- Photoinduced reduction of thymine and uracil derivatives by hypophosphite: Unusual high quantum yield of chromophore loss
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The quantum yield of chromophore loss of thymine, uracil and their corresponding nucleosides and nucleoside-5′-monophosphates undergoing irradiation with 254 nm UV light was found to be sharply enhanced by hypophosphite; thymine and uracil were reduced by hypophosphite to give 5,6-dihydrothymine and 5,6-dihydrouracil respectively.
- Wang, Kongjiang,Chai, Zhifang
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- Reactivity of damaged pyrimidines: Formation of a schiff base intermediate at the glycosidic bond of saturated dihydrouridine
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DNA glycosylases catalyze the first step of the base excision repair (BER) pathway. The chemistry used by these enzymes for deglycosylation has been largely considered as the chemistry of the oxocarbenium ion, e.g., direct rupture of the C1-N1 bond resulting in an oxocarbenium ion intermediate. Here we present mechanistic studies revealing the 2-deoxyribose isomerization and subsequent deglycosylation processes in two pyrimidine lesions: 5,6-dihydro-2-deoxyuridine (dHdU) and 5,6-dihydrothymidine (dHT), formed via ionizing radiation damage to 2-deoxycytidine and thymidine, respectively, under anoxic conditions. Acid or heat treatment of these two lesions leads to the production of two pairs of C1 epimers containing a pyranose and a furanose, respectively, indicating that both lesions favor the rupture of the C1-O4 bond, resulting in a Schiff base intermediate at the N-glycosidic bond. Such a Schiff base intermediate was trapped and characterized by either Pd-catalyzed hydrogenation or thiol-mediated addition reaction. In contrast, in undamaged 2-deoxyuridine and thymidine, reactions at elevated temperatures lead to the release of nucleobases most likely via the traditional oxocarbenium ion pathway. DFT calculations further support the experimental findings, suggesting that the oxocarbenium ion intermediate is responsible for the deglycosylation process if the integrity of the pyrimidine ring is maintained, while the Schiff base intermediate is preferred if the C5=C6 bond is saturated. Currently, the oxocarbenium ion pathway is indicated to be solely responsible for the deglycosylation in BER enzymes, however our results suggest an alternative Schiff base mechanism which may be responsible for the repair of saturated pyrimidine damages.
- Jian, Yajun,Lin, Gengjie,Chomicz, Lidia,Li, Lei
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- 4,5-Dihydroxyimidazolidin-2-ones in the α-ureidoalkylation reaction of N-(carboxyalkyl)-, N-(hydroxyalkyl)-, and N-(aminoalkyl)ureas 1. α-Ureidoalkylation of N-(carboxyalkyl)ureas
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The α-ureidoalkylation of N-(carboxyalkyl)ureas (ureido acids) with 1,3-H2 s-, 1,3-Me 2 s-, and 1,3-Et2 s-4,5-dihydroxyimidazolidin-2-ones was systematically studied. The yields of glycolur
- Kravchenko,Lyssenko,Chikunov,Belyakov,Il'In,Baranov,Nelyubina,Davankov,Pivina,Makhova,Antipin
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- BIFUNCTIONAL DEGRADERS AND THEIR METHODS OF USE
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Described herein are bifunctional degrader compounds, their various targets, their preparation, pharmaceutical compositions comprising them, and their use in the treatment of conditions, diseases, and disorders mediated by various target proteins.
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Page/Page column 315
(2021/04/01)
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- A uracil green production process
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The present invention provides a uracil green production process, comprising the following steps: 1) to thio uracil as raw materials, adding water, also adding halide or sulfonic acid compound, heating overnight, cooling, filtering and drying, to obtain high-purity uracil; 2) step 1) filtering the resulting stock solution continue adding thio uracil, heating, circulating the above-mentioned operation. The invention has the following advantages: the reaction mother liquor and material can be applied mechanically, and yield and purity is not affected, is a environmental friendly technology. High purity can be obtained uracil, namely detection HPLC purity of 95% or more, or even 98% or more of the uracil.
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Paragraph 0035-0048
(2018/07/30)
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- Mechanochemical preparation of hydantoins from amino esters: Application to the synthesis of the antiepileptic drug phenytoin
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The eco-friendly preparation of 5- and 5,5-disubstituted hydantoins from various amino ester hydrochlorides and potassium cyanate in a planetary ball-mill is described. The one-pot/two-step protocol consisted in the formation of ureido ester intermediates, followed by a base-catalyzed cyclization to hydantoins. This easy-handling mechanochemical methodology was applied to a large variety of α- and β-amino esters, in smooth conditions, leading to hydantoins in good yields and with no need of purification steps. As an example, the methodology was applied to the "green" synthesis of the antiepileptic drug Phenytoin, with no use of any harmful organic solvent.
- Konnert, Laure,Reneaud, Benjamin,De Figueiredo, Renata Marcia,Campagne, Jean-Marc,Lamaty, Frdric,Martinez, Jean,Colacino, Evelina
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p. 10132 - 10142
(2015/02/19)
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- Regioselective reactions of N-(carboxyalkyl)- and N-(aminoethyl)ureas with glyoxal and 1,2-dioxo-1,2-diphenylethane
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Regioselective reactions of N-(carboxyalkyl)ureas (ureido acids) and N-(aminoethyl)ureas with 1,2-dioxo-1,2-diphenylethane (benzyl) and glyoxal are studied in detail. The structure of the reactants affects the reaction regioselectivity. Acid-catalyzed rea
- Kravchenko,Baranov,Gazieva,Chikunov,Nelyubina
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p. 416 - 421
(2015/02/02)
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- Transfer hydrogenation as a redox process in nucleotides
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Using a combined theoretical and experimental strategy, the heats of hydrogenation of the nucleotide bases uracil, thymine, cytosine, adenine, and guanine have been determined. The most easily hydrogenated base is uracil, followed by thymine and cytosine. Comparison of these hydrogenation enthalpies with those of ketones and aldehydes derived from sugar models indicates the possibility of near-thermoneutral hydrogen transfer between uracil and the sugar phosphate backbone in oligonucleotides. (Figure Presented)
- Achrainer, Florian,Emel'yanenko, Vladimir N.,Tantawy, Waled,Verevkin, Sergey P.,Zipse, Hendrik
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p. 10426 - 10429
(2015/04/14)
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- Meteorites as catalysts for prebiotic chemistry
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From outer space: Twelve meteorite specimens, representative of their major classes, catalyse the synthesis of nucleobases, carboxylic acids, aminoacids and low-molecular-weight compounds from formamide (see figure). Different chemical pathways are identified, the yields are high for a prebiotic process and the products come in rich and composite panels.
- Saladino, Raffaele,Botta, Giorgia,Delfino, Michela,Di Mauro, Ernesto
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p. 16916 - 16922
(2014/01/06)
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- Dibutylphosphate (DBP) mediated synthesis of cyclic N,N′- disubstituted urea derivatives from amino esters: A comparative study
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The N,N′-disubstituted urea derivatives such as amino acid hydantoins and dihydrouracil derivatives were prepared starting from natural and unnatural amino acid esters using dibutylphosphate (DBP). During the attempted synthesis of N-heterocycles with larger than six-membered rings containing the N,N′-disubstituted urea functionalities, three unexpected products namely squamolone, N-methyl pyrrolidine-2-one, and diketopiperazine were isolated.
- Agrawal, Sumit K.,Sathe, Manisha,Kaushik, M. P.,Halve, A. K.
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supporting information
p. 5996 - 5999,4
(2020/08/20)
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- Specific features of the reaction of vanadyl acetylacetonate with tert-butyl hydroperoxide
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It was found for the first time that the reaction of N-(carboxyalkyl)ureas (ureido acids) with 4,5-dihydroxy-1,3-dimethyl-4,5-diphenylimidazolidin-2-one in methyl or isopropyl alcohol proceeds through the tandem sequence of α-ureidoalkylation and esterification to form the earlier unknown N-(carboxyalkyl)glycoluril methyl or isopropyl esters. N-(Carboxyalkyl)- glycolurils of a new-type substitution were obtained by alkaline hydrolysis of their isopropyl esters, the structure of one of them was confirmed by X-ray diffraction analysis.
- Stepovik, L. P.,Gulenova, M. V.
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scheme or table
p. 1427 - 1432
(2011/06/27)
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- Assembly/disassembly of drug conjugates using imide ligation
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A strategy is described that allows the easy assembly and controlled disassembly of drug conjugates. Imide ligation, that is, the reaction of a peptide thioacid with an azidoformate, is used for conjugate assembly. The imide bond participates also with an endopeptidase-triggered cyclization-based disassembly mechanism.
- Mhidia, Reda,Beziere, Nicolas,Blanpain, Annick,Pommery, Nicole,Melnyk, Oleg
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supporting information; experimental part
p. 3982 - 3985
(2010/11/02)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Improved chemical syntheses of 5,6-dihydro-5-fluorouracil
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(Chemical Equation Presented) 5,6-Dihydro-5-fluorouracil (5-DHFU) is a metabolite of the chemotherapy drug 5-fluorouracil (5-FU) of importance for biological studies. 5-DHFU has been prepared by enzymatic reduction of 5-FU and in very low yield by hydrogenation of 5-FU; however, a practical chemical synthesis is not available. Facile racemic syntheses of 5-DHFU from 5-FU or uracil, using p-methoxybenzyl protecting groups followed by L-Selectride reduction, are reported.
- LaFrate, Andrew L.,Katzenellenbogen, John A.
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p. 8573 - 8576
(2008/02/13)
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- NOVEL SALTS OF CONJUGATED PSYCHOTROPIC DRUGS AND PROCESSES OF PREPARING SAME
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Novel chemical conjugates of a psychotropic drug residue and an amino-containing organic acid residue selected to reduce side effects induced by the psychotropic drug when administered per se, to enhance the therapeutic activity of the psychotropic drug and/or to exert anti-proliferative activity, in which the amino group is in the form of an acid addition salt thereof and which are characterized by high stability are disclosed. Further disclosed are processes for preparing the chemical conjugates and addition salts thereof, pharmaceutical compositions containing the chemical conjugates and methods utilizing the chemical conjugates for treating various medical conditions.
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(2008/06/13)
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- Concomitant monoreduction and hydrogenation of unsaturated cyclic imides to lactams catalyzed by ruthenium compounds
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(Chemical Equation Presented) One for two: [Ru4H 6(p-cymene)4]Cl2 and [RuCl2(p- cymene)]2, [Ru], are efficient catalyst precursors for the selective transformation of cyclic imides into saturated lactams (see scheme). The catalytic systems operate with the same reagent (H2) to perform two transformations, namely, monoreduction of the carbonyl groups and hydrogenation of C=C bonds, with the release only of water, which is the solvent of the reaction.
- Aoun, Rimane,Renaud, Jean-Luc,Dixneuf, Pierre H.,Bruneau, Christian
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p. 2021 - 2023
(2007/10/03)
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- Dihydrobenzofuran derivatives, their production and use
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There are disclosed novel dihydrobenzofuran derivatives of the formula: STR1 wherein A, X, Y, Z, R1 and R2 are each as defined in the description. Also disclosed are a herbicidal composition containing a herbicidally effective amount of the compound (I) as an active ingredient and a method for exterminating unfavorable weeds by applying a herbicidally effective amount of the compound (I) to an area where the unfavorable weeds grow or will grow.
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- Oxidative Cyclization of Diamides by Phenyliodoso Acetate
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Carboxamides containing a suitably situated nucleophilic group (carboxamide, N-substituted carboxamide, or hydroxymethyl) undergo oxidation by phenyliodoso acetate to afford heterocyclic products through internal attack on the initially formed isocyanate.N-Substituted carboxamido groups are the least effective of these internal traps.Phenyliodoso acetate is much superior to lead(IV) acetate for oxidative cyclization of maleamide and various substituted propanediamides, but is not suitable for butanediamide.
- Beckwith, Athelstan L. J.,Dyall, Leonard K.
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p. 451 - 461
(2007/10/02)
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- A SELECTIVE AND EFFICIENT METHOD FOR THE DEPROTECTION OF N-BENZYLOXYMETHYL (BOM) PROTECTING GROUPS FROM PYRIMIDINE AND DIHYDROPYRIMIDINE RING SYSTEMS
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N1,N3-dibenzyloxymethyl derivatives of pyrimidines and dihydropyrimidines have been successfully deprotected by using trifluoroacetic acid (TFA).These N-BOM derivatives can be selectively removed from a variety of derivatives including nucleosides and compounds which are sensitive to base and reducing conditions.
- DeFrees, Shawn A.,Reddy, Kalakota S.,Cassady, John M.
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p. 213 - 220
(2007/10/02)
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- Reaction of Hydroxyalkyl Radicals with Uracil
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The base degradation yields when aqueous solutions of uracil containing methyl, ethyl or t-butyl alcohol were γ-irradiated, were 2.0 +/-0.2, 4.2 +/-0.5 and 1.3 +/-0.1, respectively.These differences are attributed to differences in reactivity of CH2OH (I)
- Bhattacharyya, Sudhindra N.,Mandal, Parikshit C.
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p. 2103 - 2110
(2007/10/02)
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- Reactions of some Free Radicals Derived from Uracil with Nickel(II) Compounds
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Reactions of Ni(II) compounds with the transient adducts of uracil, viz.U(1-) and UOH, have been studied in the steady-state radiolysis of uracil in the presence of different Ni(II) species, e.g.NiSO4, Ni(II)EDTA, Ni(II)NTA, Ni(II)IDA and Ni(II)(IDA)2.The U(1-) radicals formed by the reaction of uracil with e(1-)aq transfer an electron to the Ni(II) species.The redox behaviour of UOH radicals has been investigated by following the ligand-degradation products of the Ni(II) complexes and the degradation of the base.The ligand-degradation products, e.g. formaldehyde and glyoxalic acid, arise from the degradation of the metal complex through its oxidation to Ni(III) by C6-UOH radical species.Unlike Cu(II) or Fe(III) ions, Ni(II) ions have very little effect on the radiosensitivity of uracil.The radiosensitising ability of the metal ions, which is dependent on electron transfer from UOH to the metal ion, is correlated with the redox potential of the metal ion couple M(n+)/M((n-1)+).
- Bhattacharyya, Sudhindra N.,Mandal, Parikshit C.
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p. 1205 - 1216
(2007/10/02)
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- Certain pyrido-pyrimidines for treating mammalian and avian infections
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8-Substituted pyrido [2,3-d]pyrimidines having activity against microorganisms which utilize de novo synthesis of riboflavin.
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