Thionyl Chloride → (S)-4-Amino-5-biphenyl-4-yl-pentanoic acid ethyl ester hydrochloride

Participants

Reaction Steps

To a solution of (S)-5-Biphenyl-4-yl-4-tert-butoxycarbonylaminopentanoic acid ethyl ester [9-a, R1=Boc, R2=H, R5=Et] (115 g) in ethanol (1.1 L) at 70° C. is added thionyl chloride (32 ml) over 45 min. After a further 1.5 hours, the mixture is concentrated to dryness. The crude material is suspended in ethyl acetate and filtered to give (S)-4-Amino-5-biphenyl-4-yl-pentanoic acid ethyl ester hydrochloride[10-a, R5=Et]. 1H NMR (DMSO): 1.08 (3H, d, CH3); 1.73 (2H, m, 3-CH2); 2.35-2.52 (2H, m, 2-CH2); 2.79 (1H, dd, 5-CHH); 2.97 (1H, dd, CHH); 3.38 (1H, m, 4-CH); 3.97 (2H, q, CH2CH3); 7.30 (3H, m, aromatic); 7.40 (2H, m, aromatic); 7.58 (4H, m, aromatic); 8.15 (3H, s, NH3+). m/z: 298 (MH+, 100%); 281 (4); 235 (3).

Provenance & Evidence