Process for preparing substituted 5-fluoro-1H-pyrazolopyridines
View Patent ↗The present application relates to a novel and efficient process for preparing novel substituted 5-fluoro-1H-pyrazolopyridines of the formula (VI) which are suitable as an intermediate for production of medicaments and for production of medicaments for treatment and/or prophylaxis of cardiovascular disorders. More particularly, the 5-fluoro-1H-pyrazolopyridines of the formula (VI) are suitable for preparation of the compound of the formula (I) which serves for production of medicaments, for production of medicaments for treatment and/or prophylaxis of cardiovascular disorders.
1. A process for preparing compounds of formula (VI),
the method comprising:
reacting an ester of formula (IVa)
in which
T 1 is (C 1 -C 4 )-alkyl
with formamide, to give a compound of formula (V):
and dehydrating the compound of formula (V) to give the compound of formula (VI).
2. The process of claim 1 , wherein the ester of the formula (IVa) is prepared by cyclizing the 5-aminopyrazole derivative (IIa)
in which
T 1 is (C 1 -C 4 )-alkyl
in the presence of an alkali metal salt and an acid with an aldehyde of formula (III)
in which R 1 and R 2 are each independently methyl, ethyl, isopropyl, phenyl or, together with the nitrogen atom to which they are bonded, are
3. The process of claim 2 , wherein the aldehyde of formula (III) used in the cyclization reaction is a compound of formula (IIIa)