Sodium Hydroxide → HCID 23332816, compound

Participants

Reaction Steps

Diethyl N-(5methoxybenzthiazole-2-yl)-aminomethylene-malonate is, as described in Example 1A, Variant II, heated in a mixture of 10% aqueous sodium hydroxide solution and ethanol. Without isolating the 1-(2-mercapto-5-methoxyphenyl)-5-carboxypyrimidine-2,6-dione formed as intermediate, the reaction mixture is strongly acidified, 8-methoxy-1-oxo-1H-pyrimido[6,1-b]benzthiazole-4-carboxylic acid thereby precipitating out. The precipitate is subsequently stirred for about 1 hour in the acidic medium. After isolation and drying, the product has a melting point of 277°-278° C.

Provenance & Evidence