Kasumigamide
J . Org. Chem., Vol. 65, No. 19, 2000 5899
Ta ble 1. 1H a n d 13C NMR Da ta for Ka su m iga m id e in
To determine the stereochemistry of â-phenylserine, 1
was hydrolyzed with 6 N HCl, and â-phenylserine was
purified by reversed-phase HPLC. The HPLC analysis
indicated that â-phenylserine in 1 was either erythro-â-
phenyl-D- or -L-serine.8 The negative optical rotation
value8 of â-phenylserine in 1 revealed that this hydroxy
amino acid is erythro-â-phenyl-D-serine. Furthermore, the
HPLC analysis of Marfey derivatives of four stereoiso-
mers also supported that â-phenylserine in 1 is erythro-
â-phenyl-D-serine.9 To determine the stereochemistry of
Ahipa, four stereoisomers were synthesized from Boc Trp
(For) as previously described by Maibaum et al.10 Boc Trp
(For) was activated by N,N′-carbonyldiimidazole followed
by the treatment with magnesium enolate of hydrogen
DMSO-d 6
13C
1H (mult J (Hz))
HMBC (C no.)
Phenyllactic Acid
1
2
173.2
72.1 4.01 (dd, 8.5, 3.9)
40.3 2.65 (dd, 13.8, 8.5)
2.95 (dd, 13.8, 3.9)
138.6
129.4 7.18 (d, 8.1, 2H)
127.9 7.23 (dd, 8.1, 7.7, 2H)
125.9 7.17 (t, 7.7)
5.55 (br)
1, 3
1, 2, 4, 5, 9
1, 2, 4, 5, 9
3a
3b
4
5,9
6,8
7
3, 5, 7, 9
4, 5, 6, 8, 9
5, 9
2-OH
â-Ala
170.3
35.3 2.10 (ddd, 14.5, 7.5, 7.1)
2.21 (ddd, 14.5, 7.5, 7.1)
35.0 3.17 (m, 2H)
7.75 (t, 5.0)
10
11a
11b
12
10, 12
10, 12
1, 10, 11
1, 10, 12
(7) Shin, H. J .; Matsuda, H.; Murakami, M.; Yamaguchi, K. J . Org.
Chem. 1997, 62, 1810-1813.
N-1
(8) erythro-â-Phenyl-D,L-serine was prepared from threo-â-phenyl-
D,L-serine. (a) Bolhofer, W. A. J . Am. Chem. Soc. 1952, 74, 5459-5461.
(b) Fones, W. S. J . Biol. Chem. 1953, 204, 323-328. For experimental
details of the synthetic procedures, see Supporting Information.
â-Phenylserine was analyzed by reversed-phase HPLC (Cosmosil 5C18-
MS, 4.6 × 250 mm; 2% MeCN containing 0.05% TFA; UV detection
210 nm; flow rate 1.0 mL/min). Retention times (min) in standards:
erythro-â-phenyl-D,L-serine (8.0) and threo-â-phenyl-D,L-serine (9.8).
Retention time (min) in â-phenylserine of 1: (8.0). Natural â-phen-
ylserine: [R]25 - 79.7° (c 0.12, 6 N HCl) [lit.8b [R]25 (2% solution in
4-Amino-3-hydroxy-5-indolylpentanoic Acid
171.2
13
14a
14b
15
40.0 2.28 (dd, 14.4, 3.7)
2.35 (dd, 14.4, 9.1)
70.1 3.84 (ddd, 9.1, 6.4, 3.7)
54.0 3.90 (dddd, 9.2, 9.0, 6.4, 3.5)
25.0 2.72 (dd, 15.0, 9.2)
3.06 (dd, 15.0, 3.5)
122.9 7.06 (s)
13, 15
16
17a
17b
18
15, 18, 19, 20
15, 18, 19, 20
17, 19, 20, 25
D
D
19
111.4
6 N HCl) threo-â-phenyl-L-serine, - 48.6°; threo-â-phenyl-D-serine, +
48.0°; erythro-â-phenyl-L-serine, + 81.3°; erythro-â-phenyl-D-serine, -
82.0°].
20
127.6
21
118.3 7.53 (d, 7.7)
118.0 6.95 (dd, 7.7, 7.3)
120.7 7.03 (dd, 7.7, 7.3)
111.2 7.31 (d, 7.7)
136.1
19, 23, 25
20, 24
22
(9) For experimental details of the synthetic procedures, see Sup-
porting Information. â-Phenylserine was derivatized with L-Marfey’s
reagent and analyzed by reversed-phase HPLC (Cosmosil 5C18-MS,
4.6 × 250 mm; 35% MeCN containing 0.1% TFA; UV detection 340
nm; flow rate 1.0 mL/min). Retention times in the derivatives of the
standards (min): erythro-â-phenyl-L-serine (14.8), threo-â-phenyl-L-
serine (15.6), erythro-â-phenyl-D-serine (19.2), threo-â-phenyl-D-serine
(24.8). Retention time in the derivatives of â-phenylserine of 1 (min):
(19.2).
23
21, 25
24
20, 22
25
N-2
N-3
15-OH
7.75 (d, 9.0)
10, 16
18, 19, 25
10.70 (s)
5.04 (br)
Arginine
171.4
51.8 4.31 (ddd, 8.5, 7.8, 5.6)
29.2 1.40 (m)
1.56 (m)
26
27
28a
28b
29
30
31
N-4
N-5
(10) Maibaum, J .; Rich, D. H. J . Org. Chem. 1988, 53, 869-873.
For experimental details of the synthetic procedures, see Supporting
Information.
26, 28, 29
29
29
(11) Otani, I.; Kusumi, T.; Kashman, Y.; Kakisawa, H. J . Am. Chem.
Soc. 1991, 113, 4092-4096.
24.8 1.36 (m, 2H)
40.3 3.01 (m, 2H)
156.6
(12) Ahipa from 1 (100 µg) was derivatized with L-FDAA6 and
analyzed by reversed-phase HPLC (Cosmosil 5C18-MS, 4.6 × 250 mm,
20-60% (1%/min) MeCN containing 0.05% TFA, UV detection 340 nm,
flow rate 1.0 mL/min). Retention times (min) of standards: (3R,4S)-
Ahipa (28.8), (3S,4S)-Ahipa (29.4), (3S,4R)-Ahipa (30.6), (3R,4R)-Ahipa
(32.0), derivative from 1 (30.6).
28, 29, 31
13, 26, 27
7.94 (d, 8.5)
7.45 (t, 5.4)
â-Phenylserine
171.4
58.4 4.47 (dd, 8.8, 7.3)
72.7 4.86 (d, 7.3)
141.8
32
(13) (3R,4S)-4-Amino-3-hydroxy-5-indolylpentanoic acid: [R]23D -26.7°
(c 0.2, 50% MeOH); HRFABMS m/z 249.1238 [M + H]+ (C13H17N2O3,
∆ - 0.1 mmu); 1H NMR (DMSO-d6, 600 MHz) δ 2.37 (dd, 15.4, 6.0,
1H, COCH2), 2.41 (dd, 15.4, 5.1, 1H, COCH2), 2.74 (dd, 14.5, 8.1, 1H,
CH2Ar), 3.02 (dd, 14.5, 5.1, 1H, CH2Ar), 3.15 (br, 1H, CH), 3.72 (m,
1H, CHOH), 6.98 (t, 8.1, 1H, ind.), 7.06 (t, 8.1, 1H, ind.), 7.20 (s, 1H,
ind.), 7.32 (d, 8.1, 1H, ind.), 7.54 (d, 8.1, 1H, ind.), 10.88 (s, 1H, NH).
33
26, 32, 34, 35
32, 33, 35, 36, 40
34
35
36,40
37,39
38
126.6 7.37 (d, 7.7, 2H)
127.7 7.29 (t, 7.7, 2H)
127.2 7.22 (t, 7.7)
7.99 (d, 8.8)
34, 36, 38, 40
35, 37, 39
36, 40
(3S,4S)-4-Amino-3-hydroxy-5-indolylpentanoic acid: [R]23 -14.4° (c
N-6
34-OH
26
D
5.76 (br)
0.1, 50% MeOH); HRFABMS m/z 249.1249 [M + H]+ (C13H17N2O3, ∆
+ 1.0 mmu); 1H NMR (DMSO-d6, 600 MHz) δ 2.26 (dd, 15.8, 4.7, 1H,
COCH2), 2.39 (dd, 15.8, 5.6, 1H, COCH2), 2.77 (dd, 14.5, 6.8, 1H, CH2-
Ar), 2.96 (dd, 14.5, 7.3, 1H, CH2Ar), 3.09 (m, 1H, CH), 3.73 (br, 1H,
CHOH), 6.98 (t, 8.1, 1H, ind.), 7.06 (t, 8.1, 1H, ind.), 7.18 (s, 1H, ind.),
7.32 (d, 8.1, 1H, ind.), 7.54 (d, 8.1, 1H, ind.), 10.87 (s, 1H, NH). (3S,4R)-
4-Amino-3-hydroxy-5-indolylpentanoic acid: [R]23D + 28.4° (c 0.1, 50%
MeOH); HRFABMS m/z 249.1232 [M + H]+ (C13H17N2O3, ∆ - 0.7
mmu); 1H NMR (DMSO-d6, 600 MHz) δ 2.37 (dd, 15.4, 6.0, 1H, COCH2),
2.40 (dd, 15.4, 5.0, 1H, COCH2), 2.73 (dd, 14.5, 8.6, 1H, CH2Ar), 3.02
(dd, 14.5, 5.1, 1H, CH2Ar), 3.14 (m, 1H, CH), 3.70 (m, 1H, CHOH),
6.98 (t, 8.1, 1H, ind.), 7.06 (t, 8.1, 1H, ind.), 7.19 (s, 1H, ind.), 7.32 (d,
8.1, 1H, ind.), 7.54 (d, 8.1, 1H, ind.), 10.88 (s, 1H, NH). (3R,4R)-4-
and the ROESY correlation (H-15/H-17) connected C-15
with C-16. These results and the HMBC correlations
between H-14/C-13 (δ 171.2) and H-17/C-18 and C-20
revealed the structure of the 4-amino-3-hydroxy-5-in-
dolylpentanoic acid (Ahipa) unit.
The sequence of these five units was determined by
the HMBC correlations between â-Ala H-12 and 1-NH/
Pla C-1, Ahipa H-16 and 2-NH/â-Ala C-10, Arg 4-NH/
Ahipa C-13, and â-phenylserine H-33 and 6-NH/Arg
C-26).
The stereochemistry of Arg was determined as D by
the HPLC analysis of the derivatives of the acid hydroly-
sate of 1 with L-Marfey’s reagent.6 The stereochemistry
of Pla was determined to be D by the HPLC analysis of
menthyl ester derivative of the acid hydrolysate of 1.7
Amino-3-hydroxy-5-indolylpentanoic acid: [R]23 + 18.3° (c 0.1, 50%
D
MeOH); HRFABMS m/z 249.1245 [M + H]+ (C13H17N2O3, ∆ + 0.6
mmu), 1H NMR (DMSO-d6, 600 MHz) δ 2.25 (dd, 15.8, 4.7, 1H, COCH2),
2.38 (dd, 15.8, 5.6, 1H, COCH2), 2.77 (dd, 14.1, 6.8, 1H, CH2Ar), 2.95
(dd, 14.1, 7.3, 1H, CH2Ar), 3.08 (m, 1H, CH), 3.73 (br, 1H, CHOH),
6.98 (t, 8.1, 1H, ind.), 7.06 (t, 8.1, 1H, ind.), 7.18 (s, 1H, ind.), 7.34 (d,
8.1, 1H, ind.), 7.54 (d, 8.1, 1H, ind.), 10.88 (s, 1H, NH). Ahipa from 1:
[R]23 + 26.3° (c 0.1, 50% MeOH); HRFABMS m/z 249.1249 [M + H]+
D
(∆ + 1.0 mmu); 1H NMR (DMSO-d6, 600 MHz) δ 2.37 (dd, 15.4, 6.0,
1H, COCH2), 2.42 (dd, 15.4, 5.1, 1H, COCH2), 2.74 (dd, 14.5, 8.1, 1H,
CH2Ar), 3.02 (dd, 14.5, 5.1, 1H, CH2Ar), 3.15 (br, 1H, CH), 3.71 (m,
1H, CHOH), 6.97 (t, 8.1, 1H, ind.), 7.06 (t, 8.1, 1H, ind.), 7.20 (s, 1H,
ind.), 7.34 (d, 8.1, 1H, ind.), 7.54 (d, 8.1, 1H, ind.), 10.88 (s, 1H, NH).
(6) Marfey, P. Carlsberg Res. Commun. 1984, 49, 591-596.