Inhibition of nNOS Activity by Kynurenines
J ournal of Medicinal Chemistry, 2002, Vol. 45, No. 2 271
1
859, 814, 755, and 698 cm-1; H NMR (CDCl3) δ 1.25 (6H, t,
2-P r opion am ido-4-(3-m eth oxyph en yl)-4-oxobu tyr ic acid
(18b): (93%); mp 119-122 °C; IR (KBr) 3346, 3068, 2844,
1739, 1685, 1616, 1550, 1487, 895, 781, and 686 cm-1; 1H NMR
(CD3OD) δ 1.02 (3H, t, J ) 7.6), 2.17 (1H, q, J ) 7.6), 2.20
(1H, q, J ) 7.6), 3.52 (1H, dd, J ) 4.1, 8.1), 3.65 (1H, dd, J )
4.3, 8.1), 3.76 (3H, s), 4.9 (1H, pt, J ) 4.1, 4.3), 7.02-7.45 (5H,
m), and 9.75 (1H, bs); 13C NMR (CD3OD) δ 9.60, 29.32, 40.58,
49.09, 55.43, 112.34, 120.26, 121.05, 129.75, 137.34, 159.79,
174.90, 176.03, and 198.45; MS (LSIMS) m/z 302.100335
(M+Na)+, Calcd. mass for C14H17NO5Na: 302.100443 (devia-
tion 0.4 ppm); Anal. C14H17NO5 (C, H, N).
J ) 7.1), 1.99 (3H, s), 3.77 (3H, s), 4.25 (2H, s), 4.27 (4H, q,
J ) 7.1), 4.43 (2H, d, J ) 5.9), 6.58-7.36 (9H, m), and 8.87
(1H, t, J ) 5.9); 13C NMR (CDCl3) δ 13.95, 23.05, 42.92, 47.01,
56.19, 62.82, 64.25, 113.85, 113.99, 116.54, 125.07, 126.90,
127.16, 128.68, 138.96, 146.56, 149.23, 167.68, 169.40, and
198.14; MS (LSIMS) m/z 493.194955 (M+Na)+, Calcd. mass
for C25H30N2O7Na: 493.195071 (deviation 0.2 ppm).
P r ep a r a tion of r-Am id o-ω-ben zoyl Su bstitu ted Ca r -
boxylic Acid , 15a , 15c, 16a , 17a , 18a -g, 19a -b, 20a -c, 21c,
a n d 22c. Gen er a l Meth od . 2-Substituted amidomalonic acid
diethyl esters 7a , 7c, 8a , 9a , 10a -g, 11a -b, 12a -c, 13c, or
14c (2.74 mmol) were stirred with 10 mL of 1.00 N sodium
hydroxide at room temperature until solution was complete
(approximately 2 h). Glacial acetic acid (0.57 mL) was then
added, and the solution was boiled for 20 min (evolution of
carbon dioxide). The cooled solution was washed with water
and rotaevaporated off several times to eliminate the acid. The
residue was purified by flash chromatography (CHCl3: metha-
nol 7:3), generally yielding a quantitative amount of carboxylic
acids.
2-Bu tyr a m id o-4-(3-m eth oxyp h en yl)-4-oxobu tyr ic a cid
(18c): (70%); mp 100-102 °C; IR (KBr) 3323, 3063, 2842,
1750, 1697, 1602, 1556, 1486, 788, 775, and 682 cm-1 1H
;
NMR (CDCl3) δ 0.89 (3H, t, J ) 7.3), 1.62 (2H, m, J ) 7.3),
2.20 (2H, t, J ) 7.3), 3.58 (1H, dd, J ) 3.7, 18.4), 3.77 (1H, dd,
J ) 3.6, 18.4), 3.83 (3H, s), 5.02 (1H, pt, J ) 3.6, 3.7), 6.76-
7.52 (5H, m), and 9.76 (1H, bs); 13C NMR (CDCl3) δ 13.67,
19.06, 38.31, 40.62, 48.24, 55.51, 112.22, 120.62, 121.07,
129.85, 137.16, 159.92, 173.77, 175.22, and 198.11; MS (LSIMS)
m/z 316.116052 (M+Na)+, Calcd. mass for C15H19NO5Na:
316.116093 (deviation 0.1 ppm); Anal. C15H19NO5 (C, H, N).
2-Acet a m id o-4-(2-a m in o-5-m et h oxyp h en yl)-4-oxob u -
tyr ic a cid (15a ): (73%); mp 115-118 °C; IR (KBr) 3434, 3358,
2-Ben za m id o-4-(3-m eth oxyp h en yl)-4-oxobu tyr ic a cid
(18d ): (100%); mp 166-168 °C; IR (KBr) 3325, 3017, 2963,
2840, 1706, 1681, 1640, 1582, 1535, 1487, 788, 717, and 685
3080, 2935, 2839, 1715, 1649, 1592, and 838 cm-1; H NMR
1
(CD3OD) δ 1.97 (3H, s), 3.44 (1H, dd, J ) 5.4, 17.4), 3.52 (1H,
dd, J ) 5.6, 17.4), 3.72 (3H, s), 4.74 (1H, pt, J ) 5.4, 5.6), 6.69
(1H, d, J ) 9.1), 6.93 (1H, dd, J ) 2.9, 9.1), and 7.19 (1H, d,
J ) 2.9); 13C NMR (CD3OD) δ 22.70, 42.25, 52.06, 55.41, 114.1,
118.23, 119.98, 125.05, 147.37, 151.22, 173.14, 176.75, and
200.74; MS (LSIMS) m/z 303.095659 (M+Na)+, Calcd. mass
for C13H16N2O5Na: 303.095692 (deviation 0.1 ppm); Anal.
cm-1 1H NMR (CD3OD) δ 3.69 (2H, m), 3.83 (3H, s), 5.14
;
(1H, m) and 7.15-7.83 (9H, m); 13C NMR (CD3OD) δ
41.20, 50.59, 55.89, 113.59, 120.73, 121.81, 128.40, 129.56,
130.89, 132.88, 135.21, 139.22, 161.43, 170.01, 175.10, and
198.81; MS (LSIMS) m/z 350.101513 (M+Na)+, Calcd. mass
for C18H17NO5Na: 350.100443 (deviation -3.6 ppm); Anal.
C
13H16N2O5 (C, H, N).
C
18H17NO5 (C, H, N).
2-Bu tyr a m id o-4-(2-a m in o-5-m eth oxyp h en yl)-4-oxobu -
2-Cycloh exa n eca r b oxa m id o-4-(3-m et h oxyp h en yl)-4-
tyr ic a cid (15c): (70%); mp 82-85 °C; IR (KBr) 3446, 2966,
2840, 2354, 1715, 1645, 1591, 992, 838, and 675 cm-1; 1H NMR
(CD3OD) δ 0.90 (3H, t, J ) 7.4), 1.60 (2H, m, J ) 7.4), 2.18
(2H, t, J ) 7.4), 3.42 (1H, dd, J ) 4.5, 16.9), 3.52 (1H, dd, J )
6.5, 16.9), 3.75 (3H, s), 4.76 (1H, dd, J ) 4.5, 6.5), 6.69 (1H, d,
J ) 9.0), 6.94 (1H, dd, J ) 2.8, 9.0), and 7.23 (1H, d, J ) 2.8);
13C NMR (CD3OD) δ 13.94, 20.21, 39.03, 42.46, 51.59, 56.42,
114.09, 118.43, 119.92, 124.93, 147.32, 151.27, 175.44, 176.98,
and 200.54; MS (LSIMS) m/z 309.145071 (M+1)+, Calcd. mass
oxobu tyr ic a cid (18e): (70%); mp 121-124 °C; IR (KBr)
3445, 3022, 2485, 1699, 1689, 1552, 1488, 946, 883, 785, and
686 cm-1; 1H NMR (CD3OD) δ 1.28 (5H, m), 1.73 (5H, m), 2.17
(1H, m), 3.48 (2H, d, J ) 5.6), 3.83 (3H, s), 4.67 (1H, t, J )
5.6), and 7.13-7.58 (4H, m); 13C NMR (CD3OD) δ 26.82, 30.28,
30.79, 46.35, 42.36, 52.12, 55.87, 113.60, 120.41, 121.86,
130.74, 139.71, 161.36, 177.50, 178.24, and 199.77; MS (LSIMS)
m/z 334.164562 (M+1)+, Calcd. mass for C18H24NO5: 334.165448
(deviation 2.7 ppm), Anal. C18H23NO5 (C, H, N).
for
C15H21N2O5: 309.145047 (deviation -0.1 ppm); Anal.
2-tr a n s-Cr ot on a m id o-4-(3-m et h oxyp h en yl)-4-oxob u -
tyr ic a cid (18f): (85%); mp 164-166 °C; IR (KBr) 3360, 2948,
1727, 1689, 1667, 1612, 1536, 1486, 972, 868, 787, and 687
C
15H20N2O5 (C, H, N).
2-Aceta m id o-4-(5-m eth oxy-2-d im eth yla m in op h en yl)-4-
oxobu tyr ic a cid (16a ): (100%); mp 64-65 °C; IR (KBr) 3324,
cm-1 1H NMR (CD3OD) δ 1.84 (3H, m, J ) 1.6, 6.9), 3.58
;
3062, 1740, 1706, 1690, 1672, 1500, 867, and 696 cm-1 1H
;
(2H, d, J ) 5.6), 3.64 (3H, s), 4.56 (1H, t, J ) 5.6), 5.99 (1H,
dd, J ) 6.9, 15.3), 6.8 (1H, m, J ) 1.6, 15.3), and 7.16-7.59
(4H, m); 13C NMR (CD3OD) δ 17.81, 41.50, 49.93, 55.90, 113.56,
120.70, 121.76, 130.87, 139.22, 161.46, 125.70, 141.57, 172.02,
176.50, and 198.61; MS (LSIMS) m/z 314.100419 (M+Na)+,
Calcd. mass for C15H17NO5Na: 314.100443 (deviation 0.1 ppm);
Anal. C15H17NO5 (C, H, N).
NMR (CDCl3) δ 1.99 (3H, s), 2.83 (6H, s), 3.47 (1H, m), 3.80
(3H, s), 3.84 (1H, m), 4.70 (1H, bd), 6.98-7.35 (4H, m), and
8.0 (1H, bs); 13C NMR (CDCl3) δ 23.06, 43.70, 46.36, 50.26,
55.86, 113.26, 118.69, 120.65, 134.47, 142.91, 156.39, 170.69,
174.69, and 202.92; MS (LSIMS) m/z 331.126974 (M+Na)+,
Calcd. mass for C15H20N2O5Na 331.126992 (deviation 0.1 ppm);
Anal. C15H20N2O5 (C, H, N).
2-Cyclop r op a n eca r boxa m id o-4-(3-m eth oxyp h en yl)-4-
oxobu tyr ic a cid (18g): (80%); mp 121-122 °C; IR (KBr)
3377, 3935, 1737, 1689, 1629, 1547, 1487, 872, 788, and 688
2-Acet a m id o-4-(2-b en zyla m in o-5-m et h oxyp h en yl)-4-
oxobu tyr ic a cid (17a ): (70%); mp 68-70 °C; IR (KBr) 3343,
3086, 2931, 2857, 1731, 1643, 1619, 1518, 813, and 750 cm-1
;
cm-1 1H NMR (CD3OD) δ 0.69-0.88 (4H, m), 1.63 (1H, m),
;
1H NMR (CDCl3) δ 1.99 (3H, s), 3.53 (1H, m), 3.73 (3H, s),
3.75 (1H, m), 4.39 (2H, s), 4.96 (1H, pt), and 6.57-7.32 (10H,
m); 13C NMR (CDCl3) δ 22.98, 46.99, 56.06, 113.94, 114.10,
116.27, 124.95, 126.94, 127.17, 128.71, 138.86, 146.63, 149.09,
171.06, 176.40, and 199.20; MS (EI) m/z 370.152836 (M+),
Calcd. mass for C20H22N2O5 370.152872 (deviation 0.1 ppm);
Anal. C20H22N2O5 (C, H, N).
3.55 (2H, d, J ) 5.4), 3.83 (3H, s), 4.92 (1H, t, J ) 5.4)
and 6.70-7.59 (4H, m); 13C NMR (CD3OD) δ 7.53, 7.57,
14.67, 41.50, 49.86, 55.90, 113.55, 120.71, 121.77, 130.89,
139.17, 161.43, 174.68, 176.40, and 198.56; MS (LSIMS)
m/z 314.100536 (M+Na)+, Calcd. mass for C15H17NO5Na:
314.100443 (deviation -0.3 ppm); Anal. C15H17NO5 (C, H, N).
2-Aceta m id o-4-(3-n itr op h en yl)-4-oxobu tyr ic a cid (19a ):
(86%); mp 70-74 °C; IR (KBr) 3395, 3092, 1696, 1659, 1565,
1532, 1222, 810, 736, and 672 cm-1; 1H NMR (CD3OD) δ 1.90
(3H, s), 3.51 (1H, dd, J ) 6.4, 17.0), 3.59 (1H, dd, J ) 5.1,
17.0), 4.72 (1H, dd, J ) 5.1, 6.4), 7.76 (1H, m), 8.41 (2H, m)
and 8.75 (1H, m); 13C NMR (CD3OD) δ 22.74, 42.68, 52.56,
123.71, 128.21, 131.26, 135.09, 139.66, 149.88, 172.76, 180.70,
and 198.09; MS (LSIMS) m/z 303.059235 (M+Na)+, Calcd.
mass for C12H12N2O6Na: 303.059306 (deviation 0.2 ppm); Anal.
C12H12N2O6 (C, H, N).
2-Acet a m id o-4-(3-m et h oxyp h en yl)-4-oxob u t yr ic a cid
(18a ): (100%); mp 152-155 °C; IR (KBr) 3376, 3083, 2839,
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1681, 1600, 1488, 869, 787, and 685 cm-1; H NMR (CD3OD)
δ 1.78 (3H, s), 3.22 (1H, dd, J ) 7.0, 16.2), 3.36 (1H, dd, J )
5.4, 16.2), 3.79 (3H, s), 4.54 (1H, dd, J ) 5.4, 7.0) and 7.14-
7.85 (5H, m); 13C NMR (CD3OD) δ 22.66, 41.61, 50.59, 55.24,
112.47, 118.81, 120.51, 129.66, 138.29, 159.30, 168.73, 175.21,
and 197.48; MS (LSIMS) m/z 310.066709 (M-1+Na2)+, Calcd.
mass for C13H14NO5Na2: 310.066737 (deviation 0.1 ppm); Anal.
C
13H15NO5 (C, H, N).