反应详情

41 g of α-methyl-3,4-dichlorobenzylhydrazine, dissolved in absolute ethanol, were added dropwise to a solution of 31.8 g of β-amino-β-ethoxyacrylic acid ethyl ester and 1.5 g of p-toluenesulphonic acid in 150 ml of ethanol at room temperature under nitrogen gas. After stirring for 2 hours and standing overnight, the reaction solution was concentrated as far as possible on a rotary evaporator. The residue which remained was dissolved in 2 N sodium hydroxide solution. Any unconverted starting products or by-products were extracted with ether. The aqueous phase was then brought to pH 5 with acetic acid. The oil thereby produced was taken up in methylene chloride and the organic phase was dried over Na2SO4. After evaporating off the solvent, the reaction product crystallized out. It was recrystallized from methanol. Melting point 127°-129° C; yield 21 g (38.5% of theory).

1. waitstanding overnight
2. concentrationthe reaction solution was concentrated as far as
3. custompossible on a rotary evaporator
4. dissolutionThe residue which remained was dissolved in 2 N sodium hydroxide solution
5. extractionwere extracted with ether
6. customThe oil thereby produced
7. dry with materialthe organic phase was dried over Na2SO4
8. customAfter evaporating off the solvent
9. customthe reaction product crystallized out
10. customIt was recrystallized from methanol