p-Toluenesulfonic acid → 3-Benzyl 4-ethyl 4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylate

HRID 579504Notes

Reaction equation

HRID 579504 reaction equation
[CH2:1]([O:8][C:9]([NH:11][C:12]([CH2:22][OH:23])([CH2:18][CH2:19][CH:20]=[CH2:21])[C:13]([O:15][CH2:16][CH3:17])=[O:14])=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.CO[C:26](OC)([CH3:28])[CH3:27].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[CH2:18]([C:12]1([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH2:22][O:23][C:26]([CH3:28])([CH3:27])[N:11]1[C:9]([O:8][CH2:1][C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1)=[O:10])[CH2:19][CH:20]=[CH2:21]

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 64952,2-DimethoxypropaneHCID 66833560Ethyl 2-(benzyloxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate

Product 1

HCID 668328333-Benzyl 4-ethyl 4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylateYield 57%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of the ethyl 2-(benzyloxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate 4 (820 mg, 2.55 mmol) in toluene (10 mL) was treated with 2,2-dimethoxy propane (2 mL) and 4-toluenesulfonic acid (100 mg). The mixture was heated under reflux for 1 h, cooled, concentrated and purified using a combiflash system (12 g silica gel column, eluting with 5-50% of ethyl acetate in heptanes) to give 3-benzyl 4-ethyl 4-(but-3-enyl)-2,2-dimethyloxazolidine-3,4-dicarboxylate (530 mg, 57%). 1H NMR (CDCl3) δ 7.36 (m, 5H), 5.75 (m, 1H), 4.51 (m, 4H), 4.06 (m, 4H) 2.08 (m, 4H), 1.65 (2 s, 6H), 1.13 (t, J=7.1 Hz, 3H). MS found for C20H27NO5 m/z [332 (M+1)].

Workup

  1. temperatureThe mixture was heated
  2. temperatureunder reflux for 1 h
  3. temperaturecooled
  4. concentrationconcentrated
  5. custompurified
  6. washa combiflash system (12 g silica gel column, eluting with 5-50% of ethyl acetate in heptanes)

Sources & evidence

ORD record
ord-d50915c38630403680f56ef24c7c16f4
Source dataset
uspto-grants-2015_05
Patent number
US09040703B2

Reaction notes

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