反应详情

6-Isopropyl-3 (2H)-pyridazinone (3.30 g) and phosphorus oxychloride (15.0 ml) were heated for 1 hour under reflux. After an excess of phosphorus oxychloride was distilled away, ice-water (200 ml) was added to the residues which were then adjusted to pH 6 with 20% aqueous sodium hydroxide solution. The reaction solution was extracted 3 times with ethyl acetate, and the extracts were combined, dried over anhydrous magnesium sulfate and concentrated. The residues were purified by silica gel column chromatography (ethyl acetate:chloroform=1:2) to give the title compound as pale red crystals. The yield was 1.60 g (40.8% based on 5-methyl-4-oxohexanoic acid). mp 32-33° C.

1. temperatureunder reflux
2. distillationAfter an excess of phosphorus oxychloride was distilled away
3. additionice-water (200 ml) was added to the residues which
4. extractionThe reaction solution was extracted 3 times with ethyl acetate
5. dry with materialdried over anhydrous magnesium sulfate
6. concentrationconcentrated
7. customThe residues were purified by silica gel column chromatography (ethyl acetate:chloroform=1:2)