158991-81-2Relevant academic research and scientific papers
Unusual Formation of Cyclopenta[ b]indoles from 3-Indolylmethanols and Alkynes
Gandhi, Soniya,Baire, Beeraiah
, p. 3904 - 3918 (2019)
Acid-promoted synthesis of cyclopenta[b]indole frameworks from 3-indolylmethanols and alkynes has been reported. The overall transformation represents a formal [3 + 2] annulation via rearrangement. This protocol showed good generality for the carbinol substrates as well as alkynes and allowed the generation of structurally diverse cyclopenta[b]indoles. Terminal alkynes, dialkyl-substituted internal alkynes, and alkynes with electron-deficient substituents were found to be not suitable for this transformation. Similarly, N-Ts and N-Boc groups were compatible with reaction conditions, whereas N-Ac and N-Tf failed to undergo this reaction. Isolation of vinyl chloride intermediate suggested the involvement of a vinylic carbocation intermediate. A mechanism has been proposed involving a ring-opening-ring-closing cascade followed by a 1,3-indole migration process via a spirocyclobutene intermediate.
Organocatalytic asymmetric Michael addition of aliphatic aldehydes to indolylnitroalkenes: Access to contiguous stereogenic tryptamine precursors
Chen, Jian,Geng, Zhi-Cong,Li, Ning,Huang, Xiao-Fei,Pan, Feng-Feng,Wang, Xing-Wang
, p. 2362 - 2372 (2013/05/21)
Because of the importance of the indole framework and the versatile transformation of nitro and formyl groups, the efficient synthesis of optically pure 2-alkyl-3-(1H-indol-3-yl)-4-nitrobutanals, one type of tryptamine precursors are of great interest for pharmaceutical and biological research. Herein, the Michael addition of aliphatic aldehydes to indolylnitroalkenes has been developed using (S)-diphenylprolinol trimethylsilyl ether as an organocatalyst, which provides the desired optically pure syn 2-alkyl-3-(1H-indol-3-yl)-4-nitrobutanal derivatives in up to 98% yield with up to >99:1 dr and >99% ee. To show the synthetic usefulness of this methodology, optically active 2-alkyl-4-nitro-3-(1-tosyl-1H-indol-3-yl)butan-1- ol and tryptamine derivatives are readily obtained by stepwise systematic transformations.
Enantioselective synthesis for the (-)-antipode of the pyrazinone marine alkaloid, hamacanthin A
Jiang,Yang,Wang
, p. 4865 - 4869 (2007/10/03)
A short enantioselective total synthesis for the (-)-antipode of the antifungal marine alkaloid, hamacanthin A, (6R)-3,6-bis(6-bromoindol-3-yl)-5,6-dihydro-2(1H)-pyrazinone, is described. This synthesis proceeds through the coupling of 3-indolyl-αoxoacetyl chloride and 3-indolyl azidoethylamine, followed by intramolecular aza-Wittig type cyclization. A concise and useful approach for the synthesis of (1R)-1-(indol-3-yl)-2-azidoethylamine using the Sharpless asymmetric dihydroxylation reaction followed by stereospecific azidation is also presented.
A new synthesis of 5-bromoaplysinopsin, 6-bromoaplysinopsin and 3'-demethylaplysinopsin and their biological activities
Gulati, Deepa,Chauhan, P. M. S.,Pratap, Ram,Bhakuni, D. S.
, p. 10 - 16 (2007/10/02)
A new synthesis of 5-bromoaplysinopsin (11), 6-bromoaplysinopsin (15) and 3'-demethylaplysinopsin (24) has been developed.A number of their analogues have been synthesized and evaluated for biological activities.Of the compounds tested, compounds 5, 7-9 a
