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Pyrimidine System (pyrimidine + system)
Selected AbstractsChemInform Abstract: Construction of a Pyrido[4,3-d]pyrimidine System on the Basis of N-Cyanobenzamidine and Diethyl Acetone-1,3-dicarboxylate.CHEMINFORM, Issue 39 2008A. V. Komkov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis and Antitumor Evaluation of New Polysubstituted Thiazole and Derived Thiazolo[4,5-d]pyrimidine Systems.CHEMINFORM, Issue 44 2002Hesham T. Y. Fahmy Abstract For Abstract see ChemInform Abstract in Full Text. [source] Application of Selective Palladium-Mediated Functionalization of the Pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine Heterocyclic System for the Total Synthesis of Variolin B and Deoxyvariolin B,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2010Alejandro Baeza Abstract The reaction of protected 3-bromo-2-(bromomethyl)-4-methoxypyrrolo[2,3- b]pyridine and tosylmethyl isocyanide (TosMIC) afforded a pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine derivative in good yield. This compound was transformed through installation of the pyrimidine moiety in the C5 position, hydrolysis, and decarboxylation in an advanced intermediate for the total or formal synthesis of the naturalalkaloid variolin B. Reaction of 3-bromo-2-(bromomethyl)-4-chloropyrrolo[2,3- b]pyridine with N -tosylmethyl dichloroformimide as a synthetic TosMIC equivalent afforded trihalo-substituted pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine. This compound was used in a new total synthesis of the alkaloid variolin B by selective and sequential C,N, C,C, and C,O palladium-mediated functionalization at the C9, C5, and C4 positions of the pyrido[3,,2,:4,5]pyrrolo[1,2- c]pyrimidine system. A formal synthesis of deoxyvariolin B is also described by using the same synthetic strategy. [source] Synthesis and biological evaluation of carbon-11-labeled acyclic and furo[2,3-d]pyrimidine derivatives of bicyclic nucleoside analogues (BCNAs) for structure,brain uptake relationship study of BCNA tracersJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 3 2008Satish K. Chitneni Abstract We reported earlier on radiolabeled alkoxyphenyl bicyclic nucleoside analogues (BCNAs) as potential positron emission tomography (PET) reporter probes for imaging of varicella zoster virus thymidine kinase (VZV-tk) gene in vivo. Despite their favorable physicochemical properties, these tracers are not taken up in the brain in mice. In order to probe the role of the deoxyribose sugar moiety in blood-brain barrier (BBB) penetration of these molecules, we have synthesized and evaluated a carbon-11-labeled acyclic bicyclic nucleoside derivative ([11C]-10) where the 2,-deoxyribose sugar is replaced with a (2-hydroxyethoxy)methyl group and [11C]-12, which has no sugar moiety but a [11C]methyl group on the N-3 position of the pyrimidine ring. Methylation was achieved on the phenol ([11C]-10) or the N-3 position ([11C]-12) using [11C]methyl triflate (radiosynthesis). The (non-radioactive) acyclic O -methyl derivative 10 has rather poor affinity for the enzyme VZV-TK in vitro (IC50: 430,µM), compared with the moderate affinity of the BCNA-base N -methyl derivative 12 (IC50: 79,µM). In normal mice, none of the two tracers ([11C]-10 or [11C]-12) showed significant uptake in the brain, suggesting that compounds containing a furo[2,3- d]pyrimidine system do not cross the BBB. Copyright © 2008 John Wiley & Sons, Ltd. [source] Pyrimidine as Constituent of Natural Biologically Active CompoundsCHEMISTRY & BIODIVERSITY, Issue 1 2005Irene This review describes the various manifestations of the pyrimidine system (alkylated, glycosylated, benzo-annelated.). These comprise pyrimidine nucleosides as well as alkaloids and antibiotics , some of them have been discovered and isolated from natural sources already long time ago, others have been reported very recently. A short overview on pyrimidine syntheses (prebiotic synthesis, biosynthesis, and metabolism) is given. The biological activities of most of the pyrimidine analogs are briefly described, and, in some cases, syntheses are formulated. [source] | ||||||||||