| abstract |
The present invention relates to a novel process for the preparation of a compound of formula (I), or a pharmaceutically acceptable salt or solvate thereof, wherein R 1 and R 2 are independently alkyl or alkoxy, wherein said alkyl or alkoxy may be optionally substituted with up to two substituents; R 15 is hydrogen, alkyl, or - (CH 2) q - (C 6 -C 10) aryl, wherein q is an integer from 0 to 9. In the process, a compound of formula (II) wherein R1, R2 and R15 are as defined for compounds of formula (I) and G is a blocking group of the formula -C (OH) R3R4 or -SiR3R4R5, R3, R4 and R5 are each is independently alkyl, (a) reacting a alkali metal or alkaline earth metal with a hydroxide in a solvent containing a hydroxy substituted subgroup, wherein G is -C (OH) R 3 R 4, or (b) a tetra- (C 1 -C 6) alkylammonium. reaction with a fluoride compound in an aprotic solvent wherein G is -SiR3R4R5. The invention also relates to intermediates of formula (II). SHE |