Facile Access to Benzothiazole‐Containing Pyrrolo[1,2‐a]quinolines and Pyrrolo[2,1‐a]isoquinolines via Nitrogen Ylides

Abstract

Quinoline and isoquinoline react with 2-(bromoacetyl)benzothiazole (1) in dry benzene to give the corresponding quinolinium and isoquinolinium salts 2 and 10 which undergo base-mediated [3+2] 1,3-dipolar cycloaddition with some acetylene and ethylene derivatives to give the corresponding benzothiazole-containing pyrrolo[1,2-a]quinoline and pyrrolo[2,1-a]isoquinoline derivatives.

Microwave‐Assisted Synthesis of Arylated Pyrrolo[2,1‐a]Isoquinoline Derivatives via Sequential [3 + 2] Cycloadditions and Suzuki‐Miyaura Cross‐Couplings in Aqueous Medium

“…In addition, the use of heteroaromatic N ‐ylides as 1,3‐dipoles is one of the most versatile synthetic tools for obtaining condensed heterocyclic structures via [3 + 2] cycloadditions . As part of our research work towards developing new routes for the synthesis of fused heterocyclic systems via N ‐ylides , as well as for microwave‐assisted synthesis of arylated heterocycles via C–C cross‐coupling reactions , we conduct here a novel route to some novel arylated pyrrolo[2,1‐ a ]isoquinoline derivatives via sequential [3 + 2] cycloadditions and Suzuki couplings starting from the isoquinolinium bromide 2 . The Suzuki–Miyaura cross‐coupling reactions will be carried out under thermal heating as well as microwave irradiation conditions using the benzothiazole‐oxime Pd(II)‐complex 5 as one of our reported most active precatalysts .…”

Synthesis of Pyrrolo[2,1-a]isoquinolines by Multicomponent 1,3-Dipolar Cycloaddition

“…One of the important and current methods for the synthesis of pyrrolo[2,1- a ]isoquinolines is the 1,3-dipolar cycloaddition reaction of isoquinolinium N -ylides with activated alkynes or olefins [20,21,22,23,24,25,26,27,28]. Our interest in studying convenient and simple methods for obtaining new pyrroloazine derivatives [29,30,31,32,33,34] led us to expand our studies to pyrrolo[2,1- a ]isoquinolines [27].…”