4802-88-4Relevant academic research and scientific papers
Alkali metal cations control over nucleophilic substitutions on aromatic fused pyrimidine-2,4-[1H,3H]-diones: Towards new PNA monomers
Li, Pengfa,Zhan, Chuanlang,Zhang, Shanlin,Ding, Xunlei,Guo, Fengqi,He, Shenggui,Yao, Jiannian
, p. 8908 - 8915 (2012/10/29)
In this paper we report synthesis of a series of aromatic fused pyrimidine-2,4(3H)-dione-1-yl acetic acid and new PNA monomers containing these polycyclic nucleobase analogues. Introduction of a fused aromatic ring onto the 5,6-positions of the pyrimidine-2,4-[1H,3H]-diones brings about the steric effects and the charge delocalization, both weakening the nucleophilic substitutions on the 1- and 3-positions. We found that alkali metal cations play an important role in this alkylation reaction. LiOH brings out a much more efficient alkylation than NaOH does, while KOH nearly does not work on this reaction. Such influences from the alkali metal cations are probably due to that the charge-pairing interactions between the pyrimidine-2,4-dioxide anions and the alkali metal cations rearrange the charge distribution around the whole aromatic system and increase the negative charge distribution on the 1- and 3-nitrogen atoms, which then strengthens the nucleophilic reactivity on these positions.
Quinazoline Carboxylic Acids, Part X. Synthesis of 1-Methyl-2,4-dioxo-quinazolin-3-yl-acetic Acid, 2,4-Dioxo-quinazolin-1-yl-acetic Acids, 2,4-Dioxo-1,3-quinazolinediacetic Acids and Their Esters
Suesse, Manfred,Johne, Siegfried
, p. 71 - 80 (2007/10/02)
2,4-Dioxo-quinazolin-1-yl-acetic acid esters (2) were prepared by the reaction of either 3,1-benzoxazine-2,4-diones (1) with urea in the melt or in solution or of the substituted anthranilic acid ester 4 with potassium cyanate in acid solution.The anthran
