Acridine basicity

In this work hybrid method is suggested to determine anionic surfactants in waters. It is based on preconcentration of anionic surfactants as their ion associates with cationic dyes on the membrane filter and measurement of colour intensity by solid-phase spectrophotometry method. Effect of different basic dyes, nature and hydrophobicity of anionic surfactants, size of membrane filter pores, filtration rate on sensitivity of their determination was studied. Various cationic dyes, such as Methylene Blue, Crystal Violet, Malachite Green, Rhodamine 6G, Safranin T, Acridine Yellow were used as counter ions. The difference in reflection between the blank and the sample was significant when Crystal Violet or Rhodamine 6G or Acridine Yellow were used. 

In the hydrolysis of acridine antimalarials, the role of the protonated species of the substrate appeared to be important even in aqueous solution buffered at pH 7.3, i.e., under conditions of physiological interest.Moreover, out of the three possible modes of reaction mathematically possible (H3O+-HB, HgO-f BH+, and OH -f BH2+, where B is the basic substrate) the one not involving the protonated substrate can be ruled out on structural grounds. 

Dipping solution Dissolve 0.02 g acridine orange (Basic Orange 14, C.I. 46005) in 100 ml ethanol [3]. 

It had been found that if bacteria are stained with acridine orange and examined under fluorescent microscopy, viable, as dishnct from dead, cells fluoresce with an orange-led hue. This basic observation has been adapted to an ingenious method of determining bacterial content and may be completed within 1 hour. 

The pH indicator shows the acid or basic properties of sample molecnles. Commonly used for acid indicating are solutions of bromocresol green (20 mg dissolved in 10 ml of ethanol combined with 1 ml of 0.1-molar aqueous NaOH) or bromophenol blue (20 mg dissolved in 10 ml of ethanol, pH-adjusted with 0.1-molar NaOH or 0.2% aqneous citric acid). In the presence of acids, 2,6-dichloroindophenol (40 mg dissolved in 100 ml of ethanol) changes the color from blue to red. The fluorescent dye acridine orange (20 mg dissolved in 100 ml of ethanol) changes pH-dependently the color of its flnorescence from yellow-green to yellow. 

Identification of dyes on dyed textiles is traditionally carried out by destructive techniques [493], TLC is an outstanding technique for identification of extracted dyestuffs and examination of inks. Figure 4.9 shows HPTLC/SERRS analysis of acridine orange [492], Wright et al. [494] have described a simple and rapid TLC-videodensitometric method for in situ quantification of lower halogenated subsidiary colours (LHSC) in multiple dye samples. The results obtained by this method were compared with those obtained by an indirect TLC-spectrophotometric method and those from HPLC. The total time for the TLC-videodensitometric assay of five standards and four samples applied to each plate was less than 45 min. The method is applicable for use in routine batch-certification analysis. Loger et al. [495,496] have chromatographed 19 basic dyes for PAN fibres on alumina on thin-layer with ethanol-water (5 2) and another 11 dyes on silica gel G with pyridine-water... 

Scheme 52 explains the [(Cp )Rh(MeCN)3]2+-assisted regioselective hydrogenation of pyridines, benzoquinolines, acridines as well as indoles and benzothiophene.258 The relative hydrogenation rates were attributed to both electronic and steric effects, the rate generally decreasing with increasing basicity and steric hindrance at the nitrogen atom. 

Under basic conditions, A -acridinylmethyl-substituted thiourea 449 placed in the presence of bromoacetonitrile gave rise to the unexpected formation of the spiro[dihydro-acridine-9(10//),2 -(2, 7 -dihydro-3 //-imidazo[l,2-c]thiazol-5 -ylidene-/>-nitrophenyl)amine] 450 in 67% yield. The reaction involved displacement of the bromine atom of... 

The distribution of each chemical type between the major application groups of colorants is far from uniform (Table 1.1). Stilbene and thiazole dyes are almost invariably direct dyes, also containing one or more azo groups. Acridines and methines are usually basic dyes,... 

Acridine derivatives, such as acriflavine (1.31), can be regarded as relatives of the diphenylmethane class in which the two benzene nuclei are linked by nitrogen to form a pyridine ring. Their insignificance nowadays resembles that of their relatives, but they were formerly useful mainly as orange or yellow basic dyes [28]. 

Many brilliantly coloured and tinctorially strong basic dyes for silk and tannin-mordanted cotton were developed in the early decades of the synthetic dye industry. Most of these belonged to the acridine, azine, oxazine, triarylmethane, xanthene and related chemical classes their molecules are usually characterised by one delocalised positive charge. Thus in crystal violet (1.29) the cationic charge is shared between the three equivalent methylated p-amino nitrogen atoms. A few of these traditional basic dyes are still of some interest in the dyeing of acrylic fibres, notably as components of cheap mixture navies and blacks, but many modified basic dyes were introduced from the 1950s onwards for acrylic and modacrylic fibres, as well as for basic-dyeable variants of nylon and polyester [44] ... 

Kido et al. [6] determined basic organic compounds such as quinoline, acridine, aza-fluorene, and their N-oxides in marine sediments found in an industrial area. The sediments were extracted with benzene by using a continuous extractor for 12h. Hydrochloric acid solution (IN) was added to the benzene extracts, and the mixture was shaken for 5min the acid layer separated from the benzene layer was made alkaline by the addition of sodium hydroxide, and the alkaline aqueous solution was extracted with diethyl ether the ether extracts were then dehydrated with anhydrous sodium sulphate and concentrated with a Kuderna-Danish evaporator. The concentrations were separated and analysed by gas chromatography-mass spectrometry and gas chromatography high-resolution mass spectrometry. 

Nitrogen heteroaromatics are expected to be useful probases. The cathodic reduction of phenazine, (31), resembles closely that of (29a) [70,71], and the kinetic basicity of (31) is comparable to that of (29a) [54]. However, application of (31) as a PB in electrosynthesis has not been reported, and there is only a single report concerning the use of the radical anion of acridine, (32), as an EGB [72]. 

Pyridine, the quinoline and acridine AT-oxides readily form salts e.g. hydrochlorides (27) and picrates) which have been used for their characterization. Basic salts of the type (ArNO)2HX are also known the structure (28) is indicated for 2-picoline 1-oxide hemihydro-bromide based on IR evidence. A list of these salts has been compiled (b-71MI20500). 

A number of other heterocycllcs have been similarly studied and shown by H nmr, to produce quaternary ammonium salts with living polyTHF.2- Moreover, their rates of reaction are a direct function of their basicities, the following order of reactivities being observed ethyl pyridine > pyridine > isoquinoline > quinoline > acridine. Aliphatic tertiary amines also react in the same way the order of reactivities was found to be triethylame > tributylamlne > dlethylanillne. In all cases studied, the quaternary ammonium salt once formed did not exchange with any excess oxonium lone. 

C. Interpretation of Equilibrium Data For pyridine, quinoline, isoquinoline, and acridine, the differences in the 7r-electronic energies of the protonated form and the free base have been calculated at several levels of sophistication, from the HMO method to the Cl SCF method.191 The A W values obtained are linearly interrelated, which supports the view that the HMO data are meaningful. In this connection, considerable attention has been paid to the role of solvation energies in acido-basic equilibria.161... 

The reactions of the 4-halopyridines parallel those of the corresponding 2-isomers, with the exception that 4-halopyridines polymerize much more readily (e.g. to 903) because the pyridine nitrogen atom is not sterically hindered and is more basic (cf. Section 3.2.1.3.4). As expected, the chlorine atom in the 1-position of 1,3-dichloroisoquinoline is more reactive than that in the 3-position, thus, mild treatment with sodium ethoxide gives (904). Halogens in the 9-position of acridine are more reactive, e.g. (906) — (90S), (907). 

The o values of rings annelated to pyridine in systems such as quinoline, isoquinoline, benzoquinolines, acridine, and phenanthridine and determined by the basicity of the ring nitrogen atom are predicted186 and found to be small.33,34 This is an important point stressed and elucidated previously,181 and demonstrating the validity of the basic assumptions of the Hammett equation. 

A number of studies have been directed specifically at the acridine nucleus. The effect of substituents in the 9-position in acridine (V-oxides on Rf values for thin-layer chromatography (TLC) is measured by ap,198 and there is also a relation between this parameter and the N—O stretching frequencies. The effect of substituents on the basicity of acridine and the possibility of amine-ketimine tautomerism in 9-aminoacridines have been evaluated, taking quinoline as a model... 

---