2,2,6,6-Tetramethylpiperidine

2,2,6,6-Tetramethylpiperidine or TMP or HTMP is a clear light yellow liquid with an amine odor. This amine is used in chemistry as a hindered base because it can dissolve in organic solvents unlike ordinary bases such as potassium hydroxide.

There are many ways to synthesise TMP. One recent method starts with a conjugate addition reaction of ammonia to phorone. The intermediate triacetone amine is then reduced in a Wolff-Kishner reaction.

TMP is the starting material for an even stronger base lithium tetramethylpiperidide and the radical species TEMPO. Another non-nucleophilic base is N,N-diisopropylethylamine.