Krämer I, Schunack W
Arzneimittelforschung. 1986 Nov;36(11):1564-7.
The semicarbazides 1 and 5a-c were transformed in high yields into the biureas 3a, b and the thiobiureas 10a-c and 11a-c by addition to appropriate iso(thio)cyanates and subsequently cyclisized to the N,N'-substituted 1,3,4-oxadiazole-2,5-diamines by means of elimination of water or hydrogen sulphide. The synthesized compounds were tested for H2-antagonistic activity at the isolated spontaneously beating guinea-pig atrium, where especially 4a, b and 12c showed pronounced H2-antagonistic action.
氨基脲1和5a - c通过与适当的异（硫）氰酸酯加成，高产率地转化为缩二脲3a、b以及硫代缩二脲10a - c和11a - c，随后通过消除水或硫化氢环化生成N，N'-取代的1,3,4 - 恶二唑 - 2,5 - 二胺。在离体的自发搏动豚鼠心房上测试了合成化合物的H2拮抗活性，其中特别是4a、b和12c表现出明显的H2拮抗作用。
