32981-91-2

Upstream product

• 32981-86-5 10-deacetylbaccatin III 
• 32981-90-1 7-O-acetylbaccatine III 
• 108-24-7 acetic anhydride 
• 92950-42-0 13-dehydro-10-deacetylbaccatin III 

Downstream Products

• 1215640-95-1 [13-⁽³⁾H]-7-O-acetylbaccatin III 

Relevant academic research and scientific papers

Point mutations (Q19P and N23K) increase the operational solubility of a 2α-o-benzoyltransferase that conveys various acyl groups from CoA to a taxane acceptor

Two site-directed mutations within the wild-type 2-o-benzoyltransferase (tbf) cDNA, from Taxus cuspidata plants, yielded an encoded protein containing replacement amino acids at Q19P and N23K that map to a solvent-exposed loop region. The likely significant changes in the biophysical, properties invoked by these mutations caused the overexpressed, modified TBT (mTBT) to partition into the soluble enzyme fraction about 5-fold greater than the wild-type enzyme. Sufficient protein could now be acquired to examine the scope of the substrate specificity of mTBT by incubation with 7,13-O,O-diacetyl-2-Odebenzoylbaccatin III that was mixed individually with various substituted benzoyls, alkanoyls, and (E)-butenoyl CoA donors. The mTBT catalyzed the conversion of each 7,13-O,O-diacetyl-2-O-debenzoylbaccatin III to several 7,13-O,O-diacetyl-2O- acyl-2-O-debenzoylbaeeatin III analogues. The relative catalytic efficiency of mTBT with the 7,13-O,O-diacetyl-2-Odebenzoyl surrogate substrate and heterole carbonyl CoA substrates was slightly greater than with the natural aroyl substrate benzoyl CoA, while substituted benzoyl CoA thioesters were less productive. Short-chain hydrocarbon carbonyl and cyclohexanoyl CoA thioesters were also productive, where C4 substrates were transferred by mTBT with ～10- to 17-fold greater catalytic efficiency compared to the transfer of benzoyl. The described broad specificity of mTBT suggests that a plethora of 2-O-acyl variants of the antimitotic paclitaxel can be assembled through biocatalytic sequences.

Diastereoselective 14beta-hydroxylation of baccatin III derivatives.

14beta-Hydroxybaccatin III, a compound with limited availability by natural sources, is the starting material for the synthesis of the second-generation anticancer taxoid ortataxel. The 7-tert-butoxycarbonyl (1a) and 7-triethylsilyl (1b) derivatives of 14beta-hydroxybaccatin III 1,14-carbonate were synthesized from 10-deacetylbaccatin III (3). The crucial steps were (a) the C(14)beta hydroxylation of the corresponding 13-oxobaccatin III derivatives by oxaziridine-mediated electrophilic oxidation and (b) the reduction of the C(13) carbonyl group with sodium or alkylammonium borohydrides. This protocol provides a practical way for the semisynthesis of ortataxel from 10-deacetylbaccatin III, a compound readily available from various yews.