Group IVA and Group VIA Phospholipases
Journal of Medicinal Chemistry, 2006, Vol. 49, No. 9 2825
m, CH), 4.14 (1H, m, CH), 3.73 (3H, s, COOCH3), 2.77 (1H, m,
OH), 1.98-1.01 (32H, m, 16×CH2), 0.86 (6H, t, J ) 7 Hz,
2×CH3);13C NMR: δ 173.3, 166.7, 148.0, 120.5, 72.3, 51.6, 49.6,
37.0, 34.9, 34.0, 31.9, 29.7, 29.5, 29.3, 27.7, 25.0, 24.9, 22.7, 22.3,
14.1, 13.8; MS (ESI): m/z (%): 448 (100) [M + Na]+. Anal.
(C25H47NO4) C, H, N.
4-(2-Oxononadec-10-enoylamino)butyric Acid Methyl Ester
(4c). Yield 82%; oily solid; 1H NMR: δ 7.13 (1H, m, NHCOCO),
5.33 (2H, m, CHdCH), 3.67 (3H, s, CH3O), 3.33 (2H, m, CH2-
NH), 2.91 (2H, t, J ) 7.2 Hz, CH2COCO), 2.38 (2H, t, J ) 7.4
Hz, CH2COO), 1.98 (4H, m, 2×CH2CHdCH), 1.88 (2H, m, CH2-
CH2NH), 1.59 (2H, m, CH2CH2COCO), 1.26 (20H, br s, 10×CH2),
0.87 (3H, t, J ) 6.6 Hz, CH3); 13C NMR: δ 199.2, 173.3, 160.3,
129.9, 129.7, 51.7, 38.0, 36.7, 31.8, 31.3, 29.7, 29.6, 29.5, 29.3,
29.2, 29.0, 28.98, 27.2, 27.1, 24.3, 23.1, 22.6, 14.1; MS (FAB):
m/z (%): 410 (100) [Μ + H]+. Anal. (C24H43NO4) C, H, N.
4-(2-Oxohexadecanoylamino)oct-2-enoic Acid Methyl Ester
(11). Yield 81%, white solid; mp 48-50 °C; [R]D -19.7 (c 0.95,
Oxidation of 2-Hydroxyamides. Method A. To a solution of
2-hydroxyamide (5.00 mmol) in a mixture of toluene/EtOAc 1:1
(30 mL), a solution of NaBr (0.54 g, 5.25 mmol) in water (2.5
mL) was added followed by TEMPO (11 mg, 0.050 mmol). To
the resulting biphasic system, which was cooled at -5 °C, an
aqueous solution of 0.35 M NaOCl (15.7 mL, 5.50 mmol)
containing NaHCO3 (1.26 g, 15 mmol) was added dropwise under
vigorous stirring at -5 °C over a period of 1 h. After the mixture
had been stirred for a further 15 min at 0 °C, EtOAc (30 mL) and
H2O (10 mL) were added. The aqueous layer was separated and
washed with EtOAc (20 mL). The combined organic layers were
washed consecutively with 5% aqueous citric acid (30 mL)
containing KI (0.18 g), 10% aqueous Na2S2O3 (30 mL), and brine
and dried over Na2SO4. The solvents were evaporated under reduced
pressure, and the residue was purified by column chromatography
(EtOAc/petroleum ether (bp 40-60 °C), 1:9).
4-(2-Oxo-5-phenyl-pentanoylamino)butyric Acid Methyl Es-
ter (4a). Yield 67%; white solid; mp 30-31 °C; 1H NMR: δ 7.19-
7.15 (6H, m, C6H5, NHCO), 3.67 (3H, s, CH3O), 3.35 (2H, m,
CH2NH), 2.94 (2H, t, J ) 7.4 Hz, CH2COCO), 2.65 (2H, t, J )
7.8 Hz, CH2C6H5), 2.36 (2H, t, J ) 7.0 Hz, CH2COO), 1.91 (4H,
m, 2×CH2); 13C NMR: δ 198.7, 173.2, 160.0, 141.1, 128.3, 128.2,
125.8, 51.6, 38.5, 35.9, 34.8, 31.1, 24.6, 24.1; MS (ESI): m/z (%):
314 (63) [M + Na]+. Anal. (C16H21NO4) C, H, N.
1
CHCl3); Η NMR: δ 6.93 (1H, d, J ) 8 Hz, NHCOCO), 6.85
(1H, dd, J1 ) 6 Hz, J2 ) 16 Hz, CHCH)CH), 5.87 (1H, d, J ) 16
Hz, CHdCHCOOCH3), 4.58 (1H, m, CH), 3.73 (3H, s, COOCH3),
2.91 (2H, t, J ) 7 Hz, CH2COCO), 1.61 (4H, m, 2×CH2), 1.30
(26H, m, 13×CH2), 0.88 (6H, t, J ) 7 Hz, 2×CH3); 13C NMR: δ
199.3, 166.7, 159.8, 146.9, 121.4, 51.9, 50.4, 37.0, 34.1, 32.1, 29.9,
29.8, 29.6, 29.5, 29.3, 27.9, 23.4, 22.9, 22.5, 14.3, 14.0; MS (ESI):
m/z (%): 446 (85) [M + Na]+. Anal. (C25H45NO4) C, H, N.
4-(2-Oxohexadecanoylamino)oct-2-enoic Acid (10). The pro-
cedure is the same as that followed in method B except that the
organic layer was not washed with 10% aqueous NaHCO3. Yield
1
69%, white solid; mp 65-67 °C; [R]D -7.7 (c 0.84, CHCl3); Η
NMR: δ 7.0 (1H, m, NHCOCO), 6.82 (1H, dd, J1 ) 6 Hz, J2 )
16 Hz, CHCHdCH), 5.87 (1H, d, J ) 16 Hz, CHdCHCOOCH3),
4.62 (1H, m, CH), 2.91 (2H, t, J ) 7 Hz, CH2COCO), 1.61 (4H,
m, 2×CH2), 1.44-1.25 (26H, m, 13×CH2), 0.88 (6H, t, J ) 7 Hz,
2×CH3); 13C NMR: δ 199.0, 170.8, 159.6, 149.0, 120.8, 50.2, 36.7,
33.7, 31.9, 29.6, 29.4, 29.3, 29.0, 27.7, 23.1, 22.7, 22.3, 14.1, 13.8;
MS (ESI): m/z (%): 408 (100) [M - H]-. Anal. (C24H43NO4) C,
H, N.
4-(2-Oxo-6-phenyl-hexanoylamino)butyric Acid Methyl Ester
1
(4b). Yield 75%; white solid; mp 52-54 °C; H NMR: δ 7.29-
Saponification of Methyl Esters. To a stirred solution of a
methyl ester (2.00 mmol) in a mixture of dioxane/H2O (9:1, 20
mL), 1 N NaOH (2.2 mL, 2.2 mmol) was added, and the mixture
was stirred for 12 h at room temperature. The organic solvent was
evaporated under reduced pressure, and H2O (10 mL) was added.
The aqueous layer was washed with EtOAc, acidified with 1 N
HCl, and extracted with EtOAc (3 × 12 mL). The combined organic
layers were washed with brine, dried over Na2SO4, and evaporated
under reduced pressure. The residue was purified after recrystal-
lization (EtOAc/petroleum ether (bp 40-60 °C)).
4-(2-Hydroxy-5-phenylpentanoylamino)butyric Acid (3a). Yield
79%; white solid; mp 63-65 °C; 1H NMR: δ 7.26-7.12 (6H, m,
C6H5, NHCO), 4.09 (1H, m, CH), 3.27 (2H, m, CH2NH), 2.59 (2H,
t, J ) 6.6 Hz, CH2C6H5), 2.31 (2H, t, J ) 6.6 Hz, CH2COOH),
1.78 (6H, m, 3×CH2); 13C NMR: δ 177.3, 175.5, 142.0, 128.3,
125.8, 71.8, 38.4, 35.5, 34.1, 31.3, 26.8, 24.3. Anal. (C15H21NO4)
C, H, N.
4-(2-Hydroxy-6-phenylhexanoylamino)butyric Acid (3b). Yield
86%; white solid; mp 78-80 °C; 1H NMR: δ 7.30-7.13 (6H, m,
C6H5, NHCO), 4.11 (1H, m, CH), 3.30 (2H, m, CH2NH), 2.60 (2H,
t, J ) 7.8 Hz, CH2C6H5), 2.35 (2H, t, J ) 6.6 Hz, CH2COOH),
1.81-1.47 (8H, m, 4×CH2); 13C NMR: δ 177.4, 175.5, 142.4,
128.3, 128.2, 125.7, 71.9, 38.4, 35.7, 34.3, 31.4, 31.1, 24.7, 24.4;
MS (ESI): m/z (%): 316 (54) [M + Na]+, 294 (100) [M + H]+.
Anal. (C16H23NO4) C, H, N.
4-(2-Hydroxyhexadecanoylamino)oct-2-enoic Acid (8). Yield
62%; white solid; mp 46-48 °C; 1H NMR: δ 6.92 (1H, m, NHCO),
6.76 (1H, dd, J1 ) 6 Hz, J2 ) 16 Hz, CHCH dCH), 5.87 (1H, d,
J ) 16 Hz, CHdCHCOOH), 4.64 (1H, m, CH), 4.20 (1H, m, CH),
3.42 (1H, br, OH), 1.95-1.25 (32H, m, 16xCH2), 0.88 (6H, t, J )
7 Hz, 2×CH3);13C NMR: δ 172.3, 170.5, 150.0, 120.5, 72.6, 49.9,
35.1, 34.2, 32.1, 29.9, 29.6, 28.0, 25.3, 22.9, 22.7, 22.5, 14.3, 14.1;
MS (ESI): m/z (%): 434 (100) [M + Na]+. Anal. (C24H45NO4) C,
H, N.
7.16 (6H, m, C6H5, NHCO), 3.69 (3H, s, CH3O), 3.37 (2H, m,
CH2NH), 2.95 (2H, t, J ) 7.0 Hz, CH2COCO), 2.64 (2H, t, J )
7.0 Hz, CH2C6H5), 2.38 (2H, t, J ) 7.0 Hz, CH2COO), 1.89-1.66
(6H, m, 3×CH2); 13C NMR: δ 198.8, 173.2, 160.1, 141.9, 128.21,
128.15, 125.6, 51.6, 38.5, 36.4, 35.4, 31.1, 30.6, 24.2, 22.6; MS
(ESI): m/z (%): 328 (75) [M + Na]+. Anal. (C17H23NO4) C, H,
N.
4-(2-Oxo-5-phenyl-pentanoylamino)butyric Acid (5a). The
procedure is the same as that followed in method A, which is
described above, except that in this case the aqueous layer was
acidified before the workup and then extracted with EtOAc, and
the combined organic layers were washed with 5% aqueous citric
acid containing KI and 10% aqueous Na2S2O3 (30 mL). The residue
was purified by column chromatography (EtOAc/petroleum ether
(bp 40-60 °C)). Yield 48%; white solid; mp 65-67 °C; 1Η
NMR: δ 7.25-7.11 (6H, m, C6H5, NHCOCO), 3.33 (2H, m, CH2-
NH), 2.86 (2H, t, J ) 7.4 Hz, CH2COCO), 2.60 (2H, m, CH2),
2.36 (2H, m, CH2), 1.86 (4H, m, 2×CH2); 13C NMR: δ 198.8,
178.5, 160.3, 141.2, 128.41, 128.37, 126.0, 38.5, 36.1, 34.9, 31.2,
24.7, 24.0; MS (ESI): m/z (%): 276 (100) [Μ - H]-. Anal. (C15H19-
NO4) C, H, N.
4-(2-Oxo-6-phenyl-hexanoylamino)-butyric Acid (5b). The
procedure is the same as that followed for 5a. Yield 47%; white
solid; mp 60-62 °C; 1Η NMR: δ 7.27-7.15 (6H, m, C6H5,
NHCOCO), 3.35 (2H, m, CH2NH), 2.94 (2H, t, J ) 7.4 Hz, CH2-
COCO), 2.60 (2H, m, CH2), 2.38 (2H, m, CH2), 1.86 (2H, m, CH2),
1.64 (4H, m, 2×CH2); 13C NMR: δ 198.8, 178.8, 160.3, 142.0,
128.33, 128.27, 125.7, 38.6, 36.5, 35.5, 31.4, 30.7, 24.2, 22.6; MS
(FAB): m/z (%): 292 (100) [Μ + H]+. Anal. (C16H21NO4) C, H,
N.
Oxidation of 2-Hydroxyamides. Method B. To a solution of
2-hydroxyamide (1 mmol) in dry CH2Cl2 (20 mL), Dess-Martin
periodinane was added (0.64 g, 1.5 mmol), and the mixture was
stirred for 2 h at room temperature. The organic solution was
washed with 10% aqueous NaHCO3 and dried over Na2SO4, and
the organic solvent was evaporated under reduced pressure. The
residue was purified by recrystallization (EtOAc/petroleum ether
(bp 40-60 °C)).
Inhibitor 12 was prepared by following procedures similar to
those described above.
4-(2-Oxononadec-10-enoylamino)butyric Acid (12). Yield
69%; white solid; mp 57-59 °C; 1Η NMR: δ 10.05 (1H, br,
COOH), 7.23 (1H, m, NHCOCO), 5.33 (2H, m, CHdCH), 3.38