Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → (4S,5R)-N-Carbobenzyloxy-2-(2,4-dimethoxyphenyl)-4-phenyl-5-oxazolidinecarboxylic acid methyl ester

HRID 1072943Notes

Reaction equation

HRID 1072943 reaction equation
[CH3:1][O:2][C:3](=[O:24])[CH:4]([OH:23])[CH:5]([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)[NH:6][C:7]([O:9][CH2:10][C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)=[O:8].COC(=O)[C@H](O)[C@H](C1C=CC=CC=1)NC(OCC1C=CC=CC=1)=O.CO[CH:51](OC)[C:52]1[CH:57]=[CH:56][C:55]([O:58][CH3:59])=[CH:54][C:53]=1[O:60][CH3:61].C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1>C1COCC1>[CH3:1][O:2][C:3]([C@@H:4]1[O:23][CH:51]([C:52]2[CH:57]=[CH:56][C:55]([O:58][CH3:59])=[CH:54][C:53]=2[O:60][CH3:61])[N:6]([C:7]([O:9][CH2:10][C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=2)=[O:8])[C@H:5]1[C:17]1[CH:18]=[CH:19][CH:20]=[CH:21][CH:22]=1)=[O:24]

Participants

6

Reactant 4

HCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)HCID 142873251-(Dimethoxymethyl)-2,4-dimethoxybenzeneHCID 22389496N-Carbobenzyloxy-beta-phenyl isoserine methyl esterHCID 22865499(2R,3S)-N-carbobenzyloxy-beta-phenyl isoserine methyl ester

Product 1

HCID 57035355(4S,5R)-N-Carbobenzyloxy-2-(2,4-dimethoxyphenyl)-4-phenyl-5-oxazolidinecarboxylic acid methyl ester

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

N-Carbobenzyloxy-β-phenyl isoserine methyl ester (Preparation No. 19, 3C, 0.375 g, 1.14 mM) is dissolved in dry THF (10 mL) and the solution treated with 2,4-dimethoxy benzaldehyde dimethyl acetal (4, 0.300 g, 1.42 mM) and pyridinium p-toluenesulfonate (10 mg) and the solution heated to distill off the THF and methanol. After ½ the THF is distilled off, THF (10 mL) is added and the reaction distilled to ½ volume again. The process is repeated three times. The reaction is then concentrated in vacuo and the residue chromatographed over 75 g silica gel packed and eluted in acetone-hexane (300 mL of 20-80 and 300 mL of 25-75). Fractions of 20 mL are collected and analyzed by TLC. The following fractions are combined and evaporated under vacuum.

Workup

  1. temperaturethe solution heated
  2. distillationto distill off the THF and methanol
  3. distillationis distilled off
  4. additionTHF (10 mL) is added
  5. distillationthe reaction distilled
  6. concentrationThe reaction is then concentrated in vacuo
  7. customthe residue chromatographed over 75 g silica gel
  8. washeluted in acetone-hexane (300 mL of 20-80 and 300 mL of 25-75)
  9. customFractions of 20 mL are collected
  10. customevaporated under vacuum

Sources & evidence

ORD record
ord-f7b7d1a0e4cd4bbc9fab5868e6e61bbe
Source dataset
uspto-grants-2005_06
Patent number
US06911549B1

Reaction notes

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