Journal ArticleDOI
Rearrangements of N-alkyl-/aryl-nitrones derived from 4-oxo-4H-1-benzopyran-3-carboxaldehyde––a solvent-dependent process
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In this paper, the synthesis of 1-benzopyrano[3,4d]isoxazole-4-one has been studied using 3-(alkyl-/aryl-aminomethylene)chroman-2,4-dione depending upon the reaction medium.About:
This article is published in Tetrahedron Letters.The article was published on 2004-08-02. It has received 27 citations till now. The article focuses on the topics: Solvent effects & Benzopyran.read more
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Direct synthesis of trisubstituted isoxazoles through gold-catalyzed domino reaction of alkynyl oxime ethers.
TL;DR: Alkynyl oxime ether underwent a gold-catalyzed domino reaction involving cyclization and subsequent Claisen-type rearrangement to afford trisubstituted isoxazoles in a direct, efficient, and regioselective manner.
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Efficient and regioselective one-pot synthesis of 3-substituted and 3,5-disubstituted isoxazoles.
TL;DR: A series of 3-substituted and 3,5-disubstituting isoxazoles have been efficiently synthesized in moderate to excellent yields by the reaction of N-hydroxyl-4-toluenesulfonamide with alpha,beta-unsaturated aldehydes/ketones.
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New developments of ketonitrones in organic synthesis
TL;DR: In this article, a review describes some recent breakthroughs in the development of new transformation of N-substituents α,β-unsaturated ketonitrones or N-vinyl nitrones, and reaction of nitrones with dipolarophiles such as alkynes, allenes and isocyanates.
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Reactions of 3-(polyfluoroacyl)chromones with hydroxylamine: synthesis of novel RF-containing isoxazole and chromone derivatives
TL;DR: In this article, the pyrone ring of 3-polyfluoroacyl-4 H -chromeno[3,4- d ]isoxazol-4-ols was opened by nucleophilic 1, 4-addition and subsequent cyclization to 4 polyfluoroalkyl)-4 H-chromeno, which was then converted to 3-R F -4-salicyloylisoxazoles by simple heating.
Journal ArticleDOI
Silver-catalyzed synthesis of disubstituted isoxazoles by cyclization of alkynyl oxime ethers
Masafumi Ueda,Yuki Ikeda,Aoi Sato,Yuta Ito,Maiko Kakiuchi,Hiroko Shono,Tetsuya Miyoshi,Takeaki Naito,Okiko Miyata +8 more
TL;DR: In this paper, a facile and practical synthesis of 3,5-disubstituted isoxazoles via a silver-catalyzed cyclization and subsequent protonation of alkynyl oxime ethers has been developed.
References
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Regel zur Abschätzung der chemischen Verschiebung von Protonen an einer Doppelbindung
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Synthesis of Coumarins with 3:4-Fused Ring Systems and their Physiological Activity
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A versatile route to 2-alkyl-/aryl-amino-3-formyl- and hetero-annelated-chromones, through a facile nucleophilic substitution at C2 in 2-(N-methylanilino)-3-formylchromones
TL;DR: The N-methylanilino group in 2-(Nmethylonilino)-3-formylchromones, obtained in high yield by rearrangement of C(4-oxo-4H[1]-benzopyran-3-yl)-N-phenylnitrones to 2-anilino-3 -formyl-chromones followed by N-methylation, undergoes facile nucleophilic substitution by a variety of nitrogen nucleophiles, thereby paving the way for synthesis of novel 2-substituted
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Synthesis of Coumarin Derivatives from 4-Oxo-4H-1-benzopyran-3-carboxaldehyde via 3-(Arylaminomethylene)chroman-2,4-dione
TL;DR: K-10 Montmorillonite mediated condensation of aldehyde 1 with arylamine 2 affords chroman-2,4-dione 5 which gives tricoumarol 8 by acid hydrolysis, 4-arylamino-3-formylcoumarin 11 and 1-benzopyrano[4,3-b]quinoline 12 on heating with POCl3 as discussed by the authors.
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Synthesis of [1]benzopyrano[3,4-d]isoxazol-4-ones from 2-substituted chromone-3-carboxylic esters: a reinvestigation of the reaction of 3-acyl-4-hydroxycoumarins with hydroxylamine ― Synthesis of 4-(2-hydroxybenzoyl)isoxazol-5-ones
Related Papers (5)
2-(N-Methylanilino)-3-formylchromone—a versatile synthon for incorporation of chromone moiety in a variety of heterocyclic systems and macrocycles through reactions with bifunctional nucleophiles
A versatile route to 2-alkyl-/aryl-amino-3-formyl- and hetero-annelated-chromones, through a facile nucleophilic substitution at C2 in 2-(N-methylanilino)-3-formylchromones
The synthesis of highly substituted isoxazoles by electrophilic cyclization: an efficient synthesis of valdecoxib.
Jesse Waldo,Richard C. Larock +1 more