Nornicotine

Nornicotine is an alkaloid found in various plants including Nicotiana, the tobacco plant. It is chemically similar to nicotine, but does not contain a methyl group.

It is a precursor to the carcinogen N-nitrosonornicotine that is produced during the curing and processing of tobacco. Nornicotine can react in human saliva to form N-nitrosonornicotine, a known type 1 carcinogen.

Synthesis
There are several routes for the synthesis of nornicotine. One route is the demethylation of nicotine, which can be accomplished by reaction with silver oxide.

$$\mathrm{ \xrightarrow[H_2O]{Ag_2O} }$$

Another route is the partial reduction of 3-myosmine, which can be accomplished by standard catalytic hydrogenation conditions using palladium as a catalyst or with sodium borohydride. This reaction gives the racemic product.

$$\mathrm{ \xrightarrow[H_2]{Pd/C} }$$

Pharmacology
Nornicotine possess high affinity for alpha-6 and alpha-7 subunits of nAChRs. It also inhibits DAT in striatum via nAChR and releases dopamine in rats.