Sandmeyer Diphenylurea Isatin Synthesis

Name:
Sandmeyer Diphenylurea Isatin Synthesis
Detailed information:
Formation of a cyanoformamidine by treatment of a symmetrical diphenylthiourea with potassium cyanide in alcohol containing lead carbonate, reduction with ammonium sulfide, and ring closure with concentrated sulfuric acid to isatin-2-anil; also formed smoothly by ring closure of the cyanoformamidine with aluminum chloride in benzene or carbon disulfide.