Reductones and tricarbonyl compounds XXI. Reactions of dehydroascorbic acid and of other 2,3-dioxobutyrolactones with o-phenylenediamine was written by Dahn, H.;Moll, H.. And the article was included in Helvetica Chimica Acta in 1964.Category: pyrazines This article mentions the following:
2,3-Dioxo-γ-lactones react with ο-C6H4(NH2) 2 at both oxo groups and also at the lactone CO groups. Structures of condensation products were investigated. Reaction of 2 g. 4-phenyl-2,3-dioxobutyrolactone hydrate (Ia) in 200 ml. 6N HCl at room temperature with 3 g. ο-C6H4-(NH2)2 yields 96% 3-(α-hydroxybenzyl)quinoxaline-2-carboxylic acid lactone (IIa), m. 184° (aqueous Me2CO). A suspension of 700 mg. IIa in 25 ml. MeOH is saturated at room temperature with NH3 to yield 97% the corresponding amide, m. 152-3° (aqueous MeOH), which is readily reconverted by stirring at room temperature with 2N HCl or dilute AcOH into IIa. Refluxing I g. IIa in 25 ml. MeOH with 1 ml. PhNHNH2 gives 1.2 g. 3-(α-hydroxybenzyl)quinoxaline-2-carboxylic acid phenylhydrazide, m. 188° (decomposition) (MeOH), which (1 g.) is refluxed in 25 ml. 2N NaOH 1 hr. under N to give BzH and 400 mg. quinoxaline-2-carboxylic acid (IV), m. 215-20° (decarboxylation) (H2O). Refluxing 1 g. Ia with 1.1 g. O-C6H4(NH2)2 in 25 min. EtOH 25 min. gives 75% 2′-amino-3-(α-hydroxybenzyl)quinoxaline-2-carboxanilide (IIIa), m. 193-4° (decomposition), which is converted into 98% IIa by treating with 50 ml. 2N HCl 30 min. at room temperature Reaction of 1 g. IIIa with 10 ml. Ac2O in 10 ml. HCONMe2 (DMF) yields 81% the N-Ac derivative, m. 174-5°, which is readily hydrolyzed to IIa in 94% yield by refluxing 0.5 g. in 15 ml. EtOH and 15 ml. 2N HCl 10 min. Analogously, condensation of 2 g. 4-(p-methoxyphenyl)-2,3-dioxobutyrolactone hydrate (Ib), m. 146.8°, with 1 g. o-C6H4-(NH2)2 gives in acid medium 90% IIb, m. 165°, and in neutral EtOH 80% IIIb, m. 180° (decomposition). Dehydroascorbic acid (Ic) and 0-C6H4(NH2)2, forms in neutral solution 98% IIIc, m. 177°, which is converted in 65% yield into a yellow modification, m. 178°, by refluxing in anhydrous MeOH. Acetylation of IIIc with Ac2O in DMF gives the corresponding N-Ac derivative, m. 191° (decomposition), which yields on hydrolysis with 0.5N HCl at 5° 60%. IIc, m. 187° (decomposition). The ir spectra of the compounds are discussed. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Category: pyrazines).
Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine heterocycles and their benzo derivatives possess many interesting properties, including chemical reactivity profiles, and have diverse applications in total synthesis, medicine, chemical biology, materials, dyes, and imaging. Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.Category: pyrazines