Patent ID: 8765942

Claim:
A process for preparing a compound corresponding to formula (I) below: in which each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 and R 10 is chosen, independently of the others, from the group constituted of: a hydrogen atom, saturated or unsaturated, linear or branched C 1 -C 6 alkyl groups, or C 3 -C 6 cycloalkyl groups, optionally substituted with one or more functions chosen from a halogen atom, and a C 1 -C 6 alkoxy, C 1 -C 6 alkoxycarbonyl or —CONH 2 function, aryl groups optionally substituted with one or more functions chosen from: a C 1 -C 4 alkyl, a halogen atom, and a C 1 -C 6 alkoxy, C 1 -C 6 alkyloxycarbonyl or —CONH 2 function, X − represents an organic or inorganic anion, wherein the process comprises at least one step during which a compound of formula (II): in which R represents a group chosen from: a phenyl or benzyl group, optionally substituted with one or more functions chosen from: a C 1 -C 4 alkyl, a halogen atom, a C 1 -C 4 haloalkyl and a nitro group, a phenyloxy or benzyloxy group optionally substituted on the aromatic nucleus with one or more functions chosen from: a C 1 -C 4 alkyl, a halogen atom, a C 1 -C 4 haloalkyl and a nitro group, Z represents an atom chosen from O and S, is subjected to a purification step, and thereafter reacting that compound of formula (II) with a quinone to produce the compound of formula (I), and wherein the reaction of compound (II) with a quinone to produce compound (I) is achieved in a one-pot process step.