- 4-Substituted 1-acyloxypyridine-2(1H)-thiones: Experimental and computational studies of the substituent effect on electronic absorption spectra
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(Chemical Equation Presented) A series of eight 4-substituted 1-(adamantane-1-carbonyloxy)pyridine-2(1H)-thiones (1, X=H, OC7H 15, Me, CF3, SC3H7, CN, COOMe, and Cl) was prepared and characterized by UV-vis spectroscopy in MeCN and cyclohexane. The observed lowest energy transition, designated as πCS→ π*ring, exhibits a substantial substituent effect and λmax ranges from 333 (X=OC 7H15) to 415 nm (X=CN). Experimental λ max values for all esters except for 1b (X=OC7H 15) correlate with the σp - parameter (ρ = 0.41 ± 0.03, r2= 0.95). In contrast, the energy of the absorption band at about 295 nm, designated as πCS → π*CS, is practically substituent independent. Both absorption bands exhibit a modest negative solvatochromic effect. The experimental absorption energies correlate better with excitation energies calculated for N-acetyloxy analogues 2 with the ZINDO//DFT than with the TD-DFT//DFT method. Calculations for a series of 12 N-acetates 2 predict the most blueshifted π → π* transition for the alkoxy substituent and most red-shifted for the NO2 group relative to the parent 2a (X = H). 2009 American Chemical Society.
- Jankowiak, Aleksandra,Kaszynski, Piotr
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supporting information; experimental part
p. 7441 - 7448
(2010/01/16)
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- 2- [ (2-SUBSTITUTED) -IND0LIZIN-3-YL] -2-OXO-ACETAMIDE DERIVATIVES AS ANTIFUNGAL AGENTS
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The invention provides compounds of formula (I), and pharmaceutically acceptable salts thereof wherein: Rl, R2, R3, R4, R5, R6, R7, X and X1 are as defined herein. These compounds are useful in the manufacture of medicaments for use in the prevention or treatment of a fungal disease. Compounds of formula (I), and agriculturally acceptable salts thereof, may also be used as agricultural fungicides.
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Page/Page column 114
(2008/12/05)
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- Two new methods for 2,3-pyridyne formation
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The compounds 2-chloro-4-methoxypyridine and 4-methoxy-2-trifluoromethylsulfonyloxy-3-trimethylsilylpyridine were shown to be relatively efficient precursors for 4-methoxy-2,3-pyridyne as was evidenced by its trapping with furan, 2-methylfuran and 2-methoxyfuran. These findings constitute the first published report of the use of either directed-deprotonation or fluoride-induced elimination to prepare the reactive 2,3-pyridyne intermediate.
- Walters, Michael A.,Shay, John J.
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p. 7575 - 7578
(2007/10/02)
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