Ethyl 2-cyano-3-ethoxy-2-butenoate → Ethyl 7-amino-mesityl-2,5-dimethylpyrazolo[1,5-a]pyrimidin-6-carboxylate

Participants

Reaction Steps

Concentrated dihydrochloric acid (0.1 mL) was added to a solution of 4-mesityl-3-methyl-1H-5-pyrazoleamine (2.5 g, 11.61 mmol) and ethyl 2-cyano-3-ethoxy-2-butenoate (2.13 g, 11.61 mmol) in ethanol (30 mL), followed by heating under reflux for 18 hours. The reaction mixture was evaporated as it was. Then, water was added and a 5N aqueous solution of sodium hydroxide was added under ice-cooling, to neutralize. Further, the mixture was extracted with ethyl acetate, and the organic layer was washed with brine, dried over anhydrous magnesium sulfate and evaporated. The residue was purified by silica gel column chromatography (15% ethyl acetate/hexane), to give the title compound (835 mg).

Provenance & Evidence