PALLADIUM-CATALYSED COUPLING OF PYRAZOLE AMIDES Russian patent published in 2018 - IPC C07D471/04 

FIELD: chemistry.

SUBSTANCE: invention relates to a process for the preparation of imidazo[1,2-a]pyridine compounds of formula (I), where R¹ is C_1-4-alkoxy or NR⁴R⁵, where R⁴ and R⁵ are independently C_1-4-alkyl, or R⁴ and R⁵ together with the nitrogen atom to which they are attached, form a saturated 4- to 6-membered heterocyclic ring which may contain one additional heteroatom selected from oxygen; R² is C_1-4-alkyl, C_1-4-alkoxycarbonyl, halogen, phenyl which is optionally substituted with halogen, or is NR⁴R⁵, where R⁴ and R⁵ together with the nitrogen atom to which they are attached, form a saturated 6-membered heterocyclic ring which may contain one additional heteroatom selected from oxygen; R³ is C_1-4-alkyl, and X is nitrogen or CH; according to which the pyrazolecarboxamide derivative of formula II is reacted with a halogen derivative of imidazo[1,2-a]pyridine of formula III, where Y is halogen, in the presence of a palladium catalyst, a base selected from alkali metal carbonates, and an organic solvent. I, II, III.

EFFECT: technical result: a novel method for the preparation of imidazo[1,2-a]pyridine derivatives of formula (I) with high selectivity and high yield has been developed.

10 cl, 2 tbl, 13 ex