Action of Grignard reagents on hexuronic esters and attempted dehydration of tertiary alcohols to give hex-5-enopyranosides

1976 ◽  
Vol 54 (11) ◽  
pp. 1708-1713 ◽  
Author(s):  
Gerald O. Aspinall ◽  
Osamu Igarashi ◽  
Thinnayam N. Krishnamurthy ◽  
Walter Mitura ◽  
Masuo Funabashi
Keyword(s):  
Nmr Spectra ◽  
Grignard Reagents ◽  
Glycosidic Linkage ◽  
Tertiary Alcohols ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
Controlled Hydrolysis ◽  
C Nmr

The attempted formation of hex-5-enopyranosides from glycosiduronates by the action of Grignard reagents followed by dehydration affords hex-6-enopyranosides or 1,6-anhydrohexopyranoses as major products. 13C nmr spectra of 6,6-di-C-substituted hexose derivatives are compared with those of a number of structurally related compounds. The formation of a hex-5-enopyranoside and the selective cleavage of its glycosidic linkage is illustrated by the synthesis and controlled hydrolysis of methyl 6-O-(6-deoxy-2,3,4-tri-O-methyl-β-L-arabino-hex-5-enopyranosyl)-2,3,4-tri-O-methyl-β-D-glucopyranoside(2).

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.

Δ-Sym-cis and Δ-unsym-cis-carbonato-(2S,2'S)-2,2'-ethylene-bis(2-amino-3-methylbutanoato)cabaltate(III) isomers

1987 ◽  
Vol 52 (6) ◽  
pp. 1488-1493 ◽  
Author(s):  
František Jursík ◽  
Samir Abdel-Moez
Keyword(s):  
Acid Hydrolysis ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Tetradentate Ligand ◽  
Steric Crowding ◽  
The Absolute ◽  
Kinetic Effects ◽  
Hydrolysis Of ◽  
C Nmr

The tetradentate ligand (2S,2'S)-2,2'-ethylene-bis(2-amino-3-methylbutanoato) (eddval) is coordinated in the [Co(eddval)CO3]- anion to give 88% of Δ-sym-cis and 12% of Δ-unsym-cis isomers. The stereospecific formation of the Δ-sym-cis isomer is explained by steric crowding in the Λ-sym-cis isomer. The predominance of the sym-cis isomer indicates that the synthesis is also influenced by kinetic effects. These are particularly pronounced in the case of the Δ-unsym-cis isomer which for steric reasons is thermodynamically less stable than the Λ-unsym-cis isomer. The secondary nitrogen atoms in the Δ-sym-cis isomer are of the R configuration whereas in the Δ-unsym-cis isomer they have configuration R and S. The absolute configuration of the isomers has been determined from their absorption, CD, 1H and 13C NMR spectra. Acid hydrolysis of Δ-sym-cis-[Co(eddval)CO3]- proceeds with retention of configuration to give the Δ-[Co(eddval)(H2O)2]+ isomer.

Approaches to the synthesis of triterpenoids. VI. The synthesis of 3,3,10aβ-trimethyl-l,2,3,4,4aβ,5,8,9,10,10a-decahydrophenanthren-7(6H)-one, a potential intermediate for pentacyclic triterpene synthesis

1981 ◽  
Vol 59 (6) ◽  
pp. 1010-1017 ◽  
Author(s):  
John W. ApSimon ◽  
David Moir ◽  
Kazuyuki Yamasaki
Keyword(s):  
Nmr Spectra ◽  
Efficient Synthesis ◽  
Pentacyclic Triterpene ◽  
Naturally Occurring ◽  
Ring Junction ◽  
Triterpene Synthesis ◽  
Synthetic Intermediate ◽  
Related Compounds ◽  
C Nmr

Investigations of the CDE ring construction of naturally occurring triterpenoids are described. The efficient synthesis of 3,3,10aβ-trimethyl-1,2,3,4,4aβ,5,8,9,10,10a-decahydrophenanthren-7(6H)-one(25) has been achieved. The D/E ring junction of the molecule, as well as that of related compounds, has been established by the use of 13C nmr spectra. The synthetic intermediate 25 can be considered as a key substance for a synthetic entry to friedelin (1) in addition to β-amyrin (23).

Synthesis of Several Hydroxylated 23-(Benzimidazol-2-yl-, Benzoxazol-2-yl and Benzothiazol-2-yl)norcholanes and Some Related Compounds

1995 ◽  
Vol 60 (2) ◽  
pp. 257-275 ◽  
Author(s):  
Thi Thu Huong Nguyen ◽  
Jiří Urban ◽  
Eva Klinotová ◽  
Jan Sejbal ◽  
Jiří Protiva ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Succinic Anhydride ◽  
Benzimidazole Derivative ◽  
Acid Chlorides ◽  
H Nmr ◽  
Hydroxy Compounds ◽  
Related Compounds ◽  
Anti Hiv ◽  
C Nmr

The bile acids Ia - Id (lithocholic, chenodeoxycholic, deoxycholic, cholic) and their derivatives (O-acetylated acids and O-acetylated acid chlorides) reacted under various conditions with 1,2-diaminobenzene, 2-aminophenol and 2-aminothiophenol and afforded the title benzimidazoles II and VII, benzoxazoles V and benzothiazoles VI. Alkylation of the benzimidazole derivative IIa with 2-dimethylaminoethyl chloride resulted in 3α-hydroxy-23-[1-(2-dimethylaminoethyl)ben zimidazol-2-yl]- norcholane (IVa). The use of 1,2-diamino-4-methylbenzene enabled the preparation of 3α-acetoxy-23-[5(6)-methylbenzimidazol-2-y l]norcholane (VIII). Reactions of the 3α-hydroxy compounds IVa, Va and VIa with succinic anhydride resulted in the hemisuccinates IVi - VIi. The boric acid mediated condensation of O-acetyllithocholic acid (Ie) with 3,4-diaminopyridine gave compound X which was transformed to 3α-acetoxy-23-[1H-imidazo(4,5- c)pyridin-2-yl]norcholane (IX). The structure of the products was corroborated by the mass, IR, 1H NMR and 13C NMR spectra. Some of the compounds were tested for antileukemic and for the anti-HIV activity in vitro.

On the chemistry and high field nuclear magnetic resonance spectroscopy of rapamycin

1980 ◽  
Vol 58 (6) ◽  
pp. 579-590 ◽  
Author(s):  
John A. Findlay ◽  
Lajos Radics
Keyword(s):  
High Field ◽  
Nmr Spectra ◽  
Resonance Spectroscopy ◽  
X Ray ◽  
Conformational Isomers ◽  
H Nmr ◽  
Neutral Compounds ◽  
Complete Assignment ◽  
Hydrolysis Of ◽  
C Nmr

Base catalysed hydrolysis of rapamycin (C51H79NO13) affords six neutral compounds identified by chemical and spectroscopic means as 2a, 3b, 3d, 5, 2,4-dimethylphenol, and L(−)-piperidine-2-carboxylic acid 6, and whose generation has been plausibly rationalized. These findings as well as detailed analyses of 13C nmr and 1H nmr spectra provide independent corroboration of the X-ray derived rapamycin crystal structure 1. Structurally homogeneous in the solid state, rapamycin is found to occur in solutions as a mixture of two conformational isomers (approximately 4:1). Through nearly complete assignment of the high field 1H (400 MHz) and 13C (100.6 MHz) nmr spectra, the isomerism is shown to be associated with trans–cis rotation of an amidic bond within the 31-membered macrolide ring. The predominant form corresponds to the conformer portrayed by X-ray analysis.

Synthesis and Reactions of Furo[3,2-b]pyrrole Type Aldehydes

1993 ◽  
Vol 58 (9) ◽  
pp. 2139-2149 ◽  
Author(s):  
Alžbeta Krutošíková ◽  
Miloslava Dandárová ◽  
Juraj Alföldi
Keyword(s):  
Acetic Anhydride ◽  
Ammonium Chloride ◽  
Alkaline Hydrolysis ◽  
Sodium Azide ◽  
Nmr Spectra ◽  
Hydrolysis Of ◽  
C Nmr

The synthesis of ethyl 2-formyl-4-benzylfuro[3,2-b]pyrrole-5-carboxylate (I) is described. A series of furo[3,2-b]pyrrole-2-carbaldehyde 2,6-dialkylphenylhydrazones (IIa - IIg) and dimethylhydrazones (IIIa - IIId) were prepared. By reaction of title compounds with hydroxylammonium chloride in acetic anhydride in the presence of pyridine corresponding cyano-substituted compounds (IVa - IVd) were obtained. Alkaline hydrolysis of IVa - IVd gave Va - Vb and the reaction with sodium azide and ammonium chloride in dimethylformamide led to VIa - VId. the structure of the compounds have been proved by UV, IR, 1H and 13C NMR spectra.

scholarly journals Regenerablity and Stability of Antibacterial Cellulose Containing Triazine N-halamine

2016 ◽  
Vol 11 (1) ◽  
pp. 155892501601100 ◽  
Author(s):  
Lin Li ◽  
Kaikai Ma ◽  
Yin Liu ◽  
Ying Liu ◽  
Rong Li ◽  
...  
Keyword(s):  
Water Solution ◽  
Triazine Derivative ◽  
Chlorine Bleaching ◽  
Nmr Study ◽  
Antimicrobial Function ◽  
Application Fields ◽  
Hydrolysis Of ◽  
Release Testing ◽  
Controlled Hydrolysis ◽  
C Nmr

A reactive triazine derivative, 2,4-dichloro-6-hydroxy-1,3,5-triazine (DCHT), was prepared through the controlled hydrolysis of cyanuric chloride in water solution. The reaction was characterized with 13C NMR study. The reaction solutions could be directly used to treat cellulose fibers. A pad-dry-cure method was employed to immobilize the triazine derivative onto cotton. The covalently bound triazine moieties on cotton could be transformed into N-halamine structures after a chlorine bleaching treatment. The biocidal efficacies of the treated samples with different chlorine loadings were further examined. The storage and release testing showed that the antimicrobial function of the N-halamine modified cotton fabrics was durable and renewable. These advantages make the triazine N-halamine modified cotton as an attractive candidate in a broad range of application fields.

Formation of methyl 2-arylhydrazono-3-oxobutanoates and 2-arylhydrazono-3-oxobutanenitriles during the coupling reaction of arenediazonium ions with methyl 3-aminocrotonate and 3-aminocrotononitrile

1995 ◽  
Vol 73 (2) ◽  
pp. 169-175 ◽  
Author(s):  
D. Sean Brown ◽  
Jason V. Jollimore ◽  
Marcus P. Merrin ◽  
Keith Vaughan ◽  
Donald L. Hooper
Keyword(s):  
Mass Spectrometry ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Diazonium Coupling ◽  
High Yields ◽  
Hydrolysis Of ◽  
C Nmr

Reaction of aryldiazonium salts with methyl 3-aminocrotonate (1) affords high yields of the methyl 2-arylhydrazono-3-oxobutanoates (4); analogous diazonium coupling with 3-aminocrotononitrile (2) gives the 2-arylhydrazono-3-oxobutanenitriles (5). The hydrazones are the product of diazonium coupling at the C2-vinylic carbon, concomitant with hydrolysis of the 3-amino substituent to the 3-oxo derivative; there is no evidence for the formation of a triazene (6), which would be the product of N-coupling. All hydrazones (4a–e and 5a–d) have been fully characterized by IR and 1H and 13C NMR spectroscopy; the NMR spectra of the methyl 2-arylhydrazono-3-oxobutanoates (4) suggest the presence of two isomeric intramolecularly H-bonded forms in solution. Selected compounds were further characterized by elemental analysis and mass spectrometry. A mechanism is proposed for the conversion of 1 or 2 into 4 or 5, and these observations are compared with previously reported observations of diazonium coupling reactions with unsaturated systems. Keywords: hydrazone, diazonium, aminocrotonate, aminocrotononitrile, hydrogen bonding.

Diisophorone and Related Compounds, Part 29. 3-Aminodiisophorane Derivatives

1991 ◽  
Vol 46 (4) ◽  
pp. 530-540 ◽  
Author(s):  
Frederick Kurzer ◽  
Jayantilal N. Patel
Keyword(s):  
Nmr Spectra ◽  
The Individual ◽  
Related Compounds ◽  
C Nmr

3-Aminodiisophor-2(7)-en-1-ol and homologues are obtained from the readily accessible 3-ketones by reduction of their respective ketoximes, and are characterized as suitable derivatives. The 3-(ω-phenylthioureido) compound undergoes cyclodehydration to a substituted 8,11a-methanocycloocta[d,e][3.1]benzthiazine. The structures of the individual compounds are correlated with their assigned 13C NMR spectra.

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