The Catalytic Preparation Resreach Of Allenes And Thioamides

Allenes and its derivatives, which has 1,2-allene functional groups and important biological activity, are an intermediate of many organic reactions. Allenes can be applied in Diels-Alder reaction and cycloaddition, meanwhile, they can effectively control the configuration. The disulfide moiety is found in many biologically important structures and is considered as a useful synthon for many organic synthetic transformations. It has wide applications in chemical substitution or addition reactions. In view of presence of sulfur in numerous chemically and biologically active compounds, there is much interest to develop ways for the generation of carbon-sulfur bonds. Thioamides are structural motifs widely used as key intermediates and versatile building blocks for the construction of heterocycles and other compounds containing both nitrogen and sulfur in their backbones. Replacement of the oxygen atom by a sulfur atom in the carboxamide moieties was used to modify the stability and catalytic activities of target molecules. In this article, we proposed to cesium hydroxide-catalyzed to obtain allenes, molecular iodine-catalyzed to prepare thioamides, in these conditions, we obtain a series of significant compounds.Specific work is as follows:(1) The reaction of 1-methoxy-4-(prop-2-yn-1-yloxy)benzene was used as model reactants to explore the influence of amount of catalyst, solvent, temperature and reaction time. Optimal conditions are obtained as follows:CsOH (0.2 equiv.), CH3CN,40?,4 h. We examined the scope and versatility of this reaction, and got the yield 64-86%.(2) The reaction of N-(4-chlorophenyl)-N-(prop-2-yn-l-yl)acetamide was used as model reactants to explore the influence of amount of catalyst, solvent, temperature and reaction time. Optimal conditions are obtained as follows:CsOH (0.2 equiv.), CH3CN,60?,4 h. We examined the scope and versatility of this reaction, and got the yield 61-83%.(3) The reaction of 1,2-dibenzyldisulfane and 1-methylpiperazine was used as model reactants to explore the influence of amount of catalyst, solvent, temperature and reaction time. Optimal conditions are obtained as follows:I2 (0.5 equiv.), DMSO,100?,8h. We examined the scope and versatility of amides with 1,2-dibenzyldisulfane, and got the yield 17-95%.(4) The reaction of difurfuryl disulfide and 1-methylpiperazine was used as model reactants to explore the influence of amount of catalyst, solvent, temperature and reaction time. Optimal conditions are obtained as follows:I2 (0.5 equiv.), DMSO,100?,8 h. We examined the scope and versatility of amides with difurfuryl disulfide, and got the yield 37-78%.This paper reported cesium hydroxide-catalyzed to prepare allenes, the advantage of this system is cheap raw materials, simple experimental operation, strong compatibility, atom economy and friendly to the environment, etc. For the reaction of molecular iodine-catalyzed to obtain thioamides, it has the following advantages:the experimental operation is simple, the reaction of compatibility is nice, subsequent experiment processing is simple and the yield of the product is good, etc.All unknown compounds were characterized by 1H NMR and 13C NMR and MS. All compounds of thioamides were characterized and confirmed by 1H NMR and 13C NMR, MS and Hrmasss. The configurations of the desired products were confirmed by crystal analysis.