反应详情

A mixture of 1-(4-bromo-3-methylphenyl)ethanone (500 mg) and 4-methylbenzenesulphonic acid hydrazide (437 mg) was heated to reflux in ethanol (15 ml) containing a few 4A molecular sieves for 5 h. On cooling, colourless needles were formed, which were collected by filtration (577 mg). 300 mg of this intermediate hydrazone were dissolved in thionyl chloride (2 ml) and was stirred at 20° for 5 h. The mixture was neutralised with 2N sodium carbonate (40 ml) and extracted with ethyl acetate (2×30 ml). The dried extracts were then evaporated to give a yellow solid. This material was chromatographed on silica eluting with dichloromethane;hexane (1:1) to give the title compound as pale yellow solid (167 mg). T.l.c. ethyl acetate:hexane (1:4) Rf 0.52.

1. temperaturewas heated
2. temperatureOn cooling
3. customcolourless needles were formed
4. filtrationwhich were collected by filtration (577 mg)
5. dissolution300 mg of this intermediate hydrazone were dissolved in thionyl chloride (2 ml)
6. extractionextracted with ethyl acetate (2×30 ml)
7. customThe dried extracts were then evaporated
8. customto give a yellow solid
9. customThis material was chromatographed on silica eluting with dichloromethane