反应详情

温度

80 °C

A 2 L, 3 necked, round bottom flask was charged with 2-aminoethanol (240 gm; 3.93 moles) and heated to 80° C. Methyl 3,5-dichloro-4-hydroxybenzoate (432 gm; 1.96 moles) was added in portions through a powder funnel. The resulting amber solution was heated to 145° C. and the liberated methanol distilled into a Dean Stark trap. The reaction required about 3.5 hrs. Upon completion, the solution was cooled to 90°-100° C. and dissolved in 1.95 L H2O. The aqueous solution was cooled to 25° C., placed in an ice bath and made slightly acidic with concentrated hydrochloric acid (196 ml; 2.35 moles). The product precipitated and filtration afforded a white solid. After drying at 50° C. in a vacuum oven, the product darkened slightly. The crude material (384.4 gm; 78.8%) was ground and passed through a No. 20 mesh screen to produce 3,5-dichloro-4-hydroxy-N-(2-hydroxyethyl)benzamide as a cream colored solid (m.p. 174°-178° C.) which is suitable for use in the next step.

1. temperatureThe resulting amber solution was heated to 145° C.
2. distillationthe liberated methanol distilled into a Dean Stark trap
3. customThe reaction required about 3.5 hrs
4. temperatureUpon completion, the solution was cooled to 90°-100° C.
5. temperatureThe aqueous solution was cooled to 25° C.
6. customplaced in an ice bath
7. customThe product precipitated
8. filtrationfiltration
9. customafforded a white solid
10. customAfter drying at 50° C. in a vacuum oven