ANRORC rearrangement in tetrahydro-2H-chromenones. Synthesis and structural assignment by NMR, MS, X-ray and DFT calculations of 2-[3(5)-trifluoromethyl-1H-pyrazol-4-yl)arylmethyl]cyclohexenones and derivatives

Bonacorso, Hélio G.; Navarini, Jussara; Porte, Liliane M. F.; Pittaluga, Everton P.; Junges, Andrizia F.; Meyer, Alexandre R.; Martins, Marcos A. P.; Zanatta, Nilo

doi:10.1016/j.jfluchem.2013.03.014

Cited by 15 publications

(2 citation statements)

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“…[130] The desired products 150 were obtained in good yields in a few minutes compared with conventional method (59-75 %) involving heating of 2 h. Bonacorso et al demonstrated an ANRORC rearrangement in 2-trifluoromethyl-tetrahydro-2H-chromenones 151 when treated with hydrazine hydrate 54 for the synthesis of 4functionalized 3(5)-trifluoromethyl-1H-pyrazoles 152 in good yields (Scheme 43). [131] S N (ANRORC) degenerate ring transformation was rationalized through the initial removal of the most acidic proton of the chromenones 151 by the hydrazine hydrate 54, followed by simultaneous opening of pyran ring with generation of two 1,3-dicarbonyl compounds linked to each other by a methylaryl unit in the intermediates ( 151 A-B ). [61] Therein, the authors reported that the aromatic 1H-pyrazole product is isolated as 1,5-tautomer form from NMR CDCl 3 solution analysis data and 1,3-tautomer form from the crystal X-ray diffraction data.…”

Section: Pyrazole Derivativesmentioning

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: Pyrazole Derivativesmentioning

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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show abstract

“…Because of their specialized electronic properties, the chemistry of heterocyclic molecules like pyrones, chromones, and their derivative has generated a new interest in heterocycle synthesis in recent years, namely, they are often involved in domino transformation since the push and pull fragment in pyrone remains labile towards external and internal nucleophiles. [ 19 ] Considering the tendency of chromone framework to undergo an ANRORC (Addition of the Nucleophile, Ring Opening, and Ring Closure) modification with various nucleophiles, [ 20 ] we started exploring the reaction of 3‐acetylene‐chromone with NH 2 OH · HCl.…”

Section: Introductionmentioning

confidence: 99%