Acetaldehyde → (4R,9aR)-6-(1-(RS)-Hydroxy-ethyl)-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester

HRID 11956Notes

Reaction equation

HRID 11956 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH2:20][C@@H:19]([CH3:21])[N:18]2[C@H:10]([CH2:11][C:12]3[C:17]2=[N:16][C:15]([CH2:22][O:23]CCO)=[CH:14][CH:13]=3)[CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[CH2:27]([Li])CCC.C(=O)C>C1COCC1>[C:1]([O:5][C:6]([N:8]1[CH2:20][C@@H:19]([CH3:21])[N:18]2[C@H:10]([CH2:11][C:12]3[C:17]2=[N:16][C:15]([CH:22]([OH:23])[CH3:27])=[CH:14][CH:13]=3)[CH2:9]1)=[O:7])([CH3:2])([CH3:3])[CH3:4]

Participants

5

Reactant 3

HCID 177AcetaldehydeHCID 69557393(4R,9aR)-6-(2-hydroxy-ethoxymethyl)-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester2×HCID 178418339Butyllithium

Product 1

HCID 67237860(4R,9aR)-6-(1-(RS)-Hydroxy-ethyl)-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

To a stirred solution of (4R,9aR)-6-bromo-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester (Example 5, intermediate b) (2 g) in THF (24 ml) at −78° C. was added n-butyllithium (2.72 ml, 2.5 M in hexanes) dropwise. The solution was stirred at −78° C. for 45 mins and acetaldehyde (604 μl) in THF (2 ml) was added dropwise. The solution was stirred for a further 2 hours, allowed to warm to room temperature slowly and stirred for a further 4.5 hours. The reaction was quenched with aqueous ammonium chloride (20 ml), diluted with ethyl acetate and the phases separated. The organics were washed successively with water and brine, dried (MgSO4) and concentrated in vacuo. The residue was purified by column chromatography [SiO2; isohexane-ethyl acetate (3:2)] to afford (4R,9aR)-6-(1-hydroxy-ethyl)-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester (742 mg) as a yellow oil: 1H NMR (400 MHz, CDCl3) 7.16 (1H, d, J 7 Hz), 6.35 (1H, d, J 7 Hz), 4.37–4.31 (1H, br s), 4.31–4.19 (1H, br s), 4.09–3.95 (1H, m), 3.95–3.85 (1H, m), 3.13–2.94 (2H, m), 2.79–2.55 (1H, br s), 2.54 (1H, dd, J 6 and 16 Hz), 1.48 (9H, s), 1.44 (3H, d, J 6.5 Hz), 1.25 (1.5H, R epimer, d, J 6.5 Hz) and 1.24 (1.5H, S epimer, d, J 6.5 HZ); MS (ES) 334.3 (MH+).

Workup

  1. stirringThe solution was stirred for a further 2 hours
  2. temperatureto warm to room temperature slowly
  3. stirringstirred for a further 4.5 hours
  4. customThe reaction was quenched with aqueous ammonium chloride (20 ml)
  5. additiondiluted with ethyl acetate
  6. customthe phases separated
  7. washThe organics were washed successively with water and brine
  8. dry with materialdried (MgSO4)
  9. concentrationconcentrated in vacuo
  10. customThe residue was purified by column chromatography [SiO2; isohexane-ethyl acetate (3:2)]

Sources & evidence

ORD record
ord-a6cae64ff2dc4f43a91424aa999563f4
Source dataset
uspto-grants-2006_08
Patent number
US07098337B2

Reaction notes

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