Aims:
Aims:The application of 3,5-Bis(trifluoromethyl) phenyl ammonium triflate(BFPAT) as a convenient and novel organocatalyst for the synthesis of quinoxalines.
Background:
Recently, ammonium triflate-based organocatalysts have been rapidly evolved, and most of them have been synthesized and utilized in several organic transformations.
Objective:
1) introducing a new organocatalyst 2) introducing a practical method for the synthesis of quinoxalines 3) to overcome some problem in this method 4) using water as a green solvent.
Method:
A water solution (3 ml) of 1,2-dicarbonyl compounds (1 mmol) and aryl 1,2-diamines (1 mmol) was mixed with BFPAT (10 mol%), and the resulting mixture was stirred at rt for an appropriate time. Upon completion of the reaction, (monitored by TLC), the resultant was cooled with the ice bath, filtered and washed with ethanol and purified by recrystallization from hot ethanol to afford pure products.
Result:
A wide variety of quinoxaline derivatives was achieved by the reaction of various substituted o-phenylenediamines and 1,2-diketones in water.
Conclusion:
A simple and new ammonium triflate-based organocatalyst was shown to effectively promote the highly efficient synthesis of quinoxalines in water as a green reaction medium. Compared to prior studies, the substrate scope of the starting material was largely extended. In particular, the synthesis avoids the toxic metals in the products, which provides a green and practical method for organic synthesis.
Other:
In particular, the synthesis avoids the toxic metals in the products, which provides a green and practical method for organic synthesis.
New methods and reagents in organic synthesis, 29, A practical method for the preparation of optically acive N-protected .ALPHA.-amino aldehydes and peptide aldehydes.
