Syntheses And Crystal Studies Of Novel C-3 '-N-Sulfonyl And 7-O-Acyl Modified Paclitaxel Analogues

Three C-3'-N-sulfonyl and C-7-O-acyl paclitaxel analogues were synthesized from 10-deacetyl baccatin III (10-DAB) and their structures were confirmed by H-1 NMR, C-13 NMR and HR-MS. Among them, the crystal structure of compound 9b was determined by single-crystal X-ray diffraction. Compound 9b crystallizes in monoclinic system, space group P2(1), with a = 12.395(4), b = 15.215(5), c = 14.905(5) angstrom, beta = 105.559(4)degrees and Z = 2. In the structure, the introduction of the hydrophobic 3-fluorobenzoyl group at C(7) has little effect on the conformation of tetracyclic system. However, the conformation of the side-chain at C(13) in 9b is quite different from that of paclitaxel and docetaxel.