| abstract |
A process for the preparation of compounds of formula (I), which process comprises reacting a compound of formula (II), in an inert organic solvent, optionally in the presence of a base, with a compound of formula (IV), (IVa) or (IVb), and optionally converting the resulting compound of formula (I) wherein G is a metal ion equivalent or an ammonium cation, by salt conversion into the corresponding salt of formula (I) wherein G is a sulfonium or phosphonium cation, or by treatment with a Brönsted acid into the corresponding compound of formula (I) wherein G is hydrogen, and "in situ' conversion of compounds of formula (I) with an electrophile of formula (XII) or (XIId) G0-L (XII) or R32-N=C=X3 (XIId), optionally in the presence of an acid-binding agent or a catalyst, to the compounds of formula (Ia). |