Mechanism of the mannich reaction involving 2,4-dimethylphenol and morpholine

✍ Scribed by J.H. Burckhalter; J.N. Wells; William J. Mayer

• Book ID: 104223619
• Publisher: Elsevier Science
• Year: 1964
• Tongue: French
• Weight: 262 KB
• Volume: 5
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)90479-9

✦ Synopsis

The Mannich reaction plays an essential role in the biosynthesis2 and laboratory synthesis of important nitrogenous substances. 3 In spite of the importance of the reaction, a satisfactory mechanism has not been elucidated. Several different mechanisms probably operate, depending upon pH and the nature of the active hydrogen reactant, A-H: A-H + HCHO + HNR2 -7 A-CX2NR2 + H20 Kinetic studies involving methylmalonic acid as A-H were carried out by Alexander and Underhill, while Cummings and Shelton similarly studied cyclohexanone. 5 The exact nature of rate determining reactants was not established in either case. The present report describes a kinetic study of the Mannich reaction . involving 2,4-dimethylphenol. Earlier, we postulated a quasi six-membered ring in explanation of preponderant ortho aminomethylation in phenols with the para and one ortho position open. f5,7 The same type of postulated transition state (II) has been established by the present study as an essential step in the reaction between 2,4-dimetbylphenol, formaldehyde and morpholine.