反应详情

4-(=- 1)piperazine dihydrobromide may be prepared in the following manner: the experiment is carried out as in Example 8 for the preparation of 4-(4hydroxyphenyl)piperazine dihydrobromide, starting with 4-(2-methoxypheny)piperazine (25 g) and 47% aqueous solution of hydrdromic acid (360 cc). The mixture is heated at boiling point for 9 hours, the cooled to a temperature close to 20° C. Stirring is maintained for 15 hours at this temperature, then the mixture is concentrated at 40° C underreduced pressure (20 mm g; 2.7 kPa). The residual oil is redissolved in acetonitrile (40 cc) and isopropyl oxide (40 cc); the precipitate formed is separated by filtration, washed with oxide (2×50 cc). 4-(2-Hydroxyphenyl)piperazine dihydrobromide (m.p.: 235° C.) (18g) is obtained, which is used in the crude state in the subsequent syntheses.

1. temperatureThe mixture is heated
2. customfor 9 hours
3. temperaturethe cooled to a temperature
4. customclose to 20° C
5. temperatureis maintained for 15 hours at this temperature
6. concentrationthe mixture is concentrated at 40° C underreduced pressure (20 mm g; 2.7 kPa)
7. dissolutionThe residual oil is redissolved in acetonitrile (40 cc)
8. customthe precipitate formed
9. customis separated by filtration
10. washwashed with oxide (2×50 cc)