Palladium(II) N^O Chelating Complexes Catalyzed One-Pot Approach for Synthesis of Quinazolin-4(3H)-ones via Acceptorless Dehydrogenative Coupling of Benzyl Alcohols and 2-Aminobenzamide

Abstract

A convenient protocol for the one-pot synthesis of quinazolin-4(3H)-ones using palladium(II) complexes via dehydrogenative coupling of readily available benzyl alcohols and 2-aminobenzamide has been described. New structurally related Pd(II) N^O chelating complexes of general configuration [Pd(L)Cl(PPh 3 )](where L = dimethylamino benzoylhydrazone ligands) have been designed and synthesized. The formation of the complexes has been recognized by analytical and spectral methods (FT-IR, NMR& HR-MS). The presence of a square-planar geometry around palladium (II) ion was confirmed by single crystal X-ray diffraction study. A wide range of substituted quinazolinones have been successfully achieved from diverse range of benzyl alcohols in good to excellent yields using 1.0 mol% of catalyst loading under aerobic conditions. Furthermore, control experiments reveal that the dehydrogenative coupling reaction involves initially via the formation of aldehyde intermediate and subsequent formation of cyclic aminal intermediate.

Synthesis and characterization of novel hercynite@sulfuric acid and its catalytic applications in the synthesis of polyhydroquinolines and 2,3-dihydroquinazolin-4(1H)-ones

“…An interesting protocol involves the cyclocondensation of aryl aldehydes with anthranilamide towards a library of 2,3-dihydroquinazolin-4(1H)-ones. [17][18][19] In this method, anthranilamide is considered as a green reagent because, on the basis of the cyclic mechanism, this reaction gives only water as the by-product. 20 In order to derive the mentioned reactions, acid catalysts which dominate these reactions can be regarded as standard methods, evaluating the reactivity of Brønsted-Lowry acid species as potential catalysts.…”

Ru(II)–NNO pincer‐type complexes catalysed E‐olefination of alkyl‐substituted quinolines/pyrazines utilizing primary alcohols

“…Among the three complexes, we found that complex 2 was the most effective catalyst for this reaction because the electron‐donating group (–OCH 3 ) enhances the catalytic activity. [ 22 ]…”

UV-Light-Induced Dehydrogenative N-Acylation of Amines with 2-Nitrobenzaldehydes To Give 2-Aminobenzamides

“…In addition, the X-ray structure of 4a was presented in Supporting Information. Next, we developed various alkyl primary amines (3). Butylamine was added to this reaction mixture, and it displayed moderate yield (76% for 5a).…”

“…[1][2][3][4][5][6][7][8][9][10][11] These skeletons could be easily synthesized from 2-aminobenzamides. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Besides, these 2-aminobenzamides scaffolds also exist in various biological active agents such as anticancer, antimicrobial, anti-inflammatory, anticonvulsant, anti-tubercular, antiviral, and antimalarial agents. 1,6,9,11 Therefore, the synthesis of 2-aminobenzamides plays an important role in organic synthesis.…”