Determination of the free radical scavenging activity of dihydropyran-2,4-diones.

The antioxidant activities of four synthetic dihydropyran-2,4-diones have been established through the determination of their abilities to inhibit free radicals using DPPH(*) as the stable radical. Whilst all of the compounds exhibited high inhibition percentages, the most active member of the group was 6-phenyl-dihydropyran-2,4-dione. The antioxidant activity of the dihydropyran-2,4-diones is reported here for the first time and extends our knowledge of the range of valuable biological activities associated with this group of compounds.

Synthesis and evaluation of the molluscicidal activity of the 5,6-dimethyl-dihydro-pyran-2,4-dione and 6-substituted analogous.

Five dihydro-piran-2,4-diones, including 5,6-dimethyl-dihydro-piran-2,4-dione one of the intermediates of the synthesis of caloverticilic acid, were synthesized and submitted to molluscicidal bioassay. The compound's yields varied from moderate to good (42%- 80%) and were achieved through the preparation of the dianion of ethyl acetoacetate, reaction with and aldehyde followed by hydrolysis of the ester (NaOH, H(2)O, 2 h, T.A.