Triethylamine → 4,5-Dihydro-5-(3-hydroxyphenyl)-2-(2-thienyl)-1,3-oxazole

HRID 2119050Notes

Reaction equation

HRID 2119050 reaction equation
[CH:1]1[CH:6]=[C:5]([OH:7])[CH:4]=[C:3]([CH:8]([OH:11])[CH2:9][NH2:10])[CH:2]=1.Cl.Cl.[S:14]1[CH:18]=[CH:17][CH:16]=[C:15]1[C:19](=N)OCC.C(N(CC)CC)C>O1CCCC1.C(OCC)(=O)C.O>[OH:7][C:5]1[CH:4]=[C:3]([CH:8]2[O:11][C:19]([C:15]3[S:14][CH:18]=[CH:17][CH:16]=3)=[N:10][CH2:9]2)[CH:2]=[CH:1][CH:6]=1

Participants

7

Reactant 3

HCID 8471TriethylamineHCID 3016408Benzenemethanol, alpha-(aminomethyl)-3-hydroxy-, hydrochloride (1:1)HCID 12231044Ethyl thiophene-2-carboximidate hydrochloride

Product 1

HCID 139213704,5-Dihydro-5-(3-hydroxyphenyl)-2-(2-thienyl)-1,3-oxazoleYield 81.5%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Procedure

A mixture of (±) norphenylephrine hydrochloride (10 g, 0.05 mol), ethyl thiophene-2-imidate hydrochloride (10 g, 0.05 mol) and triethylamine (5 g, 0.05 mol) in tetrahydrofuran (300 ml) is heated to reflux for 8 hours. The mixture is dissolved in ethyl acetate and water. The aqueous layer is extracted twice with ethyl acetate. The combined ethyl acetate solutions are washed twice with dilute aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and concentrated to dryness to obtain a viscous, partly crystalline material (10 g). This material is triturated with ether to obtain crystals (5 g) of m.p. 150°. These crystals are dissolved in hot acetonitrile and the solution is filtered and allowed to cool. The crystals (3.4 g) are filtered off, washed with acetonitrile and dried in vacuo; m.p. 156°-158° C.

Workup

  1. temperatureis heated
  2. temperatureto reflux for 8 hours
  3. extractionThe aqueous layer is extracted twice with ethyl acetate
  4. washThe combined ethyl acetate solutions are washed twice with dilute aqueous sodium chloride solution
  5. dry with materialdried over anhydrous magnesium sulfate
  6. concentrationconcentrated to dryness

Sources & evidence

ORD record
ord-c34648ca46254b91984891f318c9e8a7
Source dataset
uspto-grants-1987_07
Patent number
US04681940

Reaction notes

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