Formaldehyde → 1,2,3,4-Tetrahydro-6-hydroxy-3-isoquinolinecarboxylic acid

Temperature

90 °C

To a suspension of DL-m-tyrosine (5.00 g, 11.0 mmol) in 0.05 N HCl (50 mL) was added 37% aq. formaldehyde (5.00 mL, 5.2 g, 64.0 mmol) and the resulting slurry was heated at 90° C. for 1 h and then cooled to RT. The mixture was filtered and the resulting solid was washed with H2O and acetone and dried in vacuo to yield 6-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (3.31 g, 52% yield) as an off-white solid. MS (EI) m/z: 194.0 (M+H+). 1H NMR (400 MHz, CD3OD): δ 7.03 (d, J=8.0 Hz, 1H), 6.69 (dd, J=8.8, and 2.4 Hz, 1H), 7.00 (s, 1H), 4.28-4.19 (m, 2H), 3.80 (dd, J=11.6, and 5.2 Hz, 1H), 3.31-3.27 (m, 1H), 3.05 (dd, J=16.8, and 11.2 Hz, 1H), acid, hydroxy and amine protons not visible.

1. temperaturecooled to RT
2. filtrationThe mixture was filtered
3. washthe resulting solid was washed with H2O and acetone
4. customdried in vacuo

ORD record

ord-3aa6456e311742c4a48a84bf1ece7df0

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08163756B2