Pyrazole → HCID 66977306, compound

Participants

Reaction Steps

A mixture of 7-bromo-5-chloro-imidazo[1,2-a]pyridine-2-carboxylate (Intermediate 16) (0.867 g, 2.86 mmol) and pyrazole (0.194 g, 2.86 mmol) was dissolved in DMF (15 mL). Cesium carbonate (1.95 g, 2.1 eq.) was added and the mixture stirred at rt. After 16 hours TLC indicated clean but incomplete reaction and stirring was continued over the weekend. Saturated aqueous NH4Cl (50 mL) was added, resulting in effervescence and a gelatinous precipitate which was then broken up, water (30 mL) added and the solid filtered in vacuo. This material was washed with water and sucked dry to give a tan paste. The filtrate was extracted with EtOAc (100 mL), washed with water (30 mL), brine (30 mL), and set aside. The tan paste was dissolved in EtOAc (200 mL), combined with the filtrate, dried over MgSO4, filtered and evaporated to give a brown residue that crystallized upon standing. Trituration with EtOAc (15 mL) and heptane (50 mL) yielded a yellow powder, 0.363 g (38%). MS: 335, 337 [M+H]+.

Provenance & Evidence