An efficient tandem process for the selective synthesis of 1,2‐annulated α‐fused quinoxalines using benzotriazole methodology by a modified Pictet–Spengler reaction is described. The approach involves the reaction of arylamines 4 with aromatic aldehydes 5 to furnish 6‐endo‐dig‐cyclized products. Dihydroquinoxalines 6 were selectively obtained by using AlCl3 in tetrahydrofuran (THF) at room temperature for two hours. However, after ten hours, quinoxalines 7 were obtained exclusively in excellent yields. A series of biologically important fluoro‐ and piperazenyl‐substituted quinoxalines were also synthesized. This developed methodology also provides access to a novel tandem synthesis of quinoxalinones 9.

Oral cancer patients have a potentially difficult airway but, if managed properly during perioperative period, morbidity and mortality can be reduced or avoided. Oral cancer patients can be managed safely without the routine use of a tracheostomy. Nasotracheal intubation is a safe alternative to tracheostomy in oral cancer patients except in some selected patients.

An efficient approach for the copper-catalyzed regioselective tandem synthesis of diversely substituted indolo[2,1-a]isoquinolines 11a-r, pyrrolo[2,1-a]isoquinolines 12a-d, and indolo-, pyrrolo[2,1-f][1,6]naphthyridines 14a-f via preferential addition of the heterocyclic amines onto the ortho-haloarylalkynes over N-arylation followed by intramolecular C-2 arylation is described. The scope of the developed chemistry was successfully extended for the direct synthesis of bisindolo-, pyrrolo[2,1-a]isoquinolines 15a-g, a regioisomer of the bisindolo[1,2-a]quinolines used as organic single-crystal field-effect transistor. Hydroxymethyl benzotriazole, which is an inexpensive and air stable compound, has been used as a ligand to carry out this one-step conversion of simple, readily available starting materials into an interesting class of heterocyclic compounds.

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An efficient approach for the synthesis of pyrrolo[3,2-c]quinolines (the core nucleus of the natural product martinellic acid) from protected 2-alkynylanilines via the regioselective formation of pyrroles followed by Heck and intramolecular Michael addition has been described.

A new class of bidentate ligand, 1-(pyridine-2-yl)-1H-benzo [d]A C H T U N G T R E N N U N G [1,2,3]triazole has been designed and employed for the palladium-catalyzed C À C (Suzuki, Heck, Fujiwara-Moritani, and Sonogashira), C À N and C À S coupling reactions. The ligand was found to be inexpensive, thermally stable, easy to synthesize from easily accessible starting materials on a multigram scale, show simplicity in use, and robustness in application, making this ligand effective for different coupling reactions. Suitably, the donor ability of the N=N bond of the benzotriazole ring and lone pair of electrons on the N of the pyridine ring enhance the bidentate ability of the ligand.

A regioselective tandem synthesis of highly functionalized pyrrolo[1,2-a]quinolines has been developed through a novel strategy by palladium-catalyzed [3 + 2] annulation of iodo-pyranoquinolines and internal alkynes with subsequent ring opening. Pyranoquinoline with n-alkyl substitution at the 3-position leads to the formation of pyrrolo-acridones via [3 + 2] annulations/ring opening and successive intramolecular cross-aldol condensation.

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