XiRelevant articles and documents
All total 370 Articles be found
All total 370 Articles be foundSimple synthesis of fresh alkyl iodides using alcohols and hydriodic acid
Klein, Suzane M.,Zhang, Cungen,Jiang, Yu Lin
, p. 2638 - 2641 (2008)
A simple synthesis of fresh alkyl iodides using alcohols and hydriodic acid (HI) is reported. The alkyl iodides were obtained in quick and easy work-up with good to excellent yields (66-94%) and very high purities (97-99%). Freshly prepared iodomethane and 1-iodobutane were applied to synthesize biologically relevant 3,7-dimethyladenine and 9-butyladenine, which were characterized thoroughly using 1D and 2D NMR, individually.
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Kubiczek,Neugebauer
, p. 917,919 (1950)
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Organic synthesis in water/carbon dioxide emulsions
Jacobson,Lee C.T.,DaRocha,Johnston
, p. 1207 - 1210 (1999)
The synthetic reaction between a hydrophobe, benzyl chloride, and a hydrophilic nucleophile, KBr, is reported in water-in-carbon dioxide (w/c) and carbon dioxide-in-water (c/w) emulsions. Emulsions containing equal amounts of water and CO2 were
Chlorotrimethylsilane/Lithium Bromide and Hexamethyldisilane/Pyridinium Bromide Perbromide: Effective and Selective Reagents for the Conversion of Alkyl (Cycloalkyl and Aralkyl) Alcohols into Bromides
Olah, George A.,Gupta, B. G. Balaram,Malhotra, Ripudaman,Narang, Subhash C.
, p. 1638 - 1639 (1980)
Alkyl bromides were obtained in high yield in the reaction of the corresponding alcohols with chlorotrimethylsilane/lithium bromide.The reaction was equally applicable to primary, secondary, and tertiary alcohols as well as to allylic and benzylic alcohols.High regioselectivity was observed in related conversions in which hexamethyldisilane/pyridinium bromide perbromide was used.Tertiary alcohols, for example, were converted selectively into the corresponding tertiary bromides in the presence of primary and secondary hydroxylic functions.The reactions were also highly steroselective.
Simple and rapid determination of the activation parameters of organic reactions by temperature-dependent NMR spectroscopy II. Application to reversible reactions
Satoh, Masahiro,Hirota, Minoru
, p. 2619 - 2624 (1996)
A non-isothermal (NIT) method for evaluating the activation enthalpies and entropies of reactions in solutions was applied to several reversible reactions. This was realized by a stepwise elevation of the temperature of a reaction system using a variable-temperature apparatus comprising on NMR spectrometer and a quick collection of FID (free induction decay) at every plateau of the step. The rate from NIT experiments agreed well with the previously measured rates by the conventional methods.
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Harnish,Tarbell
, p. 4123,4125, 4126 (1948)
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Visible light induced 'on water' benzylic bromination with N-bromosuccinimide
Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
, p. 1097 - 1099 (2006)
Benzylic bromination of various 4-substituted toluenes (Me, tert-Bu, COOEt and COMe) was effectively conducted with NBS in pure water and with a 40 W incandescent light-bulb as an initiator of the radical chain process, while electron donating groups (OMe and NHAc) directed the reaction to electrophilic aromatic substitution.
Poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide), N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide and novel poly(N,N′-dibromo-N-phenylbenzene-1,3-disulfonamide) as powerful reagents for benzylic bromination
Ghorbani-Vaghei, Ramin,Chegini, Mohammad,Veisi, Hojat,Karimi-Tabar, Mehdi
, p. 1861 - 1865 (2009)
N,N,N′,N′-Tetrabromobenzene-1,3-disulfonamide [TBBDA], poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS], and novel poly(N,N′-dibromo-N-phenylbenzene-1,3-disulfonamide) [PBPS] can be used for bromination of benzylic positions in solvent.
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Olah,G.A.,Welch,J.
, p. 652 (1974)
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A facile conversion of thiols to alkyl halides by triphenylphosphine/N-halosuccinimides
Iranpoor,Firouzabadi,Aghapour
, p. 1176 - 1178 (2001)
Thiols are efficiently converted to alkyl halides in high to excellent yields when treated with triphenylphosphin/N-halosuccinimide (halogen: Br,Cl, and I) in dichloromethane at room temperature.
Pure branch effect on the optical properties of novel conjugated derivatives
Yang, Long,Gao, Fang,Liu, Jian,Zhong, Xiaolin,Li, Hongru,Zhang, Shengtao
, p. 582 - 583 (2010)
Pure cooperative branch effects on one- and two-photon optical properties of conjugated derivatives are presented. AMI calculations demonstrate that the electron density distribution of the frontier orbital and the dipole moment changes of the derivatives are related to the number of branches. The theoretical results show that not only the energy level of the frontier orbital could be mediated by the number of branches, but the HOMOLUMO gap could be regulated.
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Jung,M.E.,Hatfield,G.L.
, p. 4483 - 4486 (1978)
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Direct halogenation of alcohols and their derivatives with tert-Butyl halides in the ionic liquid [pmIm]Br under sonication conditions - A novel, efficient and green methodology
Ranu, Brindaban C.,Jana, Ranjan
, p. 755 - 758 (2005)
A novel halogenating reagent system for direct halogenation of alcohols has been developed. tert-Butyl bromide, chloride and iodide in combination with the ionic liquid [pmIm]Br have been found to convert alcohols into the corresponding bromides, chlorides and iodides under sonication conditions (or heating) in good yields. Although a variety of primary and secondary alcohols participated in this reaction without any difficulty, tertiary alcohols remained inert. Several alcohol derivatives such as OTMS, OTBDMS, OAc, OTS and OTHP are also transformed into the corresponding halides in one-pot fashion by this procedure. A plausible rationale for this transformation is also presented. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Tribromoisocyanuric acid/triphenylphosphine: A new system for conversion of alcohols into alkyl bromides
De Andrade, Vitor S.C.,De Mattos, Marcio C.S.
, p. 975 - 979 (2014)
An efficient and facile method has been developed for the conversion of alcohols into alkyl bromides under neutral conditions using tribromoisocyanuric acid and triphenylphosphine (molar ratio 1.0:0.7:2.0, alcohol/ tribromoisocyanuric acid/triphenylphosphine) in dichloromethane at room temperature. This method can be applied for the conversion of primary, secondary, benzylic and allylic alcohols, and their corresponding bromides are obtained in 67-82 percent yield. Tertiary alcohols do not react under these conditions.
Direct bromination of hydrocarbons catalyzed by Li2MnO 3 under oxygen and photo-irradiation conditions
Nishina, Yuta,Morita, Junya,Ohtani, Bunsho
, p. 2158 - 2162 (2013)
A method for the direct bromination of hydrocarbons with Br2 using a ubiquitous and inexpensive catalyst is highly desirable. Herein, we report the selective mono-bromination of hydrocarbons in good yield using Li2MnO3 as a catalyst under irradiation with a fluorescent room light. This new catalyst can be recycled. The effect of light was investigated using action spectra, which revealed that the reaction occurred on the surface of the catalyst.
REACTIONS IN MICROEMULSION MEDIA. NUCLEOPHILIC DISPLACEMENT REACTION OF BENZYL CHLORIDE WITH BROMIDE ION
Martin, Craig A.,McCrann, Patrick M.,Angelos, George H.,Jaeger, David A.
, p. 4651 - 4654 (1982)
A kinetic and synthetic study of the reaction of benzyl chloride with bromide ion has been performed in microemulsions composed of cetyltrimethylammonium bromide, 1-butanol, water, potassium bromide, and hexane; rates and yields of benzyl bromide formatio
SYNTHESIS OF BENZYL HALIDES FROM ALDEHYDES PROMOTED BY HALOSILANES AND 1,1,3,3-TETRAMETHYLDISILOXANE (TMDS).
Aizpurua, Jesus M.,Palomo, Claudio
, p. 1103 - 1104 (1984)
Direct synthesis of monoalkyl halides from aldehydes by a new reductive halogenation method is briefly described.
Highly Reactive Manganese(IV)-Oxo Porphyrins Showing Temperature-Dependent Reversed Electronic Effect in C-H Bond Activation Reactions
Guo, Mian,Seo, Mi Sook,Lee, Yong-Min,Fukuzumi, Shunichi,Nam, Wonwoo
, p. 12187 - 12191 (2019)
We report that Mn(IV)-oxo porphyrin complexes, MnIV(O)(TMP) (1) and MnIV(O)(TDCPP) (2), are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, via an oxygen non-rebound mechanism. Interestingly, 1 with an electron-rich porphyrin is more reactive than 2 with an electron-deficient porphyrin at a high temperature (e.g., 0 °C). However, at a low temperature (e.g., -40 °C), the reactivity of 1 and 2 is reversed, showing that 2 is more reactive than 1. To the best of our knowledge, the present study reports the first example of highly reactive Mn(IV)-oxo porphyrins and their temperature-dependent reactivity in C-H bond activation reactions.
Mild Aliphatic and Benzylic Hydrocarbon C-H Bond Chlorination Using Trichloroisocyanuric Acid
Combe, Sascha H.,Hosseini, Abolfazl,Parra, Alejandro,Schreiner, Peter R.
, p. 2407 - 2413 (2017)
We present the controlled monochlorination of aliphatic and benzylic hydrocarbons with only 1 equiv of substrate at 25-30 °C using N-hydroxyphthalimide (NHPI) as radical initiator and commercially available trichloroisocyanuric acid (TCCA) as the chlorine source. Catalytic amounts of CBr4 reduced the reaction times considerably due to the formation of chain-carrying ·CBr3 radicals. Benzylic C-H chlorination affords moderate to good yields for arenes carrying electron-withdrawing (50-85%) or weakly electron-donating groups (31-73%); cyclic aliphatic substrates provide low yields (24-38%). The products could be synthesized on a gram scale followed by simple purification via distillation. We report the first direct side-chain chlorination of 3-methylbenzoate affording methyl 3-(chloromethyl)benzoate, which is an important building block for the synthesis of vasodilator taprostene.
THE CINE O-ALKYLATION OF OXIRANYLCARBINOLS
Bird, C. W.,Hormozi, N.
, p. 705 - 706 (1988)
The reaction of the alkoxides derived from some oxyranylcarbinols with alkyl halides occurs by electrophilic attack on the oxiranyl oxygen rather than the alkoxide one leading to formation of the rearranged oxiranylcarbinyl ether.
BORON TRIFLUORIDE ETHERATE/HALIDE ION, A NOVEL REAGENT FOR THE CONVERSION OF ALLYL, BENZYL AND TERTIARY ALCOHOLS TO THE HALIDES
Mandal, Arun K.,Mahajan, S. W.
, p. 3863 - 3866 (1985)
A combination of boron trifluoride etherate and halide ion is found to be an excellent reagent for the conversion of allyl, benzyl and tertiary alcohols to the halides.
A new synthesis and application of N, N'-dibromo-N, N'-1,2-ethylene bis(2,5-dimethyl benzene sulfonamide); as a novel selective bromination agent for aromatic compounds
Ardeshir, Khazaei,Abbas, Shirdarreh
, p. 4079 - 4085 (1999)
Reaction Between Novel Compound; N, N' dibromo-N, N'-1,2- ethylene bis(2,5- dimethyl benzene sulfonamide) and aromatic compounds in the carbontetrachloride produces bromo aromatic compounds. In the case of benzene rings that contain mono activated substituted, only para - bromo isomer was formed. At the presence of benzoyl peroxide in the reaction mixture α - Hydrogen from alkyl side chain was substituted with bromine.
Free-Radical Bromination of Selected Organic Compounds in Water
Shaw, Henry,Perlmutter, Howard D.,Gu, Chen,Arco, Susan D.,Quibuyen, Titos O.
, p. 236 - 237 (1997)
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A new synthetic approach to novel spiro-β-lactams
Bhalla, Aman,Venugopalan, Paloth,Bari, Shamsher S.
, p. 4943 - 4950 (2006)
An operationally simple and efficient approach for the synthesis of novel spiro-β-lactams is described. The key reaction is a halogen-mediated intrasulfenyl cyclization of a cis-3-benzylthio-3-(prop-2-ynyloxy/-enyloxy)- β-lactam procured through a Lewis acid-mediated C-3-alkylation of the trans-3-benzylthio-3-chloro-β-lactam carbocation equivalent. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
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Koeroesi,J.
, p. 1222 - 1232 (1969)
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NHC-palladium-catalyzed ionic liquid-accelerated regioselective oxyarylation of alkynes with diaryl ethers?
Cen, Liying,He, Dan,Jiang, Huanfeng,Li, Jianxiao,Lin, Zidong,Wu, Wanqing
supporting information, p. 1983 - 1988 (2022/04/03)
The first NHC-palladium-catalyzed regioselective oxyarylation of oxime ether in a task-specific ionic liquid via C(sp3)-O and C(sp2)-O bond cleavage of two different types of ethers for the assembly of structurally diverse 4-arylisoxazoles is described. Both the basic ionic liquid [C3NH2mim]Br and NHC-Pd catalyst IPr-Pd-Im-Cl2 played an important role in this transformation. Notably, this new approach provides a practical and straightforward route to access a broad range of privileged 4-arylisoxazole structures with good yields and excellent regioselectivities. Significantly, this catalytic system can be recycled up to eight times without significant loss of catalytic activity.
[1,3]-Claisen rearrangement via removable functional group mediated radical stabilization
Alam, Md Nirshad,Dash, Soumya Ranjan,Mukherjee, Anirban,Pandole, Satish,Marelli, Udaya Kiran,Vanka, Kumar,Maity, Pradip
supporting information, p. 890 - 895 (2021/02/01)
A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermal rearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol, and a unique solvent effect are presented. The aminothiophenol was deprotected from rearrangement products as well as after derivatization to useful synthons.
