Schneller, S. W. published the artcileA simple synthesis of thieno[2,3-b]pyrazine and thieno[2,3-b]pyridine, SDS of cas: 59944-75-1, the publication is Journal of Heterocyclic Chemistry (1976), 13(2), 273-5, database is CAplus.
The thienopyrazines I and -pyridines II (R = R1 = H) were prepared by diazotizing the amino derivatives I and II (R = NH2, R1 = CO2Et), resp., saponifying the resulting carboxylates I and II (R = H, R1 = CO2Et), resp., and decarboxylating the resulting carboxylic acids with Cu.
Journal of Heterocyclic Chemistry published new progress about 59944-75-1. 59944-75-1 belongs to pyrazines, auxiliary class Other Aromatic Heterocyclic,Amine, name is Thieno[2,3-b]pyrazin-7-amine, and the molecular formula is C6H5N3S, SDS of cas: 59944-75-1.
Referemce:
https://en.wikipedia.org/wiki/Pyrazine,
Pyrazine | C4H4N2 – PubChem