Synthesis of Pyrazoles via Cul-Mediated Electrophilic Cyclizations of alpha,beta-Alkynic Hydrazones

Synthesis of pyrazoles via electrophilic cyclization of alpha,beta-alkynic hydrazones by copper(I) iodide is described. When treated with copper(I) iodide in the presence of triethylamine in refluxing acetonitrile, alpha,beta-alkynic hydrazones, prepared readily from hydrazines and propargyl aldehydes and ketones, undergo electrophilic cyclization to afford pyrazole derivatives in good to excellent yields. The reaction appears to be general for a variety of alpha,beta-alkynic hydrazones and tolerates the presence of aliphatic, aromatic, and ferrocenyl moieties with electron-withdrawing and electron-donating substituents.


Synthesis of Bishomoinositols and an Entry for Construction of a Substituted 3-Oxabicyclo[3.3.1]nonane Skeleton
BARAN, ARİF; Bekarlar, Merve; Aydin, Gokay; NEBİOĞLU, MEHMET; ŞAHİN, Ertan; Balcı, Metin (2012-02-03)
1,3,3a,7a-Tetrahydro-2-benzofuran was used as key compound for the synthesis of various bishomoinositol derivatives. The diene was subjected to an epoxidation reaction for further functionalization of the diene unit. The bisepoxide obtained was submitted to a ring-opening reaction with acid in the presence of water. Various bishomoinositols were synthesized. However, when the reaction was carried out in the presence of acetic anhydride, a substituted 3-oxabicyclo[3.3.1]nonane skeleton was formed. The mechan...
Synthesis and characterization of a bifunctional amido-thiophene monomer and its copolymer with thiophene and electrochemical properties
AK, M; Çırpan, Ali; Yılmaz, Fatih; YAGCI, Y; Toppare, Levent Kamil (2005-05-01)
A bifunctional amido-thiophene namely hexamethylene (bis-3-thiophene acetamide) (HMTA) was synthesized by the reaction of 3-thiophene acetic acid with hexamethylene diamine. Copolymerization in the presence of thiophene was achieved electrochemically in tetrabutylammonium tetrafluoroborate/acetonitrile (TBAFB/AN). Spectroelectro-chemical analysis of the resulting copolymer [P(HMTA-co-Th)] reflected electronic transitions at 505 nm, 740 nm and similar to 1000 nm, revealing pi to pi* transition, polaron and b...
Synthesis of ferrocene substituted pyrrolidine derivatives via Et2Zn catalyzed 1 3 dipolar cycloaddition reactions of azomethine ylides
Doğan, Özdemir (2001-05-01)
Synthesis of ferrocene substituted pyrrolidine derivatives via diethylzinc catalyzed 1,3-dipolar cycloadditions of azomethine ylides is described. Azomethine ylides were generated from glycine methyl ester and ferrocenecarboxaldehyde by the 'imine tautomerization' method and trapped with dipolarophiles to give the corresponding cycloadducts in reasonable yields and high regio- and stereoselectivity.
Synthesis and biological evaluation of optically active conjugated gamma- and delta-lactone derivatives
ŞARDAN, Melis; Sezer, Serdar; GUNEL, Aslihan; AKKAYA, MAHİNUR; Tanyeli, Cihangir (2012-09-15)
An efficient synthesis of racemic and both enantiomeric forms of heteroaryl substituted gamma- and delta-lactone derivatives derived from allyl and homoallyl alcohol backbones has been accomplished via ring closing metathesis reaction. 2-Heteroaryl substituted allyl and homoallyl alcohols have been efficiently resolved through enzymatic method with high ee (97-99%) and known stereochemistry. Antimicrobial and antioxidant activities of target lactones were evaluated.
Synthesis of 1,2,3,5- tetrasubstituted pyrrole derivatives via 5-exo-dig type cyclization and stereoselective functionalisation of ferrocene derivatives
Kayalar, Metin; Demir, Ayhan Sıtkı; Department of Chemistry (2005)
A convenient and new method for the synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives starting from 1,3,-dicarbonyl compounds through acid catalyzed cyclization reaction is described. Alkylation of 1,3-dicarbonyl compound with propargyl bromide followed by one step cyclization with the introduction of primary amines in the presence of catalytic amount of triflouroacetic acid (TFA) affords the corresponding pyrrole derivatives in high yields. The investigations on the studies of developing a new meth...
Citation Formats
M. Zora, “Synthesis of Pyrazoles via Cul-Mediated Electrophilic Cyclizations of alpha,beta-Alkynic Hydrazones,” JOURNAL OF ORGANIC CHEMISTRY, pp. 9379–9390, 2011, Accessed: 00, 2020. [Online]. Available: