89241-38-3Relevant articles and documents
A convenient access to 1,3-disubstituted furo[3,4-b]indoles by acid ion-exchange resin-catalyzed furan formation
Basset, Joan,Romero, Manel,Serra, Tha?s,Pujol, M. Dolors
, p. 356 - 362 (2012/01/06)
Efficient synthesis of furo[3,4-b]indoles starting from the corresponding indole is reported. The first route involves derivatization, protection, and deprotection steps, which stretch the syntheses. The second method provides a shorter and more efficient strategy to accessing the furoindole. The innovation starts with alkylation at C-2 of the indole presenting at the C-3 position a ketone-acetal, followed by the cycloaromatization catalyzed by polymeric ion-exchange resins. The second route represents a significant improvement over other methods previously described.
Synthesis and Diels-Alder Reactions of 1,3-Dimethyl-4-(phenylsulfonyl)-4H-furoindole. A new Annulation Strategy for the Construction of Ellipticine and Isoellipticine
Gribble, Gordon W.,Saulnier, Mark G.,Sibi, Mukund P.,Obaza-Nutaitis, Judy A.
, p. 4518 - 4523 (2007/10/02)
The novel fused heterocycle 1,3-dimethyl-4-(phenylsulfonyl)-4H-furoindole (4) is synthesized from 3-ethylindole (6) in six steps (46percent yield) or from indole-3-carboxaldehyde (12) in four steps (21percent yield).Furoindole 4 undergoes Diels-Alder reactions with dimethyl acetylenedicarboxylate, N-phenylmaleimide, benzyne, and 3,4-pyridyne (5) to give the expected adducts 17, 18a,b, 19, and 23a,b, respectively.Deoxygenation and desulfonylation of 19 and 23a,b, respectively, give benzocarbazole 22 and a readily separable mixture of the pyridocarbazole alkaloids ellipticine (1a) and isoellipticine (2a).
