598-50-5Relevant articles and documents
Oxidation of 1,3,7-trimethylxanthine by hypochlorite ion
Kheidorov,Ershov,Chalyi,Titorovich
, p. 1358 - 1362 (2011)
The kinetics of the oxidative conversion of 1,3,7-trimethylxanthine upon treatment with hypochlorite ions (OCl-) in aqueous medium at 283-298 K and pH 8.2 was studied. The reaction order with respect to each component was determined and proved to be 1. It was established that the temperature dependence of the reaction rate follows the Arrhenius equation. The activation parameters of the reaction were measured: E a = 33.58 kJ/mol, ΔH ≠ = 31.12 kJ/mol, ΔS ≠ = -170.02 J/(K mol), ΔG ≠ = 81.45 kJ/mol. The stoichiometry of the reaction was studied, and the chemistry of the oxidative conversion of caffeine treated with OCl- is discussed.
Oxyhalogen-sulfur chemistry: Bromate oxidation of 1-methyl-2-thiourea in acidic medium
Jonnalagadda, Sreekantha B.,Chinake, Cordelia R.,Simoyi, Reuben H.
, p. 13521 - 13530 (1996)
The reaction between bromate and 1-methyl-2-thiourea, CH3NH(NH2)C=S (MTU), has been studied in acidic medium. The stoichiometry of the reaction in excess MTU has been established as 4BrO3- + 3CH3NH-(NH2)C=S + 3H2O → 4Br- + 3SO42- + 3CH3NH(NH2)C=O + 6H+ (A); and in excess bromate the stoichiometry is: 8BrO3- + 5CH3NH(NH2)C=S + H2O → 4Br2 + 5SO42- + 5CH3NH(NH2)C=O + 2H+ (B). Stoichiometry B includes the oxidation of MTU (stoichiometry A) and the oxidation of Br- by the excess BrO3-: BrO3- + 5Br- + 6H+ → 3Br2 + 3H2O. In excess BrO3- the reaction is characterized by an induction period followed by formation of Br2. The reaction between Br2 and MTU is very fast with a bimolecular lower limit rate constant of 2.0 × 106 M-1 s-1 such that the formation of Br2 is an indicator for the complete consumption of MTU. The reaction could be followed by monitoring the depletion of MTU through its absorbance at λ = 239 nm or the formation of Br2 at λ = 390 nm. The rate of reaction was deduced as -d[BrO3-]/dt = k0[BrO3-][MTU][H+]2 with k0 = 14.7 ± 1.2 M-3 s-1. A proposed 17-step reaction mechanism gives good agreement between experimental data and computer simulations.
A practically simple, catalyst free and scalable synthesis of: N -substituted ureas in water
Tiwari, Lata,Kumar, Varun,Kumar, Bhuvesh,Mahajan, Dinesh
, p. 21585 - 21595 (2018/06/26)
A practically simple, mild and efficient method is developed for the synthesis of N-substituted ureas by nucleophilic addition of amines to potassium isocyanate in water without organic co-solvent. Using this methodology, a variety of N-substituted ureas (mono-, di- and cyclic-) were synthesized in good to excellent yields with high chemical purity by applying simple filtration or routine extraction procedures avoiding silica gel purification. The developed methodology was also found to be suitable for gram scale synthesis of molecules having commercial application in large volumes. The identified reaction conditions were found to promote a unique substrate selectivity from a mixture of two amines.
Activation of 1-methyl-5-nitro-2-pyrimidinone by dearomatization using a secondary amine
Asahara, Haruyasu,Yasuoka, Azusa,Nishiwaki, Nagatoshi
, p. 253 - 259 (2019/04/27)
Electron-deficient 1-methyl-5-nitro-2-pyrimidinone is easily attacked by methanol or pyrrolidine to afford the corresponding adducts, respectively, by which aromaticity of nitropyrimidinone is lost. Indeed, the amine-adduct exhibited higher reactivity than that of original structure to facilitate the reaction with 1,3-dicarbonyl compound leading to diazabicyclic compound at room temperature. The amine-adduct also underwent the ring opening reaction to furnish nitroenamines with (Z)-configuration.
