The present invention provides a compound represented by the formula (I) or a salt thereof: ##STR00001## wherein R.sup.1 represents a hydrogen atom, a C.sub.1-10 alkyl group optionally having a substituent, or a protecting group of N; R.sup.2 represents a C.sub.1-10 alkyl group optionally having a substituent or a C.sub.2-10 alkenyl group optionally having a substituent; R.sup.3 and R.sup.4 independently represent a hydrogen atom or a protecting group of hydroxyl group; X represents --N(R.sup.5)R.sup.6 or a residue of amino acid or of an amino group of a peptide wherein R.sup.5 and R.sup.6 independently represent a hydrogen atom, a C.sub.1-10 alkyl group optionally having a substituent, or a C.sub.3-12 cycloalkyl group optionally having a substituent; and Y represents a hydrogen atom, --CH.sub.2NH.sub.2, --CONH.sub.2, or --COOH. The compound of the present invention is useful as a specific inhibitor of sugar chain related enzymes such as glycosyltransferase and glycosidase, and is useful as, for example, a medicine for treating or preventing diseases associated with sugar chain related enzymes.