Sodium borohydride → HCID 23312321, compound

HRID 745824Notes

Reaction equation

HRID 745824 reaction equation
[BH4-].[Na+].[I-].[CH3:4][N+:5]1[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=1[C:11]1[O:12][C:13]2[CH:19]=[CH:18][CH:17]=[CH:16][C:14]=2[CH:15]=1>O.CO>[CH3:4][N:5]1[CH2:10][CH2:9][CH2:8][CH2:7][CH:6]1[C:11]1[O:12][C:13]2[CH:19]=[CH:18][CH:17]=[CH:16][C:14]=2[CH:15]=1

Participants

5

Reactant 2

HCID 4311764Sodium borohydrideHCID 23312187HCID 23312187, compound

Product 1

HCID 23312321HCID 23312321, compound

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent2×

Procedure

6.15 g of sodium borohydride dissolved in 50 ml of water is added dropwise in the course of 30 minutes, with stirring and ice-water cooling, to a solution of 18.2 g of 1-methyl-2-(2-benzofuranyl)-pyridinium-iodide in 150 ml of methanol. Stirring is maintained for 1 hour at room temperature, and the light-yellow solution then poured into 1000 ml of water. The precipitating oil is extracted with chloroform; the chloroform extracts are dried over anhydrous sodium sulphate, and the solvent distilled off in vacuo. The oily residue is taken up in a little methylene chloride, and chromatographed through 150 g of aluminium oxide (2% water). The methylene chloride eluates yield after concentration by evaporation 13.2 g of 1-methyl-2-(2-benzofuranyl)-1,4,5,6-tetrahydropyridine in the form of light-yellow oil. This is dissolved in 130 ml of ethyl acetate and, after the addition of 1 g of palladium-charcoal catalyst (10%), hydrogenated at room temperature. After absorption of 935 ml of hydrogen in the course of 19 hours, hydrogenation ceases. The catalyst is filtered off, the filtrate concentrated in vacuo, and the residue distilled in high vacuum to obtain 1-methyl-2-(2-benzofuranyl)-piperidine as colourless oil, B.P. 93°-97° (0.02 Torr). The hydrochloride is obtained as colourless crystals, M.P. 188°-189°, by dissolving the distilled base in the fivefold amount of acetone, and neutralising the solution with a 2N solution of hydrogen chloride in ethyl acetate.

Workup

  1. additionis added dropwise in the course of 30 minutes
  2. stirringStirring
  3. extractionThe precipitating oil is extracted with chloroform
  4. dry with materialthe chloroform extracts are dried over anhydrous sodium sulphate
  5. distillationthe solvent distilled off in vacuo
  6. customchromatographed through 150 g of aluminium oxide (2% water)
  7. customThe methylene chloride eluates yield
  8. concentrationafter concentration
  9. customby evaporation 13.2 g of 1-methyl-2-(2-benzofuranyl)-1,4,5,6-tetrahydropyridine in the form of light-yellow oil
  10. dissolutionThis is dissolved in 130 ml of ethyl acetate
  11. additionafter the addition of 1 g of palladium-charcoal catalyst (10%)
  12. customhydrogenated at room temperature
  13. customAfter absorption of 935 ml of hydrogen in the course of 19 hours, hydrogenation ceases
  14. filtrationThe catalyst is filtered off
  15. concentrationthe filtrate concentrated in vacuo
  16. distillationthe residue distilled in high vacuum

Sources & evidence

ORD record
ord-6853bb38f86e4d96b3ba089ee690cc8f
Source dataset
uspto-grants-1986_07
Patent number
US04600719

Reaction notes

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