- REACTION OF CHROMONES WITH HYDROXYLAMINE IN ANHYDROUS METHANOL. A NOVEL ROUTE FOR THE PREPARATION OF CHROMONE OXIMES
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The reaction of 4H-1-benzopyran-4-one (chromone, 1) and its substituted derivatives with hydroxylamine in aqueous alcohols gives isoxazoles 5, and 10, as the major products, whereas 1a is transformed mainly into 8a with hydroxylamine hydrochloride in anhydrous methanol; compounds 5a, 9a and 10a can also be isolated, and the formation of 6a and 7a has been detected, as well.Depending on the character of the substituent, substituted chromones 1b-g afforded 7, 8 or 9 as the isolable major product.Based on the present experiments compound 6, produced in an acid-catalyzed methanol addition on 1, is regarded the key intermediate of the formation of chromone oxime
- Szabo, Vince,Borbely, Janos,Theisz, Edit,Nagy, Sandor
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p. 4215 - 4222
(2007/10/02)
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- THE REACTIONS OF CHROMONE AND 2-HYDROXYCHROMANONE WITH HYDROXYLAMINE
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Chromone and 2-hydroxychromanone react with hydroxylamine to give several products through attack at Ca2.The aldoxime 2 is transformed to dioxime 4 or to isoxazole 3.The dioxime exists as a tautomer mixture; it reacts in several ways, giving chromoneoxime
- Szabo, Vince,Borbely, Janos,Theisz, Edit,Borda, Jeno,Janzso, Geza
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p. 413 - 417
(2007/10/02)
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- A NEW PATHWAY IN THE REACTIONS OF CHROMONES AND HYDROXYLAMINE IN ANHYDROUS SOLUTIONS
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In the nucleophilic reaction of chromone (1) with NH2OH.HCl in anhydrous methanol a new compound 2-methoxychromanone (6) appeared as an intermediate in the formation of chromone oxime (8) and 2-methoxychromanone oxime (7).
- Szabo, Vince,Borbely, Janos,Theisz, Edit,Janzso, Geza
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p. 5347 - 5350
(2007/10/02)
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