Hydrochloric Acid → 6-cyano-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one

HRID 2399303Notes

Reaction equation

HRID 2399303 reaction equation
Cl.N[C:3]1[CH:4]=[CH:5][C:6]2[O:11][C:10]([CH3:13])([CH3:12])[CH:9]([CH3:14])[C:8](=[O:15])[C:7]=2[CH:16]=1.N([O-])=O.[Na+].[C-:21]#[N:22].[K+]>C(O)C.O>[C:21]([C:3]1[CH:4]=[CH:5][C:6]2[O:11][C:10]([CH3:13])([CH3:12])[CH:9]([CH3:14])[C:8](=[O:15])[C:7]=2[CH:16]=1)#[N:22]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 9032Potassium CyanideHCID 19387214HCID 19387214, compoundHCID 23668193Sodium Nitrite

Product 1

HCID 157118796-cyano-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-oneYield 77%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent3×

Conditions

Temperature
90 °C

Procedure

A mixture of of 6-nitro-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one (23.5 g, 0.1 mol) and 10% palladium on carbon (2 g) in methanol was stirred under an atmosphere of hydrogen at 40°-50° C. for five hours at atmospheric pressure. The solution was then filtered, and the solvent removed from the filtrate under reduced pressure to give 21 g of 6-amino-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one as an oil. B. To a mixture of water (293 ml) and concentrated hydrochloric acid (25.7 ml) at 0° C. was added a solution of 6-amino-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one (20.5 g, 0.1 mol) in ethanol (140 ml). A solution of sodium nitrite (7.6 g, 0.11 mol) in water (90 ml) was then added, such that the temperature did not rise above 0° C. After fifteen minutes at 0° C., the reaction mixture was poured into a solution containing potassium cyanide (58.6 g, 0.90 mol) and cuprous cyanide (80.61 g, 0.90 mol) in water at 90° C., whilst maintaining the temperature of the reaction above 70° C. The resulting mixture was heated at 90° C. for one hour and then cooled to 20° C., extracted with ethyl acetate and the extract washed with water. The organic layer was separated and the solvent removed under reduced pressure. The residue was chromatographed on silica gel, eluting with dichloromethane/acetone (99/1) to give 16.58 g of 6-cyano-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one, 1H NMR (CDCl3): δ1.2 (d, 3H), 1.30 (s, 3H), 1.5 (s, 3H), 2.8 (q, 1H), 7.0 (d, 1H), 7.70 (d, 1H), 8.1 (s, 1H).

Workup

  1. customdid not rise above 0° C
  2. waitAfter fifteen minutes at 0° C.
  3. additionthe reaction mixture was poured into a solution
  4. temperaturewhilst maintaining
  5. customthe temperature of the reaction above 70° C
  6. temperaturecooled to 20° C.
  7. extractionextracted with ethyl acetate
  8. washthe extract washed with water
  9. customThe organic layer was separated
  10. customthe solvent removed under reduced pressure
  11. customThe residue was chromatographed on silica gel
  12. washeluting with dichloromethane/acetone (99/1)

Sources & evidence

ORD record
ord-9e63bfae7fa2415699155a7d6bd57f68
Source dataset
uspto-grants-1995_09
Patent number
US05447943

Reaction notes

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