反应详情

5-(3-Amino-2-hydroxy-phenyl)-thiophene-2-carboxylic acid hydrobromide 12c (351 mg, 1.11 mmol) was dissolved in 3.7 mL of hydrochloric acid (1 N) upon cooling by an ice-water bath, followed by dropwise addition of 1.5 mL of aqueous sodium nitrite (85 mg, 1.22 mmol). After the mixture was stirred for 20 minutes, 5-methyl-2-(3-methyl-indan-5-yl)-2,4-dihydro-pyrazol-3-one 38f (228 mg, 1 mmol) was added. The mixture was adjusted to pH 8 with saturated aqueous sodium bicarbonate. Then the generated bubbles were quenched with 2 mL of ethanol. The reaction mixture was warmed up to room temperature and reacted for 3 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and 30 mL of water was added to the filter cake. The mixture was adjusted to pH 3˜4 with concentrated hydrochloric acid. The mixture was filtered and the filter cake was dried, and then purified by silica gel column chromatography to obtain the title compound 5-(2-hydroxy-3-{N′-[3-methyl-1-(3-methyl-indan-5-yl)-5-oxo-1,5-dihydro-pyrazol-4-ylidene]-hydrazino}-phenyl)-thiophene-2-carboxylic acid 40 (90 mg, yield 19.0%) as a red solid.

1. temperatureupon cooling by an ice-water bath
2. customThen the generated bubbles were quenched with 2 mL of ethanol
3. customreacted for 3 hours
4. filtrationThe mixture was filtered
5. addition30 mL of water was added to the filter cake
6. filtrationThe mixture was filtered
7. customthe filter cake was dried
8. custompurified by silica gel column chromatography