazole Derivatives by Hypervalent-Iodine-Mediated Oxidative Cycloaddition Reactions." Synthesis 52, no. 16 (May 18, 2020): 2299–310. http://dx.doi.org/10.1055/s-0040-1707122.

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Organohypervalent iodine reagents are widely used for the preparation of various oxazolines, oxazoles, isoxazolines, and isoxazoles. In the formation of these heterocyclic compounds, hypervalent iodine species can serve as the activating reagents for various substrates, as well as the heteroatom donor reagents. In recent research, both chemical and electrochemical approaches toward generation of hypervalent iodine species have been utilized. The in situ generated active species can react with appropriate substrates to give the corresponding heterocyclic products. In this short review, we summarize the hypervalent-iodine-mediated preparation of oxazolines, oxazoles, isoxazolines, and isoxazoles starting from various substrates.1 Introduction2 Synthesis of Oxazolines3 Synthesis of Oxazoles4 Synthesis of Isoxazolines5 Synthesis of Isoxazoles6 Conclusion

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3

Fershtat, Leonid L., Daniil A. Chaplygin, Ivan V. Ananyev, and Nina N. Makhova. "Divergent Synthesis of Five-Membered Nitrogen Heterocycles via Cascade Reactions of 4-Arylfuroxans." Synthesis 52, no. 18 (May 5, 2020): 2667–78. http://dx.doi.org/10.1055/s-0040-1707393.

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A novel method for the synthesis of a diverse series of functionally substituted five-membered heterocyclic compounds via atom-economic, regio-, and diastereoselective one-pot reaction cascade was developed. This approach involves a ring opening in 4-arylfuroxans to α-oximinoarylacetonitrile oxides followed by [3+2] cycloaddition to various dipolarophiles to afford multisubstituted isoxazoles and isoxazolines. Subsequent azole–azole rearrangement of (oximino)isoxazolines/-isoxazoles, which can be conducted in a one-pot manner, results into functionally substituted furazans formation. The developed protocol is operationally simple, proceeds in mild conditions and with high yields of target heterocyclic systems. Overall, this study represents a new mode of isoxazole and 1,2,5-oxadiazole functionalization strategy, which is useful in medicinal and materials chemistry.

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4

Chikkula, Krishna Veni, and Raja S. "ISOXAZOLE – A POTENT PHARMACOPHORE." International Journal of Pharmacy and Pharmaceutical Sciences 9, no. 7 (July 1, 2017): 13. http://dx.doi.org/10.22159/ijpps.2017.v9i7.19097.

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Isoxazole is an azole with an oxygen atom next to the nitrogen. Isoxazole rings are found in some natural products, such as ibotenic acid and also found in a number of drugs, including COX-2 inhibitor valdecoxib. Furoxan, a nitric oxide donor is containing isoxazolyl group & found in many β-lactamase resistant antibiotics, such as cloxacillin, dicloxacillin and flucloxacillin. The synthetic androgenic steroid danazol also has an isoxazole ring. The substituted isoxazoles are well developed in literature to posses significant biological activities. The disubstituted and trisubstituted isoxazoles have been reported to exhibit broad range of biological activities such as antimicrobial activity, analgesic activity, antiinflammatory activity, antioxidant activity, anticancer activity, CNS activity, antitubercular activity and miscellaneous activities like GABA agonistic activity, inhibitory activity, antihypertensive activity, and glutamate transporter activity. The present review summarizes up to date information of various biological activities of isoxazole analogs.

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5

Griesbeck, Axel G., Marco Franke, Jörg Neudörfl, and Hidehiro Kotaka. "Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies." Beilstein Journal of Organic Chemistry 7 (January 26, 2011): 127–34. http://dx.doi.org/10.3762/bjoc.7.18.

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The first photocycloadditions of aromatic and aliphatic aldehydes to methylated isoxazoles are reported. The reactions lead solely to the exo-adducts with high regio- and diastereoselectivities. Ring methylation of the isoxazole substrates is crucial for high conversions and product stability. The 6-arylated bicyclic oxetanes 9a–9c were characterized by X-ray structure analyses and showed the highest thermal stabilities. All oxetanes formed from isoxazoles were highly acid-sensitive and also thermally unstable. Cleavage to the original substrates is dominant and the isoxazole derived oxetanes show type T photochromism.

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6

Thirunarayanan, G., and V. Sathiyendiran. "Synthesis, Pharmacological and Insect Antifeedant Activities of some 3-(2-Naphthyl)-5-(Substituted Phenyl)-4,5-Dihydroisoxazoles." International Letters of Chemistry, Physics and Astronomy 49 (April 2015): 1–14. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.49.1.

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Totally thirty one 3,5-substituted aryl 4,5-dihydro isoxazole derivatives including 3-(2-naphthyl)-5-(substituted phenyl)-4,5-dihydroisoxazole have been synthesized by fly-ash:H2SO4 catalyzed cyclization of hydroxylamine hydrochloride and aryl chalcones under solvent-free conditions. The yields of the isoxazoles are more than 94%. The synthesized isoxazole were characterized by their physical constants and spectral data. The antimicrobial, antioxidant and insect antifeedant activities of the synthesized isoxazoles have been evaluated using a variety of bacterial and fungal species, DPPH radical scavenging and castor-leaf disc bioassay of 4th instar larvae Achoea Janata L methods.

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7

Camoutsis, Ch, and S. Nikolaropoulos. "Steroidal isoxazoles, isoxazolines and isoxazolidines." Journal of Heterocyclic Chemistry 35, no. 4 (July 1998): 731–59. http://dx.doi.org/10.1002/jhet.5570350401.

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8

Cherton, Jean-Claude, Marc Lanson, Daïf Ladjama, Yvette Guichon, and Jean-Jacques Basselier. "Synthèse d'isoxazoles substitués en α de l'azote par une chaine alkyle ou alcényle." Canadian Journal of Chemistry 68, no. 8 (August 1, 1990): 1271–76. http://dx.doi.org/10.1139/v90-196.

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Several syntheses of special isoxazoles bearing a long alkyl or alkenyl side chain in the α position of the nitrogen are presented. A very convenient route in the case of an alkyl side chain is the classical 1,3-dipolar cycloaddition of a nitrile-oxide to a vinyl acetate. Although it is a rather long approach, the reaction of hydroxylamine with enone-epoxides represents a new and unequivocal method compatible with alkenyl side chains. The isomerisation of the easily synthesized isoxazoles bearing such substitutents α to the oxygen, by the reaction of their isoxazolium salts with hydroxylamine, is a fast and general method. Another very convenient access to "α-N substituted" isoxazoles is the coupling of magnesium compounds with 3-bromomethyl 5-methyl isoxazole. Keywords: isoxazoles, substitution in the α position of nitrogen.

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9

Svejstrup, Thomas D., Wojciech Zawodny, James J. Douglas, Damon Bidgeli, Nadeem S. Sheikh, and Daniele Leonori. "Visible-light-mediated generation of nitrile oxides for the photoredox synthesis of isoxazolines and isoxazoles." Chemical Communications 52, no. 83 (2016): 12302–5. http://dx.doi.org/10.1039/c6cc06029c.

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10

Rey, Marine, and Stéphane Beaumont. "Molybdenum-Mediated One-Pot Synthesis of Pyrazoles from Isoxazoles." Synthesis 51, no. 20 (August 26, 2019): 3796–804. http://dx.doi.org/10.1055/s-0039-1690615.

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A one-pot approach for the direct synthesis of substituted pyrazoles from isoxazoles is reported. The process involves isoxazole N–O bond cleavage mediated by a molybdenum complex, in situ hydrolysis of the resulting β-amino enone to the corresponding 1,3-diketone, followed by pyrazole formation in the presence of hydrazine or substituted hydrazine. Good to excellent yields and regioselectivities are obtained with nonsymmetric isoxazoles. By using readily available starting materials, a wide range of substituted pyrazoles may be synthesized by this method.

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11

Pajkert, Romana, Henryk Koroniak, Paweł Kafarski, and Gerd-Volker Röschenthaler. "Hypervalent-iodine mediated one-pot synthesis of isoxazolines and isoxazoles bearing a difluoromethyl phosphonate moiety." Organic & Biomolecular Chemistry 19, no. 22 (2021): 4871–76. http://dx.doi.org/10.1039/d1ob00685a.

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12

Lin, Yifan, Ke Zhang, Mingchun Gao, Zheyi Jiang, Jiajie Liu, Yurui Ma, Haoyu Wang, Qitao Tan, Junjie Xiao, and Bin Xu. "Copper nitrate-mediated synthesis of 3-aryl isoxazolines and isoxazoles from olefinic azlactones." Organic & Biomolecular Chemistry 17, no. 22 (2019): 5509–13. http://dx.doi.org/10.1039/c9ob00857h.

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13

Liu, Hui, Yingkun Yan, Jiayan Zhang, Min Liu, Shaobing Cheng, Zhouyu Wang, and Xiaomei Zhang. "Enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines." Chemical Communications 56, no. 88 (2020): 13591–94. http://dx.doi.org/10.1039/d0cc05807f.

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Enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines provided various (bridged) isoxazolines fused dihydrobenzofurans with moderate to good yields in moderate to good enantioselectivities.

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14

Mohammed, Shabber, Ram A. Vishwakarma, and Sandip B. Bharate. "Metal-free DBU promoted regioselective synthesis of isoxazoles and isoxazolines." RSC Advances 5, no. 5 (2015): 3470–73. http://dx.doi.org/10.1039/c4ra14694h.

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15

Pramanik, Nabyendu, Satinath Sarkar, Dipanwita Roy, Sudipto Debnath, Sukla Ghosh, Saikat Khamarui, and Dilip K. Maiti. "Synthesis and diverse general oxidative cyclization catalysis of high-valent MoVIO2(HL) to ubiquitous heterocycles and their chiral analogues with high selectivity." RSC Advances 5, no. 123 (2015): 101959–64. http://dx.doi.org/10.1039/c5ra21825j.

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The first synthesis and diverse oxidative cyclization catalysis properties of high-valent Mo^VI–triazole are demonstrated towards highly selective construction of benzimidazoles, benzothiazoles, isoxazolines, isoxazoles and their chiral analogues.

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16

Obydennov, Dmitrii L., Asmaa I. El-Tantawy, and Vyacheslav Ya Sosnovskikh. "Bio-based triacetic acid lactone in the synthesis of azaheterocyclesviaa ring-opening transformation." New Journal of Chemistry 42, no. 11 (2018): 8943–52. http://dx.doi.org/10.1039/c8nj01044g.

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In the present article a new way of converting biobased triacetic acid lactone (TAL) into azaheterocyclic compounds, such as 4-pyridones, pyrazoles, isoxazolines and isoxazoles, has been found through reactive and multifunctional polycarbonyl intermediates.

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17

Beccalli, E. M., A. Marchesini, and T. Pilati. "Oxazolo[4,5-d]isoxazole Derivatives and 3,4-Disubstituted Isoxazoles from Isoxazol-5(4H)-ones." Synthetic Communications 23, no. 5 (March 1, 1993): 685–702. http://dx.doi.org/10.1080/00397919308009828.

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18

De Micheli, Carlo, Patrizia Caldirola, Marco De Amichi, and Paolo Pevarello. "An Efficient Synthesis of Isoxazoles and Isoxazolines." HETEROCYCLES 23, no. 10 (1985): 2479. http://dx.doi.org/10.3987/r-1985-10-2479.

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19

Pruitt, James R., Donald J. Pinto, Melissa J. Estrella, Lori L. Bostrom, Robert M. Knabb, Pancras C. Wong, Matthew R. Wright, and Ruth R. Wexler. "Isoxazolines and isoxazoles as factor Xa inhibitors." Bioorganic & Medicinal Chemistry Letters 10, no. 8 (April 2000): 685–89. http://dx.doi.org/10.1016/s0960-894x(00)00097-4.

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20

CAMOUTSIS, CH, and S. NIKOLAROPOULOS. "ChemInform Abstract: Steroidal Isoxazoles, Isoxazolines and Isoxazolidines." ChemInform 29, no. 52 (June 18, 2010): no. http://dx.doi.org/10.1002/chin.199852329.

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21

Kumar, Vinod, and Kamalneet Kaur. "Fluorinated isoxazolines and isoxazoles: A synthetic perspective." Journal of Fluorine Chemistry 180 (December 2015): 55–97. http://dx.doi.org/10.1016/j.jfluchem.2015.09.004.

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22

Karthikeyan, K., R. Senthil Kumar, P. Dheenkumar, and Paramasivan T. Perumal. "Solvent and catalyst free route to 3-indolyl glycoconjugates: synthesis of sugar tethered isoxazolines and isoxazoles from 3-indolyl nitroalkanes." RSC Adv. 4, no. 53 (2014): 27988–97. http://dx.doi.org/10.1039/c4ra02825b.

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An expedient, solvent and catalyst free strategy for the synthesis of sugar based bis(indolyl)methanes and indolyl nitroalkanes has been developed. Further, the nitroalkanes were converted to novel isoxazolines and isoxazoles by nitrile oxides cycloaddition.

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23

Al-Zaydi, Khadijah Mohamed, and Ebtisam Abdel Aziz Hafez. "1,3-Dipolar Cycloadditions of Some Nitrilimines and Nitrile Oxides to 3-N,N-Dimethylamino-1 -oxopropene Derivatives." Journal of Chemical Research 23, no. 6 (June 1999): 360–61. http://dx.doi.org/10.1177/174751989902300608.

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An efficient synthesis of some novel pyrazoles 8a-j, 13a-e, 18a,b, isoxazoles 26a-g, pyrazolo[3,4- d]pyridazines 9a-d and isoxazolo[3,4- d]pyridazines 27a-d via 1,3-dipolar cycloaddition reactions is reported.

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24

Mahalanabis, Kumar K., S. K. Dutta Chowdhury, Mili Sarkar, and Manisha Misra. "Synthesis of substituted isoxazolones and isoxazoles from cyanoenaminones." Journal of Chemical Research 2006, no. 2 (February 1, 2006): 78–80. http://dx.doi.org/10.3184/030823406776330864.

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25

Sammelson, Robert, Daniel Miller, and Christopher Bailey. "Synthesis of Isoxazolines and Isoxazoles Inspired by Fipronil." Synthesis 47, no. 18 (July 29, 2015): 2791–98. http://dx.doi.org/10.1055/s-0034-1378737.

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26

Jedlovská, Eva, Lubor Fišera, Anna Balková, Jaroslav Kováč, and Ladislav Štibrányi. "Cycloadditions of 2,5-dimethyl-3-furannitrile oxide to alkenes and alkynes." Collection of Czechoslovak Chemical Communications 55, no. 10 (1990): 2481–92. http://dx.doi.org/10.1135/cccc19902481.

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Regioselectivity of 1,3-dipolar cycloadditions of 2,5-dimethyl-3-furannitrile oxide (IIa) to alkenes or alkynes is described. Nitrile oxide IIa generated in situ reacts with monosubstituted alkenes or alkynes to give exclusively 5-substituted 3-(5-dimethyl-3 -furyl)-2-isoxazolines IV and isoxazoles V, 2,5-disubstituted alkenes sometimes afforded a mixture of regioisomeric isoxazolines. Reactivity of furannitrile oxides II and III in cycloadditions to ethene was studied by the MNDO method.

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27

BECCALLI, E. M., A. MARCHESINI, and T. PILATI. "ChemInform Abstract: Oxazolo(4,5-d)isoxazole Derivatives and 3,4-Disubstituted Isoxazoles from Isoxazol-5(4H)-ones." ChemInform 24, no. 26 (August 20, 2010): no. http://dx.doi.org/10.1002/chin.199326129.

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28

Pan, Xinhui, Xiaobing Xin, Ying Mao, Xin Li, Yanan Zhao, Yidi Liu, Ke Zhang, Xiaoda Yang, and Jinhui Wang. "3-Benzoylisoxazolines by 1,3-Dipolar Cycloaddition: Chloramine-T-Catalyzed Condensation of α-Nitroketones with Dipolarophiles." Molecules 26, no. 12 (June 8, 2021): 3491. http://dx.doi.org/10.3390/molecules26123491.

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In this study, 3-benzoylisoxazolines were synthesized by reacting alkenes with various α-nitroketones using chloramine-T as the base. The scope of α-nitroketones and alkenes is extensive, including different alkenes and alkynes to form various isoxazolines and isoxazoles. The use of chloramine-T, as the low-cost, easily handled, moderate base for 1,3-dipolar cycloaddition is attractive.

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29

Saleem, Tahira, Muhammad Humble Khalid Tareen, Muhammad Rashid, Mehwish Nawaz, Hina Aftab, Rabia Batool, Ammara Chand, and Ayesha Ahmed Sumra. "REVIEW ON THE SYNTHESIS AND POTENTIAL THERAPEUTIC APPLICATIONS OF HETEROCYCLIC PRODUCTS OF 5-AMINO-3-METHYLISOXAZOLE." International Journal of Scientific & Engineering Research 12, no. 08 (August 25, 2021): 154–72. http://dx.doi.org/10.14299/ijser.2021.08.01.

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In general, heterocyclic compounds have evoked interest and concern because of their fundamental role in biological profiles and biological actions in nature. Now, most of the lead molecules in medicinal chemistry are based on hetero-atoms. In medicinal chemistry- to bring two hetero-atoms to the drug molecule, isoxazoles are interesting functional groups. Isoxazole as a key building block has been widely used and is an important heterocyclic unit.

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30

Pruitt, James R., Donald J. Pinto, Melissa J. Estrella, Lori L. Bostrom, Robert M. Knabb, Pancras C. Wong, Matthew R. Wright, and Ruth R. Wexler. "ChemInform Abstract: Isoxazolines and Isoxazoles as Factor Xa Inhibitors." ChemInform 31, no. 30 (June 7, 2010): no. http://dx.doi.org/10.1002/chin.200030111.

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31

Chukanov, N. V., S. A. Popov, G. V. Romanenko, and V. A. Reznikova. "Transformation of 1,2,3,7a-tetrahydroimidazo[1,2-b]isoxazole derivatives into isoxazoles." Russian Chemical Bulletin 56, no. 6 (June 2007): 1227–33. http://dx.doi.org/10.1007/s11172-007-0185-y.

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32

Aristova, N. V., B. I. Gorin, S. V. Kovalenko, V. A. Pavlov, and V. V. Moskva. "Phosphorylated isoxazoles." Chemistry of Heterocyclic Compounds 26, no. 9 (September 1990): 1076. http://dx.doi.org/10.1007/bf00472499.

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33

Beccalli, Egle M., Maria Luisa Gelmi, and Alessandro Marchesini. "Trisubstituted isoxazoles from 3,4-disubstituted-(2H)-isoxazol-5-ones." Tetrahedron 54, no. 47 (November 1998): 14401–6. http://dx.doi.org/10.1016/s0040-4020(98)00891-6.

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34

Sun, Qiu, Ling He, Jiaxin Cheng, Ze Yang, Yuansheng Li, and Yulan Xi. "Synthesis of Isoxazolines and Isoxazoles via Metal-Free Desulfitative Cyclization." Synthesis 50, no. 12 (May 14, 2018): 2385–93. http://dx.doi.org/10.1055/s-0037-1609480.

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A novel, one-pot reaction for the synthesis of isoxazolines and isoxazoles is developed via a cascade process under metal-free conditions. The approach involves the formation of intramolecular C–N and C–O bonds and intermolecular C–C bonds from aromatic alkenes or alkynes and N-hydroxysulfonamides using hypervalent iodine(VII) and iodine as the oxidant. Activation of C–H and C–C bonds/construction of C–O bonds/elimination of SO2/C–N bond formation is achieved in sequence in the reaction system.

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35

Khlebnikov, Alexander F., Mikhail S. Novikov, Yelizaveta G. Gorbunova, Ekaterina E. Galenko, Kirill I. Mikhailov, Viktoriia V. Pakalnis, and Margarita S. Avdontceva. "Isoxazolium N-ylides and 1-oxa-5-azahexa-1,3,5-trienes on the way from isoxazoles to 2H-1,3-oxazines." Beilstein Journal of Organic Chemistry 10 (August 14, 2014): 1896–905. http://dx.doi.org/10.3762/bjoc.10.197.

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Theoretical and experimental studies of the reaction of isoxazoles with diazo compounds show that the formation of 2H-1,3-oxazines proceeds via the formation of (3Z)-1-oxa-5-azahexa-1,3,5-trienes which undergo a 6π-cyclization. The stationary points corresponding to the probable reaction intermediates, isoxazolium N-ylides, were located by DFT calculations at the B3LYP/6-31G(d) level only for derivatives without a substituent in position 3 of the isoxazole ring. These isoxazolium N-ylides are thermodynamically and kinetically very unstable. According to the calculations and experimental results 2H-1,3-oxazines are usually more thermodynamically stable than the corresponding open-chain isomers, (3Z)-1-oxa-5-azahexa-1,3,5-trienes. The exception are oxaazahexatrienes derived from 5-alkoxyisoxazoles, which are thermodynamically more stable than the corresponding 2H-1,3-oxazines. Therefore, the reaction of diazo esters with 5-alkoxyisoxazoles is a good approach to 1,4-di(alkoxycarbonyl)-2-azabuta-1,3-dienes. The reaction conditions for the preparation of aryl- and halogen-substituted 2H-1,3-oxazines and 1,4-di(alkoxycarbonyl)-2-azabuta-1,3-dienes from isoxazoles were investigated.

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36

JAROSKOVA, L., and L. FISERA. "ChemInform Abstract: Preparation of 2,4-Dichlorobenzoyl-Substituted Isoxazolines and Isoxazoles." ChemInform 25, no. 34 (August 19, 2010): no. http://dx.doi.org/10.1002/chin.199434154.

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37

Karthikeyan, K., T. Veenus Seelan, K. G. Lalitha, and P. T. Perumal. "Synthesis and antinociceptive activity of pyrazolyl isoxazolines and pyrazolyl isoxazoles." Bioorganic & Medicinal Chemistry Letters 19, no. 13 (July 2009): 3370–73. http://dx.doi.org/10.1016/j.bmcl.2009.05.055.

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38

Escudero, Julien, Veronique Bellosta, and Janine Cossy. "Synthesis of Isoxazolidines, Isoxazolines and Isoxazoles from O-Unsaturated Alkoxyamines." Letters in Organic Chemistry 15, no. 5 (April 12, 2018): 365–74. http://dx.doi.org/10.2174/1570178614666171023161721.

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39

Fišera, Lubor, and Peter Oravec. "Stereoselectivity of cycloadditions of arylnitrile oxides to 5-alkoxy-2(5H)-furanone." Collection of Czechoslovak Chemical Communications 52, no. 5 (1987): 1315–24. http://dx.doi.org/10.1135/cccc19871315.

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1,3-Dipolar cycloaddition of arylnitrile oxides to 5-alkoxy-2(5H)-furanones (II) and 5-hydroxy-2(5H)-furanone leads regiospecifically to 4-oxo-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazole derivatives IIIa-IIIj. The alkoxy derivatives give exclusively products of exo-configuration (III), whereas the hydroxy compound affords a 52 : 48 mixture of both diastereoisomers IIIj and IVj. Reaction of III with ammonia furnished diastereoisomeric tetrahydropyrrolo[3,4-d]isoxazoles V and VI, reaction with hydrazines led to hexahydroisoxazolo[4,5-d]pyridazin-7-one derivatives VII.

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40

Kiyani, Hamzeh, and Asiyeh Mosallanezhad. "Sulfanilic Acid-catalyzed Synthesis of 4-arylidene-3-substituted isoxazole-5(4H)-ones." Current Organic Synthesis 15, no. 5 (July 5, 2018): 715–22. http://dx.doi.org/10.2174/1570179415666180423150259.

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Aim and Objective: In recent studies, chemistry of heterocyclic compounds, especially isoxazoles, has been widely considered by organic chemistry researchers because they have been found in many molecules, including naturally occurring bioactive compounds, pharmaceuticals, and agrichemicals. Isoxazol- 5(4H)-ones and their derivatives, on the other hand, have significant biological properties can be mentioned as examples of antibacterial, anti-inflammatory, antifungal, anticancer, analgesic, fungicidal, and insecticidal activities. Therefore, the development of ecofriendly methods, such as three-component processes, for the synthesis of isoxazol-5(4H)-ones is highly desirable. This work focus on the one-pot, three-component reaction (3-CR) of aldehydes, hydroxylamine hydrochloride, and three β-ketoester using catalytic amounts of sulfanilic acid (SA) aimed at the synthesis of isoxazol-5(4H)-ones. Another aim of this study is to use water as a green solvent for the above-mentioned 3-CR. <p> Materials and Methods: Using SA as an efficient organocatalyst, the multicomponent cyclocondensation of aromatic/hetero-aromatic aldehydes, hydroxylamine hydrochloride, and ethyl acetoacetate/ethyl 4- chloroacetoacetate/ethyl benzoylacetate has been implemented. The reactions were carried out in water as a green solvent at room temperature. The corresponding heterocyclic products were separated by simple filtration and washing with water. Also, the solvent was removed from the filtrate by evaporation to recycle the catalyst. Results: It was found that SA act as the catalyst for the synthesis of 4-arylidene-3-substituted isoxazole-5(4H)- ones via three-component reaction of aromatic/hetero-aromatic aldehydes, hydroxylamine hydrochloride, and three β-dicarbonyl compounds (ethyl acetoacetate, ethyl 4-chloroacetoacetate, and ethyl benzoylacetate). Optimization of the catalyst quantity and solvent showed that the highest yield was achieved with 20 mol% of SA in aqueous media. 4-Arylidene-3-substituted isoxazole-5(4H)-ones have been successfully synthesized in the presence of SA catalyst. Conclusion: The SA catalyst could be recovered easily from the filtrate via evaporation of solvent and reused many times. The present synthetic method is a simple, green, clean, and environmentally friendliness alternative for synthesizing 4-arylidene-3-substituted isoxazole-5(4H)-ones. Reactions were performed without the use of heating, microwave and ultrasound irradiations.

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Averina, Elena, Dmitry Vasilenko, Kseniya Sedenkova, and Tamara Kuznetsova. "Synthetic Approaches to Nitro-Substituted Isoxazoles." Synthesis 51, no. 07 (February 27, 2019): 1516–28. http://dx.doi.org/10.1055/s-0037-1611714.

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Nitro-substituted isoxazoles are of utmost interest both as versatile intermediates for targeted organic synthesis and as perspective bioactive compounds for drug development. Nevertheless, the existing approaches to them usually lack generality and strongly depend on the position of the nitro group and on the presence of other substituents in the isoxazole ring. This review provides the first systematization of all available data concerning synthetic approaches to 3-, 4-, and 5-nitroisoxazoles. There are a number of preparative approaches to 4-nitroisoxazoles based on classical heterocyclization reactions of nitro-substituted compounds and the nitration of isoxazoles. 3-Nitro- and, especially, 5-nitroisoxazoles are much less readily available. A few methods affording 3-nitroisoxazoles have been reported, often employing the heterocyclization of unsaturated compounds by treatment with sodium nitrite. The sole general preparative method for 5-nitroisoxazoles, containing a variety of functional groups, employs the heterocyclization of electrophilic alkenes by treatment with tetranitromethane activated with triethylamine.1 Introduction2 Synthesis of 4-Nitroisoxazoles2.1 Nitration of Isoxazoles2.2 Condensations of α-Nitro Ketones or Their Oximes2.3 1,3-Dipolar Cycloaddition of Nitrile Oxides to Acetylenes and Their Synthetic Equivalents2.4 Heterocyclization of Acetylene Derivatives by Treatment with Sodium Nitrite2.5 Heterocyclization of Nitro Derivatives of 1,3-Diketones and Their Synthetic Equivalents2.6 Miscellaneous Methods3 Synthesis of 3-Nitroisoxazoles3.1 Heterocyclization of Acetylene Derivatives or 1,3-Dihalogenoalkenes by Treatment with Sodium Nitrite3.2 Heterocyclization of Morita–Baylis–Hillman Acetates by Treatment with Sodium Nitrite3.3 1,3-Dipolar Cycloadditions4 Synthesis of 5-Nitroisoxazoles4.1 1,3-Dipolar Cycloadditions4.2 Synthesis Using Polynitro Compounds5 Conclusion

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Cherton, Jean-Claude, M. Lanson, D. Ladjama, N. Lefebvre, Z. Vossough, and J.-J. Basselier. "Synthèse d'isoxazoles substitués en α de l'oxygène et d'isoxazoles substitués en α de l'azote et de l'oxygène par des chaînes alkyle ou alcényle." Canadian Journal of Chemistry 69, no. 4 (April 1, 1991): 625–31. http://dx.doi.org/10.1139/v91-095.

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Two series of isoxazoles substituted by long alkyl or alkenyl chains in the α position with respect to the oxygen atom or in the α position with respect to the two heteroatoms have been synthesized. Starting from 3,5-dimethylisoxazole, the regioselective metalation/alkylation on the α-O methyl group was a very convenient route to a large variety of "α-O substituted isoxazoles". When applied to α-O methylated isoxazoles bearing an α-N alkenyl chain the same method provides an original unequivocal approach to 3,5-dialkenyl isoxazoles. An alternative route to these compounds, despite the formation of di-isoxazoline as by-product and an additional step corresponding to the oxidation of the intermediate isoxazoline, is the 1,3-dipolar cycloaddition, by using terminal dienes as dipolarophiles with alkenyl dipoles. Nevertheless, the cycloaddition between monoalkylated alcynes and alkylated dipoles remains the most straightforward synthesis of 3,5-dialkyl isoxazoles. Key words: isoxazoles, alkenyl side chains, metalation–alkylation, regioselectivity.

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ZOHDI, H. F., F. A. KHALIFA, A. O. ABDELHAMID, and A. A. EL-TOURGMAN. "ChemInform Abstract: Heterocycles from Nitrile Oxides: Synthesis of Some New Isoxazoles, Pyrrolo(3,4-d)isoxazoles and Isoxazolo(3,4-d)pyridazines." ChemInform 23, no. 9 (August 22, 2010): no. http://dx.doi.org/10.1002/chin.199209186.

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Margaretha, P. "ChemInform Abstract: Isoxazoles." ChemInform 42, no. 33 (July 22, 2011): no. http://dx.doi.org/10.1002/chin.201133239.

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Singh, Okram Mukherjee, H. Junjappa, and H. Ila. "A Facile Synthesis of 3-Cyclopropyl- and 5-Cyclopropyl-isoxazoles." Journal of Chemical Research 23, no. 6 (June 1999): 398–99. http://dx.doi.org/10.1177/174751989902300627.

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Chen, Wen-Chang, Veerababurao Kavala, Yu-Hsuan Shih, Yu-Hsuan Wang, Chun-Wei Kuo, Tang-Hao Yang, Chia-Yu Huang, Hao-Hsiang Chiu, and Ching-Fa Yao. "Synthesis of Bicyclic Isoxazoles and Isoxazolines via Intramolecular Nitrile Oxide Cycloaddition." Molecules 20, no. 6 (June 12, 2015): 10910–27. http://dx.doi.org/10.3390/molecules200610910.

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Pérez, Juana M., and Diego J. Ramón. "Synthesis of 3,5-Disubstituted Isoxazoles and Isoxazolines in Deep Eutectic Solvents." ACS Sustainable Chemistry & Engineering 3, no. 9 (August 18, 2015): 2343–49. http://dx.doi.org/10.1021/acssuschemeng.5b00689.

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48

JEDLOVSKA, E., and L. FISERA. "ChemInform Abstract: Synthesis of Furyl-Substituted Isoxazoles, Isoxazolines, and 1,2,4- Oxadiazoles." ChemInform 24, no. 4 (August 21, 2010): no. http://dx.doi.org/10.1002/chin.199304171.

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Wang, Yan-Guang, and Yong-Jia Shang. "Synthesis of Isoxazolines and Isoxazoles Using Poly(ethylene glycol) as Support." Synthesis 2002, no. 12 (2002): 1663–68. http://dx.doi.org/10.1055/s-2002-33655.

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Beccalli, Egle M., Alessandro Marchesini, and Tullio Pilati. "Imidazoles and Pyrrolo[2,3-d]isoxazoles from Isoxazol-5(4H)-ones." Synthesis 1991, no. 02 (1991): 127–31. http://dx.doi.org/10.1055/s-1991-26396.

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