Process for the preparation of chiral 3,4-epoxy benzopyrans
申请人:Beecham Group p.l.c.
公开号:EP0430621A2
公开(公告)日:1991-06-05
A process for the preparation of a compound of formula (A)' or (A)'':
which process comprises the base treatment of a quaternary ammonium salt of a compound of formula (D):
wherein the NH₂ and OH moieties are trans and are (R,S) or (S,R), respectively.