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Arginine-PNAs
foam. Yield: 30%. 1 H NMR (600MHz, CD 3 OD): δ (ppm) 7.79-7.74 (m, 2H, CH aromatic
Fmoc group), 7.72-7.70 (m, 4H CH aromatic tosyl group), 7.59-7.57 (m, 2H CH aromatic
Fmoc group), 7.36-7.33 (m, 2H, CH aromatic Fmoc group), 7.27-7.22 (m, 6H CH aromatic
Fmoc group + CH aromatic tosyl group), 4.55-44.36 (m, 2H CH 2 Fmoc), 4.25-4.15 (m, 1H
CH Fmoc), 3.36 (bs, 1H C(2)-H α), 3.30-3.29 (bs, 1H, C(5)Hα), 3.14-3.07 (m, 2H, ψ CH 2 ),
2.33-2.30 (m, 10H, CH 2 arginine side chain + CH 3 tosyl group), 1.34-1.24 (m, 17H, CH 2
arginine side chain + CH 3 Boc group). 13 C-NMR (150 MHz, CD 3 OD, the CH 3 signals of the
tosyl groups have identical chemical shifts due the pseudoequivalence of the arginine side
chains): δ(ppm) 178.1, 159.4, 158.8, 158.5, 158.4, 145.7, 145.5, 143.8, 143.0, 142.9, 142.5,
130.6, 129.2, 128.7, 127.8, 127.4, 126.4, 126.2, 121.3, 80.4, 68.8, 68.5, 64.2, 53.1, 51.2, 48.8,
42.2, 31.9, 29.2, 28.8, 28.4, 27.3, 21.8. ESI-MS (CH 3 OH, positive ions): calculated m/z:
969.4 (MNa + ), found: 969.3. HRMS (ESI + ): calcd m/z for C 46 H 58 N 8 O 10 NaS 2 (MNa + ):
969.3615, found: 969.3624.
N α -Boc-Glyψ-[D-Arg(N ω -Tosyl)] methyl ester. D-Arg-N ω -Tosyl methyl ester hydrochloride
(0.57g, 1.52 mmol) and DIPEA (0.26ml) were dissolved in methanol (20 ml) at room
temperature and the mixture was stirred for 20 minutes. Boc-Gly-aldehyde (0.24g, 1.52mmol)
was then added and the solution was stirred for 30 min. at room temperature, then cooled 0°C
and NaBH 3 CN (0.1g, 1.52mmol) and CH 3 COOH (0.096ml, 1.67mmol) were added. After 2h
the methanol was evaporated. The residue was dissolved in DCM and washed with saturated
potassium hydrogen sulphate (twice) and sodium hydrogen carbonate (twice). The combined
organic phases were dried over magnesium sulphate and filtered, and solvent was evaporated
under vacuum. The crude product was purified by flash chromatography (eluent
dicloromethane :methanol= 95:5) and obtained as white foam. Yield: 48%. 1 H-NMR
(300MHz, DMSO-d 6 ): δ(ppm) 7.64 (d, 2H, J(H,H) = 8.1 Hz, CH aromatic tosyl group), 7.29
(d, 2H, J(H,H) = 8.0 Hz, CH aromatic tosyl group), 7.03 (bs, 1H, N η -H arginine side chain),
6.72 (bs, 1H, NH-Boc), 6.56 (bs, 1H, N η -H arginine side chain), 3.61 (s, 3H, CH 3 methyl
ester), 3.34 (s, 1H, C(2)H α), 3.23-2.86 (m, 6H, CH 2 arginine side chain + Glyψ CH 2 CH 2 ),
2.35 (s, 3H, CH 3 tosyl group), 1.61-1.43 (m, 4H, CH 2 arginine side chain), 1.37 (s, 9H, CH 3
Boc group). 13 C-NMR (75 MHz, DMSO-d 6 ): δ(ppm) 174.9, 156.4, 156.2, 141.2, 140.9, 128.9,
125.4, 77.3, 60.1, 51.2, 46.9, 40.6, 29.6, 29.2, 28.3, 25.5, 21.4. ESI-MS (CH 3 OH, positive
ions): calculated m/z: 486.6 (MH + ), 508.6 (MNa + ), 524.7 (MK + ), found: 486.5, 508.5, 524.4.
N α -Boc-Glyψ-[D-Arg-(N ω -Tosyl)]-OH. N α -Boc-Glyψ-[D-Arg-((N ω -Tosyl)] methyl ester
(0.66g, 1.37 mmol) was dissolved in THF:H 2 O = 1:1 (25ml). NaOH (0.42g, 10.5mmol) was
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