Practical syntheses of [C-13]- and [C-14]-labelled glucosphingolipids

Synthetic routes to [glucose-U-C-14]-1-O-(beta-D-glucopyranosyl)-N-stearoyl -D-erythro-sphingosine 1b and to [glucose-C-13(6)]-1-O-(beta-D-glucopyranos yl)sphingosine ([glucose-C-13(6)]glucopsychosine, 2b) are described. Wherea s the protected ceramide precursor for 1b was prepared using conventional m ethodology, two new strategies were developed in the course of the synthesi s of 2b. Of these, one relies on keeping a protecting group in place at all times to avoid the handling difficulties associated with sphingosine 4, wh ile the other generates a protected derivative (24) of sphingosine indirect ly by means of a Mitsunobu inversion.