Pyrrolidines are amphetamines with a pyrrolidine group. They are predominantly of either the pyrrolidine or the tropane types. The cycloaddition step formed two rings, including a pyrrolidine, and two stereocenters. Their piperidine, pyrrolidine, or similar rings are stable. Pyrrolidine dithiocarbamate is jargon for various salts containing the pyrrolidine dithiocarbamate anion CHNS. This dressing is made up of synthetic polymers such as methacrylate and polyvinyl pyrrolidine. In addition to pyrrolidine itself, many substituted pyrrolidines are known. The conversion of nicotine to NNK entails opening of the pyrrolidine ring. Thus, reaction of the intermediate with pyrrolidine gives dienamine (5). Pyrrole can also be formed by catalytic dehydrogenation of pyrrolidine. Displacement of halogen with pyrrolidine affords the alkylation product. C-4 and C-5 on the pyrrolidine ring. The sequence starts with the alkylation of pyrrolidine nitrogen in (1) with 2-bromoethylamine. No free pyrrolidine will be detected in the urine. But they do provide very powerful alternatives to the traditional pyrrolidine systems.