Ethyl 2-(6-bromo-1-ethyl-1,3,4,9-tetrahydro-8-isopropylpyrano[3,4-b]indol-1-yl)acetate → 2-(6-Bromo-1-ethyl-1,3,4,9-tetrahydro-8-isopropylpyrano[3,4-b]indol-1-yl)ethanol

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Reaction Steps

To a stirred solution of ethyl 2-(6-bromo-1-ethyl-1,3,4,9-tetrahydro-8-isopropylpyrano[3,4-b]indol-1-yl)acetate (6.0 g, 0.015 mol) in THF (120 ml), was added 2.0 M solution of LiBH4/THF (20 ml, 0.30 mol) via syringe during 30min under a nitrogen atmosphere at room temperature. The mixture was refluxed for 10 hr, cooled, quenched with water and 5% HCl, and extracted with EtOAc. The organic phases were combined and washed with brine, dried over MgSO4, and evaporated to give a residue, which was chromatographed on silica gel. Elution with hexane-EtOAc (7:3) gave the product (4.3 g, 80%). 1H NMR (300 MHz, CDCl3) δ 8.18 (b, NH), 0.92 (t, 3H), 1.35 (d, 6H), 1.98 (m, 3H), 2.19 (m, 1H), 2.54 (t, 1H), 2.75 (m, 2H), 3.17 (m, 1H), 3.71 (t, 1H), 4.03(m, 2H), 7.13 (dd, 1H), 7.45 (d, 1H), 7.96 (b, NH). ESI (+) MS m/e=367 (MH+), ESI (−) MS m/e=365 (MH−).

Provenance & Evidence