Pyridine → (S)-2-trityloxypropionic acid

HRID 1377847Notes

Reaction equation

HRID 1377847 reaction equation
C([O:3][C:4](=[O:8])[C@@H:5]([OH:7])[CH3:6])C.N1C=CC=CC=1.[C:15]1([C:21]([C:29]2[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=2)([C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=2)Cl)[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1>CN(C)C1C=CN=CC=1.C(#N)C>[C:21]([O:7][C@@H:5]([CH3:6])[C:4]([OH:3])=[O:8])([C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1)([C:29]1[CH:30]=[CH:31][CH:32]=[CH:33][CH:34]=1)[C:23]1[CH:24]=[CH:25][CH:26]=[CH:27][CH:28]=1

Participants

6

Reactant 3

HCID 1049PyridineHCID 6456Trityl chlorideHCID 92831(L)-ethyl lactate

Product 1

HCID 54161083(S)-2-trityloxypropionic acidYield 51.6%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 6342AcetonitrileSolvent

Procedure

To a solution of 38.6 g of (S)-2-hydroxy-propionic acid ethyl ester, 8.21 g of 4-dimethylamino-pyridine and 25.9 g of pyridine in 97 g of acetonitrile were added 92.0 g of triphenylchloromethane, and the mixture was heated at reflux for 16 h. The reaction mixture was cooled and partitioned between ethyl acetate and water. The organic layer was successively washed with 1M potassium hydrogensulfate solution, saturated potassium bicarbonate solution and brine, dried over magnesium sulfate and evaporated in vacuo. The residual oil was taken up in a solution of 22 g of sodium hydroxide in 200 ml of methanol, and the mixture was stirred for 16 h. The reaction mixture was filtered and the filtrate was diluted with 0.5 l of water. The resulting mixture was first concentrated in vacuo to a volume of about 0.5 l and then extracted with tert-butyl methyl ether and the organic phase was discarded. The pH of the aqueous phase was adjusted to 3 by the addition of 2N potassium hydrogensulfate solution and again extracted with tert-butyl methyl ether. The organic phase was washed with brine and dried over magnesium sulfate. The solvent was evaporated in vacuo and the residual oil was taken up in hexane to afford 56.0 g of (S)-2-trityloxy-propionic acid as off white crystals, m.p. 100°-106° C. Recrystallization from hexane/tert-butyl methyl ether afforded white crystals, m.p. 117.5°-119° C.

Workup

  1. temperaturethe mixture was heated
  2. temperatureat reflux for 16 h
  3. temperatureThe reaction mixture was cooled
  4. custompartitioned between ethyl acetate and water
  5. washThe organic layer was successively washed with 1M potassium hydrogensulfate solution, saturated potassium bicarbonate solution and brine
  6. dry with materialdried over magnesium sulfate
  7. customevaporated in vacuo
  8. filtrationThe reaction mixture was filtered
  9. additionthe filtrate was diluted with 0.5 l of water
  10. concentrationThe resulting mixture was first concentrated in vacuo to a volume of about 0.5 l
  11. extractionextracted with tert-butyl methyl ether
  12. additionThe pH of the aqueous phase was adjusted to 3 by the addition of 2N potassium hydrogensulfate solution
  13. extractionagain extracted with tert-butyl methyl ether
  14. washThe organic phase was washed with brine
  15. dry with materialdried over magnesium sulfate
  16. customThe solvent was evaporated in vacuo

Sources & evidence

ORD record
ord-22fe8c72a83a4143960c44a0649808ec
Source dataset
uspto-grants-1997_09
Patent number
US05665746

Reaction notes

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