Hydrochloric Acid → 4-(2-Methylbenzo[b]thiophen-5-yl)-2-methyl-1,2,3,4-tetrahydroisoquinoline

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Reaction Steps

4-(2-methylbenzo[b]thiophen-5-yl)-2-methyl-1,2,3,4-tetrahydroisoquinoline was prepared from 5-bromo-2-methylbenzothiophene and isoquinolin-4-ylboronic acid as described in Example 40 (Steps C to E). The free base was dissolved in ethyl acetate and treated with 2 M hydrogen chloride in diethyl ether (2 equiv) to give the corresponding hydrochloride salt (0.41 g, 98.8% AUC HPLC): 1H NMR (300 MHz, DMSO-d6) δ 11.09 (br s, 1H), 7.88 (d, J=8.4 Hz, 1H), 7.63 (s, 1H), 7.09-7.27 (m, 5H), 6.76 (d, J=7.5 Hz, 1H), 4.69 (dd, J=10.8, 6.3 Hz, 1H), 4.55 (br s, 2H), 3.54-3.83 (m, 2H), 2.94 (s, 1H), 2.57 (s, 3H); EI MS m/z=293 [C19H19NS]+. Anal. Calcd. for C19H20ClNS: C, 68.61; H, 6.10; N, 4.21 with 0.73% H2O. Found: C, 68.35; H, 6.55; N, 4.00.

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