Triethylamine → 3-(4-Nitro-phenyl)-isoxazole-5-carboxylic acid ethyl ester

HRID 75759

Reaction equation

HRID 75759 reaction equation
[OH:1][N:2]=[C:3](Cl)[C:4]1[CH:9]=[CH:8][C:7]([N+:10]([O-:12])=[O:11])=[CH:6][CH:5]=1.[C:14]([O:18][CH2:19][CH3:20])(=[O:17])[C:15]#[CH:16].CCN(CC)CC>C1(C)C=CC=CC=1.CCOC(C)=O>[CH2:19]([O:18][C:14]([C:15]1[O:1][N:2]=[C:3]([C:4]2[CH:9]=[CH:8][C:7]([N+:10]([O-:12])=[O:11])=[CH:6][CH:5]=2)[CH:16]=1)=[O:17])[CH3:20]

Participants

6

Reactant 3

HCID 8471TriethylamineHCID 12182Ethyl propiolateHCID 915274alpha-Chloro-4-nitrobenzaldoxime

Product 1

HCID 9493753-(4-Nitro-phenyl)-isoxazole-5-carboxylic acid ethyl esterYield 51.7%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
80 °C

Procedure

To a solution of N-hydroxy-4-nitro-benzimidoyl chloride (2.0 g; 10 mmol) and ethyl propiolate (2.02 ml; 20 mmol) in toluene (25 ml) was added Et3N (1.46 ml; 10.5 mmol) drop wise for 10 minutes. The resulting reaction mixture was heated at 80° C. for 2.5 hours, and then diluted with EtOAc (50 ml) and transferred in a separating funnel. The EtOAc layer was washed with 0.1N HCl (10 ml) followed by water (3×10 ml) and brine (10 ml). The EtOAc layer was dried over anhydrous Na2SO4, solvent was evaporated and the residue was crystallized from CHCl3 and light petroleum to afford the title compound of step 1 (1.35 g; 51.7%). Mass (ES+), 263 (M++1); 1H NMR (CDCl3) δ: 1.45 (t, 3H), 4.48 (q, 2H), 7.26 (s, 1H), 8.02 (d, 2H), 8.35 (d, 2H).

Workup

  1. customThe resulting reaction mixture
  2. customtransferred in a separating funnel
  3. washThe EtOAc layer was washed with 0.1N HCl (10 ml)
  4. dry with materialThe EtOAc layer was dried over anhydrous Na2SO4, solvent
  5. customwas evaporated
  6. customthe residue was crystallized from CHCl3 and light petroleum

Sources & evidence

ORD record
ord-4057b49b7fde4dd7b211e637d8014c1a
Source dataset
uspto-grants-2014_09
Patent number
US08835428B2

Linked notes

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