Sodium Carbonate → N-(3,4-dichlorobenzoyl)proline

HRID 569789Notes

Reaction equation

HRID 569789 reaction equation
[NH:1]1[CH2:8][CH2:7][CH2:6][C@H:2]1[C:3]([OH:5])=[O:4].C([O-])([O-])=O.[Na+].[Na+].[OH-].[Na+].CC1C(C2(C3C(C)=CC(O)=C(C(C)C)C=3)OC(=O)C3C2=CC=CC=3)=CC(C(C)C)=C(O)C=1.[Cl:49][C:50]1[CH:51]=[C:52]([CH:56]=[CH:57][C:58]=1[Cl:59])[C:53](Cl)=[O:54]>O.CCOCC.CC1C(C2(C3C(C)=CC(O)=C(C(C)C)C=3)OC(=O)C3C2=CC=CC=3)=CC(C(C)C)=C(O)C=1>[Cl:49][C:50]1[CH:51]=[C:52]([CH:56]=[CH:57][C:58]=1[Cl:59])[C:53]([N:1]1[CH2:8][CH2:7][CH2:6][C@H:2]1[C:3]([OH:5])=[O:4])=[O:54]

Participants

9

Reactant 5

HCID 10340Sodium CarbonateHCID 14798Sodium Hydroxide2×HCID 31316ThymolphthaleinHCID 76403Benzoyl chloride, 3,4-dichloro-HCID 145742L-Proline

Product 1

HCID 822734N-(3,4-dichlorobenzoyl)prolineYield 81%

Reagents, catalysts & solvents 3

HCID 31316ThymolphthaleinCatalystHCID 962WaterSolventHCID 3283Diethyl EtherSolvent

Conditions

Temperature
10 °C

Procedure

A solution of L-proline (30 g, 0.26 mol), thymolphthalein (5 mg), and Na2CO3 (100 g) in water (500 mL) was treated at room temperature with concentrated aqueous NaOH solution until the solution was blue to the thymolphthalein indicator. The stirred solution was cooled to about 10° C. and treated portionwise with a solution of 3,4-dichlorobenzoyl chloride (58.65 g, 0.28 mol) in ether (100 mL) with periodic addition of concentrated aqueous NaOH solution as necessary to maintain the blue color. The reaction mixture was stirred for an additional 10 min after the addition was completed and then extracted with ether (2×150 mL). The aqueous phase was acidified to pH 1 with concentrated HC1 and extracted with ethyl acetate (4×250 mL). The combined ethyl acetate solution was washed with brine (150 mL), dried (Na2SO4), and concentrated in vacuo. The solid residue was crystallized from hot ethyl acetate-petroleum ether (2:1, 300 mL) to give 60.5 g (81%) of N-(3,4-dichlorobenzoyl)proline as fine white prisms. Recrystallization from the same solvents afforded the analytical sample of N-(3,4-dichlorobenzoyl)proline.

Workup

  1. temperatureto maintain the blue color
  2. additionafter the addition
  3. extractionextracted with ether (2×150 mL)
  4. extractionextracted with ethyl acetate (4×250 mL)
  5. washThe combined ethyl acetate solution was washed with brine (150 mL)
  6. dry with materialdried (Na2SO4)
  7. concentrationconcentrated in vacuo
  8. customThe solid residue was crystallized from hot ethyl acetate-petroleum ether (2:1, 300 mL)

Sources & evidence

ORD record
ord-29161c79ab4443acbd1e94cb2fcfe374
Source dataset
uspto-grants-1988_03
Patent number
US04734423

Reaction notes

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