Regioselective synthesis of functionalized pyrazole-chalcones via a base mediated reaction of diazo compounds with pyrylium salts

2021 ◽  
Author(s):  
Lalita Devi ◽  
Gaurav Sharma ◽  
Ruchir Kant ◽  
Sanjeev K. Shukla ◽  
Namrata Rastogi
Keyword(s):  
Regioselective Synthesis ◽  
Diazo Compounds ◽  
Pyrylium Salts ◽  
Tautomeric Mixture

A base-mediated reaction of triaryl/alkyl pyrylium tetrafluoroborate salts with α-diazo-phosphonates, sulfones and trifluoromethyl compounds affords the corresponding functionalized pyrazole-chalcones as 5-P-5 and 3-P-3 tautomeric mixture.

Silver-mediated synthesis of novel 3-CF3/CN/phosphonate-substituted pyrazoles as pyrrolomycin analogues from 3-formylchromones and diazo compounds

2019 ◽  
Vol 6 (11) ◽  
pp. 1775-1779 ◽  
Author(s):  
Xiaofeng Peng ◽  
Xiaofei Zhang ◽  
Shunyao Li ◽  
Yunfu Lu ◽  
Lefu Lan ◽  
...  
Keyword(s):  
Regioselective Synthesis ◽  
Diazo Compounds ◽  
Substituted Pyrazoles

Herein, a simple and regioselective synthesis of (2-hydroxyphenyl)(3-(trifluoromethyl/cyano/phosphonate)-1H-pyrazol-5-yl)methanones as pyrrolomycin analogues was reported.

Highly Regioselective Synthesis of 3,5-Substituted Pyrazoles from Bromovinyl Acetals and N-Tosylhydrazones

Synlett ◽  
2020 ◽  
Vol 31 (12) ◽  
pp. 1172-1176
Author(s):  
Phannarath Phansavath ◽  
Virginie Ratovelomanana-Vidal ◽  
Anne Westermeyer ◽  
Quentin Llopis ◽  
Gérard Guillamot
Keyword(s):  
Regioselective Synthesis ◽  
Diazo Compounds ◽  
Dipolar Cycloaddition ◽  
Substituted Pyrazoles

A regioselective synthesis of 3,5-disubstituted pyrazoles was achieved by 1,3-dipolar cycloaddition of diazo compounds, generated in situ from N-tosylhydrazones, with unactivated bromovinyl acetals, which served as alkyne surrogates. The reaction tolerated N-tosylhydrazones bearing various substituted benzylidene groups, and a range of 3,5-disubstituted pyrazoles were obtained in yields of up to 92%.

Regioselective synthesis of multisubstituted isoquinolones and pyridones via Rh(iii)-catalyzed annulation reactions

2015 ◽  
Vol 51 (97) ◽  
pp. 17277-17280 ◽  
Author(s):  
Liangliang Shi ◽  
Ke Yu ◽  
Baiquan Wang
Keyword(s):  
Regioselective Synthesis ◽  
Diazo Compounds

A mild and efficient Rh(iii)-catalyzed regioselective synthesis of isoquinolones and pyridones from N-methoxybenzamide or N-methoxymethacrylamide and diazo compounds has been developed, through tandem C–H activation, cyclization, and condensation.

4-(azulen-1-yl)-2,6-diphenylchalcogenopyrylium Perchlorates; Synthesis and Characterization

2020 ◽  
Vol 71 (6) ◽  
pp. 89-95
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin Draghici ◽  
Victorita Tecuceanu ◽  
Maria Maganu ◽  
...  
Keyword(s):  
Synthesis And Characterization ◽  
Pyrylium Salts ◽  
Chloro Derivatives

2,6-Diphenyl substituted thio- and seleno-pyrylium salts with azulen-1-yl moieties in 4-position were prepared from phenylacetylene going through chalcogenopyrones and 4-chloro-chalcogenopyrylium salts as intermediates. The final step of synthesis involves the electrophile substitution in 1-position of azulenes with the obtained chloro-derivatives and the products isolation as stable perchlorates. The electronic and magnetic spectra of products are presented and compared with those of the corresponding pyrylium salts.

Some Considerations Regarding the 1H and 13C Spectra of 4-(1-azulenyl)-2,6-bis(2-heteroaryl-vinyl)- pyrylium and Pyridinium and their Corresponding Pyridines

2018 ◽  
Vol 69 (1) ◽  
pp. 64-69
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin C. Draghici ◽  
Alexandru C. Razus
Keyword(s):  
Double Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Pyridinium Salts ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Pyrylium Salts

The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.

Regioselective Synthesis of Functionalized Oxime Ethers

2010 ◽  
Vol 7 (6) ◽  
pp. 479-482 ◽  
Author(s):  
Jun Liu ◽  
Dafeng Li ◽  
Jian Li ◽  
Chunju Li ◽  
Xueshun Jia
Keyword(s):  
Regioselective Synthesis
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