Efficient synthesis and dehydration reaction of trichloromethylated 2‐(3‐phenyl‐5‐hydroxy‐4,5‐dihydro‐1<i>H</i>‐pyrazol‐1‐yl)‐4‐aryl‐5‐alkylthiazoles

Bonacorso, Hélio G.; Muniz, Mauro Neves; Wastowski, Arci Dirceu; Zanatta, Nilo; Martins, Marcos A. P.

doi:10.1002/hc.10113

Cited by 9 publications

(2 citation statements)

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“…It is important to note that the electron‐withdrawing effect caused by the thiocarboxyamide hinders the elimination of water and subsequent aromatization of the 5‐membered ring [31] . The thiocarboxyamide moiety was reacted with 2‐bromophenones (EtOH, 24 h, reflux) to furnish thiazole–pyrazoline conjugated heterocycles 10 at good yields (65–94 %, Scheme 4a) [32] …”

Section: Synthesis Of Pyrazolines and Pyrazoles Using Nn‐dinucleophilesmentioning

confidence: 99%

Haloacetylated Enol Ethers: a Way Out for the Regioselective Synthesis of Biologically Active Heterocycles

2021

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This review describes advances in the synthesis of heterocyclic scaffolds (associated with their biological activity), using haloacetylated enol ethers as precursors. The wide variety of heterocycles that can be prepared using these precursors, together with the high regioselectivity they usually provide, in [3+2] and [3+3] cyclocondensation reactions, make these starting materials powerful tools. The biological evaluation is also highlighted, given that several analogues of commercially available drugs can be easily accessed.

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Section: Synthesis Of Pyrazolines and Pyrazoles Using Nn‐dinucleophilesmentioning

confidence: 99%

Haloacetylated Enol Ethers: a Way Out for the Regioselective Synthesis of Biologically Active Heterocycles

2021

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“…In this case, only one isoxazoline and one 2-pyrazoline have been isolated. In particular, the synthetic potential of β-alkoxyvinyl trihalomethyl ketones to obtain series of novel heterocycles of five, 18 six, 19 seven membered rings 20 and more recently bisheterocyles 21 has been reported by us. Considering the biological importance of 2-pyrazolines and the fact that trichloromethylated analogs, such as, bisheteroaryl ketones are not yet known, it would be nice to demonstrate a new synthetic application of β-heteroaryl-β-methoxyvinyl trihalomethyl ketones.…”

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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Efficient Synthesis and Dehydration Reaction of Trichloromethylated 2‐(3‐Phenyl‐5‐hydroxy‐4,5‐dihydro‐1H‐pyrazol‐1‐yl) ‐4‐aryl‐5‐alkylthiazoles (III).

et al. 2003

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Efficient synthesis and dehydration reaction of trichloromethylated 2‐(3‐phenyl‐5‐hydroxy‐4,5‐dihydro‐1H‐pyrazol‐1‐yl)‐4‐aryl‐5‐alkylthiazoles

Abstract: A convenient method for the synthesis of a novel

Cited by 9 publications

References 27 publications

Haloacetylated Enol Ethers: a Way Out for the Regioselective Synthesis of Biologically Active Heterocycles

Haloacetylated Enol Ethers: a Way Out for the Regioselective Synthesis of Biologically Active Heterocycles

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

Efficient Synthesis and Dehydration Reaction of Trichloromethylated 2‐(3‐Phenyl‐5‐hydroxy‐4,5‐dihydro‐1H‐pyrazol‐1‐yl) ‐4‐aryl‐5‐alkylthiazoles (III).

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