Sulfuric Acid → HCID 54238529, compound

HRID 975957Notes

Reaction equation

HRID 975957 reaction equation
S(=O)(=O)(O)O.[C:6]1([CH:12]2[NH:16][C@H:15]([C:17]([OH:19])=[O:18])[CH2:14][S:13]2)[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.[CH2:20]=[C:21]([CH3:23])[CH3:22].C(=O)(O)[O-].[Na+]>C(Cl)(Cl)Cl>[C:6]1([CH:12]2[NH:16][C@H:15]([C:17]([O:19][C:21]([CH3:23])([CH3:22])[CH3:20])=[O:18])[CH2:14][S:13]2)[CH:7]=[CH:8][CH:9]=[CH:10][CH:11]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 8255IsobutyleneHCID 516892Sodium BicarbonateHCID 11009168(4R)-2-phenyl-1,3-thiazolidine-4-carboxylic acid

Product 1

HCID 54238529HCID 54238529, compound

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Conditions

Temperature
5 °C

Procedure

C--tert-Butyl (2RS,4R)-2-phenyl-4-thiazolidinecarboxylate may be prepared as follows: 15 cm3 of concentrated sulphuric acid are added dropwise to a suspension of 53.7 g of (2RS,4R)-2-phenyl-4-thiazolidinecarboxylic acid in 590 cm3 of chloroform cooled to a temperature in the vicinity of 5° C. The reaction mixture is saturated with isobutene for 5 hours while stirring and while maintaining the temperature at 5° C. After returning to a temperature in the vicinity of 20° C., stirring is continued for 20 hours. The solution is brought to a pH of 8 by addition of a saturated aqueous sodium bicarbonate solution, then the aqueous phase is separated and extracted with 2 times 300 cm3 of chloroform. The combined organic phases are washed with 2 times 300 cm3 of water, dried over magnesium sulphate and concentrated to dryness under reduced pressure at 40° C. The oily residue obtained is purified by chromatography on silica [eluent: ethyl acetate/cyclohexane (20/80 by volume)]. The fractions containing the expected product are combined, then concentrated to dryness under reduced pressure. 42.8 g of tert-butyl (2RS,4R)-2-phenyl-4thiazolidinecarboxylate are thus obtained in the form of a pale yellow oil, a (40/60 by weight) mixture of the (2R,4R) and (2S,4R) isomers, used as it is in subsequent syntheses.

Workup

  1. temperaturewhile maintaining the temperature at 5° C
  2. customAfter returning to a temperature in the vicinity of 20° C.
  3. stirringstirring
  4. customthe aqueous phase is separated
  5. extractionextracted with 2 times 300 cm3 of chloroform
  6. washThe combined organic phases are washed with 2 times 300 cm3 of water
  7. dry with materialdried over magnesium sulphate
  8. concentrationconcentrated to dryness under reduced pressure at 40° C
  9. customThe oily residue obtained
  10. customis purified by chromatography on silica [eluent: ethyl acetate/cyclohexane (20/80 by volume)]
  11. additionThe fractions containing the expected product
  12. concentrationconcentrated to dryness under reduced pressure

Sources & evidence

ORD record
ord-7fde275fe9454a61b5ba43b8c263707d
Source dataset
uspto-grants-1997_03
Patent number
US05610144

Reaction notes

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