Synthesis of Some Pyrimidine, Pyrazole, and Pyridine Derivatives and Their Reactivity Descriptors

El‐Sattar, Nour E. A. Abd; Badawy, Eman H. K.; Abdel‐Mottaleb, M. S. A.

doi:10.1155/2018/8795061

Cited by 16 publications

(12 citation statements)

References 21 publications

(22 reference statements)

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“…For this reason, our focus in this review is on the chemical potential of 3(5)-aminopyrazoles in heterocyclic synthesis. As stated by El-Sattar et al, the chemical potential of a compound reflects the relationship between its structure and reactivity, thus a comparatively higher chemical potential of a compound means a higher reactivity [115]. In compounds that exhibit tautomerism, the reactivity may be controlled by a particular tautomeric form and, according to the Gustafsson paradox, the less abundant tautomer tends to be the most reactive one [116].…”

Section: (5)-aminopyrazole In Heterocyclic Synthesismentioning

confidence: 99%

“…In these circumstances, a paramount need to elucidate the precise chemical potential of the entities present in a specific reactant mixture emerges. HOMO and LUMO states and energies of the tautomeric structures represent the parameters that mostly contribute to their chemical potential; as such, variations alter the acidic/basic and electrophilic/nucleophilic properties of the compounds [85,115]. It was already shown that in heterocycles, including 3(5)-aminopyrazoles, the different characteristics of molecular orbitals promote distinct reactivities of each of the tautomeric species [66,85].…”

Section: (5)-aminopyrazole In Heterocyclic Synthesismentioning

confidence: 99%

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Revisiting the Structure and Chemistry of 3(5)-Substituted Pyrazoles

2019

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Pyrazoles are known as versatile scaffolds in organic synthesis and medicinal chemistry, often used as starting materials for the preparation of more complex heterocyclic systems with relevance in the pharmaceutical field. Pyrazoles are also interesting compounds from a structural viewpoint, mainly because they exhibit tautomerism. This phenomenon may influence their reactivity, with possible impact on the synthetic strategies where pyrazoles take part, as well as on the biological activities of targets bearing a pyrazole moiety, since a change in structure translates into changes in properties. Investigations of the structure of pyrazoles that unravel the tautomeric and conformational preferences are therefore of upmost relevance. 3(5)-Aminopyrazoles are largely explored as precursors in the synthesis of condensed heterocyclic systems, namely pyrazolo[1,5-a]pyrimidines. However, the information available in the literature concerning the structure and chemistry of 3(5)-aminopyrazoles is scarce and disperse. We provide a revision of data on the present subject, based on investigations using theoretical and experimental methods, together with the applications of the compounds in synthesis. It is expected that the combined information will contribute to a deeper understanding of structure/reactivity relationships in this class of heterocycles, with a positive impact in the design of synthetic methods, where they take part.

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Section: (5)-aminopyrazole In Heterocyclic Synthesismentioning

confidence: 99%

Section: (5)-aminopyrazole In Heterocyclic Synthesismentioning

confidence: 99%

Revisiting the Structure and Chemistry of 3(5)-Substituted Pyrazoles

2019

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“…Density Functional Theory (DFT) was used to determine the equilibrium structure using ab initio levels to support these results. The calculations were performed using the Gaussian 09 package [ 20 ]. Minimum energy-optimized structures for each PFO were obtained by ab initio density functional theory (DFT).…”

Section: Methodsmentioning

confidence: 99%

Intermolecular CH-π Electrons Interaction in Poly (9,9-dioctylfluorenyl-2,7-diyl) (PFO): An Experimental and Theoretical Study

2022

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This study demonstrates the presence of CH-π interaction in poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO-1) due to an aggregate formation of PFO-1 in the liquid state. The absorption spectra of PFO-1 in certain solvents at low concentrations showed a single band at 390 nm. However, when using high concentrations, a new band at 437 nm appeared. This band is due to the aggregate formation of PFO-1. The aggregate formation occurs as a result of the CH interaction of the n-alkyl side chains with π-electrons in the benzene ring. The optical characteristics of another conjugated polymer of poly [9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl] (PFO-2) were investigated to confirm the CH-π interaction. The absorption showed only one wavelength at 390 nm without any new band at the end of the spectrum, even at higher concentrations and lower temperatures. The main reason for the absence of aggregate formation in PFO-2 is the sterical hindrance caused by the branched alkyl side chains. In addition, Density Functional Theory (DFT) was used to compute the HOMO–LUMO transitions, electron charge distribution, and frontier molecular orbitals for each polymer. The Mulliken charge distribution and demonstrated a notable difference in the reactivity of the alkyl side chain, confirming the higher ability of PFO-1 to form CH-π bonds. docking model emphasized that the band at 437 nm could be attributed to the interaction between CH in the n-alkyl side chain and π bonds in the aromatic rings of PFO-1.

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“…Chalcones transformation might proceed either by 1,4-addition or 1,2-addition. Examples of heterocyclic compounds from chalcones are pyrazoles [1,2], pyrroles [3][4][5], pyrazoline [6], isoxazoles [7][8][9], pyrimidines [10,11], pyridines [12][13][14][15][16], indoles, indazoles, triazoles [17,18], imidazoles [19,20], thiazines [21], 1,5-benzodiazepines, 1,3,4-thiadiazepines, benzoazepines, and 1,5-benzodiazepines [22]. Chalcones are multifunctional molecules that possess promising pharmacological activities.…”

Section: Introductionmentioning

confidence: 99%

“…-b]pyridines 72[15]. While Abd El-Sattar et al reported pyridine 74 from chalcone 73 and malononitrile[16] (Scheme 12).…”

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confidence: 99%

Recent Advances in Chalcones: Synthesis, Transformation and Pharmacological Activities

Ovonramwen

Owolabi

Oviawe

2019

AJOCS

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Chalcones are useful intermediates in the synthesis of heterocyclic compound and the unique reagents in organic synthesis. The usual approach to obtain chalcones is through Claisen-Schmidt condensation. Several novel heterocyclic chalcone analogs have emerged. Chalcones are multifunctional molecules that possess promising pharmacological activities. Chalcones are known for anti-cancer, antioxidant, anti-inflammatory, anti-microbial, anti-tubercular, antileishmanial, antimalarial, anthelmintic, osteogenic activities. This review article focuses on recent applications of Claisen-Schmidt condensation reaction employed in the synthesis of chalcone, its transformation to heterocyclic compounds and pharmacological activities.

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Synthesis of Some Pyrimidine, Pyrazole, and Pyridine Derivatives and Their Reactivity Descriptors

Cited by 16 publications

References 21 publications

Revisiting the Structure and Chemistry of 3(5)-Substituted Pyrazoles

Revisiting the Structure and Chemistry of 3(5)-Substituted Pyrazoles

Intermolecular CH-π Electrons Interaction in Poly (9,9-dioctylfluorenyl-2,7-diyl) (PFO): An Experimental and Theoretical Study

Recent Advances in Chalcones: Synthesis, Transformation and Pharmacological Activities

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