Coulometric titrations with mercury(I) and (II) determinations of secondary amines and mercaptans

A study of the titration of aliphatic amines and mercaptans with electrolytically generated mercury(II) reagent is reported. Amines were titrated after conversion to their corresponding dithio-carbamic acids by reaction with carbon disulfide. Using this procedure, a 3.10^-4F solution of secondary amine was titrated with an accuracy of better than 1% and a concentration of 3.10^-6F with an accuracy of better than 2%. Primary amines constituted an interference in this procedure but were removed prior to the titration with salicylaldehyde. Tertiary amines were found not to interfere. Comparable titrations with generated silver ion did not give quantitative results.The application of electrolytically generated rnercury(II) reagents for the titration of another organic functional group, sulfhydryl, was also studied. The titration of a sulfhydryl compound (cysteine) was studied briefly. Amounts of cysteine down to 1. 29 mg in 100 ml of solution (1.3.10^-4F) were determined with an accuracy of better than 1%. Smaller amounts of cysteine down to 0.26 mg (2.10^-5F) were determined with about 3% accuracy.     

Microdetermination of secondary aliphatic amines using a copper ion-selective electrode

A simple, accurate, and selective method is described for the microdetermination of aliphatic secondary amines. The method is based on their reaction with carbon disulfide and ammoniacal copper sulfate at 40 °C for 30 min to yield copper dialkyldithiocarbamate. The excess copper is then measured by titration with EDTA or NaDDC using a copper ion-selective electrode. A mean recovery of 98.2% with a standard deviation of 0.8% is obtained for aliphatic secondary amines and their salts having a wide range of pK_a.     

一锅合成异硫氰酸酯

以N,N-二乙基乙胺(Et₃N)为碱,甲苯为溶剂,伯胺和CS₂为原料,叔丁基碳酸二乙基磷酸酐(3)为脱硫试剂,在n(伯胺):n(CS₂):n(Et₃N):n(3)=1:1.1:3.3:1.1,二硫代甲酸盐合成段反应温度为室温,脱硫反应段为-5 ℃至室温的实验条件下,两步一锅合成了系列烷基、芳基和双功能基异硫氰酸酯化合物,收率77%96%。 本方法底物适用范围广,操作简单,对胺的各种保护基团耐受,不引起消旋化副反应。 脱硫剂3作为一种新的脱硫试剂,商业易得,安全有效。     

Studies on reactions of the N-phosphonium salts of pyridines. XIII. Direct polycondensation reaction of carbon dioxide or disulfide with diamines under mild conditions

Polyureas of high molecular weight were obtained by the direct polycondensation reaction of carbon dioxide with diamines at 40°C for several hours under a pressure of carbon dioxide (below 30 atm) by use of diphenyl phosphite in pyridine. Optimal temperature and pressure were 40°C and 20 atm of carbon dioxide. The polycondensation reaction was also affected by solvents and type and amounts of tertiary amines. Pyridine was most effective as tertiary amine and solvent as well. Of the phosphorous compounds used, triaryl phosphites and diphenyl phosphite were most effective, but trialkyl phosphites failed to give polymer. The reaction was assumed to proceed via a carbamyl N-phosphonium salt of pyridine formed by dephenoxylation of phosphites. Similarly, polythioureas were prepared by heating a mixture of carbon disulfide, diamines, and diphenyl phosphite in pyridine at 40°C for 6 hr under nitrogen.     

Three-component reaction between amines,carbon disulfide and electron-deficient derivatives of chloropyridine or chlorobenzene: synthesis of 3,6-diazaspiro[4.5]deca-2,7,9-trien-6-ium chloride and dithioylcarbamates derivatives

In this study, three-component reaction of some primary and secondary amines with carbon disulfide in the presence of electron-deficient derivatives of chloropyridine or chlorobenzene in the CH₃CN as a solvent is reported. The reaction of primary amines with carbon disulfide and electron-deficient compounds of chloropyridine or chlorobenzene after 6–8 h afforded the three-component addition product. The reaction of secondary amines with carbon disulfide and electron-deficient compounds of chloropyridine or chlorobenzene after 3–4 h afforded the two-component addition product. The product(s) of reactions were purified by recrystallization or column chromatography and their structures were identified by spectroscopy techniques such as ¹H-NMR, ¹³C-NMR, IR, UV and elemental analysis. The reactions were carried out under mild conditions and without using a catalyst.     

Concerning the gas chromatographic determination of amphetamine as (1-phenyl-isopropyl)-isothiocyanate

Amphetamine (I) reacts spontaneously at room temperature with carbon disulfide to form (1-phenyl-isopropyl)-isothiocyanate, which was identified by UV.-, IR.- and mass spectrometry. This reaction is used for the analytical determination of I by gas chromatography. The characteristic peak shift which occurs after addition of carbon disulfide differentiates I from N-methylamphetamine (II). The method is applied to urine analysis of I and II (which partially metabolizes to I) and might be useful in doping control.     

Upgrading CO2 by Incorporation into Urethanes through Silver‐Catalyzed One‐Pot Stepwise Amidation Reaction

One‐pot two‐step stepwise reaction of terminal propargylic alcohols, carbon dioxide, and primary/secondary amines for the effective synthesis of various urethanes through robust silver‐catalysed C‐O/C‐N bond formation is reported. Catalytic activities were investigated by controlling catalyst loading, reaction pressure and time, and very high turnover number (turnover frequency) was obtained: 3350 (35 h⁻¹) with 0.01 mol% silver catalyst under 0.1 MPa, and up to 13360 (139 h⁻¹) with 0.005 mol% silver catalyst under 2.0 MPa at room temperature. The strategy was ingeniously regulated, and synchronously afforded a wide range of β‐oxopropylcarbamate and 1,3‐oxazolidin‐2‐one motifs in excellent yields and selectivity together with unprecedented high turnover number (TON) and turnover frequency (TOF) value.     

Low-temperature reduction of silver(I) oxide particles with long chain alcohol

The mechanism of reducing silver(I) oxide particles to silver metals was studied using myristyl alcohol as a reducing agent. The reduction temperature of silver oxide with myristyl alcohol decreased to 150 °C from the temperature of silver oxide in air, 400 °C. The reduction temperature was decreased by myristyl alcohol reacting with silver oxide, which was confirmed by our reaction equation model obtained by gas chromatography determination, pyrolysis gas chromatography–mass spectrometry, and Karl Fischer titration. An endothermic of 153.7 kJ mol^?1 in the reduction of silver oxide with myristyl alcohol calculated from the reaction model using Hess’s law was coincident with that obtained experimentally by differential scanning calorimetry measurements.     

Silver supramolecule catalyzed multicomponent reactions under mild conditions

A novel supramolecular complex [Ag(L)(NO(3))] (1) was synthesized by reaction of the oxazoline-containing ligand 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (L) with silver(I) nitrate and its structure was determined by single-crystal X-ray diffraction. Structurally speaking, the one-dimensional (1D) zigzag chains of 1, in which the Ag(I) is three-coordinated with distorted trigonal-planar coordination geometry, are linked together by the hydrogen bonding interactions to form a three-dimensional (3D) supramolecular structure. It was found that the silver supramolecule 1 catalyzes the three-component coupling reactions of aldehyde, alkyne, and amine in the air at room temperature to generate propargylic amines with high efficiency. No additional co-catalyst or activator is required. A variety of aldehydes and amines were used to demonstrate the versatility of the reaction.     

Use of iodide and silver/sulfide ion-selective electrodes for the determination of some tertiary amines and alkaloids

Summary Some tertiary amines and alkaloides were determined by reaction with methyl iodide at 43 °C. The produced quaternary ammonium iodide salts were potentiometrically titrated with standard silver nitrate solution using either the iodide or silver/sulfide ion-selective electrode. The effects of solvent, temperature and time of reaction were examined. An average recovery of 99.0% and 98.9% with standard deviations of 0.73 and 0.52 were obtained for the studied amines and alkaloides, respectively.

---

Verwendung der Iodid-bzw. Silber/Sulfid-selektiven Elektrode zur Bestimmung einiger tertiärer Amine und Alkaloide

     

Synthesis of Vinyl Phenyl Ether and Its Use for Ammetric Titration of Silver(I)

Catalytic vinylation of phenol with acetylene at atmospheric pressure was studied. The yield of vinyl phenyl ether was determined as influenced by the solvent, reaction temperature, and catalyst amount. The mechanism of formation of vinyl phenyl ether was proposed. Ammetric titration of silver(I) with a solution of vinyl phenyl ether in nonaqueous acetic acid solutions was performed.     

3－烷基-4-羟基-2-噻唑烷硫酮-4-羧酸乙酯的一锅煮合成

Ethyl 3-alkyl-4-hydroxy-2-thioxothiazolidine-4-carboxylates were prepared in excellent yields from the reaction of corresponding primary amines with carbon disulfide and ethyl 3-bromo-2-oxopropanoate in the presence of anhydrous potassium phosphate in DMF at room temperature within 1 h. The structures of the highly functionalized products were corroborated spectroscopically （IR, ^1H NMR, ^13C NMR, EI-MS） and by elemental analyses. A plausible mechanism for such type of cyclization was proposed.     

Silver-gelatin method for determination of inorganic peroxides in alkaline solution

An aqueous solution of gelatin binds silver(I) at pH >7 and a yellow silver sol can be produced from this by reduction. The sol reacts with peroxide in strongly ammoniacal medium to give a colourless solution. The reaction may be used for photometric and visual titration of peroxide with relative standard deviations of 0.4 and 1.5% respectively and also for its spectrophotometric determination.     

Fe3O4@SiO2‐copper sucrose xanthate as a green nanocatalyst for N‐, O‐ and S‐arylation

Formation of C(sp²)–X bonds was carried out using a Fe₃O₄@SiO₂‐copper(I) sucrose xanthate nanoparticle catalyst with the aid of the copper(I) xanthate moiety in the catalyst which was prepared from the reaction between sucrose and carbon disulfide through an alkaline medium via the traditional Zeise approach. Various techniques were employed for the characterization of these novel nanoparticles. Three sorts of heteroatoms, N, O and S, successfully underwent heteroatom arylation to produce secondary or tertiary amines, ethers and thioethers, respectively.     

Transition-metal-catalyzed reactions of propargylamine with carbon dioxide and carbon disulfide.

The reactions of propargylamine derivatives with carbon dioxide and carbon disulfide have been systematically examined in the presence of transition-metal catalysts. Pd(OAc)(2) is the best catalyst for the formation of the corresponding oxazolidinones. In addition, we found that, in the reaction of propargylamine with carbon dioxide catalyzed by palladium(0) metal catalyst in toluene, both oxazolidinone 1 and imidazolidinone 2 could be obtained under mild reaction conditions at the same time. The reaction of 1 with primary and secondary amines has been examined. A plausible reaction mechanism for the formation of 2 was proposed. In addition, in this paper, we first disclosed the ligand's effect on this reaction. Using PBu(t)(3) as a ligand with Pd(2)(dba)(3), 1 was exclusively formed in 90% yield.     

The Action of Carbon Disulfide and Sulfur on Enamines,Ketimines, and CH Acids

The reaction of sulfur, carbon disulfide, and enamines at room temperature leads mainly or exclusively to 3H-1,2-dithiole-3-thiones; these are occasionally accompanied by 2H-1,3-dithiole-2-thiones, which can also be prepared by a modified procedure. Many enamines react with sulfur at room temperature to form thioamides. At about 50°C, enamines of acetophenone give 2-benzylidene-4-phenyl-2H-1,3-dithiol. The action of isothiocyanates and sulfur on enamines leads to the formation of thiazolidine-2-thiones. 2H-Thiopyran-2-thiones can be prepaAred from enamines or dienamines with carbon disulfide at room temperature. The reaction of ketimines (Schiff bases) with carbon disulfide and sulfur yields 3H-1,2-dithiole-3-thiones or isothiazoline-5-thiones. The reaction of alkynes with sulfur and carbon disulfide leads to 2H-1,3-dithiole-2-thiones. Nitriles containing active methylene groups react with carbon disulfide and sulfur to form 5-amino-3H-1,2-dithiole-3-thiones. When isothiocyanates are used instead of CS₂, the reaction leads to δ⁴-4-amino-thiazoline-2-thiones.     

Solvent‐free one‐pot synthesis of pyrane derivatives

A straightforward and an efficient method for the synthesis of 2H‐pyrans via the one‐pot, reaction of alkyl bromides, carbon disulfide, secondary amines, activated acetylenes and isocyanides under solvent‐free conditions without using any catalyst at room temperature is reported. The method offers several advantages including high yields of products and an easy work‐up procedure. J. Heterocyclic Chem., (2011).     

Convenient synthesis of β,γ-unsaturated γ-dithiolactones from allenylsilver(I) compounds

Allenylsilver(I) compounds react with carbon disulfide to silver(I) 3-alkynedithioates; β,γ-unsaturated γ-dithiolactones are formed by spontaneous cyclisation of these dithioates.     

Coulometric titration of proteins with silver

The sulfhydryl groups of some proteins were studied by a coulometric argentometric titration; disulfide groups in the presence of sulfite were titrated by the same technique. Direct procedures and a technique utilizing excess coulometrically generated silver(I) were used. The latter method enabled small samples (20–1000 μg of protein) to be titrated with a precision of less than 4%. The proteins were generally titrated in both the native state and the denatured state (8 M urea). Bovine serum albumin, α-chymotrypsin, glutathione reductase, human hemoglobin, insulin, β-lactoglobulin, and ovalbumin were examined and the results compared to those of previous workers.     

One-pot synthesis of bis-1,5,3-dithiazepanes and their sorption properties toward silver(I) and palladium(II)

The possibility of one-pot synthesis of bis-1,5,3-dithiazepanes by multicomponent condensation of amines (NH₄Cl, hydrazine, and 1,2-ethylenediamine) with formaldehyde and 1,2-ethanedithiol was described. Their sorption properties relative to Ag(I) and Pd(II) were studied by a static method. It was shown that at room temperature bis-1,5,3-dithiazepanes recovered with high efficiency silver(I) and palladium(II) from nitrate solutions and hydrochloric acid solutions, respectively.