

A CONVENIENT SYNTHESIS OF METHYL 4-OXO-4,5-DIHYDROPYRAZOLO[1,5-a]PYRAZINE-7-CARBOXYLATES AND CORRESPONDING CARBOXYLIC ACIDS

Abstract
Pyrazolo[1,5-a]pyrazin-4(5H)-ones react regioselectively with N-iodosuccinimide in the presence of N-methylmorpholine to form 7-iodo derivatives. Their carbonylation catalyzed with Pd(dppf)Cl2 under pressure in MeOH solution yielded methyl 4-oxo-4,5-dihydropyrazolo[1,5-a]pyrazine-7-carboxylates, which were transformed into the corresponding carboxylic acids by alkaline hydrolysis.
Keywords
7-iodopyrazolo[1,5-a]pyrazine-4(5H)-ones; palladium-catalyzed carbonylation; methyl-4-oxo-4,5-dihydropyrazolo[1,5-a]pyrazine-7-carboxylates; 4-oxo-4,5-dihydropyrazolo[1,5-a]pyrazine-7-carboxylic acids.
Latvian Institute of Organic Synthesis - Aizkraukles iela, 21, Riga, LV-1006, Latvia - hgs@osi.lv