Carcinogenicity of 5 nitrofurans and related compounds with amino heterocyclic substituents

Carcinogenicity of eight 5 nitrofurans with heterocyclic substituents at the 2 position of the furan ring was investigated by feeding the chemicals to Sprague Dawley female rats. N [5 (5 nitro 2 furyl) 1,3,4 thiadiazol 2 yl]acetamide induced in 30 rats the highest incidence of tumors with the greatest number of tissues involved: forestomach squamous cell tumors (22), kidney pelvis transitional cell carcinomas (15), pulmonary alveolar cell carcinomas (16), hemangioendothelialsarcomas (20) of the intestine, mesentery, liver, lung, and pancreas, and a few tumors of other tissues. 2 Amino 5 (5 nitro 2 furyl) 1,3,4 thiadiazole, 2 amino 5 (5 nitro 2 furyl) 1,3,4 oxadiazole, and trans 2 [(dimethylamino)methylimino] 5 [2 (5 nitro 2 furyl)vinyl] 1,3,4 oxadiazole produced high incidences of mammary tumors. The other four 5 nitrofurans tested: N [4 (5 nitro 2 furyl) 2 thiazolyl]acetamide; 2,2,2 trifluoro N [4 (5 nitro 2 furyl) 2 thiazolyl]acetamide; 5 (5 nitro 2 furyl) 1,3,4 oxadiazol 2 ol; and N {[3 (5 nitro 2 furyl) 1,2,4 oxadiazol 5 yl]methyl}acetamide were associated with tumor incidences of 40 to 60%. Two other chemicals were also tested: 2 Amino 5 nitrothiazole caused a low incidence of breast and kidney pelvis tumors, and 2 amino 4 (p nitrophenyl)thiazole induced a high incidence of breast and salivary gland adenocarcinomas and lymphomas.