Paclitaxel EP Impurity I

Uses

10-O-[(2R,3S)-3-(Benzoylamino)-2-hydroxy-3-phenylpropanoyl]-10-O-deacetylpaclitaxel is an impurity in the synthesis of Paclitaxel (P132500), an antineoplastic. Used in the study of structure and function of microtubles into tubulin. Paclitaxel is now used to treat patients with lung, ovarian, breast cancer, head and neck cancer, and advanced forms of Kaposi's sarcoma.

Synthesis

A method for the preparation of paclitaxel EP impurity I, comprising the steps of:

(1) 10-Dab (5 g, 9.2 mmol) was dissolved in DMF (20 ml), 2-methylimidazole (2.5 g, 30.5 mmol) was added, stirred in a low-temperature bath (10 ), protected by nitrogen, and triethylchlorosilane (1.5 ml, 9 mmol) was added dropwise, and the reaction was carried out for 0.5 h. After 0.5 h, the reaction liquid was extracted by adding water and methylene chloride, and the organic phase was concentrated to obtain 14.8g of intermediate, the yield was 79.2%;

(2) Intermediate 1 (4 g, 6.1 mmol) was dissolved in toluene (40 ml), paclitaxel side chain acid (6.4 g, 24 mmol), 4-dimethylaminopyridine (0.8 g, 6.5 mmol) and N,N’-dicyclohexylcarbamoyl imide (8.1 g, 39.3 mmol), and the reaction was stirred in a low-temperature bath (15 ) for 3h. After that, the reaction solution was extracted and filtered, and the filtrate was concentrated to give 26.0 g of intermediate in 84.3% yield;

(3) Intermediate 2 (6g, 5.1mmol) was dissolved in tetrahydrofuran (60ml) and methanol (60ml), stirred in a cold water bath (10 ), hydrochloric acid (1 mol/L, 30ml) was added dropwise, and after 10h reaction, saturated sodium bicarbonate solution (60ml) was added dropwise, and warmed up to 25 and reacted for 5h, and the reaction solution was extracted by adding water and methylene chloride, and the organic phase was concentrated. The organic phase was concentrated and purified by column chromatography, eluted with mobile phase (dichloromethane:methanol=100:1, V/V) to obtain paclitaxel EP impurity I 4.6g in 83.3% yield.