Sodium salts of acylhydrazones of 1,3 - dioxocompounds and their acylation

Зеленин, K. Н.; Bezhan, I. P.; Ershov, B. A.; Zelenin, A. K.

doi:10.1016/s0040-4020(01)89284-x

Cited by 27 publications

(20 citation statements)

References 4 publications

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“…A bridged bicyclic compound obtained as a side product was assigned as a 4,5-dihydro-2,5-methano-1,4,3-dioxazepine. [3] We found, however, by subsequent studies, including X-ray analysis, that the above compounds were actually 5-isoxazolidinol (an unexpected isomer of the claimed 3-isoxazolidi-1,3-di-tert-butyl-5-methyl-2,7-dioxa-6-azabicyclo[3.2.1]oct-3-ene (6). The formation of these products involves the splitting of hydroxylamine in 2 and its re-addition as an O-nucleophile under acidic reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

et al. 2003

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We have studied the cyclization of (4Z)-2,2,5,8,8-pentamethyl-4-nonene-3,7-dione (3E)-oxime (2). We have previously claimed the formation of a stable 3,5,5-trisubstituted 3-isoxazolidinol and of a bridged bicycle 4,5-dihydro-2,5-methano-1,4,3-dioxazepine in the reaction of 2 with hydrochloric acid in anhydrous diethyl ether. We report in this article that the above compounds are actually 3,3-dimethyl-1-(5Ј-tert-butyl-5Ј-hydroxy-3Ј-methylisoxazolidin-3Ј-yl)butan-2-one (5) and

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Section: Introductionmentioning

confidence: 99%

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

et al. 2003

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confidence: 89%

“…Compounds Ia-c, which do not undergo ring opening in non-polar solvents [16] exhibit ring-chain equilibria A D B when dissolved in DMSO [17]. The same is true for the products obtained by substitution of their hemiacetal hydroxyl group with certain hydrazine derivatives [18]. On the other hand, the condensation between carbonyl compounds and either 2-aminomethylaniline or thioaroylhydrazines leads to cyclic structures 1,3,4-∆ 2 -thiadiazolines [19] or (1,2,3,4-tetrahydroquinazolines [20], respectively).…”

mentioning

confidence: 99%

Recyclizations of 2‐aminobenzylimines and thioaroylhydrazones of N‐substituted N‐hydroxy‐3‐oxobutanamides

Зеленин

Lagoda

Alekseyev

et al. 2002

Journal of Heterocyclic Chem

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A universal scheme is proposed for the molecular design of heterocyclic recyclizations by replacing the exocyclic hydroxyl groups in e x o -t r i g-ring-chain tautomeric molecules with substituted amines or hydrazines. The practical applicability of this approach is demonstrated by the condensations of 5-hydroxy-5-methyl-3-isoxazolidinones with thioaroyl-hydrazines and 2-aminomethylaniline. The condensation products were studied by modern 1 H, 1 3 C and 1 5 N NMR spectroscopic methods using three solvents: CDCl 3 , DMSO [D 6 ] and CD 3 CN. The solvent was found to have a strong effect to the relative amounts of the tautomers.

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“…[1][2][3] By conventional procedure, pyrazoles have been obtained by directly reacting β-diketones with hydrazine. 1 However, in most cases, 5-hydroxy-4,5-dihydro-1H-pyrazoles have been obtained when the N-1 atom is substituted with a strong electron-withdrawing group which stabilizes the -OH group and possibly hinders the elimination of the water molecule and the subsequent aromatization of the pyrazoline ring.…”

Section: Introductionmentioning

confidence: 99%

Regiospecific synthesis of new non-condensed heteropolycyclic systems from beta-heteroaryl-beta-methoxyvinyl trihalomethyl ketones

Bonacorso¹,

Oliveira²,

Costa³

et al. 2005

J. Braz. Chem. Soc.

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isonicotinoil-hidrazinas (heteroarilhidrazidas), realizadas sob condições brandas e em meio alcoólico, forneceram em passo reacional único e regioespecificamente, uma série inédita composta por doze heteroaroil-2-pirazolinas trialometil heteroaril substituídas em rendimentos de 50-78%; um novo sistema heteropolicíclico não condensado.A novel series of twelve heteroaroyl-2-pyrazolines trihalomethyl and substituted heteroaryl, as non-condensed heteropolycyclic systems, have been synthesized in one-step in 50-78% yield from the regiospecific cyclocondensation reaction of 1,1,1-trifluoro(chloro)-4-methoxy-4-(2-furyl)-and 4-(2-thienyl)-3-buten-2-ones (β-alkoxyvinyl trihalometil ketones) with furoic hydrazide, 2-thiophenecarboxylic hydrazide and isonicotinic acid hydrazide (heteroaroylhydrazines) under mild conditions in methanol as solvent.Keywords: 2-pyrazolines, pyrazoles, 4-alkoxy-1,1,1-trihalo-alk-3-en-2-ones, hydrazides, heteroaroylhydrazines, hydrazines IntroductionAlthough many methods have been published for the synthesis of 1H-pyrazoles and their derivatives, attempts to perform the synthesis of a simple 4,5-dihydro-1H-pyrazoles (2-pyrazolines), has not yet been sucessfully achieved.1-3 By conventional procedure, pyrazoles have been obtained by directly reacting β-diketones with hydrazine.1 However, in most cases, 5-hydroxy-4,5-dihydro-1H-pyrazoles have been obtained when the N-1 atom is substituted with a strong electron-withdrawing group which stabilizes the -OH group and possibly hinders the elimination of the water molecule and the subsequent aromatization of the pyrazoline ring. 1Regarding pharmacological applications, 2-pyrazolines (4,5-dihydro-1H-pyrazoles) have been found to possess antitumor, 4 antibacterial, antifungal, antiviral, antiparasitic, antitubercular and insecticidal and others properties. [5][6][7][8][9][10][11][12][13][14][15][16] Some of these compounds also presented anti-inflammatory, anti-diabetic, anesthetic and analgesic properties. [13][14][15] For example, in a recent work Mamolo et al. 16 have synthesized a series of 5-aryl-1-isonicotinoyl-3-(pyridin-2-yl)-4,5-dihydro-1H-pyrazoles in a three-step in low yields, which involved an aldol condensation, cyclocondensation with hydrazine and N-acylation with isonicotinoyl chloride. These 2-pyrazolines showed an interesting antimycobacterial activity in vitro.In 2002, our research group reported 17 a new approach for the synthesis of a series of four ketones as 1,1,1-trifluoro(chloro)-4-methoxy-4-(2-furyl)-and 4-(2-thienyl)-3-buten-2-ones and their 4,4,4-trihalo-1-(2-heteroaryl)-1,3-butanediones derivatives. The autors also showed that mixtures of β-alkoxyvinyl trifluoromethyl ketones and the respective 1,3-butanediones derived from 2-acetylthiophene and 2-acetylfuran react with hydroxylamine hydrochloride, dry hydrazine and thiosemicarbazide hydrochloride leading to 3-(2-thienyl)-and 3-(2-furyl)azoles 869 Regiospecific Synthesis of New Non-Condensed Heteropolycyclic Systems Vol. 16, No. 4, 2005 derivatives. In this case, only one ...

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Sodium salts of acylhydrazones of 1,3 - dioxocompounds and their acylation

Cited by 27 publications

References 4 publications

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Recyclizations of 2‐aminobenzylimines and thioaroylhydrazones of N‐substituted N‐hydroxy‐3‐oxobutanamides

Regiospecific synthesis of new non-condensed heteropolycyclic systems from beta-heteroaryl-beta-methoxyvinyl trihalomethyl ketones

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Sodium salts of acylhydrazones of 1,3 - dioxocompounds and their acylation

Cited by 27 publications

References 4 publications

Correction to Withdrawn Article[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Correction to Withdrawn Article[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Recyclizations of 2‐aminobenzylimines and thioaroylhydrazones of N‐substituted N‐hydroxy‐3‐oxobutanamides

Regiospecific synthesis of new non-condensed heteropolycyclic systems from beta-heteroaryl-beta-methoxyvinyl trihalomethyl ketones

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Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether