1. Field of the Invention
This invention relates to a process for producing oxiracetam(4-hydroxy-2-oxo-1-pyrrolidineacetamide) known as a pharmaceutical (an agent for improving brain metabolism).
2. Related Art Statement
As the process for producing oxiracetam aimed in the present invention, various processes have so far been known, such as (1) a process of obtaining it through reactions of five steps, using ethyl iminodiacetate and ethoxycarbonylacetyl chloride as raw materials (USP No. 4118396/78), (2) a process of obtaining it by using .gamma.-amino-.beta.-hydroxybutyric acid as raw material and adding thereto hexamethyldisilazane or the like, followed by reactions of three steps (Italian Pat. No. 20227A/1977), (3) a process of reacting a glycinamide derivative having a shielding group with a 3,4-epoxybutyric acid ester, followed by shield-removal and cyclization (Italian Pat. No. 19802A/84), and (4) a process of using diketene as starting raw material, followed by reactions of a number of steps, that is, reduction, shielding of hydroxyl group, cyclization, shield-removal, amidation (Italian Pat. No. 20358A/84).
However, any of conventional processes have such drawbacks that raw materials used are expensive and that reactions of many steps are required.