An Efficient Route To α-acyloxy Carboxamides Based On Isonitriles And Aldehydes

The-acyloxy carboxamide compounds are present in the structures of manynatural products, such as the pharmacologically active depsipeptides. Thesebifunctional compounds are important organic intermediates and have wideapplication in organic synthesis.Isonitrile is a class of important reageat to build nitrogen-containing compoundsand the formation of carbon-carbon bond due to the special structure which has avery high reactivity. They are very important synthons in organic synthesis isextremely. Multicomponent reaction has advantages of the atom economy, efficiency,structural diversity, regioselectivity, stereoselectivity chemoselective and high BFI, ithas been widely used in modern organic synthesis. Isocyanide basedmulticomponent reactions are very important class of multi-component reactions.Because of the high reactivity of isonitriles, isocyanide based multicomponentreactions are more versatile and variable than other multicomponent reactions.The focus of green chemistry is to improve atomic efficiency and reduce the useof organic solvents. Using green solvents or solvent-free condition become hot ingreen chemistry. Solvent-free reaction is a bright and useful technique because itincreased the concentration of the reaction and the reaction rate, yield selectivity andspace utilization are all improved.In the first chapter of this thesis, the-acyloxy carboxamide, isonitrile, andisocyanide based multicomponent reactions were introduced firstly, and then theadvantages and applications of solvent-free reaction were introduced.In the second chapter, an efficient approach for the synthesis ofα-acyloxycarboxamides via aldehyde and isocyanide in the presence of a minimum supply of water under solvent-free condition was reported. The effects of the amountof aldehyde, the amount of water and the temperature were discussed. And theoptimal experimental condition was established: the best results were obtained in themolecular ratio1:3:3for isocyanide: aldehydes: H2O, at40℃under solvent-freeconditions.93%yield was got under the optimal experimental conditions. Inaddition, the cross products with a unique type of structure were obtained by usingtwo different aldehydes.Notably, the reaction occurred in air and the amount of water was quantitative.The reaction occured under mild conditions, the yield and efficiency were high, andthe reaction did not need to isolate any intermediate. The products precipitated in thesystem directly and the pure products were obtained by using petroleum etherwashed for two times. The reaction was easy to operate; it did not needrecrystallization or column chromatography and reduced the material loss.All synthesized compounds were characterized by IR、1H NMR、13C NMR andHRMS. The unambiguous molecular structure of3e and6b were determined byX-ray diffraction analysis. And the plausible mechanism was also presented...