The present invention is to provide manufacturing intermediates which can be led to useful α-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 R1 and R2 each represents alkyl group, alkenyl group, aromatic hydrocarbon group or heterocyclic group; R3 represents alkyl group, alkenyl group, aromatic hydrocarbon group, heterocyclic group, R6—O— or R7—N(R8)—; where R6 represents alkyl group, alkenyl group, aromatic hydrocarbon group or heterocyclic group; R7 and R8 each represents hydrogen atom, alkyl group, alkenyl group, aromatic hydrocarbon group or heterocyclic group, and, R4 and R5 represent the same groups as R7 and R8, respectively, and R4 and R5 optionally form a ring together; and X represents —O— or —N(R9)—, where R9 represents hydrogen atom or alkyl group, and X optionally forms a ring together with R4 or R5, and processes for preparing α-keto amide compound using the same.