Tetrabutylammonium Fluoride → 7-Methoxy-3,3-dimethyl-2-(3,4,5-trimethoxy-benzyl)-1,2,3,4-tetrahydro-isoquinolin-6-ol

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Reaction Steps

TBAF deprotection of 227 (in analogy to the synthesis of 228) afforded the title compound (95 mg, 71%) as a yellow oil that crystallised on trituration with DCM/hexane to afford a yellow powder. mp=143-147° C. 1H NMR (270 MHz; CDCl3) 1.17 (6H, s, 2×CH3), 2.66 (2H, s, CH2), 3.52 (2H, s, CH2), 3.60 (2H, s, CH2), 3.82 (3H, s, OCH3), 3.83 (6H, s, 2×OCH3), 3.84 (3H, s, OCH3), 5.44 (1H, brs, OH), 6.50 (1H, s, CH), 6.53 (1H, s, CH), 6.60 (2H, s, 2×CH). 13C NMR (100 MHz; CDCl3) 23.82 (CH3), 42.41 (CH2), 50.02 (CH2), 52.53 (C), 53.78 (CH2), 55.88 (OCH3), 56.05 (OCH3), 60.84 (OCH3), 105.02 (CH), 110.68 (CH), 111.73 (CH), 125.62 (C), 126.85 (C), 136.44 (C), 143.54 (C), 145.02 (C), 153.08 (C). LC/MS (ES−) tr=1.17 min, m/z 386.26 (M−H)−. HRMS (ES+) calcd. for C22H30NO5 (M++H) 388.2118, found 388.2111. HPLC tr=2.73 min (>82%).

Provenance & Evidence