- “On-water” one-pot four-component synthesis of novel 1H-furo[2,3-c]pyrazole-4-amine derivatives
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A catalyst-free, simple and green protocol has been accomplished for the synthesis of novel 1H-furo[2,3-c]pyrazole-4-amines in a one-pot four-component domino reaction involving hydrazines, ethyl acetoacetate, aromatic amines and phenylglyoxal monohydrate in water. The protocol presented herein describes in situ generated pyrazolone as intermediate reactants with phenylglyoxal monohydrate in a Knoevenagel condensation followed by a Michael addition of amine, intramolecular cyclization, dehydration and the resulting to the title compound. It was observed that in this protocol bis(pyrazole-5-ols) are formed with amines bearing strong electron withdrawing groups under similar reaction conditions instead of the expected products. The reaction merits the use of water as solvent, no additive catalyst, easy workup, easy purification of products by non-chromatography and provides high yield of products with good purity.
- Noruzian, Fatemeh,Olyaei, Abolfazl,Hajinasiri, Rahimeh
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p. 4383 - 4394
(2019/05/01)
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- 3-methyl-4-substituted benzylidene pyrazol-5-ones: Synthesis, evaluation of antinociceptive activities and in silico studies
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A series of 3-methyl-4-substituted benzylidene pyrazol-5-ones were subjected to molecular docking studies using targets involved in nociception such as COX-2, TRPV1, P2X3 and glutamate to explore the structural features necessary for interactions with the active site of amino acids in various biological targets. Molecular docking studies showed that the introduction of electron releasing groups on benzylidene ring seem to enhance the binding affinity of pyrazolones. Compounds M2 (4-hydroxy) and M8 (3,4-dimethoxy) showed good binding affinity for TRPV1 and P2X3 receptors, whereas compound M9 (3,4,5-trimethoxy) was found to be favorable for COX-2 and glutamate receptors. These compounds were synthesized and evaluated using capsaicin, ATP and glutamate induced nociception to study the effect of title compounds on TRPV1, purinergic and glutamate receptors, respectively at a dose of 150 mg/kg body weight. Compounds M6 (3,4-dichlro) and M8 (3, 4-dimethoxy) displayed good antinociceptive activity in TRPV1 and ATP induced nociception models whereas, compound M9 (3, 4, 5-trimethoxy) exhibited promising activity in glutamate-induced nociception. Some of the synthesized compounds bearing unsubstituted 4-hydroxy-2,3-dimethoxy and 4-dimethylamino benzylidene ring (M1-M4) have been earlier reported for their antinociceptive activity in acetic acid induced writhing and tail immersion methods. The results of the present study implicated that the compounds possessing 4-hydroxy and 4-dimethylamino groups showed good antinociceptive activity in all the models. The results might be useful to design and develop pyrazolones as potential antinociceptive agents.
- Swapna,Begum, Shaheen,Begum, Arifa,Bharathi,Sujatha
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p. 2107 - 2115
(2018/08/09)
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- Synthesis and bioactivity evaluation of pyrazolone derivatives
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3-Methyl-4-substituted benzylidene-pyrazol-5-ones 1-10 are synthesized by the condensation of 3-methyl-pyrazol-5-one with substituted aliphatic and aromatic aldehydes. Their structures have been elucidated from UV-Vis, IR, 1H NMR and mass spectral data. Among the synthesized derivatives 5, 6, 7 and 10 are found to have a potent anti-inflammatory response whereas compounds 1, 4, 5, 8 and 10 have an effective analgesic response. There is no remarkable difference in bioactivity of pyrazolones derived from aliphatic and aromatic aldehydes. All the experimental data are statistically significant at p0.05.
- Mariappan,Saha,Sutharson,Haldar
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experimental part
p. 1671 - 1674
(2011/02/23)
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- Synthesis of some novel ethoxyphthalimide derivatives of pyrazolo[3,4-c]pyrazoles
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The synthesis of 5-methyl-4-substituted benzylidene-2,4-dihydro-3H-pyrazol- 3-one 3a-d is achieved by the condensation reaction of 5-methyl-2,4-dihydro-3H- pyrazol-3-one 1 with 4-substituted benzaldehydes 2a-d. Compound 1 is prepared by the cyclization reaction between ethylacetoacetate and hydrazine hydrate in absolute alcohol. Compounds 3a-d are converted into corresponding ethoxyphthalimide derivatives 5a-d by treatment with phthalimidoxyethyl bromide 4. 1-N-Ethoxyphthlimido-3-methyl-4-(4-substituted benzylidene)pyrazol-5-ones 5a-d are reacted with thiosemicarbazide/NaOH and isoniazid/AcONa/AcOH separately to yield 6-N-ethoxyphthalimido-4-methyl-3-(4-substituted phenyl)-2- thiocarbamoyl-3,3α-dihydro pyrazolo[3,4-c]pyrazoles 6a-d and 6-N-ethoxyphthalimido-2-isonicotinoyl-4-methyl-3-(4-substituted phenyl)-3,3α-dihydro pyrazolo[3,4-c]pyrazoles 7a-d respectively. Structures of the synthesized compounds have been elucidated by means of IR, 1H NMR and mass spectral data.
- Sharma, Chirag,Thadhaney, Bhawana,Pemawat, Gangotri,Ltalesara
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experimental part
p. 1892 - 1897
(2009/05/09)
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- Michael Addition of Ylidenpyrazolones
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The reactivity of ylidenpyrazolones (1a-c) towards compounds bearing an activated double bond has been investigated.Ia on treatment with acrylonitrile furnishes the amide (II) while with ethyl acrylate, N-arylmaleimides and dimethyl acetylendicarboxylate, the Michael adducts (IV-VI) are obtained.The reaction of Ib and Ic with acrylonitrile and ethyl acetate gives the adducts VII.
- Khalifa, Fathy A.,Abdel-Galil, Fathy M.,Riad, Bahia Y.,Elnagdi, Mohamed H.
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p. 1158 - 1159
(2007/10/02)
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