β-Methylphenethylamine (β-Me-PEA, BMPEA), or 1-amino-2-phenylpropane, is an organic compound of the phenethylamine class, and a positional isomer of the drug amphetamine, with which it shares some properties. In particular, both amphetamine and β-methylphenethylamine are human TAAR1 agonists. In appearance, it is a colorless or yellowish liquid.
Relatively little information has been published about this substance. Hartung and Munch reported that it had good antihypotensive (pressor) activity in experimental animals, and that it was orally active. The MLD (minimum lethal dose) for the HCl salt was given as 500 mg/kg (rat, s.c.) and 50 mg/kg (rabbit, i.v.).
A study by Graham and co-workers at the Upjohn Co., comparing a large number of β-methylphenethylamines substituted on the benzene ring showed that β-methylphenethylamine itself had 1/700 x the pressor activity of epinephrine, corresponding to ~ 1/3 the potency of amphetamine. The β-methyl compound also had ~ 2 x the broncho-dilating power of amphetamine (as measured using the isolated rabbit lung), and an LD50 of 50 mg/kg (rat, i.v.).
β-Methylphenethylamine has been synthesized by the catalytichydrogenation of 2-phenylpropionitrile with Pd on charcoal, in absolute ethanol containing 3 equivalents of HCl; the base was isolated in the form of its HCl salt, m.p. 123-124°.
In 2015, 52% of supplements labeled as containing Acacia rigidula were found to contain BMPEA. Consumers following recommended maximum daily servings would consume a maximum of 94 mg of BMPEA per day. In 2012, however, the FDA determined that BMPEA was not naturally present in Acacia rigidula leaves.
^Wainscott DB, Little SP, Yin T, Tu Y, Rocco VP, He JX, Nelson DL (2007). "Pharmacologic characterization of the cloned human trace amine-associated receptor1 (TAAR1) and evidence for species differences with the rat TAAR1". The Journal of Pharmacology and Experimental Therapeutics320 (1): 475–85. doi:10.1124/jpet.106.112532. PMID17038507. The effect of β-carbon substitution on the phenylethylamine side chain was also investigated (Table 3). A β-methyl substituent was well tolerated compared with β-PEA. In fact, S-(–)-β-methyl-β-PEA was as potent as β-PEA at human TAAR1.
^ abHartung WH, Munch JC (1931). "Amino alcohols. VI. The preparation and pharmacodynamic activity of four isomeric phenylpropylamines". J. Am. Chem. Soc.53 (5): 1875–9. doi:10.1021/ja01356a036.
^Graham BE, Cartland GF, Woodruff EH (1945). "Phenyl propyl and phenyl isopropyl amines. Changes in pharmacological action on substitution of phenyl nucleus and amino nitrogen". Ind. Eng. Chem.37 (2): 149–51. doi:10.1021/ie50422a010.