Sulfuric Acid → 3,4-Dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-carbonitrile

HRID 268425Notes

Reaction equation

HRID 268425 reaction equation
[C:1]([C:3]([OH:21])([CH2:5][CH2:6][C:7]1[C:12]([CH3:13])=[C:11]([O:14]C(=O)C)[C:10]([CH3:18])=[C:9]([CH3:19])[C:8]=1O)[CH3:4])#[N:2].S(=O)(=O)(O)O>CO>[C:1]([C:3]1([CH3:4])[CH2:5][CH2:6][C:7]2[C:8](=[C:9]([CH3:19])[C:10]([CH3:18])=[C:11]([OH:14])[C:12]=2[CH3:13])[O:21]1)#[N:2]

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 21432304Rac. 2-cyano-4-(5-acetoxy-2-hydroxy-3,4,6,-trimethylphenyl)-butan-2-ol

Product 1

HCID 116802373,4-Dihydro-6-hydroxy-2,5,7,8-tetramethyl-2H-1-benzopyran-2-carbonitrile

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A solution of 5.31 g. of (±)-2-cyano-4-(5-acetoxy-2-hydroxy-3,4,6-trimethylphenyl)butan-2-ol in 60 ml. of methanol was cooled in an ice bath under N2. Sulfuric acid (3.8 ml.) was added over 5 minutes. The light yellow solution was stirred at 23° for 72 hours and then at reflux for 5 hours, cooled, poured into ice-H2O and filtered. The solid was washed with H2O and crystallized from ether-30°-60° petroleum ether to give (±)-2-cyano-6-hydroxy-2,5,7,8-tetramethylchroman as a white needle, m.p. 152.5°-153°.

Workup

  1. temperatureat reflux for 5 hours
  2. temperaturecooled
  3. filtrationfiltered
  4. washThe solid was washed with H2O
  5. customcrystallized from ether-30°-60° petroleum ether

Sources & evidence

ORD record
ord-129ce38bae3a40689a4aeeb9195d1837
Source dataset
uspto-grants-1976_03
Patent number
US03947473

Reaction notes

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