Synthesis of tetrahydroisoquinolines through TiCl4-mediated cyclization and Et3SiH reduction
作者:Zeyu Shi、Qiong Xiao、Dali Yin
DOI:10.1016/j.cclet.2019.09.023
日期:2020.3
Abstract A versatile and efficient telescoped reaction sequence for the synthesis of tetrahydroisoquinolines (THIQs) is reported that uses TiCl4 to promote cyclization of a benzylaminoacetal derivative and Et3SiH for reduction of the intermediate 4-hydroxy-THIQ. This method is complimentary to the classical Pomeranz-Fritsch and related reactions since it tolerates electron-withdrawing substituents
Preparation of Polycyclic Azaarenes by an Extended Pomeranz-Fritsch Procedure
作者:Michael Hewlins、Rhys Salter
DOI:10.1055/s-2007-983744
日期:——
An extension of the Pomeranz-Fritsch procedure has been evaluated as a route to some polycyclic azaarenes. Aromatic aldehydes were treated with the dimethyl and diethyl acetals of 2-aminoethanal, the resulting imines reduced to amines which were tosylated and the resulting sulfonamides treated under a range of acidic conditions. The two naphthaldehydes led to benzo[f]isoquinoline and benzo[h]isoquinoline in overall yields of 13% and 36%. Phenanthrene-9-carbaldehyde and phenanthrene-3-carbaldehyde gave dibenzo[f,h]isoquinoline and naphtho[2,1-g]isoquinoline, respectively, as the major tetracyclic products. No pentacyclic product was obtained from a similar sequence starting from pyrene-1-carbaldehyde.
Ultrasound assisted one-pot synthesis of benzo-fused indole-4,9-dinones from 1,4-naphthoquinone and α-aminoacetals
作者:Quang H. Luu、Jorge D. Guerra、Cecilio M. Castañeda、Manuel A. Martinez、Jong Saunders、Benjamin A. Garcia、Brenda V. Gonzales、Anushritha R. Aidunuthula、Shizue Mito
DOI:10.1016/j.tetlet.2016.04.031
日期:2016.5
A one-pot synthesis of benzo[f]indole-4,9-diones from 1,4-naphthoquinone with alpha-aminoacetals has been developed. This method provides a straightforward synthesis of benzo[f]indole-4,9-diones via intramolecular nucleophilic attack of aminoquinones to aldehydes under mild reaction conditions. The detailed mechanism was also investigated. (C) 2016 Elsevier Ltd. All rights reserved.