Three-component synthesis of new o-hydroxyphenyl-substituted pyrazolo[3,4-b]pyridines promoted by FeCl3

Yao, Chaochao; Shu, Miaomiao

doi:10.1515/hc-2015-0234

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…Fan et al demonstrated the FeCl 3 -catalyzed three-component one-pot synthesis of pyrazolo [3,4-b]pyridines 557 in good yields by reacting ethyl 4,4,4-trifluoro-3-oxobutanoate 1 with substituted salicylic aldehydes 489 and 5-amino-3-methyl-1phenylpyrazole 516 (Scheme 196). [300] Modest reaction conditions and wide substrate scope were some of the advantages of this protocol.…”

Section: Other Fused and Bridgehead Heterocyclesmentioning

confidence: 99%

Trifluoromethyl‐β‐dicarbonyls as Versatile Synthons in Synthesis of Heterocycles

Sumran,

Jain,

Kumar

et al. 2024

Chemistry A European J

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Trifluoromethyl group relishes a privileged position in the realm of medicinal chemistry because its incorporation into organic molecules often enhances the bioactivity by altering pharmacological profile of molecule. Trifluoromethyl‐β‐dicarbonyls have emerged as pivotal building blocks in synthetic organic chemistry due to their facile accessibility, stability and remarkable versatility. Owing to presence of nucleophilic and electrophilic sites, they offer multifunctional sites for the reaction. This review covers a meticulous exploration of their multifaceted role, encompassing an in‐depth analysis of mechanism, extensive scope, limitations and wide‐ranging applications in diverse organic synthesis, covering the literature from the 21st century. This comprehensive review encapsulates the applications of trifluoromethyl‐β‐dicarbonyls and their synthetic equivalents as precursors of complex and diverse heterocyclic scaffolds, fused heterocycles and spirocyclic compounds having medicinal and material importance. Their potent synthetic utility in cyclocondenation reactions with binucleophiles, cycloaddition reactions, C‐C bond formations, asymmetric multicomponent reactions using classical/solvent‐free/catalytic synthesis have been presented. Influence of unsymmetrical trifluoromethyl‐β‐diketones on regioselectivity of transformation is also reviewed. This review will benefit the synthetic and pharmaceutical communities to explore trifluoromethyl‐β‐dicarbonyls as trifluoromethyl building blocks for fabrication of heterocyclic scaffolds having implementation into drug discovery programs in the imminent future.

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Section: Other Fused and Bridgehead Heterocyclesmentioning

confidence: 99%

Trifluoromethyl‐β‐dicarbonyls as Versatile Synthons in Synthesis of Heterocycles

Sumran,

Jain,

Kumar

et al. 2024

Chemistry A European J

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“…Recently the reaction of β-ketoesters 81 as in the three-component reaction with 5-aminopyrazoles 16 and substituted salicylic aldehydes 83 was also studied by Fan et al [ 69 ] . An extensive survey of catalysts and solvents identified 0.2 equivalents of FeCl 3 and ethanol as optimal catalyst and solvent, respectively, with which o -hydroxyphenylpyrazolo[3,4- b ]pyridine derivatives 85 were obtained in 89% yields with no formation of the cyclized isomer chromenopyrazolo[3,4- b ]pyridine 86 .…”

Section: Reviewmentioning

confidence: 99%

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

Aggarwal

Kumar

2018

Beilstein J. Org. Chem.

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The condensation of 5-aminopyrazole with various bielectrophilic moieties results in the formation of pyrazoloazines, an interesting array of fused heterocyclic systems. The development of new synthetic routes towards pyrazoloazines for their biological and medicinal exploration is an attractive area for researchers throughout the world. The present review focuses on various synthetic methods developed in the last decade for the synthesis of differently substituted pyrazoloazines by a broad range of organic reactions by means of 5-aminopyrazole as a precursor. ReviewPyrazole and its derivatives are known to exhibit significant biological and pharmacological activities such as: anticancer [1,2], anti-inflammatory [3,4], antioxidant [5], antibacterial [6][7][8], analgesic [9], antiviral [10,11], antimicrobial [12,13], antifungal [6], antiglycemic [14], antiamoebic [15] and antidepressive [16,17]. Considering the immense biological properties pyrazole is one of the most widely studied nitrogen-containing heterocyclic nuclei. Fused pyrazole derivatives are composed of the pyrazole nucleus attached to other heterocyclic moieties which enable them to exhibit improved pharmacological activities compared to the isolated fragments. These compounds are currently used in several marketed drugs like cartazolate (1), zaleplon (2), sildenafil (3), allopurinol (4), indiplon (5), etazolate (6) etc. (Figure 1). Fused pyrazole derivatives, especially pyrazoloazines have been reported to mimic purine bases, present in DNA and RNA, due to close structural resemblance.In addition to the immense biological potential related to fused pyrazoles, their synthetic potential needs to be reviewed for further improvements and extension of interests. Various efforts have been developed for the synthesis of pyrazole-based fused heterocycles. 5-Aminopyrazoles have been extensively employed as useful synthons in designing and constructing a Beilstein J. Org. Chem. 2018, 14, 203-242. 204 A number of review articles have been published by us and others highlighting the synthetic and biological aspects of 5-aminopyrazoles [26][27][28] as well as on the synthesis of fused pyrazole derivatives [25]. However, a perusal of literature reveals that the importance of 5-aminopyrazoles as synthetic precursors for fused heterocycles has not been reported till now to the best of our knowledge. Recent literature shows resurgence of interest in the chemistry and bioactivity of 5-aminopyrazole derivatives leading to improvements in several already known reactions and syntheses of various fused heterocyclic derivatives with various biological activities. Considering the synthetic importance of 5-aminopyrazoles and synthesis of fused pyrazole derivatives with the need for a more general collection, herein we report an exhaustive overview of the main developments in the last decade in the chemistry of 5-aminopyrazoles for the design and synthesis of fused pyrazoloazines.The typical reactivity of 5-aminopyrazoles 5-Aminopyrazoles are polyfunctional co...

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“…When 5-amino-3-methyl-1-phenylpyrazole ( 21 ) reacted with aldehydes 1 and other CH-acids (acetoacetic acid derivatives), e.g., 98e,f (Fan et al, 2016 ), 3-oxo-3-phenylpropanenitrile 107 (Huang et al, 2011 ; Rahmati and Khalesi, 2012 ) heteroaromatic pyrazolopyridines 128 (similar to compounds 126 ) and 129 (similar to compounds 118a , Figure 8 ) were formed (Figure 10 ).…”

Section: Main Partmentioning

confidence: 99%