Alkylation

The complexes of iodine with linear alkyl (C1, C8, C10 , C12 , C14 and C16) dimethylamine oxides have been studied in the solvents heptane,
dichloromethane, and water. In the solvents heptane and dichloromethane and in aqueous surfactant
micelles, alkyldimethylamine oxides react with iodine to form donor-acceptor
complexes. Trimethylamine oxide is not soluble in heptane and
does not form micelles in water so no complexes were fanned in these
systems. In heptane and in dichloromethane the molecular complex ionizes
to an "inner" complex in the presence of unassociated amine oxide. The
effect of the surface activity is to reduce the concentration of free
amine oxide and suppress this ionization. In the case of trimethylamine
oxide in dichloromethane forming the dihydrate suppresses inner complex
formation. In aqueous micelles the inner complex hydrolyzes to the protonated
amine oxide, iodide ion, and hypoiodous acid which appears to oxidize
water to molecular oxygen in the presence of the amine oxide micelles.
Excess iodine complexes with iodide ion yielding triiodide ion which
forms an undissociated ion pair with the micellar protonated amine oxide.

The acid-catalyzed N-alkylation of an amide by an alcohol or an alkene
occurs successfully if the intermediate carbenium ion is highly stabilized
and therefore readily formed. This is because carbenium ion formation
must compete successfully with protonation and consequent deactivation
of the amide. The carbenium ion will N-alkylate the amide unless steric
requirements preclude such attack. In boiling glacial acetic acid acetamide is N-alkylated readily by ferrocenylmethanol, a-hydroxyethylferrocene and vinylferrocene but slowly by triphenylmethanol. Triphenylnmethylation is accelerated by a small amount of sulfuric acid. Reaction
of acetamide with diphenylmethanol in boiling glacial acetic acid yields
N-diphenylmethylacetamide in the presence of sulfuric acid, diphenylmethyl acetate in the ascence of sulfuric acid. Under both these conditions
the reaction of acetamide with benzyl alcohol fails, benzyl acetate
being the sole product. Nicotinamide is triphenylmethylated and ferrocenylmethylated only on the amide nitrogen, not on the pyridine nitrogen.
N-methylacetamide, a secondary amide, can be N-ferrocenylmethylated.