 | |
| Names | |
|---|---|
| Preferred IUPAC name 1-Methylpyridin-1-ium-3-carboxylate | |
| Other names Nicotinic acidN-methylbetaine Coffearine Caffearine Gynesine Trigenolline | |
| Identifiers | |
| |
3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
|
| ECHA InfoCard | 100.007.838 |
| UNII | |
| |
| |
| Properties | |
| C7H7NO2 | |
| Molar mass | 137.138 g·mol−1 |
| Melting point | 230 to 233 °C (446 to 451 °F; 503 to 506 K) (monohydrate)[contradictory] 258–259 °C (hydrochloride) |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Trigonelline is analkaloid withchemical formulaC7H7NO2. It is azwitterion formed by themethylation of the nitrogen atom ofniacin (vitamin B3). Trigonelline is a product of niacin metabolism that is excreted in the urine of mammals.[1]
Trigonelline occurs in many plants. It has been isolated from the Japaneseradish[2] (Raphanus sativus cv. Sakurajima Daikon),fenugreek seeds (Trigonella foenum-graecum, hence the name),[3] garden peas, hemp seed, oats,[4] potatoes,Stachys species,dahlia,[5]Strophanthus species,[6] andDichapetalum cymosum.[7] Trigonelline is also found incoffee.[8] Higher levels of trigonelline are found inarabica coffee.
Holtz, Kutscher, and Theilmann have recorded its presence in a number of animals.[9]
Trigonellinecrystallizes as a monohydrate fromalcohol in hygroscopic prisms (m.p. 130 °C or 218 °C [dry, dec.]). It is readily soluble in water or warm alcohol, less so in cold alcohol, and slightly so inchloroform orether. The salts crystallize well, the monohydrochloride, in leaflets, sparingly soluble in dry alcohol. Thepicrate forms shining prisms (m.p. 198−200 °C) soluble in water but sparingly soluble in dry alcohol or ether. The alkaloid forms several aurichlorides: the normal salt, B•HCl•AuCl3, is precipitated when excess ofgold chloride is added to the hydrochloride, and, after crystallization from dilute hydrochloric acid containing some gold chloride, has m.p. 198 °C. Crystallized from water or very dilute hydrochloric acid, slender needles of B4•3 HAuCl4 (m.p. 186 °C) are obtained.
When trigonelline is heated in closed tubes withbarium hydroxide at 120 °C, it gives rise tomethylamine, and, if treated similarly with hydrochloric acid at 260 °C createschloromethane andnicotinic acid (a form of vitamin B3). Trigonelline is a methylbetaine of nicotinic acid.[10]
