Synergetic copper/zinc catalysis: synthesis of aryl/heteroaryl-fused 1H-pyrrolo[3,2-c]pyridines

Abstract

The scaffolds having 1H-Pyrrolo[3,2-c]pyridine core show significant biological activity. Herein, we report a synergetic copper/zinc-catalyzed one-step annulation reaction of 2-amino (hetero)arylnitriles with ynamide-derived buta-1,3-diynes to deliver 1H-pyrrolo[3,2-c]quinoline-2,4-diamine derivatives in moderate...

Cu(ii)-catalyzed [4 + 1] and [4 + 3] annulation reactions: a modular approach to N-aryl/alkyl substituted 2,5-diamidopyrroles and diazepines

“…Very recently, photoisomerizable azobenzenes have been investigated as a ligand in the field of photopharmacology. 12 With our observation (entry 11, Table 1) and based on the literature findings, 8,9 a tentative route of this reaction was sketched (see the ESI, Scheme S1 †). We believe that Cu(OTf ) 2 which is likely formed in situ via anion exchange with Zn(OTf ) 2 might be an active catalyst in this reaction.…”

“…In line with our efforts in synthesizing small/medium ring aromatic heterocycles from ynamide-derived buta-1,3-diynes, 8 we planned to establish a single-step protocol for easy access to substituted pyrroles. Recently, we have developed a strategy to construct aryl/heteroaryl-fused 1 H -pyrrolo[3,2- c ]pyridines starting from ynamide-derived buta-1,3-diynes in one pot.…”

“…With our continuous interest in exploring copper-catalyzed novel transformation, 8 we herein report a general strategy for the synthesis of 2,5-diamido-substituted N -arylpyrroles from commercially available primary amines and ynamide-derived buta-1,3-diynes by a combination of copper( ii ) and zinc( ii ) salts (Scheme 1b). Furthermore, the feasibility of structurally unique diazepine synthesis from 2-aminothiazoles is also disclosed in this report.…”

Zinc‐Catalyzed [4+2] Annulation of 2‐Aminoarylnitriles with Ynamides: An Easy Access to Polysubstituted Quinolines

“…A plausible mechanism for the zinc-catalyzed [4 + 2] annulation of 2-aminoarylnitriles with ynamides is depicted in Scheme 6 on the basis of literature reports. [10,12,16] Initially, the nucleophilic attack of NH 2 moiety to the zinc-activated ynamide A/A' affords the vinylÀ zinc intermediate B, which after protodemetallation leads to enamine intermediate C. Then, an intramolecular cyclization via enamine attack to the zincactivated CN group takes place to give intermediate D. Finally, aromatization of D followed by protodemetallation generates the desired polysubstituted quinolines 3 and regenerates the zinc catalyst.…”

Synthesis and Reactivity of a Terminal 1-Alkynyl Triazene

“…The molecular structure of 15 was confirmed by single-crystal X-ray analysis (see the SI). Amide-functionalized 1,3-diynes are useful starting materials for the synthesis of substituted furanes, pyrroles, , thiophenes, and quinolines, and analogous transformations can be envisioned for 15 .…”