Description
5-Methylquinoxaline has a burnt, roasted, nutty, roasted com, coffee
odor.
Chemical Properties
5-Methylquinoxaline has a burnt, roasted, nutty, roasted corn, coffee odor
Chemical Properties
Amber liquid
Occurrence
Reported found in coffee and roasted almonds
Uses
5-Methylquinoxaline was used in the synthesis of 1,12-diphenyl-5-methyl-1,12,12a,12b-tetrahydrobis[1,2,4]triazolo[4,3-a:3′,4′-c]quinoxaline bis-cycloadducts.
Definition
ChEBI: A quinoxaline derivative in which the quinoxaline (1,4-naphthyridine) skeleton is substituted at C-5 with a methyl group.
Taste threshold values
Taste characteristics at 2 ppm: nutty, roasted, peanut and pyrazine-like with yeasty, corn-chip nuance.
General Description
5-Methylquinoxaline has been identified as one of the key volatile aroma compounds in roasted almonds{170] and roasted coffee.
Synthesis
General method: 2,3-Diaminotoluene (2.0 mmol) was mixed with compound (CAS:131543-46-9, 2.0 mmol) and sulfated polyborate (10 wt%) was added. The reaction mixture was placed in an oil bath and the reaction was stirred at 100 °C. The reaction progress was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was cooled to room temperature and the reaction was quenched with deionized water. Subsequently, the mixture was filtered or extracted with ethyl acetate (EtOAc) to isolate the product. The crude product can be purified by ethanol recrystallization or by column chromatography using silica gel as stationary phase with ethyl acetate: petroleum ether (EtOAc:pet) as mobile phase. The final product is the known compound 5-methylquinoxaline, which was identified by determining its melting point and 1H NMR and 13C NMR spectra, and the resulting spectral data were confirmed by comparing them with literature values.
References
[1] Journal of Chemical Sciences, 2017, vol. 129, # 2, p. 141 - 148
[2] Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1982, p. 357 - 364
[3] Organic Magnetic Resonance, 1980, vol. 14, # 4, p. 300 - 304
[4] Organic Process Research and Development, 2003, vol. 7, # 3, p. 318 - 323
