Water → 7-Methoxy-4-methyl-2H-1-benzopyran

HRID 236979Notes

Reaction equation

HRID 236979 reaction equation
O[C:2]1([CH3:14])[C:7]2[CH:8]=[CH:9][C:10]([O:12][CH3:13])=[CH:11][C:6]=2[O:5][CH2:4][CH2:3]1.P(Cl)(Cl)(Cl)=O.O>N1C=CC=CC=1>[CH3:13][O:12][C:10]1[CH:9]=[CH:8][C:7]2[C:2]([CH3:14])=[CH:3][CH2:4][O:5][C:6]=2[CH:11]=1

Participants

5

Reactant 3

HCID 962WaterHCID 24813Phosphorus oxychlorideHCID 203045882,3-Dihydro-4-hydroxy-7-methoxy-4-methyl-4H-1-benzopyran

Product 1

HCID 122094127-Methoxy-4-methyl-2H-1-benzopyran

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

The carbinol of step (a) (73.3 g) was stirred with phosphorus oxychloride (19.3 g; 11.6 ml) in dry pyridine (380 ml) for 20 hours under nitrogen. The reaction mixture was poured into water, extracted with ether and the ethereal extracts were washed with dilute acid, then sodium bicarbonate solution, then water and dried. Evaporation of the solvent left 58 g of residue (87.2%). MS evidence was correct for the required compound. NMR suggested that the product was in fact a mixture of isomeric alkenes.

Workup

  1. extractionextracted with ether
  2. washthe ethereal extracts were washed
  3. additionwith dilute acid
  4. dry with materialsodium bicarbonate solution, then water and dried
  5. customEvaporation of the solvent
  6. waitleft 58 g of residue (87.2%)
  7. additiona mixture of isomeric alkenes

Sources & evidence

ORD record
ord-9c2f445cdf7743dcb734cdd9167845de
Source dataset
uspto-grants-1979_06
Patent number
US04159273

Reaction notes

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