- 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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- Synthesis and degradation of nucleic acid components by formamide and iron sulfur minerals
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We describe the one-pot synthesis of a large panel of nucleic bases and related compounds from formamide in the presence of iron sulfur and iron-copper sulfur minerals as catalysts. The major products observed are purine, 1H-pyrimidinone, isocytosine, adenine, 2-aminopurine, carbodiimide, urea, and oxalic acid. Isocytosine and 2-aminopurine may recognize natural nucleobases by Watson-Crick and reverse Watson-Crick interactions, thus suggesting novel scenarios for the origin of primordial nucleic acids. Since the major problem in the origin of informational polymers is the instability of their precursors, we also investigate the effects of iron sulfur and iron-copper sulfur minerals on the stability of ribooligonucleotides in formamide and in water. All of the iron sulfur and iron-copper sulfur minerals stimulated degradation of RNA. The relevance of these findings with respect to the origin of informational polymers is discussed.
- Saladino, Raffaele,Neri, Veronica,Crestini, Claudia,Costanzo, Giovanna,Graciotti, Michele,Di Mauro, Ernesto
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experimental part
p. 15512 - 15518
(2009/03/12)
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- Nucleoside analogue phosphates for topical use
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Compositions for topical use in herpes virus infections comprising anti-herpes nucleoside analogue phosphate esters, such as acyclovir monophosphate, acyclovir diphosphate, and acyclovir triphosphate which show increased activity against native strains of herpes virus as well as against resistant strains, particularly thymidine kinase negative strains of virus. Also disclosed are methods for treatment of herpes infections with nucleoside phosphates. Anti-herpes nucleoside analogues phosphate esters include the phosphoramidates and phosphothiorates, as well as polyphosphates comprising C and S bridging atoms.
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- 4'-substituted nucleosides
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Nucleosides compounds of Formula I: STR1 wherein B is a purine or a pyrimidine; X and X' are H; Y is H; Y' is OH, F or H; or Y' and X' together makes a bond; Z is STR2 where n is zero, one, two or three; or Y' and Z together form a cyclic phosphate ester; Z' is --CN, --CH3, CH2 N3 or --CH2 J, where J is a halogen atom; or Z' and Y' together are --CH2 O--; and pharmaceutically acceptable esters, ethers, amides, N-acyl moieties and salts thereof.
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- Artificial DNA base pair analogues
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The present invention is directed to new artificial base pairs comprising complementary artificial purines and pyrimidines and methods of using artificial complementary base pairs.
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- Catalytic hydrogenation of 2-amino-6-chloropurine
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A process for the preparation of a compound of formula (I): STR1 which process comprises the reduction of a compound of formula (II): STR2 by catalytic hydrogenation using palladium on charcoal as catalyst.
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- Hydrolysis of 2-Aminopurine Deoxyribonucleoside in Neutral Solution
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At various temperatures between 50 and 110 deg C, 2-aminopurine deoxyribonucleoside is severalfold more prone to degradation in aqueous sodium cacodylate buffer, pH 6.9, than is its structural isomer, deoxyadenosine, as determined by HPLC analysis of hydrolysates.It is calculated that, at 37 deg C, the rate of hydrolysis of 2-aminopurine deoxyribonucleoside is 5 times as large as the rate of hydrolysis of deoxyadenosine.The decomposition of 2-aminopurine deoxyribonucleoside is almost unaffected by changes in ionic strength or buffer concentration, but is clearly accelerated by increasing acidity in the range from pH 5.8 to pH 7.15.While deoxyadenosine decomposes to produce the corresponding free base, adenine, as the sole UV-absorbing product, 2-aminopurine deoxyribonucleoside yields primarily 2,4-diamino-5-formamidopyrimidine rather than 2-aminopurine.The latter compound is also formed during hydrolysis of 2-aminopurine deoxyribonucleoside, but it arises largely in a secondary reaction from 2,4-diamino-5-formamidopyrimidine.The increased propensity to depurination evinced by 2-aminopurine deoxyribonucleoside in comparison to deoxyadenosine as well as the alteration of the heterocyclic base occurring during the hydrolysis is of interest in view of the mutagenic activity of 2-aminopurine.
- Ratsep, Peter C.,Pless, Reynaldo C.
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p. 3241 - 3246
(2007/10/02)
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- Preparative electrochemical reduction of 2-amino-6-chloropurine and synthesis of 6-deoxyacyclovir, a fluorescent substrate of xanthine oxidase and a prodrug of acyclovir.
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D.c. polarography of 2-amino-6-chloropurine in aqueous medium over a broad pH range revealed two diffusion waves, the first of which corresponds to reduction of the C(6)-Cl bond, leading to formation of 2-aminopurine in high yield. Condensation of the sodium salt of 2-aminopurine with (2-acetoxyethoxy)methyl chloride led to the two isomeric 9- and 7-(2-hydroxyethoxymethyl)-2-aminopurines. The 9- isomer, 6-deoxyacyclovir, a prodrug of acyclovir previously synthesized by another route, was readily converted to the latter by xanthine oxidase; the 7-isomer was not a substrate. The intense fluorescence of 6-deoxyacyclovir makes it a convenient fluorescent substrate for xanthine oxidase, although less sensitive than xanthine; it is shown that 2-aminopurine would be a very sensitive fluorescent substrate. The polarographic behaviour of the riboside of 2-amino-6-chloropurine was virtually identical with that of the parent purine, leading to a simple procedure for conversion of 2-amino-6-chloropurine nucleosides and acyclonucleosides to the corresponding 2-aminopurine congeners.
- Kusmierek,Czochralska,Johansson,Shugar
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p. 701 - 707
(2007/10/02)
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- DEAMINATION, INVOLVING RING OPENING, IN REACTIONS OF 1-AMINOPURINIUM MESITYLENESULFONATES WITH METHANOLIC AMMONIA
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On reaction of 1-aminopurinium mesitylenesulfonates with methanolic ammonia N-deamination occurs.For 1-amino-, 1-amino-8-(methylthio)-, 1-amino-8-phenyl-, 1-amino-2-methyl-, 1-amino-6-methyl- and 1-amino-8-phenyl-9-methylpurinium mesitylenesulfonate this reaction proceeds for at least 75percent via ring opening as shown by the isolation of 1-15N-labelled purines when 15N-labelled methanolic ammonia was used. 1-Amino-9-methylpurinium mesitylenesulfonate gave N-deamination without ring opening.The reaction of 1-amino-6-(methylthio)purinium mesitylenesulfonate with methanolic ammonia involves, besides deamination, partial substitution of the methylthio group; no ring opening is involved.However, ring opening followed by substitution occurs in the reaction of 1-amino-2-(methylthio)purinium mesitylenesulfonate; the reaction proceeds via an adduct at position 2.
- Kos, N. J.,Jongejan, H.,van der Plas, H. C.
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p. 4841 - 4848
(2007/10/02)
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- A 15N-STUDY ON THE DEAMINATION OF 1-AMINOPURINIUM SALTS WITH AMINES
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Reaction of 1-aminoadenosinium mesitylenesulphonate, 1a, with methanolic ammonia for 10 h at 80 deg C yields adenosine, 7a, and nebularine, 6a.With methanolic methylamine 1a gives 6-methylamino-9-β-D-ribofuranosylpurine, 8a, and adenosine, 7a, respectively.Similar results are obtained with the salt of 1-amino-2',3'-O-isopropylideneadenosine, 1b. 1-Aminoadeninium mesitylenesulphonate, 1c, with methanolic methylamine only yields 6-(methylamino)purine, 8c.In contrast, the mesitylenesulphonate salt of 1,2-diaminopurine, 11, with methanolic methylamine gives only deamination at N1, affording 2-aminopurine, 12.Studies with 15N-labelled methanolic ammonia or 15N-labelled purinium compounds show that in all these reactions, except that of 11, a ring-opening mechanism (ANRORC-mechanism) is involved.
- Kos, Nico J.,Jongejan, Hugo,Plas, Henk C. van der
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p. 369 - 374
(2007/10/02)
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- A 15N study of the ammonia-induced deamination of 1-aminopurinium salts
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Reaction of 1-aminoadeninium mesitylenesulfonate (1) and 1,2-diaminopurinium mesitylenesulfonate (8) with methanolic ammonia for 17 h at 100 deg C leads to deamination at N(1), yielding adenine and 2-aminopurine, respectively, as well as dideamination, yielding purine.It is very likely that 6-hydrazinopurine is formed in the dideamination of 1 and that 2- hydrazinopurine is an intermediate in the dideamination of 8.From both hydrazinopurines, purine is formed.Labelling studies, using 15N-labelled methanolic ammonia, show that, in the deamination reactions, a ring-opening reaction (ANRORC mechanism) is involved.
- Jongejan, H.,Kos, N. J.,Plas, H. C. van der
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p. 337 - 340
(2007/10/02)
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- NEW SYNTHETIC APPROACH FOR AZOLOPURINES AND ANALOGS
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A new synthetic approach has been developed for the synthesis of some azolopurines, i.e. derivatives of 1,2,4-triazolo(3,4-b)purine (3) and pyrrolo(2,1-b)purine (8), and for some pyrazolo(3,4-d)pyrimidines (12,14).
- Tisler, Miha,Stanovnik, Branko,Zrimsek, Zdenka
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p. 405 - 411
(2007/10/02)
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- Occurrence of the SNANRORC Mechanism in the Amination of 2-Substituted Purines with Potassium Amide in Liquid Ammonia
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The reactions of 2-chloro-, 2-fluoro- and 2-(methylthio)purine with potassium amide in liquid ammonia lead to the formation of 2-aminopurine.When these reactions are carried out with 15N-labeled potassium amide, ring-labeled 2-aminopurine is found.This demonstrates that a ring opening occurs during the amination.Formation of an anionic ? adduct at position 6 is proven by low-temperature NMR spectroscopy, and evidence is obtained for the formation of an open-chain intermediate, although this intermediate could not be isolated in a pure state.Reaction of the open-chain intermediate with hydriodic acid gives the thus far unknown 2-iodopurine. 2-Chloro-6-phenylpurine also reacts via ring opening into 2-amino-6-phenylpurine.However, 2-chloro-6-methyl- and 2-chloro-6,8-di-tert-butylpurine are found to be unreactive.
- Kos, Nico J.,Plas, Henk C. van der
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p. 2942 - 2945
(2007/10/02)
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