反应详情

The piperazineacetic acid compound of formula (XXIV) employed in the synthesis above and many others in this application was synthesized as follows: Twelve milliliters (50 mmol) of N,N′-dibenzylethylene-diamine, 14 mL (100 mmol) of Et3N and 250 mL toluene were combined at 0° C., and 7 mL (50 mmol) of methyl 4-bromocrotonate (7 mL, 50 mmol) was added. The reaction was slowly warmed to room temperature, stirred for 24 hours, filtered, concentrated in vacuo to a residue and treated with 10% aqueous HCl (300 mL). The mixture was filtered again and the filtrate washed with ethyl acetate (2×100 mL). The filtrate was made basic with K2CO3 and extracted with ethyl acetate (3×150 mL). The combined extracts were washed with brine, dried over MgSO4 and concentrated in vacuo to give 13.7 g of methyl 1,4-dibenzylpiperazine-2-acetate. 1H NMR (CDCl3) δ 2.28-2.50 (m,4), 2.5-2.75 (m,4), 3.1 (bs, 1), 3.42 (d,2), 3.52 (d,1), 3.6 (s,3), 3.75 (d,1), 7.15-7.35 (m,1).

1. customwas synthesized
2. customwere combined at 0° C.
3. filtrationfiltered
4. concentrationconcentrated in vacuo to a residue
5. additiontreated with 10% aqueous HCl (300 mL)
6. filtrationThe mixture was filtered again
7. washthe filtrate washed with ethyl acetate (2×100 mL)
8. extractionextracted with ethyl acetate (3×150 mL)
9. washThe combined extracts were washed with brine
10. dry with materialdried over MgSO4
11. concentrationconcentrated in vacuo