N-methylacridone

Similarly the N-methylacridone derivative 59 yielded chemiluminescence which was about a third that of 58. In this case the donor part of the molecule, i.e. the phthalic hydrazide, cannot produce a fluorescent product at all, but on its oxidation excited phthalate dianions very probably are produced 124>. From a series of other compounds of this type (60, 61, 62)... 

Lucigenin 71 chemiluminescence is more complicated than that of luminol and related compounds due to the presence in the reaction mixture of several species capable of emission 135>. N-Methylacridone 72, however, has been established as the primary excited product (for references see 0 p. 90) from which energy transfer occurs to the other species 3>. 

In view of the increasing interest in the radical ion chemiluminescence 71 has also been investigated to see whether radical ions play an essential role here, especially by E. G. Janzen et al. 136,137,138) The reaction pathway to N-methylacridone 72 was thought to proceed perhaps via a homolytic cleavage of the lucigenin carbinol base 74, yielding N-methylacridone radical anion 75. 

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 radical 85 yields the peroxide anion 86 the decomposition of which gives rise to excited N-methylacridone and cyanate. In addition to previous suggestions put forward in respect of this exergonic decomposition 3.139) (see also p. 97), a recombination of the radical 85 and the peroxy radical 87 (from 86 and O2) according to... 

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>. 

A homolytic cleavage of the peroxy bond in 90 to yield the radical anion 90 a with subsequent elimination of CO 2 and formation of the N-methylacridone radical anion (see p. Ill) should be a possible pathway, too, but as radical scavengers enhance the 88 chemiluminescence 141> it appears rather improbable. 

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. 

A further study of the root alkaloids of Ruta graveolens has resulted in the identification of a new chlorine-containing acridone (31), named iso-gravacridonchlorine.29 The same source yielded an inseparable mixture of alkaloids, shown by n.m.r. spectroscopy to consist of the new compound furacridone (32) and the known compound l-hydroxy-3-methoxy-N-methylacridone (29 R = H) in a ratio of 4 1. 

Synthesized 1,3-dihydroxy-N-methylacridone is readily incorporated into rutacridone by cell-free extracts of Ruta graveolens (Maier et al, 1993). It has been hypothesized that the final step in the biosynthesis of these alkaloids... 

Baumert, A., Porzel, A., Schmidt, J. and Groger, D. (1992) Formation of 1,3-dihydroxy-N-methylacridone from N-methylanthranoyl-GoA and malonyl-CoA by cell cultures of Ruta graveolens. Z. Naturforsch., 47c, 365-8. 

Maier, W., Baumert, A., Schumarm, B., Furukawa, H. and Groger, D. (1993) Synthesis of 1,3-dihydroxy-N-methylacridone and its conversion to rutacridone by cell-free extracts of Ruta graveolens cell cultures. Phytochemistry, 32, 691-8. 

Photophysics of Acridone, N-Methylacridone, Acridine, and Pyrene Adsorbed on Silica Gel (Satoshi Suzuki and Tsuneo Fujii)... 

The fluorescence spectra of N-methylacridone adsorbed on SG200A are given in Fig. 5. The fluorescence band of adsorbed N-methylacridone is located at the wavenumber between the bands in ethanol and in O.IN sulfuric acid and the situation is identical to the case of acridone. This suggests that the hydrogen bond is... 

Structure (85) for a new alkaloid of Atalantia monophylla was based on the n.m.r. spectrum.An alkaloid obtained from Boenninghausenia albiflora, formerly regarded as 1,7-dihydroxy-N-methylacridone, has now been shown from the n.m.r. spectrum to... 

Table 3J1. Wavelength and Energy Shift in N-Methylacridone-Lewis Acid Complexes...

Seitdem die Bildung der Acridinbasen (z.B. 1,2,3-Trimethoxy-N-methylacridon (CCLXVI) aus Evodia alata) unter. .zellmoglichen" Be-dingungen (s. Schema 48) gelungen ist (146), muB man annehmen, daB dieser Alkaloidtyp auch in der Pflanze aus Anthranilsaure entsprechend Schema 48 aufgebaut werden kann. 

A preliminary study of the acridone alkaloids of the roots of Boenninghausenia albiflora resulted in the identification of 1-hydroxy-N-methylacridone (41 R = Me) now the Ruta alkaloid rutacridone (42) (c/. Vol. 8, p. 84) and noracrony-cine (43) have been isolated from this species. Of two new alkaloids obtained from B. albiflora, one was shown to be 1-hydroxyacridone (41 R = H) by methylation to (41 R = Me). The n.m.r. spectrum of the other new alkaloid suggested that it was a dihydroxy-N-methyl-acridone in which ring B contained a 1-hydroxy-group and three adjacent aromatic hydrogen atoms structure (44) was proposed. 

---