反应详情

To a solution of 0.32 mol ethyl 1,4-dihydro-2-methyl-4-phenyl-3-pyridinecarboxylate in 50 ml of methylene chloride was added 16 g (0.5 mol) of sulfur. The temperature of the well-stirred dark solution was raised over a period of about 30 minutes to 170°-180° C. When the development of hydrogen sulfide had subsided, the reaction mixture was cooled to room temperature, taken up in toluene, and filtered through Celite filter aid. The filtrate was concentrated under vacuum and the residue chromatographed on silica gel, eluting with ethyl acetate/hexane to yield 61.7 g of ethyl 2-methyl-4-phenyl-3-pyridinecarboxylate

1. temperatureThe temperature of the well-stirred dark solution was raised over a period of about 30 minutes to 170°-180° C
2. filtrationfiltered through Celite
3. filtrationfilter aid
4. concentrationThe filtrate was concentrated under vacuum
5. customthe residue chromatographed on silica gel
6. washeluting with ethyl acetate/hexane