Reaction #1126405

Reaction equation

triethylamine

1,4-phenylenediisocyanate

1-ethynyl-2-methoxy-benzene

5-nitro-pentanoic acid methyl ester

→

yellow oil

Yield 112.6%

4-[5-(2-Methoxy-phenyl)-isoxazol-3-yl]-butyric acid methyl ester

Yield 112.6%

Solvents

toluene

Conditions

Workup

1. 1
   Temperatureto reflux under N2 overnight
2. 2
   FiltrationFilter mixture through a pad of Celite®
3. 3
   Washrinse with toluene
4. 4
   ConcentrationConcentrate

Procedure

Add 1,4-phenylenediisocyanate (19.22 g, 120.0 mmol) to a stirred solution of 1-ethynyl-2-methoxy-benzene (2204901, 5.29 g, 40.0 mmol) and 5-nitro-pentanoic acid methyl ester (7.91 g, 49.1 mmol) in toluene (300 mL, anhydrous) and stir under N2. Add triethylamine (16.7 mL, 120.0 mmol) and heat to reflux under N2 overnight. Filter mixture through a pad of Celite® and rinse with toluene. Concentrate to get 12.4 g yellow oil. Adsorb on SiO2 and purify the residue by flash chromatography on silica gel eluting with 0-30% EtOAc/hexanes to afford the title compound (14.0 g, 74%). MS (IS) 276 (M+1)+.

Source