The synthesis of novel hexa-13C-labelled glucosinolates from [13C6]-D-glucose

An isotopically labelled building block, 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-[C-13(6)]glucopyranose (4), is obtained from the commercially available [C-13(6)]-D-glucose. This hexa-C-13-labelled thioglucose can be employed to make any glucosinolate (8) for use as an internal standard for isotopic dilution LCMS analysis. Herein three typical glucosinolates in their hexa-C-13-labelled form: [glucose-C-13(6)]gluconasturtiin, [glucose-C-13(6)]sinigrin and [glucose-C-13(6)]glucoerucin are synthesised by coupling the isotopically labelled thioglucose (4) with the corresponding hydroximoyl chlorides followed by sulfation with pyridine sulfur trioxide and deacetylation with a catalytic amount of potassium methoxide, respectively. (C) 2009 Elsevier Ltd. All rights reserved.