bluuebunny/crossref_metadata_2025 huggingface dataset:
α‐Silyl trimethylsilyl esters from aliphatic carboxylic Acid Dianions
Authors: Bellassoued M. , Dubois J. E. , Bertounesque E.
Published: September 2010

The synthesis of α‐silyl trimethylsilyl esters from aliphatic carboxylic acid dianions is reported. The results indicate kinetic and thermodynamic control of silylation of acid dianions.
α‐Cyano‐β‐styrenyl esters for amide bond formation
Authors: Roose B. , Anteunis M. J. O. , Tavernier D.
Published: September 2010

P‐X‐α‐cyano‐β‐styrenyl esters (X = H, Cl, CF3, NO2) of N‐benzyloxycarbonyl valine were prepared. The rate constant for amide formation with methyl valinate was assayed; it increases with increasing electron attracting power of the para substituent. The N‐hydroxysuccinimidoyl ester and the p‐H‐α‐cyano‐β‐styrenyl ester of valine have comparable reactivities.
Structure of 4‐ (N'‐Pivaloyl)‐D‐Phenylalanyl‐L‐Perhydro‐4H‐1,4‐Thiazine‐3‐ (N‐Methyl) Carboxamide in the Crystalline State
Authors: Wu S. , Tinant B. , Declercq J. P. , van Meerssche M. , Borremans F. A. M. , Anteunis M. J. O.
Published: September 2010

C20H29N3O3S, tetragonal, Mr = 391.53, P43212, a = b = 11.688 (1), c = 31.017 (4) Å, Z = 8, Dx = 1.23 g. cm−3, CuKα, λ = 1.5418 Å, μ = 15.17 cm−1, F (000) = 1680, T = 291K, R = 0.055 and RW = 0.061 for 3913 reflections with I ≥ 2.5σ (I) out of 4264 Independent measurements. The peptide chain adopts a conformation of the type II'β turn (ϕ1 = 56°, Ψ1 = −127°, ϕ2 = −93°, Ψ2 = 21°) which is stabilised by an intramolecular H‐bond between the NH of the methylcarboxamide group and the C=O of the pivaloyl moiety. The 4‐thiapipecolic ring has a chair conformation. The torsion angles of the side chain of the Phe residue are χ1 = −179°, χ21 = −80°. The central amide bond is substantially distorted mainly by out‐of‐plane bending of the imino nitrogen (χN = +14°) Thus, conflicting constraints are relaxed, that are imposed by the geometric requirements of the chair form (χ6 = −54°) and of the type II'β turn (ϕ2 ∼ 90°).
Benzylation of Virginiamycin S1
Authors: Sharma N. K. , Anteunis M. J. O.
Published: September 2010

Treatment of Virginiamycin S1 (VS1) with benzyl bromide in the presence of potassium fluoride in DMF at r. t. resulted in quantitative formation of 1′‐N‐Bzl‐VS1 (1) exempt of 1′‐O‐Bzl‐VS1 (2). A 27% conversion of VS1 into 2 however could be achieved by treatment of VS1 with benzyl bromide in DMF at r. t. in the presence of 1, 8‐bis (dimethylamino) naphthalene as the base. The structure of 1 was confirmed by 1D and 2D NMR spectroscopy.
Synthèse Des Pyrazolo [2, 3‐b] Benzotriazepines‐1, 3, 5 A Partir Des Alkyl‐1 Benzodiazepine 1, 5 Ones‐2
Authors: Essassi E. M. , Salem M.
Published: September 2010

The addition of hydrazine to 1‐alkyl 1,5‐benzodiazepine‐2‐thiones yields 1‐(N‐alkyl N‐amino pyrazolyl)‐2‐amino‐benzenes. These compounds react with orthoesters and phosgene to give new heterocycles : pyrazolo 2, 3‐b 1, 3, 5 benzotriazepines.
Quantification of phospholipid phosphorus in sub‐micromolar concentrations
Authors: van Der Meeren P. , Vanderdeelen J. , Baert L.
Published: September 2010

A safe, simple, rapid and very sensitive technique is described for the quantitative estimation of phospholipid phosphorus. In comparison with other procedures, our method is shown to be particularly advantageous for very diluted phospholipid solutions.

The main feature of the method was the acid digestion of large volumes in Kjeldahl flasks. After neutralization, the inorganic phosphate was determined spectrophotometrically.

Using soybean lecithins, both the precision and accuracy of the method were elaborated. The coefficient of variation amounted to at most 1.5% and the sensitivity was reduced to 500 nM of phospholipids.
Simultaneous Use of N‐Fmoc and OTmse Protective Groups in the Synthesis of Peptolytic Sensitive Peptides
Authors: Vanfleteren L. , Anteunis M. J. O.
Published: September 2010

The combined use of Fmoc (fluorenylmethoxycarbonyl) as N‐protection and Tmse (trimethylsilylethyl) as O‐protection during demanding fragment condensation mediated by Bop‐Cl (N, N′‐bis(3‐oxo‐2‐oxazolidinyl)phosphinyl chloride) has been explored in the preparation of useful synthons that are sensitive to acidic and even basic hydrolyses. Stepwise deprotection by morfoline (Fmoc‐deprotection) followed by F⊖‐mediated removal of Tmse results in a very effective peptide synthesis strategy, as exemplified by the preparation of i. a. Phg‐MePhe‐Thz. Similarly, combinations of N‐Bc, O‐Tmse peptide esters are also possible that allow the preparation of ⊕H2‐MePhe‐Thz‐OTmse (via Boc‐MePhe‐Thz‐OTmse) without competitive DKP formation.
α,α‐Dichloroaldehydes and α,α‐Dichlorocarboxylic Acids from Long Chain 1‐Alkanols. Improved Chlorination in the System DMF‐CHCl3‐MgCl21
Authors: De Buyck L. , Casaert F. , De Lepeleire C. , Schamp N.
Published: September 2010

Production of α,α‐dichloroaldehydes by direct chlorination of 1‐alkanols with chlorine gas, catalyzed by DMF and DMF. HCl, was extended to long chain compounds (CnH2n+1OH; n = 5,6,8,10,12,14,16,18). Two problems specific to the longer chains were solved to obtain isolated yields in the range 70‐85%; a) parasitic radical chlorination was largely controlled by shielding from light; b) alkyl alkanoate side product (8% for n=8 but ˜ 25% for n=16 or 18) was decreased to 0‐2% in the presence of MgCl2.H2O. Homogeneity of the reaction medium was improved with chloroform as a cosolvent.

Oxidation of the aldehydes to dichlorocarboxylic acids proceeded smoothly with aqueous KMnO4up to the tetradecanal. For the longer chains 30% hydrogen peroxide‐NaHCO3in acetone (overnight at 48‐52°C) was the preferred oxidant.
Complexation of neutral guest molecules by synthetic macroheterocyclic hosts
Authors: Reinhoudt David N. , Den Hertog Herman J.
Published: September 2010

Macroheterocyclic molecules can be used to organize the binding sites required for selective molecular recognition and/or molecular catalysis. Although most work in the literature deals with recognition of ionic species, there is an increasing interest in the selective complexation of neutral molecules. Based on X‐ray analysis of solid complexes and NMR in solution, hydrogen bonding of host to guest and/or vice versa determines the structure, and very likely also the stability of these complexes between neutral host and guests. This paper describes an NMR method to determine the (weak) association constants of such complexes. Subsequently, two strategies are described for the enhancement of the thermodynamic stability, viz. the introduction of (intraannular) acidic groups in the molecular cavity and the use of metallomacrocyclic hosts in which a ‘soft’ cavity is combined with a ‘hard’ macrocyclic moiety. For both approaches novel synthetic methodology has been designed and for the first approach, the pKa values of acidic groups present in molecular cavities have been studied. Finally we have used the novel metallomacrocycles to organize two (or more) different metal centres in molecular cavities.
Large scale preparation of versatile chiral auxiliaries derived from (S)‐proline1
Authors: Enders Dieter , Kipphardt Helmut , Gerdes Peter , Breña‐Valle Leonardo J. , Bhushan Vidya
Published: September 2010

The synthesis of a variety of enantiomerically pure chiral auxiliaries based on (S)‐proline and bearing sterically demanding side chains at the pyrrolidine moiety, such as the secondary amines (S)‐3,5 and 7 and the hydrazines (S)‐6, is described on a molar scale. As key step, the Grignard or RLi addition to the N‐benzylated proline ester (S)‐1 is used.
Ring opening of 2,2,4,6,6‐pentachloro‐4‐fenyldimedone affording an α,α‐dichloro‐γ‐butyrolactone
Authors: De Buyck L. , De Pooter H. , Schamp N.
Published: September 2010

An α, α‐Dichloro‐γ‐butyrolactone 4 was formed after ring opening of 2,2,4,6,6‐pentachloro‐4‐fenyldimedone with NaOAc‐HOAc in aqueous dioxane. The ring opening in methanol gave a δ‐ketoester 5 which was cyclised with Na2CO3 to afford the cyclic enol ether 6.
Fundamental questions about entropy IV. The hydrophobicity of alkanes: A nearly pure entropic effect
Authors: Huyskens P. L. , Siegel G. G.
Published: September 2010

The low solubility of low‐molecular weight alkanes in water is not due to the necessity of breaking H‐bonds in water upon introducing the solute. It is also not due to the breaking of a special kind of cohesion forces “hydrophobic interactions” in the organic liquid. Experimental evidences are given demonstrating that the hydrophobic effect of water and alcohols with respect to liquid alkanes is nearly purely entropic. The introduction of the alkane has practically no influence on the fraction γ but extends the standardized domain  of one molecule of the hydrogen bonded liquid. The hydrophobic effect is essentially due to this extension of the territory of the mobile order. To a good approximation the increase of the chemical potential of the alkane caused by this effect is given by μHB = ‐nAT(∂ΔS̄A mobile order/∂nB). On the other hand, contrary to the assumptions of multicomponent theories, the combinatorial entropy of the mixture is practically not affected by the presence of the H‐bonds. From the value of the combinatorial entropy derived in part two, and neglecting all enthalpic effects one derives an equation predicting the solubilities of alkanes in water (in volume fractions) ϕB = exp (0.5(V̄B/18‐1) + 0.5lnV̄B/18 ‐ 2V̄B/18). This equation, that does not contain any adjustable parameter, predicts the solubility of all the alkanes within 50% error in a domain which varies from 10−4 to 10−7 volume fraction.
Molecular orbital calculations on oxygen deficient YBa2Cu3O7−x clusters
Authors: D'Heer J. , Hoste S. , van Der Kelen G. P.
Published: September 2010

We have carried out semiempirical molecular orbital calculations (charge iterative EHMO) on different clusters representing YBa2CU3O7‐x. (O < x <1). Charges on the various atoms suggest transport of charge occurs in the CuO2−planes, rather than in the CuO‐chains. The Fermi level energy is found to increase with x. Strong d‐states about 10 eV above the Fermi level are found. Analysis of the highest occupied orbitals shows the importance of Cu 3dx2 ‐ y2 and O 2px, 2py orbitals.
Synthesis, characterization and antitumour activity of a series of diorganotin(IV) compounds of the type Bu2Sn(O‐X‐Y‐O)
Authors: Gieien Marcel , Vanbellinghen Christel , Gelan Jan , Willem Rudolph
Published: September 2010

The synthesis and characterization of a series of diorganotin(IV) derivatives of bifunctional phenol‐alcohols, hydroxyacids and acid‐phenols are described. They exhibitin vitrocytostatic properties against P388 and L1210 leukemiae.
Structure Géométrique Et Électronique De Trois Dérivés Analogues Du Butanedinitrile‐1,4
Authors: Tinant B. , Parfonry A. , Declercq J. P.
Published: September 2010

From X‐ray measurements at 155K, the electronic deformation densities for 1,1,2,2‐ethanetetracarbonitrile(1) and meso 2,3‐dimethyl‐2,3‐bis(p‐cyanophenyl)‐1,4‐butanedinitrile(2) have been obtained by multipolar refinement. Comparison of the maps does not show any indication of substitution effects. The X‐X deformation maps obtained for 2,3‐dimethyl‐2,3‐diphenyl‐1,4‐butanedinitrile(3) show an orientational disorder with a very weak occupation of the second orientation. This explains the abnormal bond lengths that were observed at room temperature.
A five parameter factorial analysis for copper deposition on a platinum rotating disc electrode in galvanic solutions
Authors: Mertens M. , Temmerman E. , Verbeek F.
Published: September 2010

A cyclic voltammetric stripping technique is used to analyse the influence of five parameters on the copper deposition at a rotating platinum ring‐disc electrode. The impact of two pretreatment methods, carbon and electrolytic, and the concentration variations of sulphuric acid, copper sulphate and chloride ions are evaluated in a factorial analysis using the Yates algorithm. Extra information is gathered by electrogravimetric and X‐ray diffraction techniques. The most significant single factors are the copper sulphate and chloride ion concentrations. Carbon treatment with sulphuric acid concentration and electrolytic pretreatment with copper sulphate concentration are important hybrid factors, i. e. with mutual influence.
Synthèse D'α‐(Arylamino)Benzylphosphonates De Bis‐β'‐Chloréthyle
Authors: Smolders Robert René , Brunin Dominique , Sarto Frédéric
Published: September 2010

Bis‐(β′‐chlorethyl)‐α‐(arylamino)benzylphosphonates, potential antitumor agents, have been synthetised by reaction between bis‐(β‐chlorethyl)phosphonate and four N‐benzylidenenaphtylamines or the 4‐[γ‐(methoxycarbonyl)propyl]‐N‐{ p‐[bis‐(β′‐chlorethyl)amino]}benzylideneaniline.
1,4,5,8‐Tetra‐Azaphenanthrene Complexes of Copper(I) and Silver(I)
Authors: Nasielski J. , Nasielski‐Hinkens R. , Heilporn S. , Rypens C. , Declercq J. P.
Published: September 2010

Cu(l) and Ag(l) complexes of 1,4,5,8‐tetra‐azaphenanthrene (TAP) and of two of its methylated derivatives (3,6‐dimethyl‐ and 2,3,6,7‐tetramethyl‐) have been made and characterized. Their HNMR spectra are discussed. The structure of the complex Ag(TAP)2(NO3), as determined by X‐Ray crystallography, is that of a strongly folded and twisted square planar arrangement of the chelating ligands around the silver atom; the four Ag‐N bonds are not equal: they are shorter (2.36 Å) in one pair oftransbonds than in the other (2.56 Å). 3,6‐Dimethyl‐1,4,5,8‐tetra‐azaphenanthrene (3,6dmTAP), a new TAP derivative, has been synthesized starting from 2‐hydroxy‐3‐methylquinoxaline which was nitrated, then treated with POCl3, the resulting 2‐chloro‐3‐methyl‐6‐nitroquinoxaline reacted with hydrazine and the hydrazino group oxidized to give 3‐methyl‐6‐nitroquinoxaline. This was aminated with hydroxylamine, reduced to the diamine and finally condensed with glyoxal to give 2,6‐dimethyl‐ and 3,6‐dimethyl‐1,4,5,8‐tetra‐azaphenanthrene.
The effect of anchoring substitution on the course of a cation olefin bicyclization. Crystal structure of (±)‐(2R, 3′R,5′S)‐2‐(3′‐tert‐Butyl‐5‐Isopropl‐5′‐Methyl‐1′‐Cyclopentenyl)‐1‐Cyclopentanone
Authors: Missiaen Patrick , De Clercq Pierre J. , van Meervelt Luc , King Geoffrey S. D.
Published: September 2010

The SnCl4−induced cyclization of aldehyde (Z)‐1 gives rise to a bicyclic alcohol in high yield, the rearranged structure of which was assigned via X‐ray diffraction of its oxidation product 2. The structure (C18H30O, P21/c, a = 11.253(1), b = 6.990(1), c = 22.260(4)Å, β = 78.17(2)°; Dm = 1.02(1) g. cm3, Dc (Z=4) = 1.017 g. cm−3) has been solved by direct methods and refined to a final R value of 0.086 for 1014 observed reflections.
Comparaison de L'Action Inhibitrice de Certains Halogènométhanes Sur la Propagation des Flammes
Authors: Da Cruz F. N. , Vandooren J. , van Tiggelen P.
Published: September 2010

This systematic study is focused on the influence of the addition of several halogenated fluorocarbon compounds (CF4, CF3H, CF3Cl, CF3Br, CF2Cl2, CFCl3) on the burning velocities and final temperatures of stoichiometric CO/O2/Ar/H2 flames. The inhibiting strength decreases along the sequence CF3Br > CFCl3 > CF2Cl2 > CF3Cl > CF3H > CF4 Moreover, the inhibition effect is more pronounced for CO/O2/Ar flames either containing low quantities of H2, or in lean mixtures.

The competition between the reaction of the inhibitor scavenging hydrogen atoms and the branching reaction (H + O2 → OH + O) is the main process for inhibition. The rate constants and the activation energy of the individual trapping reactions of the inhibitor must be in between specified limits. The efficiency of the inhibitor is closely related to the rate constants and the activation energy of the primary trapping process. Nevertheless, the occurrence of Br or Cl atoms in the inhibition molecule enhanced the inhibition effect by subsequent scavenging reactions.
Lead tetraacetate oxidation of (Z)‐ and (E)‐5, 10‐Secocholest‐1 (10)‐ENE‐3β,5α−Diol 3‐acetate1
Authors: Mihailović Mihailo Lj. , Kruščić Natalija , Pavlović Vladimir , Lorenc Ljubinka
Published: September 2010

The lead tetraacetate oxidation of (Z)‐5, 10‐secocholest‐1(10)‐ene‐3β,5α−diol 3‐acetate (1) gave products arising from: (i) conversion of the 5α−hydroxy group to the ketone function (2), (ii) intramolecular cyclization (to the 2α,5α−tetrahydrofurane‐type ether 3), and (iii) allylic acetoxylation at the C(9) position (3 and 4), while similar oxidation of (E)‐5, 10‐secocholest‐1 (10)‐ene‐3β,5α−diol 3‐acetate (5) afforded mainly the product formed by conversion of 5α−OH to the keto‐carbonyl group (6).
1‐Organo‐4,4‐Dimethyl‐1,4‐Phosphastanninanes
Authors: Weichmann H. , Rensch B. , Dargatz M. , Meunier‐Piret J.
Published: September 2010

The title compounds Me2Sn(CH2‐CH2)2PR (1:R=Ph;2:R=t‐Bu) were prepared by hydrostannation of (CH2=CH)2PR with Me2SnH2. Oxidation with chalcogenes and reaction with Mel yields the corresponding P‐derivatives Me2Sn(CH2‐CH2)2P(X)R (3 ‐ 7:X=O, S, Se) and Me2Sn(CH2‐CH2®2Pr̀ MePh I−(8). NMR data (1H, 13C, 119Sn, 31P) suggest for 1 ‐ 8 a rigid chair conformation with the P‐substituent R being equatorially orientated. This conclusion was confirmed by the X‐ray analysis of 3 which revealed that the chair is flattened at the tin segment and puckered at the phosphorus part of the ring.
Isocyanates Bloques: Etude Cinetique Et Thermodynamique
Authors: De Aguirre I. , Collot J.
Published: September 2010

A kinetic and thermodynamic study of the deblocking of urethanes is presented; the blocking agents are phenols, aliphatic alcohols and a polyether. The deblocking occurs via the elimination‐addition mechanism. In the transamination reaction, the rate determining step is the amine catalyzed dissociation of the blocked isocyanate. The equilibrium constants of these reactions give the relative stability of blocked isocyanates. The dissociation equilibrium of several urethanes were also determined; temperature higher than 170°C are required to obtain a significant dissociation in the case of usual urethanes.
Enantioselective Catalysis, 471Rhodium(II)‐Carboxylate Complexes and Their Use In the Enantioselective Cyclopropanation
Authors: Brunner H. , Kluschanzoff H. , Wutz K.
Published: September 2010

13 optically active complexes of the type Rh2(OOCR*)4were synthesised, derived from optically active carboxylic acids R* COOH. The new rhodium(II) complexes were used as homogeneous catalysts for the cyclopropanation of styrene with ethyl diazoacetate. The product ethyl cis/trans‐2‐phenylcyclopropanecarboxylate was obtained with an optical induction up to 12 %ee.
Calculation of the Protonation Constants of Secondary N‐Chloramines
Authors: Antelo Juan M. , Arce Florencio , Franco Julia , Sanchez María , Varela Angel
Published: September 2010

Spectrophotometric determinations of the pK of six secondary N‐chloramines have been used to obtain an empirical equation relating the pK of secondary N‐chloramines to those of the corresponding amines.
1H NMR and 13C NMR Study of Two Vincristine Derivatives at 300 Mhz
Authors: Bhushana Rao K. S. P. , De Bruyn André , Trouet André , Verzele Maurice , Hannart Jean
Published: September 2010

13C, 1H heteronuclear shift correlated experiments allow to assign for the first time the 1H and 13C NMR parameters of 2 vincristine derivatives.
Oxidation of 2‐[2‐(3,4‐Dimethoxybenzylhydroxymethyl)‐4,5‐Dimethoxyphenyl]Ethanol Using Chromium (VI) Reagents
Authors: Domínguez E. , Iriondo C. , Laborra C. , Linaza A. , Martínez J.
Published: September 2010

The oxidation reaction of the title compound by means of chromium (VI) reagents afforded, not the expected dicarbonyl derivative, but cyclization compounds. Their structures determined on the basis of their spectral data are reported.
Synthesis, Physical Studies and Vibrational Spectra of the NI(II), Pd(II) and Cu(II) Complexes of N‐(2‐Aminoethyl)‐ and N‐(3‐Aminopropyl)Oxamide
Authors: Periepes Spiros P. , Quaeyhaegens Frank , Desseyn Herman O.
Published: September 2010

The new complexes K2[Ni(aeo)2]H2O, K2[Cu(aeo)2]·H2O, K2[Cu(aeo)2]·H2, K2[Ni(apo)2]·H2O, K2[Cu(apo)2]‐·2H2O, K2[Cu(apo)2·2H2O, K2[Pd(apo)2·2H2O and [Pd(Hapo)Cl]·0.5H2O, where H2aeo=N‐(2‐amino‐ethyl)oxamide and H2apo=N‐(3‐aminopropyl)oxamide, have been prepared. Several synthetic routes were investigated. The complexes were characterized by analyses, conductivity measurements, X‐ray diffraction, thermogravimetry, magnetic susceptibility measurements and spectral (IR and far‐IR, ligand field, ESR) studies. Monomeric square planar structures are assigned in the solid state for the [M(aeo)2]2− and [M(apo)2]2− anions in the complexes K2[Ni(aeo)2]H2O, K2[Cu(aeo)2]H2O (for both the rose and violet forms), K2[Ni(apo)2]H2O, K2[Cu(apo)2]·2H2O (rose form) and [Pd(Hapo)Cl]·0.5H2O; the doubly deprotonated aeo2 and apo2 ions exhibit a bidentate N(secondary amide), N′(tertiary amide)‐coordination with the ‐NH2 group remaining uncoordinated. Anionic oligomeric or polymeric elongated rhombic and distorted octahedral stereochemistries are proposed for the compounds K2[Cu(aeo)2]·H2O (green form) and K2[Cu(apo)2]·2H2O (royal blue form), respectively. The deprotonated CONH− group of Hapo− is coordinated to different Pd(II) atoms in [Pd(Hapo)Cl]·0.5H2O through both its nitrogen and oxygen atoms. The vibrational analysis of the monomeric complexes is given using NH/ND, NH2/ND2, 58Ni/62Ni and 63Cu/65Cu substitution.
Electrochemical Studies of Europium(III) in Potassium Sulfate Medium: The ko and α Values
Authors: Lopez V.
Published: September 2010

Polarographic investigation of Eu(III)‐SO42− in aqueous solutions have been carried out with a dropping mercury electrode.

The complex species in solution and the kinetic parameters ko and α of this system have been determined. The electrochemical behaviour depends on the SO42− concentration and pH.
Coordinative Properties Study and Preparation of a Resin Containing Polystyrene and Thiourea
Authors: Schmidt Ricardo , Förster Juan E. , Moya Sergio A.
Published: September 2010

A matrix formed by reaction of styrene‐divinylbenzene copolymer with thiourea has been prepared and studied. The thiourea is covalently bound to the polymer matrix through the sulfur atom. The properties of the prepared resin have been studied with respect to the uptake of some ionic species such as: Cu(II), Zn(II), Fe(III), Au(III), Re(VII) and As(III).
The Michael Type Additions of Tetrazole Derivatives to Double and Triple Carbon‐Carbon Bonds
Authors: Dziklinska H. , Dzierzgowski S. , Jezewski A. , Plenkiewicz J.
Published: September 2010

The reactions of 5‐substituted tetrazoles, 1‐substituted tetrazolin‐5‐ones, and 5‐substituted 1‐hydroxytetrazoles with ethylene derivatives possessing electron withdrawing substituents were found to be of practical value in preparing variously substituted tetrazoles. 1‐Hydroxy‐5‐substituted tetrazoles, when treated with acetylene dicarboxylates, yield a mixture of (E) and (Z) isomers of Michael type addition product, which decomposes subsequently affording 2‐(2‐tetrazolyl)acetates. The formation of the latter corresponds with formal breaking of carbon‐carbon triple bond.
Determination Voltamperometrique D'Iodures A L'Aide D'Une Electrode Tournante a Renouvellement Constant De La Surface
Authors: Stoytcheva Margarita , Noninski Christo
Published: September 2010

Des études ont été effectuées sur 1′emploi d'une électrode tournante à renouvellement constant de la surface pour des analyses dans le domaine de potentiels positifs. La reproductibilité des résultats et 1′influence de différents facteurs‐vitesse de renouvellement de la surface de l'electrode, concentration du dépolarisant, nature de l'électrolyte indifférent, sur le courant de diffusion et le potentiel de demi‐vague lors de l'oxydation des iodures, ont été déterminées. On a trouvé que les courbes voltammétriques, sans oscillations et d'une parfaite reproductibilité, rendent la méthode propre pour la détermination qualitative et quantitative des iodures.
Synthesis of Two New Metal Ion Sequestering Agents: 1,4‐Diaza‐7‐Thiacyclononane‐N,N′‐Diacetic Acid and of 1,5‐Diaza‐8‐Thiacyclodecane‐N,N′‐Diacetic Acid
Authors: Wambeke D. M. , Lippens W. , Herman G. G. , Goeminne A. M.
Published: September 2010

The synthesis of two new multidentate metal ion sequestering agents, 1,4‐diaza‐7‐thiacyclononane‐N,N′‐diacetic acid (III) and 1,5‐diaza‐8‐thiacyclodecane‐N,N′‐diacetic acid (VI), using the Richman‐Atkins procedure and subsequent derivatisation with ethyl bromoacetate is described.
Podands Based on 1,4,5,8‐Tetra‐Azaphenanthrene and Their Complexation With Ru2+
Authors: Nasielski J. , Chao S.‐H. , Nasielski‐Hinkens R.
Published: September 2010

Summary. New podands, based on 1,4,5,8‐tetra‐azaphenanthrene, have been synthesized from 2‐chloro‐1,4,5,8‐tetra‐azaphenanthrene 3; when the anchoring group is a nitrogen atom, the corresponding podands are, however, unstable. When reacted with Ru2+in an ionizing solvent, podands tris(2‐(2‐(1,4,5,8‐tetra‐azaphenanthryloxy))ethyl)methane 4c and tri(2‐(2‐(1,4,5,8‐tetra‐azaphenanthryloxy))ethyl)trimesoate 9 give only polymeric complexes; in chloroform, complexation stops at bis‐chelation, giving two types of structures. The most intriguing is the twisted type (12, 13) where one of the chelating group has been inverted, giving rise to an unprecedented flattened Ru2+octahedron.
Réduction Asymétrique D'Allylamines Et Dérivés a L'aide De Complexés Du Rhodium
Authors: Fahrang Roya , Sinou Denis
Published: September 2010

Prochiral allylic amines are reduced as their chlorhydrates using rhodium complexes of various 1.2‐, 1.3‐ and 1.4‐diphosphinocompounds with enantiomeric excess (e.e.) up to 60%. The N‐acetyl derivatives of the allylic amines are reduced with low e.e.
A Novel Rearranged Abietane Diterpene From Coleus barbatus
Authors: Kelecom Alphonse , Medeiros Walter L.B.
Published: September 2010

The new diterpene 9(10→20)‐abeo‐abieta‐8,11,13‐trien‐10β,11,12‐triol (1), has been isolated from the stems of Coleus barbatus Bentham and its structure determined from spectral data and hemisynthesis.
The Application of DSC in the Physico‐Chemical Characterization of Transparent Oil‐Water Gels
Authors: Christine Provost
Published: September 2010

Transparent oil‐water gels formed in a four‐componentsystem composed of two nonionic emulsifying agents, Cetiol(R) HE and Eumulgin(R) B3, of an oily liquid, isopropyl palmitate, and of water were investigated by differential scanning calorimetry. A comparison was made with the thermal behaviour of their separate components and of some of their binary and ternary mixtures. The results show that DSC can supply information concerning some elements controlling the formation of transparent oil‐water gels. These elements include the hydration of the emulsifiers, various intercomponent interactions, and the nature of the binding forces in the gel structure. DSC thus contributes to clarifying the mechanisms behind this gelformation.
A Search For Phenolic Protection in Virginiamycin S
Authors: Sharma N. K. , Anteunis M. J. O.
Published: September 2010

In order to be able to mask the hydroxyl grouping of the pipecolic acid residue in Virginiamycin during alkaline (NaOH) and acidic (Tfa) break‐down procedures and to use peptidic fragments coming thereof for further reconstitution by classical peptide synthesis procedures, we have investigated several candidates for protection/deprotection. Thus the phenacyl derivatives (4 & 5), the allyloxycarbonyl derivative (6), the trichloroethyloxycarbonyl derivatives (8 & 9) and the 2,4‐dinitrophenyl derivative (10) have been prepared. Among these none were stable in aqueous basic conditions. The Alloc‐ (6) the Troc (8) and Dnp‐derivative (10) may have some applications under acidic conditions.
Behaviour of Cyclopropanes Bearing Capto‐Dative Substitution Upon Electron‐Impact and Flash‐Vacuum Pyrolysis Conditions
Authors: Chen Lin‐Zhi , Flammang Robert , Maquestiau André , Masamba Wayiza , Merényi Robert , Pommelet Jean‐Claude , Viehe Heinz‐G.
Published: September 2010

Tandem mass spectrometry has been applied to investigate the behaviour of bis‐captodative (cd) substituted cyclopropanes NC(SR)CCH2C(SR)CN [1, R=CH3; 2, R=tBu and 3, R=C6H5] upon electron impact (EI) and flash‐vacuum pyrolysis (FVP) conditions. Ring‐opening of the molecular ions of 1 followed by a 1,2‐hydrogen shift preceedes the fragmentation consisting mainly in the competitive losses of CH3S and CH2S. The least energy demanding reaction is however a methyl loss requiring also ring cleavage. The m/z 70 base peak is ascribed to cyanothioacylium ions (N=C‐=S) as indicated by the characteristic fragmentations induced by collision. Upon FVP conditions 1decays to the cd olefin 8 and the carbene 9 in competition with the extrusion of CH3S. and CH3. radicals at the highest temperatures. The behaviour of 2 upon both conditions is dominated by the chemistry of the t‐butyl substituents.

Ring cleavage of the molecular ions of 3 preceedes also the fragmentation and induces rearrangement reactions yielding unexpected cyclohexadiene thione ions and C7H7+ ions. Upon FVP, C‐S bond homolysis readily occurs in competition with an elimination of a carbene molecule.
Recherche Des Sites D'Association Privilégiés Dans Des Molécules Polyfonctionnelles Par Rmn Du Carbone‐13
Authors: Seguin J. P. , Goethals G. , Moreau‐Descoing M. C. , Sarazin C. , Doucet J. P.
Published: September 2010

The carbon chemical shifts induced by hydrogen bonding have been measured for complexes between acetophenone and various alcohols. Linear relationships are obtained between corrected induced chemical shifts and the IR frequency shifts Δν. For carbonyl and C‐4 carbons, positive slopes are observed but a reverse effect results for C‐1 carbon. The hydrogen bond effects on carbon shifts of γ‐acetylpyridine are compared with those obtained for pyridine and acetophenone and we can conclude that the preferential association site for this polyfunctional compound is the nitrogen atom.
Polymères Thermostables: Thermoplastiques Et Thermodurcissables, Nouvelles Tendances
Authors: Sillion Bernard
Published: September 2010

This paper deals with the recent developments and the trends in the field of the heat resistant linear and thermosetting polymers.

Two driving forces can explain the recent important efforts of research and development. The first target is the improvement of the processability for these materials and the second one is the strong demand for heat resistant macromolecules with specific properties such as low thermal expansion coefficient, low loss factor, low permittivity, improved toughness…

Three types of material will be discussed in this paper: the linear polymers, the thermosetting resins and the semi‐interpenetrated networks (semi IPN's).

The heat resistant linear polymers are generally amorphous, their high viscosities above the glass transition (Tg) limits the processability and the rather low Tg does not allow the high temperature application. In order to solve these problems, three main approaches have been studied. First the crystalline polyimides were prepared by introducing ether ketone sequences in the main chain so the high temperature properties are governed by the crystalline transitions. The second approach is the development of amorphous fully cyclized polymers exhibiting high Tg. These polymers were obtained with bulky or fluorinated group in the backbone. Finally a new concept is now developed, it is based on an intramolecular thermal rearrangement occuring in a flexible main chain and leading to a rigid one.

Concerning the heat resistant thermosetting resins, the following problems have to be solved: the low solubility of this type of telechelic oligomers, their high melting point and, as a consequence, the very narrow processability window and the brittle character of the final network. For these purposes, the bis‐maleimide were crosslinked with allylic resins, a new soluble precyclized nadimide resin was developed and a new concept of redox reaction for the formation of phthalocyanine network was discovered.

Very promising seems the semi IPN's networks in the field of the heat resistant polymers. Starting from the same diamine for the preparation of linear and thermosetting resins (bis‐maleimides and end‐capped acetylenic resins) allows a good miscibility of the mixture of linear and thermoset before curing.

After crosslinking a phase segregation occurs. Good mechanical properties are observed above the Tg of the linear polyimide. The thermal stability of the semi‐IPN is strongly dependent on the nature of the thermosetting resins, so the semi‐IPN's with acetylenic are more thermostable than the semi IPN's with bis‐maleimide.
Relations Entre Structure Chimique Et Propriétés Mécaniques Dans Les Réseaux Époxydes
Authors: Halary Jean‐Louis , Cukierman Serge , Monnerie Lucien
Published: September 2010

Relationships existing between chemical structure and the dynamic mechanical properties of epoxide networks are reviewed. This paper is focused on different model networks, prepared by the reaction between amines and DGEBA or DGEBD diepoxide monomers in stoichiometric proportions. The limit glass transition temperature, Tg∞, is shown to depend mainly on molecular flexibility of network chains and on crosslink density. Frequency dependence of Tg∞ obeys the time‐temperature superposition principle and can be described by a WLF‐type equation. However, the coefficients C1 and C2 in this equation depend on the molecular characteristics of the network, in agreement with free volume concepts. Values of elastic modulus well above Tg reflect mostly the influence of crosslink density. Surprisingly to some extent, application of rubber elasticity theory to these densely crosslinked systems yields very reasonable average network chain molecular weights Mc. In the glassy region, the mechanical relaxations β and γ are shown to originate from motions of ‐CH2‐CHOH‐CH2‐O‐ epoxide groups and of ‐(CH2)4‐ groups, respectively. Motions responsible for the β‐relaxation appear at the same temperature, whatever the network characteristics may be. On the other hand, both amplitude and broadening of the β‐relaxation loss peak are functions of crosslink density. From a practical viewpoint, these two characteristics influence markedly the plastic behavior of the networks and their elastic modulus at room temperature as well.
Polydichlorophosphazenes: Synthèse à Partir De Cl3Pnp(O)Cl2
Authors: D'Halluin G. , De Jaeger R. , Potin PH.
Published: September 2010

The polychlorophosphazenes of the general formula

This alternate synthetic method is detailed. The course of this polycondensation has been investigated by 31P NMR spectroscopy (400 MHz).

The assignments of all the 31P NMR signals of digomers have been performed. Knowledge of these 31P NMR properties leads to the understanding of the detailed mechanism of the polycondensation through the quantitative analysis of several intermediate species involved in the reaction.

The major impurities formed during the synthesis of Cl3PHP(O)Cl2 have been identified. Their catalytic or inhibitant effect has been studied.

The results obtained lead the prediction of an industrial exploitation of this process.
Solvent‐Extraction Behaviour of Nickel (II) With Lauric Acid
Authors: Hurtado Selva N.
Published: September 2010

The extraction of Ni(II) using lauric acid dissolved in toluene was carried out in the pH 5‐7 range. The influence of the acetate ions on extraction percentage and stoichiometry of the extracted species was studied and it was shown that they do not affect the range of concentrations examined, namely, from 0.1 M to 1 M. The extraction percentages of Ni (II) were considerably upgraded by the addition of 1–10 phenanthroline hydrochlorate. The optimum concentration of 1‐10 phenanthroline hydrochlorate/nickel (II) was found to be equal to 1.5.

Finally, a description is given of the stripping processes for Ni (II) with sulphuric acid from organic phases obtained by extraction with lauric acid in aqueous solutions of Ni (II) either free or forming complexes with the 1‐10 phenanthroline hydrochlorate.
The Configuration of Palustrol and Related Compounds
Authors: Braekman Jean‐Claude , Daloze Désiré , Stoller Catherine , Declercq Jean‐Paul
Published: September 2010

The structure of diol 5, an autoxidation product of (+)‐palustrol, has been determined by X‐ray diffraction analysis. From these data, the relative and absolute configurations of (+)‐palustrol and of several related aromadendrane derivatives could be established.
Synthesis of 2′,3′‐Disubstituted 3′‐Deoxythymidine Derivatives
Authors: Herdewijn P. , van Aerschot A.
Published: September 2010

Reaction of 2 with DAST followed by detritylation and monomethoxytritylation afforded 34% of the fluorinated nucleoside 3. This intermediate was used to prepare the 3′‐azido‐2′‐fluoro‐and 2′,3′‐difluoro substituted 5‐methyluridine analogues 7 and 11, respectively.
Le Diethylacetal Du Cyano‐3 Propene‐2 Al Comme Equivalent Synthetique D'Heterocumulenes Fonctionnels
Authors: Lassalle Gilbert , Grée René
Published: September 2010

The easy transformation of pyrrolidine 4 in 5 and then into 7 shows that the diethylacetal of 3‐cyano 2‐propenal can be considered as a useful synthetic equivalent of the functionnalized heterocumulenes 2 and 3.
The Synthesis, Vibrational Spectra and Thermal Analysis of Different PD(II) Polymers with Planar Dithiooxamides
Authors: Bellaihou M. , Weyten H. , Desseyn H. O.
Published: September 2010

Different polymeric complexes of Pd(II) with planar dithiooxamides have been synthesized. The infrared spectra and the thermal analysis of these new compounds are discussed.
Solvent ‐ Extraction of Ag(I) and CD(II) with Rosin
Authors: Selva N. Hurtado
Published: September 2010

The extraction of Ag(I) and Cd(II) cations from their respective aqueous solutions with rosin dissolved in toluene has been studied. In both cases yields close to 100% were obtained in one single stage. At the same time, the influence on the process of pH, ionic force and concentration of the extractant was analysed.

The stripping of each one of the cations in the rosin‐in‐toluene solutions was also carried out, yields of almost 100% being obtained in a single stage in both cases. Stripping of Ag(I) requires very important excesses of sulfuric acid and it was only possible to use stoichiometric amounts of this acid from Ag(I) concentrations of 7 g/l. In the case of Cd(II) concentrations equal or higher than 4.5 g/l of cation are required.

Finally, a separation method for both cations, Ag(I) and Cd(II) was developed on an experimental scale which also makes it possible to obtain stripped aqueous phases wherein the Ag(I) in one of them and the Cd(II) in the other are 25 times more concentrated.
Complexes of Salicylaldehyde Ferrocenylcarbonylhydrazone with Some Metal(II) Ions
Authors: Yong‐Xiang Ma , Zheng‐Zhi Zeng , Hong‐Sui Sun , Guo‐Sheng Huang
Published: September 2010

The complexes of salicylaldehyde ferrocenylcarbonylhydrazone with some metal(II) ions have been prepared. Their elemental analyses and IR spectra show that the hydrazone coordinates to the central ions in the enol form with a 1:1 stoichiometry. The complexes manifest subnormal magnetic moments and the electronic spectra correspond to the square‐planar configuration.
Synthesis and Characterization of New Rhenium (V) Complexes of Tetradentate Schiff Base Ligands
Authors: Amer S. A.
Published: September 2010

Reaction of trichloro‐oxo‐bis (triphenylphosphine) rhenium (V) and Schiff bases derived from some aliphatic diamines and 2‐hydroxy‐1‐naphthaldehyde in the presence of triethylamine gives as anionic complex (ReOLCl2)−, where L is a tetradentate Schiff base ligand. On the basis of various physical properties, the complexes are assigned seven coordinate. The structure of the complex depends on the length of the methylene chain of the ligand. The ReO−3+ complexes form monomeric or polymeric complexes by ligand bridging.
Stéréochimie de (2S, 4S, 5R;2S, 4S, 5S)‐ et (2R, 4S, 5R;2R, 4S, 5S)‐2‐alkyl‐1,3,4‐triméthyl‐5‐phénylimidazolidines déterminée par RMN‐−1H et ‐−13C
Authors: Tytgat D. , Gelbcke M.
Published: September 2010

The condensation of (1R,2S) or (1S, 2S)‐N,N′‐dimethyl‐1‐phenylpropane‐1,2‐diamines with aldehydes gives respectively two diastereomeric 2‐alkyl‐1,3,4‐trimethyl‐5‐phenylimidazolidines. At thermodynamical equilibrium the major isomer in the erythro series is this one where the substituents at position 2 and 4 are ”cis“. In the threo series, the major isomer has the substituents at position 2 and 4 ”trans“.
Synthesis and 2‐D NMR Characterization of New Precursors of Electronically Conducting Polymeric Films: 1‐ and 2‐[2‐(1‐adamantyl)2‐oxo‐ethoxy]‐naphthalenes
Authors: Moustafid T. El , Hedayatullah M. , Seba H. B. , Pigenet C. , Ancian B.
Published: September 2010

The synthesis and 2D NMR (J resolved −13C, −1H and −13C, −1H correlation) characterization of new adamantylated electronically conducting polymer precursors are described.
Nouvelles méthodes de synthèses des dérivés du pyrazole et de l'isoxazole a partir de la phényl‐7 diazépine‐1,4 thione‐5
Authors: Chammache M. , Essassi E. M. , Salem M. , Zniber R.
Published: September 2010

In this work, two new pyrazole and isoxazole derivative have been synthetized from 7‐phenyl‐1,4‐diazepine‐5‐thione. These products have been characterized by −1HNMR, IR, MS and microanalysis.
The N‐Amidinoethylation of 2‐Aminoethanol by Michael Reaction with a N,N′‐Disubstituted Propenamidine
Authors: Fuks Robert , Trémerie Bernadette , Khamlichi Samir , Muller Daniel , Josefonvicz Jacqueline
Published: September 2010

The addition of 2‐aminoethanol 1 to the propenamidine 2 under neutral conditions lead to 1:1‐ and 1:2‐ adducts 3 and 4 by the Michael addition of the amino end‐ group to the C = C double bond of 2.
”In situ“ Silylation with Trimethylsilyl Cyanide an Outstanding Protocol for Fast Peptide Synthesis a Synopsis
Authors: Anteunis M. J. O. , Becu Chr. , Becu Fr.
Published: September 2010

The use of trimethylsilyl cyanide as a potent ”in situ“ silylating agent and its compatibility with most classical functionalities employed during solution phase peptide syntheses allows repetitive peptide chain elongations (including linear Head‐to‐Tail) with a minimum of chemical steps and manipulations. The outstanding features are: the upscaling facilities, the simplicity and the high purity of the final peptides exempt of stereomutation.
A Kinetic study of C3O2/H‐Systems: Rate Constant of the Reactions C3O2 + H, HCCO + H and HCCO + O2 at T = 285 ‐ 566 K
Authors: van De Ven P. , Peeters J.
Published: September 2010

The reaction of C3O2 with H was studied under first order conditions at excess H‐atoms in the temperature region 285‐566K and at a pressure of 2 Torr. The experiments were carried out by means of a discharge‐flow technique combined with molecular‐beam mass spectrometry. The rate constant for

C3O2 + H → HCCO + CO

was found to be

K1 = (1.3±0.2) 10−11 exp 〈(−1320±80)K/T〉 cm3 molec−1s−1

The kinetic coefficients of the subsequent reactions of HCCO with H and O2 were derived using deductive modelling techniques. The experiments were carried out at room temperature. The resulting rate constants obtained (with 95% confidence region) were:

HCCP + H → products

k = 2.0 (1.0−4.0) 10−10 cm3molec−1s−1

HCCO + O2 → products

k = 1.4 (1.0−2.0) 10−12 cm3molec−1s−1
Model Studies Directed Towards Microalga Polyether Toxins
Authors: Alvarez Eleuterio , Díaz Maria Teresa , Zurita Dácil , Zárraga Miguel , Martín Julio D.
Published: September 2010

In view of the described results in acid‐induced polyepoxide cyclizations, the biosynthesis of fused polyether toxins may be better explained by a stepwise mechanism through oxonium ion intermediates acting on the enzyme‐bonded polyepoxide precursor. A new synthetic strategy for the regio‐ and stereospecific synthesis of heterosubstituted oxolane and oxane rings involving intramolecular iodoetherification of 2,3‐epoxy‐cycloalken‐1‐ols was studied. Cyclization/solvolysis of 2,3‐epoxy‐cycloalk‐5‐en‐1‐ols proceed with complete regio‐ and stereoselectivity to yield cis‐2,6‐dialkyl‐3,5‐oxygenated oxane rings and thus assemble in two steps the key structural units present in marine syn‐trans fused polyether toxins. A highly efficient cyclization reaction of 2,3‐epoxycyclonon‐6‐en‐1‐one leading to the oxepane system is described. The silver(I)‐induced solvolysis occurs in high yield under mild conditions and the resulting cyclic system may be manipulated via oxidative carbon‐carbon bond cleavage leading to a functionalized α, α′‐dialkyl β,β′‐oxygenated oxepane ring with defined cis‐syn‐cis stereochemistry.
Enantioselective Catalysis with Metal Complexes Containing Heterocyclic Ligands
Authors: Pfaltz Andreas
Published: September 2010

Chiral C2‐symmetric semicorrins, a class of bidentate nitrogen ligands, are readily prepared in enantiomerically pure form starting either from D‐ or L‐pyroglutamic acid. They possess a number of features that make them attractive ligands for enantioselective control of metal‐catalyzed reactions. (Semicorrinato)copper complexes have been used as efficient catalysts for the enantioselective cyclopropanation of olefins with diazo compounds. Using (semicorrinato)cobalt complexes as catalysts, α,β‐unsaturated carboxylic esters and amides can be enantioselectively reduced with sodium borohydride, giving the corresponding saturated esters and amides with enantiomeric excesses up to 98%.
The Reaction of Quinoxaline‐ and Phenazine‐N‐Oxides with Thionyl Chloride and Paratoluenesulfonyl Chloride
Authors: Nasielski J. , Heilporn S. , Chauveheid E. , Poppe K. , Nasielski‐Hinkens R.
Published: September 2010

2,3‐Diphenylquinoxaline‐N‐oxide 1 with thionyl chloride gives only 5‐chloro‐ and 6‐chloro‐quinoxaline and very little deoxygenation. Phenazine‐N5‐oxide 2, in the same conditions, gives mainly 2‐chlorophenazine and minor amounts of 1‐chlorophenazine, but here deoxygenation is an important pathway. Freshly recrystallized para‐toluenesulfonyl chloride gives a high chlorination‐to‐tosyloxylation ratio. All these results point to a variable ability of acid chlorides to yield homocycle chlorination or acyloxylation; this is confirmed by the observation that phenazine‐N5‐oxide and phosphoryl chloride give fair amounts of aryl phosphate.
Fluorescence studies of the kinetics of processes in polyelectrolyte and ionomer solutions
Authors: Morawetz Herbert
Published: September 2010

(1) A stopped‐flow apparatus with fluorescence detection was employed to follow the expansion of poly(methacrylic acid) (PMA) after a pH‐jump using either a dansyl‐labeled polymer (where emission is quenched by contact of the label with water) or doubly labeled PMA, where the efficiency of nonradiative energy transfer from the donor to the acceptor label decreases with chain expansion. The final approach to conformational equilibrium was found to be unexpectedly slow. (2) The kinetics of the enhancement of the fluorescence of Auramine 0 when it was mixed with the contracted form of PMA was insensitive to the polymer concentration, suggesting that it is due to a conformational transition of the polymer following the adsorption of the dye. (3) Partially ionized polycarboxylic chains carrying a β‐naphthol moiety were used to study the proton transfer from the excited naphthol to ionized carboxyls. The data suggested that the local chain flexibility is independent of the degree of ionization. (4) Solutions of slightly sulfonated polystyrene neutralized with aminomethyl naphthalene and aminomethyl anthracene, respectively, were mixed in the stopped‐flow apparatus and the kinetics of counterion interchange was deduced from the increasing efficiency of nonradiative energy transfer from the naphthalene to the anthracene label. (5) On mixing solutions of methyl methacrylate copolymers with small fractions of 4‐aminostyrene hydrochloride and N,N‐dimethylaminoethyl methacrylate, respectively, the HCl transfer from the aromatic to the aliphatic amine was followed by the increase of fluorescence. Using this model system, it was shown that the rate constant decreases with the length of the chains to which the interacting moieties are attached.