Yu, Euy Kyung published the artcileStudies on the synthesis of the 2-desamino and 2-desamino-2-methyl analogs of aminopterin intermediate at pteridine-C7 side chain, SDS of cas: 5098-14-6, the publication is Journal of the Korean Chemical Society (1993), 37(1), 131-5, database is CAplus.
Title aminopterin intermediates I (R = H, Me, NH2) were prepared from pyrazine II. Thus, dithiobisbenzoate III was reduced by NaBH4 and then treated with II to give pyrazine IV. The cyclization of IV with RC(:NH)NH2.HCl (R = H, Me, NH2) in the presence of NaOEt followed by basic hydrolysis gave I (R = H, Me, NH2).
Journal of the Korean Chemical Society published new progress about 5098-14-6. 5098-14-6 belongs to nitriles-buliding-blocks, auxiliary class Nitrile,Salt,Sulfonic acid,Amine,Benzene, name is 2-Aminomalononitrile 4-methylbenzenesulfonate, and the molecular formula is C9H9NO, SDS of cas: 5098-14-6.
Referemce:
https://en.wikipedia.org/wiki/Nitrile,
Nitriles – Chemistry LibreTexts