反应详情

2-Acetylamino-7-benzoylamino-oct-4-enedioic acid dimethyl ester 143 was synthesised using standard solution-phase metathesis conditions (refer to Section 7.5.2): 6-Acetoxy-2-benzoylamino-4-hexenoic acid methyl ester 142 (50 mg, 0.16 mmol), dichloromethane (10 mL), second generation Grubbs' catalyst (5 mol %, 7 mg, 8 μmol), methyl-2-acetylamino-4-pentenoate 21a (168 mg, 0.98 mmol), 50° C., 18 h. The desired compound was obtained as a brown oil and purified via column chromatography (SiO2; EtOAc:hexane; 2:1). 1H NMR (500 MHz, CDCl3, mixture of isomers (1:1.2)): δ 1.95, s (major isomer) and 1.97, s (minor isomer), 3H, CH3; 2.42-2.70, m, 4H, H3, 6; 3.62, s (minor isomer), 3.64, s (major isomer), 3.78, s (minor isomer) and 3.79, s (major isomer), 6H, 2×OCH3; 4.63-4.66, m, 1H, H2; 4.85-4.91, m, 1H, H7; 5.35-5.49, m, 2H, H4, 5; 6.20, d, J 7.7 Hz (major isomer) and 6.34, d, J 7.5 Hz, 1H, NH (minor isomer); 6.87, t, J 7.55 Hz, 1H, NH; 7.44, t, J 7.1 Hz, 2H, H4′, 6′; 7.50, t, J 6.9 Hz, 1H, H5′; 7.84, t, J 7.9 Hz, 2H, H3′, 7′. 13C NMR (75 MHz, CDCl3, mixture of isomers (1:1.2)): δ 22.83, CH3; 34.84, 35.05, 35.38 and 35.73, C3, 6; 51.51 and 51.55, C2; 52.35, 52.46, 52.53, 52.60 and 52.66, C7, 2×OCH3; 127.18 and 127.22, C3′, 7′; 128.57 and 128.62, C4′, 6′; 128.88 and 129.00, C4, 5; 131.86 and 131.91, C5′; 133.71, C2′; 167.06, COPh; 170.03 and 170.11, COMe; 172.20, 172.21, 172.24 and 172.43, 2×COOMe. Mass Spectrum (ESI+, CH3OH): m/z 399.2 (M+Na+) C19H24N2O6Na.