6.7- Dichloro-2- methylquinoxaline

Dichloro-2-methyl-3-phenylsulfonylquinoxaline 1,4-dioxide (55, R = S02Ph) gave 2-bromo-6,7-dichloro-3-methylquinoxaline 1,4-dioxide (55, R = Br) (48% HBr, 80°C, 30 min then 20°C, 12 h 31%) 2-methyl-3-phenylsulfonylquinoxaline 1,4-dioxide gave 2-chloro-3-methylquinoxaline 1,4-dioxide (35% HCl, 70°C, 15 min 87% several analogs likewise). ... 

Bromomethyl-6,7-dichloro-3-phenylthioquinoxaline 1,4-dioxide (245, Q = SPh, R = Br) gave 6,7-dichloro-2-(2-hydroxyethylamino)-3-(2-hydroxyethy-lamino)methylquinoxaline 1,4-dioxide (245, Q = R = NHCH2CH2OH) (H2NCH2CH2OH, CHCI3, 20°C, 4 days 62% note concomitant aminolysis... 

Dichloro-2,3-dimethoxy-5-methylquinoxaline gave 5-bromomethyl-6,7-dichloro-2,3-dimethoxyquinoxaline (164) [A-bromosuccinimide (NBS), (=NCMe2CN)2 (sensitizer), MeCCl3, reflux, hv, 4h 87%].1039... 

Dichloro-2-methyl-3-methylsulfonylquinoxaline 1,4-dioxide (63) gave 6,7-dichloro-2-(3-dimethylaminopropylamino)-3-methylquinoxaline 1,4-dioxide (64) (H2NCH2CH2CH2NMe2, CHC13, dioxane, 20°C > 80°C, 10 h 47%) or N, /V -bis(6,7-dichloro-3-methyl-1,4-dioxidoquinoxaline-2-yl)hydrazine (65) (H2NNH2, EtOH, 20°C, 10 h 66%).483... 

Methylquinoxaline-2,3-dione (173) is oxidized with Co(OAc)2 Mn(OAc)2 in HBr/H20 to the 6-carboxylic acid (174),183 which on treatment with thionyl chloride is converted into 2,3-dichloro-quinoxaline-6-carbonyl chloride (175).184 The 6-sulfonyl chloride is obtained from quinoxaline-2,3-dione and chlorosulfonic acid and treatment of the resulting 6-chlorosulfonyl derivative with phosphoryl chloride and pyridine.185 Such derivatives are useful synthetic dye intermediates. 

Trichloro-7-methylquinoxaline undergoes dehydrochlorination with aqueous ethanolic potassium hydroxide to afford the 5,8-dichloro derivative, proposedly via a mechanism involving hydride ion transfer. 

Treatment of 5,6,8-trichloro-7-methylquinoxaline with alkali in aqueous ethanol gives 5,8-dichloro-7-methylquinoxaline in good yield, and... 

A range of secondary A-alkylanilines undergo oxidative olefination with 2-alkyl-quinoline, 4-methylquinoline, 1-methylisoquinoline, 2-methylquinoxaline, 2-methyl-quinazoline, 2-methylbenzo[fiG-thiazole, acetophenone, and malononitrile in DMF to form structurally diverse polysubstituted alkenes in moderate to excellent yields with excellent E Z >99 1 selectivity with the use of 2,3-dichloro-5,6-dicyano-l,4-benzoquinone as the oxidant. Mechanistically, the oxidative olefination reaction proceeds through amine oxidation followed by imine olefination." ii... 

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