Hydrochloric Acid → 3-Methyl-2lambda~6~-pyrido[2,3-c][1,2,6]thiadiazine-2,2,4(1H,3H)-trione

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Reaction Steps

Methyl 2-(((methylamino)sulfonyl)amino)-3-pyridine carboxylate (11.0 grams; 0.045 mole) was dissolved in 150 ml of methanol and sodium methoxide (7.3 grams; 0.135 mole) added thereto. The resulting reaction mixture was heated at reflux temperatures for a period of about 4 hours. After cooling the reaction mixture, the solvent was removed in vacuo and the residue thus obtained suspended in 30 ml of water and the resulting suspension acidified to a pH of about 1.0 with concentrated hydrochloric acid. The reaction mixture was filtered and the precipitate thus obtained was washed with several portions of water and dried in vacuo. As a result of such operations, the desired title compound was obtained as a white powder having a melting point of 290° C.-292° C.

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