Quinazolinone-Directed C-H Activation: A Novel Strategy for the Acetoxylation-Methoxylation of the Arenes

Abstract

2-Aryl-4-quinazolinones undergo smooth acetoxylation in the presence of 5 mol% Pd(OAc) 2 and a stoichiometric amount of PhI(OAc) 2 via C-H activation to produce the corresponding acetoxy-substituted 4(3H)-quinazolinone derivatives in good yields with high regioselectivity.

Redox-Induced Aromatic C–H Bond Functionalization in Metal Complex Catalysis from the Electrochemical Point of View

“…Thus, it is obvious that such weak oxidants as oxygen (−0.78 to −1.26 V), 1,4-benzoquinone (0.16 to −0.875V) are not able to oxidize many palladacycles even up to Pd(III) (~0.25 to 1.4 V) complexes, the more so to Pd(IV) (~1.0 to 1.6V) [25]. This explains the numerous failed attempts to use them in such Pd-catalysed C-H functionalizations, such as 1,4-benzoquinone [27][28][29]75,[82][83][84][85], and O 2 [77,82,[86][87][88] for example.…”

“…At the same time, a mild oxidant, AgOAc, is sufficient for the success of many Pd(OAc) 2 -catalyzed reactions, especially in CH 2 Cl 2 or DCE [97][98][99], passing through Pd(III) but not Pd(IV) intermediates, for which its strength is not enough [74,75,87,100,101].…”

“…Only two Pd(II) intermediates and a Pd(II)/Pd(0) cycle were proposed for these reactions [31]. In 2011/2012, Reddy's team proposed a Pd(II)/Pd(0) catalytic cycle for N-(2-benzoylphenyl)benzamides [74] and 2-arylquinazolin-4(3H)-ones substrates [75], but nevertheless proposed a Pd(IV) intermediate for the alkoxylation of 1-aryl-3,4-dihydroisoquinolines [76]. However, no evidence was provided.…”

2-Aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1<i>H</i>)-ones as substrates for the synthesis of 2,6,8-triarylquinazolin-4-ones

“…12.35 ppm. The analogous 2-arylquinazolin-4(3H)-one derivatives bearing an aryl group at the 6-position of the fused benzo ring have been found to serve as orally available ghrelin receptor anatagonists for the treatment of diabetes and obesity [33]. In summary, the results of this investigation demonstrate that anthranilamide readily undergoes bromination to afford 2-amino-3,5-dibromobenzamide in high yield and purity without affecting the amide nitrogen.…”

Quinazoline‐Directed C–H Bond Functionalization Catalyzed by Ruthenium(II) Carboxylate – Construction of Polyconjugated Aryl‐Heteroaryl Systems

“…Only limited examples, however, of the quinazoline ring acting as a directing group in a C–H functionalization have been demonstrated. Reddy and co‐workers reported the Pd‐catalyzed ortho ‐selective direct acetoxylation and methoxylation of 2‐arylquinazolinones . The selective ortho ‐monoarylation of the 2‐aryl group of 2,4‐diarylquinazolines by using aryl iodides was achieved in the presence of Pd(OAc) 2 and Ag 2 CO 3 in trifluoroacetic acid according to Peng and co‐workers .…”