Sulfur‐Promoted Synthesis of 2‐Aroylquinazolin‐4(3H)‐ones by Oxidative Condensation of Anthranilamide and Acetophenones

Abstract

A sulfur‐promoted three‐component reaction of isatoic anhydride, primary aliphatic or aromatic amines, and acetophenones leading to densely substituted 3‐substituted 2‐aroylquinazolin‐4(3H)‐ones is reported. The key step involves a cascade reaction of selective oxidation of the methyl group of the acetophenones, followed by a condensation with anthranilamides. The scope of the reaction is applicable to the synthesis of tryptanthrin and various 3‐unsubstituted 2‐aroylquinazolin‐4(3H)‐ones.magnified image

Synthesis of 2-Amino-5-acylthiazoles by a Tertiary Amine-Promoted One-Pot Three-Component Cascade Cyclization Using Elemental Sulfur as a Sulfur Source

“…According to the above-mentioned experimental observations and previous reports, we suggest a possible reaction pathway (Scheme ). First, the elemental sulfur incorporates the nucleophilic NMM to form the active 4-methylmorpholine N–S species, which mediates the transfer of the sulfur atom to enaminone and provides intermediate V via the enaminone’s isomeric version 1′ .…”

Recent Advances in the Synthesis of Heterocycles via Reactions Involving Elemental Sulfur

“…The methyl group of an acetophenone or pinacolone 354 could be oxidized with elemental sulfur in DMSO (Scheme 131). [152] In the presence of an anthranilamide 355 as s bis-nucleophile, the corresponding product could be formed. The reaction required N-meth- ylpiperidine in stoichiometric amount as a sulfur activator.…”

DMSO arbitrated Oxidative Annulation Followed by Homologated N-Alkylation: Microwave-Assisted Efficient and Greener Approach to Access 3-(3-Oxo-3-arylpropyl) Quinazolinones

“…Condensation of aryl methyl ketones with anthranilamide in the presence of a carbon source could be one such solution. In the literature two independent reports proposed iodine- 13 and sulfur-promoted 14 synthesis of 2-aroylquinazolin-4(3 H )-one from anthranilamide and acetophenones, respectively. More recently, iodine-mediated oxidative synthesis of 2-aryl quinazolin-4(3 H )-one, 15 and Hβ-zeolite-catalyzed synthesis of 2,3-dihydroquinazolin-4(1 H )-ones 16 were reported from the same starting materials.…”