Synthesis of Amines by Alkylation

As might be expected, the hybridization at nitrogen itself also drastically affects basicity, in the order jNHs R2C=NR RC=N , a phenomenon that we already enconntered in the discussion of the relative acidity of alkanes, alkenes, and alkynes (Section 13-2). Thus, iminium ions (Section 17-9) have valnes estimated to be of the order of 7 to 9 A-protonated nitriles (Section 20-8) are even more acidic (pa s -5). Table 21-2 summarizes the pAa values of the conjugate acids of some representative amines. 

Explain the decreasing values of the following (protonated) amines -NH2 nH, 

In Summary Amines are poor acids and require alkyllithium reagents or alkali metal treatment to form amide ions. In contrast, they are moderately good bases, leading to the relatively weakly acidic ammonium salts. 

Amines can be synthesized by alkylating nitrogen atoms. Several such procedures take advantage of an important property of the nitrogen in many compounds It is nucleophilic. 

As nucleophiles, amines react with haloalkanes to give ammonium salts (Section 6-2). Unfortunately, this reaction is not clean, because the resulting amine product usually undergoes further alkylation. How does this complication arise  

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