SMILES REARRANGAMENT-XV. THE S-->N TYPE REARRANGEMENT IN URACIL DERIVATIVES

Article abstract of DOI:10.1016/0040-4020(80)80097-4

The reaction of 1,3-dimethyl-6-(2-acetamidophenylthio)uracil 6 with caustic alkali followed by methylation gave 1,3-dimethyl-6-(2-methylthioanilino)uracil 7 accompanied with 1,3-dimethyl-5-acetyl-6-(2-methylthioanilino)uracil 8.Pyrimido<1,5>benzothiazepine 10 was obtained in high yield by the Smiles rearrangament of 6, trapping of the resulting thiolate ion with formalin and subsequent acid-catalysed cyclization.Treatment of 1,3-dimethyl-6-(2-aminophenylthio)uracil 5 with hot acetic acid gave 1,3-bis<(2-benzothiazolyl)acetyl>-1,3-dimethylurea 12.Upon heating 5 or N-acetyl derivative 6 in dimethylsulfoxide, 5-thiaisoalloxazine 3 was obtaiined in moderate yield.Mechanism of the observed reactions were discussed.