Abstract: Certain trans-6-[2-(N-heteroaryl-3,5-disubstituted) pyrazol-4-yl)ethyl]- or ethenyl]tetrahydro-4-hydroxy-2H-pyran-2-ones and the corresponding ring-opened acids, esters and N-oxides derived therefrom which are potent inhibitors of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG CoA reductase) and are thus useful hypolipidemic or hypocholesterolemic agents. Pharmaceutical compositions containing such compounds, and a method of inhibiting the biosynthesis of cholesterol employing such pharmaceutical compositions are also disclosed.

Abstract: The (2S)-(-)-isomer of (5-amino-1,2-dihydro-2-methyl-3-phenylpyrido[3,4-b]pyrazin-7-yl)carbamic acid, ethyl ester is significantly more potent than either the (2R)-(+)-isomer or the (R,S)-(.+-.)-racemic mixture in inhibiting mitotic cell division of L1210 leukemia cells.The compound, pharmaceutical compositions containing the compound, and a method of ameliorating cancer diseases in mammals are disclosed.