反应详情

To a solution of methylamine hydrochloride (2.0 g, 25 mmol) at rt in dioxane (60 ml) was added trimethyaluminium (2 M in toluene, 12.3 ml, 25 mmol) and stirred for 2 hrs at rt. Then 1-(2-methoxyethyl)-4-nitro-1H-pyrazole-3-carboxylic acid ethyl ester (2.0 g, 8.0 mmol; example 4, step 2) was added. The mixture was heated to 100° C. and stirring was continued overnight. The mixture was cooled to rt, then 2 ml water was added and stirring was continued for 15 min. Some MgSO4 was added and stirring was continued for 15 min. The mixture was filtered, washed with CH2Cl2 and concentrated. The crude product was purified by silica gel chromatography using a cyclohexane/EtOAc gradient, providing the title compound (302 mg, 16%) as orange oil.

1. temperatureThe mixture was heated to 100° C.
2. stirringstirring
3. waitwas continued overnight
4. temperatureThe mixture was cooled to rt
5. stirringstirring
6. waitwas continued for 15 min
7. stirringstirring
8. waitwas continued for 15 min
9. filtrationThe mixture was filtered
10. washwashed with CH2Cl2
11. concentrationconcentrated
12. customThe crude product was purified by silica gel chromatography