Isolation and purification of paclitaxel and cephalomannine

A novel process for extraction, isolation and separation of taxanes, particularly paclitaxel, from natural sources such as bark, needles and twigs from Taxus species, tissue cultures, and fungi is described, wherein the taxanes are separated from the crude extracts by partitioning between polar and nonpolar solvents, precipitation in nonpolar solutions, reacting the mixture by halogenation of unsaturated taxane derivatives, followed by chromatographically separating and crystallizing taxanes from a mixture of polar and nonpolar solvents; more particularly, the process of halogenation of unsaturated side chain taxane derivatives, particularly cephalomannine in presence of paclitaxel, is described, wherein bromine is preferably added to the double bond of unsaturated taxanes leaving paclitaxel unchanged, with paclitaxel being easily separated from the mixture including the less polar halogenated taxane derivatives.