Recent Advances in Acid–Base and Solvation Properties of Metal Phenolates

Bastos, E. L.; Machado, Caroline Oliveira

doi:10.1002/9780470682531.pat0848

Cited by 2 publications

(1 citation statement)

References 169 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this context, pure phenol metal salts have been reported only for some simple phenols, including phenol and its alkyl derivatives, resorcinol, and some other simple phenols. [34,[42][43][44] Considering the above, the present work demonstrates our initial approach to the conversion of the simple natural bioactive phenolic compound "thymol" into its corresponding metal/ ammonium salts. Various metal (Na, K, Li, Cu, Zn) and ammonium (tetrabutyl ammonium and choline) salts of thymol have been synthesized and characterized using IR, NMR, TGA, CHN and DSC analysis.…”

Section: Introductionmentioning

confidence: 87%

Bioactive Phenolate Salts: Thymol Salts

Reddy

Domb

2023

ChemMedChem

View full text Add to dashboard Cite

Phenolate salts of bioactive agents have been reported only scarcely. This is the first report on the formation and characterization of thymol phenolate salts as representatives of phenol‐containing bioactive molecules. Thymol has been used in medicine and agriculture for decades owing to its excellent therapeutic properties. However, in light of its poor aqueous solubility, thermal instability, and especially its high chemical volatility, the utility of thymol is hampered. The present work focuses on tuning the physicochemical properties of thymol by modifying its chemical structure through salt formation. In this context, a series of metal (Na, K, Li, Cu, and Zn) and ammonium (tetrabutylammonium and choline) salts of thymol were synthesized and characterized using IR, NMR, CHN elemental analysis, and DSC analyses. The molecular formulae of thymol salts were determined based on CHN analysis and thymol quantification studies from UV‐Vis spectrometric analysis. In most cases, the thymol phenolate was prepared as a 1 : 1 molar ratio with metal/ammonium ion. Only the Cu salt of thymol was isolated at a ratio of two phenolate units per copper ion. Most of the synthesized thymol salts were found to have increased thermal stability relative to thymol. The physicochemical properties such as solubility, thermal stability, and evaporation rate of thymol salts were thoroughly studied in comparison with thymol. The in vitro release studies of Cu from the copper salt of thymol is pH‐dependent: rapid release of copper was observed in the lower pH release medium (100 % release at pH 1 for 12 days) and the rates of release were slower at higher pH values (5 % release at pH 2, and <1 % release at pH 4, 6, 8, and 10) over a period of about three weeks.

show abstract

Section: Introductionmentioning

confidence: 87%

Bioactive Phenolate Salts: Thymol Salts

Reddy

Domb

2023

ChemMedChem

View full text Add to dashboard Cite

show abstract

Rare‐Earth Catalyzed C−H Bond Alumination of Terminal Alkynes

Kanbur

Sadow

2020

Chemistry A European J

View full text Add to dashboard Cite

Organoaluminum reagents' application in catalytic CÀHbond functionalization is limited by competitive side reactions, such as carboalumination andh ydroalumination. Herein, rare-earth tetramethylaluminate complexes are shown to catalyzet he exclusive CÀHb ond metalation of terminal alkynes with the commodity reagents trimethyl-, triethyl-, and triisobutylaluminum.K inetic experiments probing alkyl-group exchange between rare-earth aluminates and trialkylaluminum, CÀHb ond metalation of alkynes,a nd catalytic conversionsr eveal distinct pathways of catalytic aluminationsw ith triethylaluminum versus trimethylaluminum. Most significantly,k inetic data point to reversible formation of au nique [Ln](AlR 4 ) 2 ·AlR 3 adduct, followed by turnover-limiting alkyne metalation. That is, CÀHb ond activation occurs from am ore associated organometallic species, rather than the expected coordinatively unsaturated species. These mechanistic conclusions allude to an ew general strategy for catalytic CÀHb ond alumination thatm ake use of highly electrophilic metal catalysts. representsanonlinear least-squares fit to the equation d[tBuCCAlEt 2 ] = dt = A[AlEt 3 ] = {[AlEt 3 ]+ +B}, where A = k 2 [1 Y ][tBuCCH] and B = (k -1 + +k 2 [tBuC CH]) = k 1 .[ AlEt 3 ] = 0.194-1.419 m;[tBuCCH] = 0.096 m;[1 Y ] = 0.012 M.All manipulations were carried out under inert conditions, either using Schlenk techniques or in gloveboxes under an itrogen at-Caution:T rialkylaluminum and alkynyldialkylaluminum compounds are pyrophoric liquids and must be handled under inert atmospheres. The terminal alkyne and trialkylaluminum reactants were added via syringe to as olution of the catalyst (3 mol %) in [D 6 ]benzene at room temperature, and the reaction mixture was placed in aT eflon-sealed JY oung-style NMR tube. The NMR tube 1 HNMR ([D 6 ]benzene): d = 7.40 (m, 2H, m-C 6 H 5 ), 6.91 (vt, 3 J HH = 7.5, 1H, p-C 6 H 5 ), 6.81 (vt, 3 J HH = 7.5, 2H, o-C 6 H 5 ), 1.50 (t, 3 J HH = 8.1 Hz, 6H,A lCH 2 CH 3 ), 0.64 (q, 3 J HH = 8.1 Hz, 4H,A lCH 2 CH 3 ). 13 C{ 1 H} NMR

show abstract

Recent Advances in Acid–Base and Solvation Properties of Metal Phenolates

Cited by 2 publications

References 169 publications

Bioactive Phenolate Salts: Thymol Salts

Bioactive Phenolate Salts: Thymol Salts

Rare‐Earth Catalyzed C−H Bond Alumination of Terminal Alkynes

Contact Info

Product

Resources

About