| abstract |
A process for the manufacture of the compound of formula I ** (See formula) ** in which R is H or a salt thereof, said process comprising the reaction of the compound of formula I-1 ** (See formula) ** in which X is bromine, chlorine or fluorine, with the compound of formula I-2 ** (See formula) ** in which R is H, or a salt of said compound of formula I-2, said reaction which is carried out in the presence of a base in a polar aprotic organic solvent or a polar mixture of aprotic organic solvents, and, when X is bromine or chlorine, in the presence of tetra-n-butyl ammonium fluoride hydrate or fluoride cesium. |