- P-Triazinylphosphonium chlorides as a new group of coupling reagents
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Tertiary phosphines in reaction with 2-chloro-4,6-dialkoxy-1,3,5-triazines gave unstable quaternary P-triazinylphosphonium chlorides, which readily decomposed with a departure of the alkyl group of the triazine ring substituent. Stable quaternary P-triazinylphosphonium chlorides were obtained only in reaction of 2-chloro-4,6-diphenoxy-1,3,5-triazine. Both, stable quaternary P-triazinylphosphonium chlorides as well unstable analogues prepared in situ activated carboxylic acid yielding "superactive" triazine esters, useful as highly efficient reagents in peptide bond synthesis.
- Kolesinska, Beata,Mrozek, Agnieszka,Fraczyk, Justyna,Kaminski, Zbigniew J.
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p. 569 - 583
(2013/08/24)
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- Trifluoromethylthiolation of 1,3-dithiane
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With a view to synthesize 2-(trifluoromethylthio)-1,3-dithiane (1), 1,3-dithiane (2) was reacted in dry pentane at -78°C under dry N2 with trifluoromethylsulfenyl chloride (3) and was found to furnish the desired compound in poor yields along with ten other compounds. Under similar conditions, 2-lithio-1,3-dithiane on treatment with 2 and bis-(trifluoromethyl) disulfide (4) gave 8.0% and 10.0% yields of 1, respectively. In connection with this study, (cholromethyl) propyl sulfide and bis(propylthio)methane were synthesized. The reaction of the latter with 3 was also investigated. The characterization of the primary compound formed in the reaction of 2 with 3 using the 'INAPT'-NMR and GC-MS, the probable mechanism of the formation of the various compounds and their mass spectral identification are presented in this article. Copyright Taylor & Francis Group, LLC.
- Munavalli,Rohrbaugh,Szafraniec,Durst
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p. 305 - 324
(2008/02/04)
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- Synthesis and Photochromism of Crowned Spirobenzothiapyran: Facilitated Photoisomerization by Cooperative Complexation of Crown Ether and Thiophenolate Moieties with Metal Ions
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Spirobenzothiapyrans bearing monoaza-12-crown-4, -15-crown-5, -18-crown-6, and oligooxyethylene moieties were synthesized, and their photochromism was examined in the presence of cations in acetonitrile. The cation complexation by their crown ether moieties cannot induce thermal isomerization to their corresponding colored merocyanine form, unlike the corresponding spirobenzopyran derivatives. The UV-light-induced isomerization was, however, facilitated by the cation complexation of the crown ether moieties and the affinity of the merocyanine thiophenolate anion to metal ions, especially in the presence of Li+ and Ag+. The presence of Ag+ brought about the most remarkable effect in the facilitation of photoisomerization of the spirobenzothiapyrans and the thermal stability of the colored merocyanine form mainly due to the powerful interaction of the thiophenolate anion with the soft metal ion.
- Tanaka, Mutsuo,Kamada, Kenji,Ando, Hisanori,Kitagaki, Takashi,Shibutani, Yasuhiko,Kimura, Keiichi
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p. 4342 - 4347
(2007/10/03)
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- Synthesis of 6,6'-diamino-2,2'-biquinoline and 2,2'-bi-1,6- naphthyridine
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High-yield synthesis and characterization of the new heterocycles 6,6'- diamino-2,2'-biquinoline (3), 6,6'-bis(N,N-dimethyl-amino)-2,2'-biquinoline (4), and 2,2'-bi-1,6-naphthyridine (5) are described. The preparation of 3 and 4 is based on the coupling of 2-amino-6-chloroquinoline and 2-chloro-6- dimethylaminoquinoline in the presence of NiCl2·6H2O/PPh3/Zn in DMF (NiCRA). Compound 5 was synthesized through a condensation reaction of 4- aminopyridine-3-carbaldehyde and butane-2,3-dione.
- Janiak, Christoph,Deblon, Stephan,Uehlin, Lars
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p. 959 - 964
(2007/10/03)
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- Microwave spectrum, structure, and dipole moment of the trans-cis isomer of ethyl vinyl ether
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Microwave spectra of the trans-cis isomer of ethyl vinyl ether and its nine deuterated species were measured. A plausible molecular structure was obtained from the observed moments of inertia by an application of a diagnostic least-squares technique. The dipole moment and its direction were determined by the Stark effect measurements of several low J transitions for the normal and two deuterated species.
- Hayashi,Inada
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p. 195 - 204
(2007/10/02)
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- TRANSFORMATION OF PHENYLCHLORODIAZIRINES TO 1,3-DIOXOLANES AND A 1,3-DITHIOLANE
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Chlorophenylcarbene reacts with bifuncional or polyfuncional alcohols and ethanedithiol to form 2-phenyl-1,3-dioxolanes and 2-phenyl-1,3-dithiolane.
- Liu, Michael T.H.,Kokosi, Joseph
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p. 3049 - 3053
(2007/10/02)
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- Studies on the Mechanism of the Chlorohydrination of Olefins
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We studied the rate-determining and the product-determining steps of the chlorohydrination of olefins with Cl2/H2O and HOCl.In competitive kinetic experiments with 3-ethylpent-2-ene and cyclohexene we determined the relative rate constants krel=1,5 (with Cl2/H2O) and krel=infinite (with HOCl).This shows that the rate-determining steps of the chlorohydrination with Cl2/H2O and with HOCl are different.In order to investigate the product-determining steps we determined the proportion of alkyl-(2-chloroethyl)-ethers 3 and ethylene chlorohydrine 2 in the reaction of ethylene with Cl2 and with HOCl in alcohol/water-mixtures.The proportion of both the reaction products 3/2 was independent of the chlorinating agent used.Also the proportion of MARKOVNIKOV and anti-MARKOVNIKOV products in the chlorohydrination of propylene with Cl2/H2O or HOCl was independent of the type of chlorinating agent.In the chlorohydrination of cyclohexene both agents (Cl2/H2O and HOCl) yielded only the trans-chlorohydrine.From the results obtained it may be concluded that the product-determining step of chlorohydrination is the same for both the chlorinating agents studied.
- Buss, E.,Rockstuhl, A.,Schnurpfeil, D.
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p. 197 - 208
(2007/10/02)
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