injection after 60 minutes from the administration of the medicine 1 ml of a 0 1 u03bcg ml paf solution was administered and then the maximum blood pressure depression was determined for a control test the vehicle 10 nikkol u00ae liquid was administered in place of the compound of example 1 the test compound was intravenously administered 30 mg kg to a rabbit or orally administered 50 mg kg to a guinea pig blood samples were collected and the extent of platelet aggregation caused by 10 12 10 6 m of paf was examined the results are shown in table 2 the numerical values in the table show the paf concentrations ec 50 nm necessary for causing an aggregation corresponding to 50 of the maximum paf reaction table 2______________________________________the change with time of inhibitory effectec sub 50 value of the compound of example 1on platelet aggregation caused by paf time elapsed after admini stration of compound of administration example 1 hr animal route and dose 0 0 5 1 2 4______________________________________rabbit intravenous 6 2 26 20 16 14 administration 30 mg kgguinea oral admini 0 23 10 17 3 1pig stration 50 mg kg______________________________________ as stated in the foregoing the compound i of this invention shows a powerful and highly selective paf antagonism this antagonism has been confirmed not only in in vitro test but also in outside living body test as well as in in vivo test further the compound i of this invention shows a prolonged duration of action in living body which could not be found in prior art compounds accordingly the compound i of this invention is very useful as a preventive and curative agent for paf induced diseases for example various kinds of inflamation such as nephritis of rheumatism.