Cellulose Sulfuric Acid: An Efficient Biodegradable and Recyclable Solid Acid Catalyst for the Synthesis of 1-Oxo-hexahydroxanthene

Abstract

A series of 1-oxo-hexahydroxanthene derivatives was synthesized at room temperature in solid state from substituted salicylaldehydes and substituted 1,3-hexanediones in the presence of a catalytic amount of cellulose sulfuric acid. The results showed that the reaction performed under solid-state conditions was benign to the environment, with higher yields and more convenient workup.

Keywords:

• Cellulose sulfuric acid
• 1,3-hexanedione
• 1-oxo-hexahydro xanthene
• substituted salicylaldehydes
• solid state

ACKNOWLEDGMENT

Financial assistance from the Council of Scientific and Industrial Research (Grant No. 01(2061)/06/EMR-II), New Delhi, is gratefully acknowledged.

Notes

^a Yields refer to pure solid products; all products were reported in the literature and were characterized by comparison of their physical and spectral data with those previously reported.

^a Mixture of salicylaldehyde (1 mmol), 1,3-hexanedione (2 mmol), and various catalysts such as cellulose sulfuric acid (0.08 g), methane sulfonic acid (0.1 mmol), silica sulfuric acid (0.08 g), and sulfuric acid in acetic acid (0.1 mmol) was used.

^b Isolated yield.

^a Mixture of salicylaldehyde (1 mmol), 1,3-hexanedione (2 mmol), and cellulose sulfuric acid was used, but we observed variation in catalyst loading: 0.01 g, yield 28%; 0.03 g, yield 51%; 0.05 g, yield 79%; 0.08 g, yield 96%.

^b isolated yield.

^a Mixture of salicylaldehyde (1 mmol), 1,3-hexanedione (2 mmol), and cellulose sulfuric acid (0.08 g) was ground with a pestle in a mortar.

^b Isolated yield.