Reaction d'aminomercuration—xv: Aminomercuration d'olefines par les amines aromatiques en milieu aqueux

Aminomercuration of double bond by aromatic amines is easily performed by using an aqueous solvent. No oxymercuratio occurs. The reaction is general, regiospeciflc with terminal olefins. This specific feature of aromatic amines is due to a preliminary ring mercuration whose effect is to destroy the preformed amine/mercuric salt complex preventing the reaction.     

Aminomercuration intramoleculaire d'aziridines cycloocteniques et de leurs aminoalcools precurseurs

N-substituted cyclooctenic aziridines undergo intramolecular mercuration with mercuric salts; after reduction, N-substituted 9-azabicyclo[3.3.1]- and [4.2.1]nonanes are isolated. Mercuration of amino alcohols (precursors to aziridines) leads to the same products but with different yields dependent on the mercuric salt used. In some cases, aziridinium salts are intermediates in basic medium from the organo mercuric compounds during reduction. Extension of this reaction is studied with two aliphatic models.     

Hétérocyclisations intramoléculaires par réaction d'oxymercuration III. Régiosélectivité et stéréosélectivité de l'oxymercuration intramoléculaire de phénols orthoallyliques

The intramolecular heterocylization of ortho-allylic phenols by oxymercuration has been realized with compounds having different substituents on the allylic chain. In all cases, only the corresponding benzofuran is formed. However, with a substituent at the terminal carbon of the double bond, we also observed the formation of benzopyran. The influence of the solvent and the mercuric salt on the orientation of this reaction has been examined. There is evidence of a molecular rearrangement during the reduction.     

Sels d'alkyloxyphosphonium—XVI: Activation de l'hydroxyle anomere des 2,3,4,6 tetra-o-acyl-d-mannopyranoses

The joint action of tris(dimethylamino)phosphine-carbon tetrachloride on a tetra-O-acyl-2,3,4,6-d-mannopyranose leads to one α anomeric oxyphosphonium chloride (ATDP salt). This salt is not isolable, but decomposes to yield an anomeric mixture of 1-chloro derivatives. The reaction with alcohols give rise to the formation of orthoesters while thiophenol reacts to yield only the β-thiomannoside. These results are discussed and interpreted.     

Stereochimie et mecanisme de l'ouverture par les amines d'ions N-alcoxypyridinium : Formation competitive d'un ylure endocyclique; application a une nouvelle conversion heterocyclique

The N-alkoxypyridinium salt 1, with pyrrolidine, piperidine and diethylamine, undergoes reversible ring opening in acetonitrile. This competes with irreversible cyclization of an ylide to the bicyclic intermediate 3 which suffers subsequent ring opening to 3-ω-aminobutadienylisoxazol-4 ones in methanol. The different courses of the reaction is tentantively explained by means of HSAB theory. Stereochemistry of the primary open products is consistent with a disrotatory ring opening of cis-dihydropyridine adducts resulting from amine addition to the salt 1 or to the bicyclic ion 3. These primary products are further isomerized and all-trans structures have been isolated in the case of isoxazoline derivatives. Conversion of an N-alkoxypyridinium salt to substituted butadienylisoxazolones exemplifies a new type of heterocyclic ring transformation that can be described by the PARC-ANRO sequence: Proton Abstraction, Ring Closure—Addition of a Nucleophile, and Ring Opening.     

Molekül‐ und Kristallstruktur von Quecksilber(II)‐α‐Amino‐γ‐methylmercapto‐butyrat,Hg(Met)2

Molecular and Crystal Structure of Mercuric α‐Amino‐γ‐methyl‐mercapto‐butyrate, Hg(Met)₂ The mercuric salt of deprotonated methionine, Hg(Met)₂, was obtained as colourless needles from aqueous solutions of methionine and HgCl₂ or HgO, respectively. The crystal structure (monoclinic, P2₁, Z = 2, a = 984, 2(2), 507, 96(6), c = 1574, 2(3) pm, β = 93, 05(2)°; R_all = 0, 055) exhibits formula‐like molecules with strong Hg—N coordination at a distance of 216 pm; one oxygen atom adds to a chelate like N—Hg—O coordination. Stacking of these molecules adds two oxygen atoms of different methionate anions to an effective 2+2+2 ?octahedral”? coordination around the mercuric ion. Thereby a layer structure parallel (001) is formed with the methyl‐mercapto function on top and bottom of these layers.     

Étude d'équilibres en solution à l'aide des échangeurs d'ions : I Dissociation du perchlorate d'argent et de l'acide nitrique dans les mélanges eau—acide acétique—acide perchlorique ou acide nitrique

A theoretical relationship postulated between the distribution coefficient of a monovalent element and the parameters upon which it depends (acid concentration in solution, dissociation constants of the acid and the salt, selectivity coefficient of exchanged ions) has been verified for the dissociation of silver perchlorate in water—acetic acid—perchloric acid mixtures. The dissociation constants found have been compared with the experimental values obtained by potentiometric measurements. The relationship established has been employed for the determination of nitric acid dissociation constants in water—acetic acid-nitric acid mixtures containing less than 25 % by weight of water. From the results the pK value for nitric acid in pure acetic acid has been evaluated by extrapolation. The theoretical relationship might be used to determine an acid dissociation constant when the dissociation constant of a salt is known and vice versa.     

Hétérocyclisations intramoléculaires par réaction d'oxymercuration. I — synthèse et configurations des hétérocycles

We have accomplished the intramolecular oxymercuration of γ-δ ethylenic alcohols, with different mercuric salts under different conditions. By “in situ” reduction, or by direct reduction of isolated mercuric compounds, we obtain, in some cases, diastereoisomers with different relative yields.     

Études en série indolique—XI : Synthèses dans la série de la dihydro-18, 19-dl antirhine

Three methods for the synthesis of (dl) 18, 19-dihydroantirhine and its epimers at C-15 and C-20 have been compared; a modified Polonovski reaction, mercuric acetate oxidation of the appropriate N-alkylpiperidine, and hydrogenation according to Wenkert of the appropriate pyridinium salt.     

Étude de l'erreur acide de l'électrode de verre en milieu aqueux: Tome III. Solutions mixtes d'acide et de sel alcalin

The acid error of the glass electrode is studied in mixed solutions of acid and alkaline salt with common anion. Measurements have been made by direct comparison with the hydrogen electrode. The experimental results confirm the view that the acid error arises from anion penetration into the glass. An empirical equation is proposed in which this error is expressed in terms of cation concentration in mixed solution.     

Nucleophilic coaction during one-electron oxidation of hydroxyaromatic compounds

Conclusions The role of internal catalysis during one-electron oxidation of hydroxyaromatic compounds by mercuric salts, the possibility of which is determined by the nature of the salt anion, was shown.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2601–2603, November, 1974.     

Sels d'atdp—19: Cinetique de decomposition d'un chlorure d'atdp en chlorure d'alkyle et HMPT. Effet de solvant et effet de sel

The kinetics of decomposition of the 2-methyl-1-pentyloxy(trisdimethylamino)phosphonium chloride, was measured in several solvents. The experimental kinetic order towards the chloride anion was in the range from 2, in a dissociating solvent, to 1 in non dissociating solvents. Hence we afford experimental confirmation of an earlier prevision in the literature. A linear correlation of log k with the dielectric constants of the solvents was found in the case of the systems exhibiting first order kinetics, contrasting with the classical correlation in $\text{1}\text{?}$, generally observed for the reactions between ions of opposite charge. The salt effect has been measured and interpreted. It allows the performance of kinetic runs for non hindered, very labile ATDP salts, by their replacement by a mixture of an ATDP perchlorate and an aryloxyphosphonium chloride, both of which are stable.     

Synthèse de polyéthers polycycliques. 1 Stéréosélectivité de l'hétérocyclisation d'alcools tétrahydrofurfuryliques γ,δ-éthyléniques par les sels mercuriques

The intramolecular oxymercuration of the l-(2-tetrahydrofuryl)4-penten-1-ols (5) by merruric salts followed by reductive demercuration affords the 2-methyl-5-tetrahydrofuryltetrahydrofuran (9) as a mixture of cis and trans isomers in good yields. By using mercuric acetate, each isomier threo 5a and erythro 5b gives the trans isomer, 9d and 9b, respectively, as the major products. On the other hand, cyclizations carried out with mercuric chloride are not stereoselective.     

Organomercury compounds : XXVI. Thermal decomposition of mercuric 2,6-disubstituted benzoates

The main thermal decomposition path for mercuric 2,6-disubstituted benzoates, (RCO₂)₂Hg (R = 2,6-X₂C₆H₃; X = F, Cl, Br, or Me), can be varied considerably. In boiling dimethyl sulphoxide, decarboxylation occurs giving the corresponding diarylmercurial (X = F or Cl) or RHgO₂CR derivative (X = Me or Br). There is considerable competition from reaction of the mercuric salt with the solvent in the last three cases. With boiling pyridine as medium, the 2,6-difluorobenzoate yields a mixture of R₂Hg and RHgO₂CR derivatives, but the 2,6-dichlorobenzoate only gives (RCO₂)₂Hg(py)₂. Thermal decomposition of the mercuric benzoates under vacuum yields the carboxylic acids and complex mercuration products, mainly based on 3-mercurated 2,6-disubstituted benzoates, with partial additional mercuration and/or decarboxylation. Pyrolysis of mercuric 2,6-dichlorobenzoate at atmospheric pressure results in both mercuration and decarboxylation, giving m-dichlorobenzene as the main volatile product and a complex mercurial with 1,3-dimercurated-2,6-dichlorobenzene repeating units and 2,6-dichlorophenyl terminal groups.     

Improving the Selectivity of the Determination of Organophosphorus Insecticides and Carbamates by Enzyme Assay

Enzyme assay is proposed for improving the selectivity of the determination of an organophosphorus (carbamate) insecticide in the presence of a heavy-metal salt in a sample (exemplified by a model system containing proserine and mercuric bromide). The method involves the use of a substrate–indicator system based on acylthiocholine and Ellman's reagent (or its derivative).     

METHYLMERCURY: PHOTOCHEMICAL TRANSFORMATION OF MERCURIC SULFIDE INTO METHYLMERCURY IN AQUEOUS SOLUTIONS1

Abstract. The photochemical reaction of mercuric sulfide was studied in aqueous solutions. The photo-solubilization of mercuric sulfide occurred under irradiation with light of ≤650nm and was enhanced in the presence of oxygen and electrolytes. The resultant mercuric ions were easily methylated in the presence of acetate ions via the photosensitized reaction by the simultaneously produced "photo-sulfur" under irradiation with light of ≤420nm. The photoelectrochemical studies of mercuric sulfide electrode revealed that black mercuric sulfide was an n -type semiconductor and the photo-current due to the dissolution as mercuric ions was observed on anodic polarization. The photo-solubilization of mercuric sulfide may be interpreted in terms of the local-cell mechanism.     

Synthese et etude de celluloses echangeuses d'ions. Leur emploi dans l'epuration des eaux residuaires de l'industrie textile—1: Synthese d'une cellulose greffee par des chaines poly (acide acrylique) et d'une cellulose renfermant des fonctions ammonium quaternaire

For use as ion exchangers and particularly as purification agents for textile industrial effluents, cellulose grafted with polyacrylic acid and cellulose substituted by quaternary ammonium functions have been prepared. For both syntheses, the influences of experimental parameters have been studied in detail and the optimum conditions for large-scale preparation have been determined. Large amounts of modified cellulose have been obtained and tested in industry (cf. part III). The grafting by acrylic acid has been carried out by the ceric-ion method; the quaternary ammonium cellulose has been obtained by condensation of cellulose with epoxy propyl triethyl ammonium chloride. Synthesis of this salt in the presence of cellulose has been achieved so that the quaternary ammonium cellulose can be obtained from cellulose and epichlorhydrin in one step.     

Reaction of Methyl Iodide-Mercuric Iodide with Phenothiazines

Reaction of phenothiazine with methyl iodide in the presence of mercuric iodide did not yield a product with a methyl group attached to the sulfur atom. Instead, a quaternary ammonium salt was obtained. This paper is intended to provide correct information with supporting evidence for this raction.     

Reactions of hexamethylditin with alkylmercury salts I. Stoichiometry and rate step

Hexamethylditin in methanol solution reacts rapidly with mercuric chloride to yield mercury and trimethyltin chloride. With alkylmercuric salts the reaction is complex, yielding tetraalkyltin and/or dialkylmercury, depending upon the reactivity of the alkylmercuric salt. An electrophilic substitution mechanism involving trimethylstannyl mercurials as transient intermediates is suggested. The reaction of hexaalkylditin with diarylmercury is suggested to follow a homolyric pathway.     

Hydrosilylation d'alcools en milieu sel fondu

Hydrosilylation of alcohols has been carried out in molten dodecylammonium propionate at low temperature (70°C). The salt is used as solvent and as catalyst.