Full Paper
for H and 63 MHz for 13C (Bruker Avance 250), 400 MHz for H and
100 MHz for 13C (Bruker Avance 400), and 600 MHz for 1H and
150 MHz for 13C (Bruker Avance III) in deuteriated chloroform,
methanol, or dimethyl sulfoxide. Chemical shifts are reported in
ppm relative to the residual solvent peak. Data are reported as fol-
lows: Chemical shift (d), multiplicity (s for singlet, d for doublet, t
for triplet, q for quartet, quint for quintuplet, and m for multiplet),
coupling constant (J in Hertz), and integration. DOSY NMR spec-
troscopy was carried out at the Laboratoire de Mesures Physiques,
IBMM-Universitꢀ Montpellier 2. TLC analyses were performed on
Merck silica gel 60F254 with detection under UV light (254 nm) or
by staining with either a ninhydrin solution in ethanol or a 2,4-dini-
trophenylhydrazine (DNPH) solution, followed by heating. Flash
chromatography was performed on silica gel (40–63 mm) pur-
chased from Merck. LC/ESI-MS analyses were performed on
a Waters HPLC 2695 instrument (EC Nucleosil 300-5 C18, 125ꢃ
3 mm column, Macherey-Nagel) equipped with a Waters 996 DAD
detector and a Waters Micromass ZQ mass spectrometer (positive
mode detection) with the following linear gradients of solvent B
(90% acetonitrile, 9.9% water, and 0.1% TFA) and solvent A (99.9%
water and 0.1% TFA): Method A: 5 to 100% of solvent B in 5 min;
flow: 1 mL/min; Method B: 5 to 100% of solvent B in 20 min; flow:
1 mL/min. Retention times (tR) are given in minutes. MALDI-TOF
and high-resolution mass spectrometry (HRMS, positive mode)
were carried out at the Laboratoire de Mesures Physiques, IBMM-
Universitꢀ Montpellier 2 by using Ultraflex III and Micromass Q-Tof
instruments, respectively. Fluorescence analyses were carried out
on an A F-2500 HITACHI fluorescence spectrophotometer.
to 7:0.25:0.25, v/v/v) to provide 2 (yield 26%) as an oil. Rf =0.39
(iPrOH/H2O/NH4OH 7:0.5:0.5, v/v/v); tR 3.02 min (Method A); 1H
NMR (400 MHz, CD3OD): d=7.82 (d, J=8.0 Hz, 4H; CH=CH), 7.46
(d, J=8.0 Hz, 4H; CH=CH), 3.82 (s, 4H; PhCH2N), 2.72 (s, 8H;
NHCH2CH2), 1.50 ppm (s, 18H; tBu); MS (ESI): m/z calcd for
1
1
C30H46N7O6 [M+H]+ 600.35; found: 600.65.
+
4-[({2-[(2-{[4-(hydrazinylcarbonyl)benzyl]amino}ethyl)amino]e-
thyl}amino)methyl]benzhydrazide (EI-Hyd): Compound 2 (25 mg,
0.42 mmol) was dissolved in a solution of TFA/H2O/TIS (95:2.5:2.5,
v/v/v; 10 mL) and stirred for 48 h at room temperature. After re-
moval of 90% of the solvent, diethyl ether was added to the resid-
ual solution. The precipitate residue was triturated with Et2O and
filtered. The material was then lyophilized twice to afford the tri-
fluoroacetate salt EI-Hyd as a sticky solid in 80% yield. The yield
1
was calculated by a H NMR titration method using tert-butyl alco-
1
hol as an internal reference. H NMR (600 MHz, d6-DMSO): d=7.92
(d, J=8.3 Hz, 4H; CH=CH), 7.64 (d, J=8.3 Hz, 4H; CH=CH), 4.29 (s,
4H; PhCH2N), 3.29-3.27 ppm (m, 8H; NHCH2CH2); 13C NMR
(150 MHz, [D6]DMSO): d=165.3, 158.8 (TFA), 135.9, 132.1, 130.0,
127.7, 116.0 (TFA), 49.8, 43.2 (2C); HRMS (ESI): m/z calcd for
+
C20H30N7O2 400.2461; found: 400.2456.
tert-Butyl 2-{4-[({13-[({4-[2-(tert-butoxycarbonyl)hydrazinylcarbo-
nyl]phenyl}methyl)amino]-4,7,10-trioxatridecyl}amino)methyl]-
benzoyl}hydrazine-1-carboxylate (3): Compound 1 (480.10 mg,
1.82 mmol) was added to a solution of 4,7,10-trioxa-1,13-tridecane-
diamine (200 mg, 0.91 mmol) in dry methanol (5 mL) under argon
at 08C. The reaction solution was stirred at room temperature for
48 h. Then sodium borohydride (103.30 mg, 2.73 mmol) was added
to the solution cooled to 08C. The reaction was warmed to room
temperature and stirred for 24 h. After removal of the solvent, the
residue was purified by flash chromatography (iPrOH/H2O/NH4OH
gradient 7:0.1:0.1 to 7:0.2:0.2, v/v/v) to provide 3 as an oil in 22%
yield. Rf =0.27 (iPrOH/H2O/NH4OH 7:0.2:0.2, v/v/v); tR 2.64 min
(Method A); 1H NMR (400 MHz, CDCl3): d=7.65 (d, J=8.0 Hz, 4H;
CH=CH), 7.24 (d, J=8.0 Hz, 4H; CH=CH), 3.74 (s, 4H; PhCH2N),
3.58–3.56 (m, 4H; NHCH2CH2CH2), 3.54–3.51 (m, 8H; OCH2CH2O),
2.71 (t, J=6.0 Hz, 4H; NHCH2), 1.79 (quint, J=6.0 Hz, 4H;
NHCH2CH2CH2), 1.46 ppm (s, 18H; tBu); MS (ESI): m/z calcd for
Synthetic procedures and characterizations
tert-butyl 2-(4-formylbenzoyl)hydrazine-1-carboxylate (1): Thio-
nyl chloride (145 mL, 2.01 mmol) was added to a solution of 4-for-
mylbenzoic acid (100 mg, 0.67 mmol) in dry toluene (3 mL) under
argon . The reaction solution was stirred at reflux overnight under
argon. The solvent was removed under reduced pressure under
dry conditions to afford the crude 4-formylbenzoyl chloride as
a yellow solid. Then tert-butyl carbazate (88 mg, 0.67 mmol) and
triethylamine (139 mL, 1.00 mmol) were added to a stirred solution
of the crude acyl chloride in dry CH2Cl2 (3 mL) at 08C. The reaction
solution was then warmed to room temperature and stirred for
48 h. After removal of the solvent, the residue was diluted with
EtOAc (15 mL), washed with saturated NaHCO3 solution (15 mL)
and brine (15 mL), dried over anhydrous Na2SO4, and concentrated
in vacuo. The resulting crude material was purified by flash chro-
matography (petroleum ether/EtOAc gradient 7:3 to 5:5, v/v) to
provide 1 (yield 55%) as a white solid. Rf =0.31 (petroleum ether/
EtOAc 6:4, v/v); tR =3.16 min (Method A); 1H NMR (400 MHz,
CDCl3): d=10.04 (s, 1H; Haldehyde), 8.93 (brs, 1H; NH), 7.94 (d, J=
8.0 Hz, 2H; CH=CH), 7.87 (d, J=8.0 Hz, 2H; CH=CH), 6.96 (brs, 1H;
NH), 1.48 ppm (s, 9H; tBu); 13C NMR (100 MHz, CDCl3): d=191.5,
165.8, 156.2, 138.6, 136.8, 129.9, 128.2, 82.6, 28.3 ppm; MS (ESI): m/
C36H57N6O9 [M+H]+ 717.42; found: 717.40.
+
4-{[(13-{4-[(Hydrazinylcarbonyl)phenyl]amino}-4,7,10-trioxatride-
cyl)amino]methyl}benzhydrazide
(EG-Hyd):
Compound
3
(145.6 mg, 0.20 mmol) was dissolved in a solution of TFA/H2O/TIS
(95:2.5:2.5, v/v/v; 8 mL) and stirred for 24 h at room temperature.
After removal of 90% of the solvent, diethyl ether was added to
the residue. The precipitate was triturated with Et2O and filtered.
The crude material was then lyophilized twice to afford the trifluor-
oacetate salt EG-Hyd as a sticky solid in 55% yield. The yield was
1
calculated by a H NMR titration method using tert-butyl alcohol as
an internal reference. tR 2.93 min (Method B); 1H NMR (600 MHz,
[D6]DMSO): d=7.92 (d, J=8.1 Hz, 4H; CH=CH), 7.62 (d, J=8.1 Hz,
4H; CH=CH), 4.24 (s, 4H; PhCH2N), 3.48–3.45 (m, 12H;
NHCH2CH2CH2OCH2CH2O), 3.00 (t, J=6.0 Hz, 4H; NHCH2), 1.88 ppm
(quint, J=6.0 Hz, 4H; NHCH2CH2CH2); 13C NMR (150 MHz,
[D6]DMSO): d=165.3, 158.7 (TFA), 136.2, 131.9, 130.0, 127.7, 116.0
(TFA), 69.7, 69.5, 67.3, 49.6, 44.6, 25.8 ppm; HRMS (ESI): m/z calcd
z calcd for C13H17N2O4 [M+H]+ 265.12; found: 265.24; HRMS (ESI):
+
m/z calcd for C8H9N2O2 [MÀBoc+H]+ 165.0664; found: 165.0665.
+
tert-Butyl 2-[4-({[2-({2-[({4-[2-(tert-butoxycarbonyl)hydrazinylcar-
bonyl]phenyl}methyl)amino]ethyl}amino)ethyl]amino}methyl)-
benzoyl]hydrazine-1-carboxylate (2): Compound
+
for C26H41N6O5 517.3138; found: 517.3135.
1 (200 mg,
0.76 mmol) was added to a solution of diethylenetriamine (41 mL,
0.38 mmol) in dry methanol (2 mL) under argon at 08C. The reac-
tion mixture was stirred at room temperature for 48 h. Then
sodium borohydride (43 mg, 1.14 mmol) was added to the solution
cooled to 08C. The reaction was warmed to room temperature and
stirred for 24 h. After removal of the solvent, the residue was puri-
fied by flash chromatography (iPrOH/H2O/NH4OH gradient 7:0.1:0.1
4-(Dimethoxymethyl)benzylamine (4): The procedure was adapt-
ed from a previous report.[39] Trimethyl orthoformate (19 mL,
173.4 mmol) and concentrated aqueous HCl (260 mL, 8.67 mmol)
were added to
a solution of 4-cyanobenzaldehyde (3.79 g,
28.9 mmol) in dry MeOH (50 mL) under argon. The reaction solu-
tion was heated at 458C for 3 h 30 min. The solvent was then re-
moved under reduced pressure and the residue was diluted with
Chem. Eur. J. 2014, 20, 14705 – 14714
14711
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim