نتایج جستجو برای: pyrimidines

تعداد نتایج: 6345  

2014
Vinita Sharma Nitin Chitranshi Ajay Kumar Agarwal

Microbes are unique creatures that adapt to varying lifestyles and environment resistance in extreme or adverse conditions. The genetic architecture of microbe may bear a significant signature not only in the sequences position, but also in the lifestyle to which it is adapted. It becomes a challenge for the society to find new chemical entities which can treat microbial infections. The present...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1975
F Skoog R Y Schmitz S M Hecht R B Frye

Ten substituted pyrrolo[2,3-d]pyrimidines were tested as cytokinins and anticytokinins in the tobacco bioassay. Eight new anticytokinins were identified and two were found to be highly active. The most potent species were 4-cyclohexylamino- and 4-cyclopentylamino-2-methylthiopyrrolo[2,3-d]pyrimidine, of which 0.05 and 0.009 muM concentrations, respectively, were required to produce detectable i...

2013
Jean-François Ritt Frédéric Raymond Philippe Leprohon Danielle Légaré Jacques Corbeil Marc Ouellette

BACKGROUND The human protozoan parasites Leishmania are prototrophic for pyrimidines with the ability of both de novo biosynthesis and uptake of pyrimidines. METHODOLOGY/PRINCIPAL FINDINGS Five independent L. infantum mutants were selected for resistance to the pyrimidine analogue 5-fluorouracil (5-FU) in the hope to better understand the metabolism of pyrimidine in Leishmania. Analysis of th...

Journal: :Biochemical Society transactions 1995
V Rubio J Cervera

Enzymatic synthesis of carbamoyl phosphate Carbamoyl phosphate is synthesized irreversibly by carbamoyl-phosphate synthase (CPS; EC6.3.4.16 and EC 6.3.5.5) in the first step of the routes of biosynthesis of pyrimidines, arginine and urea. In most bacteria, including Escherichia cofi, the same CPS is used for arginine and pyrimidine synthesis, whereas in higher organisms different CPS enzymes ar...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Anthony Mazurek Christopher N Johnson Markus W Germann Richard Fishel

Numerous DNA mismatches and lesions activate MutS homologue (MSH) ATPase activity that is essential for mismatch repair (MMR). We have found that a mismatch embedded in a nearest-neighbor sequence context containing symmetric 3'-purines (2 x 3'-purines) enhanced, whereas symmetric 3'-pyrimidines (2 x 3'-pyrimidines) reduced, hMSH2-hMSH6 ATPase activation. The 3'-purine/pyrimidine effect was mos...

2006
Kerstin Bischoff Ulrich Girreser Dieter Heber Martin Schütt

The Mannich reaction of 7-aryl-5,6-dihydropyrido[2,3-d]pyrimidines 3, easily accessible by condensation of 6-amino-1,3-dimethyluracil (1) with Mannich bases 2a – c, gives rise to a mixture of 7-aryl-6-(N,N-dimethylaminomethyl)pyrido[2,3-d]pyrimidines 6 and 7 as well as 1,2-bis(7-arylpyrido[2,3-d]pyrimidin-6-yl)ethane 13 the ratio of which depends on the reaction conditions and the amine used. 6...

2012
M. M. KANDEEL ASHRAF A. MOUNIR HANAN M. REFAAT ASMAA E. KASSAB

In continuation to our research program concerned with structural modification of thieno[2,3-d]pyrimidines with the purpose of enhancing their anticancer activity, various series of hexahydrocycloocta[4,5]thieno[2,3-d]pyrimidin-4-ones, hexahydrocycloocta[4,5]thieno[3,2-e]-1,2,4triazolo[4,3-c]pyrimidine-3(2H)-thiones and 4-substituted hydrazinylhexahydrocycloocta[4,5]thieno[2,3-d]pyrimidines wer...

Journal: :Biochemical pharmacology 1994
T E Renau J S Lee H Kim C G Young L L Wotring L B Townsend J C Drach

Non-nucleoside analogs of the pyrrolopyrimidine nucleosides toyocamycin, sangivamycin and thiosangivamycin have been synthesized and their cytotoxicity in mammalian cells determined. While studying the effects of 5-thioamide-substituted analogs on cell growth, we observed an interesting phenomenon in which cells recovered spontaneously from growth inhibition during extended incubations. HPLC st...

Journal: :Angewandte Chemie 2021

We report a novel and general method to access highly under-studied privileged scaffold—pyrimidines bearing trifluoroborate at C4, highlight the broad utility of these intermediates in rich array downstream functionalization reactions. This chemistry is underpinned by unique features group; its robustness provides an opportunity carry out chemoselective reactions other positions on pyrimidine w...

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