PPTS‐Catalyzed Bicyclization Reaction of 2‐Isocyanobenzaldehydes with Various Amines: Synthesis of Diverse Fused Quinazolines

Abstract

A PPTS (pyridinium p-toluenesulfonate)-catalyzed bicyclization reaction of 2-isocyanobenzaldehydes as 1,5-dielectrophiles with various amines has been developed. The reaction not only provides a simple and efficient strategy for the assembly of structurally diverse fused quinazoline derivatives from readily available substrates under metal-free and mild conditions in a single step with only water and hydrogen as the by-products, but also opens the way to the application of o-formyl arylisocyanides in the synthesis of nitrogencontaining heterocycles.

Application of N,N-Dimethylethanolamine as a One-Carbon Synthon for the Synthesis of Pyrrolo[1,2-a]quinoxalines, Quinazolin-4-ones, and Benzo[4,5]imidazoquinazolines via [5 + 1] Annulation

“…9,10-Dichlorobenzo[4,5]imidazo [1,2-c]quinazoline (6c). 29 White solid (111 mg, 77%). M p 206−208 °C; purification by silica gel chromatography (eluent: petroleum ether/EtOAc = 4:1 to 2:1); 1 H NMR (400 MHz, DMSO-d 6 ) δ 9.73 (s, 1 H), 8.84 (s, 1 H), 8.55 (d, J = 7.6 Hz, 1 H), 8.26 (s, 1 H), 8.00 (d, J = 8.4 Hz, 1 H), 7.92 (t, J = 7.8 Hz, 1 H), 7.80 (t, J = 7.6 Hz, 1 H); 13 C{ 1 H} NMR (100 MHz, DMSO-d 6 ) δ 148.0, 143.…”

DTBP‐promoted Passerini‐type reaction of isocyanides with aldehydes: Synthesis of α‐acyloxycarboxamides

“…[ 17 ] However, these reactions are limited to aliphatic isocyanides (Scheme 1, (1)). With our continued interest in the synthetic applications of isocyanides [ 18 ] and multicomponent reactions, [ 19 ] herein we report a DTBP‐promoted Passerini‐type reaction of isocyanides with two molecular aldehydes. The reaction demonstrates the wide scope of various isocyanides, especially aromatic isocyanides, and provides an efficient strategy for the synthesis of α‐acyloxycarboxamides with two identical functional groups in a single step (Scheme 1, (2)).…”

Cobalt-Catalyzed Isocyanide-Based Three-Component Cascade for the Synthesis of Quinazolines

“…In addition, compounds containing a quinazoline framework ( IV and V ) were known to exhibit anti-inflammatory and antitumor activities . Hence, various procedures for the assembly of the quinazoline core have been developed. − However, the existing methods show lower atom and step economy and often suffer from a limited substrate scope. Thus, development of a concise, highly efficient, environmentally benign, and economically acceptable method is highly desirable.…”