A method for preparing cyclic amino acid

The present invention relates to a method for the efficient production of amino-acid A: A 4- (acetylamino) benzoic acid as a starting material, the reduction by hydrogenation, the hydrogenation catalyst was removed by filtration, the reaction solution was distilled to curing, heating and baking transformation. Dissolved in water, the reaction solution was adjusted to neutral acid, p-toluenesulfonic acid into a salt, filtered, and weakly basic anion-exchange resin exchange resin, the eluent was distilled to a large amount of solid precipitated crystals were added appropriate amount of ethanol, cooled and filtered, washed, and dried to give tranexamic acid. This method produced tranexamic acid, cis isomer content is less than 0.05%. Quality in full compliance with domestic and international pharmacopoeia standards, product quality and higher than the existing domestic reporting. Production route of the present invention has fewer steps, simple, high yield, energy saving and environmental advantages.