Abstract: The invention relates to novel processes and intermediates for the preparation of 5-amino-4-hydroxyvaleric acid derivatives of the formula ##STR1## in which R.sup.1 represents hydrogen, optionally substituted alkyl, cycloalkyl, cycloalkyl-lower alkyl, aryl, aryl-lower alkyl or the radical of a natural amino acid, R.sup.2 represents hydrogen, optionally substituted alkyl, cycloalkyl, cycloalkyl-lower alkyl, aryl, aryl-lower alkyl, amino, hydroxy, mercapto, sulphinyl, sulphonyl or the radical of a natural amino acid, and R.sup.3 represents optionally substituted hydroxy or amino, by sigmatropic rearrangement of a suitable allyl ester, halolactonisation of the resulting .gamma.,.delta.-unsaturated acid or of a suitable derivative thereof, exchange of halogen for a nitrogen-containing nucleophile, opening of the lactone ring and freeing of the amino group. Compounds of the formula I are starting materials for the preparation of renin-inhibitors which have an anti-hypertensive action.

Abstract: A hydroxy-carboxylate ester is converted to an amino-acid-amide by replacement of the --OH group with --N.sub.3, via, e.g., CH.sub.3 SO.sub.2 Cl and NaN.sub.3 ; reacting with amine to convert the ester to amide; and hydrogenating --N.sub.3 to --NH.sub.2. The present process alleviates the conventional use of blocking-deblocking procedures.