Synthesis of Novel 5,6‐Dihydropyrrolo[2,1‐a]isoquinolines via Grob Reaction between (E)‐1,1,1‐Trifluoro‐3‐nitro‐2‐butene and 3,4‐Dihydroisoquinolines

Abstract

Uncatalyzed cycloaddition of 3,4‐dihydroisoquinolines to (E)‐1,1,1‐trifluoro‐3‐nitro‐2‐butene via Grob reaction provide a simple one‐step route to the 5,6‐dihydropyrrolo[2,1‐a]isoquinolines, which represent the basic structural framework of the antitumor active alkaloid crispine.

Base-Promoted Intermolecular Cyclization of Substituted 3-Aryl(Heteroaryl)-3-chloroacrylaldehydes and Tetrahydroisoquinolines: An Approach to Access Pyrrolo[2,1-a]isoquinolines

“…Sequential elegant studies (Scheme ) using metal catalysis (e.g., Ir, Ru, Rh, Ag, Cu, etc.) were accomplished by several research groups. − …”

Synthesis of 3‐Aminopyrido[2,1‐a]isoquinolin‐4‐one Derivatives via Condensation of Azlactones with 1‐Alkyl‐3,4‐dihydroisoquinolines

“…1‐Alkyl‐3,4‐dihydroisoquinolines can exist in two tautomeric forms, [21a–f] imine and enamine. They react with 4‐benzylideneoxazol‐5(4 H )‐one as enamines to form 3‐amino‐2,3,6,7‐tetrahydro‐4 H ‐pyrido[2,1‐ a ]isoquinolin‐4‐one amides [19,20g] which can be oxidized to 3‐aminopyrido[2,1‐ a ]isoquinolin‐4‐one derivatives in low and moderate yield [19] …”

Synthesis of Novel 13a‐(ω‐Aminoalkyl)‐8‐oxoberbines by Means of Reaction of Homophthalic Anhydride with 1‐Substituted 3,4‐Dihydroisoquinolines. An Unexpected Formation of a Pyrrolo[3,4‐i]berbindione

“…Compounds 8 and 9 can be regarded as β,β′‐, respectively, β,γ′—diamino acid derivatives, and as such, they are expected to possess biological activity or they could serve as starting materials for further functional groups transformations of the protoberberines. From the other hand, the versatility of 1‐substituted 3,4‐dihydroisoquinolines as synthons for the preparation of fused polyheterocyclics containing bridgehead nitrogen atom is demonstrated by this research once more.…”