One-pot Synthesis And Characterization Of Nitrogenous Compounds Under Ultrasound Irradiation

Multi-component reactions are an important class of organic synthesis reaction, bywhich three or more reactants can form a compound containing the main structural fragmentof all components with one-pot method. Because of its high atom economy, convergence,excellent yield and the important applications in design and synthesis of new drug,combinatorial chemistry and synthesis of natural products, the study of one-potmulti-component reactions are getting more and more attention to the synthetic chemists.In recent years, the application of ultrasound irradiation in organic synthesis developedrapidly. Compared with traditional methods, many organic reactions can be carried out undermild conditions, simple operation, in short reaction time with high yield under ultrasoundirradiation. It is a more versatile and facile in many types of chemical reactions, especially thereactions difficult or impossible to occur under normal conditions. In this paper, the principleof sonochemistry and some applications in organic synthesis were introduced, and theapplications of ultrasound in one-pot multi-component reactions were reviewed. Four kindsof nitrogenous compounds were syntheisized by one-pot synthesis under ultrasoundirradiation and characterized by their spectral data.Ultrasound-promoted synthesis of β-acetamido ketones catalyzed by cobalt sulfateheptahydrate via one-pot multi-component reaction coupling of aromatic aldehyde,acetophenone and acetyl chloride in acetonitrile was carried out in excellent yields at25~28oC. The effect of the amount of the catalyst on the reaction was investigated, and the resultsunder different conditions were compared. It indicated that the results of the reaction underultrasound irradiation were obviously superior to those under reflux condition.One-pot synthesis of O-arylsulfonyl arylaldoximes was carried out in56%~94%yieldswithin15~60min via the condensation of arylaldoxime with aromatic sulfonyl chloride in thepresence of sodium hydroxide at room temperature in dichloromethane under ultrasoundirradiation. The effect factors on the reaction such as the molar ratio of the reactant, the kindsof catalyst, and the frequency of ultrasound irradiation were studied. The advantages of this methodology are convenient operation, mild conditions, short reaction times, and high yields.It provides a simple and efficient method for the similar compounds.A convenient and efficient one-pot synthesis of2-thioxo-dihydropyrimidine derivativesbearing piperidinylamide moiety was carried out in81%~91%yields within1~2h via thecondensation of1-(piperidin-1-yl)butane-1,3-dione with aromatic aldehyde and thiourea inethanol catalyzed by p-toluenesulfonic acid at room temperature under ultrasound irradiation.Comparing with the results under traditional refluxing conditions, the advantages of thismethodology are shorter reaction times and higher yields.A series of2,3-disubstituted-2,3-dihydroquinazolin-4(1H)-one derivatives weresynthesized in80%~92%yields within1~2h by one-pot three-component condensation ofisatoic anhydride, aromatic aldehyde and amine using dodecylbenzenesulfonic acid ascatalyst in aqueous medium at40~42oC under ultrasound irradiation. Simple experimentaland work-up procedures, mild reaction conditions, avoid the use of organic solvents, andfriendly to environment are the salient features of this protocol.