Preparation of new pyrido[3,4-b]thienopyrroles and pyrido[4,3-e]thienopyridazines

Metal‐Catalyzed Cross‐Coupling Reactions of Aminopyridines

“…Fiksdahl and Stockmann applied a Pd‐catalyzed Suzuki reaction of 3‐aminopyridine derivatives with suitable 2‐/3‐thiopheneboronic acids, to prepare biologically active pyrido[3,4‐ b ]thienopyrroles and pyrido[4,3‐ e ]thienopyridazines 87. The C–C coupling was performed with N ‐pivaloyl‐protected 3‐amino‐4‐bromopyridine in the presence of Pd(PPh 3 ) 4 /Na 2 CO 3 /toluene/ MeOH, 80–90 °C, which gave the desired thien‐2‐yl‐ or ‐3‐ylpyridine intermediates in 85 and 86 % yields, respectively.…”

Recent advances in application of intramolecular Suzuki cross-coupling in cyclization and heterocyclization

“…Several novel compounds of this type were prepared on the basis of a Suzuki coupling and subsequent cyclization approach by Stockmann and Fiksdahl [33]. Pyrido [4,3- b-Carboline analogues which are naturally occurring alkaloids were also prepared by Suzuki cross-coupling of the appropriate 2-and 3-thienylboronic acids and 4-bromo-3-pyridylpivaloylamide (78) (Scheme 19) and afforded the biaryl coupling products 82 and 83 in high yields (85 %), which were then elaborated into the target derivatives 90 and 91 [34].…”

Direct One-Pot Synthesis of Primary 4-Amino-2,3-diaryl-quinolines via Suzuki-Miyaura Cross-Coupling of 2-Aryl-4-azido-3-iodoquinolines with Arylboronic Acids

“…A literature search revealed two papers describing the outcome of tetrakis(triphenylphosphine)-palladium(0) [Pd(PPh 3 ) 4 ]-catalyzed Suzuki-Miyaura cross-couplings of 4-azido-3-bromopyridine with heteroarylboronic acids [ 19 ] and 1-azido-2-bromobenzene with a series of aryl- and heteroarylboronic acids [ 20 ]. In one case, involving the coupling of 1-azido-2-bromobenzene with 2-thiopheneboronic acid, the authors isolated 2-(2-azidophenyl)thiophene (40%), bromoaniline (2%) and 2-thiophenylaniline (3%) as products [ 20 ].…”