Browsing by Subject "chemistry, organic"
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Item A Base Induced Transformation Of A 1,3-Dimethyl-1,3-Di-(1-Adamantyl)Formamidinium Salt Into Beta- Methyl-(1-Adamantyl)Amino Acrylonitriles In Aliphatic Nitriles(2012) Knishevitsky, Arthur V.; Korotkikh, Nikolai I.; Cowley, Alan H.; Moore, Jennifer A.; Vasudevan, Kalyan V.; Pekhtereva, Tatyana M.; Shvaika, Oles P.; Cowley, Alan H.; Moore, Jennifer A.; Vasudevan, Kalyan V.A novel 1,3-dimethyl-1,3-di-(1-adamantyl)formamidinium perchlorate has been prepared via the Vilsmeier-Haack reaction of N-methyl-N-(1-adamantyl)formamide and N-methyl-N-(1-adamantyl) amine in a mixture of phosphorus oxychloride and benzene. The new formamidinium salt was found to undergo addition-elimination reactions when treated with sodium hydride in acetonitrile or propionitrile solution, thereby forming the corresponding beta-[methyl(1-adamantyl)amino]acrylonitriles and N-methyl-N-(1-adamantyl) amine. The H-1 and C-13 NMR spectra and the single-crystal X-ray structure of the new formamidinium salt have been determined along with those of the related compound 1,3-di-(1-adamantyl)-1-cyanoamidine and the corresponding beta-(dialkylamino)acrylonitriles.Item Electrospray Ionization Mass Spectrometric Study Of The Metal Cation Complexation Capabilities Of A Novel, Doubly Cage-Annulated Molecular Box(2005) Sherman, Courtney L.; Brodbelt, Jennifer S.; Srinivas, Gadthula; Sivappa, Rasapalli; Marchand, Alan P.; Sherman, Courtney L.; Brodbelt, Jennifer S.An unusual molecular box, 4, obtained as a mixture of diastereoisomeric, doubly cage-annulated host molecules, i.e., 4a and 4b, has been prepared. The metal cation complexation properties of the mixture of 4a and 4b thereby obtained have been assessed, with comparison to another bis crown 2, via application of electrospray ionization mass spectrometric (ESI-MS) methods. Both host systems 2 and 4 bind selectively to Li+ and Na+, thereby demonstrating preference over the other larger alkali metals. Addition of Ag+ to the solutions containing alkali metals does not result in substantial Ag+ complexation. Analysis of a solution containing only transition metal, not alkali metal, cations indicates that 4 forms complexes with Zn+ and Ag+ along with substantial complexation of Na+ from residual sodium present in the solvents.Item Review: Stable Heteroaromatic Carbenes Of The Benzimidazole And 1,2,4-Triazole Series(2005) Korotkikh, Nikolai I.; Shvaika, Oles P.; Rayenko, Gennady F.; Kiselyov, Artyom V.; Knishevitsky, Arthur V.; Cowley, Alan H.; Jones, Jamie N.; Macdonald, Charles L. B.; Cowley, Alan H.; Jones, Jamie N.; Macdonald, Charles L. B.The review is focused on new data concerning the syntheses and selected properties of stable heteroaromatic monocarbenes of the benzimidazole and 1,2,4-triazole series, biscarbenes, anionocarbenes of the 1,2,4-triazole series, and cryptocarbenes. The syntheses of the precursors to these compounds are also described. Special attention is paid to C-H insertion reactions, X-ray structural data and spectral characteristics of the carbenes and their analogues.Item Synthesis of 2-Substituted 9-Oxa-Guanines {5-Aminooxazolo 5,4-D Pyrimidin-7(6H)-Ones} and 9-Oxa-2-Thio-Xanthines{5-Mercaptooxazolo 5,4-D Pyrimidin-7(6H)-Ones}(2008-07) Mandal, Subrata; Li, Wen Tai; Bai, Yan; Robertus, Jon D.; Kerwin, Sean M.; Mandal, Subrata; Li, Wen Tai; Bai, Yan; Robertus, Jon D.; Kerwin, Sean M.Oxazolo[5,4-d] pyrimidines can be considered as 9-oxa-purine analogs of naturally occurring nucleic acid bases. Interest in this ring system has increased due to recent reports of biologically active derivatives. In particular, 5-aminooxazolo[5,4-d]pyrimidine-7(6H)-ones (9-oxa-guanines) have been shown to inhibit ricin. The preparation of a series of 2-substituted 5-aminooxazolo[5,4-d] pyrimidin-7(6H)-ones and related 5-thio-oxazolo[5,4-d] pyrimidines is described, including analogs suitable for further elaboration employing "click" chemistry utilizing copper-catalyzed Huisgen 1,3-dipolar cycloadditions. Two of the compounds prepared were found to inhibit ricin with IC(50) ca. 1-3 mM.Item Synthesis Of Heteroaromatic 3,3 '-Bridged Biscarbenes Of The 1,2,4-Triazole Series And Their Properties(2008) Kiselyov, Artyom V.; Korotkikh, Nikolai I.; Cowley, Alan H.; Moore, Jennifer A.; Findlater, Michael A.; Pekhtereva, Tatyana M.; Shvaika, Oles P.; Cowley, Alan H.; Moore, Jennifer A.; Findlater, Michael A.The stable 3,3'-bridged biscarbenes, 1,4- and 1,3-bis[1-alkyl-4-phenyl-1,2,4-triazol-5-yliden-3yl] benzenes (5a,b,d) and 1,3-bis[1-(1-adamantyl)-4-phenyl-1,2,4-triazol-5-yliden-3-yl] butane (5c) have been prepared. Treatment of 5b with copper (I) chloride in tetrahydrofuran/acetonitrile solution and cobalt (II) chloride in acetonitrile or acetonitrile/toluene solution afforded the biscarbene copper (I) complex 8. The reactions of 5d with diphenyldiazomethane and sulfur resulted in the novel bisthione 6 and bisazine (7) derivatives, respectively. The X-ray crystal structures of 5d, 8 were determined.Item Tandem Transformations Of 1,2,4-Triazol-5-Ylidenes Into 5-Amidino-1,2,4-Triazoles(2007) Korotkikh, Nikolai I.; Glinyanaya, Natalia V.; Cowley, Alan H.; Moore, Jennifer A.; Knishevitsky, Arthur V.; Pekhtereva, Tatyana M.; Shvaika, Oles P.; Cowley, Alan H.; Moore, Jennifer A.The first tandem autotransformations of heteroaromatic carbenes have been found. These reactions involve cleavage of the 1-tert-butyl-3,4-diaryl-1,2,4-triazol-5-ylidenes 1a-d to form benzonitriles and the respective carbodiimides, followed by further reactions of the latter with carbenes 1a-d to afford the 3,4-diaryl-5-(1-tert-butyl-3-arylamidin- 2- yl)-1,2,4- triazoles 5a-d. The X-ray structures of the carbene 1-tert-butyl-3-phenyl-4-n-bromophenyl-1,2,4-triazol-5-ylidene (1a) and the amidinotriazole 3-phenyl-4-p-bromophenyl-5-(1-tert-butyl-3-p-bromophenylamidin-2-yl)- 1,2,4- triazole (5a) were determined. The reactions of 1a with the electrophiles diphenylcarbodiimide, acetonitrile, and diphenyldiazomethane are also described.