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DOI: 10.1055/s-2005-864792
Efficient Synthetic Route to Ravidosamine Derivatives
Publication History
Publication Date:
09 March 2005 (online)
Abstracts
Concise synthesis of ravidosamine, the amino sugar constituent of ravidomycin and other antibiotics, has been achieved. The key steps include (1) regioselective reduction of benzylidene acetal with DIBAL, and (2) stereoselective reduction of oxime to the corresponding amine by using samarium diiodide in the presence of methanol.
Key words
ravidosamine - regioselectivity - boron trifluoride etherate - stereoselectivity - samarium diiodide - amino sugar
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References
To a stirred solution of 9 (356 mg, 1 mmol) in CH2Cl2 (5 mL) at 0 °C was added BF3·OEt2 (0.25 mL, 2 mmol). After stirring for 5 min, the reaction was quenched with sat. aq NaHCO3 solution. The mixture was extracted with CH2Cl2, and the combined organic extracts were washed with brine, dried over Na2SO4, filtered, and concentrated. The 1H NMR indicated that the ratio of 8 and 9 was about 2:1.
18Compound 18: 1H NMR (400 MHz, CDCl3): δ = 7.40-7.26 (m, 10 H), 4.86 (d, J = 11.2 Hz, 1 H), 4.78 (d, J = 3.7 Hz, 1 H), 4.64-4.56 (m, 3 H), 4.07 (dd, J = 3.7, 11.2 Hz, 1 H), 3.85 (br q, J = 6.6 Hz, 1 H), 3.62 (br d, J = 2.9 Hz, 1 H), 3.33 (s, 3 H), 3.00 (dd, J = 2.9, 11.2 Hz, 1 H), 2.59 (s, 6 H), 1.13 (d, J = 6.6 Hz, 3 H). 13C NMR (100 MHz, CDCl3): δ = 138.2 (C), 138.1 (C), 128.2 (CH), 128.1 (CH), 128.0 (CH), 127.9 (CH), 127.5 (CH), 127.4 (CH), 97.2 (CH), 82.9 (CH), 75.2 (CH2), 75.1 (CH), 71.1 (CH2), 66.8 (CH), 61.4 (CH), 54.9 (CH3), 43.5 (CH3), 16.3 (CH3). IR (neat): 3030, 2931, 2895, 1454, 1099, 1053, 733, 696 cm-1.