Tetranortriterpenoids and related compounds. Part 25. Two 3,4-secotirucallane derivatives and 2′-hydroxyrohitukin from the bark of Guareacedrata (Meliaceae)

1980 ◽  
Vol 58 (17) ◽  
pp. 1865-1868 ◽  
Author(s):  
John A. Akinniyi ◽  
Joseph D. Connolly ◽  
David S. Rycroft ◽  
B. Lucas Sondengam ◽  
N. Patience Ifeadike
Keyword(s):  
Dioic Acid ◽  
Nmr Data ◽  
New Compounds ◽  
Related Compounds ◽  
Monomethyl Ester ◽  
C Nmr

Three new compounds, 3,4-secotirucalla-4(28),7,24-trien-3,21-dioic acid 1, the corresponding 3-monomethyl ester 12, and 2′-hydroxyrohitukin 13, have been isolated from the bark of Guareacedrata (Meliaceae). The structures of 1 and 12 were confirmed by correlation with methyl 3-oxotirucalla-8,24-dien-21-oate (methyl isoelemonate) 6. The 1H and 13C nmr data are reported.

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 Synthesis of Some Novel Fused Imidazo [2, 1-b] [1, 3] Thiazole and Imidazo [2, 1-b] Thiazolo [5, 4-d] Isoxazole Derivatives

2012 ◽  
Vol 9 (3) ◽  
pp. 1518-1525 ◽  
Author(s):  
Hamid Reza Jaberi ◽  
Hadi Noorizadeh
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Carbon Disulphide ◽  
Thiazole Derivatives ◽  
H Nmr ◽  
Nmr Data ◽  
Elemental Analyses ◽  
New Compounds ◽  
Isoxazole Derivatives ◽  
C Nmr

In this work we describe the synthesis of some novel fused imidazo [2, 1-b] [1, 3] thiazole derivatives. The reaction of 1, 2-diaminoethane 1 with carbon disulphide in H2O/ETOH as solvent furnishes 4, 5-dihydro-1H-imidazol-2-thiol 2 under reflux condition. the reaction of 4,5-dihydro-1H-imidazol-2-thiol on treatment with ethylchloro acetate and aromatic aldehyde in presence of anhydrous sodium acetate and acetic acid as solvent to give (Z)-2-(arylidene)-5,6-dihydroimidazo [2,1-b] [1,3] thiazol-3(2H)-one 3a-j. Compounds 3a-j was condensed with hydroxylamine to give 3-(aryl)-2, 3, 6, 7-tetrahydroimidazo [2, 1-b] [1,3] thiazolo [5, 4-d] isoxazole 4a-j. The structures of the new compounds were established by elemental analyses, IR,1H NMR and13C NMR data.

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.

Chemistry of the shellfish toxin domoic acid: characterization of related compounds

1994 ◽  
Vol 72 (2) ◽  
pp. 430-436 ◽  
Author(s):  
John A. Walter ◽  
Michael Falk ◽  
Jeffrey L.C. Wright
Keyword(s):  
Molecular Modelling ◽  
Domoic Acid ◽  
Conformational Flexibility ◽  
Spectroscopic Methods ◽  
Clear Cut ◽  
Nmr Data ◽  
Shellfish Toxin ◽  
New Compounds ◽  
Related Compounds

Five new compounds related to the neurotoxin domoic acid have been characterized by spectroscopic methods. They include a diastereoisomer that occurs naturally with domoic acid in mussels and four hydrogenation products. The stereochemistry of the two epimeric tetrahydro derivatives could not be assigned on the basis of the NMR data alone because of high conformational flexibility. However, a clear-cut assignment was possible by molecular modelling in combination with the NMR data.

Organoborierung von Alkinylstannanen, VIII [1] Zur Reaktion von Alkinyltrimethylstannanen mit 1-Boracyclopentanen und Methylbis(tert-butyl)boran / Organoboration of Alkynylstannanes, VIII [1] The Reaction of Alkynyltrimethylstannanes with 1-Boracyclopentanes and Methy Ibis (tert-butyl) borane

1978 ◽  
Vol 33 (8) ◽  
pp. 855-861 ◽  
Author(s):  
Axel Schmidt ◽  
Bernd Wrackmeyer
Keyword(s):  
Analogous Reaction ◽  
Tert Butyl ◽  
Nmr Data ◽  
New Compounds ◽  
C Nmr

Abstract 1-Organyl-1-boracyclopentanes react with alkynyltrimethylstannanes to give 1-bora-cyclohexylid(2)enes as the only products. The analogous reaction with methylbis (tert-butyl)borane leads to a nonstatistical distribution of organoboration products. Structure and stereochemistry of the new compounds are discussed on the basis of methanolysis reactions and 1H, 11B and 13C NMR data.

Vom "criss-cross"-Schema abweichende Cycloadditionsreaktionen an das Azin-System [1] Zum Cycloadditionsverhalten von Hexafluoracetonazin gegenüber N.N-Dialkyl-cyanamiden [2] / Cycloaddition Reactions of Azines Violating the "criss-cross" Cycloaddition Scheme [1] Cycloaddition Behaviour of Hexafluoroacetone Azine towards N,N-Dialkyl-cyanamides [2]

1982 ◽  
Vol 37 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Klaus Burger ◽  
Friedrich Hein ◽  
Joachim Firl
Keyword(s):  
Molar Ratio ◽  
Addition Reactions ◽  
Cycloaddition Reactions ◽  
Reaction Conditions ◽  
Tert Butyl ◽  
Nmr Data ◽  
System 1 ◽  
New Compounds ◽  
C Nmr

Abstract Depending upon the molar ratio of the educts and the reaction conditions used, hexa-fluoroacetone azine (1) reacts with N,N-dialkyl-cyanamides (2) to give 3,4,6-triazaocta-2,4,6-trienes (6) and/or 4,4-bis(trifluoromethyl)-1,4-dihydro-1,3,5-triazines (7). Cyclo-addition reactions of 6 with tert-butyl isocyanide and 1-diethylamino(propine) are de-scribed. IR, 1H, 19F, and 13C NMR data of the new compounds are discussed.

Conversion of substituted 5-aryloxypyrazolecarbaldehydes into reduced 3,4′-bipyrazoles: synthesis and characterization, and the structures of four precursors and two products, and their supramolecular assembly in zero, one and two dimensions

2019 ◽  
Vol 75 (6) ◽  
pp. 768-776 ◽  
Author(s):  
Haruvegowda Kiran Kumar ◽  
Hemmige S. Yathirajan ◽  
Nagaraj Manju ◽  
Balakrishna Kalluraya ◽  
Ravindranath S. Rathore ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Supramolecular Assembly ◽  
Two Dimensions ◽  
Subsequent Reaction ◽  
Orientational Disorder ◽  
New Compounds ◽  
Cyclocondensation Reactions ◽  
Related Compounds ◽  
Centrosymmetric Dimers ◽  
C Nmr

The reaction of 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde with phenols under basic conditions yields the corresponding 5-aryloxy derivatives; the subsequent reaction of these carbaldehydes with substituted acetophenones yields the corresponding chalcones, which in turn undergo cyclocondensation reactions with hydrazine in the presence of acetic acid to form N-acetylated reduced bipyrazoles. Structures are reported for three 5-aryloxycarbaldehydes and the 5-piperidino analogue, and for two reduced bipyrazole products. 5-(2-Chlorophenoxy)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde, C17H13ClN2O2, (II), which crystallizes with Z′ = 2 in the space group P\overline{1}, exhibits orientational disorder of the carbaldehyde group in each of the two independent molecules. Each of 3-methyl-5-(4-nitrophenoxy)-1-phenyl-1H-pyrazole-4-carbaldehyde, C17H13N3O4, (IV), 3-methyl-5-(naphthalen-2-yloxy)-1-phenyl-1H-pyrazole-4-carbaldehyde, C21H16N2O2, (V), and 3-methyl-1-phenyl-5-(piperidin-1-yl)-1H-pyrazole-4-carbaldehyde, C16H19N3O, (VI), (3RS)-2-acetyl-5-(4-azidophenyl)-5′-(2-chlorophenoxy)-3′-methyl-1′-phenyl-3,4-dihydro-1′H,2H-[3,4′-bipyrazole] C27H22ClN7O2, (IX) and (3RS)-2-acetyl-5-(4-azidophenyl)-3′-methyl-5′-(naphthalen-2-yloxy)-1′-phenyl-3,4-dihydro-1′H,2H-[3,4′-bipyrazole] C31H25N7O2, (X), has Z′ = 1, and each is fully ordered. The new compounds have all been fully characterized by analysis, namely IR spectroscopy, 1H and 13C NMR spectroscopy, and mass spectrometry. In each of (II), (V) and (IX), the molecules are linked into ribbons, generated respectively by combinations of C—H...N, C—H...π and C—Cl...π interactions in (II), C—H...O and C—H...π hydrogen bonds in (V), and C—H...N and C—H...O hydrogen bonds in (IX). The molecules of compounds (IV) and (IX) are both linked into sheets, by multiple C—H...O and C—H...π hydrogen bonds in (IV), and by two C—H...π hydrogen bonds in (IX). A single C—H...N hydrogen bond links the molecules of (X) into centrosymmetric dimers. Comparisons are made with the structures of some related compounds.

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.

Unexpected Keto-enol Tautomerism in the Cyclopyridinophane Class Direct and indirect proofs

2008 ◽  
Vol 59 (10) ◽  
Author(s):  
Paul Ionut Dron ◽  
Neculai Doru Miron ◽  
Gheorghe Surpateanu
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Stable Conformer ◽  
Ph Measurements ◽  
Theoretical Methods ◽  
Nmr Data ◽  
Tautomeric Forms ◽  
New Compounds

The paper presents the synthesis of cyclo (bis-paraquat p-phenylene p-phenylene-carbonyl) tetrakis (hexafluorophosphate), named �CETOBOX�, and the closely related structural determinations. This compound exists in three tautomeric forms. These forms were evidentiated by NMR-data (1H-NMR, TOCSY, COSY, NOESY), UV-Vis spectra coupled with pH measurements and by synthesis. As the �CETOBOX� gives �in situ� only the corresponding monoylide, the synthesis of a new fluorescent indolizine cyclophane has been performed by a 3+2 cycloaddition. All structures of the new compounds presented herein have been established by NMR spectroscopy. Also, theoretical methods (MM3, AM1, AM1-COSMO and B88LYPDFT) have been used to determine the most stable conformer structures.

Glucan isolated from leaves of Althaea officinalis L.

1983 ◽  
Vol 48 (7) ◽  
pp. 2082-2087 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Jozef Rosík ◽  
Rudolf Toman ◽  
Peter Capek
Keyword(s):  
Medicinal Plant ◽  
Periodate Oxidation ◽  
Linear Structure ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Methylation Analysis ◽  
Glycosidic Bonds ◽  
Nmr Data ◽  
Althaea Officinalis ◽  
C Nmr

A water-soluble low-molecular D-glucan was isolated from leaves of the medicinal plant marsh-mallow (Althaea officinalis L.). The results of methylation analysis, partial hydrolysis, periodate oxidation, and 13C NMR data indicated a virtually linear structure with α-(1→6) glycosidic bonds.

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