40619-73-6Relevant academic research and scientific papers
Ynesulfonamide-Based Silica Gel and Alumina-Mediated Diastereoselective Cascade Cyclizations to Spiro[indoline-3,3′-pyrrolidin]-2-ones under Neat Conditions
Wang, Yanshi,Wang, Xiaoyu,Lin, Jingsheng,Yao, Bo,Wang, Guanghui,Zhao, Yuandong,Zhang, Xinhang,Lin, Bin,Liu, Yang,Cheng, Maosheng,Liu, Yongxiang
, p. 1483 - 1492 (2018)
The spiro[indoline-3,3′-pyrrolidin]-2-ones were synthesized via a silica gel and alumina-mediated sequential transformation based on tryptamine-derived ynesulfonamide substrates under neat conditions. The inherent tendency of C?C bond migration through Wagner-Meerwein rearrangement in the synthesis of spirooxindole was prevented by water trapping to the spiroindoleninium intermediate. The functional group tolerances of the methodology were investigated using a variety of substrates. The detailed mechanism of the sequential transformation was probed by the isotope-labeled experiments. This strategy was further applied in the formal syntheses of indole alkaloids coerulescine and horsfiline. (Figure presented.).
Br?nsted Acid-Catalyzed Tandem Cyclizations of Tryptamine-Ynamides Yielding 1H-Pyrrolo[2,3-d]carbazole Derivatives
Wang, Yanshi,Lin, Jingsheng,Wang, Xiaoyu,Wang, Guanghui,Zhang, Xinhang,Yao, Bo,Zhao, Yuandong,Yu, Pengfei,Lin, Bin,Liu, Yongxiang,Cheng, Maosheng
supporting information, p. 4026 - 4032 (2018/01/15)
Ynamides, as versatile synthetic precursors, have attracted much attention from synthetic chemists and sparked the development of a number of methodologies for the construction of various structures. 1H-Pyrrolo[2,3-d]carbazole is a core scaffold of a series of monoterpene indole alkaloids found in Kopsia, Strychnos, and Aspidosperma, for example. In this study, 1H-pyrrolo[2,3-d]carbazole derivatives were synthesized by a Br?nsted acid-catalyzed tandem cyclization starting from tryptamine-based ynamides. This strategy prevented Wagner–Meerwein rearrangement by instantaneous intramolecular nucleophilic trapping of the indoleninium to afford a tetracyclic indoline via an in situ-formed enol species induced by the formation of a more stable conjugate diene moiety. The functional group tolerances were investigated by using a series of readily available substrates. A plausible mechanism has been proposed based on the evidence of the capture of the hemiaminal intermediate. Lastly, a Büchi ketone, which is the pivotal intermediate in the synthesis of the indole alkaloid vindorosine, was synthesized by utilizing our newly developed methodology.
Synthetic approaches to highly functional -carboline building blocks via allylic amidation
Teichert, Johannes F.,Fananas-Mastral, Martin,Feringa, Ben L.
experimental part, p. 409 - 416 (2012/03/11)
A new, straightforward synthesis of highly functional -carboline building blocks is presented that makes use of allylic amidation methodology. The products obtained carry a terminal double bond as well as an easy-to-deprotect amide, which make them perfectly suitable for further functionalization. The use of the trifluoroacetamide group is exploited in a dual fashion; it acts as a protecting group and functions as the nucleophile for the allylic amidation reaction. Georg Thieme Verlag Stuttgart New York.
Aromatization of 1,6,7,7a-tetrahydro-2H-indol-2-ones by a novel process. Preparation of key-intermediate methyl 1-benzyl-5-methoxy-1H-indole-3-acetate and the syntheses of serotonin, melatonin, and bufotenin
Revial, Gilbert,Jabin, Ivan,Lim, Sethy,Pfau, Michel
, p. 2252 - 2256 (2007/10/03)
Imine 7 of 1,4-cyclohexanedione mono-ethylene ketal 6 was reacted with maleic anhydride, affording the cyclized adduct 8. Methyl esterification of 8, accompanied by transacetalization, led to the dihydrooxindole derivative 10. Aromatization of 10 was then accomplished with POCl3, leading directly to the key-intermediate title compound 11 in 74% yield from ketone 6. Serotonin, melatonin, and bufotenin were then obtained by standard reactions.
