Premium
Synthesis of Luminescent Fused Imidazole Bicyclic Acetic Esters by a Multicomponent Palladium Iodide‐Catalyzed Oxidative Alkoxycarbonylation Approach
Author(s) -
Veltri Lucia,
Prestia Tommaso,
Russo Patrizio,
Clementi Catia,
Vitale Paola,
Ortica Fausto,
Gabriele Bartolo
Publication year - 2021
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202001693
Subject(s) - bicyclic molecule , chemistry , catalysis , isomerization , imidazole , iodide , amine gas treating , palladium , methyl iodide , medicinal chemistry , organic chemistry , combinatorial chemistry
A new multicomponent catalytic approach to important fused imidazole bicyclic acetic esters, whose core is present in many biologically active principles, is presented. It is based on the sequential cyclization‐alkoxycarbonylation‐isomerization of readily available N ‐heterocyclic propargylamine derivatives, carried out under oxidative conditions using a simple catalytic system consisting of PdI 2 (1 mol%) in conjunction with KI (1 equiv.), in the presence of AcONa as additive (1 equiv.) at 100 °C under 20 bar of a 4 : 1 mixture CO‐air. Under the optimized conditions, several N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amines were smoothly converted into alkyl 2‐(imidazo[1,2‐ a ]pyridin‐3‐yl)acetates in fair yields (51–77 %). The method was also applied to the conversion of N ‐(prop‐2‐yn‐1‐yl)pyrimidin‐2‐amine into 2‐(imidazo[1,2‐ a ]pyrimidin‐3‐yl)acetate and of N ‐(prop‐2‐yn‐1‐yl)pyrazin‐2‐amine into 2‐(imidazo[1,2‐ a ]pyrazin‐3‐yl)acetate. Some of the newly synthesized bicyclic derivatives have shown promising luminescence properties.