Water → 5,7-Dimethylchroman-2-one

HRID 1761656

Reaction equation

HRID 1761656 reaction equation
C[C:2]([C:4]1[CH:13]=[CH:12][C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[C:5]=1O)=O.C12CC3CC(CC(C3)C1=[O:25])C2.N1CCCC1.[OH2:31]>C1(C)C=CC=CC=1>[CH3:7][C:6]1[CH:5]=[C:4]([CH3:2])[CH:13]=[C:12]2[C:11]=1[CH2:10][CH2:9][C:8](=[O:25])[O:31]2

Participants

6

Reactant 4

HCID 962WaterHCID 31268PyrrolidineHCID 64151AdamantanoneHCID 697331'-Hydroxy-2'-acetonaphthone

Product 1

HCID 126604295,7-Dimethylchroman-2-one

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A mixture of 1-hydroxy-2-acetonaphthone (10.1 g), (1A), adamantanone (9 g) and pyrrolidine (10 cm3) in toluene (300 cm3) was boiled (10 hours) and water separated. The yellow reaction mixture turned first crimson and then dark brown. Toluene was removed under reduced pressure and the residual enamine crystallised from acetone as discoloured crystals (8 g). The enamine (2) (10 g) was treated with conc. hydrochloric acid (1 cm3) in methanol (200 cm3). The crimson solution was evaporated and the residual dark oil crystallised from acetone, yielding the chromanone (3) (8.4 g) as yellow needles. The chromanone (0.5 g) was reduced by sodium borohydride (0.5 g) in methanol to yield the chromanol (4) (0.32 g) which was heated with anhydrous copper sulphate to give HC7 (formula (5) R=H) (0.28 g) as a discoloured solid which was decolourised with activated charcoal and recrystallised from acetone.

Workup

  1. customseparated
  2. customToluene was removed under reduced pressure
  3. customthe residual enamine crystallised from acetone as discoloured crystals (8 g)
  4. additionThe enamine (2) (10 g) was treated with conc. hydrochloric acid (1 cm3) in methanol (200 cm3)
  5. customThe crimson solution was evaporated
  6. customthe residual dark oil crystallised from acetone

Sources & evidence

ORD record
ord-9727f45321f34d7bb00e7446f2686b27
Source dataset
uspto-grants-1989_05
Patent number
US04826977

Linked notes

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