Reaction #61854

Reaction equation

trifluoro-methanesulfonic acid 2-tert-butoxycarbonylamino-5-methyl-oxazol-4-yl ester

1-naphthaleneboronic acid

potassium acetate

→

5-methyl-4-naphthalen-1-yl-oxazol-2-ylamine

Yield 14.0%

5-Methyl-4-naphthalen-1-yl-oxazol-2-ylamine

Yield 14.0%

Solvents

1,4-dioxane

Conditions

Workup

1. 1
   OtherThe solvent was removed under reduced pressure and to the resulting yellow oil
2. 2
   workup.ADDITIONwas added dichloromethane (18 mL) and trifluoroacetic acid (2 mL)
3. 3
   Otherthe solvent was removed under reduced pressure
4. 4
   workup.ADDITIONthe resulting oil was diluted with ethyl acetate
5. 5
   Washwashed with a saturated solution of sodium hydrogen carbonate, brine
6. 6
   Dryingdried over magnesium sulfate
7. 7
   Filtrationfiltered
8. 8
   Otherthe solvent removed under reduced pressure
9. 9
   Otherto afford a brown oil
10. 10
    OtherPurification by column chromatography

Procedure

A mixture of trifluoro-methanesulfonic acid 2-tert-butoxycarbonylamino-5-methyl-oxazol-4-yl ester (100 mg), 1-naphthaleneboronic acid (61 mg) palladium (0) tetrakis(triphenylphosphine) (17 mg), potassium acetate (85 mg) and 1,4-dioxane (5 mL) was heated at 180° C. for 24 hours. The solvent was removed under reduced pressure and to the resulting yellow oil was added dichloromethane (18 mL) and trifluoroacetic acid (2 mL). The mixture was stirred at room temperature for 1 hour and then the solvent was removed under reduced pressure, the resulting oil was diluted with ethyl acetate and washed with a saturated solution of sodium hydrogen carbonate, brine, dried over magnesium sulfate, filtered and the solvent removed under reduced pressure to afford a brown oil. Purification by column chromatography afforded 5-methyl-4-naphthalen-1-yl-oxazol-2-ylamine (30) (9 mg, 14%) as a white solid. 1H NMR (DMSO-D6): 2.15 (3H, s), 6.5 (2H, br s), 7.4-7.5 (4H, m), 7.85-7.90 (2H, m), 8.2 (1H, m). Mass Spectrum (m/z): 225 (M+H)+.

Source