Acetic Anhydride → rac-6-Acetyloxy-3,4-dihydro-2,5,7,8-tetramethyl-2-(phenyl-ethynyl)-2H-1-benzopyran

HRID 256866Notes

Reaction equation

HRID 256866 reaction equation
[CH3:1][C:2]1([C:16]#[C:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[CH2:7][CH2:6][C:5]2[C:8]([CH3:15])=[C:9]([OH:14])[C:10]([CH3:13])=[C:11]([CH3:12])[C:4]=2[O:3]1.[C:24](OC(=O)C)(=[O:26])[CH3:25]>N1C=CC=CC=1>[C:24]([O:14][C:9]1[C:10]([CH3:13])=[C:11]([CH3:12])[C:4]2[O:3][C:2]([CH3:1])([C:16]#[C:17][C:18]3[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=3)[CH2:7][CH2:6][C:5]=2[C:8]=1[CH3:15])(=[O:26])[CH3:25]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 151718093,4-dihydro-2,5,7,8-tetramethyl-2-(2-phenylethynyl)-2H-1-benzopyran-6-ol

Product 1

HCID 15171916rac-6-Acetyloxy-3,4-dihydro-2,5,7,8-tetramethyl-2-(phenyl-ethynyl)-2H-1-benzopyran

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

A mixture of 0.3 g of rac-3,4-dihydro-2,5,7,8-tetramethyl-2-(phenylethynyl)-2H-1-benzopyran-6-ol, 7 ml of pyridine and 0.5 ml of acetic anhydride was allowed to sit at room temperature over night. The reagents were evaporated under reduced pressure, at the end azeotropically with toluene. The residue was crystallized from hexane to give 0.21 g of colorless crystals with m.p. 123°-125°.

Workup

  1. waitto sit at room temperature over night
  2. customThe reagents were evaporated under reduced pressure, at the end azeotropically with toluene
  3. customThe residue was crystallized from hexane

Sources & evidence

ORD record
ord-24a8a6f034124ce9b2dc7efbf918a59f
Source dataset
uspto-grants-1993_11
Patent number
US05260294

Reaction notes

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