Synthesis and biological evaluation of novel taxol derivatives having
a phosphonoxyphenylpropionate ester group at the 2'-position or at the
7-position of taxol are described. These were found to have much impr
oved water solubility and both were found to generate taxol upon expos
ure to alkaline phosphatase. A particular derivative, 7-phosphonoxyphe
nylpropionate of taxol 3b exhibited antitumor activity comparable to t
hat of taxol against the ip/ip M109 murine tumor model.