Acridone alkylation

More recently Nishi et al.131 have reported the PTC procedure for the alkylation of acridone alkylation takes place exclusively at the nitrogen atom.186... 

Acridizinium salts, lO-(phenylsuIfonyl)-synthesis, 2, 545 5-Acridone UV spectrum, 2, 156 9-Acridone acylation, 2, 352 alkylation, 2, 350 synthesis, 2, 422 Acridone alkaloids, 2, 513 9-Acridonequinones synthesis, 2, 348 Acridones fluorescence, 2, 20 mass spectrometry, 2, 134 synthesis, 2, 93, 401 from 3-arylanthranils, 2, 496 from benzotriazinones, 2, 506 tautomerism, 2, 347 Acridones, tetrahydro-synthesis... 

Tlie interest in the preparation and use of dithiolium salts in connection with the synthesis of TTF derivatives led to the development of a new uses of heteroaromatic cations in organic synthesis. Based on that, a new carbonyl olefination for the synthesis of numerous heterofulvalenes was developed (77S861). For example, 2-dimethoxyphosphinyl-l,3-benzodithiole was deprotonated with butyllithium in THF at -78°C and the resulting phosphonate carbanion reacted with 9-alkyl-acridones to give the dithia-azafulvalenes of type 45 (78BCJ2674) (Scheme 15). 

Alkylation of 9-aminoacridine, under conditions analogous to those used for acridone, provides a convenient route to the 9-alkylaminoacridines [70], which are... 

The oxidation of AT-substituted 5//-dibenz[6,/] azepines with MCPBA is complex and depends upon the nature of the N-substituent. AT-Acyl derivatives do not form the N-oxide but suffer epoxidation of the 10,11-bond. AT-Aryl derivatives undergo hydroxylation of the phenyl ring, whereas N-alkyl congeners, with the exception of the AT-methyl compound, yield mixtures of diphenylamines and acridones. The N-oxide is obtained from the A/-methyl derivative along with ring-opened and ring-contracted products (81CPB1221). 

Willner and Halpern185 have described quantitative O-methylation of ac-ridone (119) under phase transfer conditions. But a more detailed study on alkylation of acridone under biphasic conditions by Galy et al.1 6 arrives at another conclusion the reaction gives a mixture of N- and O-alkylation products, with the N-alkyl derivative (120) predominating (65-100%). The yield of isolated N-alkyl derivative is 41-66%. 

Galy et al.190 studied the reaction of acridones with MeC=CBr. Only N-alkylation was observed. However, depending on the concentration of KOH, an isomerization occurred to give the N-allene. 

Alkyl substituents on the pyridone nitrogen atom are usually lost in reactions of this type, but the quaternary salts from /V-substituted acridones can be isolated. Pyrones (with PC15 or POCl3) form... 

The action of concentrated sulfuric acid at 0 °C on the geminal diazide 2 gives in high yield (> 90 %) the N-oxamoyl anthranilic acid 14 [72TH000], This compound can be further hydrolyzed to anthranilic acid 15 or converted into the ester 16. N-Alkyl derivatives of 2 behave in a similar manner cf. the conversion of 18 to 19. The latter compound may be easily degradated to 1,2,3,4-tetrahydroquinoline-l-carboxylic acid in the same way. Only the biphenyl derivative of 2 reacts differently and affords acridone 17 in 65 % yield. The cleavage of the C-3 - C-4 bond in these reactions is again noteworthy. 

Hydroxynoracronycine (40) is a constituent of Atalantia ceylonica and a metabolite of the antitumour compound acronycine its synthesis has been reported (Scheme 6).31 The reaction of l,3-dihydroxy-5-methoxy-9-acridone (36) with 3-chloro-3-methylbut-l-yne and cyclization in situ of the products furnished the chromenes (38) and (39) the formation of the intermediate (37) involves C-alkylation with the chlorobutyne, a reaction encountered previously during the synthesis of flindersine.32 Chromene (39) was converted into 11-hydroxy-noracronycine by successive methylation and demethylation. 

In principle, the photoreactions of CT s are able to offer a great number of photoinitiator systems for radical polymerization. But, so far, this subject has only received little attention, and the current knowledge relative to the photochemistry of such complexes is poor. In addition to the amine complexes mentioned above, chinoline-bromine [124-127], chinoline-chlorine [128], 2-methylpyridine-chlorine [129], pyridine-bromine [130], IV-vinylpyrrolidone-bromine [131], acridone-bro-mine [132], acridone-chlorine [133], benzophenone-S02 [134], isoquinoline-S02 [135, 136], and 2-methylquinoline-S02 [136] combinations are used for radical polymerization of AN, alkyl methacrylates, acrylic and methacrylic acid, and for... 

Acridone is aromatised to 9-methoxyacridine, m.p. 197°C, by dimethyl sulphate under phase transfer conditions (I. Willner and M. Halpern. Synthesis, 1979. 177). Substituted acridones give mainly ff-alkyacridones on treatment with simple alkyl halides under phase transfer conditions, but branched alkyl halides favour formation of the alkoayacridine (A. Mahamoud et al. J. heterocyclic Chem., 1982, 503). 

Tetraphosphorus decasulphide in hexamethylphosphoric triamide converts 9-acridones into the corresponding thiones, complementing the established routes from acridine and sulphur and from a 9-haloacridine and various sulphur reagents. The method is an improvement on the previous techniques for 0-S exchange in acridones (R.R. Smolders et al,. Synthesis, 1982, 493). Various thioacridones have beer. S-alkylated and S-acylated under mild phase transfer conditions, utilising the tautomeric nature of the thione (M. Vlassa, M. Kezdi and I. Goia, Synthesis, 1980, 850). 

The difference between the experimental and calculated dipole moments for a series of i7-alkyl derivatives of 9-acridone is attributed to a slight folding of the molecules. For lO-methyl-9-acridone, y is 5.20 D (A.-M. Galy et al., Farmaco Ed. Sci., 1981, 36, 38). 

Reisch et al. (93JHC981) described two different methods for the synthesis of 4-azaacronycine 71. One method involves the fusion of 1,3-dihydroxy-10-methyl-9(10//)-acridone 69 with 3-amino-3-methylbut-l-yne in the presence of CuCb in a closed ampule, followed by methylation (Scheme 13). The second method involves the A-alkylation of 3-amino-l-methoxy-lO-methyl-9(107/)-acridone 70 with 3-chloro-3-methylbut-l-yne, followed by in situ cyclization (Scheme 13). 

The reaction of Af-alkyl-5//-dibenz[6/]azepines with MCPBA <84CHEC-l(7)49i> has been extended to iV-benzyl-lO-substituted and 10,11-disubstituted derivatives <84CPB3857>. TTie products are 9-acyl-9//,10//-acridones, probably formed by acid-catalyzed rearrangement of the initially formed... 

Papadopoulos K, Lignos J, Stamatakis M, Dimotikali D, Nikokavouras J (1998) Radiochemiluminescence of acridones and alkyl acridities. J Photochem Photobio A Chem 115(2) 137-142. doi 10.1016/S1010-6030(98)00236-6... 

Alkaloids considered in this section derive biogenetically from 1,3-dihydroxy-lO-methylacridone (19) and 1,3-dihydroxyacridone (22) by simple deoxygenation and/or oxidation of the acridone aromatic skeleton. Subsequent O-alkylation very often takes place, and most natural acridones bear methoxy or methylenedioxy substituents. A few, exemplified by vebilocine (27) (94), evoprenine (28) (95), and 3-graanyloxy-l-hydroxy-4-methoxy-10-methylacridone (29) (96), are also substituted by prenyloxy or geranyloxy groups. 

Dihydroxyacridone prepared in this way has been used fiequently as a starting material for e synthesis of other acridone alkaloids including simple O-and JV-alkylated derivatives (288) and more complex C-prenylanidones (289), pyranoacridones (290,291), and acridone-coumarin mers (292). 

---