- Reaction of 2,3-dihalopropionic acids and their derivatives with P- and N-nucleophiles
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3-(Triphenylphosphoniochlorido)acrylic and 2,3-dichloropropionic acids react with triphenylphosphine to form 1,2-bis(triphenylphosphoniochlorido) ethane. Under analogous conditions, 2,3-dibromopropionic acid undergoes debromination followed by triphenylphosphine addition to give, after water treatment, 3-(triphenylphosphoniobromido)propionic acid. 2,3- Dihalopropionitriles react similarly, providing 3-(triphenylphosphoniohalido) propionitriles. The reaction of 2,3-dibromopropionamide with triphenylphosphine was performed to show that E-(triphenylphosphoniobromido)acrylic acid is capable, by contrast to what was reported previously, of reacting with triphenylphosphine. Pyridine forms with 2,3-dihalopropionic acids vinylpyridinium halides, while the reactions with aliphatic amines gives rise to dehydrohalogenation products.
- Khachikyan,Tovmasyan,Indzhikyan
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- Synthetic studies for novel structure of α-nitrogenously functionalized α-fluorocarboxylic acids. Part III. Some reactions of α-bromo-α-fluorocarboxylic acids and their ethyl esters with sodium azide
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Synthesis of a novel group of α-azido-α-fluorocarboxylic acid derivatives has been attempted by azidation of the corresponding α-bromo-α-fluorocarboxylic acids or ethyl esters.Although ethyl azidofluoroacetate was obtained, over-azidation occurred very readily in most cases to afford geminally diazidated compounds.Attemped conversion of ethyl azidofluoroacetate into azidofluoroacetic acid by alkaline hydrolysis or by treatment with trimethylsilyl bromide resulted mainly in the formation of defluorinated products.It was found that, although α-fluorocarboxylates are generally considered stable, defluorination occurs under nucleophilic conditions if an additional labilizing group is present on the same carbon atom as the fluorine.
- Takeuchi, Yoshio,Takagi, Kumiko,Yamaba, Tomokazu,Nabetani, Manabu,Koizumi, Toru
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- Conformational Stability, Barriers to Internal Rotation, Vibrational Assignment, and RHF/STO-3G* Calculations of 2-Bromopropenoyl Fluoride
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The far-infrared spectrum of gaseous 2-bromopropenoyl fluoride, CH2CBrCFO, has been recorded at a resolution of 0.10 cm-1 in the region 350-35 cm-1.The fundamental asymmetric torsional frequencies of the more stable s-trans (two double bonds oriented trans to one another) and the high-energy s-cis conformations have been observed at 61.90 and 44.27 cm-1, respectively, each with several excited states appearing at lower frequencies.From these data, the asymmetric torsional potential function governing internal rotation about the C-C bond has been determined.The potential coefficients are V1 = -17 +/- 12, V2 = 1506 +/- 48, V3 = 321 +/- 19, V4 = -43 +/- 14, and V5 = -48 +/- 7 cm-1.The s-trans-s-cis and s-cis-s-trans barriers have been determined to be 1684 +/- 35 and 1428 +/- 21 cm-1, respectively, with an energy difference between the conformations of 256 +/- 79 cm-1 (732 +/- 226 cal/mol).From studies of the Raman spectrum at variable temperatures, the conformational enthalpy difference has been determined to be 247 +/- 60 cm-1 (706 +/- 172 cal/mol) and 340 +/- 22 cm-1 (972 +/- 63 cal/mol) for the gas and liquid, respectively.A complete assignment of the vibrational fundamentals observed from the infrared spectra (3500-50 cm-1) of the gas and solid and the Raman spectra (3200-10 cm-1) of all three physical states is proposed.All of these data are compared to the corresponding quantities obtained from ab initio Hartree-Fock gradient calculations employing the STO-3G* basis set.The results are discussed and compared with the corresponding quantities obtained for some similar molecules.
- Durig, J. R.,Wang, Ai-Ying,Little, T. S.,Brletic, P. A.
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- Synthesis, thermal, mass and ab initio analyses of cyclopropane-1,1,2- tricarboxylic acid
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The preparation of cyclopropane-1,1,2-tricarboxylic acid from cyanoacetic acid and 2,3-dibropropionic acid has been done in one-step procedure in alkaline medium. The compound has been characterized, by nuclear magnetic resonance, mass spectrometry, and t
- Taoana,Holme,Bariyanga
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- Preparation of α-haloacrylate derivatives via dimethyl sulfoxide-mediated selective dehydrohalogenation
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(Chemical Equation Presented) Dimethyl sulfoxide causes α/β-dihalopropanoate derivatives to undergo efficient, selective dehydrohalogenation to form α-haloacrylate analogues. A variety of α-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of α-bromoacrolein and α-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures, this protocol is the most facile, practical, and environmentally benign process.
- Li, Wei,Li, Jianchang,Wan, Zhao-Kui,Wu, Junjun,Massefski, Walter
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p. 4607 - 4610
(2008/03/13)
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- Nematicidal alkenanilides
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A method is described for the control of nematodes in agricultural crops which comprises applying to the situs of infestation a nematicidal composition containing as active ingredient a compound of the formula STR1 wherein R1 and R2 are hydrogen, lower alkyl, or halogen, X is hydrogen or halogen, n is 1 or 2, Y is hydrogen, lower alkyl, halogen, trifluoromethyl, lower alkoxy, lower alkylthio, and nitro when n is 1, and halogen when n is 2, with the proviso that at least 1 of R1, R2, and X must be halogen. Preparation of active ingredient compounds is described, and nematicidal utility of compositions is exemplified.
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