Efficient Solid-Phase Synthesis of Diverse 2-Aminoquinazolin-4-ones from Resin-Bound Anilines

Supported Palladium-Catalyzed Tandem Synthesis of 2-(Alkylamino/amino)-3-arylquinazolin-4(3H)-ones Employing CO Source

Herein, we demonstrated heterogeneous and recyclable polystyrene-supported palladium (Pd@PS) nanoparticles (NPs) catalyzed tandem addition and intramolecular aminocarbonylative cyclization approach for the synthesis of potentially bioactive 2-(alkylamino/amino)-3-arylquinazolin-4(3H)-one analogues from 2-iodophenylcarbodiimides employing amines as nucleophiles and oxalic acid as an ex-situ CO alternative. Various cyclic/acyclic primary and secondary amines were employed and selectively produced substituted 2-(alkylamino)-3-arylquinazolin-4(3H)-ones in good to excellent yields. In addition, we extended the developed strategy to fix two ammonium carbamate and oxalic acid as gaseous NH₃ and CO sources respectively, for the synthesis of 2-amino-3-arylquinazolin-4(3H)-one derivatives. Furthermore, gram scale applicability, diverse substrate scope and high recyclability of the Pd@PS catalyst were the major achievements of the developed protocol.

Advances in the Solid-Phase Synthesis of Pyrimidine Derivatives

This Review describes the existing synthetic approaches for the solid-phase synthesis (SPS) of differently substituted and fused pyrimidine derivatives. These synthetic strategies are classified on the basis of the different synthetic routes leading to the particular type of pyrimidine heterocycle formed. The Review discusses the application of a variety of polystyrene derived supports for the construction of pyrimidine rings. The effect of microwave heating on the solid-phase synthesis is also addressed in the review.

One-pot synthesis of 2-amino-4(3H)-quinazolinones via ring-opening of isatoic anhydride and palladium-catalyzed oxidative isocyanide-insertion

An efficient and practical two-step process has been developed for the synthesis of 2-amino-4(3H)-quinazolinones via ring-opening of isatoic anhydride and palladium-catalyzed oxidative isocyanide-insertion in one pot. This regioselective procedure could construct a wide range of 2-amino-4(3H)-quinazolinones in moderate to excellent yields. Furthermore, the methodology also had distinct advantages of easily accessible starting materials and operational simplicity.

Microwave-Assisted, Boron Trichloride Mediated Acylation of Phenols−Synthesis of (o-Hydroxyaryl)(Aryl)methanones and Xanthones

A novel and efficient microwave-assisted, BCl(3) mediated coupling reaction to synthesize o-(hydroxyaryl)(aryl)methanone structures from phenols and acyl chlorides is described. This reaction was further incorporated into a two-step synthesis of biologically interesting xanthones.

Synthesis of 3-Amino-1,2,4-benzothiadi- azine 1,1-Dioxides via a Tandem Aza-Wittig/Heterocumulene Annulation

[reaction: see text] Reaction of o-azidobenzenesulfonamides with polymer-supported triphenylphosphine affords the corresponding iminophosphoranes. Subsequent reaction with isocyanates gives 3-amino-1,2,4-benzothiadiazine 1,1-dioxides in high yields and purities. The reaction has been successfully applied to the synthesis of derivatives with various substituents at the 2- and 3-positions and in the benzenoid ring.