Aniline based

These chlorozincates must not be confused with the non-ionic compounds which quinoline and aniline bases give with neutral zinc chloride the latter have the formulae [(C,H7N)2ZnClt] and [(C,H7N)tZnCl ] respectively, and both are only slightly soluble in water. 

Symmetrical pyrrole- and phloroglucinol-based oxo-squaraines 2 and 3 were first synthesized by Treibs and Jacob in 1965 [43, 44] and aniline-based squaraines 4... 

Fig. 6 Synthesis of symmetrical and unsymmetrical aniline-based oxo-squaraines...

Symmetrical, aniline-based, and aromatic oxo-squaraines are synthesized via a one-step reaction by heating two equivalents of the appropriate /V,/V-dialkylaniline or other reactive aromatic or heteroaromatic derivatives with squaric acid (Fig. 6) [38, 41]. Unsymmetrical aniline-type squaraines can be synthesized in two steps first one component is reacted with squaric acid dichloride to yield a mono-squaraine intermediate, which in a subsequent step is then reacted with the second component to yield the unsymmetrical squaraine dye [53]. 

A series of unsymmetrical oxo-squaraines 7, containing both heterocyclic and aniline-based end-groups, was synthesized and their absorption spectra were investigated [61]. Some of these dyes, absorbing between 680-820 nm with high molar... 

The aniline-based squaraines 4 with hydroxyalkyl, carboxypropyl, and ethylene glycol groups exhibit absorption maxima between 640-649 nm (eM = 100,000-300,000 M 1cm x) and emission maxima between 663 and 675 nm in aqueous solutions... 

The quantum yields are 0.15-0.21 in ethanol and 0.01-0.02 in an aqueous medium, but in micelles, the quantum yields are five to tenfold increased. The aggregation of these dyes was studied in [53]. The amphiphilic squaraines 4 combine favorable photophysical properties and good solubility in aqueous media and in addition interact efficiently with micelles, and therefore have the potential to be used as NIR fluorescent sensors. However, our own investigations show that aniline-based squaraines lack chemical and photochemical stability when compared to oxo-squaraines with heterocyclic end-groups. 

Aniline-based amino-squaraines 40 can be obtained via reduction of oxo-squar-aines with NaBFLj in methanol followed by substitution and oxidation with chlor-anil or lead dioxide [106] (Fig. 11). 

Bosch LI, Mahon MF, James TD (2004) The B-N bond controls the balance between locally excited (LE) and twisted internal charge transfer (TICT) states observed for aniline based fluorescent saccharide sensors. Tetrahedron Lett 45(13) 2859-2862... 

Some heterocyclic nucleophiles may also be successfully employed in these cyclization reactions (Schemes 25 and 26) [131]. In contrast, no cyclization was observed in an aniline-based system (Scheme 27), which reflects the reduced nucleophilicity of the aniline nitrogen [142],... 

Scheme 27 Absence of cyclization in an aniline-based system...

The anlhracene-conVd n ng tetralactam macrocycles 16a and 16b were found to have an extremely high affinity for aniline-based squaraine dyes in chloroform [56]. 

A variety of hydrophobic and hydrophilic squaraine rotaxane probes and labels such as 21a-21e c Rp and 22a-22e c Rp, containing reactive carboxylic functionalities and hydrophilic sulfo groups, are disclosed in a recent patent application [60]. It was shown that not only aniline-based squaraines 21a-21e but also heterocyclic squaraines 22a-22e can form stable pseudorotaxane complexes. The indo-lenine-based squaraine 22a forms rotaxane 22a C Rp. Importantly, also the sulfonated squaraine 22b could be successfully encapsulated in a Leigh-type, phenylene-based, tetralactam macrocycle to yield the water-soluble rotaxane 22b C Rp. Quatemized, indolenme-based squaraines do not form pseudorotaxanes probably because of sterical hindrance caused by /V-alkyl and 3,3 -dimethyl groups. On the other hand, quatemized benzothiazole (22c) and benzoselenazole (22d) squaraines could be embedded in a Leigh-type macrocycle to yield rotaxanes 22c C Rp and 22d C Rp, respectively. The hydrophilic, mono-reactive rotaxane 22e-NHS C Rp based on asymmetric squaraine, synthesized by a cross-reaction of squaric acid with the two different indolenines, was also obtained. 

It turned out that only the compounds listed on the right side of the scheme, namely those containing one nitrogen atom, are reduced to the aniline base by fermenting yeast no distinct reduction of the azo derivatives was observed. Whether this would be possible by altering the experimental conditions cannot be stated offhand (see p. 100). 

In the initial phases of the analytical method development a Waters Associates C-jq y-Bondapak column was used. With certain dyes, such as C.I. Direct Black 38, aniline is used as a terminal group (Figure 1). This column caused the benzidine peak of the reduced dye to obscure a peak due to aniline. If these two compounds were not resolved, the method could not differentiate between benzidine-based and aniline-based dyes. This problem was removed by use of the Waters Radial Compression Module Model RCM 100 with a Radial Pak A cartridge. 

The use of aniline in rubber chemicals will closely track the Gross Domestic Product growth in the United States, while its use in agricultural chemicals is expected to slowly decline. Aniline-based dyes and pigments are forecast to have little growth255. 

Pyrimidine, (Y), triazines, and aniline-based bradykinin receptor antagonists, (Y), prepared by Olmeyer (4) were effective in treating inflammation, pain, and multiple sclerosis. 

Figure 64 Common oxidation states of poly aniline (base forms are shown). (From Ref. 265.)...

The following postmortem tissue concentrations were reported in a fatality attributed to ingestion of an aniline-based ink blood 6.3 pg/ml, liver 20 pg/g, urine 40 pg/ml (J. S. Oliver and D. J. Williams, ibid.). 

The compound should be white or pale yellow. It should melt at 2 to 4 and should yield practically no insoluble residue in ether or alcohol. It should also give a clear solution in pure sulphuric acid (a blue colour indicates the presence of nitrate). It should have no unpleasant smell. Aniline bases should be present only in traces (0 001 per cent.). These may be tested for by bleaching powder. 

Beller and coworkers recently reported a new strategy for the synthesis of poly-substituted anilines based on a three-component-coupling reaction and a domino deprotec-tion/aromatization reaction (equation l)44. A mixture of O-benzyl carbamate, p-toluene-sulfonic acid, aldehyde, AC2O and dienophile in /V-rnclhy I pyrrol idone was allowed to react for 24 h at 120 °C, followed by Pd/C catalyzed dehydrogenation in triglyme at 140 °C. A variety of tri-, tetra- and penta-substituted anilines were efficiently created by this domino process. 

Fig. 105. Construction and response curve of an organelle electrode for aniline based on immobilized liver microsomes. (Redrawn from Mohr et al., 1984).

Cases of severe and nearly lethal toxic effects after dermal exposure to aniline-based dyes have been reported as early as 1886. These cases have involved mainly infants exposed to dye-stamped diapers and persons wearing freshly dyed shoes. The resulting condition was often termed "nitrobenzene poisoning", even though exposure to nitrobenzene did not necessarily occur. Several conclusions and generalizations about the dermal absorption and toxic effects of nitrobenzene, especially in infants, seem to have been based on these studies which should more appropriately be considered as part of the data base for aniline. 

A special aromatic aminic polyol was obtained by propoxylation or ethoxylation of aniline [7]. These diols were used sometimes as chain extenders in elastomers and in coatings. The disadvantage of these aniline-based diols is the fact that at a ratio of 2 mols of alkylene oxide (PO, especially EO) they become solid at room temperature, by crystallisation ... 

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