| abstract |
NEW MATERIAL:2,2'-Phenylethenylidenebis(3,1-benzoxazin-4-one) shown by the formula I. n USE: An antiallergic agent. n PREPARATION: (a) 2,2'-[(1,3-Dioxo-2-phenylmetylene-1,3-propanediyl)diimino]- benzoic acid shown by the formula II is dehydrated in a nonaqueous solvent by heating preferably while distilling away water or by treating with a dehydrat ing agent, to give a compound shown by the formula I. Or, (b) 2,2'-methylene-bis (3,1-benzoxazin-4-one) shown by the formula I. n COPYRIGHT: (C)1986,JPO&Japio |