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PNAs embedding NLS peptide
Yields 30-35%. Methyl ester deprotections were performed by dissolving the backbones in
CH 3 OH:H 2 O = 1:1 (10 ml) and by adding NaOH up to a final concentration of 0.25 M. The
mixtures were refluxed for 2.5 hour, then CH 3 OH was evaporated and the products were
precipitated as white solids at pH 5.5, filtered and dried under vacuum. Yields: 87-90%. Fmoc
protections of the secondary amines were achieved by mixing the zwitterionic backbones in
CH 2 Cl 2 , in flasks equipped with CaCl 2 drying valves. Bis(trimethylsilyl)acetamide (BTSA, 2
eq) and DIPEA (1.5 eq) were then added and when the solutions were nearly clear (10-15 min
were usually required), Fmoc chloride (2 eq) was added and the mixtures were stirred for 2
hours at room temperature. CH 3 OH (1 ml ) was then carefully added and the mixtures were
stirred for additional 15 min, diluted with CH 2 Cl 2 , washed with 1M KHSO 4 (3 times) and
saturated NaCl (1 time), dried over MgSO 4 and evaporated to dryness. The residues were
purified by flash chromatography (dichloromethane : methanol = 9:1) and the products were
obtained as white foams (Yields 30-35%).
Compounds 2 (a- L-Val methyl ester hydrochloride, b- L-Arg-N ω -Tosyl methyl ester
hydrochloride)..Compound 2 a: Yield: Quantitative. 1 H NMR (300MHz ,CDCl 3 , 25°C):
δ(ppm): 8.82 (sb, 1H, NH + 3 ), 3.90-4.03 (m, 1H, CHα), 3.8 (s, 3H, methyl ester), 2.41-2.53 (m,
1H, CH side chain), 1.20 (dd, 6, J=3 Hz, 7Hz, CH 3 side chain). 13 C NMR (75 MHz, CDCl 3 ):
δ(ppm) 169.1, 57.1, 54.4, 29.1, 18.3, 17.4. ESI-MS (CH 3 OH, positive ions): calculated m/z:
131.1 (MH + ), 154.1 (MNa + ); found: 132.0, 154.0. Compound 2 b: 1 H NMR (300MHz ,[D 6 ]-
DMSO, 25°C): δ(ppm) : 10.37 (sb, 3H, N-H amine), 8.64 (sb, 1H, N-Hη arginine side chain),
7.64 ( d, 2H, J= 6 Hz aromatic tosyl group), 7.38 (sb, 1H, N-Hε arginine side chain), 7.29 ( d,
2H, J= 6 Hz aromatic tosyl group ), 6.79 (sb, 1H, N-Hη arginine side chain), 3.99-3.97
(m,1H, C-H α), 3.71 (s, 3H, methyl ester), 3.1-3.05(m, 2H, CH 2 arginine side chain), 2.34 (s,
3H, tosyl methyl group), 1.77-1.72 (m, 2H, CH 2 arginine side chain), 1.49-1.44 (m, 2H, CH 2
arginine side chain). 13 C NMR (75 MHz, CDCl 3 ):δ(ppm) 169.6,156.6, 141.3, 141.0,129.0,
125.6, 52.6, 51.4, 48.4, 27.0, 24.4, 20.8. ESI-MS (CH 3 OH, positive ions): calculated m/z:
343.1 (MH + ) found: 343.3. HRMS (ESI + ): calcd m/z for C 14 H 23 N 4 O 4 S (MH + ): 343.1440,
found: 343.1443
Compound 3 (N α -Boc-L-Lys-N ω -2-Cl-Z-N,O-dimethylhydroxyamide). Yeld: 92%. 1 H
NMR (300MHz , CDCl3): δ (ppm) 7.43-7.20 (m, 4H, CH aromatic 2-Cl-Z group), 5.19 (sb,
2H, CH 2 2-Cl-Z group), 4.99 (bs, 1H, N-Hω lysine side chain), 4.65 (sb, 1H N-Hα), 3.75 (s,
4H, N-metoxy group + CHα), 3.23-3.11 (m, 5H, N-methyl group + CH 2 lysine side chain),
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