Tetrahydropapaverine hydrochloride synthesis

7synthesis methods

Product Name:Tetrahydropapaverine hydrochloride
CAS Number:6429-04-5
Molecular formula:C20H25NO4.HCl
Molecular Weight:379.8814

1-(3,4-dimethoxybenzyl)-3,4-dihydro-6,7-dimethoxyisoquinolinium chloride

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6429-04-5
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Yield:6429-04-5 89%

Reaction Conditions:

with methanol;sodium tetrahydroborate at 0 - 20; for 0.166667 h;Inert atmosphere;

Steps:

1-(3,4-Dimethoxybenzyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (6?HCl)

To a stirred suspension of crude 3,4-dihydroisoquinoline hydrochloride 12 (6.48 g) in MeOH (50 mL) wasslowly added NaBH4 (0.8 g, 21 mmol) at 0 °C under Ar. The mixture was stirred for 10 min at roomtemperature and then concentrated. After an addition of brine (16 mL) and MeCN (30 mL), the resultingmixture was partitioned between AcOEt (30 mL) and H2O (30 mL). The aqueous layer was extracted twicewith AcOEt-MeCN (30 mL, 1:1). The combined organic layers were washed with brine, dried over Na2SO4and concentrated to give yellow oil, which was dissolved in MeOH (10 mL). HCl in MeOH (5% solution,20 mL) was added to the solution, and then concentrated. The residue was crystallized by an addition ofEt2O, and the solids were filtered and washed with Et2O to give 6?HCl (4.67 g, 89% for 3 steps) as whitesolids of mp 211-215 °C. 1H NMR: 2.91 (1H, m), 3.16-3.24 (3H, m), 3.36 (1H, m), 3.56 (1H, m), 3.60 (3H, s), 3.80 (3H, s), 3.85 (6H,1316 HETEROCYCLES, Vol. 88, No. 2, 2014s), 4.73 (1H, m), 6.17 (1H, s), 6.58 (1H, s), 6.72 (1H, d, J = 8.0), 6.77-6.79 (2H, m), 9.77 (1H, br s), 10.35(1H, br s).1H NMR (D2O):9b 3.01-3.05 (2H, m), 3.16-3.29 (2H, m), 3.41 (1H, m), 3.53 (1H, m), 3.60 (3H, s), 3.72 (3H,s), 3.83 (6H, s), 4.73 (1H, m), 6.36 (1H, s), 6.73 (1H, s), 6.83-6.89 (2H, m), 7.00 (1H, m).

References:

Yamamoto, Yasutomo;Tabuchi, Yuri;Baba, Ayana;Hideshima, Kumiko;Nakano, Mai;Miyawaki, Akari;Tomioka, Kiyoshi [Heterocycles,2014,vol. 8,# 2,p. 1311 - 1321]

6957-27-3 Synthesis