cf. CA 59, 13912b.Forty derivatives of benzofuran (I) were prepared (details not given).The compounds (structural formulas indicated) were phenolic or basic derivatives of halogenated or nonhalogenated 2-alkyl-3-benzoyl-I or benzofuryl chalcones, some of which were isomers of flavones.Data are given for the effects of the 40 compounds, orally or by other routes, upon the capillary fragility and permeability of rabbits and rats.When the capillary fragility and permeability were increased by various exptl, procedures (details given), the compounds showed either palliative or preventive effects depending upon the exptl. conditions.Mechanisms of the vitamin P-like action of certain of the compounds are interpreted in relation to their chem. structures.The maximum pharmacodynamic activity and lowest toxicity occurred with 2-ethyl-3-(4'-hydroxybenzoyl)-I.Data are given for the L.D.50 values of certain of the compds, in mice.18 references.