Raj Sinha, Deo published the artcileNaphthyridines reactivity of methyl groups: new cyanine dyes from 2,7-dimethyl- and 4,7-dimethyl-1,8-naphthyridines, Quality Control of 14903-78-7, the publication is Journal of the Indian Chemical Society (1979), 56(2), 164-7, database is CAplus.
The reactivity of the 4-Me in 4,7-dimethyl-1,8-naphthyridine (I) [14759-23-0] is greater than the 7-Me towards condensation with m-nitrobenzladehyde [99-61-6]. Cyanine and styryl dyes derived from I and from 2,7-dimethyl-1,8-naphthyridine [14903-78-7] were prepared and their structures established. The trimethine dyes were found to be useless as sensitizers for Ag halide emulsions.
Journal of the Indian Chemical Society published new progress about 14903-78-7. 14903-78-7 belongs to naphthyridine, auxiliary class 6.6_Aromatics,Naphthyridines, name is 2,7-Dimethyl-1,8-naphthyridine, and the molecular formula is C10H10N2, Quality Control of 14903-78-7.
Referemce:
https://en.wikipedia.org/wiki/1,8-Naphthyridine,
1,8-Naphthyridine | C8H6N2 – PubChem