Pyridine → 4-(2-pyridyl)-2H-1-benzopyran

HRID 1073890Notes

Reaction equation

HRID 1073890 reaction equation
C[C:2]1(C)[CH2:7][CH:6]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N:9]=2)[C:5]2[CH:14]=[CH:15][CH:16]=[CH:17][C:4]=2[O:3]1.N1C=CC=CC=1.BrBr>C(Cl)(Cl)(Cl)Cl>[N:9]1[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=1[C:6]1[C:5]2[CH:14]=[CH:15][CH:16]=[CH:17][C:4]=2[O:3][CH2:2][CH:7]=1

Participants

5

Reactant 3

HCID 1049PyridineHCID 24408BromineHCID 198956113,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran

Product 1

HCID 1317167174-(2-pyridyl)-2H-1-benzopyran

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

0.5 g of 3,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran was dissolved in 10 ml of carbon tetrachloride at room temperature and 0.25 ml of pyridine and 0.12 ml of bromine were added. The mixture was stirred at room temperature for 1 hour, then at 35° C. for 1 hour and finally at 65° C. for 1 hour. After cooling the mixture was washed with sodium bicarbonate solution, the aqueous washings were extracted with dichloromethane and the combined organic phases were washed with water, dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using 2% (v/v) methanol/dichloromethane for the elution. The product was recrystallized from t-butyl methyl ether to give 230 mg of 6-bromo-3,4-dihydro-2,2-dimethyl)-4-(2-pyridyl)-2H-1-benzopyran of melting point 134-136° C.

Workup

  1. waitat 35° C. for 1 hour
  2. waitfinally at 65° C. for 1 hour
  3. temperatureAfter cooling the mixture
  4. washwas washed with sodium bicarbonate solution
  5. extractionthe aqueous washings were extracted with dichloromethane
  6. washthe combined organic phases were washed with water
  7. dry with materialdried over sodium sulphate
  8. customevaporated
  9. customThe residue was chromatographed on silica gel using 2% (v/v) methanol/dichloromethane for the elution
  10. customThe product was recrystallized from t-butyl methyl ether

Sources & evidence

ORD record
ord-5c85f3d2a6d24717a2d275d681704357
Source dataset
uspto-grants-1990_11
Patent number
US04971982

Reaction notes

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