Cryptophycins
FULL PAPER
over Na2SO4 and the solvent was evaporated in vacuo. After flash chro-
matography on silica gel (hexane/EtOAc 3:2) the pure condensation
products of 16a,b were obtained as a viscous oil.
39.3, 37.1, 35.5, 34.8, 28.2, 28.1, 27.1, 27.0, 24.7, 23.1, 21.2, 14.6, 9.5 ppm;
IR (film): n˜ =3345, 1742, 1716, 1505, 1257, 1169 cmꢀ1; MS (ESI): m/z:
calcd for C47H68ClN2O12: 887.4; found: 887.3 [M+H]+.
Condensation product of 16a: Yield: 0.569 g, 95%. Rf =0.41 (PE/EtOAc
1:1); [a]2D0 (1.25 g/100 mL CHCl3): ꢀ35.6; 1H NMR (250 MHz, CDCl3):
d=7.42–7.30 (m, 5H, Ar-H), 7.21 (m, 1H, Ar-H), 7.04 (m, 1H, Ar-H),
6.95–6.85 (m, 2H, Ar-H, NH), 5.22 (d, J=12.2 Hz, 1H, uD-Hb), 5.15 (d,
J=12.2 Hz, 1H, uD-Hb), 5.13 (dd, J=9.5, 3.7 Hz, 1H, uD-Ha), 5.12
(brm, 1H, NH), 4.32 (dd, J=14.0, 6.5 Hz, 1H, uB-Ha), 3.85 (s, 3H,
OCH3), 3.67 (m, 1H, uC-Hb), 3.16 (ddd, J=13.7, 9.2, 4.7 Hz, 1H, uC-Hb),
3.01 (dd, J=13.8, 6.5 Hz, 1H, uB-Hb), 2.93 (m, 1H, uB-Hb), 2.75 (m, 1H,
uC-Ha), 1.89–1.57 (m, 3H, uD-Hb, uD-Hg), 1.39 (s, 9H, OC(CH3)3), 1.16
(d, J=7.2 Hz, 3H, uC-CH3), 0.93 (d, J=6.0 Hz, 3H, uD-Hd), 0.90 ppm;
(d, J=6.2 Hz, uD-Hd); 13C NMR (125.7 MHz, CDCl3): d=173.9, 171.3,
171.2, 155.2, 153.8, 134.9, 131.1, 130.0, 128.7, 128.6, 128.3, 122.1, 112.1,
79.8, 70.8, 67.5, 56.1, 55.9, 55.7, 41.7, 40.3, 39.4, 37.9, 28.3, 24.8, 23.0, 21.5,
14.7 ppm; IR (film): n˜ =3309, 1740, 1659, 1504, 1258, 1173 cmꢀ1; MS
(ESI): m/z: calcd for C32H44ClN2O8: 619.3; found: 619.2 [M+H]+.
Compound 19b: Yield: 0.843 g, 97%. Rf =0.40 (hexane/EtOAc 3:2); [a]D25
(0.152 g/100 mL CHCl3): ꢀ33.6; 1H NMR (500 MHz, CDCl3): d=7.42–
7.29 (m, 5H, Ar-H), 7.29 (m, 1H, Ar-H), 7.17 (m, 1H, Ar-H), 7.14 (m,
1H, NH), 6.84 (m, 1H, Ar-H), 6.76 (ddd, J=15.1, 9.1, 6.0 Hz, 1H,uA-
CH2-CH=), 5.86 (d, J=8.8 Hz, 1H, NH), 5.69 (d, J=15.7 Hz, 1H, uA-
CH-CO), 5.09 (m, 1H, uA-CHCH2), 4.89 (dd, J=9.4, 1.9 Hz, 1H, uD-
Ha), 4.71 (d, J=8.8 Hz, 1H, uA-PhCH), 4.43 (ddd, J=8.0, 8.0, 5.8 Hz,
1H, uB-Ha), 3.85 (s, 3H, OCH3), 3.83 (dd, J=9.7, 2.2 Hz, 1H, uA-CHO),
3.63 (dd, J=13.2, 8.8 Hz, 1H, uC-Hb), 3.29 (dd, J=13.8, 5.0 Hz, 1H, uC-
Hb), 3.25 (dd, J=14.1, 4.7 Hz, 1H, uB-Hb), 2.85 (dd, J=13.5, 9.7 Hz, 1H,
uB-Hb), 2.53 (brd, J=15.1 Hz, 1H, uA-CH2), 2.30 (ddd, J=15.9, 7.7,
7.7 Hz, 1H, uA-CH2), 1.88 (m, 1H, uA-CH3CH), 1.76–1.63 (m, 2H, uD-
Hb, uD-Hg), 1.49 (s, 3H, uA-CH3), 1.48 (s, 9H, OC(CH3)3), 1.47 (m, 1H,
uD-Hb), 1.44 (s, 3H, uA-CH3), 1.35 (s, 9H, OC(CH3)3), 1.18 (s, 3H, uC-
CH3), 1.12 (d, J=6.9 Hz, 3H, uA-CH3CH), 1.09 (s, 3H, uC-CH3), 0.92 (d,
J=6.3 Hz, 3H, uD-Hd), 0.85 ppm (d, J=6.3 Hz, 3H, uD-Hd); 13C NMR
(125.7 MHz, CDCl3): d=175.4, 171.9, 170.7, 165.9, 155.9, 153.6, 142.1,
137.6, 131.3, 131.1, 128.8, 128.6, 128.5, 126.5, 125.8, 121.9, 112.0, 109.0,
81.9, 80.4, 80.0, 79.5, 75.4, 70.3, 56.3, 56.1, 47.5, 43.8, 39.3, 37.6, 35.5, 34.8,
28.2, 28.1, 27.2, 27.0, 24.8, 23.2, 21.8, 21.2, 9.6 ppm; IR (film): n˜ =3352,
1740, 1711, 1699, 1662, 1505, 1256, 1151 cmꢀ1; MS (ESI): m/z: calcd for
C48H69ClNaN2O12: 923.4; found: 923.6 [M+Na]+.
Condensation product of 16b: Yield: 0.530 g, 87%. Rf =0.40 (PE/EtOAc
3:2); [a]2D0 (1.35 g/100 mL CHCl3): ꢀ29.6; 1H NMR (250 MHz, CDCl3):
d=7.43–7.30 (m, 5H, Ar-H), 7.22 (m, 1H, Ar-H), 7.04 (m, 1H, Ar-H),
7.01 (brm, 1H, NH), 6.79 (m, 1H, Ar-H), 5.25 (d, J=12.2 Hz, 1H, uD-
Hb), 5.18 (d, J=12.2 Hz, 1H, uD-Hb), 5.19–5.15 (m, 2H, uD-Ha, NH),
4.34 (m, 1H, uB-Ha), 3.83 (s, 3H, OCH3), 3.55 (dd, J=13.5, 7.9 Hz, uC-
Hb), 3.25 (dd, J=13.4, 4.8 Hz, 1H, uC-Hb), 3.02 (dd, J=13.8, 6.5 Hz, 1H,
uB-CH2Ph), 2.92 (m, 1H, uB-CH2Ph), 1.91–1.57 (m, 3H, uD-Hb, uD-Hg),
1.39 (s, 9H, OC(CH3)3), 1.18 (s, 3H, uC-CH3), 1.17 (s, 3H, uC-CH3), 0.93
(d, J=6.4 Hz, 3H, uD-Hd), 0.90 ppm (d, J=6.4 Hz, 3H, uD-Hd);
13C NMR (62.9 MHz, CDCl3): d=175.9, 171.6, 171.4, 155.1, 153.9, 134.9,
131.3, 131.1, 130.2, 128.7, 128.3, 122.2, 112.1, 79.8, 70.9, 67.7, 56.1, 47.3,
43.8, 39.4, 38.2, 28.3, 24.9, 23.3, 23.0, 22.3, 21.5 ppm; IR (film): n˜ = 3331,
1734, 1669, 1504, 1142 cmꢀ1; MS (ESI): m/z: calcd for C33H46ClN2O8:
633.3; found: 633.3 [M+H]+.
A
solution of the protected acyclic depsipeptide 19a,b in CH2Cl2
(11.0 mLmmolꢀ1) and H2O (1.1 mLmmolꢀ1) was cooled to 08C, then
TFA (10.9 mLmmolꢀ1) was added dropwise and the mixture was stirred
until all starting material and intermediates had disappeared (HPLC
monitoring). Then the solvent was evaporated and the obtained solid was
dried over KOH in vacuo. The obtained deprotected derivative was used
in the next step without further purification.
A solution of the deprotected acyclic depsipeptide (1.0 equiv) in DMF
The condensation product of 16a,b (0.73 mmol) was dissolved in EtOAc
(41.2 mLmmolꢀ1) and Pd/C (10%) (0.103 gmmolꢀ1) was added. Gaseous
nitrogen was conducted for 0.5 h, then the mixture was stirred under a
hydrogen atmosphere (1 atm) for 3 h. The mixture was filtered through a
Celite pad and the solvent was evaporated in vacuo. The crude products
18a,b were used in the next step without further purification.
(52.4 mLmmolꢀ1
) and a solution of HATU (1.5 equiv) in DMF
(52.4 mLmmolꢀ1) were added simultaneously using a dual syringe pump
at a rate of 0.01 mLminꢀ1 to a solution of DIPEA (3.0 equiv) in DMF
(47.1 mLmmolꢀ1) at 08C. The mixture was stirred for 0.5 h at 08C and
for 1 h at RT. The solvent was evaporated in vacuo and the residue was
dissolved in EtOAc (318 mLmmolꢀ1), washed with sat. NaHCO3 solution
and brine and dried over Na2SO4. After evaporation of the solvent in
vacuo, flash chromatography on silica gel (CH2Cl2/EtOH 15:1), and crys-
tallisation from EtOAc/PE pure 20a or b was obtained as a white solid.
20a: Yield: 0.098 g, 77%; m.p. 125–1278C; [a]2D0 (2.020 g/100 mL CHCl3):
Preparation of deprotected 19a,b: A solution of 18a or 18b (1.3 equiv)
in CH2Cl2 (8.9 mLmmolꢀ1) was added to 5 (1.0 equiv) at RT, followed by
NEt3 (1.0 equiv). After cooling the mixture to 08C, DMAP (0.8 equiv)
and EDC (1.63 equiv) were added consecutively. The mixture was stirred
for 1 h at 08C and for 30 h at RT, then the solvent was evaporated in
1
ꢀ5.5; H NMR (500 MHz, CDCl3): d=7.39–7.28 (m, 5H, Ar-H), 7.20 (m,
vacuo and the residue was partitioned between EtOAc (178 mLmmolꢀ1
)
1H, Ar-H), 7.06 (m, 1H, Ar-H), 7.01 (m, 1H, NH), 6.82 (m, 1H, Ar-H),
6.65 (ddd, J=15.5, 10.2, 5.2 Hz, 1H, uA-CH2CH=), 5.94 (s, br, 1H, NH),
5.73 (d, J=15.7 Hz, 1H, uA-CH-CO), 5.04 (ddd, J=10.0, 7.7, 1.3 Hz, 1H,
uA-CHCH2), 4.83 (dd, J=10.0, 3.8 Hz, 1H, uD-Ha), 4.78 (dd, J=13.5,
7.9 Hz, 1H, uB-Ha), 4.58 (d, J=8.2 Hz, 1H, uA-PhCH), 3.86 (s, 3H,
OCH3), 3.77 (dd, J=8.8, 1.3 Hz, 1H, uA-CHO), 3.49 (ddd, J=12.9, 3.5,
3.5 Hz, 1H, uC-Hb), 3.27 (m, 1H, uC-Hb), 3.12 (dd, J=14.4, 5.7 Hz, 1H,
uB-Hb), 2.95 (dd, J=14.4, 7.5 Hz, 1H, uB-Hb), 2.80 (brs, 2H, OH), 2.72
(ddd, J=13.3, 10.5, 6.8 Hz, 1H, uC-Ha), 2.45 (dd, J=13.8, 4.4 Hz, 1H,
uA-CH2), 2.22 (ddd, J=13.7, 11.1, 11.1 Hz, 1H, uA-CH2), 1.79 (m, 1H,
uA-CH3CH), 1.67 (m, 1H, uD-Hb), 1.52–1.40 (m, 2H, uD-Hb, uD-Hg),
1.22 (d, J=7.5 Hz, 3H, uC-CH3CH), 1.01 (d, J=6.9 Hz, 3H, uA-
CH3CH), 0.94 (d, J=6.3 Hz, 3H, uD-Hd), 0.88 ppm (d, J=6.9 Hz, 3H,
uD-Hd); 13C NMR (125.7 MHz, CDCl3): d=175.4, 171.4, 170.7, 165.9,
153.8, 142.1, 140.7, 130.8, 129.9, 128.6, 128.3, 126.8, 124.7, 122.2, 112.1,
76.6, 75.6, 74.8, 71.3, 56.1, 54.0, 40.9, 39.5, 38.0, 37.9, 35.9, 34.8, 24.6, 23.0,
21.5, 14.3, 9.5 ppm; IR (KBr): n˜ =3410, 1747, 1726, 1669, 1504, 1258,
1180 cmꢀ1; MS (ESI): m/z: calcd for C35H46ClN2O9: 673.3; found: 673.3
[M+H]+.
and H2O (90 mLmmolꢀ1). The phases were separated and the organic
phase was washed with cold 5% KHSO4 solution, H2O, sat. NaHCO3 so-
lution and brine and dried over Na2SO4. The solvent was evaporated in
vacuo. After flash chromatography on silica gel (hexane/EtOAc 3:2) pure
19a and 19b were obtained as solid foams. 19a: Yield: 0.180 g, 93%.
Rf =0.40 (hexane/EtOAc 3:2); [a]2D0 (0.775 g/100 mL CHCl3): ꢀ43.5;
1H NMR (500 MHz, CDCl3): d=7.39–7.28 (m, 5H, Ar-H), 7.25 (m, 1H,
Ar-H), 7.11 (m, 2H, Ar-H, NH), 6.83 (m, 1H, Ar-H), 6.73 (ddd, J=14.6,
8.6, 6.1 Hz, 1H, uA-CH2-CH=), 5.89 (d, J=8.2 Hz, 1H, NH), 5.66 (d, J=
15.7, 1H, uA-CH-CO), 5.05 (m, 1H, uA-CHCH2), 4.90 (dd, J=10.0,
1.3 Hz, 1H, uD-Ha), 4.70 (d, J=8.8 Hz, 1H, uA-PhCH), 4.39 (ddd, J=
7.2, 7.2, 4.4 Hz, 1H, uB-Ha), 3.84 (s, 3H, OCH3), 3.81 (brd, J=8.2 Hz,
1H, uA-CHO), 3.72 (m, 1H, uC-Hb), 3.27 (dd, J=13.8, 4.4 Hz, 1H, uB-
Hb), 3.11 (ddd, J=12.1, 10.2, 2.7 Hz, 1H, uC-Hb), 2.87 (dd, J=13.5,
9.7 Hz, 1H, uB-Hb), 2.57 (m, 1H, uC-Ha), 2.50 (m, 1H, uA-CH2), 2.26
(ddd, J=14.8, 9.1, 9.1 Hz, 1H, uA-CH2), 1.86 (m, 1H, uA-CH3CH), 1.74–
1.62 (m, 2H, uD-Hb, uD-Hg), 1.49 (m, 1H, uD-Hb), 1.48 (s, 3H, uA-
CH3), 1.46 (s, 9H, OC(CH3)3), 1.43 (s, 3H, uA-CH3), 1.34 (s, 9H, OC-
(CH3)3), 1.12 (d, 3H, J=8.2 Hz, uC-CH3CH), 1.10 (d, J=7.5 Hz, 3H,
uA-CH3CH), 0.90 (d, J=6.3 Hz, 3H, uD-Hd), 0.83 ppm (d, J=6.3 Hz,
3H, uD-Hd); 13C NMR (125.7 MHz, CDCl3): d=173.4, 171.6, 170.4,
165.9, 155.9, 153.6, 142.0, 137.5, 131.2, 131.0, 128.7, 128.5, 128.5, 126.5,
125.7, 121.9, 112.0, 108.9, 81.8, 80.4, 79.9, 79.5, 75.3, 70.2, 56.1, 42.2, 40.9,
Compound 20b: Yield: 0.106 g, 70%; m.p. 177–1798C; [a]2D0 (1.030 g/
100 mL MeOH): ꢀ32.5; 1H NMR (500 MHz, CD3OD): d=7.41–7.35 (m,
4H, Ar-H), 7.30 (m, 1H, Ar-H), 7.27 (m, 1H, Ar-H), 7.16 (m, 1H, Ar-
H), 6.97 (m, 1H, Ar-H), 6.69 (ddd, J=15.1, 11.3, 3.8 Hz, 1H, uA-
CH2CH=), 5.87 (dd, J=15.1, 1.3 Hz, 1H, uA-CH-CO), 5.10 (dd, J=9.7,
Chem. Eur. J. 2005, 11, 4667 – 4677
ꢀ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4675