- Practical and Selective sp3 C?H Bond Chlorination via Aminium Radicals
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The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine-tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site-selective chlorination of sp3 C?H bonds. This process exploits the ability of protonated N-chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical-chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H-atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp3 C?H chlorination.
- McMillan, Alastair J.,Sieńkowska, Martyna,Di Lorenzo, Piero,Gransbury, Gemma K.,Chilton, Nicholas F.,Salamone, Michela,Ruffoni, Alessandro,Bietti, Massimo,Leonori, Daniele
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supporting information
p. 7132 - 7139
(2021/03/03)
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- Reaction of aldimine anions with vinamidinium chloride: Three-component access to 3-alkylpyridines and 3-alkylpyridinium salts and access to 2-alkyl glutaconaldehyde derivatives
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(Chemical Equation Presented) N-tert-Butylimino derivatives of aldehydes were deprotonated with LDA and reacted with vinamidinium chloride to give 2-alkylaminopentadienimine derivatives, which were isolated as their corresponding hydrochloride in 68-81% yield. Reaction of these derivatives with ammonium acetate or salts of primary amines, in n-butanol at 80°C, afforded the corresponding 3-alkylpyridines or 3-alkylpyridinium salts in high yield. Alkaline hydrolysis of 2-alkylaminopentadieneimine derivatives allowed a practical accesss to potassium salts of 2-alkylglutaconaldehyde.
- Wypych, Jean-Charles,Nguyen, Tuan Minh,Benechie, Michel,Marazano, Christian
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p. 1169 - 1172
(2008/09/18)
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- Synthesis and antiviral evaluation of 6-(alkyl-heteroaryl)furo[2,3-d] pyrimidin-2(3H)-one nucleosides and analogues with ethynyl, ethenyl, and ethyl spacers at C6 of the furopyrimidine core
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Sonogashira coupling strategies were employed to synthesize new furo[2,3-d]pyrimidin-2(3H)-one (FuPyrm) 2′-deoxynucleoside analogues. Partial or complete reduction of ethyne-linked compounds afforded ethenyl-and ethyl-linked derivatives. Levels of inhibition of varicella-zoster virus (VZV), human cytomegalovirus (HCMV), a broad range of other DNA and RNA viruses, and several cancer cell lines were evaluated in cell cultures. The anti-VZV potency decreased with increasing rigidity of the side chain at C6 of the FuPyrm ring in the order dec-1-yn-1-yl dec-1-en-1-yl decan-1-yl. In contrast, compounds with a rigid ethynyl spacer between C6 of the FuPyrm ring and a 4-alkylphenyl moiety were more potent inhibitors of VZV than the corresponding derivatives with an ethyl spacer. Replacement of the phenyl moiety in 6-(4-alkylphenyl) derivatives with a pyridine ring (in either regioisomeric orientation) gave analogues with increased solubility in methanol but reduced anti-VZV potency, and replacement with a pyrimidine ring reduced the anti-VZV activity even further. The pyridine-ring-containing analogues were ~20-fold more potent inhibitors of VZV than acyclovir but were ~6-fold less potent than BVDU and ~60-fold weaker than the most active 6-(4-pentylphenyl)- substituted prototype.
- Robins, Morris J.,Nowak, Ireneusz,Rajwanshi, Vivek K.,Miranda, Karl,Cannon, John F.,Peterson, Matt A.,Andrei, Graciela,Snoeck, Robert,De Clercq, Erik,Balzarini, Jan
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p. 3897 - 3905
(2008/02/10)
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- BIS-PYRIDINIUM COMPOUNDS
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A method of treating, inhibiting, or preventing an infection in a subject is described. The method comprises administering to the subject an effective amount of at least one bis-pyridinium compound. The bis-pyridinium compound comprises two aromatic ring structures. Each of the ring structures comprises a pyridine ring, and the ring structures are linked by a linker group of at least 8 atoms in length, said linker group being attached to the nitrogen atoms of the pyridine rings. At least one substituent on at least one of the ring structures is an alkyl group having at least 2 carbon atoms, and no substituent on either of the ring structures is -OH, -SH or an amine group.
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Page/Page column 21-22
(2008/06/13)
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- Formation of 2-Pentylpyridine from the Thermal Interaction of Amino Acids and 2,4-Decadienal
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To study the mechanism of 2-pentylpyridine formation in model systems, 2,4-decadienal was reacted with five amino acids (glycine, aspartic acid, asparagine, glutamic acid, and glutamine) at 180°C for 1 h (pH 7.5). In addition to 2-pentylpyridine, 3-pentylpyridine was also tentatively identified from the thermal reactions. The relative yields of alkylpyridine formation from the reactions were asparagine > glutamine > aspartic acid > glutamic acid > glycine. When amide-15N-labeled glutamine and asparagine were heated with 2,4-decadienal, the relative contribution of amide nitrogens to the formation of alkylpyridine was determined. Approximately half of nitrogen atoms in 2-pentylpyridine formed were contributed by the amide nitrogens of asparagine, whereas almost all of them came from the amide nitrogens in glutamine. The results above may indicate that both free ammonia and α-amino groups bound in amino acids can contribute to the formation of alkylpyridines, but free ammonia does so more effectively.
- Kim, Young-Suk,Hartman, Thomas G.,Ho, Chi-Tang
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p. 3906 - 3908
(2007/10/03)
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- New Synthesis of 3-Alkylpyridines
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An effective method is reported for preparation of 3-alkylpyridines from piperidine and C1-C10 aliphatic alcohols at 300-500 deg C in the presence of a dehydrogenating catalyst.
- Tereshko, A. B.,Tarasevich, V. A.,Kozlov, N. G.
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p. 258 - 259
(2007/10/03)
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- SYNTHESIS OF 3-N-BUTYLPYRIDINE - A TOXIC METABOLITE OF THE FUNGUS Fusarium oxysporum AND ITS HOMOLOGUES
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The interaction of the tri-n-butylphosphine complex of lithium di(3-pyridyl) copper(I) with 1-iodobutane and with other alkyl halides in ether at room temperature has given 3-n-butylpyridine and its homologues with yields of 82-89 percent.
- Goshaev, M. G.
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p. 391 - 393
(2007/10/02)
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- Reactions of 1,4-Bis(trimethylsilyl)-1,4-dihydropyridines with Carbonyl Compounds: A New Method for Regioselective Synthesis of 3-Alkylpyridines
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A new method for the alkyl group introduction at the 3-position of pyridines is described: Reductive disilylation of pyridine, its 2-methyl, 3-methyl, and 4-methyl derivatives affords the corresponding 1,4-disilyl-1,4-dihydropyridines.Tn the presence of a catalytic amount of tetrabutylammonium fluoride, these dihydropyridines smoothly react with a variety of aldehydes and ketones to give 3-alkylpyridines.
- Tsuge, Otohiko,Kanemasa, Shuji,Naritomi, Toshio,Tanaka, Junji
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p. 1497 - 1504
(2007/10/02)
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- REGIOSELECTIVE ALKYL GROUP INTRODUCTION AT THE 3-POSITION OF PYRIDINE VIA 1,4-BIS(TRIMETHYLSILYL)-1,4-DIHYDROPYRIDINE
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The reaction of 1,4-bis(trimethylsilyl)-1,4-dihydropyridine with aldehydes and ketones in the presence of tetrabutylammonium fluoride offers a convenient method for the preparation of 3-alkylpyridines.
- Tsuge, Otohiko,Kanemasa, Shuji,Naritomi, Toshio,Tanaka, Junji
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p. 1255 - 1258
(2007/10/02)
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- Ligand interaction of sustituted pyridines with cytochrome P-450.
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A series of pyridyl ketones and alkyl pyridines was evaluated as type II ligands for cytochrome P-450. Activity as type II ligands was evaluated in terms of the lipid solubility and the pKa values of the compounds.
- Born,Early
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p. 850 - 851
(2007/10/02)
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