Synthesis of 5-Substituted 3-Amino-1H-Pyrazole-4-Carbonitriles as Precursors for Microwave Assisted Regiospecific Syntheses of Pyrazolo[1,5-a]Pyrimidines

Al-Qalaf, Fawzia; Mandani, Faisal; Abdelkhalik, Mervat Mohammed; Bassam, Abeer Abdulrahman

doi:10.3390/molecules14010078

Cited by 19 publications

(6 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that although a common pattern should be expected in the synthesis of pyrazolo[1,5a]pyrimidines from 5-aminopyrazoles, usually different products may result from rather similar conditions [129]. Cyclocondensation of 5-aminopyrazoles with dielectrophiles are two-step reactions, where one of the nitrogen atoms should react firstly, followed by the second one, succeeding the elongation of the side-chain.…”

Section: Intramolecular Cyclization Of 3(5)-aminopyrazolementioning

confidence: 98%

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

2019

View full text Add to dashboard Cite

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.

show abstract

Section: Intramolecular Cyclization Of 3(5)-aminopyrazolementioning

confidence: 98%

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

2019

View full text Add to dashboard Cite

show abstract

“…Al-Qalaf et al sought to utilize unsymmetrical carbonyl compounds such as enaminones and enaminonitriles and explore their potential to carry out similar reactions with aminopyrazole species. [64] The use of symmetrical diketones posed limitations by forming inseparable mixtures of regioisomers due to the presence of two equally reactive electrophilic centers. The stipulated reaction protocol overcame the above limitation and eliminated the possibility of the formation of inseparable regioisomers and generated pyrazolo [1,5-a]pyrimidines derivatives selectively.…”

Section: Synthesis Of Pyrazolopyrimidine Using Microwave Irradiation (Mwi)mentioning

confidence: 99%

Efficient Green Protocols for the Preparation of Pyrazolopyrimidines

et al. 2021

View full text Add to dashboard Cite

Pyrazolopyrimidine with all its isoforms occupy a noteworthy position in medicinal chemistry owing to their proven dominance in the modulation of a vast array of biological receptors, thereby mitigating numerous pathological conditions. The development of sustainable protocols, which integrate the principles of green chemistry in the synthesis process although challenging, offers the most appropriate way to conduct the sustainable synthesis of pyrazolopyrimidines. Due to the effectiveness of this nucleus and striking similarity to purines, they have been accessed using green as well as non-green protocols. Analytical techniques like 2D NMR has been employed for the confirmation of pyrazolopyrimidines and their isomers besides the conventional single-crystal X-ray diffraction (XRD). Here, considering the rising awareness of sustainable protocols, we aimed at exploring this decade for green protocols for the synthesis of pyrazolopyrimidines and furnished products in excellent yields in this review. Protocols covered in this review include synthesis using green solvent, solvent-free conditions, green catalyst, and catalyst-free reactions. Also, synthesis of pyrazolopyrimidines assisted by microwave and ultrasound, as well as ionic liquid mediated synthesis are covered. It is estimated that this review shall throw some light upon the environmentally benign protocols to produce pyrazolopyrimidines which is itself a very important nucleus in the field of medicinal chemistry.

show abstract

“…The huge interest in such MCRs during the last years has been oriented towards developing combinatorial chemistry procedures, because of their high efficiency and convenience in comparison to multistage procedures. Additionally, the utility of MCRs under microwave irradiation (MWI) in the synthesis of heterocyclic compounds enhanced reaction rates and improved regioselectivity [ 21 , 22 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted One Pot Three-Component Synthesis of Novel Bioactive Thiazolyl-Pyridazinediones as Potential Antimicrobial Agents against Antibiotic-Resistant Bacteria

et al. 2021

View full text Add to dashboard Cite

Pyridazine and thiazole derivatives have various biological activities such as antimicrobial, analgesic, anticancer, anticonvulsant, antitubercular and other anticipated biological properties. Chitosan can be used as heterogeneous phase transfer basic biocatalyst in heterocyclic syntheses. Novel 1-thiazolyl-pyridazinedione derivatives were prepared via multicomponent synthesis under microwave irradiation as ecofriendly energy source and using the eco-friendly naturally occurring chitosan basic catalyst with high/efficient yields and short reaction time. All the prepared compounds were fully characterized by spectroscopic methods, and their in vitro biological activities were investigated. The obtained results were compared with those of standard antibacterial/antifungal agents. DFT calculations and molecular docking studies were used to investigate the electronic properties and molecular interactions with specific microbial receptors.

show abstract

Synthesis of 5-Substituted 3-Amino-1H-Pyrazole-4-Carbonitriles as Precursors for Microwave Assisted Regiospecific Syntheses of Pyrazolo[1,5-a]Pyrimidines

Cited by 19 publications

References 20 publications

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

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

Efficient Green Protocols for the Preparation of Pyrazolopyrimidines

Microwave-Assisted One Pot Three-Component Synthesis of Novel Bioactive Thiazolyl-Pyridazinediones as Potential Antimicrobial Agents against Antibiotic-Resistant Bacteria

Contact Info

Product

Resources

About