(5-Nitro-2-phenyl-benzoxazole4-yl)-acetonitrile → 2-Phenyl-6,8-dihydro-oxazolo[4,5-e]indol-7-one

HRID 1859057Notes

Reaction equation

HRID 1859057 reaction equation
[N+]([C:4]1[CH:5]=[CH:6][C:7]2[O:11][C:10]([C:12]3[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=3)=[N:9][C:8]=2[C:18]=1[CH2:19][C:20]#[N:21])([O-])=O.[OH:22]S(O)(=O)=O.O>O.C(O)(=O)C.[Zn]>[C:12]1([C:10]2[O:11][C:7]3[C:8]([N:9]=2)=[C:18]2[C:4](=[CH:5][CH:6]=3)[NH:21][C:20](=[O:22])[CH2:19]2)[CH:13]=[CH:14][CH:15]=[CH:16][CH:17]=1

Participants

6

Reactant 2

HCID 15252117(5-Nitro-2-phenyl-benzoxazole4-yl)-acetonitrile2×HCID 21910475Sulfuric acid hydrate (1:1)

Product 1

HCID 212534362-Phenyl-6,8-dihydro-oxazolo[4,5-e]indol-7-one

Reagents, catalysts & solvents 3

HCID 23994ZincCatalystHCID 176Acetic AcidSolventHCID 962WaterSolvent

Conditions

Temperature
100 °C

Procedure

A solution of (5-nitro-2-phenyl-benzoxazole4-yl)-acetonitrile (1.10 g, 3.98 mmol) (Starting Material 5) was suspended in concentrated H2SO4 /H2O (1/1, 25 mL) and stirred at 100° C. for 30 min. The resulting solution was diluted with water and extracted with ethyl acetate, and the combined organic extracts were dried over anhydrous magnesium sulfate and concentrated in vacuo to give the crude acid. To a solution of the crude acid in acetic acid (10 mL) heated at reflux was added excess zinc dust (1.57 g, 24.2 mmol) portionwise during thirty minutes or until the reaction solution clarified. The mixture was filtered through a Celite® (Fisher Scientific) pad and washed with hot DMF. The solvent was removed in vacuo and residue was suspended and stirred for 30 minutes in 3M hydrochloric acid. The insoluble solid material was collected, washed with water, and air dried to give 2-phenyl-6,8-dihydro-oxazolo[4,5-e]indol-7-one. (Yield 180 mg, 18%).

Workup

  1. extractionextracted with ethyl acetate
  2. dry with materialthe combined organic extracts were dried over anhydrous magnesium sulfate
  3. concentrationconcentrated in vacuo
  4. customto give the crude acid
  5. temperatureat reflux
  6. filtrationThe mixture was filtered through a Celite® (Fisher Scientific) pad
  7. washwashed with hot DMF
  8. customThe solvent was removed in vacuo and residue
  9. stirringstirred for 30 minutes in 3M hydrochloric acid
  10. customThe insoluble solid material was collected
  11. washwashed with water, and air
  12. customdried

Sources & evidence

ORD record
ord-7d601a6a0ceb4730a17e1ab75bdac1ba
Source dataset
uspto-grants-2000_11
Patent number
US06153634

Reaction notes

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