If you have any other questions or need other size, please get a quote.
Sajith, Ayyiliath M., and A. Muralidharan. Tetrahedron Letters 53.39 (2012): 5206-5210.
Tetrabutyl ammonium acetate (TBAA) has been employed as a key activator in the copper-free Sonogashira coupling reaction of 2-halo-3-alkyl imidazo[4,5-b]pyridines with terminal acetylenes. This reaction was efficiently catalyzed by PdCl2(PCy3)2 under microwave-enhanced conditions, enabling rapid cross-coupling without the need for amines or copper co-catalysts.
The reaction setup involved dissolving the 2-halo imidazo[4,5-b]pyridine derivative in NMP, followed by the addition of terminal acetylene and TBAA in equimolar amounts. The solution was purged with nitrogen before introducing PdCl2(PCy3)2, and after a second nitrogen purge, the mixture was heated at 110°C for iodide and bromide substrates or 150°C for chloride derivatives. Reaction progress was monitored by TLC and LCMS. Upon completion, the mixture was extracted using ethyl acetate, washed with brine, dried over anhydrous sodium sulfate, and purified via column chromatography.
The use of TBAA in this protocol facilitated efficient coupling, likely by enhancing the solubility of reactants and stabilizing the catalytic system. This study demonstrates TBAA's crucial role in Sonogashira coupling, particularly in copper-free methodologies, broadening its application in modern organic synthesis.
Miao, J., Sun, H., Yu, Y., Song, X., & Zhang, L. (2014). RSC Advances, 4(69), 36721-36724.
Tetrabutyl ammonium acetate (TBAA) has been demonstrated as an effective solvent for cellulose dissolution when combined with dimethyl sulfoxide (DMSO) and 18-crown-6 (18C6). This novel solvent system enables rapid dissolution of cellulose at mild temperatures without requiring any pretreatment, making it highly advantageous for cellulose processing.
Cellulose (8%) with a degree of polymerization (DP) of 830 was completely dissolved in TBAA/DMSO/18C6 within 5 minutes at 40°C under stirring. The dissolution process, monitored by confocal laser scanning microscopy, revealed an initial rapid dissolution phase followed by a slower stage due to increased viscosity and the presence of more crystalline cellulose structures. Microcrystalline cellulose (DP 200) exhibited even higher solubility, reaching up to 20%. Notably, cotton linter could also be dissolved in this solvent system, further highlighting its versatility.
Unlike conventional solvents that require high temperatures or prolonged treatment, TBAA/DMSO/18C6 offers a highly efficient and mild approach for cellulose solubilization. This system provides a promising platform for cellulose-based material development, chemical modification, and sustainable processing in industrial and scientific applications.
Bellina, Fabio, Marco Lessi, and Chiara Manzini. European Journal of Organic Chemistry 2013.25 (2013): 5621-5630.
Tetrabutylammonium acetate (Bu₄NOAc) has been identified as a crucial promoter in palladium-catalyzed direct arylation of azoles, enabling regioselective functionalization under mild conditions. This ligand-free reaction facilitates the selective 5-position arylation of 1-methylpyrazole, oxazole, and thiazole with aryl bromides at only 70°C. In contrast, 1-methylimidazole required a higher temperature of 110°C for efficient coupling.
Bu₄NOAc plays a vital role in activating the palladium catalyst, eliminating the need for additional ligands or bases. Notably, this methodology was successfully applied to the one-pot sequential 5- and 2-diarylation of oxazole, leading to the synthesis of bioactive natural products, balsoxin and texaline. The reaction proceeded efficiently using 2.0 equivalents of Bu₄NOAc and 5 mol% Pd(OAc)₂ in DMA, followed by a second arylation step with CuI as an additive.
This approach highlights Bu₄NOAc's ability to facilitate direct C-H activation, enhancing reaction efficiency while minimizing reagent requirements. Its effectiveness in regioselective arylation makes it a valuable tool for synthesizing complex heterocyclic compounds, particularly in pharmaceutical and materials chemistry applications.
