Ascorbic Acid as an Efficient Organocatalyst for the Synthesis of 2‐Substituted‐2,3‐dihydroquinazolin‐4(1H)‐one and 2‐Substituted Quinazolin‐4(3H)‐one in Water

Abstract

An environmentally benign, robust and straightforward protocol has been developed for the synthesis of a diverse array of 2,3‐dihydroquinazolin‐4(1H)‐ones using 2‐aminobenzamide and various aldehydes or ketones. Water, a green solvent was adopted in this methodology replacing hazardous reaction mediums. Further, ascorbic acid, an organocatalyst has been accepted to meet the role of catalyst, thus bypassing the use of noxious metals or hazardous materials, which is another asset of this protocol. The activity of this novel methodology has been further being broadened using an oxidant oxone to synthesize 2‐substituted quinazolin‐4(3H)‐one from aldehyde.

An eco‐friendly, sustainable, and greener approach to the synthesis of Dihydroquinazolin‐4(1H)‐ones using a deep eutectic solvent

“…Erfan et al [38] reported a highly efficient synthetic route using SBA‐16/GPTMS‐TSC‐CuI solvent‐free protocols, which provided an impressive yield of 98% in 20 min. Pariyar et al [39] used ascorbic acid at 90°C in H 2 O to give 92% quinazoline in 1 h. Maleki et al [40] used nano‐Fe 3 O 4 @GO under reflux in EtOH and yielded 80% in 3 h. Sharma et al [41] achieved a DHQ using cyanuric chloride at room temperature in CH 3 CN with a yield of 96% in 10 min. The methods show some common drawbacks such as expensive catalysts, tedious catalyst separation procedures, use of hazardous solvents, acidic reaction conditions, longer reaction time, non‐selectivity, etc.…”

Microwave‐Assisted Green Synthesis of 2,3‐Dihydroquinazolinones under Base‐ and Catalyst‐Free conditions

“…Examples include NH 4 Cl" [17] I 2 , [18] [Bmim] PF 6 , [13d] cellulose-SO 3 H, [3] NaHSO 4 , [19] cyanuric chloride, [20] HScellulose sulfonate, [21] morpholinoethanesulfonic acid, [22] trifluoroethanol, [23] citrus extract modified graphene oxide [24] and ascorbic acid. [25] However, a majority of synthetic methods still require expensive/hazardous catalysts, harmful solvents, long reaction times, and high temperatures. In addition, the prerequisite for some of these methods are tedious reaction quenching steps.…”