Reaction #49694

Reaction equation

(-)-8-chloro-6,11-dihydro-11-(4-piperazinyl)-5H-benzo[5,6]cyclohepta-[1,2-b]pyridine

4-pyridylcarbinol N-oxide

carbon tetrabromide

triethylamine

triphenylphosphine

→

(-)-8-chloro-6,11-dihydro-11-[4 -(4-pyridinylmethyl)-1-piperazinyl]-5h-benzo[5,6]cyclohepta-[1,2-b]pyridine

Yield 45.3%

Solvents

methylene chloride

methylene chloride

Conditions

Workup

1. 1
   Washwashed once with 0.5M aqueous sodium bicarbonate
2. 2
   DryingThe organic portion was dried over sodium sulfate
3. 3
   Filtrationfiltered
4. 4
   Concentrationconcentrated in vacuo
5. 5
   OtherThe residue was purified via flash chromatography (4% methanol saturated with ammonia in methylene chloride)

Procedure

To a mixture of 188 mg (1.50 mmol) of 4-pyridylcarbinol N-oxide and 497 mg (1.50 mmol) of carbon tetrabromide in 12 mL of dry methylene chloride at room temperature and under an argon atmosphere was added in one portion 393 mg (1.50 mmol) of triphenylphosphine. After 40 minutes, 313 mg (0.997 mmol) of (-)-8-chloro-6,11-dihydro-11-(4-piperazinyl)-5H-benzo[5,6]cyclohepta-[1,2-b]pyridine was added followed by 209 mL (1.57 mmol) of triethylamine. The reaction mixture was then allowed to stir at room temperature for 3 hr, after which it was taken up in methylene chloride and washed once with 0.5M aqueous sodium bicarbonate and then brine. The organic portion was dried over sodium sulfate, filtered and concentrated in vacuo. The residue was purified via flash chromatography (4% methanol saturated with ammonia in methylene chloride) to provide 183 mg of (-)-8-chloro-6,11-dihydro-11-[4 -(4-pyridinylmethyl)-1-piperazinyl]-5h-benzo[5,6]cyclohepta-[1,2-b]pyridine, N-oxide as a glass: MS (CI) m/z 421 (M+ +1);

Source