Author Topic: Phenylalkylamines & Mannich Bases  (Read 9189 times)

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Phenylalkylamines & Mannich Bases
« on: January 16, 2003, 09:35:00 PM »
Synthesis of Mannich Bases Using Substituted Aromatic Alcohols with Secondary Amines:
Relative Reactivity and Regioselectivity Depending on Substrates

Ki-Whan Chi , Yoon Soo Ahn, Tae Ho Park , Jeong Soo Ahn, Hyun Ah Kim, Joo Yeon Park

Journal of the Korean Chemical Society 45(1), 51-60 (2001)


One-pot Mannich reaction of substituted hydroxy aromatic compounds with secondary amines in an aprotic solvent has been studied. The results demonstrate that the relative reactivity and regioselectivity of the Mannich reaction depend on the steric hindrance of amines as well as the nucleophilicity of hydroxy aromatic rings.


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Synthesis of PEAs from Phenylacetonitriles
« Reply #2 on: September 15, 2004, 07:23:00 AM »
Synthesis of Phenethylamines from Phenylacetonitriles
Obtained by Alkylation of Cyanide Ion with Mannich Bases from Phenols and Other Benzylamines

J. H. Short, D. A. Dunnigan and C. W. Ours

Tetrahedron 29, 1931-1939 (1973)


Benzylamines, obtained by the Mannich reaction on phenols or by reductive alkylation of aldehydes, have been used in place of benzyl chlorides to alkylate cyanide ion to obtain nitriles which may be reduced to phenethylamines. Yields of 4-hydroxy-3-methoxyphenylacetonitrile were about the same from the primary, secondary, and tertiary amines. Benzylamines not having either an ortho or para OH group did not function as alkylating agents. With such compounds it was necessary to prepare the quaternary salts before alkylation could be achieved. 6-Hydroxydopamine was prepared from 2,4,5-trimethoxybenzaldehyde utilizing the latter approach. 3,5-Dimethoxy-4-hydroxyphenethylamine was cyclized to the corresponding dihydroisoquinoline. The isoquinoline and tetrahydroisoquinoline analogs were also prepared. 4-Hydroxy-3-methoxyphenylacetonitrile was hydrolysed to homovanillic acid, the naturally occurring metabolite of dopamine.