1,2,3,4-Tetrahydroisoquinoline → Racemic 4-benzothiazol-6-yl-2-methyl-1,2,3,4-tetrahydroisoquinoline

Participants

Reaction Steps

Racemic 4-benzothiazol-6-yl-2-methyl-1,2,3,4-tetrahydroisoquinoline was prepared from 6-bromo-benzothiazole by a method similar to the one described in Example 129 (Steps B to C). The desired tetrahydroisoquinoline (20.5 mg) was dissolved in methanol and treated with a solution of maleic acid in methanol (1 mL) at 0° C. The solution was stirred at room temperature overnight, then concentrated, and the solid was washed with diethyl ether providing (+/−)-4-benzothiazol-6-yl-2-methyl-1,2,3,4-tetrahydroisoquinoline, maleate salt (30 mg, 98%, >99% AUC HPLC): 1H NMR (CD3OD, 500 MHz) δ 9.28 (d, J=3.9 Hz, 1H), 8.09-8.08 (m, 1H), 8.00-7.99 (m, 1H), 7.44-7.42 (m, 1H), 7.36-7.25 (m, 3H), 6.93-6.92 (m, 1H), 6.26-6.25 (s, 2H), 4.80-4.78 (m, 1H), 4.64-4.56 (m, 2H), 3.93-3.89 (m, 1H), 3.63-3.61 (m, 1H), 3.08 (s, 3H); ESI-MS m/z=281 [M+H]+.

Provenance & Evidence