title: Improved synthesis, antibacterial activity and potential carcinogenicity of 5-amino-1 ,2,4-thiadiazol-3(2H)-one.
abstract: This paper reports on the preparation of 5-amino-1,2,4-thiadiazol-3(2H)-one, a sulfur-containing analogue of cytosine with the -CH=CH- group between the positions 5 and 6 of the pyrimidine ring replaced by the divalent sulfur (-S-). Improved procedures for the preparation of thiobiuret, some of its methyl derivatives and 5-amino-1,2,4-thiadiazol-3(2H)-one are documented. Thiobiuret and its N-methyl derivatives were obtained by addition of hydrogen sulfide to the respective 1-cyanoureas. Subsequent oxidation of thiobiuret with hydrogen peroxide in alkaline medium produced 5-amino-1,2,4-thiadiazol-3(2H)-one. This substance was traced back converted to the starting thiobiuret by reaction with cysteine hydrochloride. Alkaline degradation of thiadiazol led to the formation of 1-cyanourea isolated as its silver salt. An investigation of the thiadiazol biological activities has shown that it inhibits the growth of E. coil by 10% at 8.5 microM concentrations, but exhibited no cytostatic activity in L1210, HeLa S3 and HL-60 cell lines. Potential carcinogenicity of the prepared compounds was determined by a DC polarographic method. While the values of the parameter of carcinogenicity for all intermediates indicate only marginal carcinogenic potential, the value of the parameter of carcinogenicity for the thiadiazole indicates possible carcinogenicity of this compound.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: A
authors.initials: A
authors.lastname: Pískala
authors.forename: A
authors.initials: A
authors.lastname: Vachálková
authors.forename: M
authors.initials: M
authors.lastname: Masojídková
authors.forename: K
authors.initials: K
authors.lastname: Horváthová
authors.forename: Z
authors.initials: Z
authors.lastname: Ovesná
authors.forename: V
authors.initials: V
authors.lastname: Paces
authors.forename: L
authors.initials: L
authors.lastname: Novotný
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology* / Q000633:toxicity*; D001578:Benzopyrans / Q000737:chemistry*; D002273:Carcinogens / Q000138:chemical synthesis* / Q000633:toxicity*; D045744:Cell Line, Tumor; D002855:Chromatography, Thin Layer; D004659:Enbucrilate / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005663:Furans / Q000737:chemistry*; D006801:Humans; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D011048:Polarography; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013056:Spectrophotometry, Ultraviolet; D013447:Sulfites
chemical_list: D000900:Anti-Bacterial Agents; D001578:Benzopyrans; D002273:Carcinogens; D005663:Furans; D007202:Indicators and Reagents; D013447:Sulfites; C493951:furobenzopyranone; C493949:hydroxycamptothecin polybutylcyanoacrylate; D004659:Enbucrilate; C042345:hydrogen sulfite