Sulfuric Acid → 7-Isopropyl-2,4-dimethyl-benzooxazol-6-ol

HRID 38443

Reaction equation

HRID 38443 reaction equation
[NH2:1][C:2]1[C:7]([CH3:8])=[CH:6][C:5]([OH:9])=[C:4]([CH:10]([CH3:12])[CH3:11])[C:3]=1[OH:13].O[C:15]1C=C(C(C)C)C=C(O)[C:20]=1C.C1(C)CC(=O)C(C(C)C)C(=O)C1.C(OC(OCC)OCC)C.OS(O)(=O)=O>CO.[Cl-].[Ti+4].[Cl-].[Cl-].[Cl-]>[CH:10]([C:4]1[C:3]2[O:13][C:15]([CH3:20])=[N:1][C:2]=2[C:7]([CH3:8])=[CH:6][C:5]=1[OH:9])([CH3:11])[CH3:12]

Participants

8

Reactant 5

HCID 1118Sulfuric AcidHCID 31214Ethyl orthoformateHCID 119881382-Isopropyl-5-methylcyclohexane-1,3-dioneHCID 23345336CymorcinHCID 595987544-Amino-2-isopropyl-5-methyl-benzene-1,3-diol

Product 1

HCID 595986327-Isopropyl-2,4-dimethyl-benzooxazol-6-ol

Reagents, catalysts & solvents 2

HCID 160960Diamminetetrachlorotitanate(IV)CatalystHCID 887MethanolSolvent2×

Conditions

Temperature
0 °C

Procedure

To a flask charged with 4-amino-2-isopropyl-5-methyl-benzene-1,3-diol (250 mg, 1.4 mmol) (Treibs and Albrecht, “The dihydroxycymenes. IV. Isocymorcin (3,5-dihydroxycymene) from 3,5-menthanedione by dehydrogenation and total synthesis,” Journal fuer Praktische Chemie (1961), 13, 291-305), purged with argon, and cooled to 0° C., was sequentially added triethylorthoformate (0.53 mL, 4.2 mmol), MeOH (2.5 mL), and a 10% v/v solution of H2SO4 in MeOH (25 μL). The reaction was allowed to warm to room temperature slowly, stirred overnight, quenched with saturated NaHCO3, and concentrated. The residue was partitioned between water and methylene chloride. The combined organic phases were dried with Na2SO4 and concentrated. Purification via flash chromatography afforded 175 mg of 7-isopropyl-2,4-dimethyl-benzooxazol-6-ol.

Workup

  1. custompurged with argon
  2. temperatureto warm to room temperature slowly
  3. customquenched with saturated NaHCO3
  4. concentrationconcentrated
  5. customThe residue was partitioned between water and methylene chloride
  6. dry with materialThe combined organic phases were dried with Na2SO4
  7. concentrationconcentrated
  8. customPurification via flash chromatography

Sources & evidence

ORD record
ord-f48841bbb421402992e308f5406e6763
Source dataset
uspto-grants-2013_09
Patent number
US08524725B2

Linked notes

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