METHOD FOR PACLITAXEL SYNTHESIS

摘要

A method for producing paclitaxel is accomplished by first esterifying C-7-CBZ baccatin III with a C3'-N-CBZ-C2'-O-protected (2R, 3S)-3-phenylisoserine side chain to form a first intermediate. Next, the carbobenzyloxy groups at C-7 and at the C3' nitrogen site of the first intermediate are respectively replaced with hydrogen and PhCO to produce a second intermediate that is next deprotected at C2' by replacing the protecting group with hydrogen. The C2' protecting group is a benzyl-type protecting group, preferably benzyloxymethyl or benzyl. Excess amounts, such as six equivalents, of the side chain are preferably employed. DMAP and a dialkylcarbodiimide are also preferably used during esterification. Various preferred reaction temperatures, times, and purification steps are disclosed.