Compounds of formula (I): ##STR1## �wherein: X represents an unsubstituted or substituted indolyl, indolinyl, azaindolyl, azaindolinyl, imidazopyridyl or imidazopyrimidinyl group; Y represents an oxygen or sulfur atom; Z represents a 2,4-dioxo-thiazolidin-5-ylidenylmethyl, 2,4-dioxothiazolidin-5-ylmethyl, 2,4-dioxooxazolidin-5-ylmethyl, 3,5-dioxo-oxadiazolidin-2-ylmethyl or N-hydroxyureidomethyl group; R represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a hydroxy group, a nitro group, an aralkyl group or a unsubstituted or substituted amino group; and m is an integer of from 1 to 5! have hypoglycemic and anti-diabetic activities.