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Upstream product

• 83-72-7 2-hydroxynaphtho-1,4-quinone 
• 582-17-2 2,7-Dihydroxynaphthalene 
• 123-11-5 4-methoxy-benzaldehyde 

Relevant academic research and scientific papers

Polystyrene-supported GaCl3 as a highly efficient and reusable heterogeneous Lewis acid catalyst for the three-component synthesis of benzoxanthene derivatives

Naphthoquinone-based xanthenes, specifically 14-aryl-13H-dibenzo[a,i] xanthene-8,13(14H)-diones and 12-aryl-2,3,4,12-tetrahydro-1H-benzo[b]xanthene-1, 6,11-triones, were obtained in good to excellent yields by a simple, mild, and efficient three-component coupling procedure utilizing polystyrene-supported gallium trichloride as a highly active and eco-friendly heterogeneous Lewis acid catalyst. This reaction was also extended to the preparation of 14-aryl-2-hydroxy-13H-dibenzo[a,i]xanthene-8,13(14H)-diones. The experimental and work-up procedure is very simple and the catalyst can be easily separated from the reaction mixture and reused several times in subsequent reactions.

Efficient one-pot syntheses of dibenzo[a, i]xanthene-diones and evaluation of their antioxidant activity

Facile and convenient procedures for the synthesis of dibenzo[a,i]xanthene- diones have been described. The process employs one-pot condensation of aldehydes, 2-hydroxynaphthalene-1,4-dione, and 2-naphthol/2,7- dihydroxynaphthalene/2,6-dihydroxynaphthalene using catalytic sulfuric acid in water under reflux. Task-specific ionic liquid, 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim]HSO4), has also been found to be an effective catalyst for this transformation. The protocols defined herein prove to be efficient in terms of high yields, operational simplicity, easy workup, and short reaction time. Also, these compounds were screened for antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay.