Basic Aniline Research Articles

Efficient Recycling of Catalyst‐Solvent Couples from Lewis Acid‐Catalyzed Asymmetric Reactions in Water

AbstractBioinspired supramolecular architectures were used to compartmentalize highly charged aqua scandium ions into chiral hydrophobic scaffolds for Lewis acid‐catalyzed asymmetric reactions. Recycling without significant loss in catalytic performance is a formidable task, especially for Lewis acid‐catalyzed reactions. This is because Lewis basic impurities derived from starting materials, products, and water are highly competitive ligands for both substrate binding and metal complexation, thus poisoning the Lewis acids and leading to their leaching. Even when basic aniline is used, the architecture allowed for effective suppression of Sc3+ leaching and for reuse of solvent‐catalyst couples in asymmetric ring‐opening reactions without deactivation. Application to asymmetric thia‐Michael addition and hydroxymethylation was also demonstrated. The successful recycling in highly Lewis basic environments underpins the exceptionally high robustness of the chiral Lewis acid catalyst.

Efficient Recycling of Catalyst-Solvent Couples from Lewis Acid-Catalyzed Asymmetric Reactions in Water.

Bioinspired supramolecular architectures were used to compartmentalize highly charged aqua scandium ions into chiral hydrophobic scaffolds for Lewis acid-catalyzed asymmetric reactions. Recycling without significant loss in catalytic performance is a formidable task, especially for Lewis acid-catalyzed reactions. This is because Lewis basic impurities derived from starting materials, products, and water are highly competitive ligands for both substrate binding and metal complexation, thus poisoning the Lewis acids and leading to their leaching. Even when basic aniline is used, the architecture allowed for effective suppression of Sc3+ leaching and for reuse of solvent-catalyst couples in asymmetric ring-opening reactions without deactivation. Application to asymmetric thia-Michael addition and hydroxymethylation was also demonstrated. The successful recycling in highly Lewis basic environments underpins the exceptionally high robustness of the chiral Lewis acid catalyst.

Functionalisation of the uracil ring via palladium-catalysed aminocarbonylation

Iodouracil derivatives (5-iodouracil, 5-iodo-1,3-dimethyluracil) were aminocarbonylated using a set of primary and secondary amines in the presence of in situ palladium(0) catalysts. The formation of carboxamides via single CO insertion was favoured at atmospheric CO pressure. The chemoselectivity toward double CO insertion can be increased by using 40 bar of CO pressure, in this way up to 60% selectivity toward 2-ketocarboxamide was achieved. In the case of 5-iodouracil the corresponding 5-glyoxylamido-uracil derivatives were exclusively formed at 40 bar CO pressure. The only exception is the less basic aniline nucleophile which provided the corresponding carboxamide exclusively. A typical side-reaction took place when 5-iodouracil was used as substrate: this heterocycle, existing in lactam-lactim tautomeric forms, underwent deiodination providing the parent uracil as side-product.

One-pot preparation of an organic polymer monolith by thiol-ene click chemistry for capillary electrochromatography.

A novel organic monolith was successfully fabricated by a one-pot thiol-ene click reaction of triallyl isocyanurate with pentaerythritol tetrakis-(2-mercaptoacetate) and mercaptopropionic acid in the presence of porogens. We investigated the effects of the ratio of monomer and cross-linking agent, the type and ratio of porogen, and click reaction temperature on the permeability and morphology of the prepared poly triallyl isocyanurate-co-pentaerythritol tetrakis (2-mercaptoacetate) monoliths. The monolith was also characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicated that the monoliths had continuous porous framework, good permeability, and high mechanical stability. A series of analytes with different properties such as alkylbenzenes, polycyclic aromatic hydrocarbons, anilines, and phenols were used to evaluate the electrochromatographic performance of the prepared monoliths in pressurized capillary electrochromatography. The prepared polymer monolith showed typical reversed-phase electrochromatographic behavior for hydrophobic substances. Moreover, the prepared monolith showed a mix of reversed-phase and cation exchange interaction modes for basic aniline compounds. The minimum plate height of the monolith was 8.76μm (132100 plates/m) for propylbenzene. These results demonstrated that one-pot thiol-ene click chemistry can provide a simple and reliable method for the preparation of organic monoliths.

Tetraethylorthosilicate as a mild dehydrating reagent for the synthesis of N-formamides with formic acid

The synthesis of N-formamides with formic acid as a formyl source under mild conditions was achieved using tetraethylorthosilicate (TEOS), a low cost and environmentally benign reagent. The mild conditions in this system enable the formylation of a variety of amino acid derivatives including stereochemically labile phenylglycine ethyl ester with 96% ee. This new protocol could also be applied to simple amines including weakly basic aniline derivatives, giving various primary and secondary formamides.

Removal of methylene blue dye using Citrus sinensis

The effluent from textile is an important source of dye pollution. Methylene blue (MB) is a basic aniline dye. At room temperature, it appears as a solid, odourless, dark green powder that yields a blue solution when dissolved in water. The dyeing industry effluents contain high Biochemical Oxygen Demand and Chemical Oxygen Demand value. The need for using cheap and eco-friendly adsorbent for removal of MB dye from an aqueous solution is of paramount importance. The present work aims to investigate the adsorptive characteristics of agricultural waste (Citrus sinensis) for effective removal of dyes from aqueous solutions. Batch adsorption experiments were carried out to observe the effect of various experimental parameters such as pH, contact time, adsorbent dosage and initial dye concentration of MB, and the optimum conditions for these parameters were evaluated. More than 96% removal of dye was attained for all dye adsorbent systems under optimum conditions. The outcomes indicated that C. sinensis can be used as a good low-cost alternative for treatment of effluents containing MB in water.

A Boronium Ion with Exceptional Electrophilicity

During our studies on aromatic borylation,[1] we considered the combination of a highly electrophilic R2BNTf2 reagent with a base that would neutralize the HNTf2 byproduct of borylation without deactivating the electrophile. In principle, these requirements might be satisfied by 1,8-bis(dimethylamino)naphthalene (1), a hindered and exceptionally basic aniline that finds numerous applications as a basic catalyst or reagent due to its legendary lack of nucleophilicity.[2, 3] Strong electrophiles interact weakly, if at all, with the amine nitrogens, and very few examples are known where stable bonds to nitrogen can be formed between 1 and electrophilic groups larger than hydrogen.[2, 4-7] Among these exceptional cases, cyclic boronium structures 2 and 3 are relatively stable because the subunits BH2 and BF2 have minimal steric requirements.[5] However, the more hindered BMe2 derivative 4 has not been detected and no analogous BR2 structures are known.[5a, 8] In view of this long history, we were somewhat surprised to find that an adduct is readily formed simply upon mixing 1 with the 9-BBN bistriflimide reagent 5a despite the transannular steric demands of the 9-BBN core and the need to form adjacent quaternary bonds to boron as well as nitrogen.[9, 10] The remarkable structural features and unusual reactivity of this adduct are the subject of the following communication.

Photocatalytic degradation of organic dyes with manganese-doped ZnO nanoparticles

Manganese-doped and undoped ZnO photocatalysts were synthesized via wet-chemical techniques. Doping of ZnO with manganese (Mn 2+) was intended to create tail states within the band gap of ZnO. These can subsequently be used as efficient photocatalysts which can effectively degrade organic contaminants only with visible light irradiation. Photocatalysts prepared with these techniques, which were characterized with transmission electron microscopy (TEM), infrared spectroscopy (FTIR), photo-co-relation spectroscopy (PCS) and UV–vis-spectroscopy showed significant difference in the optical absorption of Mn-doped ZnO. Enhancement in optical absorption of Mn-doped ZnO indicates that it can be used as an efficient photocatalyst under visible light irradiation. The photo-reduction activities of photocatalysts were evaluated using a basic aniline dye, methylene blue (MB) as organic contaminant irradiated only with visible light from tungsten bulb. It was found that manganese-doped ZnO (ZnO:Mn 2+) bleaches MB much faster than undoped ZnO upon its exposure to the visible light. The experiment demonstrated that the photo-degradation efficiency of ZnO:Mn 2+ was significantly higher than that of undoped ZnO and might also be better than the conventional metal oxide semiconductor such as TiO 2 using MB as a contaminant.

Comparison of historic Grübler dyes with modern counterparts using thin layer chromatography

The aniline dye industry was created in 1856 when William Perkin prepared the dye, mauve, from coal tar. Following that discovery, several dye manufacturing businesses were formed in Western Europe, most successfully in Germany. It was to these companies that early investigators turned to obtain these new dyes for the developing field of biology. In 1880, Dr. Georg Grübler started a company in Germany to supply the needs of biologists. Grübler dyes developed a reputation for excellence. In the study reported here, 29 samples of 12 Grübler dyes were compared to modern counterparts using thin layer chromatography. The dyes studied were basic fuchsine, acid fuchsine, safranine, pyronine, aniline blue, ponceau, gentian violet, methylene blue, orange G, malachite green, and Sudan III and IV. I found that these early Grübler dyes closely resembled modern day counterparts; however, the use of synonyms was confusing and some of the fat stains were mislabeled by modern criteria. The chromatograms of some dyes exhibited smearing, probably representing multiple closely related dye species. The study of old dyes provides interesting comparisons with modern counterparts as the center of dye manufacturing is moving from Europe and the United States to Asia.

Embryonic and postnatal accumulation of homogeneous substance in the endolymphatic sac in the guinea pig

Objective: The endolymphatic sac (ES) of vertebrates contains varying amounts of a homogeneous substance (HS) that stains deeply with basic aniline dyes. Histochemically, HS is characterized as a carbohydrate–protein complex, being both neutral and acidic in nature. In the present study, deposition of HS in the ES was studied in the guinea pig from the 3rd week of gestation to 104 weeks postnatally in order to find out if HS accumulates with age, at which point during embryonic development this substance appears, if its presence is correlated to the sense of hearing and if the amount of substance in the left versus right ear of one and the same animal is correlated to any degree. Methods: Sixty-nine endolymphatic sacs were evaluated in 38 guinea pigs. The ES specimens were sectioned for light and transmission electron microscopy and the amount of HS filling was categorized in four groups: none, low, medium and a high level of substance. Results: The substance was not discerned until after 7 weeks of gestation, when it filled only a minor part of the distal ES lumen. At 9 weeks gestation the nature of the substance altered, becoming homogeneous, as visualized by osmium–toluidine blue staining and approximately filling the distal half of the luminal space. In the postnatal period, 65% of ES specimens were filled with HS to the intermediate or proximal ES, whereas only 6.5% of the ES specimens were devoid of the substance. The extent of filling of the ES in the prenatal temporal bones was significantly less than postnatally ( P<0.0001, χ 2-test). The extent of postnatal filling was not correlated with age. Left and right ears were closely correlated in one and the same animal. Phagocytic cells were often found at the border between clear endolymph and stainable substance. Conclusion: The appearance of HS seemed to coincide temporally with the onset of hearing during the prenatal period indicating that it could play a part in normal inner ear functioning in the guinea pig. The close correlation regarding the level of the HS in the left and right ear, both pre- and postnatally could reflect a general symmetry in endolymph pressure–volume conditions within the inner ear fluid systems, as well as in the environmental hydrostatic pressure in the posterior cranial fossa.

Ultrastructure, autofluorescence, callose deposition and lignification in susceptible and resistant muskmelon leaves infected with the powdery mildew fungus Sphaerotheca fuliginea

Leaves of the susceptible cv. Ananas-Yokneam (AY) and of resistant cvs PI 124111F, PI 124112, PMR-45, PMR-6 of muskmelon ( Cucumis melo) were inoculated with either race 1 or race 2 of Sphaerotheca fuliginea and examined microscopically after staining with Calcofluor, basic aniline blue or phloroglucinol. At 20–24 h post inoculation of the susceptible AY at 23 °C, the fungal spores (both race 1 or race 2) developed one or two germtubes which penetrated into one or two epidermal cells. The penetration zones were surrounded with callose-like material but no autofluorescence nor lignin-like materials were observed in the penetrated epidermal cells. A similar response was observed in PMR-45 inoculated with race 2 (compatible). In contrast, the fungus developed a single germtube on the resistant PI 124111F, PI 124112, and PMR-6 inoculated with either race, as well as in PMR-45 inoculated with race 1, which induced autofluorescence, callose accumulation and lignification in the penetrated epidermal cells. Electron microscopical studies revealed that the rapid collapse of epidermal cells in the resistant cultivars was accompanied by the accumulation of callose-like deposits in cell walls and around haustoria, electron-opaque deposits in the plasma membrane and electron-opaque deposits between the cell wall and the plasma membrane. Occasionally, callose also appeared in epidermal and mesophyll cells adjacent to the penetrated cells. By 96–120 h post inoculation, abundant sporulation was observed in the compatible interactions whereas only 1–3 germtubes with no sporulation were seen in the incompatible interactions. Heat shock or chemical inhibitors (cycloheximide, blasticidin-S, cordycepin, 2-deoxy-D-glucose, α-aminooxyacetic acid, 2,4-dinitrophenol and sodium azide) failed to induce susceptibility in the resistant cultivars. The results suggest a similar structural response to powdery mildew in C. melo cultivars carrying the resistance genes Pm-1 (PMR-45), Pm-2 (PMR-6), Pm-3 (PI 124111F), Pm-4 (PI 124112), Pm-5 (PI 124112) and Pm-6 (PI 124111F).

Mast Cells and Fibrosis

The development of staining techniques for histologic sections led to the initial definitive description of mast cells by a medical student named Paul Ehrlich over 100 years ago. Although other investigators, including von Recklinhausen, 1 had previously described granular cells in the connective tissues of unstained tissue sections, the young Ehrlich was the first to recognize a distinct subset of cells containing granules that stained red or violet when treated with a blue basic aniline dye, dahlia. 2 Thus the metachromatic nature of these cytoplasmic granules drew Ehrlich's attention. He believed that cells containing these granules were overfed, and thus he referred to them as Mastzellen (in German, masten = to fatten). Ehrlich published in his doctoral thesis 3 the astute observations that connective tissue mast cells often surrounded nerves, blood vessels, and glandular ducts, and that mast cell numbers were increased in certain sites of inflammation and neoplasia.

Isolation, propagation, and characterization of a newly recognized pathogen, cilia-associated respiratory bacillus of rats, an etiological agent of chronic respiratory disease

A Gram-negative, filamentous, rod-shaped bacillus which failed to grow in cell-free media was isolated in apparently pure culture from the bronchial scraping and washing of a laboratory rat suffering from chronic respiratory disease by inoculating embryonated chicken eggs via the allantoic route. None of the embryos died during 20 serial passages at weekly intervals. The bacillus was reisolated in embryonated eggs from cesarean-derived barrier-maintained N:SD(SD) rats 8 and 12 weeks after intranasal inoculation with 10th-passage allantoic fluid. The inoculated rats were housed in Horsfall-type units and remained free from other known respiratory pathogens, including mycoplasmas and murine viruses, throughout the study. The bacillus colonized the ciliated epithelial cells of the respiratory tract and caused a marked peribronchial infiltration and hyperplasia of mononuclear cells which progressed with time. The bacillus, ca. 0.2 micron wide by 4 to 6 micron long, stained very poorly with basic aniline dyes but was readily demonstrated with the Warthin-Starry silver technique. It was heat labile (56 degrees C for 30 min); spore forms were not observed. It withstood freeze-thawing and was successfully stored at -70 degrees C. Although no visible means of locomotion was observed with the electron microscope, a slow gliding motility, sometimes with bending and flexing of bacilli apparently adherent to the glass surface, was observed with phase microscopy. As an etiological agent of chronic respiratory disease of rats, this cilia-associated respiratory bacillus (tentatively designated the CAR bacillus) may be the first recognized gliding bacterium known to cause disease in a warm-blooded vertebrate.

100 years of nissl staining

100 years ago a student introduced alcohol fixation and basic aniline dyes into neurohistology. He thus opened up a new era in neurocytology and made microscopical neuropathology possible. Even today the Nissl stain is the most common histological preparation in use.

Plastic embedding techniques in the study of renal biopsies and bone pathology in renal disease

The need for better correlation between light and electron microscopic studies of glomerular morphology has necessitated a search for methods beyond traditional paraffin section techniques. Although the use of plastic embedding for light microscopy appeared a logical solution, poor stain penetration and prolonged processing has hindered the introduction of such techniques into service laboratories. The development of low viscosity epoxy resins mith improved powers of penetration and short polymerization times has solved these difficulties. Methods for staining thin (0.4–1 μm) sections with haematoxylin and eosin, silver methenamine, trichromes and Congo red techniques in addition to the basic aniline dyes used by electron microscopists, have been developed. Slight changes in basement membranes and mesangial matrix and in the various cellular components of the glomerulus can be clearly defined and deposits may be recognized. Immunofluorescence and electron microscopy have been used to confirm the validity of the method. With modifications, similar techniques can be applied to undecalcified bone in the study of bone changes in renal failure. Processing does not interfere with the use of tetracycline labels as markers and the preparations are suitable for quantitative bone histology. Bone changes are invariably present in chronic renal failure. Three main components in various combinations, may be defined. Osteitis fibrosa is commonly seen, osteomalacia occurs less frequently and changes in bone mass, osteosclerosis or osteoporosis, may also be found. Although in general mild and asymptomatic, renal bone disease has become a major problem in patients treated by long-term haemodialysis as these basic patterns of bone changes tend to increase in severity during long-term dialysis.

Metachromatic form of diffuse cerebral sclerosis. I. Diagnosis during life by urine sediment examination.

American Academy of Neurology Dedicated to advancing the art and science of neurology, and thereby promoting the best possible care for patients with neurological disorders A Celebration of the First 50 Years of the American Academy of Neurology Neurology 1957;7:415-426 In the past three years five children with a progressive demyelinating disease of the central nervous system have been investigated in three different families. This disorder is described as the metachromatic form of diffuse cerebral sclerosis (metachromatic leucoencephalopathy). The scope of the present report will be largely limited to a description of the distinctive findings which all five patients have had on urine sediment examination. These reflect directly the pathologic changes found in the kidneys in this disorder.1 These urine findings, properly interpreted, have permitted a diagnosis of this demyelinating disease of the central nervous system for the first time during life. A brief and introductory review of this disorder and of this case material is pertinent here. Clinical, pathologic, control, and other details on these patients are discussed in other communications. In 1910 Alzheimer and Nissl first commented upon metachromatic staining in the central nervous system in a case of diffuse sclerosis.2,3 Since then, some 18 cases have been reported, only two of them from this continent.4,5 In this form of the disorder, admixed with the expected diffuse demyelination, gliosis, and axonal loss, are quantities of unusual abnormal materials. These materials occur in granular clumps which stain shades of red with blue basic aniline dyes. They stain a color other than that of the dye used, that is, metachromatically. Accordingly, this form of diffuse sclerosis is known as the metachromatic form. A discussion of the general topic of diffuse sclerosis is given elsewhere.6,7 These granular structures characteristically do not stain for neutral fats to any …

Urticaria pigmentosa (large nodular type); report of a case.

URTICARIA pigmentosa of the large nodular type is of sufficient rarity to cause diagnostic problems. The condition may remain undiagnosed unless a specimen is removed and examined microscopically after the tissue has been stained with one of the basic aniline dyes. Finnerud1and Little2in excellent reviews stated that in approximately 10 per cent of cases of urticaria pigmentosa the lesions are of the nodular type. However, the occurrence of large tumors in urticaria pigmentosa similar to those observed in our case is apparently unrecognized. We wish to report such a case and to comment briefly on the prognosis and the association of heparin with the mast cells. REPORT OF A CASE A 21 month old American boy of Syrian parentage was seen at the Mayo Clinic in November 1946. Since birth this patient had been normal except for brown oval and round nodules on the neck,

Further Investigations on the Blood-Brain-Barrier

Summary and Conclusions After intravenous injection into guinea pigs weighing 300 grams all basic aniline dyes with the exception of safranine stain the brain in amounts ranging from 1 to 7 mgm. Some acid dyes (acid fuchsin, orange, bordeaux, eosin, uranine) do not stain the brain at all in the available amounts. Some others (trypan blue, congo red, water blue, alizarin blue-S, indigo di- and tetrasulphonate) stain in amounts varying from 20 to 80 mgm. The difference between basic and acid dyes is partly due to a difference in their affinity for brain tissue. The latter was tested by determining the minimal staining dose in vitro (Cv). In addition the cerebral capillaries are more permeable to basic than to acid dyes. This permeability can be determined by the ratio between the minimal staining concentrations in vivo and in vitro (CB/Cv). The permeability of the cerebral capillaries to dyes is independent of their chemical constitution, their size and their lipoid solubility. It merely depends on their electrical charge. Staphylococcus toxin acts rapidly without any incubation period. It is unable to pass the blood-brain-barrier. Staphylococcus toxin carries a negative charge at the pH of the blood. The isoelectric point is in in the neighbourhood of pH 6.2. A special method has been devised to compare the ζ-potentials of toxins. The capacity of toxins to pass the capillary system is correlated with their ζ-potentials. Tentatively, a theory is advanced according to which the selective permeability of the capillary system in general and the blood-brain-barrier in particular is due to an irreciprocal permeability.

Vital granularity of erythrocytes

When unfixed blood smears are stained with basic aniline dyes (for example, Brillantkresylblau), a blue granular-filamentous substance becomes visible in some erythrocytes.

The staining of fat with basic aniline dyes

The Journal of Pathology and BacteriologyVolume 11, Issue 4 p. 415-420 Article The staining of fat with basic aniline dyes† J. Lorrain Smith, J. Lorrain Smith Pathological Laboratory, University of Manchester Professor of Pathology, University of Manchester.Search for more papers by this author J. Lorrain Smith, J. Lorrain Smith Pathological Laboratory, University of Manchester Professor of Pathology, University of Manchester.Search for more papers by this author First published: 1906 https://doi.org/10.1002/path.1700110407Citations: 15 † Read at the first meeting of the Pathological Society of Great Britain and Ireland, held in Manchester, 14th July 1906. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume11, Issue41906Pages 415-420 RelatedInformation