Nucleic acid related compounds. 67. Synthesis of 5′-amino and 5′-methylthio chain-extended nucleosides from uridine

1991 ◽  
Vol 69 (12) ◽  
pp. 2104-2111 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
N. Kent Dalley ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Sodium Borohydride ◽  
Conjugate Addition ◽  
Amino Derivative ◽  
Vinyl Sulfone ◽  
X Ray ◽  
Basic Solutions ◽  
High Yields ◽  
Wittig Reagent ◽  
Related Compounds

Treatment of 2′,3′-O-isopropylideneuridine-5′-aldehyde with the stabilized Wittig reagent, (p-toluenesulfonylmethylene)triphenylphosphorane, gave high yields of 1-[5,6-dideoxy-2,3-O-isopropylidene-6-(p-toluenesulfonyl)-β-D-ribo-hex-5(E)-enofuranosyl]uracil (2). This vinylsulfone (2) underwent isomerization readily in base to give the allylic sulfone, 1-[5,6-dideoxy-2,3-O-isopropylidene-6-(p-toluenesulfonyl)-β-D-erythro-hex-4(Z)-enofuranosyl]uracil (3). Treatment of 2 or 3 with aqueous trifluoroacetic acid gave the corresponding deprotected vinyl (5) or allylic (6) sulfones, and 5 was converted to 6 readily in basic solutions. Treatment of 2 with sodium borohydride, sodium thiomethoxide, or ammonia resulted in conjugate addition (at C5′ of the vinyl sulfone) to give the 5′-hydro, 5′-methylthio, or 5′-amino-5′,6′-dideoxy-6′-(p-toluenesulfonyl) nucleosides. The 5′-substituted diastereomers were deprotected, separated, and the configuration of a 5′-amino derivative was established by X-ray crystallography.Key words: allylic sulfones, amino-nucleosides, 5′,6′-dideoxynucleosides, nucleosides, uridine, vinyl sulfones.

Nucleic acid related compounds. 63. Synthesis of 5′-deoxy-5′-methyleneadenosine and related Wittig-extended nucleosides

1991 ◽  
Vol 69 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Key Words ◽  
Organic Bases ◽  
Key Words Adenosine ◽  
Tosyl Group ◽  
High Yields ◽  
Related Compounds

Treatment of the purified 5′-aldehyde (2a) (derived from 6-N-benzoyl-2′,3′-O-isopropylideneadenosine (1a)) with methylenetriphenylphosphorane and successive deprotection with ammonia and acid gave 9-(5,6-dideoxy-β-D-ribo-hex-5-enofuranosyl)adenine (5′-deoxy-5′-methyleneadenosine) (4). Oxidation of 1a or 2′,3′-O-isopropylideneadenosine (1b) and treatment of the crude 5′-aldehydes (2a or 2b) with (p-toluenesulfonylmethylene)triphenylphosphorane gave high yields of the 5′-deoxy-5′-tosylmethylene derivatives (5a or 5b). Removal of the tosyl group from 5b to give 3b was effected with tributylstannyllithium, but sulfone cleavage by the usual reductive methods failed. Reduction and deprotection of 5a or 5b gave 9-[5,6-dideoxy-6-(p-toluenesulfonyl)-β-D-ribo-hexofuranosyl]adenine (6b). Isomerization of the vinyl tosyl (5b) to a 4′,5′-unsaturated allylic tosyl derivative (7) occurred under cleavage conditions and in solutions of aqueous or organic bases. Key words: adenosine, 5′-deoxyadenosine, 5′-methylene-5′-deoxyadenosine, nucleosides.

Nucleic acid related compounds. 78. Stereocontrolled syntheses of 6′(E and Z)-halovinyl analogues from uridine-derived vinylsulfones via vinyltin intermediates

1993 ◽  
Vol 71 (2) ◽  
pp. 192-198 ◽  
Author(s):  
Stanislaw F. Wnuk ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Trifluoroacetic Acid ◽  
Bond Cleavage ◽  
Lead Tetraacetate ◽  
Acetylenic Derivative ◽  
Vinyl Derivative ◽  
High Yields ◽  
Related Compounds

Treatment of the 6′(E)-tosylvinyl homonucleoside 1a with Bu3SnH/AIBN/toluene/Δ gave separable mixtures of 6′-vinylstannanes 2a(E/Z) in high yields. Stereospecific halodestannylations with N-iodosuccinimide, bromine, and N-bromosuccinimide proceeded smoothly to give the 6′(E or Z)-iodo(and bromo) vinyl compounds with retention of configuration. Chlorine or iodobenzene dichloride effected moderately stereoselective chlorodestannylation. Treatment of 2a with NH4F/MeOH/Δ resulted in carbon–tin bond cleavage to give the free vinyl derivative 4a. Aqueous trifluoroacetic acid effected concomitant protiodestannylation and deprotection of 2a to give 4b. Treatment of 2a(E) with lead tetraacetate/acetonitrile and deprotection afforded acetylenic derivative 3b.

Nucleic acid related compounds. 38. Smooth and high-yield iodination and chlorination at C-5 of uracil bases and p-toluyl-protected nucleosides

1982 ◽  
Vol 60 (5) ◽  
pp. 554-557 ◽  
Author(s):  
Morris J. Robins ◽  
Philip J. Barr ◽  
Jerzy Giziewicz
Keyword(s):  
Nucleic Acid ◽  
Organic Solvents ◽  
High Yield ◽  
Iodine Monochloride ◽  
High Yields ◽  
Related Compounds

Treatment of uracil bases and protected nucleosides with iodine monochloride (ICl) gave the corresponding 5-iodouracil products in over 95% purified yields. Analogously facile chlorination was effected with iodobenzene dichloride (PhICl2). Protection of the nucleosides as p-toluyl esters provided reactants that were soluble in organic solvents and crystallized readily in high yields.

Nucleic acid related compounds. 57. Synthesis, x-ray crystal structure, lipophilic partition properties, and antiretroviral activities of anomeric 3'-azido-2',3'-dideoxy-2,6-diaminopurine ribosides

1989 ◽  
Vol 32 (8) ◽  
pp. 1763-1768 ◽  
Author(s):  
Morris J. Robins ◽  
Steven G. Wood ◽  
N. Kent Dalley ◽  
Piet Herdewijn ◽  
Jan Balzarini ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nucleic Acid ◽  
X Ray ◽  
Related Compounds

Nickel-catalyzed multicomponent coupling reaction using ynones

2010 ◽  
Vol 82 (7) ◽  
pp. 1485-1490 ◽  
Author(s):  
Takayoshi Arai ◽  
Yui Ikematsu ◽  
Yuuki Suemitsu
Keyword(s):  
Carbonyl Group ◽  
Coupling Reaction ◽  
Conjugate Addition ◽  
Subsequent Treatment ◽  
Crystallographic Analysis ◽  
Coupling Reactions ◽  
X Ray ◽  
Tetrasubstituted Olefins ◽  
High Yields ◽  
Multicomponent Coupling

Conjugate addition of Me3SiCN to ynones is smoothly catalyzed by Ni(cod)2 to give β-cyano-silyloxyallenes quantitatively. Subsequent treatment of the silyloxyallenes with N-bromo succinimide (NBS) provides the tetrasubstituted α-bromo-β-cyanoenones in high yields (up to 95 %) with excellent Z-selectivity (E/Z = up to >1/99). X-ray crystallographic analysis shows a bent structure of the α-bromo-β-cyanoenone due to deconjugation of the π-bond and the carbonyl group. Furthermore, three-component coupling reactions of ynones, dialkylzinc, and alde-hydes are catalyzed by Ni(cod)2 to provide tetrasubstituted olefins.

Nucleic Acid Related Compounds. 136. Synthesis of 2-Amino- and 2,6-Diaminopurine Derivatives via Inverse-Electron-Demand Diels-Alder Reactions

2006 ◽  
Vol 71 (7) ◽  
pp. 1029-1041 ◽  
Author(s):  
Xiaoyu Lin ◽  
Morris J. Robins
Keyword(s):  
Nucleic Acid ◽  
Diels Alder ◽  
Curtius Rearrangement ◽  
X Ray ◽  
Inverse Electron Demand ◽  
X Ray Crystallography ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
Electron Demand

Thermal inverse-electron-demand Diels-Alder reactions of 5-aminoimidazoles and 2,4,6-tris(ethoxycarbonyl)-1,3,5-triazine (2) with spontaneous retro-Diels-Alder loss of ethyl cyanoformate and elimination of ammonia give 2,6-bis(ethoxycarbonyl)purines. A report that selective alkaline hydrolysis followed by acid-catalyzed decarboxylation gave 6-(ethoxycarbonyl)purine products was not in harmony with known reactions in purine chemistry. Our reinvestigation has shown that the 6-(ethoxycarbonyl) group undergoes preferential base-promoted hydrolysis, as expected, but regioselectivity for attack of hydroxide at the carbonyl group at C6 is not high (relative to hydrolysis of both C2 and C6 esters). The structure of 9-benzyl-2-(ethoxycarbonyl)purine was determined by X-ray crystallography and confirmed by Curtius rearrangement of the azidocarbonyl analogue to give 2-amino-6-benzylpurine. Acid-catalyzed decarboxylation of the 2,6-dicarboxylate formed during hydrolysis gave 9-benzylpurine, and Curtius rearrangement of 2,6-bis(azidocarbonyl)-9-benzylpurine gave 2,6-diamino-9-benzylpurine. Attempted applications of inverse-electron-demand Diels-Alder reactions of 2 with nucleoside derivatives were problematic.

scholarly journals Reactions of Carbonyl Compounds in Basic Solutions. Part 351: The Alkaline Hydrolysis and Reactivity – Structure – Spectra Correlations of (Z)-4-(Substituted Benzylidene)-2-Phenyl-4H-Oxazol-5-Ones

2002 ◽  
Vol 2002 (7) ◽  
pp. 309-310 ◽  
Author(s):  
Keith Bowden ◽  
Alexander Perjéssy ◽  
Ján Benko ◽  
Walter M. F. Fabian ◽  
Erkki Kolehmainen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Nmr Spectroscopy ◽  
Alkaline Hydrolysis ◽  
Carbonyl Compounds ◽  
Theoretical Calculations ◽  
X Ray ◽  
Basic Solutions ◽  
Kinetics Of ◽  
Related Compounds

The kinetics of the alkaline hydrolysis and the configuration, conformation and electronic structure were studied using IR, NMR spectroscopy, X-ray analysis and AM1 theoretical calculations for a series of (Z)-4-(substituted benzylidene)-2-phenyl-4H-oxazol-5-ones (1) and compared with analogous results reported for (E)-4-benzylidene-2-phenyl-4H-furan-5-ones (5) and related compounds.

Nucleic Acid Related Compounds. 14. 3′-O-Aminoacyl-2′-O-methyladenosines and 2′-O-Aminoacyl-3′-O-methyladenosines Related to Charged tRNA Termini

1974 ◽  
Vol 52 (22) ◽  
pp. 3803-3813 ◽  
Author(s):  
Morris J. Robins ◽  
Malcolm MacCoss ◽  
G. Ramani
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nucleic Acid ◽  
Protein Biosynthesis ◽  
Glycosidic Bonds ◽  
Acid Anhydrides ◽  
High Yields ◽  
First Time ◽  
Hydrolysis Of ◽  
Related Compounds

Aminoacyl nucleosides derived from 2′-O-methyladenosine and 3′-O-methyladenosine have been isolated as pure solids and completely characterized for the first time. Coupling of 5′-O-(mono-p-methoxytrityl)-2′-O-methyl- (and 3′-O-methyl-) adenosines (1 and 6, respectively) with N-tert-butyloxycarbonyl(N-tBOC)-amino acid anhydrides (2a–c) (generated insitu from the corresponding N-tBOC-amino acids and N,N′-dicyclohexylcarbodiimide) in the presence of 4-N,N-dimethylaminopyridine gave the 3′-O-(N-tBOC-aminoacyl)-5′-O-(mono-p-methoxytrityl-2′-O-methyladenosines (3a–c) and 2′-O-(N-tBOC-aminoacyl)-5′-O-(mono-p-methoxytrityl-3′-O-methyladenosines (7a–c), respectively, in good yields. The L-leucine (a), L-phenylalanine (b), and L-methionine (c) compounds were prepared in each series. Complete deblocking was effected using 98% formic acid since usual procedures had disadvantages with these molecules. The 3′-O-(L-aminoacyl)-2′-O-methyladenosines (4a–c) and 2′-O-(L-aminoacyl)-3′-O-methyladenosines (8a–c) were obtained in high yields with no detectable hydrolysis of the aminoacyl or glycosidic bonds under these conditions.N-Formylmethionyl and N-acetylphenylalanyl derivatives were prepared in each series by acylation of the deblocked products with acetic formic anhydride and p-nitrophenyl acetate, respectively. Biochemical rationale for the use of these compounds in the study of protein biosynthesis and initiation processes are discussed. The puromycin-like activity of 3′-O-phenylalanyl-2′-O-methyl-adenosine (4b) was confirmed.

Structures of Artificially Designed RNA Nanoarchitectures at Near-Atomic Resolution

2020 ◽  
Author(s):  
Di Liu ◽  
Yaming Shao ◽  
Joseph A. Piccirilli ◽  
Yossi Weizmann
Keyword(s):  
Nucleic Acid ◽  
High Resolution ◽  
Single Strand ◽  
Atomic Resolution ◽  
Rna Motifs ◽  
X Ray ◽  
Structural Details ◽  
Rna Motif

<p>Though advances in nanotechnology have enabled the construction of synthetic nucleic acid based nanoarchitectures with ever-increasing complexity for various applications, high-resolution structures are lacking due to the difficulty of obtaining good diffracting crystals. Here we report the design of RNA nanostructures based on homooligomerizable tiles from an RNA single-strand for X-ray determination. Three structures are solved to near-atomic resolution: a 2D parallelogram, an unexpectedly formed 3D nanobracelet, and a 3D nanocage. Structural details of their constituent motifs—such as kissing loops, branched kissing-loops and T-junctions—that resemble natural RNA motifs and resisted X-ray determination are revealed. This work unveils the largely unexplored potential of crystallography in gaining high-resolution feedback for nanostructure design and suggests a novel route to investigate RNA motif structures by configuring them into nanoarchitectures.</p>

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