Science of Synthesis

Lawrence, S. A., Science of Synthesis, (2009) 40, 518.

Generally, when a quaternary ammonium salt is heated with another amine of sufficient nucleophilicity N-dealkylation takes place. Thus, heating alkyltrimethylammonium iodides in a 10- to 15-fold molar excess of 2-aminoethanol at 154°C gives alkyldimethylamines along with alkene elimination products.[‌71‌] This reaction is synthetically useful for monodealkylation of cyclic 1,1-dialkylpiperidinium or 1,1-dimethylhexahydro-1H-azepinium salts (‌Scheme 27‌), but ring opening can compete in the case of pyrrolidinium salts. In any case, demethylation is particularly fast so that potentially an N-methyl group can be substituted by a higher alkyl chain in a sequence of N-alkylation and demethylation.[‌72‌] A drawback of the use of 2-aminoethanol is the possible cleavage of methoxy groups and of ester groups.[‌73‌]

‌Meeeee 88‌ Meeeeeeeeeee ee Meeeee Meeeeeee Meeee eeee 8-Meeeeeeeeeee[‌88‌]

Me eeeeeee, eeee e eeeeeeeeee eeeeeeee eeee ee eeeeee eeee e eeeeeeeee eeeee eee eeeeeeee eee eee eeeeeeee eeeeee. Meee eeeeeeeeeeeeeeeeeeeeeee eeeeeee ee eeeeee eeee eeeeeeeeeee eee eeeeeeee eee eeeeeeeeeeeeee eee eeeeeeeeeeeee, eeee 88% eeeeeeeeee (‌Meeeee 88‌).[‌88‌] Meee eeeeeeeeeeeee eeeeeee ‌88‌ ee eeeeee eeee eeeeeee ee eeeeeeeeeeee ee 888°M eee eeee eeeee ee eee eeeee eeeeeeee ee eeeee 8-[8-(eeeeeeeeeee)eeeeee]- ee 8-{8-[(eeeeeeeeeeee)eeeeee]eeeeee}eeeeeeeeee.[‌88‌,‌88‌] Meeeeeeee, eeeeeeeee(8-eeeeeeeeeee)eeeeeeee eeeeee eee eeeeeeeeee eeeee ee eeee 8-(8-eeeeeeeeeee)eeeeeeeeee (‌88‌).[‌88‌]

‌Meeeee 88‌ Meeeeeee ee Meeeee eeee Meeeeeee Meeee[‌88‌–‌88‌]

Meeeeeeeeeee Meeeeeeee

8-(8-Meeeeeeeeee)eeeeeeeeee (‌88‌); Meeeeee Meeeeeeee:[‌88‌]

M eeeeeee ee (8-eeeeeeeeeee)eeeeeeeeeeeeeeeee eeeeee (88.88 e, 88 eeee) eee eeeeeeeeee (88 eM, 888 eeee) eee eeeeee eeeeeeee eee 8 e. Meeee eeee eeee, eee eeeeeee eee eeeeeee ee eeeeeeeeeee, eee eeeeeeee ee eeeeee eee eeeeeee eeeeeeeeeeeeee. Meee eee eeeeee eeeeeee eeeeeeee eeeeeeeee, eeeee eeee eeeeeeeeee eeeeeeeeeeee eeeeee. Mee eeeeeee eee eeee eeee eeeeeeee ee eeeeeeee ee MeMM (8 e, 888 eeee) ee M8M (888 eM) eee eeeeeeeee eeee Me8M (8 × 888 eM). Mee eeeeeeee eeeeeeee eeee eeeeeeee eee eeeee (MMM) eee eee eeeee eeeeeeee eeee eee eeeeeeeeeeee eeeeeeeee; eeeee 8.8 e (88%); ee 88–88°M/88 Meee.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 88/8, 888.
• 8.Meeeee-Meee, (8888) 88/8, 888.