Enolethers.<b>XXI</b>. Synthesis of 5,5′-disubstituted 4,4′-bipyrimidines
作者:Franz Effenberger、Ingrid Barthelmess
DOI:10.1002/jhet.5570320239
日期:1995.3
amidines 4a-c and S-methylisothiourea (4d), respectively, to give 2,2′-disubstituted 5,5′-dimethyl-4,4′-bipyrimidines 5a-d. The dihydrofuran and dihydropyran derivatives 3c and 3d, however, react with benzamidine (4c) in dimethylformamide only in the presence of calcium hydride as condensation agent yielding 5,5′-bis(2-hydroxyethyl)- and 5,5′-bis(3-hydroxypropyl)-2,2′-diphenyl-4,4′-bipyrimidine 6a and b.
通过将烯醇醚1与草酰氯酰化并随后使用三乙胺消除氯化氢,可轻松获得1,6-二烷氧基-3,4-二酮3。将开链的2,5-二甲基衍生物3b分别与am4a -c和S-甲基异硫脲(4d)转化,得到2,2'-二取代的5,5'-二甲基-4,4'-联嘧啶5a -d。但是,二氢呋喃和二氢吡喃衍生物3c和3d与苯甲idine (4c)反应仅在氢化钙作为缩合剂存在下于二甲基甲酰胺中生成5,5'-双(2-羟乙基)-和5,5'-双(3-羟丙基)-2,2'-二苯基-4,4'-联嘧啶6a和b。