Kubota, Etsuro published the artcileOxazoles and pyrazines identified in roasted green tea aroma, Recommanded Product: 4,5-Dimethyloxazole, the publication is Chagyo Gijutsu Kenkyu (1983), 59-61, database is CAplus.
From the basis fraction of roasted green tea, 2 oxazoles, 14 alkylpyrazines, 3 cyclopentapyrazines, and 4 furan compounds were separated The 2 oxazoles were identified as 4,5-dimethyloxazole  [20662-83-3] and 2,4,5-trimethyloxazole  [20662-84-4] by gas chromatog.-mass spectrometry. Alkylpyrazines constituted â?0% of the volatiles in the basic fraction.
Chagyo Gijutsu Kenkyu published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Recommanded Product: 4,5-Dimethyloxazole.
Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem