Highly effective reduction of 2 '',3 ''-dibromocephalomannine under ultrasound irradiation

Dibromocephalomannine(DIBROCs)is the intermediate product in the purification of taxol. In this paper, we successfully realized the efficient conversion of DIBROCs to cephalomannine under ultrasound irradiation for the first time. Ultrasound irradiation, a favorable acceleration of reaction rates, could solve the problems of incomplete conversion of DIBROCs to cephalomannine and the by-products due to long reaction time under the traditional stirring condition. The results showed that under ultrasound irradiation zinc powder was more effective than other metal powder and the proper reaction temperature was 20 ℃. Under this condition the conversion was more than 98% in 40 min.