Preparation of (r)-n-(3,4-difluoro-2 (2-fluoro-4-iodophenylamino)-6 methoxyphenyl)-1-(2,3 dihydroxypropyl)cyclopropane-1 sulfonamide and (s)- n-(3,4-difluoro-2 (2-fluoro-4-iodophenylamino)-6 methoxyphenyl)-1-(2,3 dihydroxypropyl)cyclopropane-1 sulfonamide

Abstract

The present invention relates to a process for preparing a compound of formula (I-a) or (I-b): wherein the process with regard to formula (I-a) comprises contacting 5,6-difluoro-Nl-(2-fluoro-4iodophenyl)-3-methoxybenzene-1,2-diamine with a compound of formula (Il-a): and wherein the process with regard to formula (I-b) comprises contacting 5,6-difluoro-Nl-(2-fluoro-4iodophenyl)-3-methoxybenzene-1,2-diamine with a compound of formula (Il-b): wherein R1 is H or an alcohol protecting group; R2 is H or an alcohol protecting group; or R1 and R2 together with the oxygen atoms to which they are attached form a cyclic 1,2-diol protecting group. The advantageous effects of the claimed process is the preparation o f a compound, in which the configuration of the chiral centre is determined in starting material before the condensation reaction. The compound as prepared by the claimed process possesses inhibitory properties against MEK enzymes and are o f therapeutic value.