5-TERT-BUTYL-1H-PYRAZOLE-3-CARBALDEHYDE synthesis

Yield:865138-11-0 69%

Reaction Conditions:

with manganese(IV) oxide in tetrahydrofuran at 20; for 3 h;

Steps:

66

To a solution of ethyl 3-tert-butyl-1H-pyrazole-5-carboxylate (4.0 g, 20.4 mmol) in tetrahydrofuran (50 mL) was added lithium aluminum hydride (800 mg, 21.1 mmol) by small portions at 0°C, and the mixture was allowed to warm to room temperature and stirred for 1 hr. Sodium sulfate decahydrate (7.6 g) was added to the reaction mixture, and the mixture was stirred at room temperature for 30 min. The insoluble material was filtered off. The filtrate was concentrated and the residue was dissolved in tetrahydrofuran (100 mL). Manganese dioxide (10.0 g) was added, and the mixture was stirred at room temperature for 3 hr. The insoluble material was filtered off, and the filtrate was concentrated to give the title compound (2.13 g, yield 69%) as colorless crystals. ¹H NMR (CDCl₃) δ: 1.37(9H, s), 6.65(1H, s), 9.95(1H, s).

References:

EP1731505,2006,A1 Location in patent:Page/Page column 50