Triethylamine → [(E)-(2-propan-2-ylpyrazolo[1,5-a]pyridin-3-yl)methylideneamino]urea

Participants

Reaction Steps

A mixture of 2-isopropylpyrazolo[1,5-a]pyridine-3-carbaldehyde (0.5 g, 1 equivalent), semicarbazide hydrochloride (0.35 g, 1.2 equivalents), and triethylamine (0.4 mL, 1.1 equivalent) in 5 mL of methanol was reflux for 30 minutes. The solution was concentrated and the crude solids produced were extracted with THF, and the mixture was filtered through a 1 inch thick layer of sodium sulfate on top of a thin pad of silica gel to remove the ammonium salt. The filtrate was concentrated and the solid deposited was recrystallized from THF and hexanes to give (E)-2-((2-isopropylpyrazolo[1,5-a]pyridin-3-yl)methylene)hydrazinecarboxamide (0.46 g, 70% yield) as a yellow solid. Compound 1074.

Provenance & Evidence