Diisopropylethylamine → N-((2S,3R,4R,5S,6S)-3,4,5-trimethoxy-6-methyl-tetrahydropyran-2-yloxy)-malonamic acid methyl ester

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Reaction Steps

To a solution of O-((2S,3R,4R,5S,6S)-3,4,5-trimethoxy-6-methyl-tetrahydropyran-2-yl)-hydroxylamine (P-4; 157 mg, 0.71 mmol) in dichloromethane (CH2Cl2; 8 mL) was added DIEA (230 μL, 1.3 mmol) followed by a solution of methyl chloromalonate (137 mg, 1.0 mmol) dissolved in CH2Cl2 (2 mL). This mixture was allowed to stir at room temperature for 4 h. The mixture was then diluted with CH2Cl2 and washed with 1 N HCl. The aqueous fraction was extracted with CH2Cl2. The organic fractions were combined, dried with anhydrous Na2SO4 and evaporated at room temperature under vacuum. The resulting crude material was purified by silica gel chromatography (eluting with 75% EtOAc in Hexane). The title product (132 mg, 58%) was isolated as a colorless oil: 1H NMR (300 MHz, CDCl3) δ 10.00-9.38 (m, 1H), 5.06 (d, J=55.9 Hz, 1H), 4.02-2.92 (m, 18H), 1.39 (t, J=20.4 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 189.13, 101.59, 81.56, 77.24, 75.39, 69.66, 59.26, 57.89, 52.86, 39.75, 26.47, 17.85; ESIMS m/z 320 (M−H).

Provenance & Evidence