New synthetic procedure for synthesis of dimethyl 1,4-diaminocyclohexane-1,4-dicarboxylate

The third step of the synthesis deriving dimethyl-1,4-diamino cyclohexane-1,4- dicarboxylate (III) proved to be a difficult task due to its old synthetic route with a few major problems including use of very expensive reagent, mainly hydrogen chloride and ammonia gases. The main purpose of this research was to either optimize/improve the esterification reaction in the original synthetic procedure or in this instance to develop an alternative which improves the yield and reaction time.The result of this research is that dimethyl-1,4-diamino cyclohexane-1,4- dicarboxylate (III) was prepared from 1,4-diamino-1,4-cyclohexane dicarboxylic acid (II) by Fischer etherification using sulfuric acid instead of hydrogen chloride. To remove the sulfate anion from compound III the anion exchange resin DOWEX Monosphere 550A was used. The resulting white suspension was dried using the rotary evaporator to obtain white solid (compound III) with a 42% yield. The product was characterized by TLC, melting point, FT-IR and H-NMR.