A PROCESS FOR THE REGENERATION OF 6-FLUORO-4-CHROMANONE

摘要

This invention relates to the regeneration of 6-fluoro-4chromanone. A mixt. of R- and RS-6-fluorospiro[chroman-4,4'-imidazolidine -2',5'- dione(or a mixt. of R-and RS-6-fluoro-4-Ureidochroman-4-carboxylate) is hydrolyzed to give a mixt. of R- and RS-4-amino-6-fluorochroman-4- carboxylate and this amino acid is dicomposed to give a mixt. of 6- fluoro-4-chromanone and 6-fluoro4-chloroiminochromanone. The mixt. of 6-fluoro-4-chromanone and 6-fluoro-4-chlorominochromanone is hydrogenated to give 6-fluoro4-chromanone.