Sulpho Group Research Articles

The mechanism of photochemical chain substitution of chlorine by sulpho group n 4-chloro-1-hydroxynaphthalene

On irradiation of 4-chloro-1-hydroxynaphthalene in aqueous solution of sodium sulphite the chain photosubstitution reaction of chlorine by sulphite is observed. There are two mechanisms of photoinitiation of a chain reaction: the interaction of the triplet molecule of substrate with its nonexcited molecule and an electron photoejection. Independently of the mechanism of photoinitiation two intermediates—a radical anion of 4-chloro-1-hydroxynaphthoxide anion and 4-chloro-1-naphthoxy radical are formed. Naphthoxy radicals react with reducing agents (sodium sulphite, potassium iodide) forming sulphite radical anions. The formation of two different radical anions leads to two competitive mechanisms of the chain substitution reaction: an S RN1 mechanism and a mechanism with the participation of sulphite radical anions.

Self-doped polyanilines electrochemically active in neutral and basic aqueous solutions.: Electropolymerization of substituted anilines

To obtain polyaniline (PAn) films that are electrochemically active in neutral aqueous solutions, the electropolymerization of three substituted anilines (anthranilic acid, m-aminobenzoic acid and m-aminobenzenesulphonic acid) was studied. Cyclic voltammograms of copolymers of substituted and unsubstituted anilines (monomer ratio 1 : 1) showed redox activity in neutral and basic aqueous solutions up to pH 10. The decrease in redox activity occurred more than 5 pH units higher than in the case of the usual PAn. Among aniline derivatives taken for the synthesis, a meta position and a sulpho group were preferable to produce the optimal self-doped PAn. A new redox couple in the negative potential region (E °′ = 0.24 V, Ag/AgCl, pH = 1) was observed. Self-doped polyanilines were also investigated by means of impedance spectroscopy.

Synthesis and properties of naphthalimide acid dyes

A series of monoazo dyes has been obtained using 4-aminonaphthalimide and 4-amino-N-methylnaphthalimide and their 3-sulpho derivatives as diazo components. Derivatives of 1- and 2-naphthol were used as coupling components. It was found that in the electronic spectra of these dyes, additional bathochromically shifted bands of different intensity appear. This effect is caused by the occurrence of the dyes in equilibrium of azo and hydrazone forms. The sulpho group in the ortho(3-) position to the azo group influences the dulling of the colour by weakening coupling between the two parts of the dyes. At the same time, it gives better solubility and increases exhaustion and fastness on wool and polyamide.

Dye-photoinitiated chain reaction of halogen substitution by a sulpho group in halogenonaphthols

The dye-photosensitized chain reaction of halogen substitution by a sulpho group has been found in halogenonaphthols. A sulphite radical anion is formed in the initiation step and takes part in the propagation step. The quantum yield of the dye-photosensitized reaction of halogen substitution by a sulpho group in 1-chloro-2-naphthol depends linearly on the chloronaphthol concentration and on the reciprocal square root of light intensity absorbed by the dye. The termination step is the recombination of the sulphite radical anion.

ChemInform Abstract: Syntheses and Properties of Optically Active 2‐Substituted Taurines.

AbstractThe taurines (IV) are synthesized starting from (S)‐(I) via their mesylates, either by direct HCl‐deprotection followed by Na2SO3, or by preceding bromination of the mesylates.

Syntheses and properties of optically active 2-substituted taurines

The synthesis of nine 2-substituted taurines (5a–i), including the marine natural product D-cysteinolic acid (5f), are described. These involve the successive conversion of N-t-butoxycarbonyl(Boc)-protected amino acid esters (1) into the N-Boc-2-aminoethanols (2), their O-mesylated derivatives (3), the deprotected 2-aminoethyl methanesulphonates (4), followed by the replacement of the mesyloxy group by a sulpho group to give the optically active taurines (5a–e,g–i). Hydrogenolysis of 2-benzyloxymethyltaurine (5e) gives D-cysteinolic acid (5f). The structure of another of the products, (5b), is also confirmed by an alternative synthesis from N-Boc-valine methyl ester (1b)via two β-bromoethylamine derivatives, (6b) and (7b).

The chemical conversion of C-terminal glycines in peptides into taurine

The first chemical conversion of C-glycine in dipeptides into taurine has been achieved using a general substitution of a sulpho group for a halogeno or mesyl group via the corresponding amino acid 2-halogenoethyl-or 2-methanesulphonyloxyethyl-amides, each of which was prepared from the ethanolamide obtained by LiBH4 reduction of a protected dipeptide containing a C-glycine ester.

Aromatic sulphonation. Part 92. Sulphonation of the three methylphenols and the six dimethylphenols in concentrated aqueous sulphuric acid; and the lsomerization of some of the resulting sulphonic acids and of m-xylene-2-and o-xylene-3-sulphonic acid

The isomer distributions for the mono- and di-sulphonation of the three methylphenols in 81.6–90.0% sulphuric acid and of the six dimethylphenols in 84.9% sulphuric acid at 35 °C have been determined by means of 1H n.m.r. spectroscopy. Products that would result from demethylation, disproportionation, or ipso-substitution have not been observed. The monosulphonation isomer distribution of each of the three methylphenols is independent of the sulphuric acid concentration. 2,4-Dimethylphenol in 84.9% H2SO4yields 19% 5- and 79% 6-sulphonic acid, and 2,6-dimethylphenol yields 28% 3- and 72% 4-sulphonic acid. With the phenols (2), (3), (5), and (7), which have positions both ortho and para to the –OH substituent available for sulphodeprotonation, the yield of ortho-substitution is relatively high, viz. 44, 45,36, and 27%, respectively. The mono- and di-sulphonic acids of which the sulpho group is between the –OH and an –Me group are unstable under the reaction conditions employed, with the exception of the 3,5-dimethylphenol-2-sulphonic acid. It is proposed that their isomerization proceeds by protiodesulphonation followed by resulphonation to yield the more stable sulphonic acid isomer(s). From a kinetic analysis of the calculated first-order rate coefficients for protiodesulphonation, it is concluded that the unprotonated substrate species is the entity undergoing the protiodesulphonation.

Aromatic sulphonation—80: Sulphur trioxide sulphonation of some tri- and tetra-methylnaphthalenes

1,2,3-Trimethylnaphthalene (1,2,3,-Me 3N), 1,4,5-Me 3N, 1,6,7-Me 3N, 1,2,3,4-Me 4N and 1,4,6,7-Me 3N have been sulphonated with SO 3 in nitromethane and the isomer distributions of the mono- and di-sulphonic acid mixtures, obtained by reaction with 1 equivalent of SO 3 at 0° and 3 equivalents of SO 3 at 12° respectively, are reported. The sulphodeprotonation isomer distribution follows the reactivity order predicted by the localization energies, provided that steric factors are taken into account, i.e. that sulphodeprotonations peri to a methyl and sulpho group do not occur. Disulphonation of 1,4,5-Me 3N and 1,4,5,8-Me 4N leads predominantly to the 3,6- and 2,7-disulphonic acid respectively, i.e. the “non-crossed” disulphonic acids.

SULPHONATION OF THE TEN DIMETHYLNAPHTHALENES AND 2-METHYLNAPHTHALENE: ISOMER DISTRIBUTION AND CORRELATIONS WITH MOLECULAR ORBITAL THEORY

Abstract The isomer distribution for the mono- and di-sulphonation of 2-methylnaphthalene (2-MN) and all ten dimethylnaphthalenes (DMN's) with SO3 in nitromethane as solvent were determined at 0° and/or 12°C. From the substitution pattern it is evident that steric factors play a more important role in the sulphonation than in most other electrophilic substitutions. In the disulphonations the substitution of the second sulpho group occurs in part in the same ring as the first one. This may infer that the directing effect of the first (pyro)sulphonic acid group is relatively small. The positional order of substitution for the monosulphonation of a given substrate is in excellent agreement with that predicted by the localization energies, calculated by a simple Hückel m.o. treatment, utilizing the inductive model for the methyl substituent, provided that allowance is made for steric factors.

CATALYTIC EFFECTS IN THE AMINOLYSIS REACTIONS OF ARYLSULPHONIC ACID DERIVATIVES IN NON-AQUEOUS MEDIA

Abstract The catalytic effects of organic bases in reactions of arylamines with arylsulphonic acid derivatives, ArSO2X (X = Cl, Br, OSO2Ar) in aprotic media are characterised by the following regularities. 1. The activity of 3- and 4-substituted pyridines, N-alkyl- and N-phenylimidazoles is desribed by the common Bränsted relationship. Substituents in positions 2 and 2,6 of the pyridine molecule have a strong steric influence. Tertiary cyclic amines of quinuclidine type with the same basicity as pyridines and imidazoles have more higher activity than the latter. N-Oxides of pyridine which are 4–5 pKa units less basic than the corresponding pyridines have the catalytic activity 100 times as much, as compared with them. 2. The intensity of the catalytic action of pyridines and their N-oxides alters insignificantly with changing the leaving group X in the substrate, somewhat increasing in the order Cl < Br≤OSO2Ar. 3. The activity of pyridine bases increases with increasing the solvent solvating ability. The inhibiting influence of the X− anione on the rate of catalytic reaction displays in media of high polarity (nitrobenzene, acetonitrile). These regularities are explained in terms of the nucleophilic mechanism of catalysis which is supported by isolating intermediate adducts of tertiary amines (in particular 4-N,N-dimethylaminopyridine) with arylsulphonic acid bromides and anhydrides and by studies of their reactivity towards arylamines in methylene chloride. Compounds of bifunctional nature (carboxylic acids) do not accelerate the reaction under consideration unlike a similar substitution process at the carbonyl C-atom. The cause of this seems to be a different geometry of transition states in substitution at the sulpho group S-atom and at the carbonyl carbon, respectively.

Hydrolysis of aromatic sulphonic acids in industrial effluents. I. Hydrolysis of 7‐hydroxy‐2‐naphthalenesulphonic acid

AbstractThe protodesulphonation of 7‐hydroxy‐2‐naphthalenesulphonic acid (F‐acid) was investigated in dilute aqueous sulphuric acid at temperatures of 522–553 K. The hydrolysis of the sulpho group is irreversible and F‐acid can be completely converted into 2‐naphthol in a short time. The hydrolysis rate depends strongly on the temperature and on the sulphuric acid concentration; a rate equation was derived from the experimental data.

The formation of exchangeable sulphite from adenosine 3'-phosphate 5'-sulphatophosphate in yeast.

A new low-molecular-weight bound sulphite was found in yeast enzyme reaction systems which convert the sulphur of 35S-labelled adenosine 3'-phosphate 5'-sulphatophosphate into exchangeable radioactive sulphite. This bound sulphite was separated from other components by paper electrophoresis and Sephadex G-25 chromatography, and shown to be a peptide with multiple thiol groups and an estimated mol.wt. of 1400. The labelled sulphur in this peptide is highly exchangeable with unlabelled sulphite, but exchangeability decreases with time and freeze-drying. The low-molecular-weight acceptor is tightly bound to enzyme B of the yeast system and, apparently, accepts the sulpho group of adenosine 3'-phosphate 5'-sulphatophosphate and is released as bound sulphite only in the presence of enzymically or chemically reduced fraction C. It is proposed that the low-molecular-weight acceptor is a carrier peptide which, after release of the reduced sulphur, becomes re-oxidized and returns to enzyme B. Fraction C appears to function as an obligatory reductant of the oxidized acceptor before it can accept another-SO-3-moiety from adenosine 3'-phosphate 5'-sulphatophosphate. These findings are consistent with mechanisms proposed for sulphate reduction in spinach and Chlorella, and suggest that fraction C is the natural thiol required in these systems. An improved column technique for the preparation of adenosine 3'-phosphate 5'-sulphatophosphate is described.

Organosilicon compounds XXXII. The cleavage of aryl-silicon bonds by sulphur trioxide

Aryltrimethylsilanes, ArSiMe 3, react with sulphur trioxide in carbon tetrachloride to give the sulphonic esters, ArSO 2OSiMe 3, which undergo hydrolysis readily to the sulphonic acids ArSO 3H. The reaction provides a means of introducing a sulpho group at a specific position of the aromatic ring; thus from m-tolyltrimethylsilane, m-toluenesulphonic acid is obtained in 80 % yield. The reaction has been used to prepare from the compounds m- or p-R 3SiC 6H 4-SiMe 3, where R = Me or Ph, the acids m- or p-R 3SiC 6H 4SO 3H and their derivatives, the first examples of compounds containing sulphoaryl groups attached directly to silicon.

The Relation between the Rate of Formation of the Chromium Complexes of a Dye and its Value in the Metachrome Process

A study has been made of the rates of formation and the nature of the chromium complexes of selected dyes in order to ascertain whether or not a relationship exists between the rate of complex formation and the suitability of a dye for application by the metachrome process. The results indicate that, in the case of azosalicylic acid compounds containing a sulpho group, the dyes are unsuitable for use in the metachrome process probably because of co–ordination of chromium with the sulpho group instead of, or as well as, chelation of chromium with the salicylic acid group. The examination of the rates of formation of the chromium complexes of a series of 00′‐dihydroxyazo compounds of diminishing value as metachrome dyes has revealed that the greater the rate of chromium‐dye complex formation the more suitable is the dye for application by the metachrome process. The results suggest that both substantivity and rate of complex formation play important rdles in the determination of the value of a metachrome dye, and that both of these factors should be as high as possible, consistent with solubility.The experimental data demonstrate that, in the case of the series of 00′‐dihydroxyazo dyes employed, the final product of reaction of dye and chromium salt is the primary complex, in which one molecule of dye is associated with one atom of chromium. This product is formed via the chromium salt of the dye and a complex in which three molecules of the dye are associated with one atom of chromium. The analyses have not disclosed whether conversion of the 3: 1 complex occurs directly to the 1: 1 complex or whether the 2: 1 acidic complex is formed as an intermediate product.

On Recent Progress in the Coal-Tar Industry 1

II. AZO-COLOURS.—Amongst the most important of the artificial colouring matters may be classed the so-called azo-colours. These colours are chiefly bright scarlets, oranges, reds, and yellows, with a few blues and violets. They owe their existence to the discovery by Griess, in 1860, of the fact that the so-called azo-group - N = N - can replace hydrogen in phenols and amido-compounds. But it is to Dr. O. N. Witt that is due the honour of having given the first start in a practical direction to the chrysoidine class of azo-colours by the discovery of chrysoid-ine, and perhaps still more so by the suggestions contained in a paper read before the Chemical Society. Dr. Caro, of Mann-neim, was also acquainted with several compounds which belong to this class at the time Witt published his results, but it does not appear that he made practical use of them until Witt intro duced the chrysoidines and tropeolines. To Roussin, of the firm of Poirrier of Paris, is due the credit of having first brought into the market some of the beautiful azo-derivatives of naphthol. Griess, therefore, as the original discoverer of the typical com pounds and reactions by which the azo-colours are obtained, may be considered as the grandfather, whilst Roussin and Witt are really the fathers, of the azo-colour industry. Nor must it be forgotten that it is to Perkin we owe the recognition of the value of the sulpho group in relation to azo-colours, a discovery patented in 1863. Moreover it is interesting to note that changes in colour from yellow to red and claret are effected by the increase in the molecular weights of the radicals introduced a well as by the relative positions occupied by these groups.