The subject invention relates to compounds having the structure: ##STR1## wherein: (a) R is unsubstituted C.sub.1 -C.sub.3 alkanyl or alkenyl;(b) R' is selected from unsubstituted C.sub.1 -C.sub.3 alkanyl or alkenyl; unsubstituted C.sub.1 -C.sub.3 alkylthio or alkoxy; hydroxy; thiol; and halo; and(c) R" is selected from hydrogen; unsubstituted C.sub.1 -C.sub.3 alkanyl or alkenyl; methyl monosubstituted with hydroxy, thiol or amino; unsubstituted C.sub.1 -C.sub.3 alkylthio or alkoxy; amino; unsubstituted amide; unsubstituted or C.sub.1 -C.sub.3 substituted amido; halo; unsubstituted sulfoxide; unsubstituted sulfonyl; and cyano;pharmaceutical compositions containing such compounds, and the use of such compounds for preventing or treating respiratory, ocular, and/or gastrointestinal disorders.