Compound 3

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InChIKey LQHPINRGPQMINY-YALHFCBISA-C

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

A mixture of the compound 55 (23.7 mg, 7.40 μmol), 0.1 M NaOH_(aq) (0.488 mL, 48.8 μmol), triethylamine (0.488 mL, 3.50 mmol), and sulfur trioxide-pyridine complex (46.4 mg, 0.296 mmol) in methanol (0.6 mL) were kept stirring at room temperature for 18 h. After the starting material was completely consumed, the solvent was evaporated under reduced pressure, and the residue was finally purified by column chromatography on Sephadex LH-20 using methanol as an eluent to yield the N-sulfonated compound. A solution of the N-sulfonated compound and 20% Pd(OH)₂ on carbon (0.221 mg) in phosphate buffer (20 mM, pH = 7.0, 3 mL) was equipped with a hydrogen balloon, and the mixture was stirred at room temperature for 2 d. The whole mixture was filtered through celite, and the filtrate was concentrated in vacuo. The residue was dissolved in water (1 mL), the residue was purified through a Sephadex G-25 column eluted with water. After concentration, the residue was passed through a column of Biorad 50 X 8 Na⁺ resin using water as eluent. The product fraction was lyophilized to give the target molecule 3 (7.73 mg, 47% overall yield in two steps). ¹H NMR (600 MHz, D₂O) δ 5.58 (d, J = 3.4 Hz, 1H, H-1''), 5.36 (d, J = 3.4 Hz, 1H, H-1''''''), 5.27 (s, 1H, H-1'''''), 5.22 (s, 1H, H-1'''), 5.17 (d, J = 4.6 Hz, 1H, H-1'), 5.13 (d, J = 3.6 Hz, 1H, H-1''''), 5.11-5.10 (m, 2H, H-5', H-5'''), 5.07 (d, J = 3.5 Hz, 1H, H-1), 4.96 (s, 1H, H-5'''''), 4.68 (t, J = 9.6 Hz, 1H, H-3), 4.56 (d, J = 7.9 Hz, 1H, H-1'''''''), 4.50 (dd, J = 11.6, 3.4 Hz, 1H, H-6a), 4.39 (d, J = 11.6, 1H, H-6b), 4.36-4.34 (m, 3H, H-2', H-2''', H-2'''''), 4.29 (s, 2H, H-3''', H-3'''''), 4.26 (t, J = 3.8 Hz, 1H, H-4'), 4.15 (dd, J = 8.9, 3.8 Hz, 1H, H-3'), 4.13-4.12 (m, 1H, H-5), 4.08-4.02 (m, 4H, H-4, H-4''', H-4''''', H-2''''), 3.94-3.86 (m, 8H, H-5'', H4'''', H-6''×2, H-6''''×2, H-6''''''×2), 3.85-3.81 (m, 3H, H-4'''''', H-4''''''', H-5''''), 3.78-3.73 (m, 4H, H-3'''', H-3'''''', H-4'', H-5''''''), 3.70 (dd, J = 10.7, 3.5 Hz, 1H, H-2), 3.63 (t, J = 9.8 Hz, 1H, H-3''), 3.58-3.54 (m, 2H, H-3''''''', H-5'''''''), 3.49 (s, 3H, CH₃), 3.41 (td, J = 7.9, 3.5 Hz, 1H, H-2'''''''), 3.30-3.26 (m, 2H, H-2'', H-2''''''), 2.09 (s, 3H, CH₃); ¹³C NMR (150 MHz, D₂O) δ 175.3 (C), 174.8 (C×2), 172.1 (C), 101.9 (CH), 99.2 (CH×2), 99.1 (CH), 97.3 (CH), 95.7 (CH), 95.3 (CH), 93.7 (CH), 77.7 (CH), 77.5 (CH), 77.4 (CH), 76.9 (CH), 75.7 (CH×2), 75.67 (CH), 75.6 (CH), 75.0 (CH×2), 74.6 (CH), 74.5 (CH), 73.2 (CH), 72.7 (CH), 71.7 (CH), 71.4 (CH×2), 71.35 (CH), 70.9 (CH), 70.7 (CH), 70.6 (CH), 69.8 (CH), 69.5 (CH), 69.3 (CH), 69.1 (CH), 67.8 (CH), 67.6 (CH), 65.8 (CH₂), 63.5 (CH), 59.7 (CH₂), 59.5 (CH₂), 59.3 (CH₂), 58.1 (CH), 57.7 (CH), 55.3 (CH₃), 53.5 (CH), 53.3 (CH), 22.2 (CH₃); HR-ESI-MS (m/z): [M-9H+6Na]^3- calcd. for C₅₁H₇₃N₄O₆₃Na₆S₇, 703.6688; found, 703.6695; [M-8H+5Na]^3- calcd. for C₅₁H₇₄N₄O₆₃Na₅S₇, 696.3414; found, 696.3416; [M-7H+4Na]^3- calcd. for C₅₁H₇₅N₄O₆₃Na₄S₇, 689.0141; found, 689.0150; [M-6H+3Na]^3- calcd. for C₅₁H₇₆N₄O₆₃Na₃S₇, 681.6868; found, 681.6859; [M-5H+2Na]^3- calcd. for C₅₁H₇₇N₄O₆₃Na₂S₇, 674.3595; found, 674.3558; [M-4H+Na]^3- calcd. for C₅₁H₇₈N₄O₆₃NaS₇, 667.0321; found, 667.0350.