â-Sheet Ligands in Action
A R T I C L E S
(100 MHz, DMSO-d6): δ 17.8, 19.9, 23.0, 23.2, 28.2, 29.2, 30.9, 31.0,
36.4, 51.6, 52.7, 52.8, 53.3, 53.4, 55.0, 57.0, 77.2, 99.8, 100.0, 113.6,
113.8, 126.4, 129.1, 128.6, 128.9, 129.1, 129.7, 129.8, 134.0, 134.6,
136.9, 145.2, 146.1, 155.5, 157.2, 158.6, 158.7, 159.2, 167.5, 170.9,
171.3, 171.7. MS (ESI): m/z 1029 (M + Na)+, 1007 (M + H)+.
HRMS: calcd for C52H66N10O11Na, 1029.4810; found, 1029.4944.
Mp: >240 °C. Rf: 0.22 in chloroform/methanol (30:1).
Pz(PMB)-OMe] was stirred together with 5 mol % Pd/C (Degussa Typ
E101 NE/W) in methanol under a H2 atmosphere until the starting
material disappeared on TLC. The catalyst was removed by filtration
over kieselguhr, and the solvent was evaporated. The residue was
purified by column chromatography on silica gel using dichloromethane/
methanol (10:1). Yield: 350 mg (714 µmol, 74%), colorless solid. 1H
NMR (300 MHz, CDCl3): δ 1.42 (s, 9H, CH3-tBu), 1.41-1.45 (m,
4H, CH2-Lys), 1.62-1.70 (m, 1H, CH2-Lys), 1.86-1.95 (m, 1H, CH2-
Lys), 3.08-3.11 (m, 3H, CH2-Lys, NH), 3.56-3.63 (s, 2H, NH2), 3.77
(s, 3H, CH3-PMB), 3.84 (s, 3H, OOCH3), 4.62 (brs, 1H, R-CH), 5.59
(s, 2H, CH2-PMB), 6.82 (d, J ) 8.6 Hz, 2H, CH-arom.), 7.19 (d, J
) 8.6 Hz, 2H, CH-arom.), 7.26 (s, 1H, CH-pyrazole), 9.99 (brs, 1H,
NH). MS (ESI): 490 (M + K)+, 512 (M + Na)+. HRMS: calcd for
C24H35N5O56Na, 512.2485 found, 512.2507. Rf: 0.41 in dichlo-
romethane/methanol (10:1). [R]Na: +8.3, T ) 21 °C, c ) 1.00 in
methanol. Mp: 52 °C.
5-Acetylamino-2H-pyrazole-3-carbonylamino-2H-pyrazole-3-car-
bonyl-(S)-lysinyl-(S)-valinyl-(S)-phenylalanine Methyl Ester Tri-
fluoroacetate [Ac-PzPzKVF-OMe], 1. A 100 mg (99.3 µmol, 1.00
equiv) amount of 5-acetylamino-2-[4-methoxybenzyl]-2H-pyrazole-3-
carbonylamino-2-[4-methoxybenzyl]-2H-pyrazole-3-carbonyl-Nꢀ-tert-
butyloxyarbonyl-(S)-lysinyl-(S)-valinyl -(S)-phenylalanine methyl ester
[Ac-Pz(PMB)Pz(PMB)K(Boc)VF-OMe] was stirred under an inert
atmosphere in dry trifluoroacidic acid for 2-3 h at 70 °C. After cooling
to room temperature, ice-cold diethyl ether was added. The product
precipitated as a colorless solid. This was centrifuged off, washed
several times with ice-cold diethyl ether, and dried in vacuo to yield
3
3
N-Benzyloxycarbonyl-NE-tert-butyloxycarbonyl-(S)-lysinyl-NE-tert-
butyloxycarbonyl-(S)-lysinyl-5-amino-2-(4-methoxybenzyl)-2H-pyra-
zole-3-carboxylic Acid Methyl Ester [Z-Lys(Boc)-Lys(Boc)-Pz-
(PMB)-OMe]. A 300 mg (675 µmol, 1.00 equiv) amount of Nꢀ-tert-
butyloxycarbonyl-(S)-lysinyl-5-amino-2-(4-methoxybenzyl)-2H-pyrazol-
3-carboxylic acid methyl ester [H-Lys(Boc)-Pz(PMB)-OMe] and 308
mg (810 µmol, 1.20 equiv) of N-benzyloxycarbonyl-Nꢀtert-butyloxy-
carbonyl-(S)-lysine were reacted with 335 mg (810 µmol, 1.20 equiv)
of HCTU, 344 mg (2.02 mmol, 3.00 equiv) of Cl-HOBT, and 284 µL
(2.43 mmol, 3.60 equiv) of 2,6-lutidine according to general procedure
A. Yield: 431 mg (506 µmol, 72%), pale yellow solid. 1H NMR (300
MHz, CDCl3): δ 1.33-1.99 (m, 12H, CH2-Lys), 1.40, 1.41 (2s, 18H,
CH3-tBu), 3.01-3.08 (m, 4H, CH2-Lys), 3.73 (s, 3H, CH3-PMB), 3.86
(s, 3H, OOCH3), 4.14-4.12 (m, 1H, R-CH), 4.62-4.75 (m, 3H, R-CH,
NH-Boc), 5.11 (s, 2H, CH2-PMB), 5.49 (d, 2J ) 14.7 Hz, 1H, CH2-Z),
1
compound 1. Yield: 90 mg (89 mmol, 90%). H NMR (500 MHz,
3
3
MeOH-d3): δ 0.80 (d, J ) 6.9 Hz, 3H, CH3-Val), 0.83 (d, J ) 6.9
Hz, 3H, CH3-Val), 1.35-1.47 (m, 2H, CH2-Lys), 1.63-1.69 (m, 2H,
CH2-Lys), 1.74-1.70 (m, 2H, CH2-Lys), 1.99-2.05 (m, 1H, CH-iprop),
2
2.14 (s, 3H, CH3-Acetyl), 2.84-2.91 (2H, CH2-Lys), 2.98 (dd, J )
13.9 Hz, 3J ) 8.4 Hz, 1H, CH2-Phe), 3.12 (dd, 2J ) 13.9 Hz, 3J ) 5.8
Hz, 1H, CH2-Phe), 3.64 (s, 1H, OOCH3), 4.22 (dd, 3J ) 8.3 Hz, 3J )
7.6 Hz, 1H, R-CH), 4.57-4.66 (m, 2H, R-CH), 6.81, 6.88 (2s, 2H,
CH-pyrazole), 7.17-7.27 (m, 5H, CH-arom.), 7.75 (brs, 3H, NH3+),
8.04 (d, 3J ) 8.4 Hz, 1H, NH), 8.34 (d, 3J ) 7.8 Hz, 1H, NH), 8.53 (d,
3J ) 7.6 Hz, 1H, NH), 10.68, 10.84 (s, 2H, NH). The pyrazole NHs
are broadened. 13C NMR (125 MHz, MeOH-d3): δ 18.5, 19.4, 22.8,
23.6, 28.1, 32.0, 32.5, 38.3, 40.7, 52.5, 54.1, 55.3, 60.0, 95.9, 96.4,
127.7, 129.4, 130.1, 134.3, 134.5, 137.9, 144.2, 144.9, 160.6, 162.9,
171.2, 173.1, 173.5, 173.7. MS (ESI): m/z 667 (M + H)+. HRMS
(ESI): calcd for C31H43N10O7, 667.3316; found, 667.3332. Mp: 165
°C.
2
3
5.61 (d, J ) 14.7 Hz, 1H, CH2-Z), 6.07 (brs, 1H, NH), 6.70 (d, J )
3
3
8.3 Hz, 1H, NH), 6.76 (d, J ) 8.6 Hz, 2H, CH-arom.), 7.14 (d, J )
8.6 Hz, 2H, CH-arom.), 7.25 (s, 1H, CH-pyrazole), 7.31 (brs, 5H, CH-
arom.), 9.18 (s, 1H, NH). 13C NMR (75 MHz, CDCl3): δ 22.7, 22.8,
28.5, 29.5. 29.7, 32.5, 39.9, 40.3, 52.1, 53.4, 53.9, 55.2, 55.3, 67.2,
79.2, 102.8, 114.1, 128.3, 128.6, 128.8, 129.1, 129.3, 132.1, 136.4,
145.6, 156.3, 156.4, 159.2, 160.0, 169.5, 172.5. MS (ESI): m/z 875
(M + Na)+. HRMS (ESI): calcd for C43H61N7O11Na, 874.4327; found,
874.4322. Mp: 101 °C. Rf: 0.57 in dichloromethane/methanol (10:1).
[R]Na: -10.1, T ) 20 °C, c ) 1.00 in chloroform.
N-Benzyloxycarbonyl-NE-tert-butyloxycarbonyl-(S)-lysinyl-5-amino-
2-(4-methoxybenzyl)-2H-pyrazole-3-carboxylic Acid Methyl Ester
[Z-Lys(Boc)-Pz(PMB)-OMe]. A 1.04 g (4.00 mmol, 1.00 equiv)
amount of 5-amino-2-(4-methoxybenzyl)-2H-pyrazole-3-carboxylic acid
methyl ester 552 and 1.67 g (4.40 mmol, 1.10 equiv) of N-benzyloxy-
carbonyl-Nꢀ-tert-butyloxycarbonyl-(S)-lysine were reacted with 1.82 g
(4.40 mmol, 1.10 equiv) of HCTU, 1.86 g (11.0 mmol, 2.75 equiv) of
Cl-HOBt, and 1.50 mL (13.2 mmol, 3.30 equiv) of 2,6-lutidine in a
mixture of dry dichloromethane and dry DMF (3:1) according to general
procedure A. The crude product was purified by column chromato-
graphy on silica gel using chloroform/methanol (25:1) to yield the
NE-tert-Butyloxycarbonyl-(S)-lysinyl-NE-tert-butyloxycarbonyl-(S)-
lysinyl-5-amino-2-(4-methoxybenzyl)-2H-pyrazole-3-carboxylic Acid
Methyl Ester [H-Lys(Boc)-Lys(Boc)-Pz(PMB)-OMe], 8. To a solution
of 400 mg (469 µmol, 1.00 equiv) of N-benzyloxycarbonyl-Nꢀ-tert-
butyloxycarbonyl-(S)-lysinyl-Nꢀ-tert-butyloxycarbonyl-(S)-lysinyl-5-
amino-2-(4-methoxybenzyl)-2H-pyrazole-3-carboxylic acid methyl ester
[Z-Lys(Boc)-Lys(Boc)-Pz(PMB)-OMe] in methanol was added 5 mol
% Pd/C (Degussa Typ E101 NE/W). The reaction mixture was stirred
under a H2 atmosphere until the starting material disappeared on TLC.
Then the mixture was filtrated over kieselguhr, and the solvent was
evaporated. The residue was purified by column chromatography on
silica gel using dichloromethane/methanol (10:1) to yield compound 8
1
compound as a yellow solid. Yield: 1.50 mg (2.41 mmol, 60%). H
NMR (500 MHz, CDCl3): δ 1.39 (s, 9H, CH3-tBu), 1.39-1.45 (m,
4H, CH2-Lys), 1.67-1.71 (m, 1H, CH2-Lys) 1.86-1.92 (m, 1H, CH2-
Lys), 3.05 (brs, 2H, CH2-Lys), 3.96 (s, 3H, CH3-PMB) 4.05 (s, 3H,
OOCH3), 4.35-4.39 (m, 1H, R-CH), 4.69 (brs, 1H, NH), 5.05 (d, 2J )
20.8 Hz, 2H, CH2-PMB), 5.13 (d, 2J ) 20.8 Hz, 2H, CH2-PMB), 5.77
3
(s, 2H, CH2-Z), 5.81 (brs, 1H, NH), 6.03 (d, J ) 8.0 Hz, 2H, CH-
arom.), 7.15 (d, 3J ) 8.0 Hz, 2H, CH-arom.), 7.25-7.31 (m, 6H, CH-
pyrazole, CH-arom.), 9.20 (brs, 1H, NH). 13C NMR (500 MHz,
CDCl3): δ 22.3, 28.3, 29.4, 31.8, 31.9, 38.6, 39.6, 51.9, 53.8, 55.2,
67.2, 102.6, 109.5, 113.8, 120.1, 126.0, 128.0, 128.1, 128.4, 128.8,
128.9, 131.9, 136.0, 145.4, 156.4, 159.1, 159.9, 169.8. MS (ESI): m/z
646 (M + Na, 70)+. HRMS: calcd for C32H41N5O8Na, 646.2853; found,
646.2862. Rf: 0.18 in chloroform/methanol (25:1). [R]Na: -6.2, T )
20 °C, c ) 1.00 in chloroform. Mp: 115 °C.
1
as a colorless solid. Yield: 305 mg (425 µmol, 91%). H NMR (500
MHz, DMSO-d6): δ 1.34, 1.54 (2s, 18H, CH3-tBu), 1.15-1.87 (m,
14H, CH2-Lys, NH2), 2.84-2.88 (m, 4H, CH2-Lys), 3.11-3.14 (m,
1H, R-CH), 3.71 (s, 3H, CH3-PMB), 3.82 (s, 3H, OOCH3), 4.39 (brs,
1H, R-CH), 5.51 (d, 2J ) 14.9 Hz, 1H, CH2-PMB), 5.55 (d, 2J ) 14.9
3
Hz, 1H, CH2-PMB), 6.71 (brs, 2H, 2NH), 6.87 (d, J ) 8.7 Hz, CH-
3
arom.), 7.06 (s, 1H, CH-prazole), 7.15 (d, J ) 8.7 Hz, CH-arom.),
8.03, (brs, 1H, NH), 10.78 (s, 1H, NH). 13C NMR (75 MHz, DMSO-
d6): δ 22.4, 22.5, 28.2, 28.5, 29.1, 29.4, 31.9, 34.6, 52.1, 52.3, 53.1,
54.5, 55.0, 77.2, 99.3, 101.9, 113.8, 128.7, 129.1, 131.1, 145.9, 155.5,
158.7, 159.3, 170.3, 175.1. MS (ESI): m/z 741 (M + Na)+. HRMS:
calcd for C35H55N7O9Na, 740.3959; found, 740.3941. Mp: 56 °C.
NE-tert-Butyloxycarbonyl-(S)-lysinyl-5-amino-2-(4-methoxyben-
zyl)-2H-pyrazole-3-carboxylic Acid Methyl Ester [H-Lys(Boc)-Pz-
(PMB)-OMe]. A 600 mg (963 µmol, 1.00 equiv) amount of N-ben-
zyloxycarbonyl-Nꢀ-tert-butyloxycarbonyl-(S)-lysinyl-5-amino-2-(4-
methoxybenzyl)-2H-pyrazole-3-carboxylic acid methyl ester [Z-Lys(Boc)-
9
J. AM. CHEM. SOC. VOL. 127, NO. 9, 2005 3023