3-Methylcarbazole studies

In contrast to the 1- and 2-oxygenated tricyclic carbazole alkaloids, most of the 3-oxygenated and the 3,4-dioxygenated tricyclic carbazole alkaloids were isolated from Streptomyces (Scheme 2). Their common structural feature is a 2-methylcarbazole, although biosynthetic studies on carbazomycin B have shown that tryptophan is the precursor of the carbazole nucleus [26]. 4-De-... 

Chakrabortys biomimetic hydroxylation studies of 3-methylcarbazole (2) using Udenfiiend conditions (Fe /EDTA/ascorbic acid/oxygen) furnished a bis-carbazole, as a result of biomimetic dimerization of 3-methylcarbazole. This reaction, which is a prototype of hydroxylation followed by dimerization, provides circumstantial evidence for the existence of bis-carbazole alkaloids in higher plants (369,371). 

The effect of oxygen on the photocyclization of A-methyldiphenylamine to N-methylcarbazole in n-hexane, water, and aqueous surfactants has been studied by... 

Hoffmann, D., G. Rathkamp, and Y. Liu Chemical studies on tobacco smoke. XXVI. On the isolation of volatile and nonvolatile A-nitrosamines and hydrazines in cigarette smoke in A-Nitrosamines in the environment, edited by P. Bogovski and E.A. Walker, lARC, Lyon, Prance, lARC Sci. Publ. No. 9 (1974) 159-165. Hoffmann, D.,G. Rathkamp, and S. Nesnow Quantitative determination of 9-methylcarbazoles in cigarette smoke Anal. Chem. 41 (1969) 1256-1259. 

Further studies of the photochemically induced conversion of JV-methyl-diphenylamine into N-methylcarbazole have been reported.28 Two successive intermediates have been detected, namely the amine triplet and iV-methyl-4a,4b-dihydrocarbazole. Oxygen appears to participate in the overall reaction in two ways, viz. by dehydrogenation of the dihydrocarbazole intermediate to carbazole and by quenching the amine triplet. Non-oxidative cyclization of 5-(iV-methyl-anilino)- and 5-(iV-acetylanilino)-l,3-dimethyluracil (26) similarly gives the trans-dihydropyrimido[5,4-6]indoles (27) in high yield.24 Orbital symmetry arguments... 

Cytochrome P-450 Catalyzed Reactions - Studies with 02 have established that the cytochrome P-450 mediated hydroxylation of camphor by the bacterial enzyme and the enzyme purified from rat liver results in the incorporation of atmospheric oxygen in the 5-exo-hydroxylation product. Cumene [ 02]hydroperoxide will transfer its peripheral oxygen atom to a variety of compounds which serve as substrates for mammalian cytochrome P-450. As expected, 02 served as the oxygen source for the bacterial cytochrome P-450 catalyzed epoxidation of 5,6-dehydrocamphor.N-Hydroxy-methylcarbazole, formed by the cytochrome P-450 catalyzed oxidation of N-raethylcarbazole, incorporates 0 exclusively from dioxygen. Under anaerobic conditions cytochrome P-450 may catalyze the intramolecular transfer of oxygen present in tertiary amine N-oxides. Mechanistic studies on S-dealkylation and S-oxidation reactions also have used tracer methods. ... 

The mechanism of cyclisation of 2-nitreno-biphenyls has been studied. The decomposition of 2-methyl-T-nitrenobiphenyl under singlet-promoting conditions gives 4-methylcarbazole (263), while the phenanthridine (264) is the major product under triplet-promoting conditions. 

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