反应详情

2.1 g of N,N'-dicyclohexylcarbodiimide are added to a solution of 2.5 g of 1-(4-nitrophenyl)-1,2-cyclopropanedicarboxylic acid in 50 ml of tetrahydrofuran and the mixture is stirred for 1 hour at room temperature. A solution of 0.83 ml of propylamine and 10 ml of tetrahydrofuran is then added dropwise at room temperature to the resultant suspension. The mixture is then stirred at room temperature until reaction is complete. The solvent is evaporated off, the residue is taken up in water and 1 equivalent of sodium hydroxide solution, and the precipitated urea is removed by filtration. The filtrate is acidified with 1 equivalent of hydrochloric acid and extracted twice with methylene chloride. The organic phases are washed once with water, dried over magnesium sulfate and concentrated. Recrystallisation of the residue from ethyl acetate/ether/petroleum ether affords white crystals of the title compound (b) with m.p. 154°-155° C. and Rf=0.45 on thin-layer silica gel plates in the system methylene chloride/methanol/glacial acetic acid (40:5:1).

1. stirringThe mixture is then stirred at room temperature until reaction
2. customThe solvent is evaporated off
3. extractionextracted twice with methylene chloride
4. washThe organic phases are washed once with water
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated
7. customRecrystallisation of the residue from ethyl acetate/ether/petroleum ether