2208-89-1Relevant academic research and scientific papers
Flow-Tube Investigations of Hypergolic Reactions of a Dicyanamide Ionic Liquid Via Tunable Vacuum Ultraviolet Aerosol Mass Spectrometry
Chambreau, Steven D.,Koh, Christine J.,Popolan-Vaida, Denisia M.,Gallegos, Christopher J.,Hooper, Justin B.,Bedrov, Dmitry,Vaghjiani, Ghanshyam L.,Leone, Stephen R.
, p. 8011 - 8023 (2016/10/31)
The unusually high heats of vaporization of room-temperature ionic liquids (RTILs) complicate the utilization of thermal evaporation to study ionic liquid reactivity. Although effusion of RTILs into a reaction flow-tube or mass spectrometer is possible, competition between vaporization and thermal decomposition of the RTIL can greatly increase the complexity of the observed reaction products. In order to investigate the reaction kinetics of a hypergolic RTIL, 1-butyl-3-methylimidazolium dicyanamide (BMIM+DCA-) was aerosolized and reacted with gaseous nitric acid, and the products were monitored via tunable vacuum ultraviolet photoionization time-of-flight mass spectrometry at the Chemical Dynamics Beamline 9.0.2 at the Advanced Light Source. Reaction product formation at m/z 42, 43, 44, 67, 85, 126, and higher masses was observed as a function of HNO3 exposure. The identities of the product species were assigned to the masses on the basis of their ionization energies. The observed exposure profile of the m/z 67 signal suggests that the excess gaseous HNO3 initiates rapid reactions near the surface of the RTIL aerosol. Nonreactive molecular dynamics simulations support this observation, suggesting that diffusion within the particle may be a limiting step. The mechanism is consistent with previous reports that nitric acid forms protonated dicyanamide species in the first step of the reaction.
Improved synthesis, antibacterial activity and potential carcinogenicity of 5-amino-1,2,4-thiadiazol-3(2H)-one
Piskala,Vachalkova,Masojidkova,Horvathova,Ovesna,Paces,Novotny, Ladislav
, p. 756 - 762 (2007/10/03)
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. coli by 10% at 8.5 μM 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.
ACID-CATALYSED HYDROLYSIS OF CYANAMIDES: ESTIMATES OF CARBODI-IMIDE BASICITY AND TAUTOMERIC EQUILIBRIUM CONSTANT BETWEEN CARBODI-IMIDE AND CYANAMIDE
Hill, Stephen V.,Williams, Andrew,Longridge, Jethro L.
, p. 1009 - 1014 (2007/10/02)
N-cyanourea is demonstrated as an intermediate in the hydrolysis of dicyanamide which is shown to react as its carbodi-imide tautomer.The hydrolysis of N-cyanourea, dicyanamide, and NN'-dimethylcyanoguanidine is specific acid-catalysed.Generaln acid catalysis is demonstrated for ht e hydrolysis of NN'-dimethylcyanoguanidine and is considered to be specific acid-nucleophilic.Assuming the carbodi-imide mechanism also holds for hte specific acid catalysed hydrolysis of cyanamide the tautomeric equilibrium constant for formation of ht eparent carbodi-imide in water at 25 deg C is estimated to be have a value within one unit of zero.Rate constant are reported for alkaline hydrolysis of cyanamides.
