ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A practical and step-economic route to Favipiravir

Feng-Liang Liu, Cui-Qin Li, Hao-Yue Xiang, and Si Feng

Central South University, Changsha, China

E-mail: lflcsu@csu.edu.cn

Abstract: A practical and step-economic route to Favipiravir, an antiviral drug, was developed. Favipiravir was synthesized in only six steps from 3-aminopyrazine-2-carboxylic acid with an overall yield of about 22.3%. Key intermediates 3 and 6 were obtained in excellent purity via recrystallization from optimized solvents, which was beneficial to large-scale production. In the key synthetic reaction, 3,6-dichloropyrazine-2-carbonitrile (6) was reacted sequentially, in one pot, with KF and 30% H₂O₂ to give (after crystallization from 95% EtOH) favipiravir as colorless crystals, with a 60% yield for this final step of the synthesis.

Keywords: Favipiravir; Synthesize; RNA polymerase inhibitor; 3-Aminopyrazine-2-carboxylic acid

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-017-0208-6

Chemical Papers 71 (11) 2153–2158 (2017)