saturated methylene-bridged quinazoline-2,4-diones (7a-b) prepared from norbornane-diexo-β-amino acid (1) with isocyanates and PPA. When heated with PPA, compounds 9 can be isomerized to 7. For preparation of the unsaturated compounds 8, the amino acid 2 was converted into the acid amides (13) and cyclized with I,1'-carbonyl-diimidazole to tricyclic quinazoline-2,4-dione (8a-e), which decompose when
由双异
冰片降
冰片烷和
降冰片烯-氮杂
环丁烷酮5和6与异
氰酸芳基酯制备N-芳基
氨基甲酰基取代的β-内酰胺(9和10)。与由降
冰片烷-二exo-β-
氨基酸(1)制得的饱和亚甲基桥连
喹唑啉-2,4-二酮(7a-b)相比,该化合物的结构通过IR,NMR光谱和X射线分析得以阐明。与
异氰酸酯和
PPA。与
PPA一起加热时,化合物9可以异构化为7。为制备不饱和化合物8,
氨基酸2被转化为酰胺(13),并与I,1'-羰基-二
咪唑环合成
三环喹唑啉-2 ,4-二酮(8a-e),其在加热时分解,分解出
环戊二烯以产生3-取代的尿
嘧啶(14)。