Metirosine

Metirosine (α-Methyltyrosine, Metyrosine, AMPT) is an antihypertensive drug. It inhibits the enzyme tyrosine hydroxylase and, therefore, catecholamine synthesis, which, as a consequence, depletes the levels of the catecholamines dopamine, adrenaline and noradrenaline in the body.

Clinical use
Metirosine has been used in the treatment of pheochromocytoma. It is contra-indicated for the treatment of essential hypertension.

However it is now rarely used in medicine, and its main use is in scientific research, to investigate the effects of catecholamine depletion on behaviour.

Chemistry
Metyrosine, (−)α-methyltyrosine, is synthesized in a few different ways, the simplest of which is the synthesis from 4-methoxyphenylacetone, which is reacted with potassium cyanide in the presence of ammonium carbonate to give the hydantoin. Treating this with hydrogen iodide removes the methyl-protecting group on the phenyl hydroxyl group and the product is hydrolyzed by barium hydroxide into a racemic mixture of α-methyl-D,L-tyrosine, from which the desired L-isomer is isolated.
 * K. Potts, J. Chem. Soc., 1632 (1955).
 * G.A. Stein, I.K. Pfister, (1959).
 * G.A. Stein, I.K. Pfister, (1959).
 * G.A. Stein, I.K. Pfister, (1959).