5-Methylpyrazin-2-amine → (S)-2-hydroxy-N-(5-methylpyrazin-2-yl)-3-((R)-1-(triisopropylsilyloxy)propan-2-yloxy)propanamide

HRID 1098259Notes

Reaction equation

HRID 1098259 reaction equation
C[Al](C)C.[CH3:5][C:6]1[N:7]=[CH:8][C:9]([NH2:12])=[N:10][CH:11]=1.[OH:13][C@H:14]([CH2:19][O:20][C@@H:21]([CH3:34])[CH2:22][O:23][Si:24]([CH:31]([CH3:33])[CH3:32])([CH:28]([CH3:30])[CH3:29])[CH:25]([CH3:27])[CH3:26])[C:15](OC)=[O:16]>C1(C)C=CC=CC=1>[OH:13][C@@H:14]([CH2:19][O:20][C@H:21]([CH3:34])[CH2:22][O:23][Si:24]([CH:28]([CH3:30])[CH3:29])([CH:31]([CH3:33])[CH3:32])[CH:25]([CH3:26])[CH3:27])[C:15]([NH:12][C:9]1[CH:8]=[N:7][C:6]([CH3:5])=[CH:11][N:10]=1)=[O:16]

Participants

5

Reactant 3

HCID 3132155-Methylpyrazin-2-amineHCID 16682925TrimethylaluminumHCID 86640847(R)-methyl 2-hydroxy-3-((S)-1-(triisopropylsilyloxy)propan-2-yloxy)propanoate

Product 1

HCID 57504703(S)-2-hydroxy-N-(5-methylpyrazin-2-yl)-3-((R)-1-(triisopropylsilyloxy)propan-2-yloxy)propanamideYield 56.5%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Conditions

Temperature
0 °C

Procedure

Trimethylaluminium (2M solution in toluene) (5.98 mL, 11.96 mmol) was added to 5-methylpyrazin-2-amine (1.305 g, 11.96 mmol) in toluene (20 mL) cooled to 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 20 minutes. (R)-methyl 2-hydroxy-3-((S)-1-(triisopropylsilyloxy)propan-2-yloxy)propanoate (Intermediate AU5) (2 g, 5.98 mmol) in toluene (6 mL) was added and the reaction was allowed to warm to room temperature and then refluxed for 6 hours. The reaction mixture was allowed to cool and concentrated in vacuo. The residue was neutralised with citric acid (1M, aq.) and then diluted with water (25 mL) and extracted with EtOAc (2×50 mL). The combined organics were washed with brine (20 mL), then dried (MgSO4) and evaporated. The crude product was purified by flash silica chromatography, eluting with 30 to 50% EtOAc in isohexane to afford the product (1.390 g, 56.5%). 1H NMR (400 MHz, CDCl3) δ 1.04-1.17 (24H, m), 2.54 (3H, s), 3.62-3.67 (3H, m), 3.81-3.85 (1H, m), 4.05-4.09 (1H, m), 4.22 (1H, d), 4.34 (1H, q), 8.13 (1H, d), 9.12 (1H, s), 9.44 (1H, d); m/z (ES+) (M+H)+412.34; HPLC tR=3.82 min.

Workup

  1. temperatureto warm to room temperature
  2. temperaturerefluxed for 6 hours
  3. temperatureto cool
  4. concentrationconcentrated in vacuo
  5. additiondiluted with water (25 mL)
  6. extractionextracted with EtOAc (2×50 mL)
  7. washThe combined organics were washed with brine (20 mL)
  8. dry with materialdried (MgSO4)
  9. customevaporated
  10. customThe crude product was purified by flash silica chromatography
  11. washeluting with 30 to 50% EtOAc in isohexane

Sources & evidence

ORD record
ord-0b40a3ccaedb4ee29c7273cf8cd671bd
Source dataset
uspto-grants-2012_03
Patent number
US08143263B2

Reaction notes

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