4484-20-2Relevant articles and documents
Kinetics and mechanism of the aminolysis of cycloalkylmethyl arenesulfonates
Oh, Hyuck Keun,Song, Se Jeong,Jo, Dong-Soo,Lee, Ikchoon
, p. 91 - 96 (2007/10/03)
Nucleophilic substitution reactions of cycloalkylmethyl arenesulfonates (CmH2n-1 CH2OSO2C6H4Z) with anilines (XC6H4NH2) in methanol at 65.0 °C were studied. The reactivity order (n=4>6>7>5) reflects largely the order of steric effect of the ring size (SEs term) except for n=5, which exhibits the least reactivity. This reversal of the order for n=5 is considered to result from large rate retardation due to polar effect of the ρ*σ* term. Application of the Taft equation to the rate data for n=5 and 6 gives ρ=17·4 and 5=2·3 with correlation coefficient of 0·90. The σ* values for n=4 and 7 are estimated to be - 0·23 and - 0·11, respectively. The positive ρxz values of ca 0·3 are consistent with previous results for the reactions at primary reaction centers.
Bimolecular Nucleophilic Substitution (SN2) Reactions of Neopentyl Arenesulfonates with Anilines and Benzylamines in Methanol
Koh, Han Joong,Lee, Hai Whang,Lee, Ikchoon
, p. 253 - 258 (2007/10/02)
Bimolecular nucleophilic substitution (SN2) reactions of neopentyl arenesulfonates with anilines and benzylamines in methanol at 55.0 deg C are reported.The tightness of the transition state (TS) is similar to that for other typical SN2 processes at a primary alkyl carbon centre based on the magnitude of the cross-interaction constant ρxz (0.30) between the substituents in the nucleophile (X) and leaving group (Z).The TS variation is in accord with that predicted by the potential energy surface diagram, which in turn is consistent with the positive sign of ρxz; a later TS is obtained with a weaker nucleophile and nucleofuge.Taft's polar substituent constant, ?*, for the trimethylsilyl group is estimated to be -0.48 by using a factor of 1.875 for the fall-off of ?* from the tert-butyl to the neopentyl group and extrapolating from the experimental Taft plot.
Nucleophilic Substitution Reaction of Cumyl Arenesulfonates with Anilines
Koh, Han Joong,Lee, Hai Whang,Lee, Ikchoon
, p. 125 - 130 (2007/10/02)
The nucleophilic substitution reaction of cumyl arenesulfonate with aniline has been investigated.The reaction in acetonitrile proceeds by the SN2 mechanism with probable frontside nucleophilic attack.The large magnitude of ρXZ (=-0.75) obtained results in an observable sign reversal of ρZ at ?'X = 0.83, with a negative ρZ value for ?X > ?'X.This rather unusual phenomenon can be rationalized by a strong interaction between the nucleophile and leaving group due to their close proximity in the transition state, which in turn is a result of the frontside nucleophilic attack.The reactions in methanol indicate that the SN1 channel competes with the SN2 pathway and ion-pair return is observed when the aniline nucleophhile concentration is low.
Nucleophilic Substitution Reactions of Indan-2-yl Arenesulfonates with Anilines in Methanol
Lee, Ikchoon,Lee, Young Sook,Huh, Chul,Lee, Hai Whang,Lee, Byung Choon
, p. 2415 - 2418 (2007/10/02)
The nucleophilic substitution reactions of (Y)-indan-2-yl (Z)-arenesulfonates with (X)-anilines in methanol at 55.0 deg C are reported.Sign reversals in all three second-order cross-interaction constants, ρXY, ρYZ and ρXZ, are observed at non-interaction points Z = -0.11 (ρXY = 0), X = -0.02 (ρYZ = 0) and Y = 0.43 (ρXZ = 0) respectively, which have been ascribed to an unusually large third-order cross-interaction constant, ρXYZ = -0.53, for the reaction series.An SN2 transition state with a tilted, parallel stacked and displaced structure of the three benzene rings in the nucleophile (X), substrate (Y) and leaving group (Z) is proposed to rationalize the strong three-body coupling manifested by the large ρXYZ value.
Nucleophilic Substitution Reactions of Allyl Arenesulphonates with Anilines and N,N-Dimethylanilines
Oh, Hyuck Keun,Koh, Han Joong,Lee, Ikchoon
, p. 1981 - 1984 (2007/10/02)
Kinetic studies of the reaction of allyl arenesulphonates, I, with anilines and N,N-dimethylanilines in acetonitrile at 45.0 deg C are reported.The sign and magnitude of the cross-interaction constants ρxz (and βxz) between substituents in the nucleophile (X) and leaving group (Z) indicate that the transition state (TS) for I is relatively tight and is similar to that for the corresponding reactions of ethyl systems, rather than for benzyl systems.Variations of the simple Hammett (and Broensted) coefficients ρx (βx) and ρz (βz) with substituents Z and X, respectively, are consistent with the trend expected from a positive ρxz, i.e., that predicted by the potential energy surface diagram.The kinetic isotope effects involving N-deuteriated anilines support the mechanism proposed based on ρxz (βxz) for the reactions of I, i.e., an associative SN2 process with an earlier TS for a stronger nucleophile and/or a better leaving group.
Cross Interaction Constants As a Measure of Transition State structure. Part 7. Aminolysis of Alkyl Benzenesulphonates
Lee, Ikchoon,Choi, Young Hoon,Rhyu, Keun Woo,Shim, Chang Sub
, p. 1881 - 1886 (2007/10/02)
Kinetic studies of the reactions of methyl and ethyl benzenesulphonates with anilines and benzylamines in methanol and acetonitrile at 65.0 deg C have been reported.The magnitudes of cross-interaction constants between substituents in the nucleophile (X) and the leaving group (Z),ρxz and βxz, were found to be greater for the ethyl series which indicates a tighter transition state for ethyl rather than methyl derivatives.This unexpected trend has been rationalized by making the assumption that the small electron-donating polar effect, of the α-methyl substituent in the ethyl compounds, requires a tighter transition-state structure in addition to the major effect of steric repulsion on the activation barrier which is present in all SN2 reactions taking place at a carbon centre.
Imides: Part IV - Synthesis and Reactions of N-(Arylsulphonyloxy)cyclohex-4-ene-1,2-dicarboximides
Aly, N. F.,El-Komy, M.,Aly, N. Y.,Orabi, M. O. A.
, p. 471 - 476 (2007/10/02)
N-(Arylsulphonyloxy)cyclohex-4-ene-1,2-dicarboximides (IIa and IIb) undergo base-catalysed Lossen rearrangement with aromatic amines in refluxing ethanol to give mixtures of N-(2-arylcarbamoyl)cyclohex-4-enyl-N'-arylureas (IIIa-d) and the amine salts of arylsulphonic acids (IVa-h).Fusion of II with aromatic amines for 15 min gives mixtures of 3-arylquinazoline-2,4-diones (VIa-c) and IV; however fusion for 1 hr affords mixtures of sym-N,N'-diarylureas (VIIa-d) and IV.Compounds IIa and IIb also react with phenylhydrazine to give mixtures of VIII and phenylhydrazine saltof arylsulphonic acids (IXa and IXb).The mass spectra of IIb and IIIa are presented, and discussed.
Thermolysis of α-Azido Sulfides, Sulfoxides, and Sulfones: Dependence of Mechanism on Oxidation State of Sulfur
Jarvis, Bruce B.,Nicholas, Paul E.,Midiwo, Jacob O.
, p. 3878 - 3882 (2007/10/02)
Thermolyses of α-azidobenzyl phenyl sulfide (1), sulfoxide (3), and sulfone (2) proceed at markedly different rates.Sulfone 2 requires the highest temperature (> 150 deg C), whereas sulfide 1 loses nitrogen at 120 deg C with neighboring group participation by the sulfur atom to produce N-benzylidenebenzenesulfenamide 4 in 75percent yield.Sulfoxide 3 readily decomposes at 70 deg C through a radical-pair intermediate, which gives rise to a CIDNP effect in the reaction products.Kinetic data are presented supporting the suggested reaction mechanisms.
Synthesis of Benzoquinazoline-2,4-diones via Lossen Rearrangement of N-(Arylsulphonyloxy)naphthalene-2,3-dicarboximide Derivatives
Hamed, A. A.,El-Bieh, A. A.,Baddawy, H. A.,Metwally, R. N.
, p. 221 - 223 (2007/10/02)
Treatment of N-(arylsulphonyloxy)-1-phenylnaphthalene-2,3-dicarboximides (IIa, b) with ammonia, aromatic amines, amino acids and hydrazine hydrate brings about the imide ring opening followed by Lossen rearrangement to give benzoquinazoline-2,4-diones (IIIa-h) and the salts of arylsulphonic acids (IVa-p).
