Preparative scale isolation and purification of taxanes

A process for the purification of taxanes from an extract of plant material of a taxus genus which comprises the following steps:

• (i) substantially taking up the extract of plant material of a taxus genus in a volume of a first organic solvent to form a solution and whilst agitating the solution gradually adding a second organic solvent, wherein said second solvent is of lower polarity than said first solvent, precipitating a solid;
• (ii) recrystallizing said precipitated solid to form a crystalline product;
• and
• (iii) separating said crystalline product from its mother liquor.

A process for obtaining taxanes from Taxus canadensis which comprises

• (a) drying the vegetal material obtained from the Taxus plant at a temperature of between 20.degree. C. and 70.degree. C. to form dried plant matter;
• (b) contacting the dried plant matter from step (a) with an organic solvent that is, or an equivalent organic solvent whose polarity is equivalent to, a solution of methanol:dichloromethane ranging in concentration from 1:5 to 1:15 so as to extract a crude taxane mixture in the extracting solvent mixture;
• (c) washing the extract of (b) with water;
• (d) filtering the extract over charcoal;
• (e) evaporating the filtered extract of (d) to remove organic solvent leaving a residue;
• (f) dissolving the residue of (e) in toluene, or an equivalent organic solvent, to which petroleum ether, or an equivalent organic solvent, is added under fast uninterrupted stir to form a residue-solution;
• (g) filtering the residue-solution of (f) to accumulate a solid;
• (h) drying the solid of (g);
• and
• (i) dissolving the dried solid of (h) in methanol or an equivalent organic solvent to crystallize 9-dihydro-13-acetylbaccatin III out of said dissolved dried solid and filtering to separate into a solid and a filtrate A.