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.
描述了一种制备(S)-四氢-α-(1-甲基乙基)-2-氧代-1(2H)-
嘧啶乙酸的过程,这是在合成HIV蛋白酶抑制剂中有用的中间体,例如在美国专利5,914,332中描述的那些。考虑的过程包括以下步骤:-
L-缬氨酸与
丙烯腈反应;- 分离得到的N-(2-
氰乙基)-
L-缬氨酸然后与烷基
氯甲酸酯反应;- 在氢化催化剂的存在下,优选是
铑的条件下,氢化得到的N-(2-
氰乙基)-N-(烷氧羰基)-
L-缬氨酸;- 得到的N-(3-
氨丙基)-N-(甲氧羰基)-
L-缬氨酸被环化,形成所需的化合物。