Chemical Properties
2-Pentylpyridine has a tallowy-like odor.
Occurrence
Reported as occurring in shallow-fried beef and as a steam-volatile component in roasted Spanish peanut.
Also reported found in bell pepper, black sesame seeds, roast turkey, fried chicken, fried beef, cooked beef, mutton, lamb fat, roasted
filberts, toasted oats and coriander seed.
Uses
flavors and fragrances
Definition
ChEBI: 2-Pentylpyridine is a member of pyridines.
Preparation
By alkylation of 2-pycollyl lithium; by hydrogenation of 2-pentenyl pyridine.
Aroma threshold values
Detection: 0.6 ppb. Aroma characteristics at 0.1%: strong fresh green vegetative, peppery, mushroom,
herbal and oily.
Taste threshold values
Taste characteristics at 1 ppm: green pepper vegetative, mushroom-like, musty, oily, meaty and MSG-like.
Synthesis
GENERAL STEPS: A THF solution (3 mL) of MnCl2-(THF)1.6 (3 mol%, 3 mg, 0.012 mmol) was added to a 20 mL scintillation vial in an inert atmosphere glove box. Subsequently, 2-chloropyridine (0.41 mmol, 1 eq.) was added as an electrophilic reagent, as well as the internal standard homotrimethylbenzene (0.41 mmol, 1 eq.). After stirring for 5 minutes at room temperature, 1-pentylmagnesium chloride Grignard reagent solution (1.2-2.6 eq.) was slowly added dropwise and the reaction continued to be stirred at room temperature. Upon completion of the reaction, the mixture was removed from the glove box and the reaction was quenched with saturated K2CO3 solution (3 mL) and EtOAc (3 mL). The organic layer was separated and the aqueous phase was further extracted with EtOAc (3 x 3 mL). The combined organic phases were dried with MgSO4, filtered and concentrated. The crude product was purified by silica gel column chromatography to afford the target product 2-pentylpyridine.
Purification Methods
Dry it with NaOH for several days, then distil it from CaO under reduced pressure, taking the middle fraction and redistilling it. The picrate has m 72-72.8o (from EtOH). [Beilstein 20 III/IV 2835.] 3-n-Pentylpyridine, purified as the 2-isomer, has b 110-112o/20mm, 224-226o/748mm, and the picrate has m 79.5-80o(from EtOH). [Beilstein 20 III/IV 2835.]
References
[1] Synlett, 2018, vol. 29, # 13, p. 1700 - 1706
