反应详情

The 4-[5-(4-methylphenyl)-2-pyridyl]-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile used as the starting material was prepared as follows: (A) 9.5 g of 4-(5-amino-2-pyridyl)-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile were dissolved in 150 ml of acetic acid and 100 ml of water. 3.16 g of sodium nitrite in 10 ml of water were added at such a rate as to keep the temperature below 5° C. After 15 minutes 23 g of potassium iodide in 20 ml of water were added and the mixture was stirred at room temperature for 1 hour. The mixture was then poured into 1.1 of 2M sodium hyroxide solution and extracted with ethyl acetate. The organic extract was dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:4) for the elution to give 4.78 g of 4-(5-iodo-2-pyridyl)-2,2-dimethyl-2H-1 -benzopyran-6-carbonitrile which was used without further purification. (B) 440 mg of 4-(5-iodo-2-pyridyl)-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile, 386 mg of p-tolyltrimethyltin, 440 mg of lithium chloride and 16 mg of bis(triphenylphosphine)palladium dichloride in 4 ml of dimethylformamide were heated at 100° C. for 2 hours. After cooling to room temperature 10% aqueous ammonia and ethyl acetate were added, the phases were separated and the aqueous phase was back-extracted with ethyl acetate. The combined organic phases were dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:4) for the elution to give 268 mg of 4-[5-(4-methylphenyl)-2-pyridyl]-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile which was used without further purification.

1. customwas prepared
2. customthe temperature below 5° C
3. extractionextracted with ethyl acetate
4. extractionThe organic extract
5. dry with materialwas dried over sodium sulphate
6. customevaporated
7. customThe residue was chromatographed on silica gel
8. washfor the elution