T. Scott
Apr 1, 1967
Citations
0
Influential Citations
12
Citations
Journal
Phytochemistry
Abstract
Abstract [2,3,7-14C] Nicotinic acid, prepared from [U-14C] aniline hydrogen sulphate, was administered to tobacco plants via the roots in hydroponic culture. Radioactive nicotine was isolated from the plant and purified as the dipicrate. The dipicrate was converted into nicotine, which was oxidized to nicotinic acid. The nicotinic acid was degraded stepwise to give the radioactivity of each carbon atom. A feature of this degradation is the rapid hydrogenation of nicotinic acid with rhodium on charcoal as the catalyst; there is a 50 per cent simultaneous decarboxylation to give hexahydronicotinic acid, piperidine and CO2. Radioactivity was detected and measured in positions 2 and 3 of the nicotinic acid, with negligible activity in positions 4, 5 and 6. This shows that the pyridine ring of nicotinic acid does not become symmetrical during its conversion into nicotine; the attachment of the pyrrolidine moiety occurs only at the site from which the carboxylic acid group is lost, i.e. at position 3.