The present invention is to provide manufacturing intermediates which can be led to useful .alpha.-ketoamide compounds having protease-inhibiting activity extremely economically and stereoselectively, and to provide epoxycarboxamide compounds, azide compounds and amino alcohol compounds represented by the following formulae: wherein R.sup.1 and R.sup.2 each represents alkyl group, alkenyl group, aromatic hydrocarbon group or heterocyclic group; R.sup.3 represents alkyl group, alkenyl group, aromatic hydrocarbon group, heterocyclic group, R.sup.6--O-- or R.sup.7--N(R.sup.8)--; where R.sup.6 represents alkyl group, alkenyl group, aromatic hydrocarbon group or heterocyclic group; R.sup.7 and R.sup.8 each represents hydrogen atom, alkyl group, alkenyl group, aromatic hydrocarbon group or heterocyclic group, and, R.sup.4 and R.sup.5 represent the same groups as R.sup.7 and R.sup.8, respectively, and R.sup.4 and R.sup.5 optionally form a ring together; and X represents --O-- or --N(R.sup.9)--, where R.sup.9 represents hydrogen atom or alkyl group, and X optionally forms a ring together with R.sup.4 or R.sup.5, and processes for preparing .alpha.-keto amide compound using the same.