反应详情

To a suspension of 10 g of 3-(2,3-dichlorophenyl)-4-cyanopyrrole in 35 ml of ethanol are added 5 ml of a 38% aqueous solution of formaldehyde and 0.4 ml of acetic acid. With stirring, 8.3 ml of 2,6-dimethylmorpholine (mixture of cis/trans isomers) are added dropwise, the temperature rising to 37° C. Then 14 ml of water are added dropwise and the solution is left to stand overnight at room temperature. Water is again added until the onset of turbidity. The batch is then cooled in an ice bath and the product begins to crystallise. The crystals are isolated by filtration and dried over phosphorus pentoxide, affording 8.5 g of brown crystals of the desired product as a mixture of cis/trans isomers. Melting point: 91°-97° C. The mother liquor is concentrated to a small volume and the residue is extracted with ethyl acetate and water. The organic phase is separated, washed twice with a semisaturated solution of sodium chloride, dried over sodium sulfate and concentrated. The residue is recrystallised from ether/petroleum ether, affording 0.8 g of a homogeneous diastereoisomer of the above product in the form of colourless crystals. Melting point: 102°-104° C.

1. customrising to 37° C
2. waitthe solution is left
3. temperatureThe batch is then cooled in an ice bath
4. customto crystallise
5. customThe crystals are isolated by filtration
6. dry with materialdried over phosphorus pentoxide