| 摘要 |
NEW MATERIAL:A compound of formulaI(R<1> is 1 or 2H-tetrazol-5-yl, carboxyl; R<2> is 4 or more carbon alkyl, cycloalkyl, alkylthio, aryl or heteroaryl which may have substituents) and its salt. EXAMPLE:2-tert. -Butyl-6-(1H-tetrazol-5-yl)-5H-[1, 3, 4]thiadiazolo[3, 2-a] pyrimidine-5-one. USE:Antiallergic agent: it inhibits the liberation of chemical mediators caused by antigen-antibody reactions. PREPARATION:A compound of formula II (R<5> is 2-tert.-butyl-2H-tetrazol-5-yl) is heated with an acid such as sulfuric or p-toluenesulfonic acid in the presence or absence of a solvent such as water. Dowtherm-A or solfolane , at 70- 180 deg.C for 30min to 10hr to give the compound of formulaI. |
