Sulfuric Acid → Z-Asn(trt)-OH

HRID 1110187Notes

Reaction equation

HRID 1110187 reaction equation
[NH:1]([C:10]([O:12][CH2:13][C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)=[O:11])[C@H:2]([C:7]([OH:9])=[O:8])[CH2:3][C:4](=[O:6])[NH2:5].[C:20]1([C:26]([C:34]2[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=2)([C:28]2[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=2)O)[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1.C(OC(=O)C)(=O)C.S(=O)(=O)(O)O>C(O)(=O)C>[NH:1]([C:10]([O:12][CH2:13][C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1)=[O:11])[C@H:2]([C:7]([OH:9])=[O:8])[CH2:3][C:4](=[O:6])[NH:5][C:26]([C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1)([C:34]1[CH:35]=[CH:36][CH:37]=[CH:38][CH:39]=1)[C:28]1[CH:29]=[CH:30][CH:31]=[CH:32][CH:33]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 6457TriphenylcarbinolHCID 7918Acetic AnhydrideHCID 75314Benzyloxycarbonyl-asparagine

Product 1

HCID 15138256Z-Asn(trt)-OH

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of 13.3 g of Z-Asn-OH (50 mmol), 26 g of triphenylmethanol (100 mmol), 150 ml of acetic acid and 9.5 ml (100 mmol) of acetic anhydride is stirred at 50° for 15 minutes. Addition of 0.25 ml of conc. sulfuric acid produces, after 5 minutes, a clear yellow solution. After 11/2 hours, it is cooled and poured into 1.5 liters of ice-water. The precipitate is filtered off, thoroughly washed with water and dissolved in about 500 ml of ethyl acetate. The organic phase is washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated under reduced pressure to 250 g. Z-Asn(Trt)-OH is induced to crystallize by addition of 125 ml of hexane, m.p. 195°-196°.

Workup

  1. customproduces, after 5 minutes
  2. temperatureAfter 11/2 hours, it is cooled
  3. filtrationThe precipitate is filtered off
  4. washthoroughly washed with water
  5. dissolutiondissolved in about 500 ml of ethyl acetate
  6. washThe organic phase is washed with a saturated aqueous sodium chloride solution
  7. dry with materialdried over sodium sulfate
  8. concentrationconcentrated under reduced pressure to 250 g
  9. customto crystallize by addition of 125 ml of hexane, m.p. 195°-196°

Sources & evidence

ORD record
ord-44409ef531d944e5aa7a65cea830166b
Source dataset
uspto-grants-1994_06
Patent number
US05324833

Reaction notes

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