Sucrose 6 Hydroxyl Protection And Deprotection Reaction And The Synthesis Of Sucralose Applications

Sucralose, a trichlorinated derivative of sucrose (4,1', 6'-trichloro-4,1', 6'-trideoxy-galacto-sucrose), is emerging as the most powerful and the most commerciallyuseful artifical sweetener in the world.The methods of the protection and deprotection of hydroxyl group in the 6 position ofsucrose were studied in this thesis and were also applied to the synthesis of sucralose.Sucralose was prepared by reacting sucrose with a trialkyl orthoacylate, chloration,acylation and deacylation. The total yield is 39.3% by optimizing reaction conditions ofeach step.A new synthetic route was designed for the preparation of sucrose-6-ester, the keyintermediate of sucralose. Sucrose-6-esters and other products were highly selectivelyprepared in one step by using N-acyl-thiozolidine-2-thione as a new acylating reagent,which could be recycled to save the cost.Sulfuric acid immobilized on silica gel was used as a new catalyst for the preparationof sucrose octaacetate. Prior to early catalyst such as sulfuric acid or sodittm salt, it notonly avoids large excess acetic anhydride but also simplifies the after-treatment. Thereaction time is less and the yield is higher. And the possibility of preparation ofsucrose-6-ester by using sucrose octaacetate was studied.The structure of 6-esters in vacuo and in aqueous solution were simulated andoptimized by using molecular modeling software, Hyperchem. The bond length and energywere also calculated. These studies provide some theory proof for future research.