Potassium Carbonate → Methyl 5-chloro-4-(1-methyl-1H-pyrazol-5-yl)thiophene-2-carboxylate

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Reaction Steps

A solution of methyl 4-bromo-5-chloro-2-thiophenecarboxylate (2.56 g, 10.00 mmol)[prepared according to Example 95], 5-(5,5-dimethyl)-1,3,2-dioxaborinane-2-yl)-1-methyl-1H-pyrazole (3.88 g, 20.0 mmol)[prepared according to Preparation 7], potassium carbonate (4.15 g, 30.0 mmol) and 1,1′-bis(diphenylphosphino)ferrocenedichloro palladium (II) dichloromethane complex (0.073 g, 0.1 mmol) in 1,4-Dioxane (12 mL) and water (3.00 mL) were heated at 80° C. in a sealed tube. After 3 hrs, another batch of 5-(5,5-dimethyl)-1,3,2-dioxaborinane-2-yl)-1-methyl-1H-pyrazole (1.94 g, 10.0 mmol) and 1,1′-bis(diphenylphosphino)ferrocenedichloro palladium (II) dichloromethane complex (0.073 g, 0.1 mmol) were added. After 2 hr, the mixture was concentrated and purified by silica gel eluting with 0-35% ethyl acetate/hexane affording the title compound as a yellow solid (1.74 g, 3.35 mmol, 34%): LC-MS (ES) m/z 257 (M+H)+.

Provenance & Evidence