.DELTA..sup.6,7 -taxols antineoplastic use and pharmaceutical compositions containing them

A process of preparing wherein R.sub.1 is selected from the ground consisting of

• --CH.sub.3,
• --C.sub.6 H.sub.5 or phenyl substituted with one, 2 or 3 C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.3 alkoxy, halo, C.sub.1 -C.sub.3 alkylthio, trifluoromethyl, C.sub.2 -C.sub.6 dialkylamino, hydroxy or nitro,
• -2-furyl, 2-thienyl, 1-naphthyl, 2-naphthyl or 3,4-methylenedioxyphenyl;
• R.sub.10 is --H or --C(O)CH.sub.3 ;
• R.sub.11 is phenyl substituted with --(OC.sub.1 -C.sub.2 alkyl).sub.n where n is 1 to 3;
• R.sub.12 is selected from the group consisting of
• --C(O)H,
• --C(O)phenyl substituted with one, 2 or 3 C.sub.1 -C.sub.3 alkylthio, C.sub.2 -C.sub.6 dialkylamino, hydroxy or nitro,
• --SO.sub.2 -4-methylphenyl,
• --C(O)(CH.sub.2).sub.3 COOH,
• --C(O)-4-(SO.sub.3 H)phenyl,
• --C(O)-1-adamantyl,
• --C(O)O-3-tetrahydrofuranyl,
• --C(O)O-4-tetrahydropyranyl,
• --C(O)NHC.sub.1 -C.sub.10 alkyl,
• --C(O)NHPh substituted with one, 2 or 3 C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.3 alkoxy, halo, C.sub.1 -C.sub.3 alkylthio,
• trifluoromethyl, C.sub.2 -C.sub.6 dialkylamino, or nitro,
• --C(O)C(CH.sub.3).sub.2 CH.sub.2 Cl,
• --C(O)- 1-phenyl- 1-cyclopentyl,
• --C(O)- 1-methyl- 1-cyclohexyl,
• --C(S)NHC(CH.sub.3).sub.3,
• --C(O)NHC(CH.sub.3).sub.3 or
• --C(O)NHPh;
• R.sub.14 is selected from the group consisting of --C(O)C.sub.1 -C.sub.6 alkyl, --C(O)OC.sub.1 -C.sub.6 alkyl, --C(O)OCH.sub.2 CX.sub.3 where X is Halo, --C(O)OCH.sub.2 CH.sub.2 Si(R.sub.20).sub.3 (where R.sub.20 is C.sub.1 -C.sub.6 alkyl), or --Si(R.sub.20).sub.3 ;
• which comprises reacting an oxazolidine free acid of Formula 7 ##STR13## wherein R.sub.1, R.sub.11 and R.sub.12 are as defined above;
• with a baccatin compound of Formula 8 ##STR14## wherein R.sub.10 and R.sub.14 are as defined above;
• in the presence of a dehydrating agent.