(5.11 mmol) of hydrazine hydrate was◦added. The solution was
refluxed overnight before cooling to 4 C and filtered. 40 mL of
1 M HCl was added and the solution boiled down to ~40 mL. The
remaining solvent was removed to dryness by rotary evaporation,
leaving the crude product. The final product was purified on a
DOWEX cation exchange column (10 mm ¥ 20 cm). The column
was prepared for use by washing with 6 M HCl (250 mL), then
0.5 M HCl (250 mL) and finally distilled water until the pH was
about 6. The crude compound was dissolved in a minimum of
0.2 M HCl and was loaded onto the column. The column was
washed with 500 mL 0.2 M HCl, 500 mL 0.5 M HCl, with the
final product in 0.5 M HCl. The solvent was removed by rotary
evaporation leaving a yellow oily residue. (Yield: 0.900 g, 67%). 1H
NMR (CD3OD): d (ppm) 2.25 (m, 4H, CH2), 3.13 (t, 4H, CH2),
3.19 (s, 6H, CH3), 3,51 (t, 4H, CH2).
to a stirred solution of 0.3783 g (1.25 mmol) of trans-
diamminedichloroplatinum(II) in 10 mL DMF, and stirred for
18 h in the absence of light under a dry nitrogen atmosphere.
The mixture was filtered through a 0.5 mm PETE syringe filter,
and cooled to -20 ◦C in a 1 : 3 NaCl : ice (w/w) bath. 2.4 mL
of a 0.245 M solution (185 mg) of 3-amino-N-(3-aminopropyl)-
N,N-dimethylpropan-1-aminium triflate was added drop-wise
over 10 min. The solution was stirred at -20 ◦C for 3 h, then
at RT for 1 h. The solution was dried in vacuo then washed
with ether : acetone 1 : 1 then dissolved in water and freeze-dried.
The resulting yellow solid was fractionally crystallized from
0.2 M HCl and MeOH, then dried to give the product as a
mixed triflate–chloride salt. (Yield: 67 mg). For analysis, the
-
product was precipitated as the PF6 salt by addition of excess
NH4PF6 in a concentrated aqueous solution. Anal. Calc. for
C8H34N7Cl2F18P3Pt2: C: 8.55%; H: 3.05%; N: 8.72%, Found: C:
9.16%; H: 3.13%; N: 8.40%. The product was then dissolved in
a minimum volume of H2O. 10 g of anion exchange resin was
treated with saturated NaCl solution, and then washed with
excess H2O. The solution containing the platinum compound was
added to the resin and stirred for 10 min. The resin was removed
by filtration and washed with 3 ¥ 10 mL of H2O. The combined
washings were freeze-dried to give CT233 in near quantitative
3-Amino-N-(3-aminopropyl)-N,N-dimethylpropan-1-aminium
triflate. 0.350 g (1.24 mmol) of 3-amino-N-(3-aminopropyl)-
N,N-dimethylpropan-1-aminium chloride, dihydrochloride was
dissolved in a minimum volume of water. Dowex anion exchange
resin was prepared for use by washing it with 150 mL of 3 M
NaOH. The resin was washed with approx. 500 mL water or until
the eluant was ~pH 7.0. The compound was then loaded onto the
resin, and left for 10 min, before washing with 3 ¥ 30 mL volumes
of water. The combined washings were then titrated with 1.0 g of
triflic acid dissolved in 5 mL of water, until pH reached ~9.5. The
compound was freeze-dried. (Yield: 0.345 g, 86%).
1
yield. H NMR (D2O): d (ppm) 2.24 (m, 4H, CH2), 2.80 (t, 4H,
CH2), 3.14 (s, 6H, CH3), 3.44 (t, 4H, CH2).
Q[n] encapsulation of platinum complexes
For Q[7] titrations, a stock solution of Q[7] in D2O (~5 mM) was
added in 20 mL aliquots to a solution containing 0.5 mmol of
the relevant platinum complex in 0.7 mL of D2O. Q[8] titrations
where conducted by dissolving solid portions of Q[8] (~0.3 mg,
0.2 mmol) in 0.7 mL of D2O containing ~0.5 mmol of the relevant
Pt complex. 1D 1H NMR spectra where recorded for each
addition and NOESY and/or COSY spectra where taken at 1 : 1
platinum complex to cucurbituril ratio when assignments were not
straightforward.
Synthesis of platinum complexes
{Bis[trans-diamminechloroplatinum(II)](l-[N-(3-aminopropyl)-
propane-1,3-diamine])} dichloride, hydrochloride (CT033).
CT033 was prepared by a method based on that of Qu and
Farrell.24 0.2015 g (1.186 mmol) of AgNO3 was dissolved in
3 mL of DMF and added drop-wise to a stirred solution of
0.3675 g (1.22 mmol) of trans-diamminedichoroplatinum(II) in
10 mL DMF, and stirred for 18 h in the absence of light under
a dry nitrogen atmosphere. The mixture was filtered through
a 0.5 mm PETE syringe filter, and cooled to -20 ◦C in a 3 : 1
ice : NaCl (w/w) bath. 0.1316 g (0.569 mmol) of tert-butyl bis(3-
aminopropyl)carbamate in 3 mL of DMF was added drop-wise
over 10 min. The solution was stirred at -20 ◦C for 3 h, then at RT
for 1 h, under anhydrous conditions. The solvent was removed in
vacuo, and the product stirred in 30 mL of ether : acetone (1 : 1
v/v) overnight. The supernatant liquid was pippetted off and the
solid dissolved in a minimal quantity of MeOH. 5 mL of conc.
HCl was added and the solution stirred over 72 h. The mixture
was cooled to 4 ◦C overnight and then filtered. The resulting
yellowish solid was washed with 2 ¥ 10 mL volumes of acetone,
then ether, then dried in vacuo to give CT033 as a yellowish solid.
(Yield: 0.342 g 78%). Anal. Calc. for C6H30N7Cl5Pt2: C: 9.39%;
H: 3.94%; N: 12.77%. Found: C: 9.59%; H: 3.83%; N: 12.31%. 1H
NMR (D2O): d(ppm) 2.12 (m, 4H, CH2), 2.80 (m, 4H, CH2), 3.16
(t, 4H, CH2).
Cysteine reaction assays
A stock solution of buffered cysteine in simulated physiological
conditions was prepared from 120 mM NaCl, 2.7 mM KCl,
26.3 mM KH2PO4, 123.6 mM Na2HPO4 and 4 mM L-cysteine in
D2O solution, as previously described.8 The isotope pH effect was
not accounted for. All solutions were gassed with argon. Free or
cucurbituril encapsulated platinum drug sufficient to form 1 mM
solutions was dissolved in 0.7 mL of the stock solution at 37 ◦C and
a 1D 1H NMR spectrum was taken immediately. Further spectra
were taken at regular intervals.
Cytotoxicity assays
The murine leukaemia line L1210 and the cisplatin resistant
subline L1210/DDP were grown in RPMI 1640 medium supple-
mented with 10% fetal bovine serum (CSL Ltd, Australia). The
cells were maintained in a humidified incubator with 5% CO2 in air
at 37 ◦C and were tested routinely for mycoplasma. Cytotoxicity
was determined using growth inhibition assays. The metal complex
was dissolved in warm ultrapure water and then diluted to the
required concentrations in complete medium. Growth inhibition
{Bis[trans-diamminechloroplatinum(II)](l-[3-amino-N-(3-amino-
propyl)-N,N-dimethylpropan-1-ol-aminium])} trichloride (CT233).
CT233 was prepared by a method based on that of the
groups of Rendina25 and Farrell.24 0.3220 g (1.25 mmol) of
AgOTf was dissolved in 3 mL of DMF and added drop-wise
5192 | Dalton Trans., 2009, 5190–5198
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The Royal Society of Chemistry 2009
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