Ammonium Chloride → (2R,5S)-2-Isopropyl-3,6-dimethoxy-5-(4,4,4-trifluoro-3-phenyl-butyl)-2,5-dihydro-pyrazine

HRID 885159

Reaction equation

HRID 885159 reaction equation
[CH3:1][O:2][C:3]1[C@@H:4]([CH:11]([CH3:13])[CH3:12])[N:5]=[C:6]([O:9][CH3:10])[CH2:7][N:8]=1.C([Li])(C)(C)C.I[CH2:20][CH2:21][CH:22]([C:27]1[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=1)[C:23]([F:26])([F:25])[F:24].[Cl-].[NH4+]>O1CCCC1>[CH:11]([C@@H:4]1[C:3]([O:2][CH3:1])=[N:8][C@@H:7]([CH2:20][CH2:21][CH:22]([C:27]2[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=2)[C:23]([F:25])([F:26])[F:24])[C:6]([O:9][CH3:10])=[N:5]1)([CH3:13])[CH3:12]

Participants

6

Procedure

A solution of (R)-(−)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine (1.1 g) in tetrahydrofuran (25 ml) was cooled to −70° C., then tert.butyllithium (1.7 M in pentane, 3.88 ml) was added and the mixture was stirred for 1 hour. A solution of (3-iodo-1-trifluoromethyl-propyl)-benzene (1.98 g) in tetrahydrofuran (7 ml) was added slowly and the mixture was stirred overnight at −70° C. At room temperature saturated ammonium chloride solution was added and the mixture was extracted three times with ether. The combined organic layers were dried (MgSO4), filtered and evaporated. The residue was purified by column chromatography (SiO2, heptane/EtOAc=9:1 to yield a yellow liquid, (1.86 g, 83%).

Workup

  1. stirringthe mixture was stirred overnight at −70° C
  2. extractionthe mixture was extracted three times with ether
  3. dry with materialThe combined organic layers were dried (MgSO4)
  4. filtrationfiltered
  5. customevaporated
  6. customThe residue was purified by column chromatography (SiO2, heptane/EtOAc=9:1
  7. customto yield a yellow liquid, (1.86 g, 83%)

Sources & evidence

ORD record
ord-8b979149bfaf420d84f4f17b56e20eb0
Source dataset
uspto-grants-2012_08
Patent number
US08242153B2

Linked notes

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