Hydrochloric Acid → 2-(2-Naphthyl)ethyl-amine

Participants

Reaction Steps

Arylethylamines that were not commercially available were made by the following procedure. 2-Naphthylacetonitrile Compound 3-2 (16.7 g, 0.10 mol) in anhydrous tetrahydrofuran (50 mL) was added to 1M solution of BH3-THF (250 mL, 0.25 mol) over 10 min at room temperature. The reaction proceeds with an induction period of 2-4 min. Following the addition, the mixture was heated under reflux and under argon for one hour (TLC of a quenched aliquot showed no starting material). The reaction was cooled in an ice bath and 10% aqueous HCl (150 mL) was added with caution over a 30 min period (vigorous reaction with the first few drops). Following the addition concentrated hydrochloric acid (100 mL) was added and the mixture brought up to reflux for 30 min. The reaction was cooled in an ice bath and extracted once with ethyl ether. The aqueous layer was carefully brought to pH 12 with 40% sodium hydroxide solution (use of concentrated base allows for smaller volumes of the aqueous layer and simplifies the extraction of the amine) and extracted with diethyl ether (4×250 mL). The organic layer was washed with brine (50 mL), dried over sodium sulfate, and evaporated at reduced pressure below 40° C. The solvent was not completely removed to avoid loss of product. TLC (85:15 CHCl3/MeOH, Rf=0.1) shows that the amine is essentially pure. Oxalic acid (9.0 g, 0.10 mole) was dissolved in methanol (10 mL) and added to the crude amine diluted with diethyl ether to a 300 mL volume. The white precipitate was collected by filtration, washed with ether, and dried in vacuo to provide Compound 3-3 (22.3 g, 85%) as the oxalate salt (mp=191-193° C.). Anal Calcd. for C12H13N-0.85 C2O4H2: C, 66.42; H, 5.98. Found: C, 66.67; H, 6.05. Compound 3-3 freebase: 1H NMR (300 MHz, CDCl3) δ 7.83-7.77 (m, 3H), 7.65 (s, 1H), 7.49-7.40 (m, 2H), 7.34 (d of d, J=8.5 and 1.6 Hz, 1H), 3.06 (t, J=7 Hz, 2H), 2.92 (t, J=7 Hz, 2H).

Provenance & Evidence