Some spirooxindole derivatives have been demonstrated earlier to inhibit HIV reverse transcriptase [1]. This ability is manifested at concentrations close to the concentrations of active drugs (EC50 = 50 nM). Previously, we have also shown that such spirooxindoles have significant activity against another retroviral enzyme - integrase [2]. However, it should be mentioned that none of the individual enantiomers were tested for their biological properties, but rather their racemic mixtures. Usually only one of the enantiomers is active, that is why one can expect that the use of pure enantiomers will increase the activity twice, will reduce the dosage and, consequently, diminish the toxicity.Therefore, the hit compound 1 was purposely derivatized to form diastereomers. Leucine was chosen as an asymmetric fragment, which formed a peptide bond with the carboxyl group of 2 (Scheme 1). However, the resulting mixture of diastereomers could not be separated.formulaScheme 1. The synthesis of compounds 2, 3, 4 (i: NaOH 0.2M). Leucine was replaced by its cyclopentyl ester. The resulting mixture of 5 and 6 was chromatographically inseparable, but one of the products could be crystallized (Scheme 2).formulaScheme 2. Synthesis of the compounds 5 and 6. The resulting ester 5 was hydrolyzed, which led to the target product 3 (Scheme 3).formulaScheme 3. Synthesis of the compound 3.