- Analysis of spectral parameters of trans- and cis-silyl substituted 1,2-dihalogenoethenes including one-bond CC spin-spin coupling constants across double bonds
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Some trans- and cis-1-trialkylsilyl-1,2-dihalogenoethenes have been synthesized and their 13C and 1H NMR spectra recorded.The compounds studied readily undergo reversible cis-trans isomerization, the cis isomers being thermodynamically more stable than the trans isomers.The value of 3J(SiHα)trans is about twice as large as that of 3J(SiHα)cis, and the values of 2J(CβHα)trans is about one-tenth that of 2J(CβHα)cis and this allows ready assignment of the configuration.The one-bond spin-spin coupling constants between the ethylenic carbons depend on the electronegativities of the substituents, trans 1J(C=C) in most cases being larger than 1J(C=C)cis.
- Kamienska-Trela, K.,Kania, L.,Sitkowski, J.,Bednarek, E.
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- Macamides and their synthetic analogs: Evaluation of in vitro FAAH inhibition
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Maca (Lepidium meyenii), a traditional food crop of the Peruvian Andes is now widely touted as a dietary supplement. Among the various chemical constituents isolated from the plant are a unique series of non-polar, long-chain fatty acid N-benzylamides known as macamides. We have synthesized 11 of the 19 reported macamides and have tested each as potential inhibitors of the human enzyme, fatty acid amide hydrolase (FAAH). The five most potent macamides were FAAH inhibitors (IC50 = 10-17 μM). These amides were derivatives of oleic, linoleic and linolenic acids and benzylamine or 3-methoxybenzylamine. Of the three compounds evaluated in a pre-incubation time study, two macamides were not irreversible inhibitors of FAAH. The third, a carbamate structurally related to macamides, was shown to be an irreversible inhibitor of FAAH (IC50 = 0.153 μM).
- Wu, Hui,Kelley, Charles J.,Pino-Figueroa, Alejandro,Vu, Huyen D.,Maher, Timothy J.
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p. 5188 - 5197
(2013/09/02)
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- HEI PHOTOELECTRON SPECTRA OF UNSTABLE MOLECULES: MONO- AND DIHALOGENOKETENES
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HeI Photoelectron spectra are reported for the mono- and di-chloro-and-bromo-ketenes (XHC=C=O and X2C=C=O, X=Cl,Br) generated in high yield as unstable molecules from thermolysis of acid halides.The spectra are discussed and assigned by reference to the parent ketene molecule, orbital trends, and comparison with theoretical calculations.
- Colbourne, David,Westwood, Nicholas P. C.
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p. 2049 - 2054
(2007/10/02)
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- REACTIONS OF CHLORINE MONOFLUORIDE. V. REGIOSPECIFICITY AND STEREOCHEMISTRY IN THE ADDITION OF CHLORINE MONOFLUORIDE TO E- AND Z-1-BROMO-2-CHLOROETHYLENES AND 1,2-DIBROMOETHYLENES
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The chlorofluorination of Z- and E-1-bromo-2-chloroethylenes and 1,2-dibromoethylenes with hexachloromelamine in anhydrous hydrogen fluoride and with chlorine monofluoride in Freon 113 was investigated.The addition of ClF at the multiple bond of alkenes is nonregiospecific and nonstereospecific.The direction and stereochemistry of addition depend on the reagent, the substrates, and the medium.The mechanism of chlorofluorination was examined, and it was shown that in both media the reaction takes place with the participation of chloronium and bromonium carbocationic intermediates.
- Boguslavskaya, L. S.,Ternovskoi, L. A.
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p. 1647 - 1652
(2007/10/02)
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