Synthesis of N′-alkyl-N,N-dimethylacetamido bicarbonate and its characterization

A series of intermediate N′-alkyl-N,N-dimethyacetamidine was synthesized by both direct and indirect method using a series of alkylamine,N,N-dimethylacetamide(DMAC) et al as starting materials.The series product,N′-alkyl-N,N-dimethylacetamidino bicarbonate,was obtained by reaction of the intermediate with an excess amount of dry ice.Suitable conditions of direct method of synthesizing N′-dodecyl-N,N-dimethylacetamidine were identified as follows:10 mL of chloroform as solvent for every 0.01 mol of dodecylamine;POCl3 as dehydrating and pH regulating agent;mole ratio for the materials used,n(dodecylamine)∶ n(DMAC)∶ n(POCl3)=1∶ 2.5∶ 0.35;reaction temperature,61 ℃ for 24 h.Yield of the product achieves 90.2%.In the process using indirect method,firstly,DMAC reacted with dimethyl sulfate to form N,N-dimethyl acetamide dimethyl sulfate(the imine-complex).Then the imine-complex reacted with sodium methoxide to form N,N-dimethyl acetamide dimethyl acetal,and then further reacted with alkyl amine to form the intermediate N′-alkyl-N,N-dimethyacetamidine.Conditions for the synthesis of N,N-dimethyl acetamide dimethyl acetal were systemically studied and the suitable conditions were identified as follows:n(sodium methoxide)∶ n(DMAC)∶ n(dimethyl sulfate)=1.2∶ 1∶ 1;time for adding imine-complex under control within 2 h at temperature not over 0 ℃;with continue reaction time of 3 h under-5 ℃.The yield of N,N-dimethyl acetamide dimethyl acetal achieves 46.4%.The final product was characterized by IR,MS and 1HNMR.