SOME STRUCTURAL FEATURES OF DELCOSINE

1958 ◽  
Vol 36 (5) ◽  
pp. 766-770 ◽  
Author(s):  
Ragini Anet ◽  
Léo Marion
Keyword(s):  
Heterocyclic Ring ◽  
Structural Features ◽  
Membered Ring ◽  
Hydroxyl Groups ◽  
Supporting Evidence ◽  
Methylene Group ◽  
Tertiary Hydroxyl

The alkaloid delcosine has previously been assigned tentatively the same carbon–nitrogen skeleton as lycoctonine to which it appears to be closely related in properties. Oxidation experiments now reported provide supporting evidence of the presence of two vicinal tertiary hydroxyl groups attached to a five- and a six-membered ring that are directly linked together at the two carbons carrying the hydroxyls. There is a methoxyl in a position β to the tertiary hydroxyl of the six-membered ring. Evidence is also provided as to the size of the heterocyclic ring and the presence of a methylene group next to the nitrogen.

CHASMANINE AND ITS STRUCTURE

1965 ◽  
Vol 43 (4) ◽  
pp. 825-839 ◽  
Author(s):  
O. Achmatowicz Jr. ◽  
Y. Tsuda ◽  
Léo Marion ◽  
T. Okamoto ◽  
Mitsutaka Natsume ◽  
...  
Keyword(s):  
Cyclic Ether ◽  
Membered Ring ◽  
Hydroxyl Groups ◽  
Lithium Aluminium Hydride ◽  
Allylic Rearrangement ◽  
Rearrangement Product ◽  
Lithium Aluminium ◽  
Pyrolytic Reaction ◽  
Acid Catalyzed ◽  
Tertiary Hydroxyl

The alkaloid chasmanine, C25H41O6N, isolated from A. chasmanthum contains four methoxyl and two hydroxyl groups as well as an imino-ethyl. It undergoes the usual pyrolytic reaction and the unsaturated product, pyrochasmanine, C25H39O5N, gives rise to an acid-catalyzed allylic rearrangement product, isopyrochasmanine. Pyrochasmanine, on treatment with lithium aluminium hydride, is demethoxylated. It can be concluded that the base, like bikhaconine, contains the sequence [Formula: see text]. Chasmanine can be oxidized to a compound containing a cyclopentanone ring so that its second hydroxyl must be secondary and located on a five-membered ring. It is possible to benzoylate the secondary hydroxyl and acetylate the tertiary hydroxyl. The n.m.r. characteristics of the resulting double ester determine the location of these two groups and their stereochemistry. The relative position of two of the remaining methoxyl groups is established via a demethylation reaction resulting in the formation of a cyclic ether. All the chemical reactions studied are in agreement with structure IV (R = R′ = H) for chasmanine. There is, however, no positive proof for the location of the fourth methoxyl and it has been placed in ring A by analogy. An attempted correlation with bikhaconine is described.

EHT study of reactivity of methylene group in 1-methyl-1,4-dihydronicotinamide

1980 ◽  
Vol 45 (9) ◽  
pp. 2425-2432
Author(s):  
Jiří Krechl ◽  
Josef Kuthan
Keyword(s):  
Heterocyclic Ring ◽  
Covalent Bonds ◽  
Electronic Mechanism ◽  
Methylene Group ◽  
Plane Form ◽  
Reaction Profile

It has been demonstrated that the EHT method predicts an almost plane form of the heterocyclic ring in 1-methyl-1,4-dihydronicotinamide I (R = CH3) and also reflects satisfactorily character of the covalent bonds in the 4-methylene group. An attempt has been made of calculation of the reaction profile of elimination of the centre 4', and electronic mechanism of its splitting off is discussed.

Bisquaternary ammonium salts derived from 3α,12α-Diamino-5β-cholane and 3α,12α-Diamino-24-nor-5β-cholane

1971 ◽  
Vol 24 (3) ◽  
pp. 521 ◽  
Author(s):  
S Ahmed ◽  
M Alauddin ◽  
B Caddy ◽  
M Martin-Smith ◽  
WTL Sidwell ◽  
...  
Keyword(s):  
Deoxycholic Acid ◽  
Ammonium Salts ◽  
Hydroxyl Group ◽  
Amino Compound ◽  
Hydroxyl Groups ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Polyhydric Alcohols ◽  
Methane Sulphonate ◽  
Methylene Group

The preparation of 3α,12α-bisdimethylamino-5β-cholane dimethiodide, 3α,12α-bisdimethylamino-5β-cholane dimethiodide, 3α,12α- bisdimethylamino-24-nor-5β-cholanedimethiodide, and 3α,12α- bisdimethylamino-24-nor-5β-cholanediethiodide, from deoxycholic acid are described. During this work it was found that attempted copper- quinoline decarboxylation of dehydrocholic acid gives rise to lactol formation, and that what had previously been considered to be 3α,12α- dihydroxy-5β-cholane is a mixture of this compound and 12α,24- dihydroxy-5β-cholane. Comparable selectivity of attack by methanesulphonyl chloride and toluene-p-sulphonyl chloride occurs with various polyhydric alcohols derived from bile acids, as evidenced from the products of reduction of the sulphonates with lithium aluminium hydride. With both 5α- and 5β-cholane derivatives, a C 3 equatorial hydroxyl group exhibits comparable reactivity to the terminal primary hydroxyl group, generated from the bile acid carboxylic group, towards both sulphonyl chlorides. With axial hydroxyl groups at C 7 and C 12, toluene-p-sulphonate formation is much more difficult than methane- sulphonate formation. Reduction by means of lithium aluminium hydride of equatorial sulphonate esters at C 7 and C 12 gives rise to a methylene group, but the axial sulphonates under the same conditions give the axial alcohol. The same clear distinction between equatorial and axial sulphonate esters is not observed at C 3 and C 6, but 17α- methanesulphonyloxy-5α-androstane gives 5α-androstane and the 17β- ester gives 17β-hydroxy-5α-androstane. Reduction of 12-oximino groups in both 5α- and 5β-cholanes with sodium and ethanol, hydrogen in the presence of a catalyst, or lithium aluminium hydride gives solely the 12α-amino compound.

SYNTHESIS OF METHYL 4-ACETAMIDO-4-DEOXY-L-ERYTHROFURANOSIDE: A SUGAR WITH NITROGEN IN A FIVE-MEMBERED RING

1964 ◽  
Vol 42 (1) ◽  
pp. 20-24 ◽  
Author(s):  
W. A. Szarek ◽  
J. K. N. Jones
Keyword(s):  
Structural Features ◽  
Membered Ring

The synthesis of methyl 4-acetamido-4-deoxy-L-erythrofuranoside from D-ribose is described. The structural features that are believed to be necessary for the replacement of the ring oxygen of sugars by nitrogen are discussed.

THE REACTION OF DIETHYL AZODICARBOXYLATE WITH DIHYDROGELSEMINE

1955 ◽  
Vol 33 (4) ◽  
pp. 604-609 ◽  
Author(s):  
Thelma Habgood ◽  
Léo Marion
Keyword(s):  
Infrared Spectrum ◽  
Methyl Ether ◽  
Sodium Borohydride ◽  
Lithium Aluminum Hydride ◽  
Chromic Acid ◽  
Aluminum Hydride ◽  
Membered Ring ◽  
Lithium Aluminum ◽  
Diethyl Azodicarboxylate ◽  
Methylene Group

Dihydrogelsemine reacts with diethyl azodicarboxylate yielding a carbinolamine which forms a methyl ether. Both this ether and the carbinolamine base can be oxidized by chromic acid to the same neutral lactam. That there has been no rearrangement of the carbon skeleton during these reactions is shown by reduction of the methyl ether of the carbinolamine with sodium borohydride to dihydrogelsemine and by reduction of the lactam with lithium aluminum hydride to tetrahydrodesoxygelsemine. It is concluded that both dihydrogelsemine and gelsemine contain a methylene group adjacent to N(b), and from the infrared spectrum of the lactam of dihydrogelsemine, N(b) appears to be part of a five-membered ring.

scholarly journals Characterization of Ionic Liquid Lignins Isolated from Spruce Wood with 1-Butyl-3-methylimidazolium Acetate and Methyl Sulfate and Their Binary Mixtures with DMSO

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2479 ◽  
Author(s):  
Artyom V. Belesov ◽  
Anton V. Ladesov ◽  
Ilya I. Pikovskoi ◽  
Anna V. Faleva ◽  
Dmitry S. Kosyakov
Keyword(s):  
Ionic Liquids ◽  
Binary Mixtures ◽  
Plant Biomass ◽  
High Resolution Mass Spectrometry ◽  
Covalent Binding ◽  
Structural Features ◽  
Size Exclusion ◽  
Hydroxyl Groups ◽  
Spruce Wood

Ionic liquids (ILs) based on 1-butyl-3-methylimidazolium (bmim) cation have proved to be promising solvents for the fractionation of plant biomass with the production of cellulose and lignin. This study deals with the characterization of lignins isolated from coniferous (spruce) wood using [bmim]OAc and [bmim]MeSO4 ionic liquids and their binary mixtures with DMSO (80:20). Molecular weight distributions, functional composition, and structural features of IL lignins were studied by size-exclusion chromatography, NMR spectroscopy (1D and 2D) and atmospheric pressure photoionization high-resolution mass spectrometry. It was shown that the interaction of ILs with lignin leads to significant chemical changes in the biopolymer; a decrease in the degree of polymerization and in the content of free phenolic hydroxyl groups due to alkylation, the disappearance (in the case of [bmim]OAc) of carbonyl groups and a significant destruction of β-O-4 bonds. The chemical reactions between lignin and 1-butyl-3-methylidazolium cation with covalent binding of ionic liquids or products of their decomposition is evidenced by the presence of a large number of nitrogen-containing oligomers in IL lignins.

scholarly journals On the nature of the electronic effect of multiple hydroxyl groups in the 6-membered ring – the effects are additive but steric hindrance plays a role too

2017 ◽  
Vol 15 (5) ◽  
pp. 1164-1173 ◽  
Author(s):  
Christian Marcus Pedersen ◽  
Mikael Bols
Keyword(s):  
Steric Hindrance ◽  
Electronic Effect ◽  
Membered Ring ◽  
Steric Effects ◽  
Hydroxyl Groups ◽  
Base Strength ◽  
Electronic And Steric Effects

Electronic and steric effects each play important roles in determining the base strength in piperidines.

scholarly journals Antioxidant Activity of Selected Phenolic Acids–Ferric Reducing Antioxidant Power Assay and QSAR Analysis of the Structural Features

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3088
Author(s):  
Maciej Spiegel ◽  
Karina Kapusta ◽  
Wojciech Kołodziejczyk ◽  
Julia Saloni ◽  
Beata Żbikowska ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Acids ◽  
Density Functional ◽  
Multiple Linear Regression Model ◽  
Structural Features ◽  
Hydroxyl Groups ◽  
Antioxidant Power ◽  
Qsar Analysis ◽  
Structure Activity ◽  
Ferric Reducing Antioxidant Power

Phenolic acids are naturally occurring compounds that are known for their antioxidant and antiradical activity. We present experimental and theoretical studies on the antioxidant potential of the set of 22 phenolic acids with different models of hydroxylation and methoxylation of aromatic rings. Ferric reducing antioxidant power assay was used to evaluate this property. 2,3-dihydroxybenzoic acid was found to be the strongest antioxidant, while mono hydroxylated and methoxylated structures had the lowest activities. A comprehensive structure–activity investigation with density functional theory methods elucidated the influence of compounds topology, resonance stabilization, and intramolecular hydrogen bonding on the exhibited activity. The key factor was found to be a presence of two or more hydroxyl groups being located in ortho or para position to each other. Finally, the quantitative structure–activity relationship approach was used to build a multiple linear regression model describing the dependence of antioxidant activity on structure of compounds, using features exclusively related to their topology. Coefficients of determination for training set and for the test set equaled 0.9918 and 0.9993 respectively, and Q2 value for leave-one-out was 0.9716. In addition, the presented model was used to predict activities of phenolic acids that haven’t been tested here experimentally.

REACTIONS OF OXODELCOSINE AND INTERRELATION OF DELCOSINE AND DELSOLINE

1960 ◽  
Vol 38 (12) ◽  
pp. 2433-2440 ◽  
Author(s):  
Vinko Skarić ◽  
Léo Marion
Keyword(s):  
Sodium Borohydride ◽  
Membered Ring ◽  
Lead Tetraacetate ◽  
The Other ◽  
Supporting Evidence ◽  
Close Relationship ◽  
Suggested Structure ◽  
Hydrolysis Of

The oxidation of diacetyldelcosine produces a lactam which, after hydrolysis of the acetyl groups, can be oxidized further to a diketo-lactam in which one of the keto groups is in a five- and the other in a six-membered ring. This result leads to an alteration of the previously suggested structure of delcosine. The new structure suggests a close relationship between delcosine and delsoline which is confirmed by the methylation of the former. The reaction is selective and gives rise to a monomethyldelcosine identical in every way with delsoline. Reduction of the diketo-lactam (didehydro-oxodelcosine) with sodium borohydride gives oxodelcosine. Dehydro-oxodelcosine is also described, and its oxidation with lead tetraacetate as well as that of oxodelcosine lead to the formation of keto-products which lend supporting evidence for the structure assigned to delcosine.

scholarly journals Structural insights into the specific anti-HIV property of actinohivin: structure of its complex with the α(1–2)mannobiose moiety of gp120

2012 ◽  
Vol 68 (12) ◽  
pp. 1671-1679 ◽  
Author(s):  
M. Mominul Hoque ◽  
Kaoru Suzuki ◽  
Masaru Tsunoda ◽  
Jiandong Jiang ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Open Space ◽  
Tandem Repeats ◽  
Specific Binding ◽  
Structural Features ◽  
Hydroxyl Groups ◽  
Mannose Residue ◽  
Specific Affinity ◽  
Anti Hiv ◽  
Hiv 1

Actinohivin (AH) is an actinomycete lectin with a potent specific anti-HIV activity. In order to clarify the structural evidence for its specific binding to the α(1–2)mannobiose (MB) moiety of the D1 chains of high-mannose-type glycans (HMTGs) attached to HIV-1 gp120, the crystal structure of AH in complex with MB has been determined. The AH molecule is composed of three identical structural modules, each of which has a pocket in which an MB molecule is bound adopting a bracket-shaped conformation. This conformation is stabilized through two weak C—H...O hydrogen bonds facilitated by the α(1–2) linkage. The binding features in the three pockets are quite similar to each other, in accordance with the molecular pseudo-threefold symmetry generated from the three tandem repeats in the amino-acid sequence. The shape of the pocket can accept two neighbouring hydroxyl groups of the O3and O4atoms of the equatorial configuration of the second mannose residue. To recognize these atoms through hydrogen bonds, an Asp residue is located at the bottom of each pocket. Tyr and Leu residues seem to block the movement of the MB molecules. Furthermore, the O1atom of the axial configuration of the second mannose residue protrudes from each pocket into an open space surrounded by the conserved hydrophobic residues, suggesting an additional binding site for the third mannose residue of the branched D1 chain of HMTGs. These structural features provide strong evidence indicating that AH is only highly specific for MB and would facilitate the highly specific affinity of AH for any glycoprotein carrying many HMTGs, such as HIV-1 gp120.

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