89241-37-2Relevant academic research and scientific papers
An efficient synthesis of 4-(phenylsulfonyl)-4H-furo[3,4-b]indoles
Gribble, Gordon W.,Jiang, Jun,Liu, Yanbing
, p. 1001 - 1003 (2007/10/03)
The fused heterocycle 4-(phenylsulfonyl)-4H-furo-[3,4-b]indole, which is an indole-2,3-quinodimethane synthetic analogue, is prepared in five steps from indole in 46% yield. A similar sequence is used to synthesize C-3 derivatives (3-methyl, 3-phenyl, and 3-heptyl). Thus, indole-3-carbaldehyde (1) is protected as the N-phenylsulfonyl derivative 2 and converted to the ethylene acetal 6. Lithiation at C-2 followed by treatment with an aldehyde affords the expected hydroxy acetals 7 and 8. Exposure to acid effects cyclization to the furoindoles 5 and 9. Furthermore, C-1 lithiation of furo[3,4-b]indole 9c followed by treatment with methyl iodide affords disubstituted furo[3,4-b]indole 10.
4-(PHENYLSULFONYL)-4H-FUROINDOLE - A STABLE SYNTHETIC ANALOGUE OF INDOLE-2,3-QUINODIMETHANE
Saulnier, Mark G.,Gribble, Gordon W.
, p. 5435 - 5438 (2007/10/02)
The N-phenylsulfonyl derivate (2) of the previously unknown fused heterocycle 4H-furo indole is synthesized from indole-3-carboxaldehyde (3) in 28percent yield and undergoes a Diels-Alder reaction with benzyne to give 5H-benzocarbazole (11) in 33percent yield after deoxygenation and deprotection.
