Synthesis of favipiravir / 国际药学研究杂志

ABSTRACT

Objective To design and investigate an effective synthetic route of the antivirus compound favipiravir(T-705) with a stable and high yield. Methods The commercial available diethyl aminomalonate hydrochloride was selected as the starting material. The product of aminolysis was cyclized with glyoxal to yield 3-hydroxy-2-pyraziamide, which was subjected to nitration with KNO3, chlorination and dehydration with POCl3 and fluorination with KF to afford 3, 6-difluoropyrazin-2-carbonnitrile. The difluorate product was further hydrolyzed and oxidized to give favipiravir. Results The target compound was efficiently prepared by the above synthetic route. Conclusion The reaction conditions are mild except the fluoro-substitution, in which all reagents should be dried completely. The synthetic procedure is simple, high-yield and suitable for scale preparation.