E-Gems

Brand Name(s) Aqua Gem E, Aquasol E, E-Gems, Key-E, Key-E Kaps Chemical Class NUTR-vitamin, fat soluble... 

Capsules E-Gems) 100 units, 600 units, 800 units, 1,000 units,... 

Figure 6.64. (a) Photo of a cm-scale SWNT forest, shown next to a matchstick for comparative purposes. Reproduced with permission from Hata, K. Futaba, D. N. Mizuno, K. Namai, T. Yumura, M. lijima, S. Science 2004, 306,1362. Copyright 2004 AAAS. (b) A proposed scheme for the laser ablative growth of SWNTs via metal oxide nanocluster catalysts. Reproduced with permission from Rummeli, M. H. Borowiak-Palen, E. Gemming, T. Pichler, T. Knupfer, M. Kalbac, M. Dunsch, L. lost, O. Silva, S. R. R Pompe, W. Buchner, B. Nano Lett. 2005, 5,1209. Copyright 2005 American Chemical Society. 

In order to test observational errors nsing a fnll sample of unblended spectral lines, the Monte-Carlo method with a generator of normally distributed numbers was used. For N = 2545 measurements of magnetic fields on four yellow supergiants Aqr, a Aqr, e Gem, e Peg), including weak unblended spectral lines, the relation between mean the Monte-Carlo simulated standard error and the mean experimental standard error was estimated as = 1.033<(t>. Further, weak spectral lines for which z ro - rj < 0.2 were eliminated to strengthen the data uniformity. For A= 1844 measurements = 0.968<(t>. The discrepancy is 3.3 % in the first case and 3.2 % in the second case both appear to be very small. 

Rtimmeli MH, Borowiak-Palen E, Gemming T, Pichler T, Knupfer M, Kalhac M, et al. Novel catalysts, room temperature, and the importance of oxygen for the synthesis of single-walled carbon nanotubes. Nano Lett 2005 5 1209-15. 

C. Mettenheimer, Corr.-Blatt d. Verein. E gem Arbeit zur Furderung d. wiss. Heilkunde, 24, 331 (1857). 

The majority of preparative methods which have been used for obtaining cyclopropane derivatives involve carbene addition to an olefmic bond, if acetylenes are used in the reaction, cyclopropenes are obtained. Heteroatom-substituted or vinyl cydopropanes come from alkenyl bromides or enol acetates (A. de Meijere, 1979 E. J. Corey, 1975 B E. Wenkert, 1970 A). The carbenes needed for cyclopropane syntheses can be obtained in situ by a-elimination of hydrogen halides with strong bases (R. Kdstcr, 1971 E.J. Corey, 1975 B), by copper catalyzed decomposition of diazo compounds (E. Wenkert, 1970 A S.D. Burke, 1979 N.J. Turro, 1966), or by reductive elimination of iodine from gem-diiodides (J. Nishimura, 1969 D. Wen-disch, 1971 J.M. Denis, 1972 H.E. Simmons, 1973 C. Girard, 1974),... 

Similar intermediates including o-ethoxycarbonyl-, o-cyano- and o-dimethyl-aminomethylene-piperidones or their imines have been used to give partially reduced analogues, e.g. (244), in the [2,3-. 

E-mail kolmak.chemicals gems.vsnl.net.in Web site www.kolmak.com... 

The preparation of e/n-difluoro compounds by the oxidative fluorodesul-furization ot 1,3-dithiolanes readily proceeds by treatment with a pyridinium polyhydrogen fluoride-Af-halo compound reagent the latter serves as a bromonium ion source [2], l,3-Dibromo-5,5-dimethylhydantoin is the most effective of several At-halo oxidants. It is believed that /V-halo compounds combine with hydrogen fluoride to generate in situ halogen fluorides, the oxidants. Formation of gem-difluorides from dithiolanes derived from ketones is efficient and rapid, even at -78 °C, whereas the reaction of dithiolanes derived from aldehydes requires higher temperature (0 °C) (equation 4). 

Gemeprost (73 16.16-dimethvl-trans-A -prostaglandin-E]) is dramatically more potent on a dosage basis as an abortifacient than prostaglandin E2 itself and has fewer side effects. The gem-dimethyl groups at C-16 protect the alcohol moiety at C-15 from rapid metabolic oxidation. 

The synthesis of vinylaziridines through reactions between allylic carbenoid reagents and imines (i.e., Darzen-type reactions) was first reported by Mauze in 1980 [13]. Treatment of aldimines or ketimines 16 with gem-chloro(methyl)allyllithium (17) afforded N-substituted vinylaziridines 18 (Scheme 2.6). Similarly, 2,3-trans-N-diphenylphosphinyl-2-vinylaziridines 21 were prepared with good stereoselectivities (trans cis= 10 1 Scheme 2.7) by treatment of a-bromoallyllithium (20) with N-diphenylphosphinyl aldimines 19 in the presence of zinc chloride [14]. 

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