638 J ournal of Medicinal Chemistry, 2002, Vol. 45, No. 3
Liu et al.
N-CH3), 4.40 (br, 2H, CH2NH), 5.10 (s, 2H, CH2Ph), 7.15 (s,
1H, 5-H(pyridinone)), 7.30 (m, 5H, Ar ); MS (FAB) m/z, 315
[(M - Cl)+].
1,6-Dim e t h yl-2-(N -isob u t yr yla m in om e t h yl)-3-b e n z-
yloxyp yr id in -4(1H)-on e h yd r och lor id e (17c): (62%); mp
174-176 °C; 1H NMR (DMSO-d6) δ 0.85 (d, 6H, COCH(CH3)2),
1.95-2.30 (m, 1H, COCH(CH3)2), 2.50 (s, 3H, 6-CH3), 3.75 (s,
3H, N-CH3), 4.30 (br, 2H, CH2NH), 5.05 (s, 2H, CH2Ph), 7.05
(s, 1H, 5-H(pyridinone)), 7.15 (m, 5H, Ar ); MS (FAB) m/z, 329
[(M - Cl)+].
4.40 (d, 2H, CH2NHCO), 5.15 (s, 2H, CH2Ph), 6.30 (s, 1H,
5-H(pyridinone)), 6.50-7.30 (br., 2H, NH), 7.40 (m, 5H, Ar );
MS (FAB) m/z, 371 [M+].
An analogous procedure starting with 20b gave 1,6-Di-
m et h yl-2-(4′-N-n -p r op ylsu ccin a m id o)m et h yl-3-b en zyl-
oxyp yr id in -4(1H)-on e (21b): (100%): mp 124-127 °C; 1H
NMR (CDCl3) δ 0.88 (t, 3H, CH3CH2CH2NH), 1.10-1.80 (m,
2H, CH3CH2CH2NH), 2.25 (s, 3H, 6-CH3), 2.50 (s, 4H, CH2CH2-
CONH), 2.85-3.40 (m, 2H, CH3CH2CH2NH), 3.40 (s, 3H,
N-CH3), 4.40 (d, 2H, CH2NHCO), 5.10 (s, 2H, CH2Ph), 6.25
(s, 1H, 5-H(pyridinone)), 6.50 (t, 1H, NH), 7.05 (t, 1H, NH),
7.35 (m, 5H, Ar ); MS (FAB) m/z, 399 [M+].
Analogous hydrogenation procedures to the preparation of
12 starting with 17a -c gave compounds 18a -c.
1,6-Dim eth yl-2-(3′-a ceta m id op r op ion a m id o)m eth yl-3-
h yd r oxyp yr id in -4(1H)-on e Hyd r och lor id e (22a ). A solu-
tion of 21a (1.39 g, 3.75 mmol) in ethanol (50 mL) was
subjected to hydrogenolysis in the presence of 5% Pd/C catalyst
(0.3 g) for 3 h. The catalyst was removed by filtration, and
the filtrate was acidified to pH 1 with concentrated hydro-
chloric acid. After removal of the solvent in vacuo, the residue
was purified by recrystallization from methanol/diethyl ether
to give a white solid (1.07 g, 90%): mp 198-200 °C; 1H NMR
(DMSO-d6) δ 1.70 (s, 3H, CH3CO), 2.20 (t, 2H, COCH2CH2-
NH), 2.50 (s, 3H, 6-CH3), 2.90-3.50 (m, 2H, COCH2CH2NH),
3.80 (s, 3H, N-CH3), 4.55 (d, 2H, CH2NHCO), 7.30 (s, 1H,
5-H(pyridinone)), 7.90 (t, 1H, NH), 8.80 (t, 1H, NH); MS (FAB)
m/z, 282 [(M - Cl)+]. Anal. (C13H20N3O4Cl) C, H, N.
1,6-Dim eth yl-2-(N-a cetyla m in om eth yl)-3-h yd r oxyp yr i-
d in -4(1H)-on e h yd r och lor id e (18a ): mp 236-238 °C; 1H
NMR (DMSO-d6) δ 1.85 (s, 3H, COCH3), 2.55 (s, 3H, 6-CH3),
3.90 (s, 3H, N-CH3), 4.60 (br, 2H, CH2NH), 7.20 (s, 1H, 5-H
(pyridinone)), 8.70 (t, 1H, NHCO); MS (FAB) m/z, 211 [(M -
Cl)+]. Anal. (C10H15N2O3Cl) C, H, N.
1,6-Dim eth yl-2-(N-p r op ion yla m in om eth yl)-3-h yd r oxy-
p yr id in -4(1H)-on e h yd r och lor id e (18b): mp 245-257 °C;
1H NMR (DMSO-d6) δ 0.90 (t, 3H, COCH2CH3), 2.05 (q, 2H,
COCH2CH3), 2.45 (s, 3H, 6-CH3), 3.75 (s, 3H, N-CH3), 4.45
(br, 2H, CH2NH), 7.05 (s, 1H, 5-H(pyridinone)), 8.65 (t, 1H,
NHCO); MS (FAB) m/z, 225 [(M - Cl)+]. Anal. (C11H17N2O3-
Cl) C, H, N.
1,6-Dim eth yl-2-(N-isobu tyr yla m in om eth yl)-3-h yd r oxy-
p yr id in -4(1H)-on e h yd r och lor id e (18c): mp 243-245 °C;
1H NMR (DMSO-d6) δ 0.85 (d, 6H, COCH(CH3)2), 2.15-2.45
(m, 1H, COCH(CH3)2), 2.40 (s, 3H, 6-CH3), 3.70 (s, 3H, N-CH3),
4.45 (br, 2H, CH2NH), 6.95 (s, 1H, 5-H(pyridinone)), 8.70 (t,
1H, NHCO); MS (FAB) m/z, 239 [(M - Cl)+]. Anal. (C12H19N2O3-
Cl) C, H, N.
3-(3′-Acet a m id op r op ion yl)-1,3-t h ia zolid in e-2-t h ion e
(20a ). To a vigorously stirred solution of N-acetyl-â-alanine
(4.59 g, 35 mmol, 1 equiv) in dichloromethane (200 mL) was
added dicyclohexylcarbodiimide (DCCI) (7.93 g, 38.5 mmol, 1.1
equiv), followed by the addition of 2-mercaptothiazoline (4.58
g, 38.5 mmol, 1.1 equiv) and a catalytic amount of 4-(dimeth-
ylamino)pyridine (DMAP) (300 mg). The mixture was stirred
for 24 h, the white precipitate of N,N′-dicyclohexylurea (DCU)
filtered from the yellow solution, and the filtrate volume
adjusted to 400 mL with dichloromethane. The dichlo-
romethane layer was washed with 0.1 N sodium hydroxide
solution (3 × 150 mL) and water (200 mL), dried over
anhydrous sodium sulfate, filtered, and concentrated in vacuo
to yield the crude product as a yellow oil. Purification by
column chromatography on silica gel (eluant: methanol:
chloroform, 1:9 v/v) followed by recrystallization from chloroform/
petroleum ether 40-60 °C afforded a yellow crystalline solid
(7.80 g, 96%): mp 112-115 °C; 1H NMR (CDCl3) δ 2.0 (s, 3H,
CH3CO), 3.2-3.85 (m, 6H, COCH2CH2NH and CH2N), 4.60
(t, 2H, CH2S), 6.0-6.80 (br., 1H, NH); MS (FAB) m/z, 232 [M+].
Anal. (C8H12N2O2S2) C, H, N, S.
An analogous procedure starting with 21b gave 1,6-Di-
m eth yl-2-(4′-N-n -p r op ylsu ccin a m id o)m eth yl-3-h yd r oxy-
p yr id in -4(1H)-on e h yd r och lor id e (22b): (92%); mp 193-
1
195 °C; H NMR (DMSO-d6) δ 0.79 (t, 3H, CH3CH2CH2NH),
1.00-1.70 (m, 2H, CH3CH2CH2NH), 2.35 (s, 4H, CH2CH2-
CONH), 2.55 (s, 3H, 6-CH3), 2.70-3.20 (m, 2H, CH3CH2CH2-
NH), 3.90 (s, 3H, N-CH3), 4.60 (d, 2H, CH2NHCO), 7.4 (s, 1H,
5-H(pyridinone)), 7.90 (t, 1H, NH), 8.80 (t, 1H, NH), 7.10-
9.20 (br., OH ); MS (FAB) m/z, 310 [(M - Cl)+]. Anal.
(C15H24N3O4Cl) C, H, N.
Deter m in a tion of Distr ibu tion Coefficien ts. Distribu-
tion coefficients between 1-octanol and MOPS buffer (pH 7.4)
were determined using an automated continuous flow tech-
nique.11,14,15 The aqueous and octanol phases were presaturated
with respect to each other before use. The aqueous phase (50
mM MOPS buffer, pH 7.4) was separated from the two phase
system (1-octanol/MOPS buffer, pH 7.4) by means of a hydro-
philic cellulose filter (5 µm diameter, 589/3 Blauband filter
paper, Schleicher and Schuell) mounted in the gel-filtration
column adjuster. A known volume (25-50 mL) of MOPS buffer
(saturated with octanol) was taken in the flat base mixing
chamber. After a baseline was obtained, the solution was used
for reference absorbance. The ligand to be examined was
dissolved in buffer (saturated with octanol) so as to give an
absorbance of between 0.5 and 1.5 absorbance units at the
preselected wavelength (∼280 nm). The “online spectropho-
tometer” permitted continuous monitoring of the equilibrium
of the aqueous phase. Once a stable UV absorbance was
obtained, an aliquot of octanol was added and reequilibration
monitored. This cycle was repeated until a predefined total
volume of added octanol was reached. The distribution coef-
ficient (D7.4) was calculated for each octanol addition using the
following equation
An analogous procedure starting with N-n-propyl succi-
namic acid 19b gave 3-(N-n-propylsuccinamido)-1,3-thiazoli-
1
dine-2-thione (20b) (82%): mp 73-78 °C; H NMR (CDCl3) δ
0.95 (t, 3H, CH3CH2CH2NH), 1.15-1.80 (m, 2H, CH3CH2CH2-
NH), 2.55 (t, 2H, CH2CH2CONH), 3.0-3.85 (m, 6H, CH3-
CH2CH2NH, CH2CH2CONH and CH2N), 4.50 (t, 2H, CH2S),
5.30-6.30 (br., 1H, NH); MS (FAB) m/z, 260 [M+]. Anal.
(C10H16N2O2S2) C, H, N, S.
A0 - A1 Vw
D7.4
)
A1
Vo
1,6-Dim eth yl-2-(3′-a ceta m id op r op ion a m id o)m eth yl-3-
ben zyloxyp yr id in -4(1H)-on e (21a ). To a solution of 20a
(1.16 g, 5 mmol, 1 equiv) in dichloromethane (50 mL) was
added 16 (1.29 g, 5 mmol, 1 equiv), and the reaction mixture
was allowed to reflux for 6 h. The dichloromethane layer was
washed with 0.1 N sodium hydroxide solution (3 × 30 mL)
and water (30 mL) and dried over anhydrous sodium sulfate,
and the solvent was removed in vacuo. The crude product was
purified by column chromatography on silica gel (eluant:
methanol:chloroform, 15:85 v/v) to afford a white crystalline
where A0 ) initial absorbance of the aqueous phase, A1
)
absorbance at equilibrium of aqueous phase after the addition
of octanol, Vw ) volume of the aqueous (MOPS buffer), and Vo
) total volume of octanol after each addition.
Biologica l Meth od . (a ) Lip oxygen a se Assa y. Soybean
lipoxygenase (sbLPO) is a 5-lipoxygenase which catalyses the
peroxidation of its preferential substrate linoleic acid to linoleic
hydroperoxide. The inhibition of the enzyme was monitored
by the decrease in absorbance at 234 nm on conversion to the
product, linoleic hydroperoxide, relative to a control. The rate
of reaction in the absence and presence of various compounds
1
solid (1.76 g, 95%): mp 176-178 °C; H NMR (CDCl3) δ 2.0
(s, 3H, CH3CO), 2.30 (s, 3H, 6-CH3), 2.4 (t, 2H, COCH2CH2-
NH), 3.20-3.80 (m, 2H, COCH2CH2NH), 3.50 (s, 3H, N-CH3),