N-methylacridinium

The acridanyl radical is also obtained from N-methylacridinium chloride 83 and potassium cyanide in air-saturated DMF, DMSO, or DMSO/water mixtures. It is a remarkably stable radical 137> when 83 is treated with excess cyanide and oxygen N-methylacridone and cyanate are produced with light emission ... 

The reaction of 9-carboxy-N-methylacridinium chloride 88 with potassium persulfate in aqueous base is chemiluminescent, the quantum yields approaching 0.02 at high base concentrations. N-methylacridone is the emitter 141>. 

Abbreviations SPQ 6-methoxy-N -(sulfopropyl)quinolinium SPA N-(sulfopropyl)acridinium lucigenin bis-N-methylacridinium nitrate MACA 10-methylacridinium-9-carboxamide MAMC N-methylacridinium-9-methyl carboxylate. 

Photoinduced oxidation of Cjq has been achieved by electron transfer from excited to a strong electron acceptor such as p-chloranil [72, 73], p-benzoquinone [73], tetracyano-p-quinodimethane (TCNQ) or tetracyanoethylene (TONE). This electron transfer proceeds efficiently only by addition of promoters such as Sc(OTf)3 or triflic acid, both of which strongly enhance the electron-transfer process [72, 73]. Another possibility to produce the cation is the electron transfer from to the singlet excited state of a strong electron acceptor such as N-methylacridinium hexafluorophosphate (NMA ) [74, 75], triphenylpyriliumtetrafluoroborate (TPP" )... 

As a first example, the photochemical synthesis of substituted 1,2-dihydro-[60]fullerenes will be discussed. These compounds can be synthesized by various photochemical reaction pathways. In the first one the radical cation Qo is involved in the reaction. In 1995, Schuster et al. reported the formation of C6o radical cations by photosensitized electron transfer that were trapped by alcohols and hydrocarbons to yield alkoxy or alkyl substituted fullerene monoadducts as major products [211], Whereas Foote et al. used N-methylacridinium hexafluorophos-phate NMA+ as a sensitizer and biphenyl as a cosensitizer [167], Schuster et al. used 1,4-dicyanoanthracene (DCA) as a sensitizer for the generation of C 6o- The... 

Pyridine compounds in which phosphorus is directly attached to a ring carbon are relatively rare. Phosphorus nucleophiles are not able to replace ring hydrogen atoms in pyridines and pyridine 1-oxides. Some time ago it was found that pyridine yields a zwitterion (170) when it is heated under reflux in the presence of tetraphosphorus decasulfide (Scheme 105) (68MI20500). Recently, a product that contains a C—P bond was isolated after extended heating under the same conditions followed by treatment with hydrochloric acid (81JCR(S)285). However, it is uncertain whether free pyridine undergoes reaction in this case. Attack by phosphorus nucleophiles on salts is well established. N-Methylacridinium methosulfate affords a stable isolable 9,10-dihydro adduct (171) that readily forms a... 

Dibenzo-l,4-diazepines. l-Methyidibcnzo[6, -l,4-dia7epine (2) is obtained in 71.5% yield by reaclion of N-methylacridinium iodide (1) with hydroxylamine-O-sulfonic acid in absolute methanol containing 30% ammonia (3-4 hr., room tempera-... 

The reduction of N-methylacridinium is considerably more rapid than other nonenzymic transhydrogenation reactions. ... 

Methyl 30-acetoxy-A5-etienate, 118-119 Methyl N-acetylcysteinate, 425 N-Methylacridinium iodide, 256 Methyl acrylate, 107, 335 a-Methylalanine, 274 Methyl a-alkylaryl acetates, 494 a-Methylallyl acetate, 322 O-Methylandrocymbine, 499 O-Methylanhalonide, 250 N-Methylanilinomagnesium bromide, 11 N-Methylation, 197,450 S-Methylation, 85 2-Methylbenzofurane, 129 2-Methylbenzoquinone, 354, 355... 

It has not proved possible to classify these processes, but like reactions are grouped together. Carbon-oxygen bond homolysis is responsible for the formation of some of the products obtained on photodecomposition of liquid 1,3-dioxane, and the nucleophilic addition of primary alcohols to N-methylacridinium chloride to give... 

Two mechanistic studies relevant to photocuring processes have appeared. One deals with the efficient photoinduced generation of radical cations in solvents of medium and low polarity ". These cations act as sensitizers of the polymerization of N-methylacridinium hexafluorophosphate. The other is a study of the photochemistry of triarylsulphonium salts . 

Reductive alkylation of N-methylacridinium (87) occurs when it is irradiated with carboxylic acid salts. The reaction is thought to proceed by electron transfer from the carboxylate to the excited acrldinium ring followed by decarboxylation of RCOO coupling of the alkyl radical produced with the acridinyl radical then gives (88). A very similar sequence probably occurs in a reaction proposed as a synthetic procedure for decarboxylation of carboxylic acids.In this case an aza-aromatic compound such as acridine is irradiated with a carboxylic acid in benzene in the presence of tert-butyl thiol. The authors propose that a hydrogen bonded acridine-acid complex is excited and that adiabatic proton transfer is followed by electron transfer. This produces RCOO which decarboxylates, and reduction of the alkyl radical then ensues. The major fate of the acridine is coupling to (89) if the reaction is perfonned in the absence of oxygen. 

The formal hydride transfer between NAD analogues has been interpreted as a multistep but nonchain process involving electron and proton transfers (Ohno et al., 1981) or alternatively as a one-step hydride transfer with an appreciable primary isotope effect (Ostovic et al., 1983). Although not as yet recognized, a free radical chain mechanism should be possible in certain cases where [8] transfers an electron to an easily reducible NAD analogue such as N-methylacridinium ion. The chain could continue by hydrogen atom abstraction from [8] by the N-methylacridinyl radical. 

Example 4. The Reaction of i-Benzyl-i,4-dihydronicotinimide (BNAH) with N-methylacridinium Ion (AdA ) in Acetonitrile. Detailed studies of the reactions of BNAH and analogs with substituted isoquinoHnium cations were pubhshed by Bunting and co-workers in the early 1980s and later reviewed. ... 

N-Methylacridinium iodide allowed to stand 3-4 hrs. at room temp, with hydroxyl-amine-O-sulfonic acid in abs. methanol containing 30% NH3 -> 5-methyldibenzo-[b,e][l,4]diazepine. Y 71.5%. F. e. s. M. Hirobe and T. Ozawa, Tetrah. Let. 1971, 4493. 

Tetralkyl-silanes, -germanes, and -stannanes, as well as disilanes and distannanes, have been successfully used as alkyl radical precursors. The use of alkyl radicals is closely parallel to that presented above starting from ketals for the substitutive alkylation of aromatics and the conjugate addition to alkenes and alkynes (see Equations 4.5 and 4.28). Notice, however, that the final result depends on the sensitizer-trap used. Thus, N-methylacridinium perchlorate is reductively alkylated by hexamethyldisilane but undergoes reductive dimerization with the corresponding digermanes and distannanes. "... 

Following the conditions developed by Schuster et aL, Mattay et aL also generated using different sensitizers such as N-methylacridinium hexafluorophosphate (NMA+) and 2,4,6-triphenyl-pyrylium tet-rafluoroborate (TPP+) in the presence of biphenyL The assumed mechanism of formation of Cgo by this cosensitization is shown in Scheme 3. 

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