Hydrochloric Acid → 1,2,3,4-Tetrahydro-Beta-Carboline-3-Carboxylic Acid

Participants

Reaction Steps

L-tryptophan (10.2 g, 50 mmol), NaOH (2.0 g, 50 mmol) and H2O (20 ml) were added in a 250 ml round-bottom flask, and were stirred until the mixture became clear followed by the addition of formaldehyde (37%, 50 mmol). The mixture was stirred and reacted at room temperature for 3 h. After being refluxed for another 3 h, the mixture was poured into 200 ml cold water. While being stirred, the mixture was adjusted to pH 6 with 5N HCl. White solids were precipitated and then stored at 4° C. overnight. The white solids were filtered, washed well with water and a small amount of methanol, dried, and recrystallized with methanol to obtain white solids (9.2 g, 85%), mp 308-309° C. (reference: 309-310° C.).

Provenance & Evidence