Compounds are disclosed having the structure of Formula I: ##STR00001## where R.sup.1, R.sup.3, and R.sup.4 are independently hydrogen or C.sub.1 to C.sub.4 alkyl, and R.sup.2 is: ##STR00002## where R.sup.5 is selected from the group consisting of hydrogen and C.sub.1 to C.sub.4 alkyl, or ##STR00003## where R.sup.6, R.sup.7 and R.sup.8 are independently hydrogen or C.sub.1 to C.sub.4 alkyl; or the esters or pharmacologically acceptable salts thereof. Such compounds may be utilized for the prophylaxis or treatment of various diseases, particularly inflammatory conditions of the GI tract.Methods of treating inflammatory conditions of the GI tract such as inflammatory bowel disease using compounds having the following formula are also disclosed: ##STR00004## where R.sup.9, R.sup.10 and R.sup.11 are independently selected from the group consisting of hydrogen and C.sub.1 to C.sub.4 alkyl, and R.sup.12 is selected from the group consisting of hydrogen and --C(O)R.sup.13, where R.sup.13 is a C.sub.1 to C.sub.6 alkyl or an aryl group.