“On-Water” Synthesis of Quinazolinones and Dihydroquinazolinones Starting from o-Bromobenzonitrile

Abstract

A versatile and practical “on-water” protocol was newly developed to synthesize quinazolinones using o-bromobenzonitrile as a novel starting material. Studies have found that air as well as water plays an important role in synthesis of quinazolinones. Further investigation indicated that dihydroquinazolinones can be prepared with this protocol under the protection of N2. The protocol can be extended to other substrates and various quinazolinones and dihydroquinazolinones were obtained. o-Bromobenzamide, o-aminobenzonitrile, and o-aminobenzamide were also evaluated as starting materials, and the results further proved the versatility of this protocol, especially towards dihydroquinazolinones.

Recent Advances and Prospects of Organic Reactions “On Water”

“…An on water protocol was established for the selective production of 2,3‐dihydro‐quinazolin‐4(1 H )‐ones 171 or their oxidized products quinazolin‐4(3 H )‐ones 170 by the reaction of various aryl aldehydes as well as several substituted o ‐bromobenzonitriles (Scheme ) . Water and air was necessary for the formation of oxidized products.…”

Glucose as an Eco‐Friendly Reductant in a One‐Pot Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones

“…Thus, we aimed at developing a one‐pot reaction involving d ‐glucose as an eco‐friendly reductant. Dihydroquinazolinones have been obtained from various precursors for the central bicyclic ring system including 2‐aminobenzamides, [ 18 ] isatoic anhydride, [ 19 ] o ‐halobenzonitriles, [ 20 ] 2‐nitrobenzamide, [ 21 ] and 2‐aminobenzonitrile. [ 22 ]…”

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

“…Among them, quinazolinones and their derivatives are an important class of compounds found in a large number of natural products . Significantly, a diverse range of molecules with quinazolin-4­(3 H )-ones display a broad spectrum of bioactivities. − (Figure ) Therefore, a vast number of synthetic approaches have been established due to the immense biological needs of quinazolinone and its derivatives in various fields. , However, all these methodologies suffer in providing the desired products of quinazolinone due to low yield, long reaction time, multistep reaction sequences, need of oxidants like DDQ, CuCl 2 , MnO 2 , KMnO 4 , I 2 , and t -BuOOH. − Further, limitation associated with the above synthetic routes is the use of unstable aldehydes through oxidation of alcohols using toxic oxidants.…”