1,4-Benzoxazine-2,3-dione

103 parts of isatin are introduced slowly into a solution of 190 parts of potassium peroxydisulfate in 1, 300 parts of 90% strength sulfuric acid at from 0 C. to 10 C. The mixture is then stirred for 10-20 minutes, after which it is poured onto ice. The product is filtered off and dried, giving 110 parts of 2, 3-dioxo-1, 4-benzoxazine, of melting point 285 C. (with decomposition).14.7 parts of isatin are introduced into a suspension of 29 parts of potassium peroxydisulfate in 280 parts of 30% strength sulfuric acid at room temperature. The reaction mixture is then stirred for 24 hours without cooling, after which it is poured into water. The product is filtered off and dried, giving 11 parts of 2, 3-dioxo-1, 4-benzoxazine, of melting point 279-283 C. (with decomposition).General procedure: To a solution of 2.8 g (22.0 mmol) of oxalylchloride in toluene (100 mL), 2.0 g (18.3 mmol) of 2-aminophenol were added at room temperature. After theaddition was completed, the solution was heated at reflux temperature for 2 hours, then it was left to stir atroom temperature overnight. The yellow precipitate was filtered to afford 2.6 g of Thiocarbonohydrazide, 0.106 g (1.0 mmol), was added to a solution of 0.319 g (1.0 mmol) of compound 1a in 15 mL of anhydrous 1, 4-dioxane, and the mixture was refluxed for 1-3 min until the violet color typical of 1a disappeared. The mixture was cooled and partly evaporated until a solid began to precipitate, the precipitate of 3a was filtered off, and the filtrate was further evaporated, The precipitate of 2a was filtered off. Yield 0.126 g (77%), colorless crystals, mp 273-274C(decomp., from dioxane). IR spectrum, nu, cm-1: 3136 br (NH), 1774, 1705 (C=O). 1H NMR spectrum, delta, ppm: 7.11 m (2H, Harom), 7.19 m (1H, Harom), 7.25 m (1H, Harom), 11.85 br.s (1H, NH). 13C NMR spectrum, deltaC, ppm: 115.5, 116.2, 123.0, 124.7, 125.4, 140.4 (Carom), 150.6 (C3), 153.7 (C2). Found, %: C 58.92; H 3.11; N 8.57. C8H5NO3. Calculated, %: C 58.90; H 3.09; N 8.59.General procedure: In a 100-mL round bottom flask, 0.5 g (3.06mmol) of 12a was dissolved in 30 mL of abs. ethanol at reflux temperature. Once the dissolution wascompleted, 0.42 g of INH were added and the reaction was left to stir at reflux for 3 hours (monitored by TLC).Upon cooling, a white precipitate of the title compound 8a was formed and collected by vacuum filtration. Thesame procedure was used for the synthesis of 8b, c starting from 6-chloro-

Molecular Weight:163.13
XLogP3:1
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Exact Mass:163.026943022
Monoisotopic Mass:163.026943022
Topological Polar Surface Area:55.4
Heavy Atom Count:12
Complexity:226
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes