| 摘要 |
<p>A process for preparing (S)-tetrahydro-a-(1-methylethyl)-2-oxo-1(2H)-pyrimidineacetic acid, an intermediate that is useful in the synthesis of HIV protease inhibitors such as, for example, those described in US-5 914 332, is described.The process under consideration comprises the following steps:- L-valine is reacted with acrylonitrile;- the N-(2-cyanoethyl)-L-valine thus obtained is isolated and then reacted with an alkyl chloroformate;- the N-(2-cyanoethyl)-N-(alkoxycarbonyl)-L-valine thus obtained is hydro-genated in the presence of a hydrogenation catalyst, preferably rhodium;- the N-(3-aminopropyl)-N-(methoxycarbonyl)-L-valine thus obtained is cyclized to give the desired compound.</p> |
