Diisopropylamine → 2-amino-3-hydroxy-6-(N-benzoyl)aminoheptanedioic acid, diethyl ester

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Reaction Conditions

Reaction Steps

Diisopropylamine (2.34 ml, 16.7 mmoles) is added to anhydrous THF (75 ml) and cooled to -10° C. At this point 2.24M n-BuLi (6.8 ml, 15.2 mmoles) is added slowly. After complete addition the reaction mixture is stirred for 10 minutes before being cooled to -78° C. At that temperature ethyl N-benzylideneglycinate (4) (2.9 g, 15.2 mmoles) is added and stirring is allowed to proceed for 15 minutes before aldehyde (8) (4.0 g, 15.2 mmoles), dissolved in anhydrous THF (25 ml), is added dropwise to the yellow anion. After complete addition the reaction is stirred another 11/2 hours before being poured into cold 5% aqueous NH4Cl. This mixture is extracted with CHCl3 (3×100 ml). The combined extracts are washed with saturated aqueous NaCl, dried over MgSO4, filtered and evaporated to dryness. The oily residue is taken up in THF (300 ml) and shaken with 5% aqueous HCl (200 ml) in a separatory funnel. This mixture is washed with Et2O (3×100 ml), basified with solid NaHCO3 and extracted with CHCl3 (3×150 ml). The combined extracts are washed with saturated aqueous NaCl (1×150 ml), dried over MgSO4, filtered and evaporated to dryness in vacuo to yield 4.0 g (72% yield) of the desired compound as a yellow glass. 'H-N.M.R. (CHCl3 /TMS): δ=1.20 (t, 3H, --CH2CH3); 1.28 (t, 3H, --CH2CH3 ); 1.45-2.20 (m, 4H, --CH2CH2 --); 2.46 (broad s, 2H, --NH2); 3.18-4.00 (m, 2H, >CH--NH2, CHOH); 4.19 (q, 2H, --CH2CH3); 4.25 (q, 2H, --CH2CH3); 4.53-5.08 (m, 1H, >CH--NH--); 7.05-7.97 ppm (m, 5H, Ph).

Provenance & Evidence