| abstract |
(57) [Summary] (Modified) [Objective] To provide a retroviral protease inhibitor useful as a therapeutic agent for retroviral diseases. [Structure] An asparagine derivative represented by the formula (I), and a retroviral disease therapeutic agent containing the derivative. [Ring A may be a 5- to 7-membered ring such as a pyrrolidine ring, and R 1 and R 2 may both represent a hydrogen atom or may be bonded to each other to form a condensed ring. R 3 is a carboxyl group which may be esterified or amidated, R 4 is a hydrogen atom or an acyl group, X is —CH (OH) —, or —C (= O) -indicates. The compound of formula (II) is a typical example of the above-mentioned asparagine derivative. |