Synthesis of 7-Acyl-2,4-disubstituted Pteridines by Radical Nucleophilic Substitution and Displacement Reactions

Pteridines ◽  
2004 ◽  
Vol 15 (4) ◽  
pp. 129-148 ◽  
Author(s):  
Thomas Döring ◽  
Romesh C. Boruah ◽  
Wolfgang Pfleiderer
Keyword(s):  
Nucleophilic Substitution ◽  
Uv Spectra ◽  
Structural Modifications ◽  
Cyclic Amines ◽  
H Nmr ◽  
Substitution Mechanism ◽  
Acyl Radicals ◽  
Elemental Analyses ◽  
Displacement Reactions ◽  
Pteridine Derivatives

Abstract 2,4-Disubstituted pteridine derivatives (1-3) react with acyl radicals very selectively in position 7 by a nucleophilic Substitution mechanism (4-10). Oxidation of the 2-methylthio group proceeds with m-chloroperbenzoic acid in good yields to the corresponding 7-acyl-2-methylsulfonyl-4-aminopteridines (11-16). The methylsulfonyl group can easily been displaced by nucleophiles such as aliphatic amines (27, 29, 32-42, 45), cyclic amines (56-61), aromatic amines (30, 31) and amino acids (43-54). Oxygen nucleophiles lead to 7-acyl-isopterin derivatives (62-66). The acyl side-chain is also prone to structural modifications leading to the corresponding secondary alcohols on NaBH4 reduction (74-77) or to imino derivatives on reactions with amines (67-73) which can analogously been reduced to 2,4-disubstituted 7-( l-aminoalkyl)pteridines (80-85). An interesting H-shift was observed during heating of 32, 78 and 79 with benzylamine leading not to the benzylimines but the isomeric benzylideneamino derivatives 86-88. Various acetylations by acetic anhydride (AC2O) gave 89-93 and reduction of the pyrazine moiety to the 5,6,7,8-tetrahydro-pteridine derivatives 94-96 proceeded in the expected manner. The characterization of ther newly synthesized pteridine derivatives was performed by 1H-NMR spectra, UV-spectra and elemental analyses. Measurements of the basic pKa values of a selection of 2,4,7-trisubstituted pteridines were pteridines to characterize the dication, monocation and the neutral species by their UV-spectra.

Pteridines, CXVI. (1) Synthesis and Reactivity of 6-Substituted l,3-Dimethyl-7-hydroxylumazines and 7-Substituted l,3-Dimethyl-(5H)-lumazin-6-ones

Pteridines ◽  
2005 ◽  
Vol 16 (4) ◽  
pp. 184-189 ◽  
Author(s):  
Reinhardt Arendt ◽  
Wolfgang Pfleiderer
Keyword(s):  
Hydroxamic Acid ◽  
Uv Spectra ◽  
Phenyl Derivative ◽  
H Nmr ◽  
Step Procedure ◽  
Elemental Analyses ◽  
Acidic Conditions ◽  
Cyclic Hydroxamic Acid

Abstract 6-Substituted 1,3-dimethyl-7-hydroxylumazines (5-7) have been synthesized from 1,3-dimethyluracil-5,6- diamine (1) and a-ketoacid esters (2-4) under weakly acidic conditions. The isomeric 7-substituted 1,3-dimethyllumazin- 6-ones (18-20) resulted from a regioselective Boon synthesis starting from 6-chloro-l,3-dimethyl-5- nitrouracil (8) and α-aminoacid esters (9-11) in a three-step procedure. H202 oxidations led with 6 and 7 to the corresponding 5-N-oxides (21, 22) whereas in the lumazin-6-onc scries only the 7-phenyl derivative (20) reacted also at N-5 position forming a cyclic hydroxamic acid (23). The newly synthesized compounds have been characterized by elemental analyses,1H-NMR and UV spectra based upon pKa-determinations.

Synthesis and Properties of Condensed Lumazine-Ringsystems

Pteridines ◽  
2002 ◽  
Vol 13 (3) ◽  
pp. 65-72 ◽  
Author(s):  
Khaled Abou-Hadeed ◽  
Wolfgang Pfleiderer
Keyword(s):  
Uv Spectra ◽  
Reaction Products ◽  
Isomeric Mixture ◽  
H Nmr ◽  
Structural Assignment ◽  
Elemental Analyses ◽  
Methyl Derivatives

Abstract 1,3-Dimethyllumazine-6,7-diamine (1) and its monomethyl -(3,4) and monophenylamino (5) derivates are interesting starting materials for the synthesis of imidazo[4,5-g] (6-22) and pyrazino[2,3-g]lumazines (23-26). Ringclosure proceeds under relative drastic conditions and the resulting reaction products are highly fluorescent. Methylation of 5,7-dimethyll-imidazo[4,5-g)lumazine (6) led to an isomeric mixture of the 1- (17) and 3-methyl derivatives (7) which could be separated chromatographically. Their structural assignment was based on unambiguous syntheses heating 4 and 3, respectively, with formamide under reflux for ringclosure. The newly synthesized compounds have been characterized by 1H-NMR and UV-spectra as well as elemental analyses.

The preparation of 3-amino-3-deoxy-1,2-O-isopropylidene-α-L-erythrofuranose, 3-amino-3-deoxy-1,2-O-isopropylidene-β-D-threofuranose and their derivatives

1980 ◽  
Vol 45 (12) ◽  
pp. 3378-3390 ◽  
Author(s):  
Jiří Jarý ◽  
Milena Masojídková ◽  
Ivan Kozák ◽  
Miroslav Marek ◽  
Jan Staněk
Keyword(s):  
Nucleophilic Substitution ◽  
Sodium Azide ◽  
Sodium Benzoate ◽  
Nmr Spectra ◽  
Subsequent Reduction ◽  
H Nmr ◽  
Amino Derivatives

The title amino derivatives VI and XIV were prepared by nucleophilic substitution of p-toluenesulfonyl derivatives II and XVII with sodium azide or hydrazine and subsequent reduction. Nucleophilic substitution of compounds II and XVII with sodium benzoate was also investigated. The 1H NMR spectra of the substances prepared are discussed.

Azaoxa Macrocyclic and Acyclic Complexesof Lanthanides

1998 ◽  
Vol 63 (3) ◽  
pp. 363-370 ◽  
Author(s):  
Violetta Patroniak-Krzyminiewska ◽  
Wanda Radecka-Paryzek
Keyword(s):  
Schiff Base ◽  
Spectral Data ◽  
Macrocyclic Ligand ◽  
Lanthanide Ions ◽  
H Nmr ◽  
Elemental Analyses ◽  
Acyclic Complexes ◽  
Schiff Base Cyclocondensation

The template reactions of 2,6-diacetylpyridine with 3,6-dioxaoctane-1,8-diamine in the presence of dysprosium(III), thulium(III) and lutetium(III) chlorides and erbium(III) perchlorate produce the complexes of 15-membered macrocyclic ligand with an N3O2 set of donor atoms as a result of the [1+1] Schiff base cyclocondensation. In contrast, analogous reactions involving the lighter lanthanide ions (lanthanum(III), samarium(III) and europium(III)) yield the acyclic complexes with terminal acetylpyridyl groupings as products of the partial [2+1] condensation. The complexes were characterized by spectral data (IR, UV-VIS, 1H NMR, MS), and thermogravimetric and elemental analyses.

Synthesis and Antituberculotic Activity of Some Substituted 3-Arylamino-5-cyano-2-pyrazinecarboxamides

1995 ◽  
Vol 60 (7) ◽  
pp. 1236-1241 ◽  
Author(s):  
Martin Doležal ◽  
Jiří Hartl ◽  
Antonín Lyčka ◽  
Vladimír Buchta ◽  
Želmíra Odlerová
Keyword(s):  
Nucleophilic Substitution ◽  
Elemental Analysis ◽  
Nmr Spectra ◽  
Substituted Anilines ◽  
H Nmr

Nucleophilic substitution of 3-chloro-5-cyano-2-pyrazinecarboxamide by substituted anilines afforded substituted 3-arylamino-5-cyano-2-pyrazinecarboxamides I-X. The structures of compounds were confirmed by elemental analysis, UV, IR and 1H NMR spectra. The assessment of in vitro antimycotic and antimycobacterial activities of the compounds was carried out. The highest antituberculotic activity against M. tuberculosis in this series was shown by 3-anilino- 5-cyano-2-pyrazinecarboxamide (I), whose efficacy was the same as that of pyrazinecarboxamide.

scholarly journals Microwave-assisted synthesis and characterization of some optically active poly(ester-imide) thermoplastic elastomers

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Saeed Zahmatkesh ◽  
Abdol Reza Hajipour
Keyword(s):  
Thermal Analyses ◽  
Specific Rotation ◽  
Thermoplastic Elastomers ◽  
Optically Active ◽  
Microwave Assisted Synthesis ◽  
H Nmr ◽  
Microwave Assisted ◽  
Diacid Chloride ◽  
Elemental Analyses

AbstractPyromellitic dianhydride (1) was reacted with L-leucine (2) to result in [N,N'-(pyromellitoyl)-bis-L-leucine diacid] (3). This compound (3) was converted to N,N'-(pyromellitoyl)-bis-L-leucine diacid chloride (4) by reaction with thionyl chloride. The microwave-assisted polycondensation of this diacid chloride (4) with polyethyleneglycol-diol (PEG-200) and/or three synthetic bisphenols furnish a series of new PEIs and Co-PEIs in a laboratory microwave oven (Milestone). The resulting polymers and copolymers have inherent viscosities in the range of 0.31- 0.53 dl g-1. These polymers are optically active, thermally stable and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc and sulfuric acid. All of the above polymers were fully characterized by IR spectroscopy, 1H NMR spectroscopy, elemental analyses, specific rotation and thermal analyses. Some structural characterizations and physical properties of these optically active PEIs and Co-PEIs are reported.

Effects of Medium and Substituents on Dissociationof 4,4'-Disubstituted Bis(benzenesulfon)imides

1996 ◽  
Vol 61 (8) ◽  
pp. 1205-1214 ◽  
Author(s):  
Miroslav Ludwig ◽  
Pavel Štverka
Keyword(s):  
Latent Variables ◽  
Dissociation Constants ◽  
Substituent Effects ◽  
Principal Component ◽  
H Nmr ◽  
Base Process ◽  
Elemental Analyses ◽  
Substituent Constants ◽  
Model Substances ◽  
Strong Acids

Ten 4,4'-disubstituted bis(arenesulfon)imides of the general formula XC6H4SO2NHSO2C6H4X have been synthesized and their structures confirmed by their 1H NMR spectra. Elemental analyses are presented for the compounds not yet described. The dissociation constants of these model substances have been measured potentiometrically in pyridine, dimethylformamide, methanol, ethanol, propylene carbonate, acetone, acetonitrile, 1,2-dichloroethane and tetramethylene sulfone. The pKHA values obtained have been correlated with three sets of the Hammett substituent constants and the results have been used to discuss the solvent and substituent effects on the dissociation of the compounds studied. Sulfonimides with electron-acceptor substituents behave as rather strong acids in some solvents (pyridine, dimethylformamide, methanol and ethanol), whereas normal substituent dependences are found in other solvents. The experimental data have also been interpreted with the help of the statistical methods based on latent variables. From the calculations it follows that only the first principal component, which correlates well with the substituent constant sets adopted, is statistically significant in describing the substituent effect on the acid-base process studied.

scholarly journals Synthesis, Characterization, and Antimicrobial Activity of Methyl-2-aminopyridine-4-carboxylate Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
S. Nagashree ◽  
P. Mallu ◽  
L. Mallesha ◽  
S. Bindya
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Studies ◽  
H Nmr ◽  
Chemical Structures ◽  
Elemental Analyses ◽  
Ft Ir

A series of methyl-2-aminopyridine-4-carboxylate derivatives,3a–f,were synthesized in order to determine theirin vitroantimicrobial activity. The chemical structures of the synthesized compounds were confirmed by elemental analyses, FT-IR, and1H NMR spectral studies. Among the synthesized compounds,3cand3dshowed good antimicrobial activity compared to other compounds in the series.

Synthesis, Characterization and Complexation Studies with K + and Ca2+ Cations of trans-1.2-Cyclohexanedioxydiacetamides

1988 ◽  
Vol 43 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Whei Oh Lin ◽  
Maria C. B. V. de Souza ◽  
Helmut G. Alt
Keyword(s):  
Nmr Spectroscopy ◽  
Mass Spectroscopy ◽  
H Nmr ◽  
Coordination Sites ◽  
Complexation Studies ◽  
Ir And Nmr Spectroscopy ◽  
Elemental Analyses ◽  
C Nmr

The synthesis of trans-1.2-cyclohexanedioxydiacetamides starting with trans-1.2-cyclohexane-diol is described. Eleven of these compounds are characterized by IR, 1H NMR, 13C NMR and mass spectroscopy as well as elemental analyses. Most of these compounds are suitable ionophors for the cations K+ and Ca2+. The coordination sites of these ligands in the 1:2 complexes were determined by IR and NMR spectroscopy

STRUCTURAL FEATURES, COMPUTATIONAL STUDIES AND BIOLOGICAL ANALYSIS: SCHIFF’S BASE LIGAND AND ITS COORDINATION COMPOUNDS

INDIAN DRUGS ◽  
2021 ◽  
Vol 58 (07) ◽  
pp. 22-31
Author(s):  
Seema Gautam ◽  
Sulekh Chandra ◽  
Jugmendra Singh ◽  
Navneet Manav ◽  
Vinod K Paliwal ◽  
...  
Keyword(s):  
Metal Ions ◽  
Coordination Compounds ◽  
Computational Study ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Structural Features ◽  
Schiff’S Base ◽  
H Nmr ◽  
Diffusion Technique ◽  
Elemental Analyses

Structure and biological application based analysis has been carried out for Schiff’s base ligand containing nitrogen and sulphur donor atoms and also for a series of its coordination compounds. Ligand benzil-bis(5-amino-1,3,4-thiadiazole-2-thiol) (L) has been prepared and structural features of ligand investigated by elemental analyses, IR, 1 H-NMR, mass spectra and molecular modeling studies. The chemical reaction of the prepared ligand with metal ions afforded mononuclear coordination compounds of Mn(II) and Co(II) metal ions. The characterization of the coordination compounds is being based on the techniques i.e. elemental analysis, infra-red, UV-visible as well as melting point, molar conductivity and magnetic moment measurement. A computational study has been done to understand the miscellaneous coordination modes of ligand to metal ions. Characterization result shows that coordination compounds exhibit a six coordinated geometrical arrangement i.e. octahedral geometry. The biological inhibition zone (antifungal and antibacterial activities) of synthesized compounds, i.e. ligand and its coordination compounds, has been monitored using well diffusion technique

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