Acridines, formation

Pyrolysis of the Mannich base (109) derived from 2-naphthol leads to generation of a quinone methide which when trapped with an aromatic amine leads to benz[a]acridines (0. Bilgic and D.W. Young, J. chem. Soc. Perkin I, 1980, 1233). Thus, aniline yields the parent compound together with 7,12-dihydrobenz[a]acridine. Formation of the dihydro compound appears to be variable for whereas /7-metlylaniline and o-anisidine yield only... 

Photopolymerization reactions are widely used for printing and photoresist appHcations (55). Spectral sensitization of cationic polymerization has utilized electron transfer from heteroaromatics, ketones, or dyes to initiators like iodonium or sulfonium salts (60). However, sensitized free-radical polymerization has been the main technology of choice (55). Spectral sensitizers over the wavelength region 300—700 nm are effective. AcryUc monomer polymerization, for example, is sensitized by xanthene, thiazine, acridine, cyanine, and merocyanine dyes. The required free-radical formation via these dyes may be achieved by hydrogen atom-transfer, electron-transfer, or exciplex formation with other initiator components of the photopolymer system. 

Methyl propiolate and pyridine give a rather unstable 2 1 molar adduct which is the 1,2-dihydropyridine (112). The reaction sequence proposed to account for its formation is identical in principle to a similar scheme proposed earlier in the acridine series (Section II,A,2) and is also supported by the observation that the 1-benzoyl-pyridinium cation with the phenylacetylide anion yields (113). ... 

A detailed study of the dehydrogenation of 10.1 l-dihydro-5//-benz[6,/]azcpinc (47) over metal oxides at 550 C revealed that cobalt(II) oxide, iron(III) oxide and manganese(III) oxide are effective catalysts (yields 30-40%), but formation of 5//-dibenz[7),/]azepinc (48) is accompanied by ring contraction of the dihydro compound to 9-methylacridine and acridine in 3-20 % yield.111 In contrast, tin(IV) oxide, zinc(II) oxide. chromium(III) oxide, cerium(IV) oxide and magnesium oxide arc less-effective catalysts (7-14% yield) but provide pure 5H-dibenz[b,/]azepine. On the basis of these results, optimum conditions (83 88% selectivity 94-98 % yield) for the formation of the dibenzazepine are proposed which employ a K2CO,/ Mn203/Sn02/Mg0 catalyst (1 7 3 10) at 550 C. 

A highly sensitive method for the determination of anionic surfactants, particularly sodium dodecyl sulfate, has been described [275]. The method is based on the formation of fluorescent ionic complexes of the anionic surfactant with acridine red and acridine yellow. The complexes are extracted with dichloro-... 

The aromatic spacer group of the model receptors prevent the formation of intramolecular hydrogen bonds between the opposing carboxyls yet these functions are ideally positioned for intermolecular hydrogen bonds of the sort indicated in 32. The acridine derivatives do indeed form stoichiometric complexes with oxalic, malonic (and C-substituted malonic acids) as well as maleic and phthalic acids, Fumaric, succinic or glutaric acids did not form such complexes. Though protonation appears to be a necessary element in the recognition of these diacids, the receptor has more to... 

In polar solvents, the structure of the acridine 13 involves some zwitterionic character 13 a [Eq. (7)] and the interior of the cleft becomes an intensely polar microenvironment. On the periphery of the molecule a heavy lipophilic coating is provided by the hydrocarbon skeleton and methyl groups. A third domain, the large, flat aromatic surface is exposed by the acridine spacer unit. This unusual combination of ionic, hydrophobic and stacking opportunities endows these molecules with the ability to interact with the zwitterionic forms of amino acids which exist at neutral pH 24). For example, the acridine diacids can extract zwitterionic phenylalanine from water into chloroform, andNMR evidence indicates the formation of 2 1 complexes 39 such as were previously described for other P-phenyl-ethylammonium salts. Similar behavior is seen with tryptophan 40 and tyrosine methyl ether 41. The structures lacking well-placed aromatics such as leucine or methionine are not extracted to measureable degrees under these conditions. 

Another way in which Pt could bind to DNA is through the formation of intercalation compounds. The parallel here is with the hydrocarbon carcinogens and the nucleic acid stains, the acridines. It has been shown that metal chelates will form this same type of jt-complex. For example, palladium oxinate will form exactly the same type of -complexes as anthracene (88). 

Anthracene has also been used as an acceptor (Fig. 10). In solution, 26 emits a single fluorescence band that is somewhat structured in nonpolar solvents and becomes broad and structureless with increasing polarity [58]. The strongly hindered molecule 27 also exhibits a similar behavior, but its absorption spectrum is better structured [59]. The rate of formation of a charge transfer state is higher for 27 than for 26. Based on this observation, it appears that the twist around the anthryl-phenyl C-C bond plays a significant role in the fluorescence profile of the probes [60]. Acridines, such as 28, behave similarly to anthracene except that acridine is a better electron acceptor [61]. 

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... 

Products isolated from the thermal fragmentation of A-arylbenzamide oximes and A-arylbenzamide O-phenylsulfonyl oximes have been accounted for by invoking a free-radical mechanism which is initiated by the preferential homolysis of the N-O bond." Time-resolved IR spectroscopy has revealed that photolysis of A, A -diphenyl-l,5-dihydroxy-9,10-anthraquinone diimine affords acridine-condensed aromatic products via excited-state intramolecular proton transfer." The absolute and relative rates of thermal rearrangements of substituted benzyl isocyanides have been measured,and it has been found that the relative rates are independent of temperature and exhibit excellent Hammett correlations. Thionitrosoarene (25), thought to be generated by desulfurization of the stable A-thiosulfinylaniline (24), has been established" " as an intermediate in the formation of 3,3a-dihydro-2,l-benzisothiazole (26) from o-alkylthionitrosoarene (24). 

Quinoline 1-oxide undergoes nucleophilic attack by ozone to yield a hydroxamic acid (128), and 40% of the starting iV-oxide is recovered (Scheme 74). When an excess of ozone is employed the aldehydes (129) and (130) are obtained. Formation of these products has been attributed to electrophilic attack by ozone rather than further oxidation of (128), because in a separate experiment (128) yielded carbostyril on treatment with ozone. Isoquinoline 2-oxide yields 2-hydroxyisoquinolin-l-one, and acridine 10-oxide gives 10-hydroxyacridone and acridone in a similar manner to the above. Likewise, phenanthridine 5-oxide affords mainly 5-hydroxyphenanthridone. Quinoline 1-oxide undergoes oxidation by lead tetraacetate as shown (Scheme 75). 

Pyridine reacts with sodium hydrazide in the presence of hydrazine to yield 2-hydrazinopyridine in the absence of free hydrazine a hydrazo compound is formed (Scheme 88) (64AG(E)342). A difference between hydrazination and amination is the formation of 1,4-adducts which cannot be rearomatized even on heating. This is reflected in the behaviour of quinoline, which gives only a 0.5% yield of a -hydrazino product, whereas 4-methylquino-line is hydrazinated in 76% yield (64AG(E)342). Acridine behaves differently with sodium hydrazide/hydrazine, 9,10-dihydroacridine is formed almost quantitatively, but reaction in the absence of hydrazine yields 9-aminoacridine (65%). An even higher yield of 9-amino-acridine is obtained when sodium Af.AC-dimethylhydrazide is used (Scheme 89). Good evidence for intermediacy of (151) comes from the isolation of (152) on hydrolysis of (151). 

In the thermodynamic study of duplex formation, a variety of complementary pairs of relatively simple, well-defined oligonucleotides are employed, " while the intercalation thermodynamics was examined with more complex or natural DNA duplexes. " Typical intercalating agents examined are acridine orange, acriflabine, actinomycin, daunomycin, ethidium bro-... 

Formation of the photo peroxide of azanthracenes has been studied extensively. Acridine and 9-phenylacridine seem not to form photo-peroxides,63 but from 2-phenyl-l-azanthracene07,66 a labile peroxide is obtained. The benzacridines photoperoxides are rapidly transformed into... 

The interaction between pyridine and organolithium compounds in benzene was first reported by Ziegler and Zeiser129 and was attributed to the formation of 1 1 adducts. Indirect evidence for intermediates of this kind was based on the formation of dihydropyridines by treatment of the reaction mixture with water. More definite evidence was obtained with quinoline, isoquinoline, and acridine.130 Phenyllithium reacts quantitatively with quinoline in ether to yield an adduct as a yellow powder that can be recrystallized. In order to define the site of attachment, the adducts were hydrolyzed to dihydro derivatives and the latter dehydrogenated. Because this treatment leads mainly to 2-phenyIquinoIine and l-phenylisoquinoline from quinoline and isoquinoline, respectively, the related adducts can be assumed to have structures 80 and 81. Isolation and characterization of the dihydro derivatives have been carried out, as well as in the case of the reaction of acridine with phenyllithium. 

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