| abstract |
The invention relates to a process for the preparation of a compound of formula I, which process comprises (a) reacting a compound of formula II, wherein X is chloro or bromo, with an organometallic species to III, reacting the halobenzyne of formula III so formed with IV, wherein R1 and R2 are hydrogen or C<sub>1</sub>-C<sub>6</sub>alkyl; to V (b) hydrogenating V in the presence of a metal catalyst to VI (c)ozonising VI to VII (d) converting VII in the presence of a phosphane and CCl<sub>4</sub> or CHCl<sub>3</sub> to VIII, and either (e1)reacting VIII with NH<sub>3</sub> in the presence of a catalyst to IX and (f) reacting IX in the presence of a base with the compound of formula X, to the compound of formula I; or (e2)reacting the compound of formula VIII in the presence of a solvent, a base, a copper catalyst and at least one ligand with Xa, to the compound of formula I. |