Application of Ball Milling Technology to Carbohydrate Reactions: I. Regioselective Primary Hydroxyl Protection of Hexosides and Nucleoside by Planetary Ball Milling‡

^‡Presented at the CARBO XXI Conference, Annual Meeting of the Association of Carbohydrate Chemists & Technologists, India, November 26–29, 2006, New Delhi, India.

Abstract

Dry ball milling of hexosides with trityl chloride in the presence of DABCO or Na₂CO₃ has been found to result in their complete conversion to the respective 6‐O‐trityl ethers. Further wet grinding of the reaction mixture with Ac₂O in the presence of DMAP led to the respective fully protected hexosides in good to excellent yields after isolation. It has been found to be an effective one‐pot two‐step synthesis under solvent‐free condition. The speed of homogenization has been shown to highly influence the rate and outcome of the reaction, and commercially available planetary ball mill has been proved to be very convenient for carrying out the reaction under standardized and reproducible conditions.

Keywords:

• Trityl ethers
• Regioselective reactions
• Ball mill
• Solvent‐free synthesis
• Mechanochemical reactions

Acknowledgment

Premanand Ramrao Patil would like to thank NIPER for a research fellowship.

Notes

^‡Presented at the CARBO XXI Conference, Annual Meeting of the Association of Carbohydrate Chemists & Technologists, India, November 26–29, 2006, New Delhi, India.