Syntheses of 2-mono- and 2,3-disubstituted quinoxalines was written by Gowenlock, A. H.;Newbold, G. T.;Spring, F. S.. And the article was included in Journal of the Chemical Society in 1945.Name: Ethyl 3-chloroquinoxaline-2-carboxylate This article mentions the following:
For the preparation of 2,3-pyrazinedicarboxylic acids carrying certain substituents at the 5- and 5,6-positions, 2-mono- and 2,3-disubstituted quinoxalines have been synthesized. Most of these syntheses depend upon transformations of the readily available Et 2-hydroxy-3-quinoxalinecarboxylate (I). o-C6H4(NH2)2 (10.8 g.) and 17.4 g. Et ketomalonate in absolute EtOH, refluxed 1 hr., give about 18 g. of I, m. 175.5°-6.5°. Hydrolysis with 3 N NaOH on the steam bath for 30 min. gives 95% of 2-hydroxy-3-quinoxalinecarboxylic acid (II), m. 263-5° (decomposition); at 265°, II yields 72% of 2-hydroxyquinoxaline (III), sublimes at 200°/0.5 mm., m. 271°. III was also prepared in 57% yield from 2.7 g. o-C6H4(NH2)2 and 3.8 g. EtO2CCHO in EtOH (refluxing 30 min.). I (10.9 g.) and 50 cc. POCl3, heated at 110-20° for 10 min., give 90% of Et 2-chloro-3-quinoxalinecarboxylate (IV), m. 42.5° (after sublimation at 60°/6 × 10-3 mm.); it gradually turns pink in the air and is best stored as the EtOH solution at 0°. Hydrolysis of IV by refluxing with 3 N NaOH for 30 min. gives II; 2 g. of IV and 0.5 g. Na2CO3 in 50 cc. 80% MeOH, refluxed 4 hrs., give 1.8 g. of 2-chloro-3-quinoxalinecarboxylic acid (V), pale yellow, m. 146-7° (decomposition); V results also on hydrolysis of IV with aqueous MeOH-NaCN. V in anhydrous EtOH, treated at 0° with dry NH3 for 4 hrs., gives 85% of the amide, m. 214-15°; it results in small yields from IV and concentrated NH4OH in 80% MeOH at room temperature IV (4 g.) and 120 cc. EtOH-NH3 (saturated at 0°), heated 5 hrs. at 150-60°, give 77% of 2-amino-3-quinoxalinecarboxamide, bright yellow, m. 263-4°; refluxed with 10% NaOH for 3 hrs., it yields 2-amino-3-quinoxalinecarboxylic acid (VI), m. 212-13° (decomposition); with MeOH and dry HCl, this yields the HCl salt, light yellow, m. 188-9° (decomposition), of the Me ester, yellow, m. 218-19°. V and glass wool, heated at 0.1 mm. to 160°, give 2-chloroquinoxaline (VII), pale yellow, b0.5 80°, m. 46-7°; this also results in 85% yield from III and POCl3 (refluxed 20 min.) and in 18% yield by refluxing II with POCl3 for 30 min.; a HCl salt seps. from the solution in 10 N HCl. VII and EtOH-NH3, heated at 150° for 7 hrs., give. 86% of 2-aminoquinoxaline, m. 155-7°, sublimes 130-40°/10-3 mm.; it also results in 38% yield on heating VI at 250° for 3 min. IV and EtONa in EtOH, refluxed 2 hrs., give 80% of the Et ester, m. 25°, of 2-ethoxy-3-quinoxaline-carboxylic acid (VIII), m. 120-1° (70% yield on hydrolysis of the ester). VIII, heated at 180°, yields 94% of 2-ethoxyquinoxaline, m. 56-8°; it also results in 81% yield from VII and EtONa in EtOH (refluxed 1 hr.). 2,3-Dichloroquinoxaline (IX) and EtONa in EtOH, refluxed 3.5 hrs., give 80% of 2,3-diethoxyquinoxaline, m. 78°; it is not affected by boiling with 0.2 N aqueous EtOH-KOH for 1 hr. but 0.2 g. and 5 cc. HCl (d. 1.19) in 50 cc. EtOH (refluxed 1 hr.) give 2,3-dihydroxyquinoxaline; the 0.1 N NaOH solution exhibits absorption maximum at 3160, 3260, and 3410 A. (ε 12,200, 14,400, and 10,500). IX and EtOH-NH3, heated 6 hrs. at 150°, give 47% of 2,3-diaminoquinoxaline, m. 328-30° (decomposition). In the experiment, the researchers used many compounds, for example, Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0Name: Ethyl 3-chloroquinoxaline-2-carboxylate).
Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0) belongs to quinoxaline derivatives. Quinoxalines have received a significant amount of attention due to their potential use in fighting various pathophysiological conditions like epilepsy, Parkinson’s, and Alzheimer’s diseases. Quinoxalines are used as dyes, pharmaceuticals, and antibiotics such as echinomycin, levomycin exhibiting antitumoral properties. Quinoxalines establish also the basis of anthelmintics and receptor antagonists.Name: Ethyl 3-chloroquinoxaline-2-carboxylate
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider