Strata xl c 100 μm solid phase extraction column

Synthesis of compound 1 (1-[2-(4-hydroxyphenyl)ethyl]-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) was adapted from a previously described protocol.⁴⁰ 151 mg of 3-(4-hydroxyphenyl)propanal (also referred to 4-hydroxydihydrocinnamaldehyde, or 4-HDCA; Small Molecules, Inc.) and 144 mg of dopamine (Millipore Sigma) in 4 mL of 1:1 ACN to potassium phosphate buffer (0.1 M, pH = 6.0) was stirred at 50 °C for 14 hours. After this incubation, 3 volumes of dichloromethane (DCM) were added to the mixture. The mixture was then extracted several times with Milli-Q water. The aqueous fractions were combined and acidified to pH = 3.0. The mixture was then purified with a Strata-XL-C 100 μm solid phase extraction column (500 mg/3 mL, Phenomenex). 6.8 mg of putative 1 was obtained, and the structure was verified by ¹H NMR using a 400 MHz NMR spectrometer (Varian).
1-[2-(4-hydroxyphenyl)ethyl]-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (1): ¹H NMR (400 MHz, Methanol-d₄) δ 7.05 (d, J = 8.5 Hz, 2H), 6.70 (d, J = 8.4 Hz, 2H), 6.56 (s, 1H), 6.51 (s, 1H), 3.94 (q, J = 3.8 Hz, 1H), 3.28-3.22 (m, 1H), 3.00-2.93 (m, 1H), 2.83 – 2.55 (m, 4H), 2.14-1.94 (m, 2H). (Supplementary Information Fig. 6)