Ethanol → Ethyl 2-(2-thioxo-2,3-dihydrobenzoxazol-5-yl)propionate

HRID 866557Notes

Reaction equation

HRID 866557 reaction equation
COC1C=CC(NC2OC3C=C(C(C)C#N)C=CC=3N=2)=CC=1.[NH2:23][C:24]1[CH:25]=[C:26]([CH:31]([CH3:37])[C:32]([O:34][CH2:35][CH3:36])=[O:33])[CH:27]=[CH:28][C:29]=1[OH:30].C(O[C:41]([S-])=[S:42])C.[K+].C(O)C>O>[S:42]=[C:41]1[NH:23][C:24]2[CH:25]=[C:26]([CH:31]([CH3:37])[C:32]([O:34][CH2:35][CH3:36])=[O:33])[CH:27]=[CH:28][C:29]=2[O:30]1

Participants

6

Reactant 4

HCID 702EthanolHCID 2735045Potassium ethylxanthateHCID 12202638Ethyl 3-amino-4-hydroxy-phenyl-propionateHCID 203195952-[2-(4-Methoxyanilino)-6-benzoxazolyl]propionitrile

Product 1

HCID 20319623Ethyl 2-(2-thioxo-2,3-dihydrobenzoxazol-5-yl)propionate

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

2-[2-(4-methoxyanilino)-6-benzoxazolyl]propionitrile (i) A stirred mixture of ethyl 2-(3-amino-4-hydroxyphenyl)propionate (8.4 g.), potassium ethylxanthate (6.33 g.), ethanol (38 ml.) and water (6.5 ml.) was heated under reflux for 4 hours. The solution was evaporated to half volume and diluted with water (65 ml.). The mixture was acidified with 2N-hydrochloric acid and extracted several times with ether. The ethereal solution was washed with water, then dried with anhydrous sodium sulphate, and evaporated to give ethyl 2-(2-thioxo-2,3-dihydrobenzoxazol-5-yl)propionate as an oil. Dry chlorine was passed into a solution of the thione (9 g.) in freshly dried and distilled chloroform (150 ml.) with stirring for 4 hours. The solution was then washed with water, N-sodium hydroxide solution, then water (3x). The dried (Na2SO4) organic solution was evaporated to yield ethyl 2-(2-chloro-5-benzoxazolyl]propionate as a brown oil which was shown to be a single compound by thin layer chromatography. (j) A mixture of the 2-chloro compound (12.5 g.) of Example 3 (i) and p-chloroaniline (25 g.) was heated on a steam bath for one hour. The reaction mixture was dissolved in chloroform and the solution was washed with 2N hydrochloric acid (2x), water, 2N sodium hydroxide solution (2x) and water (3x). The chloroform solution was stirred with charcoal and anhydrous sodium sulphate, then filtered and evaporated. The residue was purified using prep t.l.c. plates to give ethyl-2-[2-(4-chloroanilino) -5-benzoxazolyl]propionate, mpt 135°-7° C., which was characterised by ir uv and nmr spectroscopy and by micro analysis which gave C 62.45% H 5.11% N 7.97% C18H17ClN3O2 requires C 62.70% H 4.93% N 8.13%

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 4 hours
  3. customThe solution was evaporated to half volume
  4. additiondiluted with water (65 ml.)
  5. extractionextracted several times with ether
  6. washThe ethereal solution was washed with water
  7. dry with materialdried with anhydrous sodium sulphate
  8. customevaporated

Sources & evidence

ORD record
ord-c4cf6983508b4388814b31e99eac6323
Source dataset
uspto-grants-1978_07
Patent number
US04100168

Reaction notes

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