US Patent RE41366 Total synthesis of galanthamine, analogues and derivatives thereof

The invention relates to a method for the synthesis of galanthamine, the derivatives and analogues thereof of formula (1) where R1=a hydrogen atom, R2=a hydroxy group, R1 and R2 together form ═O, R3, R4, and R5 independently=a hydrogen atom, a hydroxy group or a (C1-C2)alkoxy group, R6═H, (C1-C12)alkyl, (CH2)nNR7R8, or —(CH2)nN+R7R8R9 where n=1 to 12, Z=two hydrogen atoms, or an oxygen atom and X=an oxygen, sulphur or nitrogen atom, or a —SO, —SO2, or —NR6 group where R6 is as defined above or is an amine protecting group.