Studies on Azopyrazole Derivatives, VI<sup>1)</sup>. Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N<sup>2</sup>‐(substituted benzylidene) benzohydrazides

Av ariety of multisubstituted azopyrazoles were synthesized in good yield from an efficient onepot silver trifluoromethanesulfonate (AgOTf)-catalyzed cascade reactiono fa-diazo-b-keto esters with two arylhydrazines or twoa rylhydrazine hydrochlorides.T his cascade reactioni ncluded pyrazolone formation, N À Hi nsertion, and oxidation. Fort he synthesis of more diverse azopyrazoles bearing two different aromatic rings,t he silver(I)-catalyzed cascade reactiono f4 -diazopyrazol-3-one with arylhydrazine hydrochloridesw as also developed. Thea dvantages of these methodologies are easy handling, mild reaction conditions,a nd an effective and non-toxic catalyst usage.

show abstract

Construction of Multifunctionalized Azopyrazoles by Silver‐ Catalyzed Cascade Reaction of Diazo Compounds

Pandit

Lee

2015

Adv Synth Catal

View full text Add to dashboard Cite

show abstract

Synthesis and Characterization of New 1,3,4‐Oxadiazolines Synthese und Charakterisierung neuer 1,3,4‐Oxadiazoline

Ergenç

Rollas

Topaloglu

et al. 1989

Archiv der Pharmazie

View full text Add to dashboard Cite

In connection with our previous research on the synthesis of azo-substituted five membered heterocycles'") we repon here the synthetic route and the spectral characteristics of 2-aryl substituted-3-acetyl-5-[4-( 1 -phenyl-3,5-dimethyl-4-pyrazoly1azo)-phenyll-1,3,4-oxadiazolines 2a-2h. 4-( 1 -Phenyl-3.5-dimethylpyrazoly1azo)-N2-(substituted benzylidene)benzohydrazides la-lhSe8), obtained from the reaction of 1 -phenyl-3,5-dimethyl-4-(4-hydrazinocarbonylphenylazo)-pyrazole (1)9' with various aldehydes, were reacted with Ac20, but no acetyl derivatives of hydrazones were formed, instead, cyclization occured and compounds 2a-2h were obtained (Scheme).The structures of compounds 2a-2h were confirmed by means of elemental analysis and spectral data. Instead of the UV absorptions of la-lh between 348-352 run, 2a-2h showed maxima between 359-367 run. The NH-absorptions of la-lh occured at about 3200 cm", whereas 2a-2h had PhCompound 1 ArCHO I no absorptions in this region. Because both the starting compounds la-lh and the cyclization products 2a-2h have carbonyl functionalities the ab sorptions of 2a-2h at 1654-1674 cm-' (compounds 2b and 2c showed an additional C=O absorption at 1769 cm-' due to the acetylation of the OH group of the aromatic ring) could not help in structure elucidation. The 5-substituted-3-acetyloxadiazoline structure was supported by the 'H-NMR spectra of 2a-2h. Signals due to -CONH-N= at about 12 ppm disappeared after cyclization. Furthermore, the Ar-CH=N-protons of la-lh which show a one proton singlet at about 8.10-8.70 ppm region were shifted to the 7.06-7.13 ppm region. Although this proton would be expected at a little bit higher field, the inductive effect of 0 and N and the phenyl ring attached to the same C-atom shift this one proton signal more downfield than expected.The molecular structure of the compounds was further elucidated by EI-MS data. Molecular ions at m/z = 566; 508: 498; 482; 509 and 507 confirmed the molecular weights of 2c-2h, respectively. M' of 2a was not detec-

show abstract

ChemInform Abstract: Studies on Azopyrazole Derivatives. Part 6. Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N2‐(substituted Benzylidene)benzohydrazides.

Ergenç¹,

Rollas²,

Topaloglu³

1986

Chemischer Informationsdienst

View full text Add to dashboard Cite

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

hi@scite.ai

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Studies on Azopyrazole Derivatives, VI¹⁾. Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N²‐(substituted benzylidene) benzohydrazides

Abstract: The synthesis of the title compounds 1-5 from l-phenyl-3,5-dimethyl-4-[4-(hydrazinocarbonyl)phenylazo]pyrazole2) and various aldehydes is reported.

Cited by 5 publications

References 2 publications

Construction of Multifunctionalized Azopyrazoles by Silver‐ Catalyzed Cascade Reaction of Diazo Compounds

Construction of Multifunctionalized Azopyrazoles by Silver‐ Catalyzed Cascade Reaction of Diazo Compounds

Synthesis and Characterization of New 1,3,4‐Oxadiazolines Synthese und Charakterisierung neuer 1,3,4‐Oxadiazoline

ChemInform Abstract: Studies on Azopyrazole Derivatives. Part 6. Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N2‐(substituted Benzylidene)benzohydrazides.

Contact Info

Product

Resources

About

Studies on Azopyrazole Derivatives, VI1). Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N2‐(substituted benzylidene) benzohydrazides

Abstract: The synthesis of the title compounds 1-5 from l-phenyl-3,5-dimethyl-4-[4-(hydrazinocarbonyl)phenylazo]pyrazole2) and various aldehydes is reported.

Cited by 5 publications

References 2 publications

Construction of Multifunctionalized Azopyrazoles by Silver‐ Catalyzed Cascade Reaction of Diazo Compounds

Construction of Multifunctionalized Azopyrazoles by Silver‐ Catalyzed Cascade Reaction of Diazo Compounds

Synthesis and Characterization of New 1,3,4‐Oxadiazolines Synthese und Charakterisierung neuer 1,3,4‐Oxadiazoline

ChemInform Abstract: Studies on Azopyrazole Derivatives. Part 6. Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N2‐(substituted Benzylidene)benzohydrazides.

Contact Info

Product

Resources

About

Studies on Azopyrazole Derivatives, VI¹⁾. Synthesis and Characterization of New 4‐(1‐Phenyl‐3,5‐dimethylpyrazolylazo)‐N²‐(substituted benzylidene) benzohydrazides