IN PURSUIT OF HIGHER PURITY - USE OF C-13 NMR AND C-13-ENRICHED SUBSTRATES TO TRACE IMPURITY GENERATION AND REMOVAL IN THE SYNTHESIS OF ATORVASTATIN

The use of C-13-labeled starting materials and intermediates in the sy nthesis of the lipid regulator atorvastatin is described, C-13 NMR of the C-13 enriched intermediates allowed monitoring of problematic nonc hromophoric low-level impurities which were unobservable using standar d analytical techniques.