Formamidines in synthesis. An efficient one-pot synthesis of 7-substituted indolines via intramolecular cyclization of (2-phenethyl)formamidines. An asymmetric route to benzopyrrocoline alkaloids
作者:Thais M. Sielecki、A. I. Meyers
DOI:10.1021/jo00039a029
日期:1992.6
o-Chloro-beta-phenethylamines, transformed into the N-tert-butylformamidines, were found to be excellent precursors to indolines following benzyne formation. A series of methoxy-substituted o-chlorophenethylamines containing an N-alkyl or aryl substitutent were subjected to sec-butyllithium producing the ortho-lithiated aromatic which subsequently lost lithium chloride at temperatures ranging from -78 to -50-degrees-C. The resulting benzyne was intramolecularly trapped providing the titled heterocycles. Quenching the reaction resulted in elimination of the tert-butyl isocyanide (isolated after aqueous workup as tert-butylformamide) and protonation (or alkylation) of the 7-lithio position. Overall the yields for this process were 60-95% for a variety of N-substituted phenethylamines. In addition, a one-pot total asymmetric route to benzopyrrocoline alkaloids was featured using this benzyne trapping of chiral formamidines.
[DE] PYRROLOPYRIDIN-DERIVATE UND DEREN VERWENDUNG ZUR NUKLEARMEDIZINISCHEN BILDGEBUNG<br/>[EN] PYRROLOPYRIDINE DERIVATIVES AND THEIR USE FOR NUCLEAR-MEDICAL IMAGING<br/>[FR] DÉRIVÉS DE PYRROLOPYRIDINE ET LEUR UTILISATION POUR L'IMAGERIE MÉDICALE NUCLÉAIRE
申请人:HELMHOLTZ ZENTRUM DRESDEN
公开号:WO2020108688A1
公开(公告)日:2020-06-04
Die Erfindung betrifft eine Verbindung der allgemeinen Formel (I), worin Ar ein Pyridin-Ring ist. Außerdem ist eine Präkursor-Verbindung zur Herstellung einer Verbindung der Formel (I) vorgesehen, die anstelle einer Gruppe R1 eine Abgangsgruppe aufweist.