Nucleic acid related compounds. 36. Synthesis of the 2′-O-methyl and 3′-O-methyl ethers of guanosine and 2-aminoadenosine and correlation of O′-methylnucleoside 13C nmr spectral shifts

1981 ◽  
Vol 59 (24) ◽  
pp. 3360-3364 ◽  
Author(s):  
Morris J. Robins ◽  
Fritz Hansske ◽  
Salwa E. Bernier
Keyword(s):  
Nucleic Acid ◽  
13C Nmr ◽  
Chloride Dihydrate ◽  
Spectral Shifts ◽  
Nmr Data ◽  
Related Compounds ◽  
In Situ Replacement ◽  
Isomeric Methyl ◽  
C Nmr

A modified trimethylsilylation of guanosine (1) followed by in situ replacement of the 6-trimethylsilyloxy group with ammonia at 150 °C gave 2,6-diamino-9-β-D-ribofuranosylpurine (2) in 92% yield. Treatment of 2 with diazomethane in the presence of tin(II) chloride dihydrate gave the 2′-O-methyl (3) and 3′-O-methyl (4) ethers of 2 in 98% combined yield. The ratios of 3/4 could be varied from 51:47 to 34:64 by changing the amount of catalyst used. Treatment of 3 and 4 with adenosine deaminase resulted in clean conversion of these 2-aminoadenosine ethers to 2′-O-methylguanosine (5) and 3′-O-methylguanosine (6), respectively, in optimized yields of 40% and 54% overall from 1. The 13C nmr data for six ribonucleosides and their isomeric methyl ether derivatives have been correlated to provide a convenient method of identification.

scholarly journals Structural Investigations of C-Nitrosobenzenes. Part 3.1 Solid-state and Solution 13C NMR Studies, and Crystal Structure of E-(4-CIC6H4NO)2

1999 ◽  
Vol 23 (3) ◽  
pp. 202-203
Author(s):  
Daniel A. Fletcher ◽  
Brian G. Gowenlock ◽  
Keith G. Orrell ◽  
David C. Apperley ◽  
Michael B. Hursthouse ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
13C Nmr ◽  
Nmr Studies ◽  
Structural Investigations ◽  
Nmr Data ◽  
C Nmr

Solid-state and solution 13C NMR data for the monomers and dimers of 3- and 4-substituted nitrosobenzenes, and the crystal structure of E-(4-CIC6H4NO)2 are reported.

1-Carba-arachno-pentaborane(10) Derivatives

1997 ◽  
Vol 62 (8) ◽  
pp. 1254-1262 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Hans-Jörg Schanz
Keyword(s):  
High Yield ◽  
Exchange Reactions ◽  
Nmr Data ◽  
Substituted 1 ◽  
C Nmr

The formation of organo substituted 1-carba-arachno-pentaborane(10) derivatives is shown to proceed in high yield via in situ generated 1,1,1-tris(diethylboryl)propane (2) from diethyl(propyn-1-yl)borane (1) by hydroboration with an excess of diethylborane (hydride bath). In the hydride bath, exchange reactions between 2 and other geminal bis(diethylboryl)alkanes take place until the carbaborane skeleton is formed. If tris(diethylboryl)methane is used under the same conditions, the corresponding 1-carba-arachno-pentaborane(10) derivatives 11 and 12 are formed in mixture with other unknown boranes or carboranes. 11B and 13C NMR data are presented to allow for straightforward identification of the 1-carba-arachno-pentaboranes(10).

NMR-spektroskopische Untersuchungen an 1,1-Thiophendioxid und verwandten Verbindungen / NMR Spectroscopical Investigations of Thiophene 1,1-Dioxide and Related Compounds

1984 ◽  
Vol 39 (7) ◽  
pp. 915-920 ◽  
Author(s):  
Herbert Meier ◽  
Thomas Molz ◽  
Heinz Kolshorn
Keyword(s):  
Computer Simulation ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Multiple Resonance ◽  
Nmr Data ◽  
Cyclic Diene ◽  
Related Compounds ◽  
C Nmr

The 1H and 13C NMR data of thiophene 1,1-dioxide (3) and related compounds, especially of the precursor 2 and the consecutive product 5 are evaluated by computer simulation and multiple resonance. Chemical shifts and coupling constants reveal that 3 has the character of a cyclic diene. Diatropic or paratropic effects can be excluded.

scholarly journals The NMR Spin Systems of Scutellaria 8β,13-Epoxy-neo-clerod-3-en-15,16-olides and Revision of 1H and 13C NMR Spectra Reported Data

2020 ◽  
Vol 15 (10) ◽  
pp. 1934578X2093378
Author(s):  
Josep Coll Toledano
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Spin Systems ◽  
13C Nmr Spectra ◽  
1H And 13C Nmr ◽  
Nmr Data ◽  
Reported Data ◽  
New Compounds ◽  
C Nmr ◽  
Shielding Effects

The present review of NMR spectroscopic structural elucidation data of new compounds isolated from Scutellaria species is focused on the title compounds, displaying a peculiar 13-spiro feature. It contains a compilation of 1H and 13C NMR data of these diterpenoids grouped by similar substitution patterns. Comparing shielding effects pointed out not only the identity of some compounds (already reported) but also potential misassignments and convenient revisions to get unambiguous structural proposals.

scholarly journals Clerodane Diterpenes from Croton Species: Distribution and a Compilation of their 13C NMR Spectral Data

2006 ◽  
Vol 1 (4) ◽  
pp. 1934578X0600100 ◽  
Author(s):  
Sebastião F. Palmeira Jünior ◽  
Lucia M. Conserva ◽  
José Maria Barbosa Filho
Keyword(s):  
Spectral Data ◽  
Species Distribution ◽  
13C Nmr ◽  
Biological Activities ◽  
Review Of The Literature ◽  
Nmr Data ◽  
Clerodane Diterpenes ◽  
C Nmr

The present work is a review of the literature of clerodane diterpenes from Croton species. It contains a compilation of 13C NMR data of 83 of these diterpenoids and their biological activities. This review covers a period from 1969 to October 2005 and 224 references are cited.

Solution Structures of Pyrophthalones, I Structure and Conformation of 1,3-Indandionato-2(2-pyridinium)-betaïn — a 1H/13C NMR Approach

1987 ◽  
Vol 42 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Erhard T. K. Haupt ◽  
Heindirk tom Dieck ◽  
Panayot R. Bontchev
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Complete Analysis ◽  
Solution Structures ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Related Compounds ◽  
C Nmr

AbstractThe complete analysis of the 1H/13 C NMR spectra of α-Pyrophthalone and related compounds demonstrates that the earlier static planar description of the molecules is invalid for polar sol-vents, and here the stability of any intramolecular hydrogen bond is small.

scholarly journals Darstellung, 11B-, 13C-NMR- und Schwingungsspektren der closo-Hexaborate [B6H5(CN)12- und cis-[B6H4(CN)2]2− sowie Kristallstruktur von Cs2[B6H5(CN)] / Preparation, 11B,13C NMR and Vibrational Spectra of the closo-Hexaborates [B6H5(CN)]2- and cis-[B6H4(CN)2]2-, and the Crystal Structure of Cs2[B6H5(CN)]

1993 ◽  
Vol 48 (5) ◽  
pp. 598-602 ◽  
Author(s):  
W. Preetz ◽  
A. Franken ◽  
M. Rath
Keyword(s):  
Crystal Structure ◽  
13C Nmr ◽  
Exchange Chromatography ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
Diethylaminoethyl Cellulose ◽  
Ir And Raman ◽  
C Nmr

By reaction of Cs2[B6H6] with in situ generated dicyanogen in aqueous alkaline solution the monocyanohydrohexaborate Cs2[B6H5(CN)] and the dicyanohydrohexaborate cis-Cs2[B6H4(CN)2] are formed. The compounds have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of Cs2[B6H5(CN)] was determined from single crystal X-ray diffraction analysis; monoclinic, space group P21/a with a = 9.540(8), b = 9.977(3), c = 10.578(2)Å, β = 105.06(2)°. The B6 octahedron is compressed in the direction of the nearly linear B—CN bond by about 5%, with bond lengths between 1.71 and 1.76Å. The "B NMR spectra of the two compounds reveal the features of substituted B6 cages with C4v and C2v point symmetry. In the 13C NMR spectrum of Cs2[B6H5(CN)] a quartet at -139 ppm with 1J(C,B) 92 Hz is observed. The IR and Raman spectra exhibit very strong CN stretching bands for Cs2[B6H5(CN)] at 2149, and for cis-Cs2[B6H4(CN)2] at 2170 cm-1.

13C-NMR chemische Verschiebung phenylsubstituierter polycyclischer Kohlenwasserstoffe / 13C-NMR Chemical Shift of Phenylsubstituted Polycyclic Hydrocarbons

1979 ◽  
Vol 34 (11) ◽  
pp. 1334-1343 ◽  
Author(s):  
W. Storek ◽  
J. Sauer ◽  
R. Stößer
Keyword(s):  
Chemical Shift ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Ring Current ◽  
Current Effect ◽  
Nmr Data ◽  
Ring Current Effect ◽  
Anisotropic Contribution ◽  
Chemische Verschiebung ◽  
C Nmr

13C-NMR spectra of tetracene, rubrene, 1,3,5-tri-, penta-, and hexaphenylbenzene are reported. The discussion also includes the already known 13C-NMR data for diphenyl, 9,10-diphenyl-, 9,10-dibenzyl-, and 9,10-dimethyl-anthracene [1] as well as toluene. On the basis of CNDO/2 calculations different influences (diamagnetic and paramagnetic term, anisotropic contribution, ring current effect, geometry) on the chemical shift are analyzed for diphenyl and within the row benzene through tetracene

Nucleic acid related compounds. 35. Synthesis of 5-bromo- and 5-deuterio-3-deazauridine

1981 ◽  
Vol 59 (24) ◽  
pp. 3356-3359 ◽  
Author(s):  
Morris J. Robins ◽  
Chisato Kaneko ◽  
Masakatsu Kaneko
Keyword(s):  
Nucleic Acid ◽  
Anticancer Agent ◽  
Clinical Implications ◽  
Catalytic Hydrogenolysis ◽  
Related Compounds

Bromination of 3-deazauracil (4-hydroxy-2-pyridinone) (1) gave the 3,5-dibromo compound (2). Selective debromination of 2 gave 5-bromo-4-hydroxy-2-pyridinone (3). Trimethylsilylation of 3 and condensation of the product (4) in situ with tetra-O-acetyl-β-D-ribofuranose (5) using tin(IV) chloride as catalyst gave 1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-5-bromo-4-hydroxy-2-pyridinone (7). Deprotection of 7 gave 5-bromo-3-deazauridine (6). Catalytic hydrogenolysis of 7 gave 3-deazauridine triacetate (8a) and deuteriolysis gave the 5-deuterio product (8b). Deprotection of 8b gave the isotope-labeled anticancer agent, 5-deuterio-3-deazauridine (9). Biochemical and clinical implications are discussed.

11B- und 13C-NMR-Spektroskopie von nido-Hexaalkyl-2.3.4.5-tetracarbahexaboranen(6) / 11B- und 13C-NMR Spectroscopy of nido-Hexaalkyl-2,3,4,5-tetracarbahexaboranes(6)

1982 ◽  
Vol 37 (4) ◽  
pp. 412-419 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Coupling Constants ◽  
Triple Resonance ◽  
Triple Resonance Experiments ◽  
Nmr Data ◽  
Nuclear Shielding ◽  
C Nmr

11B and 13C NMR data of peralkylated nido-2,3,4,5-tetracarbahexaboranes(6) are reported. Application of selective heteronuclear triple resonance experiments 13C{1H,11B} enables to assign the structures of various isomers. The magnitude of the coupling constants 1J(11B11B), 1J(13C11B) and 1J(13C13C) is in accord with expectations based on the conception of bonding in carboranes. The comparison of δ11B and δ13C data of the nido- 2,3,4,5-tetracarboranes(6) with δ13C-data of corresponding non-classical carbocations shows the influence of charge upon the nuclear shielding of carbon in the latter.

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