A Clean Synthesis of 1‐Oxo‐hexahydroxanthene Derivatives in Aqueous Media Catalyzed by TEBA

Abstract

A series of 1‐oxo‐1,2,3,4,9,10‐hexahydroxanthene derivatives were synthesized from substituted salicylaldehydes and substituted 1,3‐hexanedione in water at 90°C catalyzed by TEBA. The structure of the product was confirmed by X‐ray analysis. Compared with other synthetic methods, this new method has the advantages of easier workup, milder reaction conditions, high yields (85 ∼ 95%) and environmentally benign procedure.

Keywords:

• Hexahydroxanthene
• salicylaldehyde
• TEBA
• water
• synthesis

Acknowledgment

We are grateful to the Foundation of the “Surpassing Project” of Jiangsu Province and Natural Science Foundation of the Education Committee of Jiangsu Province (04KJB150139) for financial support.

Notes

¹X‐ray crystallography for 3o: Empirical formula C₂₄H₂₈O₄, F _W  = 380.46, T = 193(2) K, Orthorhombic, space group Pbca, a = 15.559(3) Å, b = 11.1768(19) Å, c = 23.057(4) Å, α = β = γ = 90°, V = 4009.7(11) Å³, Z = 8, Dc = 1.260 Mg/m³, λ(MoKα) = 0.71070 Å, μ = 0.084 mm⁻¹, F(000) = 1632. 3.16°<θ<27.48°, R = 0.0840, wR = 0.1611. S = 1.258, Largest diff. Peak and hole: 0.503 and −0.213 e · Å⁻³