In order to develop new taxol analogues with possible antitumor properties, sinenxan A (SIA), a new biosynthetic taxoid, was chemically modified, mainly by esterification of C14-OH with taxol-like side-chain acids. Twenty-one new taxoids thus formed were tested on three kinds of cell lines. Their activities are far below those of taxol. The SAR of SIA derivatives partly agree with that of taxol and can be roughly discerned.