Regiospecific strategies for the synthesis of novel dihydropyrimidinones and pyrimidopyridazines catalyzed by molybdate sulfuric acid

The one-pot reactions of aryl glyoxals with acetylacetone and urea using molybdate sulfuric acid (5 mol %) lead to the novel functionalized 5-acetyl-4-(aryloyl)-3,4-dihydropyrimidinones, which readily undergo the Knorr condensation with hydrazines to produce new pyrimido[4,5-d]pyridazines. The present strategies are in accordance with green chemistry principles through the use of a safe and recyclable catalyst under solvent-free conditions.     

Three‐Step Synthesis of Novel 2‐Aryl‐3‐benzamidobenzofurans: Regiospecific Reactions Catalyzed by Molybdate Sulfuric Acid

A solvent‐free and synthetic pathway to novel benzofuran derivatives, starting from oxidation of phenyl ketones to arylglyoxals in three steps was developed. The molybdate sulfuric acid catalyzed the reaction of arylglyoxals with benzamide and phenols to afford 2‐aryl‐3‐benzamidobenzofurans in high yield. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, ¹H NMR, and ¹³C NMR spectral data. The present methodology offers several advantages such as non‐hazardous reaction condition, simple operation, and work‐up procedure.