Acetic Anhydride → Pirnabine

HRID 2072315Notes

Reaction equation

HRID 2072315 reaction equation
[OH:1][C:2]1[C:11]2[C:10]3[CH2:12][CH:13]([CH3:16])[CH2:14][CH2:15][C:9]=3[C:8]([CH3:18])([CH3:17])[O:7][C:6]=2[CH:5]=[C:4]([CH3:19])[CH:3]=1.[C:20](OC(=O)C)(=[O:22])[CH3:21]>N1C=CC=CC=1>[C:20]([O:1][C:2]1[C:11]2[C:10]3[CH2:12][CH:13]([CH3:16])[CH2:14][CH2:15][C:9]=3[C:8]([CH3:18])([CH3:17])[O:7][C:6]=2[CH:5]=[C:4]([CH3:19])[CH:3]=1)(=[O:22])[CH3:21]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 2931753,6,6,9-Tetramethyl-7,8,9,10-tetrahydro-6H-benzo[c]chromen-1-ol

Product 1

HCID 50137Pirnabine

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

A solution of 1-hydroxy-7,8,9,10-tetrahydro-3,6,6,9-tetramethyl-6H-dibenzo[ b,d]pyran (9.07 g., 0.035 mole) and acetic anhydride (7.1 g., 0.07 mole) in 25 ml. of pyridine was warmed over a steam bath for 2 hours. The reaction mixture was allowed to cool to room temperature and pyridine was removed by evaporation under reduced pressure. Water was added to the residue and the aqueous mixture was extracted with three portions of ether. The ethereal extracts were combined, washed with water, 6N HCl, again with water, dried over Na2SO4 and concentrated under reduced pressure to 9.5 g. (90%) of a colorless solid, m.p. 115°-119° C.

Workup

  1. custompyridine was removed by evaporation under reduced pressure
  2. additionWater was added to the residue
  3. extractionthe aqueous mixture was extracted with three portions of ether
  4. washwashed with water, 6N HCl, again with water
  5. dry with materialdried over Na2SO4
  6. concentrationconcentrated under reduced pressure to 9.5 g

Sources & evidence

ORD record
ord-7074f7d8502f449c91414f10aef2ee7f
Source dataset
uspto-grants-1977_09
Patent number
US04051152

Reaction notes

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