Direct regioselective 2-O-(p-toluenesulfonylation) of sucrose.
2-O-(p-Toluenesulfonyl)sucrose was regioselectively synthesized by direct p-toluenesulfonylation of sucrose using N-(p-toluenesulfonyl)imidazole in the presence of molecular sieves at 40 degrees C. The reactivities of the sucrose hydroxy groups toward this sulfonylation increased in the order as follows: OH-2>>OH-1'>OH-3'>OH-6>OH-6'. These results were diametrically opposite to the expected sulfonylation with p-toluenesulfonyl chloride in pyridine, for which the reactivity increased in the order as follows: OH-6', OH-6>>OH-1'>OH-2. The desired 2-O-(p-toluenesulfonyl)sucrose was readily isolated by simple open reversed-phase column chromatography, followed by recrystallization, thus overcoming the main difficulties associated with regioselectivity, efficiency, and isolation techniques for the practical preparation.
Teranishi
Katsunori
K
Faculty of Bioresources, Mie University, 1515 Kamihama, Tsu, Mie 514-8507, Japan. teranisi@bio.mie-u.ac.jp
D007093:Imidazoles / Q000737:chemistry*; D013395:Sucrose / Q000737:chemistry*; D014105:Tosyl Compounds / Q000737:chemistry*
D007093:Imidazoles; D014105:Tosyl Compounds; C025506:4-toluenesulfonyl chloride; D013395:Sucrose