10-Methyl-9,10-dihydroacridine

Photoinduced electron transfer [22] from reductants such as l-benzyl-l,4-di-hydronicontinamide [27], the Hantzsch-ester [22] (diethyl-2,6-dimethyl-l,4-di-hydropyridine-3,5-dicarboxylate) or 10-methyl-9,10-dihydroacridine [27, 28] to the fullerene and successive proton transfer leads selectively to l,2-dihydro[60]fullerene. These reductions usually proceed under mild conditions. 

It has been demonstrated that visible light irradiation of the absorption band of AcrH + in the presence of organometallic compounds and alkenes and alkylbenzenes in MeCN results in efficient C-C bond formation between these electron donors and AcrH+ via photoinduced electron transfer from the donors to the singlet excited state of AcrH+ to yield the alkylated or allylated adducts selectively [89-91], The AcrH+ is also photoreduced by ethylbenzene and other alkylbenzenes to yield the corresponding 9-substituted-10-methyl-9,10-dihydroacridine [92] ... 

Fukuzumi S, Suenobu T, Kawamura S, Shida A, Mikami K (1997) Selective two-electron reduction of C60 by 10-methyl-9,10-dihydroacridine via photoinduced electron transfer. Chem Commun 291-292... 

Methyl- 10-hydroacridinyl radicals are involved in the electrochemical oxidation of 10-methyl-9,10-dihydroacridines with at least one of the 9-positions unsubstituted. If both 9-positions are substituted, 10-hydroacridinyl radicals are not involved since loss of a methylene proton from the initially formed 9,10-dihydroacridine cation-radical is impossible.261... 

The reduction of Ceo and Cvo has normally been achieved by the use of strong re-ductants such as BH3, which yield not only CeoHv and CV0H2 but also polyhydride mixtures [104, 230-237]. The use of the triplet excited state of Ceo has made it possible to attain the selective two-electron reduction of Ceo to l,2-CeoH2 by 10-methyl-9,10-dihydroacridine (AcrH2) which is a mild hydride donor (Eq. 14) [225, 238],... 

Bronsted acid catalysis in electron transfer described in Section 1.3.1 has also been effective for redox reactions via the electron transfer step. As shown in the case of metal ion-catalyzed hydride transfer reactions (see above), hydride transfer reactions from an NADH analogue to /7-benzoquinones also proceed via Bronsted acid-catalyzed electron transfer [255, 256]. Since NADH and ordinary NADH model compounds are subjected to the acid-catalyzed hydration [98, 257, 258], an acid-stable NADH model compound, 10-methyl-9,10-dihydroacridine (AcrH2), was used as a hydride donor to / -benzoquinone (Eq. 24) ... 

Hydride transfer reactions from NADH analogues to high-valent metal-oxo species provide excellent opportunity to clarify such a mechanistic difference by comparing the hydride transfer reactions with those with /)-benzoquinone derivatives, which have been discussed in the previous section. A series of NADH analogues, 10-methyl-9,10-dihydroacridine (AcrH2) and its 9-subsituted derivatives (AcrHR R =... 

A laser flash photolysis examination of the behaviour of fine particles of C o when irradiated in the presence of an electron donor has shown that photo-induced electron transfer occurs. The photoexcited triplet state of is reported to be capable of abstracting both an electron and energy from P-carotene, and the partitioning of the two routes is dependent on solvent polarity. Photoinduced electron transfer from NADH and its dimeric analogues to Cso yields Cgo However, if 10-methyl-9,10-dihydroacridine is used as... 

The same value was obtained by use of 10-methyl-9,10-dihydroacridine (AcrH2) as a kinetic probe. Independent kinetic determination yielded a rate constant = 9.4 x 10 s in 40% AN, Eq. (60). 

ABTS 2,2 -azinobis(3-ethylhenzothiazoline-6-sulfonate) ion AcrH2 10 -methyl-9,10 -dihydroacridine... 

For instance, UV and nuclear magnetic resonance (NMR) studies of the reaction between A-methylacridinium ion and primary aromatic amines have revealed the formation of unstable N-adducts under kinetically controlled conditions (—50°C). Their formation is especially favored in case of anilines bearing in the /jara-position an electron-donating substituent R. At temperatures above 0°C, these N-adducts are gradually converted into thermodynamically more favored C-adducts. Also it has been shown that when no oxidant is added, the A-methylacridinium cation acts as oxidant of both N- and C-adducts, thus giving the corresponding products and 10-methyl-9,10-dihydroacridine (Scheme 36) [11, 136]. 

Electron transfer processes, kinetics, and mechanisms for the oxidation of 10-methyl-9,10-dihydroacridine, as the model compound, and other 9-substituted l-methyl-9,10-dihydroacridines have been the subject of many studies [44, 207-211]. In particular, it has recently been found in our laboratory that nanocrystalline Ti02 with CdS nanoparticles embedded in its pores can accelerate the C-H functionalization of azaaromatic compounds. Indeed, the CdS/Ti02 composite proved to be an effective visible-light-driven photocatalyst for the oxidative step of the reaction of A -alkylacridinium salts with arylamines (Scheme 68). 

An enantioselective a-alkylation of aldehydes (R-CH2CHO) gives a xanthenyl product (137, X = O) in up to 93% ee, using a simple organocatalyst (138) that activates the aldehyde via enamine catalysis, with subsequent addition of the stabilized benzyllc carbocation. This dehydrogenative alkylation uses dioxygen as oxidant and has been extended to the cases of thioxanthene and 10-methyl-9,10-dihydroacridine (i.e. 137, X = S and NMe). 29... 

Scheme 8.67 MacMillan catalyst- and aerobic oxidation-promoted CDC reactions of xanthene, thioxanthene and 10-methyl-9,10-dihydroacridine with various aldehydes.

Methyl-9,10-dihydroacridine-9-carbonitrile in anhydrous ethanol gave the tribromide 153 which formed 2,7-dibromo-10-methyl-9(10fl)-acridone on recrystallization (2007MI1067 Scheme 60). 

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