Synthesis of 3-nitro-4-amino- and 3,4-diaminothiocoumarins

Nitration of 4-hydroxythiocoumarin gave 3-nitro-4-hydroxythiocoumarin, which was converted to 3-nitro-4-chlorothiocoumarin by the action of phosphorus oxychloride in dimethylformamide. The corresponding 3-nitro-4-aminothiocoumarins were synthesized by reaction of 3-nitro-4-chlorothiocoumarin with ammonia or amines. The 3-nitro-4-aminothiocoumarins were hydrogenated in alcohol over Raney nickel to give 3,4-diaminothiocoumarins. The-aminovinylcarbonyl form of the 4-substituted 3-aminothiocoumarins was established on the basis of the UV, IR, and PMR spectra.See [1] for our preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 43–47, January, 1978.