Quinoxaline-2-thiones preparation

Quinoxaline-thiones (144) have been prepared by heating 1,2-diamino-benzene with a-halo-ketones (RCOCH2X), sulphur, and triethylamine in dimethyl sulphoxide. ... 

Treatment of quinoxaline-2-thione (85) with methyl iodide and alkali gives 2-methylthioquinoxaline (86) and apparently no 1-methyl-quinoxaline-2-thione (87). The latter compound is prepared conven-... 

Quinoxaline-2-thione (2) is prepared from 2-chloroquinoxaline by treatment with thiourea in methanol, followed by hydrolysis of the resulting isothiouronium salt (1) with 2.5 M sodium hydroxide. A number of other quinoxaline-2-thiones have been prepared by this method, in most cases without the isolation of the intermediate isothiouronium salt. 3-Hydrazinoquinoxaline-2-thiones are obtained from the corresponding 2-chloro-3-hydrazinoquinoxalines by treatment with an aqueous solution of alkali sulfide or alkali hydrogen sulphide.3-Amino-quinoxaline-2-thione has been prepared similarly by treating 2-amino-3-chloroquinoxaline with methanolic potassium hydrogen sulfide in an... 

Various 3-substituted aminoquinoxaline-2-thiones have been prepared from quinoxaline-2,3-dithione. For example, treatment of the dithione with methylamine yields 3-methylaminoquinoxaline-2-thione, and the corresponding reaction with hydrazine hydrate yields 3-hydrazino-quinoxaline-2-thione. The latter compound is also obtained by treatment of 2,3-dichloroquinoxaline with thiourea and then with hydrazine hydrate. When 2-chloroquinoxaline 1-oxide is heated with thiourea in methanol at room temperature, an unidentified solid m.p. 184-185° is obtained alkaline hydrolysis of methanol-soluble products gives quinoxaline-2-thione in 41% yield. A method of some general applicability is illustrated by the preparation of the thioxo compound 4 from o-anilinoaniline (3). °... 

Quinoxaline-2-thione is readily converted into 2-hydrazinoqmnoxaline on treatment with hydrazine hydrate, and 3-hydrazinoquinoxaline-2-thione is readily hydrolyzed (2.5 M HCl at 70°) to quinoxaline-2,3-dione. The sodium salt of quinoxaline-2-thione has been S-alkylated with a wide range of alkyl halides to give 2-quinoxalinyl sulfides,but attempts to carry out a parallel reaction with p-nitrochlorobenzene failed. p-Nitrophenyl-2-quinoxalinyl sulfide (5) can however be prepared by reaction of 2-chloroquinoxaline with the sodium salt of p-nitro-benzenethiol. ... 

Hydrazinoquinoxalines have also been prepared by the action of hydrazine hydrate on quinoxalin-2-ones and quinoxaline-2-thiones. ... 

Hui X, Desrivot J, Bories C, Loiseau PM, Franck X, Hocquemiller R, Figadtae B (2006) Synthesis and antiprotozoal activity of some new synthetic substituted quinoxalines. Bioorg Med Chem Lett 16(4) 815-820. doi 10.1016/j.bmcl.2005.11.025 Hulme C, Tang S-Y, Bums CJ, Morize 1, Labaudiniere R (1998) Iminoved procedure for the solution phase preparation of l,4-benzodiazepine-2,5-dione libraries via Armstrong s convertible isonitrile and the Ugi reaction. J Org Chem 63(22) 8021—8023. doi 10.1021/jo980622r Humplett WJ, Lamon RW (1964a) 4-Thiazoline-2-thiones. 1. The Stmcture of intermediate... 

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