NEW 3-AMINO-3-ARYLPROPIONIC ACID DERIVATIVES
219
the resulting precipitate was ®ltered off, washed
with dry ether and recrystallized from methanol-
ether (50:50, v=v).
2pyridine). Calculated for C14H15ClN2O3S: C,
51Á45; H, 4Á63; N, 8Á57. Found: C, 51Á40; H, 4Á68;
N, 8Á56%.
3-Carbamoyl-1-(2-methoxycarbonyl-1-phenylethyl)
pyridinium chloride (5a). Orange crystals (54%);
mp 130ꢀC; IR (KBr) n: 3100 (NH), 1720
General procedure for the preparation of methyl 3-
(3-carbamoyl-4H-pyridin-1-yl)-3-arylpropionates
(6a±c)
1
(COOCH3), 1660 (CONH2); H NMR (d6-DMSO)
d: 3Á54 (3H, s, CH3O), 3Á85 (1H, dd, J 17Á60 and
6Á00 Hz, H-2a), 4Á22 (1H, dd, J 17Á60 and
9Á00 Hz, H-2b), 6Á61 (1H, dd, J 9Á00 and
6Á00 Hz, H-1), 7Á43 (3H, m, H-phenyl), 7Á84 (2H,
m, H-phenyl), 8Á22 (1H, s, NH), 8Á31 (1H, t,
J 6Á70 Hz, H-5pyridine), 9Á06 (1H, d,
J 6Á70 Hz, H-4pyridine), 9Á24 (1H, s, NH), 9Á67
(1H, d, J 6Á70 Hz, H-6pyridine), 10Á15 (1H, s, H-
2pyridine); 13C NMR (d6-DMSO) d: 36Á0 (C-2),
52Á0 (CH3), 70Á4 (C-3), 128Á1 (C-3 and C-5phenyl),
128Á4 (C-4phenyl), 129Á2 (C-2 and C-6phenyl),
129Á8 (C-1pyridine), 134Á1 (C-5pyridine), 135Á9
(C-4pyridine), 143Á7 (C-3pyridine), 145Á1 (C-6pyr-
idine), 145Á7 (C-2pyridine), 162Á3 (CO), 169Á9
(CO). Calculated for C16H17ClN2O3: C, 59Á9; H,
5Á30; N, 8Á73. Found: C, 60Á07; H, 5Á38; N, 8Á92%.
To a solution of 3-carbamoyl-1-(2-methoxy-
carbonyl-1-arylethyl)pyridinium chlorides (5a±c)
(8 mmol) in 300 mL deaerated water and 300 mL
ethyl acetate was added a mixture of sodium
hydrogenocarbonate (80 mmol) and sodium
dithionite (80 mmol). The system was maintained
under an argon stream and was stirred for 2 h. The
organic layer was separated and the aqueous layer
extracted with ethyl acetate (2 6 100 mL). The
combined organic layers were washed with cold
degassed water (2 6 500 mL), dried over magne-
sium sulphate and evaporated under reduced pres-
sure to give 4a±c, which was puri®ed by
chromatography on silica gel using CHCl3
CH3OH (98:2, v=v) as eluent.
Methyl 3-(3-carbamoyl-4H-pyridin-1-yl)-3-phenyl-
propionate (6a). Yellow crystals (53%); mp 45ꢀC;
IR (KBr) n: 3285, 3200 (NH2), 1735 (COOCH3),
3-Carbamoyl-1-(2-methoxycarbonyl-1-thien-2-yl-
ethyl)pyridinium chloride (5b). Orange crystals
(52%); mp 153ꢀC; IR (KBr) n: 3250 (NH), 1705
1
1685 (CONH2); H NMR (d6-DMSO) d: 2Á90 (2H,
1
(COOCH3), 1630 (CONH2); H NMR (d6-DMSO)
m, H-4pyridine), 3Á11 (2H, m, H-2), 3Á59 (3H, s,
CH3O), 4Á56 (1H, m, H-5pyridine), 4Á77 (1H, dd,
J 8Á10 and 7Á40 Hz, H-3), 6Á02 (1H, d,
J 8Á00 Hz, H-6pyridine), 6Á62 (2H, bs, NH2),
7Á04 (1H, s, H-2pyridine), 7Á39 (5H, m, H-phenyl);
13C NMR (d6-DMSO) d: 22Á7 (CH2), 36Á7 (CH2),
51Á6 (CH3), 61Á5 (CH), 101Á1 (C-5pyridine), 102Á2
(C-6pyridine), 126Á8 (C-3 and C-5phenyl), 127Á7
(C-2pyridine), 127Á9 (C-3pyridine), 128Á6 (C-2 and
C-6phenyl), 136Á1 (C-4phenyl), 139Á8 (C-1phenyl),
169Á1 (CO), 170Á7 (CO). Calculated for C16H18
N2O3: C, 67Á12; H, 6Á34; N, 9Á78. Found: C,
67Á26; H, 6Á61; N, 9Á80%.
d: 3Á56 (3H, s, CH3O), 3Á90 (1H, dd, J 15Á80 and
6Á10 Hz, H-2a), 4Á10 (1H, dd, J 15Á80 and
9Á10 Hz, H-2b), 6Á80 (1H, dd, J 9Á10 and
6Á10 Hz, H-1), 6Á99 (1H, dd, J 4Á80 and
3Á20 Hz, H-40), 7Á10 (1H, d, J 3Á20 Hz, H-30),
7Á70 (1H, d, J 4Á80 Hz, H-50), 8Á20 (1H, s, NH),
8Á30 (1H, t, J 7Á10 Hz, H-5pyridine), 9Á09 (1H, s,
H-2pyridine), 9Á21 (1H, d, J 7Á10 Hz, H-4pyri-
dine), 9Á50 (1H, d, J 6Á40 Hz, H-6pyridine), 9Á98
(1H, s, NH). Calculated for C14H15ClN2O3S: C,
51Á45; H, 4Á63; N, 8Á57. Found: C, 51Á21; H, 4Á65;
N, 8Á60%.
3-Carbamoyl-1-(2-methoxycarbonyl-1-thien-3-yl-
ethyl)pyridinium chloride (5c). Orange crystals
(63%); mp 158ꢀC; IR (KBr) n: 3360 (NH), 1735
Methyl 3-(3-carbamoyl-4H-pyridin-1-yl)-3-thien-2-
ylpropionate (6b). Yellow oil (69%); IR (KBr) n:
3320, 3290 (NH2), 1695 (COOCH3), 1655
1
1
(COOCH3), 1655 (CONH2); H NMR (d6-DMSO)
(CONH2); H NMR (d6-DMSO) d: 2Á90 (2H, m,
d: 3Á52 (3H, s, CH3O), 3Á81 (1H, dd, J 17Á50 and
5Á90 Hz, H-2a), 4Á15 (1H, dd, J 17Á50 and
9Á00 Hz, H-2b), 6Á66 (1H, dd, J 9Á00 and
5Á90 Hz, H-1), 7Á49 (1H, dd, J 5Á10 and
1Á00 Hz, H-50), 7Á60 (1H, dd, J 5Á10 and
2Á90 Hz, H-40), 8Á10 (1H, s, NH), 8Á13 (1H, dd,
J 2Á90 and 1Á00 Hz, H-20), 8Á28 (1H, t,
J 6Á40 Hz, H-5pyridine), 9Á04 (1H, d,
J 6Á40 Hz, H-4pyridine), 9Á20 (1H, s, NH), 9Á62
(1H, d, J 6Á40 Hz, H-6pyridine), 10Á12 (1H, s, H-
H-4pyridine), 3Á10 (1H, dd, J 15Á80 and 6Á60 Hz,
H-2a), 3Á13 (1H, dd, J 15Á80 and 9Á70 Hz, H-2b),
3Á60 (3H, s, CH3O), 4Á60 (1H, m, H-5pyridine),
4Á98 (1H, dd, J 9Á70 and 6Á60 Hz, H-3), 5Á98 (1H,
d, J 7Á90 Hz, H-6pyridine), 6Á61 (2H, bs, NH2),
6Á97 (1H, s, H-2pyridine), 6Á99 (1H, dd, J 4Á80
and 3Á10 Hz, H-4thienyl), 7Á08 (1H, d, J 4Á80 Hz,
H-3thienyl), 7Á46 (1H, d, J 3Á10 Hz, H-5thienyl).
Calculated for C14H16N2O3S: C, 57Á52; H, 5Á52; N,
9Á58. Found: C, 57Á69; H, 5Á47; N, 9Á61%.