| abstract |
The invention relates to a new process for the preparation of substituted anthraquinones represented by the general formula (I): (CF DRAWING IN BOPI) in which R represents a hydrogen atom or a linear or branched alkyl group of 1 to 5 atoms of carbon, a chloromethyl group, a -COCl group, a -COOR 'group or a -CH2 OR' group where R ′ is a hydrogen atom or a linear or branched alkyl group of 1 to 5 carbon atoms, R1 represents an atom of hydrogen, a hydroxyl group, linear or branched alkoxy of 1 to 5 carbon atoms, or acyloxy of 1 to 5 carbon atoms, and R2 represents a hydrogen atom, by Diels-Alder reaction between a 1, 4 -naphthoquinone of general formula (II): (CF DRAWING IN BOPI) in which R1 is as above, and X represents a hydrogen or halogen atom, and an acyclic diene of formula (III): CH2 = CR - CH = CH - OR3 in which R is as above, and R3 represents a silyl group of formula -Si (R4) 3 where R4 is a group linear or branched alkyl of 1 to 5 carbon atoms, followed by an oxidative deprotection reaction using Jones' reagent, to obtain the substituted anthraquinone of general formula (I). Application to the preparation of rheins useful in pharmacy |