Comparative study of the catalytic preparation of flavones using Keggin heteropolyacids under homogeneous, heterogeneous and solvent free conditions

Bennardi, Daniel Oscar; Romanelli, Gustavo Pablo; Autino, Juan Carlos; Pizzio, Luis R.; Vázquez, Patricia; Cáceres, Carmen Victoria; Blanco, Mirta N.

doi:10.1007/s11144-010-0172-4

Cited by 11 publications

(10 citation statements)

References 27 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, we have used Keggin heteropolyacids in a range of processes, i.e., preparation of heterocycles [3,4], protection/deprotection of organic functional groups [5,6] and oxidation processes, as well as substituted phenol, alcohol and amine oxidation, and the selective oxidation of sulfides to sulfoxides with aqueous H 2 O 2 [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Doped Keggin heteropolyacids as catalysts in sulfide oxidation

Palermo

Sathicq

Vázquez

et al. 2011

Reac Kinet Mech Cat

View full text Add to dashboard Cite

In this research, we report the preparation of doped PMo Keggin heteropolyacids where Mo is partially replaced by V, Bi, and Bi-V. These catalysts were characterized by means of ICP-AES analysis, 31 P-NMR, UV-visible spectra, FT-IR spectra, thermal analysis, and textural properties. In addition, the activities of the synthesized catalysts were evaluated in the selective oxidation of sulfides to sulfoxides/sulfones. The incorporation of V, Bi and Bi-V into the structure of H 3 PMo 12 O 40 increases the catalytic activity. The two most active catalysts, those with V and V-Bi were supported on aminopropyl-functionalized silica (SiO 2 NH 2 ) and they were found to be and efficient heterogeneous catalysts for the selective oxidation of diphenylsulfide to the corresponding sulfoxide/sulfone.

show abstract

Section: Introductionmentioning

confidence: 99%

Doped Keggin heteropolyacids as catalysts in sulfide oxidation

Palermo

Sathicq

Vázquez

et al. 2011

Reac Kinet Mech Cat

View full text Add to dashboard Cite

show abstract

“…Therefore, alternative methods for the green synthesis of 2H-1-benzopyrans are needed. In this context, heteropolyacids, which have been successfully evaluated and recovered for the sustainable synthesis of heterocycles such as, coumarins [4], flavones [5], chromones [6], and dihydropyrimidinones [7], may be good catalysts for the reaction.…”

Section: Introductionmentioning

confidence: 99%

Green synthesis of 6-cyano-2,2-dimethyl-2-H-1-benzopyran and its subsequent enantioselective epoxidation

Romanelli¹,

Sathicq²,

Vázquez³

et al. 2015

Journal of Molecular Catalysis A: Chemical

Self Cite

View full text Add to dashboard Cite

a b s t r a c tThe clean synthesis of 6-cyano-2,2-dimethyl-2-H-1-benzopyran epoxide starting from 3-methyl-2-butenal is reported using recyclable catalysts. H 4 PMo 11 VO 40 (PMo 11 V) and (PyH) 3 HPMo 11 VO 40 (Py 3 -PMo 11 V) Keggin-type heteropolyacids were used to synthesize 6-cyano-2,2-dimethyl-2-H-1-benzopyran in two steps with 35% yield. This is an alternative procedure to the traditional methodology with pyridine or picoline as catalyst, where 6-cyano-2,2-dimethyl-2-H-1-benzopyran is obtained by condensation of 4-cyanophenol with 1,1-diethoxy-3-methyl-2-butene. The 6-cyano-2,2-dimethyl-2-H-1-benzopyran epoxide was obtained using Jacobsen-type catalysts, and in situ generated dimethyldioxirane (DMD) as oxidizing agent, that in comparison to m-CPBA/4-NMO and NaOCl/4-PPNO did not degrade the catalyst. In presence of 4-phenylpyridine N-oxide (4-PPNO) at 4 • C, enantioselectivities of 87% for 3S,4S-epoxide and 68% for 3R,4R-epoxide were obtained with the S,S-and R,R-Jacobsen catalysts, respectively. Overall yield was approximately 17% for 3S,4S-epoxide.

show abstract

“…HPAs have been used in a variety of acid-catalysed reactions such as esterification, etherification, olefin hydration and dehydration of alcohols and are also attractive as catalysts for oxidation processes. 16 Recently, we have applied the use of Keggin HPAs in a wide range of processes, i.e., preparation of heterocycles, 17,18 protection/deprotection of organic functional groups 19,20 and oxidation processes, as well as substituted phenol, alcohol and amine oxidation, and the selective oxidation of sulphides to sulphoxides and sulphones. [21][22][23][24] Vanadium-incorporated molybdophosphoric acid catalysts show unique catalytic features for oxidations due to their bifunctional character, which arises because of the redox nature of vanadium and the oxidation/acidic character of molybdophosphoric acid catalysts by replacing Mo atoms with corresponding V atoms.…”

Section: Introductionmentioning

confidence: 99%

Role of vanadium and pyridine in heteropolycompounds for selective oxidation of alcohols with hydrogen peroxide

et al. 2013

View full text Add to dashboard Cite

and a hybrid pyridine-modified heteropolyacid with Keggin structure for selective oxidation of alcohols to ketones or aldehydes using aqueous hydrogen peroxide and acetonitrile as solvent. Performance of these different catalysts in 1-phenylethanol oxidation was studied. Influence of reaction temperature, amount of catalyst and hydrogen peroxide and reaction time on the yield of acetophenone was investigated to obtain optimal reaction conditions. Oxidation ability of the catalyst depended on the number of vanadium atoms present in the Keggin ion and to a lesser extent on pyridine substitution in the Keggin secondary structure. In order to explore the applicability of the method for selective oxidation of alcohols to ketones or aldehydes, various alcohols were investigated according to the general procedure using hybrid pyridine-modified heteropolyacid.

show abstract

Comparative study of the catalytic preparation of flavones using Keggin heteropolyacids under homogeneous, heterogeneous and solvent free conditions

Abstract: Keggin heteropolyacids are found to be selective and recyclable catalysts for the preparation of flavones. The reaction was carried out in different reaction media, homogeneous, heterogeneous and solvent-free conditions. The solvent-free conditions represent the best green conditions.

Cited by 11 publications

References 27 publications

Doped Keggin heteropolyacids as catalysts in sulfide oxidation

Doped Keggin heteropolyacids as catalysts in sulfide oxidation

Green synthesis of 6-cyano-2,2-dimethyl-2-H-1-benzopyran and its subsequent enantioselective epoxidation

Role of vanadium and pyridine in heteropolycompounds for selective oxidation of alcohols with hydrogen peroxide

Contact Info

Product

Resources

About