Acridine, halogenation

Acridine, halogenation, 59, 295 Acridine A-oxide, halogenation, 59, 295 Acridine, 9-benzyl-, nitration, 58, 251 Acridine, 9-phenyl-, nitration, 58, 251 Acridin-9(10//)-ones, see Acridones Acridizinium ion, see... 

A few studies on solvolyses by alcohols and by water are available. The hydrolyses studied include displacement of alkylamino groups from acridine antimalarials and of halogen from other systems. In all cases, these reactions appeared to be first-order in the heterocyclic substrate. By a detailed examination of the acid hydrolysis of 2-halogeno-5-nitropyridine, Reinheimer et al. have shown that the reaction rate varies as the fourth power of the activity of water, providing direct evidence that the only reactive nucleophile is neutral water, as expected. 

Halogenations of quinoline, isoquinoline, acridine, and phenanthridine will be discussed here. Reaction usually occurs in a homocyclic fused ring rather than in the 7r-deficient pyridine moiety, especially in acidic media. Relatively mild conditions suffice, but under more vigorous regimes radical involvement can result in heteroring halogenation. Substituents are able to modify reactivity and regiochemistry. 

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... 

Second only to sulfur-based systems, nitrogen complexes are relatively well represented in the structural literature with 41 complexes reported. Of these, 25 are with I2 as the electron acceptor, 11 are with the interhalogen IC1, three are with Br2, and two are with IBr. As expected, in every case the halogen bond forms between the nitrogen and the softest halogen atom, i.e., iodine, in all of the complexes except those with dibromine. Most N I2 complexes, and all N Br2, N IBr, and N IC1 complexes are simple adducts, mode A. Exceptions for the diiodine complexes include bridging mode (B) observed for diazines, such as pyrazine [86], tetramethylpyrazine [86], phenazine, and quinoxaline [87], and for 9-chloroacridine [89] and the 1 1 complex of diiodine with hexamethylenetetramine [144] and amphoteric bridging mode (BA) observed for 2,2 -bipyridine [85], acridine [89], 9-chloroacridine [89], and 2,3,5,6-tetra-2/-pyridylpyrazine [91]. The occurrence of both B and BA complexes with 9-chloroacridine, and of B and A complexes and an... 

Although chlorination, bromination and iodination of thiophenes by polyhalide salts require forcing conditions with the addition of zinc chloride [52], halogenation of acridine and acridone has been recorded to yield both 3-halo and 3,7-dihalo derivatives under relatively mild reaction conditions [53], However, whereas chloro-, bromo- and iodo-compounds are readily obtained from acridone, acridine only forms the bromo derivatives, as it produces stable complexes with the dichloroiodate and tetrachloroiodate salts [53]. 

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 halogen atom of 7-chloro l,2,3.4-tetrahydrobenz [c]acridine is prone to nucleophilic displacement, as expected of a y-halogenopyridine system. Ready hydrolysis yields the 7-hydroxy compound and sodiomalononitrile affords the dicyanomethyl derivative both products exist as the keto-tautomers (B.V. Lap et at, 2. heterocyclic Chem., 1983, 20, 281). 

To date, the organic substances studied via ONP have typically been planar, aromatic molecules in pure or mixed crystalline form. While ONP was first demonstrated in pure anthracene, the most commonly-studied systems for ONP (and related OEP) experiments over the years have been fluorene doped with acridine," " phenanthrene, ° phenazine, ° and anthracene," ° as well as naphthalene and p-terphenyl doped with pentacene. ° ° Other investigations of ONP have included studies of anthracene doped withphenazine, tetracyanobenzene," and tetracene, as well as acridine, ° dibromodiphenylether with benzophenone" and dichlorobenzophenone, and various halogenated benzenes. ... 

The retention characteristics of 29 aza-arenes (e.g., pyridine, acridine, quinoline, benz[a]acridine, and numerous substituted analogs) were studied on a diol column using a 97.5/2.5 iso-octane/ethanol mobile phase [611]. Dimethylbenz[a]acridine was least retained k < 3) and indole had the greatest retention (k > 9). The study also worked with 29 phenols (e.g., numerous alkyl-substituted phenols, nitrophenols, and halogenated phenols). They were studied in detail on the diol column using a 50/50 iso-octane/dichloromethane mobile phase. Appropriate selection of solvent composition provided baseline resolution of isomeric groups (e.g., dimethylphenols using hexane/ethyl acetate). 

Gao HY, Zhao XR, Wang H, Pang X, Jin WJ (2013) Cocrystal assembled by 1,2-diiodotetrailuorobenzene and acridine via C-I—N halogen bond and x-hole - F bonds. Chin J Chem 31 1279-1284... 

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