Reaction Steps
In a similar fashion 4(R)-Acetyl-5-[4-methoxy-3-(3-methoxy-propoxy)-phenyl]-pyrrolidine-2-carboxylic acid benzhydryl ester, IVa is prepared as a racemate from {[1-[4-Methoxy-3-(3-methoxy-propoxy)-phenyl]-meth-(E)-ylidene]-amino}-acetic acid benzhydryl ester. 1H-NMR, δ CDCl3: 7.45-7.25 (10H, m, Ph), 7.01 (1H, Brs, NH), 6.80 (3H, m, Ph), 4.55 (1H, d, NCHCO), 4.10-4.03 (3H, m, CH2O), 3.45 (1H, q, CHCO), 3.35 (3H, s, MeO), 2.45 (1H, dd, CH), 2.35 (1H, dd, CH), 2.10-2.05 (5H, m, CH2+CH3), 1.65 (3H, s, CH3). The epimer at the 4 position, 4(S)-Acetyl-5-[4-methoxy-3-(3-methoxy-propoxy)-phenyl]-pyrrolidine-2-carboxylic acid benzhydryl ester 1H-NMR, δ CDCl3: 7.40-7.25 (10H, m, Ph), 6.941 (1H, Brs, NH), 6.80 (3H, m, Ph), 4.68 (1H, d, NCHCO), 4.35 (1H, dd, PhCHN), 4.10-4.03 (3H, m, CH2O+CH), 3.85 (3H, s, MeO), 3.8 (2H, t, CH2C), 3.38-3.30 (4H, m, MeO+CHCO), 2.75 (2H, m, CH2), 2.08 (5H, m, CH2+CH3), 1.58 (3H, s, CH3), can also be isolated from this reaction.
