反应详情

5-(3-Amino-2-hydroxy-phenyl)-furan-2-carboxylic acid hydrobromide 9c (124 mg, 0.41 mmol) was dissolved in 1.4 mL of hydrochloric acid (1 N) upon cooling by an ice-water bath, followed by dropwise addition of 0.5 mL of aqueous sodium nitrite (32 mg, 0.45 mmol). After the mixture was stirred for 20 minutes, 5-methyl-2-(1,1,3,3-tetramethyl-indan-5-yl)-2,4-dihydro-pyrazol-3-one 19d (100 mg, 0.37 mmol) was added. The mixture was adjusted to pH 8 with saturated aqueous sodium bicarbonate. The generated bubbles were quenched with 2 mL of ethanol. The reaction mixture was warmed up to room temperature and reacted overnight. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filter cake was dissolved in 10 mL of water. The mixture was adjusted to pH 3˜4 with concentrated hydrochloric acid, filtered and dried. The residue was purified by silica gel column chromatography to obtain the title compound 5-(2-hydroxy-3-{N′-[3-methyl-5-oxo-1-(1,1,3,3-tetramethyl-indan-5-yl)-1,5-dihydro-pyrazol-4-ylidene]-hydrazino}-phenyl)-furan-2-carboxylic acid 25 (22 mg, yield 11.9%) as a red solid.

1. temperatureupon cooling by an ice-water bath
2. customThe generated bubbles were quenched with 2 mL of ethanol
3. customreacted overnight
4. filtrationThe mixture was filtered
5. dissolutionthe filter cake was dissolved in 10 mL of water
6. filtrationfiltered
7. customdried
8. customThe residue was purified by silica gel column chromatography