1002 J ournal of Natural Products, 2004, Vol. 67, No. 6
Abe et al.
(C-4), 21.2 (C-5); HRESIMS m/z 349.1035 [M + Na]+ (calcd
for C13H19N4NaO4P, 349.1042).
12% yield. To prepare analytical specimens of 5b and 6b, each
optically pure (R)-(+)-1-phenylethylamine salt, which was
purified in the next step, was changed into the sodium salt
with sodium hydrogen carbonate and then purified by Diaion
HP-20SS column chromatography (water-30% MeOH/water).
The physicochemical data were obtained by using each result-
ant specimen.
(3S,RP )-1-Am in o(su lfoa m in o)p h osp h in yl-3-ben zyloxy-
ca r bon yla m in o-2-p ip er id in on e Sod iu m Sa lt (5a ) a n d
(3S,SP )-1-Am in o(su lfoa m in o)p h osp h in yl-3-ben zyloxyca r -
bon yla m in o-2-p ip er id in on e Sod iu m Sa lt (6a ). To a solu-
tion of compound 4a (5.00 g, 15.3 mmol) in DMF (40 mL, dried
with molecular sieves 4 Å) was added SO3‚pyridine complex
(3.17 g, 19.9 mmol) at 0 °C, and the mixture was stirred for 2
h at 6-8 °C. To the mixture were added water (50 mL) and
NaHCO3 (3.22 g, 38.3 mmol), and the mixture was stirred for
5 min at room temperature. The reaction mixture was diluted
with water (200 mL) and was applied to a Diaion HP-20SS
(500 mL) column. The column was washed with water (1000
mL) and then was eluted with water-30% MeOH/water at
room temperature. The eluate was monitored by UV (254 nm)
and was collected so that the weight of each fraction was
15 g. Each UV absorbing fraction was analyzed by reversed-
phase HPLC. The desired compounds were collected in the
fractions of 20-25% MeOH/water, and compound 6a eluted
slightly earlier than 5a . The absorbing fractions were roughly
divided into eight fraction groups based on the ratio of the
diastereomer; the ratio (6a :5a ) of each fraction group was
about >20:1, 10:1, 4:1, 2:1, 1:2, 1:4, 1:10, and 1:>20, respec-
tively. Each fraction group except the groups of >20:1 and
1:>20 was applied to Diaion HP-20SS column chromatography
again, and each fraction was divided as mentioned above.
Then, the fraction groups of analogous diastereomer ratio were
combined and applied to column chromatography again. This
procedure was repeated until sufficient amounts of concen-
trated diastereomer fractions were obtained. Evaporation of
the fraction groups of >20:1 and 1:>20 under reduced pressure
gave diastereomers 5a and 6a of >90% de, respectively: 5a
(0.80 g, 12% yield) and 6a (1.04 g, 16% yield). To prepare
analytical specimens of 5a and 6a , each optically pure (S)-(-
)-1-phenylethylamine salt, which was purified in the next step,
was changed into the sodium salt with sodium hydrogen
carbonate and then purified by Diaion HP-20SS column
chromatography (water-30% MeOH/water). The physicochem-
ical data were obtained by using each resultant specimen.
P h ysicoch em ica l d a ta of 5b: [R]23 -25.3° (c 0.5, H2O);
D
IR (KBr) νmax 3408, 3294, 1705, 1248, 1057 cm-1
;
1H NMR
(D2O, 400 MHz) δ 7.38-7.48 (5H, m, Ph), 5.12-5.17 (2H, m,
OCH2Ph), 4.20 (1H, m, H-3), 3.71 (1H, m, H-6a), 3.59 (1H, m,
H-6b), 2.19 (1H, m, H-4a), 1.77-2.03 (3H, m, H-4b and H-5);
13C NMR (D2O, 100 MHz) δ 178.6 (C-2), 160.8 (NHCOO), 139.3
(Ph), 131.7 (Ph×2), 131.3 (Ph), 130.7 (Ph×2), 70.1 (OCH2Ph),
55.1 (C-3), 48.1 (C-6), 29.2 (C-4), 24.0 (C-5); HRESIMS m/z
451.0428 [M + Na]+ (calcd for C13H18N4Na2O7PS, 451.0429);
reversed-phase HPLC analysis, retention time 12.7 min (con-
ditions were similar to those described for compound 5a ).
P h ysicoch em ica l d a ta of 6b: [R]23 +63.3° (c 0.5, H2O);
D
IR (KBr) νmax 3384, 3303, 1720, 1647, 1217, 1039 cm-1
;
1H
NMR (D2O, 400 MHz) δ 7.39-7.49 (5H, m, Ph), 5.11-5.21 (2H,
m, OCH2Ph), 4.24 (1H, dd, J ) 11.2, 6.8 Hz, H-3), 3.78 (1H,
m, H-6a), 3.58 (1H, m, H-6b), 2.17 (1H, m, H-4a), 1.98 (1H, m,
H-5a), 1.86 (1H, m, H-5b), 1.73 (1H, tdd, J ) 12.2, 8.8, 6.8 Hz,
H-4b); 13C NMR (D2O, 100 MHz) δ 178.0 (C-2), 161.0 (NH-
COO), 139.3 (Ph), 131.7 (Ph×2), 131.3 (Ph), 130.6 (Ph×2), 70.0
(OCH2Ph), 54.9 (C-3), 47.2 (C-6), 28.8 (C-4), 23.4 (C-5);
HRESIMS m/z 451.0413 [M + Na]+ (calcd for C13H18N4Na2O7-
PS, 451.0429); reversed-phase HPLC analysis, retention time
14.0 min (conditions were similar to those described for
compound 5a ).
(3S,RP )-3-Am in o-1-a m in o(su lfoa m in o)p h osp h in yl-2-p i-
p er id in on e (7a ). A mixture of (S)-(-)-1-phenylethylamine
hydrochloride (0.40 g, 2.53 mmol) and compound 5a (90% de,
0.80 g, 1.87 mmol) in water (4.0 mL) was applied to a Diaion
HP-20SS (200 mL) column. The column was eluted with
water-70% MeOH/water at room temperature, and the (S)-
(-)-1-phenylethylamine salt of 5a was collected in the fractions
of 45-60% MeOH/water. The fractions including the am-
monium salt of 5a were combined and then evaporated under
reduced pressure. The residue was applied to a Diaion HP-
20SS (200 mL) column once more. After evaporation of the
fractions under reduced pressure, the residue was dissolved
in MeOH (10 mL) and was divided into 6 portions. Each
portion was applied to a Sephadex LH-20 (200 mL) column,
which was developed with MeOH. Then, the fractions of
insufficient optical purity were combined and repeatedly
subjected to similar column chromatography. The delayed
fractions containing pure material (>99% de) were combined
and evaporated under reduced pressure to give the optically
pure (S)-(-)-1-phenylethylamine salt of 5a (0.88 g).19 To a
solution of the (S)-(-)-1-phenylethylamine salt of 5a (0.88 g,
1.67 mmol) in MeOH (18.0 mL) and water (2.0 mL) was added
Pd-black (0.18 g), and the suspension was stirred for 10 h at
room temperature under hydrogen atmosphere. After the Pd-
black was removed by filtration, the filtrate was evaporated
under reduced pressure to afford a residue, which was purified
by Diaion HP-20SS column chromatography (water). The solid
residue was recrystallized from water/EtOH to give 7a (0.35
P h ysicoch em ica l d a ta of 5a : [R]23 -65.5° (c 1.0, H2O);
D
IR (KBr) νmax 3386, 3303, 1726, 1647, 1219, 1059 cm-1
;
1H
NMR (D2O, 400 MHz) δ 7.39-7.48 (5H, m, Ph), 5.12-5.21 (2H,
m, OCH2Ph), 4.32 (1H, dd, J ) 11.2, 6.8 Hz, H-3), 3.75 (1H,
m, H-6a), 3.61 (1H, m, H-6b), 2.20 (1H, m, H-4a), 2.02 (1H, m,
H-5a), 1.90 (1H, m, H-5b), 1.76 (1H, tdd, J ) 11.7, 9.3, 6.8 Hz,
H-4b); 13C NMR (D2O, 100 MHz) δ 178.6 (C-2), 161.1
(NHCOO), 139.2 (Ph), 131.7 (Ph×2), 131.3 (Ph), 130.6 (Ph×2),
70.0 (OCH2Ph), 54.8 (C-3), 47.4 (C-6), 28.5 (C-4), 23.3 (C-5);
HRESIMS m/z 451.0427 [M + Na]+ (calcd for C13H18N4Na2O7-
PS, 451.0429); reversed-phase HPLC analysis, retention time
14.0 min (conditions: column, Senshu Pak PEGASIL ODS
(4.6×250 mm); column temperature, 40 °C; eluent, 0.1%
trifluoroacetic acid(aq)/MeOH, 70:30; flow rate, 1.0 mL/min;
detection, UV 205 nm).
P h ysicoch em ica l d a ta of 6a : [R]23 +27.0° (c 1.0, H2O);
D
IR (KBr) νmax 3404, 3323, 1705, 1246, 1057 cm-1
;
1H NMR
(D2O, 400 MHz) δ 7.39-7.48 (5H, m, Ph), 5.12-5.17 (2H, m,
OCH2Ph), 4.20 (1H, m, H-3), 3.72 (1H, m, H-6a), 3.59 (1H, m,
H-6b), 2.18 (1H, m, H-4a), 1.75-2.00 (3H, m, H-4b and H-5);
13C NMR (D2O, 100 MHz) δ 178.5 (C-2), 160.8 (NHCOO), 139.2
(Ph), 131.7 (Ph×2), 131.3 (Ph), 130.6 (Ph×2), 70.0 (OCH2Ph),
55.0 (C-3), 48.0 (C-6), 29.1 (C-4), 23.9 (C-5); HRESIMS m/z
451.0432 [M + Na]+ (calcd for C13H18N4Na2O7PS, 451.0429);
reversed-phase HPLC analysis, retention time 12.6 min (con-
ditions were similar to those described for compound 5a ).
(3R,RP )-1-Am in o(su lfoa m in o)p h osp h in yl-3-ben zyloxy-
ca r bon yla m in o-2-p ip er id in on e Sod iu m Sa lt (5b) a n d
(3R,SP )-1-Am in o(su lfoa m in o)p h osph in yl-3-ben zyloxyca r -
bon yla m in o-2-p ip er id in on e Sod iu m Sa lt (6b). The syn-
thetic method was similar to that noted for compounds 5a and
6a . Compound 4b (1.20 g, 3.68 mmol) was treated with SO3‚
pyridine complex (1.17 g, 7.35 mmol), followed by NaHCO3
(0.77 g, 7.35 mmol), and the resultant diastereomer was
separated to give 5b (0.176 g) in 11% yield and 6b (0.195 g) in
g) in 65% yield: mp 203-208 °C (dec); [R]23 -21.5° (c 1.0,
D
H2O); IR (KBr) νmax 3510, 3355, 3250, 1658, 1545, 1308, 1188
1
cm-1; H NMR (D2O, 500 MHz) δ 4.18 (1H, dd, J ) 12.0, 6.8
Hz, H-3), 3.82 (1H, tdd, J ) 5.1, 13.0, 7.3 Hz, H-6a), 3.70 (1H,
tdd, J ) 5.1, 13.0, 6.7 Hz, H-6b), 2.42 (1H, m, H-4a), 2.14 (1H,
m, H-5a), 1.89-2.03 (2H, m, H-4b and H-5b); 13C NMR (D2O,
125 MHz) δ 172.4 (C-2), 51.3 (C-3), 45.4 (C-6), 24.2 (C-4), 20.5
(C-5); 31P NMR (D2O, 202 MHz) δ 6.03; HRESIMS m/z
271.0278 [M - H]- (calcd for C5H12N4O5PS, 271.0266); anal.
C 20.41%, H 4.96%, N 19.44%, calcd for C5H13N4O5PS‚H2O, C
20.69%, H 5.21%, N 19.30%.
(3S,SP )-3-Am in o-1-a m in o(su lfoa m in o)p h osp h in yl-2-p i-
p er id in on e (8a ). The synthetic method was similar to that
described for compound 7a . A mixture of (S)-(-)-1-phenylethyl-
amine hydrochloride (0.58 g, 3.68 mmol) and compound 6a
(90% de, 1.04 g, 2.43 mmol) was purified to give the optically