Synthesis of Esters
2463
(CH2), 14.7 (CH3). Anal. calcd. for C9H12N2O5: C, 47.37; H, 5.30; N, 12.28.
Found: C, 47.41; H, 5.25; N, 12.20.
4-(Carboxymethyl-amino)-1-methyl-5-oxo-2,5-dihydro-1H-pyrrole-2,3-
dicarboxylic acid diethyl ester 12a: White crystals; 125 mg (80%);
mp ¼ 103–1048C; IR: 3370–3110 (NH, OH), 1742, 1725, 1698 and 1658
1
(C55O); H NMR (CDCl3) d: 9.92 (br, 1H, OH), 6.79 (br, 1H, NH), 4.66
(m, 1H, NCH2CO2H), 4.61 (s, 1H, CH), 4.51 (m, 1H, NCH2CO2H), 4.21
(q, JH-H ¼ 7.3 Hz, 2H, CH2O), 4.18 (q, JH-H ¼ 7.1 Hz, 2H, CH2O), 2.87
(s, 3H, CH3N), 1.29 (t, JH-H ¼ 7.1 Hz, 3H, CH3), 1.27 (t, JH-H ¼ 7.3 Hz,
3H, CH3); 13C NMR (CDCl3) d: 174.0 (CO), 168.7 (CO), 165.8 (CO),
164.6 (CO), 146.8 (C4), 99.3 (C3), 61.8 (CH2O), 61.5 (CH), 60.2 (CH2O),
44.0 (CH2), 28.2 (CH3N), 14.2 (CH3), 14.1 (CH3). Anal. calcd. for
C13H18N2O7: C, 49.68; H, 5.77; N, 8.91. Found: C, 49.66; H, 5.78; N, 8.85.
4-(Carboxymethyl-amino)-1-isobutyl-5-oxo-2,5-dihydro-1H-pyrrole-2,3-
dicarboxylic acid diethyl ester 12b: White crystals; 135 mg (76%);
mp ¼ 77–788C; IR: 3360–3100 (NH, OH), 1745, 1722, 1699 and 1661
1
(C55O); H NMR (CDCl3) d: 9.79 (br, 1H, OH), 7.12 (br, 1H, NH), 4.76
(m, 1H, NCH2CO2H), 4.73 (s, 1H, CH), 4.57 (m, 1H, NCH2CO2H), 4.22
(q, JH-H ¼ 7.1 Hz, 2H, CH2O), 4.20 (q, JH-H ¼ 7.1 Hz, 2H, CH2O), 3.53
(dd, JH-H ¼ 13.9 and 8.7 Hz, 1H, CH2N), 2.82 (dd, JH-H ¼ 13.9 and 6.3 Hz
1H, CH2N), 1.95 (m, 1H, CH), 1.28 (t, JH-H ¼ 7.1 Hz, 3H, CH3), 1.26
(t, JH-H ¼ 7.1 Hz, 3H, CH3), 0.93 (d, JH-H ¼ 6.6 Hz 3H, CH3), 0.84
(d, JH-H ¼ 6.8 Hz, 3H, CH3); 13C NMR (CDCl3) d: 174.4 (CO), 168.9 (CO),
166.0 (CO), 164.4 (CO), 146.4 (C4), 99.1 (C3), 61.8 (CH2O), 61.2 (CH),
60.0 (CH2O), 49.1 (CH2), 43.8 (CH2), 27.1 (CH), 20.0 (CH3), 19.6 (CH3),
14.1 (CH3), 14.0 (CH3). Anal. calcd. for C16H24N2O7: C, 53.92; H, 6.79;
N, 7.86. Found: C, 53.75; H, 6.51; N, 7.80.
4-(Carboxymethyl-amino)-5-oxo-1-phenyl-2,5-dihydro-1H-pyrrole-2,3-
dicarboxylic acid diethyl ester 12c: White crystals; 155 mg (82%);
mp ¼ 144–1458C; IR: 3350–3105 (NH, OH), 1743, 1720, 1700 and 1660
1
(C55O); H NMR (CDCl3) d: 10.20 (br, 1H, OH), 8.55 (br, 1H, NH), 7.46
(m, 2H, Ph), 7.25 (m, 2H, Ph), 7.12 (m, 1H, Ph), 5.28 (s, 1H, CH), 4.69
(m, 1H, NCH2CO2H), 4.48 (m, 1H, NCH2CO2H), 4.15 (q, JH-H ¼ 7.1 Hz,
2H, CH2O), 3.97 (q, JH-H ¼ 7.1 Hz, 2H, CH2O), 1.21 (t, JH-H ¼ 7.1 Hz, 3H,
CH3), 0.99 (t, JH-H ¼ 7.1 Hz, 3H, CH3); 13C NMR (CDCl3) d: 174.7 (CO),
168.5 (CO), 168.0 (CO), 164.4 (CO), 146.4 (C4), 136.1, 129.0, 126.3 and
122.1 (Ph), 99.3 (C3), 61.8 (CH2O), 61.6 (CH), 60.3 (CH2O), 44.0 (CH2),
14.1 (CH3), 13.8 (CH3). Anal. calcd. for C18H20N2O7: C, 57.44; H, 5.36;
N, 7.44. Found: C, 57.37; H, 5.21; N, 7.29.
1-Benzyl-4-(carboxymethyl-amino)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-
dicarboxylic acid diethyl ester 12d: White crystals; 170 mg (87%); mp ¼
102–1038C; IR: 3360-3095 (NH, OH), 1741, 1722, 1699 and 1659 (C55O);
1H NMR (CDCl3) d: 10.21 (br, 1H, OH), 7.35–7.22 (m, 5H, Ph), 7.04 (br,
1H, NH), 4.95 (d, JH-H ¼ 15.1Hz, 1H, CH2Ph), 4.80 (m, 1H, NCH2CO2H),
4.60 (m, 1H, NCH2CO2H), 4.58 (s, 1H, CH), 4.16 (q, JH-H ¼ 7.1 Hz, 2H,