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ChemicalBook CAS DataBase List 2-Bromo-5-fluoroaniline
1003-99-2

2-Bromo-5-fluoroaniline synthesis

8synthesis methods
A preparation method of 2-Bromo-5-fluoroaniline is as follows: methanol, 2-bromo-5-fluoronitrobenzene, W-4 type Raney nickel and bromine inhibitor are put into a hydrogenation kettle to carry out hydrogenation reaction. After the reaction is completed, the reaction solution is filtered under nitrogen protection. The filtered filtrate is then distilled under reduced pressure to remove methanol, and n-hexane is added. Then, the product is washed with process water, and after washing, the product is allowed to stand and separate. Then, the organic phase is cooled and crystallized, an off-white to brownish-yellow solid is precipitated, and a wet product is obtained by suction filtration. The wet product is dried to obtain the finished product 2-Bromo-5-fluoroaniline.
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Yield:1003-99-2 100%

Reaction Conditions:

Stage #1:2-bromo-5-fluoronitrobenzene with iron;acetic acid in ethanol at 20; for 2.08333 h;Heating / reflux;
Stage #2: with sodium hydroxide in diethyl ether;water

Steps:


2-Bromo-5-fluorobenzenamine; To a solution of 1-bromo-4-fluoro-2-nitrobenzene (5.0 g, 22.7 mmol) in HOAc/EtOH (20 mL/20 mL) was added iron powder in one portion at room temperature. The mixture was bubbled with N2 for 5 min, and then refluxed for 2 hrs. Partial of the solvents were removed on rotary vacuum, then the residue was partitioned between aqueous NaOH (10N, 200 mL) and Et2O (200mL). After separation, the organic phase was washed with H2O(50 mL), brine (50 mL), dried on MgSO4, and concentrated on rotary vacuum to afford the expected product, as an light tan oil (quantitative yield), which was pure enough to be used in next step without further purification; 1H NMR (400 MHz, CDCl3) δ ppm 4.15 (s, 1 H), 6.34 (td, J=8.44, 2.77 Hz, 1 H) ,6.46 (dd, J=10.20, 2.90 Hz, 1 H), 7.31 (dd, J=8.81, 5.79 Hz, 1 H); Mass spec. 189.94 (MH+), Calc. for C6H5BrFN 188.96.

References:

Bristol-Myers Squibb Company US2007/259850, 2007, A1 Location in patent:Page/Page column 95-96

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