Hindered Amines. Synthesis of Hindered Acyclic α-Aminoacetamides

Article abstract of DOI:10.1021/jo01306a025

Hindered amines and their nitroxyl radicals are useful in spin-label studies as nonnucleophilic bases and as stabilizers for polymers against UV degradation.Hindered acyclic α-aminoacetamides (3, R5 = aryl, tert-butyl; R6 = H) can be synthesized from amines, ketones, and chloroform with 50percent sodium hydroxide solution in phase-transfer-catalyzed reactions.Nucleophilic secondary amines will undergo the same reactions while bulky ones fail.Mixed 3 can be prepared from different amines according to their nucleophilicities. 1,1-Dialkyl-2,2-dichlorooxirane (5) is believedto be the reactive intermediate.Imines are sometimes formed as byproducts through the opening of a carbon-carbon bond in the oxirane ring by amines.Thus, tert-butylcyclohexylamine (7) is obtained in 62percent yield after hydrogenation of the crude imine from tert-butylamine, cyclohexanone, and chloroform.