5-amino-6-chloro-2-ethyl-N-(piperidin-4-ylmethyl)imidazo[1,2-a]pyridine-8-carboxamide → 5-amino-6-chloro-2-ethyl-N-{[1-(4-hydroxy-3,3-dimethyl-2-oxobutyl)piperidin-4-yl]methyl}imidazo[1,2-a]pyridine-8-carboxamide

Participants

Reaction Steps

A mixture of 5-amino-6-chloro-2-ethyl-N-(piperidin-4-ylmethyl)imidazo[1,2-a]-pyridine-8-carboxamide (Example 4, step 4, 530 mg, 1.57 mmol) and 4-bromo-2,2-dimethyl-3-oxobutyl trifluoroacetate (Example 6, step 1, 777 mg, 2.67 mmol) in methanol (15 mL) was stirred at room temperature for 5 days. The reaction mixture was concentrated in vacuo. The residue was basified with aqueous potassium carbonate (20 mL) and extracted with dichloromethane (3×30 mL). The combined extract was washed with brine, dried over magnesium sulfate, and evaporated. Flash column chromatography (NH-silica gel) of the residue eluting with dichloromethane/methanol (200:1 to 50:1) afforded a white solid. This was recrystallized from ethanol to afford 173 mg (25%) of the title compound as a white solid.

Provenance & Evidence