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Journal articles on the topic 'Pentadiene-2'

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Published: 2 July 2021

Last updated: 8 February 2022

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1

Werstiuk, Nick Henry, George Timmins, Jiangong Ma, and Timothy A. Wildman. "Computational and ultraviolet photoelectron spectroscopic evidence that (Z)-2-methyl-1,3-pentadiene prefers twisted s-cis conformers in the gas phase." Canadian Journal of Chemistry 70, no. 7 (July 1, 1992): 1971–77. http://dx.doi.org/10.1139/v92-247.

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A redetermination of the ultraviolet photoelectron (pe) spectrum of (Z)-2-methyl-1,3-pentadiene has led to a correction of the published spectrum. By studying (Z)-2-methyl-1,3,-pentadiene (1a) and (E)-2-methyl-1,3-pentadiene (1b) with MMX, MNDO, AM1, and abinitio MO computational methods and pe spectroscopy, we have shown that a combination of these methods provides useful insights on the conformational behaviour of methyl-substituted 1,3-dienes in the gas phase. Synthetic pe spectra, derived from the computed potential energy surfaces and angle-dependent orbital energies, are in good agreement with experiment. Thus, the E isomer prefers the s-trans conformer but the Z isomer prefers twisted s-cis conformations in the gas phase.

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2

Haken, J. K. "New synthesis of 2-methyl-1,3-pentadiene." Journal of Applied Chemistry 14, no. 4 (May 4, 2007): 174–75. http://dx.doi.org/10.1002/jctb.5010140405.

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3

Kumar, Gaurav, Dongxia Liu, Dandan Xu, Limin Ren, Michael Tsapatsis, and Paul J. Dauenhauer. "Dehydra-decyclization of 2-methyltetrahydrofuran to pentadienes on boron-containing zeolites." Green Chemistry 22, no. 13 (2020): 4147–60. http://dx.doi.org/10.1039/d0gc00136h.

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1,3-Pentadiene (piperylene) is an important monomer in the manufacturing of adhesives, plastics, and resins. This study utilizes fundamental insights gained from the dehydra-decyclization of biomass-derived 2-methyltetrahydrofuran to achieve high piperylene yields.

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4

MISRA, NAVNIT K., DEEPTI KAPOOR, POONAM TANDON, and V. D. GUPTA. "Phonon Dispersion in 1,4-cis-Poly-(2-Methyl-1,3-Pentadiene)." Journal of Macromolecular Science, Part B 39, no. 1 (January 19, 2000): 39–51. http://dx.doi.org/10.1081/mb-100100370.

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5

Duhaime, Randy M., and Alan C. Weedon. "Direct observation of dienols produced by photochemical enolisation of α,β-unsaturated ketones: rates and activation parameters for dienol reketonisation via a 1,5-hydrogen shift." Canadian Journal of Chemistry 65, no. 8 (August 1, 1987): 1867–72. http://dx.doi.org/10.1139/v87-313.

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The production of stable solutions of Z-dienols by ultraviolet light irradiation of α,β-unsaturated ketones at low temperatures (ca. −76 °C) in d4-methanol is reported. The rates of reketonisation of the dienols via a 1,5-sigmatropic hydrogen shift were determined at various temperatures between −43 °C and + 2 °C by monitoring the proton nmr spectra of the dienols. From the data the activation parameters for the reaction were calculated. For the dienol Z-2-hydroxy-4-methyl-2,4-pentadiene, 2, derived from photoenolisation of 4-methyl-3-penten-2-one, 1, the activation energy from the Arrhenius plot is 62 ± 4 kJ/mol, and the activation entropy and enthalpy from the Eyring plot are −87 ± 15 J/mol K and 60 ± 4 kJ/mol, respectively. For the dienol Z-4-tert-butyl-2-hydroxy-2,4-pentadiene, 4, obtained from photoenolisation of 4,5,5-trimethyl-3-hexen-2-one, 3, the activation energy, entropy, and enthalpy were found to be 47 ± 5 kJ/mol, −135 ± 19 J/mol K, and 45 ± 5 kJ/mol, respectively.

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6

Arnold, Donald R., Kimberly A. McManus, and Mary S. W. Chan. "Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction, Part 13. The scope and limitations of the reaction with cyanide anion as the nucleophile." Canadian Journal of Chemistry 75, no. 8 (August 1, 1997): 1055–75. http://dx.doi.org/10.1139/v97-126.

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The scope of the photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction has been extended to include cyanide anion as the nucleophile. Highest yields of adducts were obtained when the alkene or diene has an oxidation potential less than ca. 1.5 V (SCE). No adducts were obtained from 2-methylpropene (9), oxidation potential 2.6 V. Oxidation of cyanide anion, by the radical cation of the alkene or diene, can compete with the combination. With the alkenes, 2,3-dimethyl-2-butene (2) and 2-methyl-2-butene (10), both nitriles and isonitriles were obtained; isonitriles were not detected from the reactions involving the dienes, 2-methyl-1,3-butadiene (11), 2,3-dimethyl-1,3-butadiene (12), 4-methyl-1,3-pentadiene (13), 2,4-dimethyl-1,3-pentadiene (14), and 2,5-dimethyl-2,4-hexadiene (6). The specificity, nitrile versus isonitrile, is explained in terms of the Hard-Soft-Acid-Base (HSAB) principle. The photo-NOCAS reaction also occurs with the allene, 2,4-dimethyl-2,3-pentadiene (15), cyanide combining at the central carbon. Factors influencing the regiochemistry of the combination step, Markovnikov versus anti-Markovnikov, have been defined. Cyanide anion adds preferentially to the less alkyl-substituted, less sterically hindered, end of an unsymmetric alkene or conjugated diene radical cation, forming the more heavily alkyl-substituted radical intermediate. High-level abinitio molecular orbital calculations (MP2/6-31G*//HF/6-31G*) have been used to determine the effect of alkyl substitution on the stability of the intermediates, β-cyano and β-isocyano alkyl radicals, and products, alkyl cyanides and isocyanides. The more heavily alkyl-substituted radical is not necessarily the more stable. The product ratio (Markovnikov versus anti-Markovnikov) must be kinetically controlled. Keywords: photochemistry, radical ions, electron transfer, nitriles, isonitriles.

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7

Leone, Giuseppe, Antonella Caterina Boccia, Giovanni Ricci, Antonino Giarrusso, and Lido Porri. "Polymerization of (E)-1,3-Pentadiene and (E)-2-methyl-1,3-pentadiene with neodymium catalysts: Examination of the factors that affect the stereoselectivity." Journal of Polymer Science Part A: Polymer Chemistry 51, no. 15 (April 29, 2013): 3227–32. http://dx.doi.org/10.1002/pola.26714.

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8

Arnold, Donald R., Mary S. W. Chan, and Kimberly A. McManus. "Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction, Part 12. Factors controlling the regiochemistry of the reaction with alcohol as the nucleophile." Canadian Journal of Chemistry 74, no. 11 (November 1, 1996): 2143–66. http://dx.doi.org/10.1139/v96-243.

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The photo-NOCAS reaction that combines methanol, serving as the nucleophile, and the radical cation of 4-methyl-1,3-pentadiene (14+•), substituting on the 1,4-dicyanobenzene radical anion (1−•), yields (E)-1-(4-cyanophenyl)-4-methoxy-4-methyl-2-pentene (15) as the major product. This regioisomer arises from bonding of methanol to C-4, the more heavily alkyl-substituted carbon of the diene, giving the less alkyl-substituted allylic radical. All previous examples of the photo-NOCAS reaction have yielded major adduct(s) having regiochemistry consistent with the anti-Markovnikov rule; the more heavily substituted (more stable?) β-alkoxyalkyl radical was the predominant intermediate. Empirically derived heats of formation and high-level ab initio molecular orbital calculations (MP2/6-31G*//HF/6-31G*) provide convincing evidence that of the two alternative allylic radicals, generated upon addition of methanol to 14+•, that which has the more alkyl substituted allylic radical moiety is, in fact, not the more stable. Of course, the total structure of the intermediate must be considered; the stabilizing effect of alkyl substitution on the carbon next to the oxygen of the ether moiety cannot be ignored. Ab initio molecular orbital calculations (MP2/6-31G*//HF/6-31G*) are reported for the radical cations of 2-methylpropene (2+•), 2-methyl-2-butene (6+•), 2-methyl-1,3-butadiene (9+•), 4-methyl-1,3-pentadiene (14+•), and 2,4-dimethyl-1,3-pentadiene (18+•) Calculations were also carried out on possible intermediates (bridged radical cations, distonic radical cations, and β-alkoxyalkyl radicals) involved upon reaction of these radical cations with methanol. Results of these calculations provide a basis for explaining/predicting the regiochemistry of the photo-NOCAS reaction involving methanol as the nucleophile: the major adduct(s) result(s) from attachment of methanol to that end of the alkene or diene which gives rise to the more stable intermediate radical. The more stable radical is not necessarily the more heavily alkyl substituted. Key words: photoinduced electron transfer, radicals, radical cations, ab initio molecular orbital calculations.

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9

Werstiuk, Nick Henry, and George Timmins. "A redetermination of the ultraviolet photoelectron spectrum of (Z)-2-methyl-1,3-pentadiene; evidence that twisted conformers predominate in the gas phase." Canadian Journal of Chemistry 66, no. 11 (November 1, 1988): 2954–56. http://dx.doi.org/10.1139/v88-456.

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A redetermination of the ultraviolet photoelectron spectrum of (Z)-2-methyl-1,3-pentadiene (1a) has resulted in a correction of the spectrum published by Masclet and co-workers. MMX and AM1 calculations on 1a predict that twisted s-cis conformations should be populated preferentially in the gas phase; this is in keeping with the experimentally determined -π−, π+ splitting of 1.55 ± 0.05 eV.

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10

Liu, Hsing-Jang, and Waiseng Martin Feng. "Trans-2-Diethylphosphoryloxy-1,3-Pentadiene in The Lewis acid Catalyzed Diels-Alder Reaction." Synthetic Communications 16, no. 12 (October 1986): 1485–92. http://dx.doi.org/10.1080/00397918608056399.

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11

Vitulli, Giovanni, Maurizio Giampietri, and Piero Salvadori. "Ytterbium vapour in the polymerization of 2-methylbutadiene and (E)-(Z)-1,3-pentadiene." Journal of Molecular Catalysis 65, no. 3 (April 1991): L21—L24. http://dx.doi.org/10.1016/0304-5102(91)85058-a.

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12

Kayran, Ceyhan, Saim Özkar, and Vagif M. Akhmedov. "Photo-Induced Chromiumcarbonyl Catalyzed Hydrosilylation of Conjugated Dienes with Triethylsilane: The Solvent Effect." Zeitschrift für Naturforschung B 58, no. 7 (July 1, 2003): 644–48. http://dx.doi.org/10.1515/znb-2003-0707.

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Photocatalytic hydrosilylation of conjugated dienes (1,3-butadiene, 2-methyl-1,3-butadiene, 2,3- dimethyl-1,3-butadiene, trans-1,3-pentadiene) with triethylsilane was studied by using Cr(CO)5L (L = CO, P(CH3)3, P(OCH3)3, P(C6H5)3, P(C6H11)3, NC5H5) in two very different solvents, toluene and tetrahydrofuran, for comparison with the results found in n-hexane. In toluene, the photocatalytic hydrosilylation yields the same products as those in n-hexane, with the exception of trans- 1,3-pentadiene which gives cis-1-triethylsilyl-2-pentene as the sole product. However, each of the precursor complexes shows different catalytic activities in toluene and n-hexane. The hydrosilylation of 1,3-butadiene in toluene is, in general, significantly faster than that in n-hexane. By using Cr(CO)6, Cr(CO)5[P(CH3)3] or Cr(CO)5[P(OCH3)3] in toluene, the conversion of triethylsilane increases almost linearly as the reaction proceeds, indicating the stability of the active catalyst throughout the reaction, similar to that in n-hexane. While no hydrosilylation of 1,3-butadiene could be achieved with Cr(CO)5[P(C6H5)3] or Cr(CO)5(NC5H5) in n-hexane, the same precursor complexes appear to be active in toluene, though the conversion occurs at much lower rate compared to that obtained using Cr(CO)5[P(CH3)3] or Cr(CO)5[P(OCH3)3]. The precursor complex Cr(CO)5[P(C6H11)3] shows catalytic activity neither in toluene nor in n-hexane. No photocatalytic hydrosilylation of 1,3-butadiene with triethylsilane was observed in tetrahydrofuran by using any of the precursor complexes. The relative reactivity of conjugated dienes in the hydrosilylation was investigated by using triethylsilane in the presence of Cr(CO)5[P(OCH3)3] as catalyst in toluene, and the same reactivity order was obtained as in n-hexane solution: 1,3-butadiene > 3-methyl-1,3-butadiene > 2,3-dimethyl-1,3-butadiene > trans-1,3-pentadiene. For all of the dienes, one obtains higher conversion to hydrosilylated product in toluene than in n-hexane.

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13

Xu, Zhongde, Jimmy Mays, Xuexin Chen, Nikos Hadjichristidis, F. C. Schilling, H. E. Bair, Dale S. Pearson, and Lewis J. Fetters. "Molecular characterization of poly(2-methyl-1,3-pentadiene) and its hydrogenated derivative, atactic polypropylene." Macromolecules 18, no. 12 (December 1985): 2560–66. http://dx.doi.org/10.1021/ma00154a034.

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14

Kanemasa, Shuji, Hirohiko Sakoh, Eiji Wada, and Otohiko Tsuge. "Diene-transmissive Diels-Alder Reaction Using 2-Ethoxy-3-methylene-1,4-pentadiene and 2-(2-Bromo-1-ethoxyethyl)1,3-butadiene." Bulletin of the Chemical Society of Japan 58, no. 11 (November 1985): 3312–19. http://dx.doi.org/10.1246/bcsj.58.3312.

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15

Aly, M. M. Abo, M. H. Baron, M. J. Coulange, and J. Favrot. "Assignments of the vibrational spectra of 2,5-dimethyl-2,4-hexadiene, 4-methyl-1,3-pentadiene and (E)-2-methyl-1,3-pentadiene. Effect of the terminal and lateral methyl groups." Spectrochimica Acta Part A: Molecular Spectroscopy 42, no. 4 (January 1986): 411–25. http://dx.doi.org/10.1016/0584-8539(86)80033-2.

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16

Liu, Kun, Min Sun, Fengli Xie, Cainan Hu, Zan Yang, An Li, JinKui Xia, Xu Qiu, Xu Wang, and Haoyun Deng. "1 : 1 alternating and 1 : 2 sequence-controlled radical copolymerization of 1,3-pentadiene isomers with maleic anhydride/N-phenylalkyl maleimide." Polymer Chemistry 11, no. 3 (2020): 675–81. http://dx.doi.org/10.1039/c9py01642b.

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The competition between the Diels–Alder cycloaddition and the sequence-controlled radical copolymerization of maleic anhydride/N-phenylalkyl maleimide (MAH/NPMI) with 1,3-pentadiene (PD) isomers was investigated.

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17

Liu, Lingyan, Yan Zhang, Hua Zhang, Kaimeng Huang, Bo-xin Gao, Min Zou, Xin Zhou, Hongkai Wang, and Jing Li. "The metal tin promoted cascade reaction of ketones in aqueous media for the construction of 2-bromo-4-aryl-1,3-pentadiene." Org. Biomol. Chem. 12, no. 29 (2014): 5393–99. http://dx.doi.org/10.1039/c4ob00584h.

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18

Sharipova, I. A., Kh M. Nasyrov, V. P. Mozgovaya, and A. Kh Sharipov. "ChemInform Abstract: Synthesis of 2-Methylthiophene by Catalytic Dehydrocyclization of 1,3-Pentadiene with Hydrogen Sulfide." ChemInform 31, no. 36 (June 3, 2010): no. http://dx.doi.org/10.1002/chin.200036120.

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19

Jørgensen, Tine, Helle Chris Nielsen, Nageshwar Malhotra, Jan Becher, and Mikael Begtrup. "A new diene, 2-methoxy-1,3-pentadiene-5-ol. Synthesis and intramolecular diels-alder reactions." Journal of Heterocyclic Chemistry 29, no. 7 (December 1992): 1841–45. http://dx.doi.org/10.1002/jhet.5570290727.

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20

Wang, Zhizhong, Cheng Yang, Bing Zhao, and Juzheng Liu. "An ab initio study on the conformers and vibrational frequencies of 2-methyl-1,3-pentadiene." Journal of Molecular Structure: THEOCHEM 357, no. 3 (December 1995): 283–90. http://dx.doi.org/10.1016/0166-1280(95)04291-6.

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21

Kreiter, Cornelius G., Wolfgang Conrad, and Reiner Exner. "Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, XLII [1]: Photoreaktionen von Hexacarbonyl-μ-η5:5-fulvalen-dimolybdän und -diwolfram mit konjugierten Dienen / Hindered Ligand Movements in Transition Metal Complexes, XLII [1]: Photoreactions of Hexacarbonyl-μ–η5:5-fulvalene-dimolybdenum and -ditungsten with Conjugated Dienes." Zeitschrift für Naturforschung B 48, no. 11 (November 1, 1993): 1635–50. http://dx.doi.org/10.1515/znb-1993-1124.

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Photochemical reactions of hexacarbonyl-μ-η5:5-fulvalene-dimolybdenum (1) with 1,3-butadiene (a), 2-methyl-1,3-butadiene (b), E-1,3-pentadiene (c), 2,3-dimethyl-1,3-butadiene (d), and E-3-methyl-1,3-pentadiene (e) yield the corresponding tetracarbonyl-η4-s-cisdiene-μ-η5:5-fulvalene-dimolybdenum complexes 3a-3e. In addition to 3a also η4-s-trans1,3-butadiene-tetracarbonyl-μ-η5:5-fulvalene-dimolybdenum (4) is formed. Similarily hexacarbonyl-μ-η5:5-fulvalene-ditungsten (2) forms with a and b tetracarbonyl-η4-s-cis-diene-μ-η5:5-fulvalene-ditungsten (5a, 5b) and bis(η4-s-cis-1,3-butadiene)-dicarbonyl-μ-η5:5-fulvalene-ditungsten (6). The complexes 3b —3e and also 5b are obtained as mixtures of the o- and u-isomers. Only for tetracarbonyl-η4-cis-2,3-dimethyl-1,3-butadiene-μ-η5:5-fulvalene-dimolybdenum (3d) an interconversion of the o- and u-isomers is observed with an energy barrier of ΔG183# = 73.9 kJ/mol. Both isomers of 3d show hindered inversions with energy barriers of ΔG#313 = 66.1 kJ/mol (u-3d) and ΔG183# = 36.4 kJ/mol (o-3d). For o-3d the crystal and molecular structure was determined by an X-ray diffraction analysis. Hexacarbonylµ — η5:5-bis(cyclopentadiendiyl)methane-dimolybdenum (7), hexacarbonyl-μ-η5:5-bis(cyclopentadiendiyl)ethane-dimolybdenum and hexacarbonyl-μ-η5:5-bis(cyclopentadiendiyl)propane-dimolybdenum do not react with conjugated dienes. Upon UV irradiation 7 looses CO and forms by dimerization octacarbonyl-bis(μ-η5:5-(cyclopentadiendiyl-cyclopentadien-triyl)methane)-dihydrido-tetramolybdenum (8).

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22

Collin, Guy J., and Hélène Deslauriers. "L'isomérisation de radicaux insaturés. II. Les radicaux α-éthallyles et α,γ-diméthallyles formés dans la photolyse de l'hexène-3 et du méthyl-4-pentène-2 à 147,0 et 184,9 nm." Canadian Journal of Chemistry 63, no. 4 (April 1, 1985): 944–50. http://dx.doi.org/10.1139/v85-157.

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The photolysis of cis-3-hexene and 4-methyl-cis-2-pentene has been studied at 147.0 and 184.9 nm. The fragmentation pattern of the photoexcited molecule is normal: it requires, mainly, the split of a C—C bond located in the β position relative to the double bond [Formula: see text]. Some α(C—C), β(C—H), and α(C—H) primary splits complete this mechanism. The formation of α-ethallyl and α,γ-dimethallyl radicals is important in 3-hexene and 4-methyl-2-pentene, respectively. An isomerization process, involving these two radicals, is necessary to explain the formation of part of the 1,3-pentadiene in the 3-hexene system and of all the 1,3-butadiene in the 4-methyl-2-pentene system. This process involves a 1,4-hydrogen atom transfer.

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23

Hosomi, Akira, Toshiyuki Masunari, Yoshinori Tominaga, Toshiharu Yanagi, and Makoto Hojo. "2-Trimethylsilylethyl-1,3-butadiene as a synthetic equivalent of parent cross-conjugated hexatriene, 3-methylene-1,4-pentadiene." Tetrahedron Letters 31, no. 43 (January 1990): 6201–4. http://dx.doi.org/10.1016/s0040-4039(00)97024-2.

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24

Ferro, D. R., S. Bruckner, S. V. Meille, and M. Ragazzi. "The structure of the α and β polymorphs of isotactic 1,4-cis-poly(2-methyl-1,3-pentadiene)." Macromolecules 24, no. 5 (September 1991): 1156–60. http://dx.doi.org/10.1021/ma00005a028.

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25

Wada, Eiji, Shuji Kanemasa, and Otohiko Tsuge. "Diene-Transmissive Hetero Diels–Alder Reactions of 3-Oxo-1,4-pentadiene Equivalents Leading to Functionalized 2-Chromanones." Bulletin of the Chemical Society of Japan 62, no. 4 (April 15, 1989): 1198–204. http://dx.doi.org/10.1246/bcsj.62.1198.

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26

JOERGENSEN, T., H. C. NIELSEN, N. MALHOTRA, J. BECHER, and M. BEGTRUP. "ChemInform Abstract: A New Diene, 2-Methoxy-1,3-pentadiene-5-ol. Synthesis and Intramolecular Diels-Alder Reactions." ChemInform 24, no. 20 (August 20, 2010): no. http://dx.doi.org/10.1002/chin.199320129.

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27

Kayran, Ceyhan, and Pazilaiti Rouzi. "Thermal Catalytic Hydrosilylation of Conjugated Dienes with Triethylsilane in the Presence of Tricarbonyl(o-xylene)Metal (Metal = Cr, Mo, W) Complexes." Zeitschrift für Naturforschung B 56, no. 11 (November 1, 2001): 1138–42. http://dx.doi.org/10.1515/znb-2001-1107.

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The thermal catalytic hydrosilylation of 1,3-butadiene (1), trans-2-methyl-1,3-pentadiene (2), 2,3-dimethyl-1,3-butadiene (3), and isoprene (4), with triethylsilane were studied in the presence of M(CO)3 (o-xylene) (M = Cr, Mo, W) complexes in polar and nonpolar solvents such as tetrahydrofuran, hexane and toluene. Mo(CO)3 (o-xylene) was found to be the only active catalyst for the hydrosilylation of 3 with triethylsilane, which gave 1-triethylsilyl-2,3-dimethyl- 2-butene (3a). as hydrosilylated product in tetrahydrofuran. The product was identified by means of 1H and 13C-NMR and GLC. The same catalyst, Mo(CO)3 (o-xylene), decomposed to Mo(CO)6 without giving hydrosilylated products of 1, 2 and 4 in tetrahydrofuran. M(CO)3(o-xylene) (M = Cr, Mo, W) complexes were found to be stable for about 6 h in hexane and toluene, and showed no catalytic activity for the hydrosilylation of 1, 2, 3 and 4.

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28

Yang, Tao, Lloyd Muzangwa, Dorian S. N. Parker, Ralf I. Kaiser, and Alexander M. Mebel. "Formation of 2- and 1-methyl-1,4-dihydronaphthalene isomers via the crossed beam reactions of phenyl radicals (C6H5) with isoprene (CH2C(CH3)CHCH2) and 1,3-pentadiene (CH2CHCHCHCH3)." Physical Chemistry Chemical Physics 17, no. 1 (2015): 530–40. http://dx.doi.org/10.1039/c4cp04612a.

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Crossed molecular beam reactions were exploited to elucidate the chemical dynamics of the reactions of phenyl radicals with isoprene and with 1,3-pentadiene at a collision energy of 55 ± 4 kJ mol⁻¹.

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29

Mavroudis, Anastasios, Apostolos Avgeropoulos, Nikos Hadjichristidis, Edwin L. Thomas, and David J. Lohse. "Synthesis and Morphological Behavior of Model Linear and Miktoarm Star Copolymers of 2-Methyl-1,3-Pentadiene and Styrene." Chemistry of Materials 15, no. 10 (May 2003): 1976–83. http://dx.doi.org/10.1021/cm021360j.

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30

Jung, Michael E., and Oliver Kretschik. "Enantiospecific Total Synthesis ofl-2‘,3‘-Dideoxyisonucleosides via Regioselective Opening of Optically ActiveC2-Symmetric 1,4-Pentadiene Bis-epoxide1." Journal of Organic Chemistry 63, no. 9 (May 1998): 2975–81. http://dx.doi.org/10.1021/jo9721655.

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31

Motoki, Shinichi, Takaya Sakai, Yoshihisa Matsuo, Shunichi Kametani, and Takao Saito. "Generation and Cycloaddition Reactions of 3-Styryl-1,2-thiaphosphole 2-Sulfide and 1,5-Diphenyl-2,4-pentadiene-1-thione." Bulletin of the Chemical Society of Japan 65, no. 3 (March 1992): 923–25. http://dx.doi.org/10.1246/bcsj.65.923.

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32

Kreiter, Cornelius G., Kurt Nist, and Joachim Kögler. "Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, XXXI [1]. Synthese und Dynamik von Acetyl-carbonyl-η5-cyclopentadienyl-η4-dien-wolfram-Komplexen / Hindered Ligand Movements in Transition Metal Complexes, XXXI [1]. Syntheses and Dynamics of Acetyl-carbonyl-η5-cyclopentadienyl-η4-diene-tungsten Complexes." Zeitschrift für Naturforschung B 41, no. 5 (May 1, 1986): 599–605. http://dx.doi.org/10.1515/znb-1986-0512.

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Tricarbonyl-η5-cyclopentadienyl-methyl-tungsten (1) reacts upon UV irradiation with conjugated dienes, like 1,3-butadiene (2), E-1,3-pentadiene (3), 2-methyl-1,3-butadiene (4), 2,3-dimethyl-1,3- butadiene (5), 1,3-cyclopentadiene (6) and 1,3-cyclohexadiene (7), to give the corresponding, quasisquare- pyramidal [(η5-C5H5)W(CO)(COCH3)(η4-diene)] complexes (8-13). With the unsymmetrically substituted dienes 3 and 4, only one of the possible diastereotopic complexes are obtained. At 200 to 230 K, 8-12 show two isomers, which are distinguished by the orientations (o or u) of the diene with respect to the other ligands. The interconversion of the o- and u-isomers was studied by dynamic 1H NMR spectroscopy and is explained by an intramolecular ±180° rotation of the diene ligands in the molecular plane. The barriers o f activation ⊿G* 300 are between 57.8 and 61.0 ± 1 kJ/mol.

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33

PARASUK, VUDHICHAI, and SAKULSUK UNARUNOTAI. "SOLVENT EFFECTS OF KINETICS OF [1,5] H-SHIFT IN CYCLOPENTADIENE AND ITS DERIVATIVES." Journal of Theoretical and Computational Chemistry 04, no. 01 (March 2005): 151–61. http://dx.doi.org/10.1142/s0219633605001362.

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Geometries of reactants, products (in the case of fluoro derivatives), and transition states in gas and solution phases of [1,5] H-shift of cyclopentadiene and 2-fluorocyclo-pentadiene were optimized using B3LYP/6-31++G(d,p) . The solvent effects were included using the Polarizable Continuum Model (PCM). Four solvent systems i.e. chloroform, dichloromethane, diethylether, and methanol, were considered. For cyclopentadiene, single point MP2/6-31++G(d,p) were also carried out. For cyclopentadiene and 2-fluorocyclopentadiene, using B3LYP/6-31++G(d,p) activation free energies of 25.47 and 28.74 kcal/mol respectively were yielded for the reaction in vacuum. In solutions, calculated activation energies for the reaction are slightly decreased with the reduction of around 0.5–3 kcal/mol depending on solvent. Good correlation between the solvent polarity and activation energies was also observed. Thus, the [1.5] H-shift in cyclopentadiene and its derivatives could be enhanced in polar solvents.

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34

HOSOMI, A., T. MASUNARI, Y. TOMINAGA, T. YANAGI, and M. HOJO. "ChemInform Abstract: 2-Trimethylsilylethyl-1,3-butadiene as a Synthetic Equivalent of Parent Cross-Conjugated Hexatriene, 3-Methylene-1,4-pentadiene." ChemInform 23, no. 6 (August 22, 2010): no. http://dx.doi.org/10.1002/chin.199206084.

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35

Cheng, Ming-Huei, Yuung-Hsing Ho, Chi-Chung Chen, Gene-Hsiang Lee, Shie-Ming Peng, San-Yan Chu, and Rai-Shung Liu. "Nucleophilic Addition to Tungsten .eta.4-2-(Methoxycarbonyl)-1,3-pentadiene Cations: Control of Nucleophilic Regiochemistry by the Diene Conformation." Organometallics 13, no. 10 (October 1994): 4082–91. http://dx.doi.org/10.1021/om00022a052.

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36

Wang, He, Véronique Bennevault-Celton, Bin Cheng, and Hervé Cheradame. "Cationic polymerization of 1,3-pentadiene and 2-methylpropene: Direct initiation is a general mechanism with AlCl3 in polar medium." European Polymer Journal 43, no. 3 (March 2007): 1083–90. http://dx.doi.org/10.1016/j.eurpolymj.2006.12.017.

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37

Liu, Hsing-Jang, Waiseng Martin Feng, Jeung Bea Kim, and Eric N. C. Browne. "Lewis acid catalyzed Diels–Alder reactions of two useful dienyl phosphate esters." Canadian Journal of Chemistry 72, no. 10 (October 1, 1994): 2163–75. http://dx.doi.org/10.1139/v94-275.

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The Lewis acid catalyzed Diels–Alder reactions of dienyl phosphate esters 1 and 2 were examined. 2-Diethylphosphoryloxy-1,3-butadiene (1) was found to react with a variety of α,β-unsaturated carbonyl compounds under Lewis acid catalysis with excellent regioselectivity to give synthetically useful cyclohexene derivatives. The adducts were produced in accordance with the normal rules governing the Diels–Alder addition. In the presence of stannic chloride acyclic α,β-unsaturated ketones such as ethyl vinyl ketone and methyl vinyl ketone reacted rapidly with diene phosphate 1 to give exclusively the para-addition products 8 and 9 in excellent yields. When diene 1 was treated with the complex cyclic enone ester 14 in the presence of ferric chloride the single para-rule adduct 15 was obtained in good yield. The stannic chloride catalyzed Diels–Alder reactions of trans-2-diethylphosphoryloxy-1,3-pentadiene (2) were also studied. Diene phosphate 2 reacted efficiently with a number of acyclic α,β-unsaturated ketones such as methyl vinyl ketone, ethyl vinyl ketone, and trans-3-penten-2-one with complete regio- and stereoselectivity to give single cyclohexene derivatives 38, 39, and 40.

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38

Uphade, Manoj B., Arava Amaranadha Reddy, Sopan P. Khandare, and Kavirayani R. Prasad. "Stereoselective Addition of a Lithium Anion of 1,1-Diphenyl-2-aza-pentadiene to Sulfinimines: Application to the Synthesis of (−)-Epiquinamide." Organic Letters 21, no. 22 (November 6, 2019): 9109–13. http://dx.doi.org/10.1021/acs.orglett.9b03507.

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39

MOTOKI, S., T. SAKAI, Y. MATSUO, S. KAMETANI, and T. SAITO. "ChemInform Abstract: Generation and Cycloaddition Reactions of 3-Styryl-1,2-thiaphosphole 2- Sulfide and 1,5-Diphenyl-2,4-pentadiene-1-thione." ChemInform 23, no. 28 (August 21, 2010): no. http://dx.doi.org/10.1002/chin.199228208.

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40

Mori, Yuji, Mitsutoshi Inaba, and Makoto Suzuki. "Diels-Alder reactions of (1E),(3E)-2-methyl-1-trimethylsilyloxy-1,3-pentadiene and the synthesis of multistriatins from the adducts." CHEMICAL & PHARMACEUTICAL BULLETIN 34, no. 8 (1986): 3488–91. http://dx.doi.org/10.1248/cpb.34.3488.

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41

Laohakunjit, Natta, Orapin Kerdchoechuen, Frank B. Matta, Juan L. Silva, and William E. Holmes. "Postharvest Survey of Volatile Compounds in Five Tropical Fruits Using Headspace-solid Phase Microextraction (HS-SPME)." HortScience 42, no. 2 (April 2007): 309–14. http://dx.doi.org/10.21273/hortsci.42.2.309.

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The volatiles of longon (Lansium domesticum Corr. var Dongon), mangosteen (Garcinia mangostana L. var Native), durian (Durio zibethinus L. var Monthong), rambutan (Nephelium lappaceum L. var Rong-rien), and sapodilla (Manilkara zapota van Royer var Kai) were identified by headspace-solid phase microextraction with the gas chromatography-mass spectrometry technique. The headspace volatiles of fresh, unheated, salted out with NaCl, and NaCl + heated samples were determined. Salting out gave the highest number of volatile components with the longon headspace. High temperature did not have much affect on the amount of volatiles in the headspace. Major volatiles of the total 43 volatiles in longon were 1,3,5 trioxane, (E)-2-hexenal, 3-carene, α-cubebene, isoledene, δ-selinene, and α-calacorene. Major volatiles of mangosteen were 2, 2-dimethyl-4-octanal, E-2-hexenal, benzaldehyde, (Z)-3-hexen-1-ol, hexyl–n-valerate, 1,4-pentadiene, and 2-methyl-1, 3-buten-2-ol. Volatile compounds in durian consisted of a large number of sulfur-containing compounds, which included diethyltrisulfide, diethyldisulfide, dithiolane, dimetyl sulfide, and 3-methyl-thiozolidine. Nonsulfur compounds 2-methyl butanoate, butanedioic acid, and propyl-2-ethylbutanoate were also abundant. Isocitonellol, 3-hydroxy-2-butanone, pentanal, and 4-tridecyl valerate were most abundant in ‘Rong-rien’ rambutan. A total of 23 components were characterized in sapodilla with ethyl acetate, acetaldehyde, benzyl alcohol, and 2-butenyl benzene being the major volatiles.

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42

Kumarathasan, Rajkumar, and Frans HH Leenen. "Is ATP a substrate for 15-lipoxygenase?" Biochemistry and Cell Biology 78, no. 2 (April 1, 2000): 87–91. http://dx.doi.org/10.1139/o99-073.

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Lipoxygenases catalyze peroxidation of polyunsaturated fatty acids containing the 1-cis, 4-cis pentadiene structure. Linoleic (18:2), linolenic (18:3), and arachidonic (20:4) acids are the predominant substrates for this class of enzymes. Effects of 15-lipoxygenase on the hydrolysis of adenosine 5'-triphosphate were investigated in vitro using soybean lipoxygenase and adenosine 5'-[γ-32P]triphosphate. The amount of inorganic phosphate released from adenosine 5'-triphosphate was dependent upon enzyme as well as substrate concentrations, pH, and the duration of incubation. The ATPase activity with a Vmax value of 3.3 μmol·mg protein-1·h-1 and a Km value of 5.9 mM was noted in the presence of different concentrations of ATP at pH = 7.4. Phenidone, a lipoxygenase inhibitor, had no effect on this reaction. These findings suggest that soybean lipoxygenase catalyzes the release of inorganic phosphate from ATP primarily via hydrolysis. Key words: 15-lipoxygenase, adenosine 5'-triphosphate, hydrolysis, phenidone.

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43

Hrywna, Yarek, Tamara V. Tsoi, Olga V. Maltseva, John F. Quensen, and James M. Tiedje. "Construction and Characterization of Two Recombinant Bacteria That Grow on ortho- and para-Substituted Chlorobiphenyls." Applied and Environmental Microbiology 65, no. 5 (May 1, 1999): 2163–69. http://dx.doi.org/10.1128/aem.65.5.2163-2169.1999.

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ABSTRACT Cloning and expression of the aromatic ring dehalogenation genes in biphenyl-growing, polychlorinated biphenyl (PCB)-cometabolizingComamonas testosteroni VP44 resulted in recombinant pathways allowing growth on ortho- andpara-chlorobiphenyls (CBs) as a sole carbon source. The recombinant variants were constructed by transformation of strain VP44 with plasmids carrying specific genes for dehalogenation of chlorobenzoates (CBAs). Plasmid pE43 carries the Pseudomonas aeruginosa 142 ohb genes coding for the terminal oxygenase (ISPOHB) of the ortho-halobenzoate 1,2-dioxygenase, whereas plasmid pPC3 contains the Arthrobacter globiformis KZT1 fcb genes, which catalyze the hydrolytic para-dechlorination of 4-CBA. The parental strain, VP44, grew only on low concentrations of 2- and 4-CB by using the products from the fission of the nonchlorinated ring of the CBs (pentadiene) and accumulated stoichiometric amounts of the corresponding CBAs. The recombinant strains VP44(pPC3) and VP44(pE43) grew on, and completely dechlorinated high concentrations (up to 10 mM), of 4-CBA and 4-CB and 2-CBA and 2-CB, respectively. Cell protein yield corresponded to complete oxidation of both biphenyl rings, thus confirming mineralization of the CBs. Hence, the use of CBA dehalogenase genes appears to be an effective strategy for construction of organisms that will grow on at least some congeners important for remediation of PCBs.

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44

Deslauriers, Hélène, Sylvain Dufour, and Guy J. Collin. "La photochimie de l'isoprène gazeux dans la région de l'ultraviolet très lointain." Canadian Journal of Chemistry 66, no. 6 (June 1, 1988): 1513–19. http://dx.doi.org/10.1139/v88-244.

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Yields of various products have been measured in the photolysis of isoprene at 184.9, 213.8, and 228.8 nm and at pressures between 1 and 400 Torr. At each wavelength, the major process is the rupture of a C—CH3 bond, which leads to the formation of methyl and CH2=C=CHCH2. The quantum yield for this process is 0.83 ± 0.08 at 213.8 nm. The lifetime of the intermediate involved in this process is 20 ns at 184.9 nm. Similar quantities of ethylene and C3H4[Formula: see text] and propene and acetylene [Formula: see text] are measured. All the measured yields decrease with an increase in the pressure. In addition to these fragmentation processes, isomerization reactions are also observed, particularly at 228.8 nm. They lead to the formation of 1,3- and 1,4-pentadiene as well as 3-methyl-1,2-butadiene. The Stern–Volmer plot for each isomer is different and each plot shows a strong negative curvature, indicating the complexity of the reaction process. The lifetime of each intermediate is 2 ns or less.

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45

Mavroudis, Anastasios, Apostolos Avgeropoulos, Nikos Hadjichristidis, Edwin L. Thomas, and David J. Lohse. "Synthesis and Morphological Behavior of Model 6-Miktoarm Star Copolymers, PS(P2MP)5, of Styrene (S) and 2-Methyl-1,3-Pentadiene (P2MP)." Chemistry of Materials 18, no. 8 (April 2006): 2164–68. http://dx.doi.org/10.1021/cm052477l.

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46

JUNG, M. E., and O. KRETSCHIK. "ChemInform Abstract: Enantiospecific Total Synthesis of L-2′,3′-Dideoxyisonucleosides via Regioselective Opening of Optically Active C2-Symmetric 1,4-Pentadiene Bis-epoxide." ChemInform 29, no. 35 (June 20, 2010): no. http://dx.doi.org/10.1002/chin.199835270.

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47

Elliott, Michael, Andrew W. Farnham, Norman F. Janes, Diana M. Johnson, and David A. Pulman. "Synthesis and insecticidal activity of lipophilic amides. Part 2: Effect of heteroatom replacements and of introducing methyl groups in the pentadiene system." Pesticide Science 18, no. 3 (1987): 203–9. http://dx.doi.org/10.1002/ps.2780180306.

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48

Kreiter, Cornelius G., Wolfgang Michels, and Gerhard Heeb. "Photoreaktionen von Dekacarbonyldirhenium mit Allen und unverzweigten Allenderivaten / Photoreactions of Decacarbonyldirhenium with Allene and Unbranched Derivatives of Allene." Zeitschrift für Naturforschung B 50, no. 4 (April 1, 1995): 649–60. http://dx.doi.org/10.1515/znb-1995-0430.

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Decacarbonyldirhenium (1) reacts upon UV irradiation with allene (2), 1,2-butadiene (3) and 2,3-pentadiene (4) preferentially by CO substitution and oxidative rearrangement to the corresponding enneacarbonyl-μ-η1:3-endiyl-dirhenium complexes 5, 9, and 15 and to the octacarbonyl-μ-η2:2-allene-dirhenium complexes 6, the stereoisomers 10, 11, and 16. At elevated temperature 5, 9, and 15 loose CO and yield by a reductive rearrangement also the complexes 6, 10, 11, and 16. In addition to these main products, depending upon the allene derivative used, various by-products are obtained.By-products of the reaction o f 1 with 2 are octacarbonyl-μ-η3:3-(2,3-dimethylene-buta-1,4- diyl)dirhenium (7) and μ-η2:2-allene-hexacarbonyl-μ-η1:3-1-propene-1,3-diyl-dirheniurn (8). The photo reaction of 1 with 3 yields, in addition to 9-11, tetracarbonyl-η3-(E-5-ethylidene- 4-methyl-2-cyclopenten-1-yl)rhenium (12) and tetracarbonyl-η3-(Z-5-ethyliden-4- methyl-2-cyclopenten-1-yl)rhenium (13) as a mixture of isomers. 1 and 4 form the by-products tetracarbonyl-η3-(EZ-3-penten-2-yl)rhenium (17), tetracarbonyl-η3-(EE-3-penten-2-yl)rhenium (18) and heptacarbonyl-μ-η1:2:1:2-(4,5-dimethyl-2,6-octadiene-3,6-diyl)dirhenium (19) with an unusually bridging and chelating ligand. The constitutions of the reaction products have been concluded from the IR and 1H NMR spectra. For 19 the crystal and molecular structure has been determined by X-ray diffraction analysis.

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49

Mirkovic, Jelena, Dusan Mijin, and Slobodan Petrovic. "Properties and synthesis of milrinone." Chemical Industry 67, no. 1 (2013): 17–25. http://dx.doi.org/10.2298/hemind120410057m.

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Milrinone, 1,6-dihydro-2-methyl-6-oxo-[3,4?-bipyridine]-5-carbonitrile, is a positive inotropic cardiotonic agent with vasodilator properties that acts as selective phosphodiesterase 3 inhibitor in cardiac and vascular smooth muscle. Trade names of milrinone are Primacor, Corotrop, Corotrope, and Milrila. Milrinone, an amrinone derivative, is 20 to 50 times more active than amrinone and possesses reduced propensity to side effects. The use of milrinone has created controversy in the medical as the result of increased mortality rate among patients that received high amounts of milrinone in oral form. Reaserch show that it can be benifitial for patients with severe congestive heart failure when used as short-time intravenous therapy. Milrinone properties, stability, as well as mechanism of action and synthesis under laboratory and industry conditions have been described in this paper. For industrial purposes milrinone is synthesized by condensation of cyanoacetamide with 4-(dimethylamino)-3-(4-pyridinyl)-3-buten-2-one and 4-ethoxy-3-(4-pyridinyl)-3-buten-2-one in presence of a base, or by the reaction of 1-(4-pyridinyl)- 2-propanone with ethoxymethylenmalononitrile or 4-alkoxy-3-(4-pyridinyl)-3-buten-2-one with malononitrile without the use of external base. The starting compound for these syntheses is 4-picoline. Alternative synthesis of milrinone starts from 2-methyl-3-(4-pyridylidiene)-1,1,5-tricyano-1,4-pentadiene-5-carboxamide and 2-methyl-6-oxo-1,6-dihydro-3,4?-bipyridine-5-carboxamide. Lastly, methods for milrinone synthesis in laboratory, injection preparation and purification have been summarized.

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50

Citalingam, Kamini, Faridah Abas, Nordin Lajis, Iekhsan Othman, and Rakesh Naidu. "Anti-Proliferative Effect and Induction of Apoptosis in Androgen-Independent Human Prostate Cancer Cells by 1,5-Bis(2-hydroxyphenyl)-1,4-pentadiene-3-one." Molecules 20, no. 2 (February 17, 2015): 3406–30. http://dx.doi.org/10.3390/molecules20023406.

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