Solvent-free synthesis of δ-carbolines/carbazoles from 3-nitro-2-phenylpyridines/2-nitrobiphenyl derivatives using DPPE as a reducing agent
A green and efficient preparation of functionalized δ-carbolines/ carbazoles via reductive ring closure by 1,2-bis(dipenylphosphino)ethane under solvent-free conditions is described. The starting materials 3-nitro-2-phenylpyridines/2-nitrobiphenyl derivatives are readily prepared through Suzuki-Miyaura cross-coupling reaction from commercially available compounds. And the polar by-product ethane-1,2-diylbis(diphenylphosphine oxide) is easily removed from the relatively polar reaction mixture. Various substituted δ-carbolines/carbazoles are obtained in acceptable yields. It is particularly worth mentioning that substrates with electron-withdrawing groups (EWG) also give the desired products in good yield.
Microbial transformation of selected carbazole derivatives
A strain of Pseudomonas aeruginosa and another of Aspergillus fumigatus are found to have the ability to degrade carbazole derivatives. These strains show different specificities for growth on 1- and 3-methylcarbazoles and accumulate forraylcarbazoles as end products in low yields. Pseudomonas species degrade 1- and 3-formylcarbazoles to the corresponding carboxylic acid derivatives which in turn are decarboxylated to carbazole in high yields. This strain also biotransforms the N-acetylcarbazoles (8, 9 and 10) and the respective deacetyl-derivatives (7,2 and 11) are obtained in good yields. This study provides an evidence in favour of the suggested biotransfonnation of 3-methylcarbazole to carbazole via 3-formylcarbazole and carbazole-3-carboxylic acid in the plants.
Chakraborty,Chowdhury
p. 617 - 620
(2007/10/03)
Photochemical formylation of selected methyl and dimethyl carbazoles
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Chowdhury,Saha,Poddar
p. 63 - 65
(2007/10/02)
Photochemical formylation of carbazole and diphenylamine
Carbazole (1) and diphenylamine (7) undergo photo-chemical formylation in chloroform solution to furnish the corresponding formyl derivatives 2, 3 and 8, 9 respectively. The reaction has been successfully extended to 1-methylcarbazole (4) to yield formyl derivatives 5 and 6.
Chowdhury,Saha,Podder
p. 405 - 406
(2007/10/02)
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