Rewcastle, Gordon W.; Denny, William A.; Winters, R. Thomas; Colbry, Norman L.; Showalter, H. D. Hollis published the article 《Synthesis of 6-substituted pyrido[3,4-d]pyrimidin-4(3H)-ones via directed lithiation of 2-substituted 5-aminopyridine derivatives》. Keywords: pyridopyrimidinone preparation; pyrimidinone pyrido preparation; aminopyridine lithiation carboxylation.They researched the compound: 5-Amino-2-fluoropyridine( cas:1827-27-6 ).Synthetic Route of C5H5FN2. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:1827-27-6) here.
Directed lithiation of Boc or pivaloyl derivatives of 2-substituted 5-aminopyridines I (R = Cl, F, OMe, R1 = COnCMe3, X = H, n = 1, 2) with BuLi-TMEDA in di-Et ether at -10°C gave 4-lithio derivatives which were quenched with CO2 to give the analogous C-4 carboxylic acids I (X = CO2H). Hydrolysis of the protecting groups with either TFA or aqueous KOH gave 2-substituted 5-aminopyridine-4-carboxylic acids I (R1 = H, X = CO2H) which were converted to 6-substituted pyrido[3,4-d]pyrimidin-4(3H)-ones II by reaction with formamide or, more optionally, formamidine acetate. Boc protected aminopyridines provided the best overall results, with synthesis of these derivatives best achieved by direct reaction of the aminopyridine with di-tert-Bu dicarbonate in the absence of added base.
Although many compounds look similar to this compound(1827-27-6)Synthetic Route of C5H5FN2, numerous studies have shown that this compound(SMILES:NC1=CN=C(C=C1)F), has unique advantages. If you want to know more about similar compounds, you can read my other articles.