Zeolite-Catalyzed Method for the Preparation of 2,3-Dihydroquinazolin-4(1H)-ones

Pd(II)-Catalyzed Cascade Annulation of o-Aminobenzoic Acids with CO, Amines, and Aldehydes to N3-/N1,N3-Substituted 2,3-Dihydroquinazolin-4(1H)-ones

The unprecedented Pd(II)-catalyzed cascade annulation of o-aminobenzoic acids with CO, amines, and aldehydes has been developed. This protocol provides an efficient and concise approach to selective construction of N3-substituted and N1,N3-disubstituted 2,3-dihydroquinazolin-4(1H)-ones mostly in moderate to excellent yields from simple and easily available starting materials under mild conditions featured with low cost, high step economy, broad substrate scope, and good product diversity.

Photooxidation of 2,3-dihydroquinazolin-4(1H)-ones: retention or elimination of 2-substitution

A series of mono and disubstituted 2,3-dihydroquinazolin-4(1H)-ones (DHQZs) were synthesized and the electronic and steric effects of the C₂- and N₃-substitutions on the retention or elimination of the C₂-substitution by exposing them to the ultraviolet light were investigated. Electron transfer from photo-excited dihydroquinazolinones to chloroform solvent is proposed, in which both lone pairs on the N₁- and N₃-atoms can be involved in this process. The extent of the N₁- and N₃-atoms contributions in this electron-transfer process and also the retention or elimination of the C₂-substitutions are dependent on the nature and steric hindrance of both C₂- and N₃-substitutions. The experimental results are supported by the computational studies. Photoinduced electron-transfer reaction of a series of mono and disubstituted 2,3- dihydroquinazolin-4(1H)-ones was investigated.

3,5-Bis(trifluoromethyl) Phenylammonium triflate(BFPAT) as a Novel Organocatalyst for the Efficient Synthesis of 2,3-dihydroquinazolin-4(1H)-one Derivatives

AIMS AND OBJECTIVES

A one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives by threecomponent cyclo-condensation of isatoic anhydride, aldehydes and amine or ammonium acetate has been developed using 3,5-Bis(trifluoromethyl) phenylammonium triflate (BFPAT) as a new organocatalyst.

MATERIALS AND METHODS

All of the obtained products are known compounds and identified by IR, 1HNMR, 13CNMR and melting points.

RESULTS

A wide variety of structurally different aldehydes reacted easily and rapidly to result in the relating 2,3-dihydroquinazolin-4(1H)-ones in good to excellent yield.

CONCLUSION

We have demonstrated an extremely effective and new process for synthesizing 2,3- dihydroquinazolin-4(1H)-ones employing BFPAT as a novel organocatalyst in one-pot fashion.

2,3-Dihydroquinazolin-4(1H)-one as a privileged scaffold in drug design

2,3-Dihydroquinazolin-4-one (DHQ) belongs to the class of nitrogen-containing heterocyclic compounds representing a core structural component in various biologically active compounds. In the past decades, several methodologies have been developed for the synthesis of the DHQ framework, especially the 2-substituted derivatives. Unfortunately, multistep syntheses, harsh reaction conditions, and the use of toxic reagents and solvents have limited their full potential as a versatile fragment. Recently, use of green chemistry and alternative strategies are being explored to prepare diverse DHQ derivatives. This fragment is used as a synthon for the preparation of biologically active quinazolinones and as a functional substrate for the synthesis of modified DHQ derivatives exhibiting different biological properties. In this review, we provide a comprehensive assessment of the synthesis and biological evaluations of DHQ derivatives.