Study On The Synthesis Of Gadodiamine And Asparagine

Gadolinium diamine is an extracellular fluid paramagnetic contrast agent for magnetic resonance imaging,which indirectly changes the tissue signal strength through internal and external relaxation effects and magnetic susceptibility effects.It has been widely used in clinical diagnosis and treatment because of its multi-parameter "high-resolution" azimuthal tomography and safe harmless.Asparagine is an important amino acid derivatives,which has been mainly used in pharmaceutical intermediates,biochemical reagents and clinical medicine.In addition,it has a wide range of application in rubber additives,sweeteners and fodder.In the presence of pyridine and acetic anhydride,diethyltriaminepentaacetic acid(DTPA)as raw material convert into the diethyltriaminepentaacetic acid dianhydride.The diethylenetriaminepentaacetic acid anhydride and methylamine aqueous solution react into 5,8-bis-carboxymethyl-11-[2-(methylamino)-2-oxoethyl]-3-oxo-2,5,8,11-tetraazatridecyl-13-carboxylic acid,it has to do with gadolinium oxide complexing gadolinium diamine.The total yield of three steps was achieved70.9 %.By dropping thionyl chloride in low temperature,aspartic acid as raw material react into aspartic acid methyl ester hydrochloride via esterification,then in the presence of catalyst triethylamine and ammonia,aspartic acid methyl ester hydrochloride via aminolysis reaction generates into asparagine.The total yield of the two steps was reached 64.9 %.The final product was identified as the target product by1 H NMR.Through the optimization of the two process lines,the purity and yield of the final product has been greatly improved.The two processes have the advantages of low cost,high yield,little environmental pollution and easy operation,and it is suitable for industrial production.