6-nitro-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one → HCID 19387214, compound

HRID 1655369Notes

Reaction equation

HRID 1655369 reaction equation
[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[O:12][C:11]([CH3:14])([CH3:13])[CH:10]([CH3:15])[C:9](=[O:16])[C:8]=2[CH:17]=1)([O-])=O>[Pd].CO>[NH2:1][C:4]1[CH:5]=[CH:6][C:7]2[O:12][C:11]([CH3:14])([CH3:13])[CH:10]([CH3:15])[C:9](=[O:16])[C:8]=2[CH:17]=1

Participants

4

Reactant 1

HCID 193871946-nitro-2,2,3-trimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 19387214HCID 19387214, compoundYield 102.3%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 887MethanolSolvent

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): δ 1.2 (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. filtrationThe solution was then filtered
  2. customthe solvent removed from the filtrate under reduced pressure

Sources & evidence

ORD record
ord-0d83da7888974e9683b6fc48bc28be1d
Source dataset
uspto-grants-1993_10
Patent number
US05250547

Reaction notes

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