Imidazole → Benzyl (S)-2-(Boc-amino)-4-iodobutanoate

HRID 226218Notes

Reaction equation

HRID 226218 reaction equation
C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N1C=CN=C1.[I:25]I.[CH2:27]([O:34][C:35](=[O:48])[CH:36]([NH:40][C:41]([O:43][C:44]([CH3:47])([CH3:46])[CH3:45])=[O:42])[CH2:37][CH2:38]O)[C:28]1[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=1>C(Cl)Cl>[CH2:27]([O:34][C:35](=[O:48])[CH:36]([NH:40][C:41]([O:43][C:44]([CH3:47])([CH3:46])[CH3:45])=[O:42])[CH2:37][CH2:38][I:25])[C:28]1[CH:33]=[CH:32][CH:31]=[CH:30][CH:29]=1

Participants

6

Reactant 4

HCID 795ImidazoleHCID 807Iodine2×HCID 11776TriphenylphosphineHCID 113473932-Tert-butoxycarbonylamino-4-hydroxy-butyric acid benzyl ester

Product 1

HCID 14103838Benzyl (S)-2-(Boc-amino)-4-iodobutanoateYield 44%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution of triphenylphosphine (734 mg, 2.80 mmol) and imidazole (191 mg, 2.80 mmol) in CH2Cl2 (10 ml) at rt was added iodine (711 mg, 2.80 mmol) portionwise over 5 min. The mixture first turned yellow, then brown and developed precipitate. The mixture was stirred at rt until no pieces of iodine were visible (approx. 5 min.). A solution of alcohol from step (38b) (721 mg, 2.33 mmol) in CH2Cl2 (5 ml) was added and the resulting mixture was stirred at rt for 1 h. The reaction was filtered and concentrated in vacuo. Purification by flash chromatography (silica, 0-25% EtOAc/Hexane) gave 2-tert-butoxycarbonylamino-4-iodo-butyric acid benzyl ester (430 mg, 44%) as a slightly yellow oil: 1H NMR (500 MHz, Methanol-D) δ 7.24-7.42 (m, 5 H), 5.07-5.25 (m, 2 H), 4.16-4.31 (m, 1 H), 3.12-3.29 (m, 2 H), 2.01-2.35 (m, 2 H), 1.42 (s, 9 H). LC-MS (Method A, retention time: 1.71 min), MS m/z 420 (M++1).

Workup

  1. custom(approx. 5 min.)
  2. filtrationThe reaction was filtered
  3. concentrationconcentrated in vacuo
  4. customPurification by flash chromatography (silica, 0-25% EtOAc/Hexane)

Sources & evidence

ORD record
ord-17bf2171470b4af1a8c54558edc78b1f
Source dataset
uspto-grants-2009_07
Patent number
US07557137B2

Reaction notes

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