Novel compounds of the formula ##STR1## wherein R represents lower alkyl or lower alkoxy, A represents --CH.sub.2 --, --CO-- or ##STR2## n represents an integer of 1 to 8, X represents hydrogen or hydroxyl which may be protected and Y represents hydroxyl which may be protected, and their esters show an excellent action on the lysosomal membranes of cells, and exhibit excellent pharmacological activities such as physiologic host defense control activity, especially immuno-potentiating activity.