反应详情

To a solution of 2-phenylpyrazine (11.64 g, 74.53 mmol) in acetic acid (58.2 mL) was added palladium acetate Pd(OAc)2 (2.33 g, 9.94 mmol). The mixture was hydrogenated at 50 psi for 4 h. After the reaction was complete, the catalyst was filtered off and rinsed with a small portion of acetic acid. The filtrate was concentrated under house vacuum to give a brown-black solid which was suspended in deionized water (300 mL) and adjusted to pH 13 with 20% NaOH solution. The product was extracted from aqueous solution with EtOAc (200 mL, 3×), dried over MgSO4, filtered and evaporated to dryness to give 2-phenylpiperazine (7.2 g). An additional 1.6 g of 2-phenylpiperazine was obtained by evaporating the aqueous fraction to a solid and triturating the solid with CH2Cl2. Total yield of 2-phenyl-piperazine was 73%. The crude material was crystallized from EtOAc and hexane for characterization, m.p. 86°-88° C.; FAB MS [M+1]+ 163;

1. filtrationthe catalyst was filtered off
2. washrinsed with a small portion of acetic acid
3. concentrationThe filtrate was concentrated under house vacuum
4. customto give a brown-black solid which
5. extractionThe product was extracted from aqueous solution with EtOAc (200 mL, 3×)
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. customevaporated to dryness