FR900098 represents an improved derivative of the new antimalarial drug fosmidomycin and acts through inhibition of the 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase, an essential enzyme of the mevalonate independent pathway of isoprenoid biosynthesis. Prodrugs with increased activity after oral administration were obtained by chemical modification of the phosphonate moiety to yield acyloxyalkyl