Basicity of substituted 2-phenyl-1,1,3,3- tetramethylguanidines and other bases in acetonitrile solvent

1989 ◽  
Vol 67 (4) ◽  
pp. 590-595 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Przemyslaw Pruszynski ◽  
Kohila Thanapaalasingham
Keyword(s):  
Solvent Effect ◽  
Phenyl Ring ◽  
Mean Value ◽  
General Purpose ◽  
Glass Electrode ◽  
Steric Effects ◽  
The Mean ◽  
Derivatives Of ◽  
Hammett Relationship ◽  
Electronic And Steric Effects

A series of 30 phenyl substituted derivatives of 2-phenyl-1,1,3,3-tetramethylguanidine was synthesized and the pKa value of each was measured in acetonitrile using a conventional, general purpose glass electrode. The slope of the Hammett relationship, for the para and meta substituted compounds, ρ = 2.18 ± 0.16, is significantly lower than ρ = 2.85 ± 0.06 found for anilines in water, even though the phenyl ring is attached directly to the basic centre in both cases. The influence of electronic and steric effects on the basicity of the compounds is discussed. The solvent effect on the basicity is also discussed, by comparison of the pKa values in acetonitrile and water. The mean value of [Formula: see text] is slightly higher than the value previously observed for ammonia and aliphatic amines, [Formula: see text]. Additionally, the pKa values were measured for seven other cyclic bases, including 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN). Keywords: 2-phenyl-1,1,3,3-tetramethylguanidines, pKa measurements.

scholarly journals N-Directed Pd-Catalyzed Photoredox-Mediated C–H Arylation for Accessing Phenyl-Extended Analogues of Biginelli/Suzuki-Derived Ethyl 4-Methyl-2,6-diphenylpyrimidine-5-carboxylates

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1071
Author(s):  
Savvas N. Georgiades ◽  
Persefoni G. Nicolaou ◽  
Nikos Panagiotou
Keyword(s):  
Organic Synthesis ◽  
Phenyl Ring ◽  
Room Temperature ◽  
Functional Group ◽  
Cross Coupling ◽  
Steric Effects ◽  
Biologically Relevant ◽  
Biginelli Condensation ◽  
Derivatives Of ◽  
Electronic And Steric Effects

The availability and application of direct, functional group-compatible C–H activation methods for late-stage modification of small-molecule bioactives and other valuable materials remains an ongoing challenge in organic synthesis. In the current study, we demonstrate that a LED-activated, photoredox-mediated, Pd(OAc)2-catalyzed C–H arylation, employing a phenyldiazonium aryl source and either tris(2,2′-bipyridine)ruthenium(II) or (2,2′-bipyridine)bis[3,5-di-fluoro-2-[5-(trifluoromethyl)-2-pyridinyl-kN][phenyl-kC]iridium(III) as photoredox initiator, may successfully produce unprecedented mono- and bis-phenyl derivatives of functionality-rich 2,6-diphenylpyrimidine substrates at room temperature. The series of 19 substrates employed herein, which share the biologically-relevant 4-methyl-2,6-diphenylpyrimidine-5-carboxylate scaffold, were generated via a synthetic route involving (3-component) Biginelli condensation, oxidative dehydrogenation of the obtained 3,4-dihydropyrimidin-2(1H)-one to 2-hydroxypyrimidine, O-sulfonylation, and Suzuki-Miyaura C–C cross-coupling. Submission of these substrates to pyrimidine-N-atom-directed C–H arylation conditions led to regioselective phenylation at the ortho site(s) of the pyrimidine-C2-connected phenyl ring, revealing substituent-dependent electronic and steric effects. A focused library of 18 mono- and 10 bis-phenyl derivatives was generated. Its members exhibit interesting 3D and peripheral substitution features that render them promising for evaluation in drug discovery efforts.

Substituted Derivatives of 10-Phenyl-9-Acetoxyanthracene. Absorption and emission spectra, quantum yield and lifetime of fluorescence

1975 ◽  
Vol 30 (5) ◽  
pp. 612-618 ◽  
Author(s):  
Janina Heidt ◽  
Józef Heidt ◽  
Janina Gronowska
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Oscillator Strengths ◽  
Steric Effects ◽  
Absorption And Fluorescence Spectra ◽  
Mean Lifetime ◽  
The Mean ◽  
Derivatives Of

Abstract Absorption The absorption and fluorescence spectra of five substituted derivatives of 10-phenyl-9-acetoxy-anthracene were measured and the oscillator strengths of the 1A→1La1A→1Bb and 1A→1Cb electronic vibration bands were determined. Comparison of the absorption spectra of these compounds to the unsubstituted molecule (anthracene) indicate the presence of bathochromic and steric effects. The fluorescence quantum yield and the mean lifetime of the fluorescence were also measured.

Conjugative interactions in 1-methylpyrrol-2-yl derivatives of the cyclic phosphazenes (NPF2)n (n = 3–6): the crystal and molecular structure of 1-methylpyrrol-2-ylheptafluorocyclotetraphosphazene

1982 ◽  
Vol 60 (4) ◽  
pp. 535-541 ◽  
Author(s):  
Rajendra D. Sharma ◽  
Steven J. Rettig ◽  
Norman L. Paddock ◽  
James Trotter
Keyword(s):  
Intramolecular Charge Transfer ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Mean Value ◽  
Full Matrix ◽  
Geometrical Features ◽  
Electron Release ◽  
The Mean ◽  
Cyclic Phosphazenes ◽  
Derivatives Of

1-Methylpyrroles, in which the 2-position is occupied by a pentafluorocyclotriphosphazenyl (1a), heptafluorocyclotetraphosphazenyl (1b), nonafluorocyclopentaphosphazenyl (1c), or undecafluorocyclohexaphosphazenyl group (1d), have been prepared from 2-lithio-1-methylpyrrole and the corresponding fluorophosphazene. Crystals of 1b are monoclinic, a = 17.300(2), b = 5.0281(3), c = 16.902(2) Å, β = 108.904(4)°, Z = 4, space group P2/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.038 and Rw = 0.047 for 1167 observed reflections. The N4P4 ring is nearly planar. The P—N bond lengths (corrected for libration) range from 1.524(5) to 1.562(5) Å with a mean value of 1.541(17) Å, and the mean ring angles are 122.9(20)° at phosphorus and 146.4(23)° at nitrogen. The geometry of the 1-methylpyrryl group shows no unexpected features, but the P—C bond (1.756(5) Å) is significantly shorter than in typical P-phenyl derivatives, and the P—F bond at the same atom is comparatively long (1.561(4) Å). Conjugative electron release from the pyrryl group, involving pπ–dπ bonding, is indicated both by these geometrical features and by the appearance of intramolecular charge transfer bands in the electronic spectra of 1(a–d).

scholarly journals Generalized Conformable Mean Value Theorems with Applications to Multivariable Calculus

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Francisco Martínez ◽  
Inmaculada Martínez ◽  
Mohammed K. A. Kaabar ◽  
Silvestre Paredes
Keyword(s):  
Research Work ◽  
Mean Value ◽  
Higher Order ◽  
Conformable Derivative ◽  
Mean Value Theorems ◽  
Classical Calculus ◽  
Multivariable Calculus ◽  
Conformable Derivatives ◽  
The Mean ◽  
Derivatives Of

The conformable derivative and its properties have been recently introduced. In this research work, we propose and prove some new results on the conformable calculus. By using the definitions and results on conformable derivatives of higher order, we generalize the theorems of the mean value which follow the same argument as in the classical calculus. The value of conformable Taylor remainder is obtained through the generalized conformable theorem of the mean value. Finally, we introduce the conformable version of two interesting results of classical multivariable calculus via the conformable formula of finite increments.

Long-period modulated superstructures in Pd-12.5 at.%Ce and Pd-15 at.%Ce alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 164-165
Author(s):  
Noriyuki Kuwano ◽  
Masaru Itakura ◽  
Kensuke Oki
Keyword(s):  
Electron Microscopy ◽  
Mean Value ◽  
Heavy Elements ◽  
Arc Furnace ◽  
X Ray ◽  
Long Period ◽  
Ultra High Purity ◽  
Heat Treated ◽  
Atomic Scattering ◽  
The Mean

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski
Keyword(s):  
Human Subjects ◽  
Coronary Thrombosis ◽  
Mean Value ◽  
Healthy Human ◽  
Protamine Sulphate ◽  
Soluble Fibrin ◽  
Fibrin Monomer ◽  
Dog Plasma ◽  
The Mean ◽  
Precipitable Protein

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

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