6-Methylquinoxaline

6-Methylquinoxaline; A solution of 3, 4-diaminotoluene (Aldrich, 100 g, 0.82 mol) in 600 mL of hot water (temp. 70-75° C.) was added rapidly to a 60° C. slurry of glyoxal-sodium bisulfite adduct (Aldrich, 239.5 g, 0.9 mol, 1.1 eq) in 400 mL of water. The resulting dark-brown clear solution was heated at 60° C. for 1 hr, then 5 g (0.02 mol) of additional glyoxal adduct was added. The mixture was allowed to cool to r.t. and filtered through a paper filter. The filtrate was neutralized with 5 M aq. NaOH to pH 7.5-7.8 and then extracted with ether (4.x.400 mL). The extract was dried over NaA generic experiment was as follows. In a two-neck roundbottomflask of 10 mL, 1, 2-phenylenediamine (1a, 0.5 mmol), 1, 2-propyleneglycol (2a, 0.6 mmol), 1.5 mL of diethylene glycol dimethylether (diglyme), and an amount of catalyst were added.Subsequently, the reaction mixture was heated at 140 °C in a siliconebath that contains a magnetic stirrer and a temperature controller.General procedure: To a mixture of substituted o-phenylenediamines derivative(2.0 mmol) and 1, 2-diketone / α-hydroxy ketone (2.0 mmol), was added sulfated polyborate (10 wtpercent). The reaction mixture was stirred at 100 °C in an oil bath. The reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was cooled to room temperature and quenched by water. The resultant product was filtered/extracted with EtOAc to get the product. Crude products were either recrystallized from ethanol or purified by column chromatography using silica as the stationary phase and EtOAc: pet. ether as mobile phase. The products obtained were known compounds and were identified by melting point and General procedure: A mixture of 1, 2-diamine (1 mmol) and α-dicarbonyl compound (1 mmol) was intimately mixed with pre-activated KF-alumina (1:4) (0.5 g) (Basic; Grade: Brockmann 1, and activated by heating under vacuum at 150 °C until bubbling ceases and then cooled to room temperature under vacuum) and stirred solid mixture with a magnetic spin bar at room temperature for hours as indicated in refPreviewPlaceHolderTable 4. After the reaction was complete, the solid mixture washed with diethyl ether (3 .x. 10 mL) and the solid was filtered off. The filtrate was concentrated and passed through a short column of silica gel to afford the quinoxalines. The desired product was pure on TLC and characterized by spectral (Preparation of: (5Z)-5-(6-quinoxalinylmethylidene)-2-[(2, 6-dichlorophenyl)amino]-1, 3-thiazol-4(5H)-one sodium salt a) 6-Methylquinoxaline. A suspension of 3, 4-diaminotoluene (50.0 g; 0.409 mol.) and glyoxal (40percent aq. soin.; 52.0 mL; 0.450 mol.) in water (150 mL) and CHA suspension of 3, 4-diaminotoluene (50.0 g; 0.409 mol.) and glyoxal (40percent aq. soln.; 52.0 mL; 0.450 mol.) in water (150 mL) and CHA suspension of 3, 4-diaminotoluene (50.0 g; 0.409 mol.) and glyoxal (40percent aq. soln.; 52.0 mlExample 8 6-Methyl-quinoxaline: A solution of 4-methyl-1, 2-phenylenediamine (5.0 g, 41 mmol) in methanol (250 mL) was treated with a solution of 40percent aqueous glyoxal and stirred for 16 h. The solvent was evaporated and the residue was distilled under vacuum (2 mm Hg, 85-88° C.) to leave a colorless oil (1.5 g, 25percent). LC/MS (Method A): r.t.=1.02 min., purity=99.5percent.General procedure: A mixture of phenylenediamine (0.9 mmol), diol or aminoalcohol (4.5 mmol), CsOH.HUnder nitrogen, [Rh (COD) Cl] 2, Zn powder, KOH and 1.0 mL of dichloromethane were added to a Schlenk tube equipped with a magnetic stir bar.A solution of ; A solution of 3, 4-diaminotoluene (Aldrich, 100 g, 0.82 mol) in 600 mL of hot water (temp. 70-75 C.) was added rapidly to a 60 C. slurry of glyoxal-sodium bisulfite adduct (Aldrich, 239.5 g, 0.9 mol, 1.1 eq) in 400 mL of water. The resulting dark-brown clear solution was heated at 60 C. for 1 hr, then 5 g (0.02 mol) of additional glyoxal adduct was added. The mixture was allowed to cool to r.t. and filtered through a paper filter. The filtrate was neutralized with 5 M aq. NaOH to pH 7.5-7.8 and then extracted with ether (4×400 mL). The extract was dried over Na2SO4 and concentrated on a rotary evaporator to afford 92 g of brown oil which was distilled in vacuum (bp. 100-102 C. at 10 mm Hg; Cavagnol, J. C.; Wiselogle, F. Y. J. Am. Chem. Soc. 1947, 69, 795; 86 C. at 1 mm Hg). Yield 89 g (75%) as a pale-yellow oil.General procedure: To a mixture of substituted o-phenylenediamines derivative(2.0 mmol) and 1, 2-diketone / alpha-hydroxy ketone (2.0 mmol), was added sulfated polyborate (10 wt%). The reaction mixture was stirred at 100 C in an oil bath. The reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was cooled to room temperature and quenched by water. The resultant product was filtered/extracted with EtOAc to get the product. Crude products were either recrystallized from ethanol or purified by column chromatography using silica as the stationary phase and EtOAc: pet. ether as mobile phase. The products obtained were known compounds and were identified by melting point and 1H and 13C NMR spectroscopy. The spectral data were compared with the literature values.General procedure: A mixture of 1, 2-diamine (1 mmol) and alpha-dicarbonyl compound (1 mmol) was intimately mixed with pre-activated KF-alumina (1:4) (0.5 g) (Basic; Grade: Brockmann 1, and activated by heating under vacuum at 150 C until bubbling ceases and then cooled to room temperature under vacuum) and stirred solid mixture with a magnetic spin bar at room temperature for hours as indicated in refPreviewPlaceHolderTable 4. After the reaction was complete, the solid mixture washed with diethyl ether (3 × 10 mL) and the solid was filtered off. The filtrate was concentrated and passed through a short column of silica gel to afford the quinoxalines. The desired product was pure on TLC and characterized by spectral (1H and 13C NMR) data and compared to those reported.Preparation of: (5Z)-5-(6-quinoxalinylmethylidene)-2-[(2, 6-dichlorophenyl)amino]-1, 3-thiazol-4(5H)-one sodium salt a) A suspension of 3, 4-diaminotoluene (50.0 g; 0.409 mol.) and glyoxal (40% aq. soln.; 52.0 mL; 0.450 mol.) in water (150 mL) and CH3CN (20.0 mL) was heated to 60 0C for 1 h. Heating was then discontinued and brine (100 mL) was added. The solution was extracted with EtOAc (3 x 150 mL) and the combined organic layers were dried over MgSO4, filtered, and concentrated in vacuo. Purification via distillation under reduced pressure (1200C, 10 torr) provided A suspension of 3, 4-diaminotoluene (50.0 g; 0.409 mol.) and glyoxal (40% aq. soln.; 52.0 ml 0.450 mol.) in water (150 mL) andCH3CN (20.0 mL) was heated to 60 0C for 1 h. Heating was then discontinued and brine (100 mL) was added. The solution was extracted with EtOAc (3 x 150 mL) and the combined organic layers were dried over MgSO4, filtered, and concentrated in vacuo. Purification via distillation under reduced pressure (120 0C, 10 torr) provided Example 8 : A solution of 4-methyl-1, 2-phenylenediamine (5.0 g, 41 mmol) in methanol (250 mL) was treated with a solution of 40% aqueous glyoxal and stirred for 16 h. The solvent was evaporated and the residue was distilled under vacuum (2 mm Hg, 85-88 C.) to leave a colorless oil (1.5 g, 25%). LC/MS (Method A): r.t.=1.02 min., purity=99.5%.General procedure: A solution of 40% aqueous glyoxal (10 mmol, 0.58 g) and sodium hydrogen sulfite (20 mmol, 2.08 g mixture of sodium bisulfate and sodium metabisulfite) in water (16 mL) was heated to 70 oC and then pured into a suspense on of 1, 2-diaminobenzene. The reaction mixture was then allowed to reach room temperature at which point it was basified to PH 7.5 with solid sodium carbonate. The organic materials were extracted with dichloromethane (3 × 20 mL) and the combined organic extracts dried and evaporated to dryness. The residue was flash chromatographed on silica gel.

Molecular Weight:144.17
XLogP3:1.7
Hydrogen Bond Acceptor Count:2
Exact Mass:144.068748264
Monoisotopic Mass:144.068748264
Topological Polar Surface Area:25.8
Heavy Atom Count:11
Complexity:136
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes