Triethylamine → 1-Boc-4-(4-Nitrophenyl)piperazine

Temperature

120 °C

To a solution of N-tert-butyloxycarbonylpiperazine (5 g) in anhydrous dimethylformamide (75 ml) containing triethylamine (7.4 ml), was added 1-fluoro-4-nitrobenzene (3.81 g). The solution was heated at 120° C. for 5 h then the solvent was evaporated in vacuo and the residue partitioned between ethyl acetate (50 ml) and water (50 ml). The organic layer was separated and the aqueous phase washed with ethyl acetate (3×50 ml). The combined organic layers were washed with water (2×50 ml), dried (Na2SO4) and evaporated in vacuo. The residue was triturated with ether and the resultant yellow solid filtered off. The solid was then chromatographed on silica gel, using a gradient elution of 0→1% methanol in dichloromethane to afford the title compound (4.45 g) as a yellow solid. 1H NMR (360 MHz, CDCl3) δ 1.49 (9H, s), 3.40-3.43 (4H, m), 3.59-3.62 (4H, m), 6.82 (2H, dd, J=9 and 1.8 Hz), 8.13 (2H, dd, J=9 and 1.8 Hz). MS (CI, NH3) 307 (M+).

1. customthe solvent was evaporated in vacuo
2. customthe residue partitioned between ethyl acetate (50 ml) and water (50 ml)
3. customThe organic layer was separated
4. washthe aqueous phase washed with ethyl acetate (3×50 ml)
5. washThe combined organic layers were washed with water (2×50 ml)
6. dry with materialdried (Na2SO4)
7. customevaporated in vacuo
8. customThe residue was triturated with ether
9. filtrationthe resultant yellow solid filtered off
10. customThe solid was then chromatographed on silica gel
11. washa gradient elution of 0→1% methanol in dichloromethane

ORD record

ord-c4f1a85cc81941599b4f19906b647ac6

Source dataset

uspto-grants-1996_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05556969