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.

Formation, reactions, and NMR spectra of 1,20-cycloatidanes

1992 ◽  
Vol 70 (5) ◽  
pp. 1397-1405 ◽  
Author(s):  
Oliver E. Edwards ◽  
Dusan Dvornik ◽  
Ralph J. Kolt ◽  
Barbara A. Blackwell
Keyword(s):  
Acetic Anhydride ◽  
Alkaline Hydrolysis ◽  
Nmr Spectra ◽  
Ring Current ◽  
Cyclopropane Ring ◽  
C Nmr

Imines derived from the alkaloid atisine gave N-acetyl 1,20-cycloatidane derivatives when heated with acetic anhydride. Vigorous alkaline hydrolysis cleaved the cyclopropane ring, regenerating the parent imine. The 1H and 13C NMR spectra of several 1,20-cyclo derivatives have been assigned and compared to those of the parent imines 2. All of the N-acetyl compounds showed doubling of the majority of the NMR resonances, due to amide rotamers. The effects of the cyclopropane ring current are noted.

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.

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.

Immobilisierung von Cytidin und Uridin über 2'.3'-O-cyclische Acetalderivate an Agarose / Im mobilisation of Cytidine and Uridine via 2',3'-O-Cyclic Acetal Derivatives to Agarose

1978 ◽  
Vol 33 (1-2) ◽  
pp. 56-60 ◽  
Author(s):  
Frank Seela ◽  
Helmut Roseineyer
Keyword(s):  
Nmr Spectroscopy ◽  
Absolute Configuration ◽  
Alkaline Hydrolysis ◽  
Carboxyl Groups ◽  
Cyclic Acetal ◽  
Ethyl Group ◽  
Ethyl Levulinate ◽  
The Absolute ◽  
Hydrolysis Of ◽  
C Nmr

Abstract Condensation of cytidine or uridine with ethyl levulinate leads to the acetals 1a/2a. The reac­tion would be expected to give mixtures of diastereoisom ers. As shown by 1H and 13C NMR spectroscopy only one diastereoisomer is formed. By spectroscopic comparison of 1a/2a with the corresponding adenosine acetal the absolute configuration of the new chiral centre was found to be R. The acetal m ethyl group of 1a/2a in exo-location can serve to distinguish the two m ethyl signals of O-2′,3′-isopropylidenecytidine and -uridine in the NM R spectra. On alkaline hydrolysis of the esters the acids 1b and 2b are formed, which can be condensed through their carboxyl groups with 6-aminohexylagarose. The affinity resins 3 and 4 contain 7.1 μmol and 7.6 μmol ligand/g moist gel respectively. A biospecificity of the new polymers to cytidine-and uridine converting enzymes is expected.

Synthesis of 5-Phenylcytosine Nucleoside Derivatives

1996 ◽  
Vol 61 (4) ◽  
pp. 645-655 ◽  
Author(s):  
Marcela Krečmerová ◽  
Hubert Hřebabecký ◽  
Antonín Holý
Keyword(s):  
Acetic Anhydride ◽  
Thionyl Chloride ◽  
Alkaline Hydrolysis ◽  
Hydrogen Bromide ◽  
Analogous Reaction ◽  
Final Reaction Product ◽  
Cyclic Sulfite ◽  
Higher Temperature ◽  
Hydrolysis Of ◽  
Tin Tetrachloride

Reaction of silylated 5-phenylcytosine with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribose, catalyzed with tin tetrachloride, and subsequent methanolysis afforded 5-phenylcytidine (2). This compound reacted with thionyl chloride in acetonitrile to give cyclic sulfite 3 which on heating in dimethylformamide was converted into 2,2'-anhydro-1-(β-D-arabinofuranosyl)-5-phenylcytosine (4). Analogous reaction of compound 2 with thionyl chloride at reflux gave 5'-chloro-5'-deoxy-2',3'-cyclic sulfite 5. Its heating in dimethylformamide afforded 5'-chloro-2,2'-anhydro derivative 6, mild alkaline hydrolysis led to 5'-chloro-5'-deoxy-5-phenylcytidine (7). Alkaline hydrolysis of 5-phenyl-2,2'-anhydrocytidine (4) gave 5-phenylcytosine arabinoside 8, whereas the 2,2'-anhydro derivative 6 afforded 1-(5-chloro-5-deoxy-β-D-arabinofuranosyl)-5-phenylcytosine (11). At higher temperature, the final reaction product was 2,5'-anhydro-5-phenylcytidine (12). 5'-Chloro-5'-deoxynucleosides 7 and 11 reacted with tri-n-butyl- stannane to give 5'-deoxyribofuranosyl and 5'-deoxyarabinofuranosyl derivatives 15 and 16. 5-Phenylcytidine (2) was converted into the N4-acetate 17 with acetic anhydride. Further reaction with acetic anhydride and hydrogen bromide in acetic acid afforded a mixture of peracetylated 2'-bromo and 3'-bromo derivatives 18 and 19. Reaction with Zn/Cu couple gave 5'-O-acetyl-5-phenyl-2',3'-didehydro derivative 20 and 2',3',5'-tri-O-acetyl-5-phenylcytidine (21). Compound 20 was deblocked to 1-(2,3-dideoxy-β-D-glycero-pent-2-enofuranosyl)-5-phenylcytosine (22). Catalytic hydrogenation of compound 20 over palladium and subsequent deblocking of the protected 2',3'-dideoxy derivative 23 gave 1-(2,3-dideoxy-β-D-glycero-pentofuranosyl)-5-phenylcytosine (24).

Characterization of lignin residues derived from the alkaline hydrolysis of glycol lignin

1990 ◽  
Vol 68 (1) ◽  
pp. 82-89 ◽  
Author(s):  
Ronald W. Thring ◽  
Esteban Chornet ◽  
Jean Bouchard ◽  
Pierre F. Vidal ◽  
Ralph P. Overend
Keyword(s):  
Alkaline Hydrolysis ◽  
Size Exclusion ◽  
Absorption Intensity ◽  
Molecular Weights ◽  
Carbon Carbon Bonds ◽  
Lower Oxygen ◽  
Exclusion Chromatography ◽  
Hydrolysis Of ◽  
C Nmr

Lignin residues from the alkaline hydrolysis of solvolytic lignin have been characterized by elemental analysis, size exclusion chromatography, Fourier transform infrared spectroscopy, 13C NMR, and for methoxyl content. All lignin residues were found to have higher carbon and lower oxygen contents than the original glycol lignin. Methoxyl contents decreased with increasing severity of treatment. All treated lignins have lower molecular weights than the original, which is indicative of the extensive depolymerization of glycol lignin by alkaline hydrolysis. The appearance of new bands in the 3050–2800 cm−1 and 900–800 cm−1 regions in the infrared spectra along with increasing absorption intensity under more severe conditions demonstrates that, despite the tendency to depolymerization, new carbon–carbon bonds are formed due to repolymerization reactions. 13C NMR revealed that extensive cleavage of the side chains and β-O-4 interunit linkages had occurred during alkaline hydrolysis and that the new bonds formed due to condensation reactions at higher severities are of the methine, methylene, methyl and carboxyl types. Keywords: residual lignins, alkaline hydrolysis, characterization.

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).

Alkaline Hydrolysis of Substituted Phenyl Acetates Catalyzed by Quaternary Ammonium Salts

1993 ◽  
Vol 58 (12) ◽  
pp. 2891-2895 ◽  
Author(s):  
Jiří Kulič ◽  
Jiří Sussenbek ◽  
Aleš Ptáček
Keyword(s):  
Ammonium Chloride ◽  
Alkaline Hydrolysis ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Ammonium Bromide ◽  
Hexadecyltrimethylammonium Bromide ◽  
Rate Data ◽  
Hammett Equation ◽  
Efficient Catalyst ◽  
Hydrolysis Of

Alkaline hydrolysis if the phenyl acetates CH3COOC6H4X (X = 4-NO2, 3-NO2, 3-Cl, H, 4-CH3, 3-CH3, and 4-OCH3) in the presence of hexadecyltris(2-hydroxyethyl)ammonium chloride, bis(2-hydroxyethyl)hexadecyl(methyl)ammonium bromide, and hexadecyltrimethylammonium bromide has been studied. Comparison of the rates of the hydrolysis for the above tenzides showed that the most efficient catalyst is the hexadecyltris(2-hydroxyethyl)ammonium chloride. In all cases, the rate data correlated well with structure effects by the Hammett equation.

1,4-Bis(p-pentazolylphenyl)butan, 1-p-Azidophenyl-4-p-pentazolylphenyl- butan und 1,4-Bis(p-azidophenyl)butan / 1,4-Bis(p-pentazolylphenyl)butane, 1-p-Azidophenyl-4-p-pentazolylphenyl-butane and 1,4-Bis(p-azidophenyl)butane

2004 ◽  
Vol 59 (6) ◽  
pp. 716-720 ◽  
Author(s):  
Frank Biesemeier ◽  
Klaus Harms ◽  
Ulrich Müller
Keyword(s):  
Low Temperature ◽  
Sodium Azide ◽  
Rate Constants ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Fine Powder ◽  
Space Group ◽  
H Nmr ◽  
Diazonium Ions ◽  
C Nmr

1,4-Bis(p-pentazolylphenyl)butane (1), 1-p-azidophenyl-4-p-pentazolylphenyl-butane (2) and 1,4-bis(p-azidophenyl)butane (3) were obtained by the reaction of 1,4-diphenylbutane-4’,4”- bis(diazonium) ions with sodium azide in methanol at −50 °C. In the 1H and 13C NMR spectra the three compounds can be distinguished unequivocally. At −50 °C a mixture with a composition 1:2:3 of 10:30:60 was obtained. By recrystallization first from dichloromethane/methanol and then from dichloromethane/petroleum ether the pentazole components were enriched to a composition ratio of 21:62:17. The rate constants of the decompositions 1→2 and 2→3 at 0 °C were determined from the variation of the 1H NMR intensities. At room temperature all of the material is converted to 3. 3 crystallizes in two monoclinic modifications. At −70 °C a modification 3-LT having space group P21/c (a = 950.8, b = 1192.6, c = 701.3 pm, β = 92.55°, Z = 2; R = 0.075) was obtained. The modification crystallizing at room temperature (3-HT) has space group I2/a (a = 1514.5, b = 498.1, c = 2027.9 pm, β = 92.73°, Z = 4; R = 0.040). Whereas both modifications consist of nearly identical molecules, their packings are quite different. When the low temperature modification is warmed to room temperature, its crystals jump like flees and are disrupted to a fine powder.

Synthesis of Novel 4-Amino-5-(disubstituted amino)-2-phenyl-2H-pyridazin-3-ones

1997 ◽  
Vol 62 (5) ◽  
pp. 800-808 ◽  
Author(s):  
Václav Konečný ◽  
Jozefína Žúžiová ◽  
Štefan Kováč ◽  
Tibor Liptaj
Keyword(s):  
Acetic Anhydride ◽  
Alkaline Hydrolysis ◽  
Acetyl Chloride ◽  
Cyclic Amines ◽  
Hydrolysis Of

Substituted 4-amino-2-phenyl-2H-pyridazin-3-ones 5a-5j have been prepared from 4-amino-5-chloro-2-phenyl-2H-pyridazin-3-one 1 which on reactions with acetyl chloride or acetic anhydride gives 4-acetylamino derivative 2 or 4-diacetylamino derivative 3, respectively. Derivatives 2 and 3 with dialkylamines and cyclic amines yielded appropriate 4-acetylamino-5-(disubstituted amino)-2-phenyl-2H-pyridazin-3-ones 4a-4j. Subsequent alkaline hydrolysis of the acetylamino derivatives 4a-4j let to the title compounds 5a-5j, which were screened for pesticidal activity, but none of them reached activity of the used standards.

Sign in / Sign up

Export Citation Format

Share Document