- Green Synthesis of 2-Substituted Imidazolines using Hydrogen Peroxide Catalyzed by Tungstophosphoric Acid and Tetrabutylammonium Bromide in Water
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Various 2-substituted imidazolines were constructed from aromatic aldehydes with ethylenediamine using hydrogen peroxide as an oxidant in water. Tungstophosphoric acid (HPW) was found to be active for this transformation due to its ubiquitous catalytic and oxidative nature, and further combination of tetrabutylammonium bromide (TBAB) made this transformation more efficient and attractive. It was found that the yields of the corresponding 2-substituted imidazolines were markedly influenced by the position and nature of the substituents on the phenyl ring. A plausible mechanism was also proposed to clarify this catalytic oxidative system.
- Liu, Shuai,Li, Wang,Pang, Yiying,Xiao, Hesheng,Zhou, Yi,Wang, Xiaoji
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Read Online
- Rapid and efficient synthesis of imidazolines and bisimidazolines under microwave and ultrasonic irradiation
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Small assemblies of 2-imidazolines and bisimidazolines from appropriate nitriles and ethylenediamine with catalytic amounts of P2S 5 employing a microwave assisted protocol were prepared. Sonication of this system also led to successful synthesis of 2-imidazolines and bisimidazolines. Another advantage of these systems is the ability to carry out large scale reactions. Springer-Verlag 2007.
- Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Mirkhani, Valiollah,Tangestaninejad, Shahram,Abdollahi-Alibeik, Mohammad,Yousefi, Behrooz H.,Kargar, Hadi
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- A facile and efficient synthesis of 2-imidazolines from aldehydes using hydrogen peroxide and substoichiometric sodium iodide
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The reaction of aldehydes with ethylenediamine for the preparation of 2-imidazolines has been studied using hydrogen peroxide as an oxidant in the presence of sodium iodide and anhydrous magnesium sulfate. A mild, green, and efficient method is established to carry out this reaction in high yield. Georg Thieme Verlag Stuttgart · New York.
- Bai, Guo-Yi,Xu, Kai,Chen, Guo-Feng,Yang, Yong-Hui,Li, Tian-Yu
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Read Online
- Mild and efficient one-pot synthesis of 2-imidazolines from nitriles using sodium hydrosulfide as catalyst
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A simple and efficient method has been developed for the synthesis of 2-imidazolines through a one-pot reaction of various nitriles with ethylenediamine in the presence of sodium hydrosulfide as catalyst in high yield. Copyright Taylor & Francis Group, LLC.
- Sun, Min,Wei, Hong-Tao,Li, Dong,Zheng, You-Guang,Cai, Jin,Ji, Min
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Read Online
- Efficient synthesis of 2-imidazolines in the presence of molecular iodine under ultrasound irradiation
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An efficient one-pot synthesis process for preparing 2-imidazolines from aldehydes and ethylenediamine using molecular iodine and potassium carbonate in absolute ethanol at 25-30°C under ultrasound irradiation is described. The synthetic strategy has the following advantages: mild conditions and low costs requirements, readily available catalyst, short reaction times, simplicity of operation, and good-to-excellent yields.
- Chen, Guo-Feng,Li, Hong-Yang,Xiao, Nan,Chen, Bao-Hua,Song, Ya-Li,Li, Ji-Tai,Li, Zhi-Wei
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Read Online
- A novel ternary GO@SiO2-HPW nanocomposite as an efficient heterogeneous catalyst for the synthesis of benzazoles in aqueous media
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A new solid acid catalyst, consisting of 12-phosphotungstic heteropoly acid (HPW) supported on graphene oxide/silica nanocomposite (GO@SiO2), has been developed via immobilizing HPW onto an amine-functionalized GO/SiO2 surface through coordination interaction (GO@SiO2-HPW). The GO@SiO2-HPW nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD). The prepared nanocomposite could be dispersed homogeneously in water and further used as a heterogeneous, reusable, and efficient catalyst for the synthesis of benzimidazoles and benzothiazoles by the reaction of 1,2-phenelynediamine or 2-aminothiophenol with different aldehydes.
- Habibzadeh, Setareh,Firouzzadeh Pasha, Ghasem,Tajbakhsh, Mahmood,Amiri Andi, Nasim,Alaee, Ehsan
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p. 934 - 944
(2019/06/13)
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- Cu(II) immobilized on Fe3O4@Agarose nanomagnetic catalyst functionalized with ethanolamine phosphate–salicylaldehyde schiff base: A magnetically reusable nanocatalyst for preparation of 2-substituted imidazolines, oxazolines, and thiazolines
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Herein we synthesized Cu(II) immobilized on Fe 3 O 4 @Agarose functionalized with ethanolamine phosphate–salicylaldehyde Schiff base (Fe 3 O 4 @Agarose/SAEPH 2 /Cu(II)) as a new and cost-effective nanomagnetic catalyst. The nanomagnetic catalyst was characterized by FT- IR, XRD, VSM, SEM- EDX, TEM, TGA, and ICP techniques and it was found that the particles were about 9–25 nm in size and spherical with entrapment of the Fe 3 O 4 particles in the hollow pore structure of the agarose. The prepared nanomagnetic catalyst showed excellent activity for preparation of 2-substituted imidazolines, oxazolines, and thiazolines. The catalyst is easy to prepare and exhibits higher catalytic activity than some commercially available copper sources. More importantly, this nanomagnetic catalyst can be easily recovered by using a permanent magnet and reused for at least seven cycles without significant deactivation.
- Zarei, Zeinab,Akhlaghinia, Batool
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p. 170 - 191
(2018/02/17)
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- Fe3O4@SiO2@polyionene/Br3- core-shell-shell magnetic nanoparticles: A novel catalyst for the synthesis of imidazole derivatives under solvent-free conditions
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New Fe3O4@SiO2@polyionene/Br3- core-shell-shell magnetite nanoparticles were prepared using a co-precipitation method and were used in the syntheses of imidazole derivatives under solvent-free conditions. The polyionene was easily prepared by reacting DABCO and 1,4-dibromo butane in DMF/methanol. It was then added to the previously formed layers and magnetic core-shell nanoparticles (P-MNPs) were functionalized. All the resultant nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM). The catalyst was readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.
- Dezfoolinezhad, Elham,Ghodrati, Keivan,Badri, Rashid
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p. 4575 - 4587
(2016/06/09)
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- Isoform-selective inhibitory profile of 2-imidazoline-substituted benzene sulfonamides against a panel of human carbonic anhydrases
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A series of novel benzene sulfonamides (previously evaluated as selective cyclooxygenase-2 inhibitors) has been profiled against human carbonic anhydrases I, II, IV and VII in an attempt to observe the manifestation of the well established “tail” approach
- Supuran, Claudiu T.,Kalinin, Stanislav,Tan?, Muhammet,Sarnpitak, Pakornwit,Mujumdar, Prashant,Poulsen, Sally-Ann,Krasavin, Mikhail
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p. 197 - 202
(2016/12/03)
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- Ruthenium(II) carbonyl complexes containing pyridoxal thiosemicarbazone and trans-bis(triphenylphosphine/arsine): Synthesis, structure and their recyclable catalysis of nitriles to amides and synthesis of imidazolines
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Pyridoxal N(4)-substituted thisemicarbazone hydrochloride ligands (L1-3) were synthesized and reacted with the ruthenium(II) starting complexes [RuHCl(CO)(EPh3)3] (EP or As). The resulting complexes [Ru(CO)(L1-3)(EPh3)2] (1-6) were characterized by elemental analyses and spectroscopic techniques. The molecular structure of complex 5 was identified by means of single crystal X-ray diffraction analysis. The catalytic activity of the new complexes was evaluated for the selective hydration of nitriles to primary amides and also the condensation of nitriles with ethylenediamine under solvent free conditions. The processes were operative with aromatic, heteroaromatic and aliphatic nitriles, and tolerated several substitutional groups. The studies on the effect of substitution over thiosemicarbazone, reaction time, temperature, solvent and catalyst loading were carried out in order to find the best catalyst in this series of complexes and favourable reaction conditions. A probable mechanism for both the catalytic reactions of nitrile has also been proposed. The catalyst was recovered and recycled in the hydration of nitriles for five times without any significant loss of its activity.
- Manikandan, Rajendran,Anitha, Panneerselvam,Prakash, Govindan,Vijayan, Paranthaman,Viswanathamurthi, Periasamy,Butcher, Ray Jay,Malecki, Jan Grzegorz
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p. 312 - 324
(2015/01/30)
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- Microwave-assisted cascade cycloaddition for C-N bond formation: An approach to the construction of 1,4,5,6-tetrahydropyrimidine and 2-imidazoline derivatives
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An efficient strategy for the synthesis of various 1,4,5,6- tetrahydropyrimidine and 2-imidazoline derivatives has been reported. The reactions proceeded from nitriles with ethylenediamine or 1,3-diaminopropane via cascade cycloaddition in the presence of CuL2 (L = 2-hydroxy-2-phenylacetate) to afford the corresponding 1,4,5,6- tetrahydropyrimidine or 2-imidazoline derivatives under reflux conditions or microwave irradiation in excellent yields.
- An, Shujuan,Yin, Bing,Liu, Ping,Li, Xiangnan,Li, Chen,Li, Jianli,Shi, Zhen
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p. 2525 - 2532
(2013/09/24)
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- Palladium-catalyzed multicomponent synthesis of 2-aryl-2-imidazolines from aryl halides and diamines
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An efficient palladium-catalyzed three-component reaction that combines aryl halides, isocyanides, and diamines provides access to 2-aryl-2-imidazolines in yields up to 96%. Through variation of the diamine component, the reaction can be extended to the s
- Geden, Joanna V.,Pancholi, Alpa K.,Shipman, Michael
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p. 4158 - 4164
(2013/05/22)
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- Microwave mediated solvent free synthesis of 2-arylimidazolines from aldehydes using a solid base catalyst
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2-Aryl imidazolines have been synthesized in solvent free condition using a catalytic amount of solid base (500mg) and by exposure to microwave. Ketones are not affected under these reaction conditions. Reaction time is short, clean products have been obtained and recovery is simple. The yields of the products are good.
- Das, Pranab J.,Baruah, Akashi
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experimental part
p. 752 - 755
(2012/06/30)
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- Trichloroisocyanuric acid as an efficient homogeneous catalyst for the chemoselective synthesis of 2-substituted oxazolines, imidazolines and thiazolines under solvent-free condition
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Trichloroisocyanuric acid, as a commercially available and inexpensive catalyst, was used in a new, facile and efficient procedure for the synthesis of 2-oxazolines, 2-imidazolines and 2-thiazolines through the reaction of nitriles with 2-aminoethanol, ethylenediamine or 2-aminoethanethiol under solvent-free conditions.
- Hojati, Seyedeh Fatemeh,Nezhadhoseiny, Seyede Atefe
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p. 1181 - 1189,9
(2020/09/14)
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- Copper-catalyzed synthesis of 2-imidazolines and their N-hydroxyethyl derivatives under various conditions
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A rapid and efficient method for the synthesis of 2-imidazolines and their N-hydroxyethyl derivatives from the reaction of aromatic nitriles with ethylenediamine (EDA) or N-(2-aminoethyl)ethanolamine (AEEA) using cupric indole-3-acetate (Cu(II)-(IAA)2) as a reusable catalyst under reflux and microwave conditions is reported. And seven new N-hydroxyethyl-imidazolines were reported for the first time.
- Zhang, Jin,Wang, Xiao,Yang, Meipan,Wan, Kerou,Yin, Bing,Wang, Yunxia,Li, Jianli,Shi, Zhen
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experimental part
p. 1578 - 1582
(2011/04/26)
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- Efficient and one-pot catalytic synthesis of 2-imidazolines and bis-imidazolines with p-toluenesulfonic acid under solvent free conditions
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A practical, efficient, and inexpensive method for the synthesis of 2-imidazoline from the reaction of nitriles with ethylenediamine or 1,2-propanediamine using p-toluenesulfonic acid or pyridinium p-toluenesulfonate under reflux conditions is reported. This catalyst can be successfully applied for the chemoselective conversion of dicyanobenzenes to corresponding mono- and bis-imidazolines. The applications of these catalysts are feasible because of easy preparation, easy handling, stability, inexpensive, good activity, and eco-friendly.
- Nasr-Esfahani, Masoud,Montazerozohori, Morteza,Mehrizi, Safie
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experimental part
p. 249 - 254
(2011/05/07)
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- 2-ARYL IMIDAZOLINE DERIVATIVES
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2-Aryl imidazoline derivatives are provided that are useful as anti-obesity agents or the like. A compound represented by Formula (I) or a pharmaceutically acceptable salt thereof: wherein R1 and R2 each independently represent a hydrogen atom, halogen, C1-6alkyl, or the like; R3a, R3b, R4a and R4b each independently represent a hydrogen atom, C1-6alkyl, or haloC1-6alkyl; and Ar represents aryl, wherein the aryl may be substituted with 1 to 3 substituents such as halogen, cyano, C1-6alkyl, haloC1-6alkyl, C1-6alkyloxy, haloC1-6alkyloxy, hydroxy, amino, monoC1-6alkylamino, diC1-6alkylamino, and C1-6alkyloxycarbonyl.
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Page/Page column 13
(2010/11/05)
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- Efficient catalytic synthesis of 2-imidazolines and bis-imidazolines with silica supported tungstosilicic acid
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A rapid and efficient preparation of 2-imidazolines and bis-imidazolines by the reaction of ethylenediamine or 1,2-propanediamine with nitriles in the presence of catalytic amounts of tungstosilicic acid supported on SiO 2 under reflux condition, is reported. The advantages of this procedure are moderate reaction times, good to high yields and the ability to carry out the large scale reactions. ARKAT USA, Inc.
- Nasr-Esfahani, Masoud,Montazerozohori, Morteza,Moghadam, Majid,Akhlaghia, Parisa
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experimental part
p. 97 - 109
(2010/08/04)
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- 1,3-Dibromo-5,5-dimethylhydantoin as an efficient homogeneous catalyst for the synthesis of 2-arylthiazolines and 2-arylimidazolines
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A simple, facile, and efficient procedure for the synthesis of 2-arylthizolines and 2-arylimidazolines has been developed by the simple condensation of nitriles with 2-aminoethanethiol or ethylenediamine catalyzed by 1,3-dibromo-5,5-dimethylhydantoin under solvent-free conditions. Selective preparation of bisthiozolines and monoimidazolines from dinitriles and also selective conversion of arylnitriles to their corresponding 2-arylthiazolines or imidazolines in the presence of alkylnitriles can be considered as considerable advantages of this method.
- Hojati, Seyedeh Fatemeh,Mohammadpoor-Baltork, Iraj,Maleki, Behrooz,Gholizadeh, Mostafa,Shafiezadeh, Fatemeh,Haghdoust, Mahnaz
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experimental part
p. 135 - 141
(2010/04/04)
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- Fragmentation of trifluoromethylated alkenes and acetylenes by N, N -binucleophiles. Synthesis of imidazolines or imidazolidines (Oxazolidines) controlled by substituent
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The reaction of β-halogeno-β-polyfluoromethylstyrenes with N,N- or N,O-binucleophiles leads to unexpected fragmentation products (imidazolines) or to heterocyclization giving CF3-substituted imidazolidines (N,N-) and oxazolidines (N,O-) depending on aryl substituent. The scope and the reaction mechanism are discussed.
- Nenajdenko, Valentine G.,Muzalevskiy, Vasiliy M.,Shastin, Aleksey V.,Balenkova, Elizabeth S.,Kondrashov, Evgeniy V.,Ushakov, Igor A.,Rulev, Alexander Yu.
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supporting information; scheme or table
p. 5679 - 5688
(2010/11/19)
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- Ultrasound promoted synthesis of 2-imidazolines in water: A greener approach toward monoamine oxidase inhibitors
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A series of sixteen 2-substituted-2-imidazolines (where the substituent R = Ph, Me-4-Ph; MeO-4-Ph; (MeO)2-3,4-Ph; (MeO)3-3,4,5-Ph; Ph-4-O-C(O)-Ph; Cl-4-Ph; Cl-2-Ph; Cl2-2,4-Ph; NO2-4-Ph; NO2-3-Ph; Naphth-2-yl; Fur-2-yl; Benzofur-2-yl; Pyridin-2-yl; Quinolin-2-yl) has been synthesized from the reaction of the substituted-aldehydes and ethylenediamine by ultrasound irradiation with NBS in an aqueous medium in high yields (80-99%). The 2-imidazoline ability to inhibit the activity of the A and B isoforms of monoamine oxidase (MAO) was investigated and some of them showed potent and selective MAO inhibitory activity especially for the MAO-B isoform and could become promising candidates for future development.
- Sant' Anna, Gabriela da S.,Machado, Pablo,Sauzem, Patricia D.,Rosa, Fernanda A.,Rubin, Maribel A.,Ferreira, Juliano,Bonacorso, Helio G.,Zanatta, Nilo,Martins, Marcos A.P.
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experimental part
p. 546 - 549
(2011/03/19)
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- A convenient synthesis of oxazolines and imidazolines from aromatic aldehydes with pyridinium hydrobromide perbromide in water
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Various 2-oxazolines were prepared from aromatic aldehydes and 2-aminoethanol with pyridinium hydrobromide perbromide in water at room temperature. 2-Imidazolines were also obtained in good yields from aromatic aldehydes and ethylenediamine under the same reaction conditions. Georg Thieme Verlag Stuttgart.
- Sayama, Shinsei
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p. 1479 - 1484
(2007/10/03)
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- Rapid and efficient synthesis of 2-imidazolines and bis-imidazolines under ultrasonic irradiation
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Rapid and efficient preparation of 2-imidazolines and bis-imidazolines by reaction of ethylenediamine with nitriles in the presence of catalytic amounts of sulfur under ultrasonic irradiation is reported. The advantages of this system are short reaction times, high yields and the ability to carry out large scale reactions.
- Mirkhani, Valiollah,Moghadam, Majid,Tangestaninejad, Shahram,Kargar, Hadi
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p. 2129 - 2132
(2007/10/03)
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- Microwave-assisted facile synthesis of 2-substituted 2-imidazolines
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A novel method for the synthesis of 2-substituted 2-imidazolines under microwave irradiation is reported. The yields of product obtained using this protocol are significantly high and the reaction time is reduced. ARKAT.
- Pathan, Mohsin Y.,Paike, Vijaykumar V.,Pachmase, Pandurang R.,More, Sandeep P.,Ardhapure, Suresh S.,Pawar, Rajendra P.
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p. 205 - 210
(2013/09/12)
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- A mild and efficient one-pot synthesis of 2-dihydroimidazoles from aldehydes
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The reactions of various aldehydes and 1,2-diamines followed by NXS treatment proceed at 0°C-rt to give the corresponding dihydroimidazoles in high yields. The reaction is mild, and many functional groups such as halogens, nitriles, and esters can exist.
- Fujioka, Hiromichi,Murai, Kenichi,Ohba, Yusuke,Hiramatsu, Atsushi,Kita, Yasuyuki
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p. 2197 - 2199
(2007/10/03)
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- Reactions of some ortho and para halogenated aromatic nitriles with ethylenediamine: Selective synthesis of imidazolines
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The reaction of ethylenediamine (EDA) with ortho and/or para halogenated benzonitriles did not lead to the imidazolines expected: a competitive aromatic nucleophilic substitution (SNAr) was observed instead. The selective synthesis of these imidazolines was performed by nucleophilic addition of EDA to thiobenzamide derivatives. The difference in reactivity between the nitrile and thioamide derivatives was estimated by a frontier orbital approach at the RHF/6-31G** level which predicted a greater reactivity of substituted thiobenzamides towards the nucleophilic addition of EDA.
- Crane, Louis J.,Anastassiadou, Maria,Stigliani, Jean-Luc,Baziard-Mouysset, Geneviève,Payard, Marc
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p. 5325 - 5330
(2007/10/03)
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- Zeolite-catalyzed simple synthesis of different heterocyclic rings, part 2
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A simple and environmentally friendly synthesis was developed for the preparation of 2-arylimidazoline derivatives and 2-arylbenzoxazole derivatives using a small pore size zeolite. The similar reaction was not applicable to the preparation of the sulfur-containing analogs cysteamine or 2-aminothiophenol, probably because of a disadvantageous reaction between the zeolite and the thio compound.
- Hegedues, Adrienn,Vigh, Ilona,Hell, Zoltan
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p. 428 - 431
(2007/10/03)
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- New one-step synthesis of 2-aryl-1H-imidazoles: Dehydrogenation of 2-aryl-δ2-imidazolines with dimethylsulfoxide
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A new one-step method for the preparation of 2-aryl-1Himidazoles 3, based on the DMSO dehydrogenation of 2-aryl-Δ2-imidazolines, is described. A comparative study between DMSO and 10% Pd/C, the best known catalyst employed in this transformation, has also been developed. Both protocols were carried out at 120 °C for 48 hours.
- Anastassiadou,Baziard-Mouysset,Payard
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p. 1814 - 1816
(2007/10/03)
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- On the reactivity of hydroximoyl chlorides preparation of 2-arylimidazolines
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Elimination of the hydroxylamino portion in arylhydroximoyl chlorides upon nucleophilic addition of ethylenediamine rendered an alternative procedure for 2-arylimidazolines preparation.
- Salgado-Zamora, Hector,Campos, Elena,Jimenez, Rogelio,Cervantes, Humberto
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p. 1043 - 1049
(2007/10/03)
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- Synthesis of aldehydes from carboxylic acids via 2-imidazolines
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The use of readily available 2-substituted-2-imidazolines as precursors to 2-hydroxy aldehyde, unsaturated aldehyde and a variety of functionalized aldehydes is reported. It provides a novel method for the preparation of aldehydes from carboxylic acids via 2-substituted-2-imidazolines.
- Shi, Zhen,Gu, Huan
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p. 2701 - 2707
(2007/10/03)
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- Halogenated mazindol analogs as potential inhibitors of the cocaine binding site at the dopamine transporter
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A series of halogenated (F, Cl, Br, I), pyrimido and diazepino homologs of mazindol were prepared and evaluated for their ability to displace [3H]WIN 35,428 binding and to inhibit uptake of [3H]dopamine (DA) in rat striatal tissue. All of the compounds except for the 2'-chloro (6) and 2'- bromo (16) analogs of mazindol displaced [3H]WIN 35,428 binding and inhibited [3H]DA uptake more effectively than (R)-cocaine. Structure- activity studies indicated that best inhibition of [3H]WIN 35,428 binding occurred in the imidazo series with compounds containing one or two Cl or Br atoms in the 3'- or 4'-position of the free phenyl group. Replacement of the imidazo ring by a pyrimido or diazepino ring enhanced binding inhibition. The most potent inhibitors of [3H]WIN 35,428 binding and [3H]DA uptake were 6- (3'-chlorophenyl)-2,3,4,6-tetrahydropyrimido[2,1-α]isoindol-6-ol (23; IC50 1.0 nM; 8x mazindol) and 7-(3',4'-dichlorophenyl)-2,3,4,5-tetrahydro-7H- diazepino[2,1-α]isoindol-7-ol (28; IC50 0.26 nM; 32x mazindol), respectively. No significant differences was found between binding and uptake inhibition. Mazindol and the pyrimido and diazepino homologs 24 and 27 showed a selectivity for the DA uptake over the serotonin (5-HT) uptake site of 5-, 250-, and 465-fold, respectively, and displayed weak or no affinity for a variety of neurotransmitter receptor sites.
- Houlihan, William J.,Boja, John W.,Parrino, Vincent A.,Kopajtic, Theresa A.,Kuhar, Michael J.
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p. 4935 - 4941
(2007/10/03)
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- N-Nitroso Compounds. Part 1. Structure and Decomposition of N-Nitroso-2-arylimidazolines in Aqueous Acidic Media
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Kinetic measurements for the acid-catalysed decomposition of N-nitroso-2-arylimidazolines are reported.Reactions are first-order in both +>.Two products are formed; an oxazoline, which is the product of hydrolysis of the amidine moiety, and the parent imidazoline formed by denitrosation of the substrate.These products arise from two competing pathways both of which are acid catalysed.The solvent isotope effects for the denitrosation, and amidine hydrolysis, , are 3.1 and 3.5, respectively.The denitrosation pathway, but not amidine hydrolysis, is catalysed by nucleophilic anions, and a value of 1.7 for the Swain-Scott constant, s, is obtained.In the abscence of nucleophilic anions, amidine hydrolysis is preferred over denitrosation, being twice as large as at 25 deg C.Substituents in the 2-aryl ring affect the rate of decomposition giving Hammett ρ values of 0.7 for denitrosation and 1.0 for amidine hydrolysis, which reflect the proximity of the reacting centres to the substituents.Values of the activation parameters are ΔH*NO 74 kJ/mol, ΔH*A 74 kJ/mol, ΔS*NO -48 J/K*mol and ΔS*A -43 J/K*mol.The data are interpreted in terms of a fast equilibrium protonation of the substrate, followed by competitive attack at the protonated substrate, either of water or nucleophilic anions at the nitroso nitrogen atom, or of water at the amidine carbon atom.Protonation is required to activate the substrate, the substrate being recovered from neutral or alkaline solutions unchanged.The mechanism is discussed with reference to the analogous reactions of N-nitrosoamines and N-nitrosoamides.
- Iley, Jim,Norberto, Fatima,Rosa, Eduarda
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p. 1471 - 1476
(2007/10/02)
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