2782-91-4Relevant academic research and scientific papers
METHOD FOR ALKYLATING A MOLECULE OR AN ION
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Page/Page column 34, (2019/04/16)
The present invention relates to a method for alkylating a molecule or an ion, wherein the molecule or the ion is alkylated by reacting it with an alkylating agent, wherein the alkylating agent is a compound according to formula (1) or a compound according to formula (4). In the formulae (1) and (4), R1 is a substituted C1-20-alkyl group, an unsubstituted C1-20-alkyl group, a substituted C3-20-cycloalkyl group or an unsubstituted C3-20-cycloaalkyl group, R2 is a substituted or unsubstituted C1-20 hydrocarbon residue or a hydrogen atom, R3 is a substituted or unsubstituted C1-20 hydrocarbon residue or a hydrogen atom, R4 and R5 are linked with each other to form an aromatic group or are independently from each other selected from the group consisting of a hydrogen atom, substituted and unsubstituted C1-20 hydrocarbon residues and electron withdrawing groups, R10 to R13 are independently from each other selected from the group consisting of a hydrogen atom, a substituted C1-20-alkyl group, an unsubstituted C1-20-alkyl group, a substituted C3-20-cycloalkyl group and an unsubstituted C3-20-cycloaalkyl group and A- is an anion.
Quantitative evaluation of the stability of gem -diaurated species in reactions with nucleophiles
Zhdanko, Alexander,Maier, Martin E.
supporting information, p. 2000 - 2006 (2013/05/08)
The reactivity of diaurated species toward nucleophiles was investigated. The reaction yields vinyl gold species and is described as simple SN2 ligand exchange at gold. Using suitably strong nucleophiles, equilibrium constants were determined to measure the stability of various diaurated species. On the basis of these equilibrium constants the influence of ligand and the nature of vinyl cores on the stability were analyzed. These results have direct implication for gold catalysis: it was demonstrated that vinyl gold intermediates bind the catalytic LAu+ species generally stronger than an alkyne (the substrate) by a factor of 106-109. This demonstrates that the formation of diaurated species from vinyl gold intermediates is thermodynamically favored in a catalytic reaction.
Dichlorothiophosphoric acid and dichlorothiophosphate anion as thionating agents in the synthesis of thioamides
Bezgubenko,Pipko,Sinitsa
experimental part, p. 1341 - 1344 (2009/02/07)
A method for the thionation of carboxylic acid amides with dichlorothiophosphoric acid and dichlorothiophosphate anion, providing thioamides in high yields, was developed. The facility of the thionation and the yields of the final products were shown to depend on the nature of the starting amide. The optimal reaction conditions are reported.
Radical cations in the OH-radical-induced oxidation of thiourea and tetramethylthiourea in aqueous solution
Wang, Wen-Feng,Schuchmann, Man Men,Schuchmann, Heinz-Peter,Knolle, Wolfgang,Von Sonntag, Justus,Von Sonntag, Clemens
, p. 238 - 245 (2007/10/03)
Hydroxyl radicals were generated radiolytically in N2O-saturated aqueous solutions of thiourea and tetramethylthiourea. The rate constant of the reaction of OH radicals with thiourea (tetramethylthiourea) has been determined using 2-propanol as well as NaN3 as competitors to be 1.2 x 1010 dm3 mol-1 s-1 (8.0 x 109 dm3 mol-1 s-1). A transient appears after a short induction period and shows a well-defined absorption spectrum with λ(max) = 400 nm (ε = 7400 dm3 mol-1 cm-1); that of tetramethylthiourea has λ(max) = 450 nm (ε = 6560 dm3 mol-1 cm-1). Using conductometric detection, it has been shown that, in both cases, OH- and a positively charged species are produced. These results indicate that a radical cation is formed. These intermediates with λ(max) = 400 nm (450 nm) are not the primary radical cations, since the intensity of the absorbance depends on the substrate concentration. The absorbance build-up follows a complex kinetics best described by the reversible formation of a dimeric radical cation by addition of a primary radical cation to a molecule of thiourea. The equilibrium constant for this addition has been determined by competition kinetics to be 5.5 x 105 dm3 mol-1 for thiourea (7.6 x 104 dm3 mol-1 for tetramethylthiourea). In the bimolecular decay of the dimeric radical cation (thiourea, 2k = 9.0 x 108 dm3 mol-1 s-1; tetramethylthiourea, 1.3 x 109 dm3 mol-1 s-1), formamidine (tetramethylformamidine) disulfide is formed. In basic solutions of thiourea, the absorbance at 400 nm of the dimeric radical cation decays rapidly, giving rise (5.9 x 107 dm3 mol-1 s-1) to a new intermediate with a broad maximum at 510 nm (ε = 750 dm3 mol-1 cm-1). This reaction is not observed in tetramethylthiourea. The absorption at 510 nm is attributed to the formation of a dimeric radical anion, via neutralization of the dimeric radical cation and subsequent deprotonation of the neutral dimeric radical. The primary radical cation of thiourea is deprotonated by OH- (2.8 x 109 dm3 mol-1 s-1) to give a neutral thiyl radical. The latter reacts rapidly with thiourea, yielding a dimeric radical, which is identical to the species from the reaction of OH- with the dimeric radical cation. The dimeric radical cations of thiourea and tetramethylthiourea are strong oxidants and readily oxidize the superoxide radical (4.5 x 109 dm3 mol-1 s-1 for thiourea and 3.8 x 109 dm3 mol-1 s-1 for tetramethylthiourea), phenolate ion (3 x 108 dm3 mol-1 s-1 for tetramethylthiourea), and even azide ion (4 x 106 dm3 mol-1 s-1 for thiourea and ~106 dm3 mol-1 s-1 for tetramethylthiourea). With O2, the dimeric radical cation of thiourea reacts relatively slowly (1.2 x 107 dm3 mol-1 s-1) and reversibly (2 x 103 s-1).
A high-yielding and facile preparation of N-substituted thioureas by substitution of nitrosothioureas with alkylamines
Xian,Zhu,Li,Cheng
, p. 1957 - 1960 (2007/10/03)
High yields of N-mono- or di- alkyl substituted thioureas are readily achieved by the reaction of nitrosothioureas with alkylamines in acetonitrile at room temperature.
Aminosilylation of heterocumulenes and the intramolecular decomposition of their silyl-functionalized adducts
Corriu, R. J. P.,Lanneau, Gerard F.,Mehta, V. D.
, p. 9 - 26 (2007/10/02)
Heteroorganic amidosilanes are readily obtained by interaction of CO2, CS2 and other heterocumulenes with pentacoordinated diaminosilanes.A comparison is made with the corresponding reactions of tetracoordinated species.Decompositon of these bifunctional organosilanes gives 2-substituted ureido derivatives and base-stabilized low coordinated silicon species, seemingly by a unimolecular thermal β-elimination.
Steric and Repeated-collision Effects in Diffusion-controlled Reactions in Solution: Kinetics of Formation of some Iodine Donor-Acceptor Complexes of Sulphur Compounds
Caldin, Edward F.,Forest, L. de,Queen, Alan
, p. 1549 - 1554 (2007/10/02)
Rates of formation of electron donor-electron acceptor complexes of iodine with some compounds of the general formula R2CS with iodine (R2CS...I-I) in 1-chlorobutane have been determined by means of a microwave temperature-jump apparatus.For each of these reactions, the observed forward rate constant (kf) is proportional to the theoretical diffusion-controlled value (k*D) over a range of temperatures, but somewhat smaller.The values of kf/k*D for the various reactions are approximately inversely proportional to the estimated surface areas of the R2CSmolecules.Assuming that the area of the reactive site is constant, this suggests that kf/k*D is proportional to the fraction of the molecule surface area that is reactive, i.e. that kf is subject to a geometrical steric factor.The obsered values of kf/k*D are, however, ca. four times larger than would be expected on this basis from molecular models, if one took into account only the frequency with which first-time collisions occur between reactant molecules with the correct orientation.This discrepancy can be removed by taking into account the fact that repeated collisions during an encounter will increase the chance of a successful collision.A hard-sphere model of encounters between molecules with limited reaction sites, reorienting by rotation between collisions, suggests that repeated collisions may contribute to kf/k*D a factor in the region of 4, in line with our experimental results.
RECYCLIZATION OF THE TRIAZOLE RING
Pudovik, A. N.,Khairullin, V. K.,Vasyanina, M. A.,Musin, R. Z.,Efremov, Yu. Ya.
, p. 175 - 176 (2007/10/02)
The reaction of 4-amino-1,2,4-triazole with N,N-dimethylchlorothioformamide in the presence of triethylamine leads to 1-dimethylaminothiocarbonyl-1,2,4-triazolio-4-amide.At 170 deg C the latter undergoes recyclization to 2-dimethylamino-1,3,4-thiadiazole.
Estimation of Charge Transfer Parameters of Complexes of Substituted Thioureas with Iodine
Seal, B. K.,Banerjee, B.,Mukherjee, D. C.
, p. 799 - 802 (2007/10/02)
A biquadratic equation in the variable b/a has been derived from Mulliken's theory of charge transfer(CT) complexes.The equation gives b/a values close to those obtained from the dipole moments of CT complexes.The solution of the equation makes use of the values of the frequency (νCT) of the CT band, the enthalpy (ΔH) of formation, obtained spectrophotometrically, for the complexes and assumed values for the overlap integral (S01).The energies of the no-bond and dative states, the resonance energies in the ground and excited states, the degree of CT in the ground state, the donor-acceptor distances in a series of complexes of thioureas with iodine and dipole moments of some of these complexes have been calculated from the values of a, b, a*, b*, S01, hνCT and ΔH with the help of the equations derived from Mulliken's theory by applying variational principle.The calculated values of the energy parameters correlate well with the strength of the complex as measured by the values of their equilibrium constants.The ionization potentials of the thioureas have also been determined.
