Acridine oxidation

Chemiluminescent labels, in which the luminescence is generated by a chemical oxidation step, and bioluminescent labels, where the energy for light emission is produced by an enzyme-substrate reaction, are additional labeling types (39,42). Luminol [521 -31 -3] CgHyN202, and acridine [260-94-6] C H N, derivatives are often used as chemiluminescent labels. 

Acridine, 9,10-dihydro-9,9-dimethyl-as antidepressant, 1, 169 Acridine, 9-formyl-synthesis, 2, 507 Acridine, 3-hydroxy-formylation, 2, 322 Acridine, 9-hydroxy-N-oxide... 

Acridine-9-thione alkylation, 2, 357 oxidation, 2, 357 tautomerism, 2, 356 9-Acridinium bromide reactions... 

Benz[a]acridine-3,4-diol, 3,4-dihydro-oxidation, 2, 184-185 Benz[c]acridine-3,4-diol, 3,4-dihydro-oxidation, 2, 185 Benzacri dines synthesis... 

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. 

Nitroso-5//-dibenz[/>,/]azepine (9, R = NO) is relatively stable to photolysis under argon, whereas in benzene solution in the presence of oxygen, irradiation induces an oxidative Fischer -Hepp-type rearrangement to 2-nitro-5//-dibenz[6,/]azepinc (10, R = N02), accompanied by ring contraction to acridine-9-carbaldehyde184 (see also Section 3.2.2.4.). 

Oxidation of 5//-dibenz[7>,/]azepine (12) with Fremy s salt [ON(S03K)2] yields a mixture of acridine-9-carbaldehyde (13) and 2//-dibenz[A,/]azepin-2-one (14).215 The dibenzazepin-2-one 14 is also obtained in 46% yield with bis(trifluoroacetoxy)pentafluoroiodobenzene [PhI(OCOCF3)2] in acetonitrile as the oxidant.221... 

Acridine-9-carbaldehyde (24%) is one of several products formed from the oxidation of 5//-dibenz[A/]azepine with tert-butyl hypochlorite in dichloromethane at — 70 C.229 The reaction is even more complex in the presence of silver(I) trifluoroacetate, and an analysis of the reaction mixture by GC-MS techniques reveals the presence of eleven products, the major ones being acridine (37%), an unidentified 5//-dibenz[/ ,/]azepinecarbaldehyde (23%) and acridine-9-carbaldehyde (9 %). 

The first reported derivative of 1,2-oxazepine was dibenz[f,/][l,2]oxazepine-ll-carbonitrile (3 a). This, together with small amounts of compounds 4 and 5, is formed when acridine-9-carbonitrile 10-oxide (la) is irradiated with UV light,6,7 It is likely that the reaction proceeds by way of the oxaziridine valence tautomer 2a, which, however, was not detected.7 Photo-isomcrization of 9-chloroacridine 10-oxide (lb) yields the 11-chlorodibenzoxazepine 3b.6,7... 

Acridine-9-carbonitrile 10-oxide (la 3.00g, 13.6 mmol) in benzene (1.8 L) in a quartz immersion well was irradiated for 3 h with a Hanovia high-pressure 450-W Hg lamp equipped with a Pyrex filter. The resulting solution was evaporated under reduced pressure and the residue was extracted with pentane (3 x 50 mL). The combined extracts were evaporated under reduced pressure at 20 C to give orange crystals yield 1.8 g (60%) mp 105-109 C (Et20/pentane). 

Dibenz[c,/][1,2]oxazcpine-ll-carbonitrile isomerizes to the TV-oxide acridine-9-carbonitrile 10-oxide on heating in aprotic solvents. Attempted chromatography on silica gel or alumina columns gave a mixture of the oxepino[2,3-6]quinolinecarbonitrile 2, the oxoazepinoindolecarbo-nitrile 3 and the benzo[c]-2-aza-l,6-oxa[10]annulenecarbonitrile 4. Only these types of compounds were isolated when 2,7-dimethylacridine 10-oxide was irradiated.6... 

The rate constants for these relatively short range hole transfer reactions generally decrease exponentially with distance. Yet, characterizing these DNA-mediated reactions with the parameter (3 is a simplification and is certainly inappropriate in cases where the Frank-Condon factor varies with distance (such as has been observed for the acridine photooxidant). Keeping these limitations in mind, however, /i-values for DNA-mediated hole transfer of -0.6-0.7 A-1 have been suggested using several different oxidant-DNA assemblies (Ap, St, Ap radical cation). 

When acridane 1 is oxidized by dibenzoyl peroxide in propanol/ water in acid or neutral medium, there occurs chemiluminescence whose emission spectrum matches the fluorescence spectrum of acridinium cation (protonated acridine) 2. As radical scavengers have no influence... 

Similar mechanisms are suggested for the chemiluminescence of 9-formylacridine 92, 9-formyl- 10-methylacridinium methosulfate 95 9-benzoylacridine 93 and 9(4-nitrobenzoyl)-acridine 94 142> which occurs on oxidation of these compounds with base and oxygen in DMSO. 

Several N-methyl-9-acridinecarboxylic acid derivatives (e.g., 10-methyl-9-acridinecarboxylic chloride and esters derived therefrom [39]) are chemiluminescent in alkaline aqueous solutions (but not in aprotic solvents). The emission is similar to that seen in the CL of lucigenin and the ultimate product of the reaction is N-methylacridone, leading to the conclusion that the lowest excited singlet state of N-methylacridone is the emitting species [40], In the case of the N-methyl-9-acridinecarboxylates the critical intermediate is believed to be either a linear peroxide [41, 42] or a dioxetanone [43, 44], Reduced acridines (acridanes) such as N-methyl-9-bis (alkoxy) methylacridan [45] also emit N-methylacridone-like CL when oxidized in alkaline, aqueous solutions. Presumably an early step in the oxidation process aromatizes the acridan ring. 

Mesitonitrile oxide and acridine (1 2 ratio) react site- and regioselectively to give mono-cycloadduct 127. The reaction of the same reagents in a 10 1 ratio afforded the mono-cycloadduct 127, and the bis-cycloadduct 128 with the opposite regiochemistry to that of the mono-cycloadduct (288). 

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. 

During photolysis of acridine A-oxides 54, two isomeric indolotro-pones (56a,b) are formed, among other products (Scheme 14 75CL401, 75CPB2818 79T1273). As confirmed by UV spectra, the isomerization of 54 passes through intermediate 55. 

Photochemical hydroxyalkylation has been carried out with pyri-dines, quinolines, isoquinolines,acridine, pyridazines, pyrimidines, ethoxyquinolinium salts,and imidazoles. It also occurs with iV-oxides the mechanism of Scheme 13 has been suggested for pyridazine iV -oxide. ... 

Reaction conditions used for reduction of acridine [430,476, partly hydrogenated phenanthridine [477 and benzo f]quinoline [477 are shown in Schemes 38-40. Hydrogenation over platinum oxide in trifluoroacetic acid at 3.5 atm reduced only the carbocyclic rings in acridine and benzo[h]quinoline, leaving the pyridine rings intact [471]. 

Pyridine, quinoline and acridine show more positive oxidation potentials than the corresponding aromatic hydrocarbons. The oxidation potentials in Table 6.9 should be compared with data in Table 6.1. 

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