197524-37-1Relevant articles and documents
Efficient total synthesis of neocryptolepine and synthetic access to 6-methylquinindoline from a common intermediate
Méndez, María V.,Heredia, Daniel A.,Larghi, Enrique L.,Bracca, Andrea B. J.,Kaufman, Teodoro S.
, p. 28298 - 28307 (2017/07/07)
A convenient approach toward the indoloquinolines neocryptolepine and 6-methylquinindoline from a common intermediate, is reported. Both sequences, designed for maximum use of accessible reagents and robust conditions, are straightforward and efficient. They involved the amidation of 2-aminobenzaldehyde (prepared by iron-mediated reduction of 2-nitrobenzaldehyde) with 2-nitrophenylacetic acid, followed by a K2CO3-assisted cyclization to form a 3-(2-nitrophenyl)quinolin-2-one as the common precursor. Me2CO3-mediated N-methylation of the lactam, reduction of the nitro moiety and final cyclization resulted in 55% overall yield of neocryptolepine, whereas cyclocondensation and N-methylation afforded 79% overall yield of 6-methyl quinindoline. Thus, the sequences toward the targets entailed two POCl3-promoted C-N bond forming reactions, two Fe-mediated nitro group reductions and two base-promoted transformations.
A divergent approach to cryptotackieine and cryptosanguinolentine alkaloids
Fresneda, Pilar M.,Molina, Pedro,Delgado
, p. 7275 - 7278 (2007/10/03)
A seven-step synthesis of the 1-methyl-3-(o-azidophenyl)quinolin-2-one, a common intermediate for the synthesis of the cryptotackieine and cryptosanguinolentine alkaloids, is described. This intermediate is directly converted into cryptotackieine 1 by an intramolecular aza-Wittig reaction with trimethylphosphine; alternatively heating followed by reduction of the resulting indoloquinoline derivative provided cryptosanguinolentine 2.
