Dipeptide derivative and prophylactic and therapeutic agent for bone diseases containing the same

A dipeptide derivative represented by the formula (I):

• R.sup.1 NH--CH(R.sup.2)--CO--NH--CH(R.sup.3)--R.sup.4 (I)
• wherein R represents an aliphatic acyl group, a halogen-substituted aliphatic acyl group, or benzyloxycarbonyl group;
• R.sup.2 represents a lower alkyl group or an aralkyl group;
• R.sup.3 represents a lower alkyl group, or an aralkyl group, or methylthioethyl group;
• and
• R.sup.4 represents an aliphatic acyl group substituted with a lower alkoxycarbonyl group, or R.sub.4 represents a di-lower alkoxymethyl group, a diacyloxymethyl group, a 1-hydroxy-2-lower alkoxycarbonylethyl group, a halogen-substituted 1-hydroxy-2-lower alkoxycarbonylethyl group, hydroxyiminomethyl group, ureidoiminomethyl group, benzimidazol-2-yl group, or a group:
• ##STR49## wherein A and B, which may be the same or different, each represents O, S, NH;
• and n represents 2 or 3.

A method of inhibiting loss of calcium from the bones [preventing or treating a bone resorption disease selected from malignant hypercalcemia, bone Paget's disease and osteoporosis] comprising administering to a patient in need of same an effective amount of a dipeptide represented by the formula (I):

• R.sup.1 NH--CH(R.sup.2)--CO--NH--CH(R.sup.3)--R.sup.4 (I)
• wherein R.sup.1 represents an aliphatic acyl group, a halogen-substituted aliphatic acyl group. or benzyloxycarbonyl group;
• R.sup.2 represents a lower alkyl group or an aralkyl group;
• R.sup.3 represents a lower alkyl group, or an aralkyl group, or methylthioethyl group;
• and
• R.sup.4 represents an aliphatic acyl group substituted with a lower alkoxycarbonyl group, or R.sub.4 represents a dilower alkoxymethyl group, a 1-hydroxy-2-lower alkoxycarbonylethyl group, a halogen-substituted 1-hydroxy-2-lower alkoxycarbonylethyl group, hydroxyiminomethyl group, ureidoiminomethyl group, benzimidazol-2-yl group, or a group:
• ##STR50## wherein A and B, which may be the same or different, each represents O, S, NH;
• and n represents 2 or 3.